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  • 1.
    Broering Chaar, Ana Beatriz
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Department of Materials Science and Engineering, D3.3 Saarland University, Saarbrücken, Germany.
    Syed, Muhammad Bilal
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Hsu, Tun-Wei
    Johansson-Jöesaar, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Seco Tools AB, SE-737 82 Fagersta, Sweden.
    Andersson, Jon M.
    Seco Tools AB, SE-737 82 Fagersta, Sweden.
    Henrion, Gérard
    Institute Jean Lamour, Campus ARTEM, University of Lorraine, CNRS, F-54011 Nancy, France.
    Johnson, Lars J. S.
    Sandvik Coromant, SE-126 80 Stockholm, Sweden.
    Mücklich, Frank
    Department of Materials Science and Engineering, D3.3 Saarland University, D-66123 Saarbrücken, Germany.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    The Effect of Cathodic Arc Guiding Magnetic Field on the Growth of (Ti0.36Al0.64)N Coatings2019In: Coatings, ISSN 2079-6412, Vol. 9, no 10, article id 660Article in journal (Refereed)
    Abstract [en]

    We use a modified cathodic arc deposition technique, including an electromagnetic coil that introduces a magnetic field in the vicinity of the source, to study its influence on the growth of (Ti0.36Al0.64)N coatings. By increasing the strength of the magnetic field produced by the coil, the cathode arc spots are steered toward the edge of the cathode, and the electrons are guided to an annular anode surrounding the cathode. As a result, the plasma density between the cathode and substrate decreased, which was observed as a lateral spread of the plasma plume, and a reduction of the deposition rate. Optical emission spectroscopy shows reduced intensities of all recorded plasma species when the magnetic field is increased due to a lower number of collisions resulting in excitation. We note a charge-to-mass ratio decrease of 12% when the magnetic field is increased, which is likely caused by a reduced degree of gas phase ionization, mainly through a decrease in N2 ionization. (Ti0.36Al0.64)N coatings grown at different plasma densities show considerable variations in grain size and phase composition. Two growth modes were identified, resulting in coatings with (i) a fine-grained glassy cubic and wurtzite phase mixture when deposited with a weak magnetic field, and (ii) a coarse-grained columnar cubic phase with a strong magnetic field. The latter conditions result in lower energy flux to the coating’s growth front, which suppresses surface diffusion and favors the formation of c-(Ti,Al)N solid solutions over phase segregated c-TiN and w-AlN.

  • 2.
    Calamba, Katherine
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Univ Lorraine, France.
    Jöesaar Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Bruyere, S.
    Univ Lorraine, France.
    Pierson, J. F.
    Univ Lorraine, France.
    Boyd, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Andersson, J. M.
    SECO Tools AB, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    The effect of nitrogen vacancies on initial wear in arc deposited (Ti-0.52,Ti- Al-0.48)N-y, (y < 1) coatings during machining2019In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 358, p. 452-460Article in journal (Refereed)
    Abstract [en]

    Nitrogen deficient c-(Ti0.52Al0.48)Ny, y = 0.92, y = 0.87, and y = 0.75 coatings were prepared in different N-2/Ar discharges on WC-Co inserts by reactive cathodic arc deposition. The microstructure of the y = 0.92 coating show that spinodal decomposition has occurred resulting in the formation of coherent c-TiN- and c-AIN rich domains during cutting. The y = 0.87 and y = 0.75 coatings have exhibited a delay in decomposition due to the presence of nitrogen vacancies that lowers the free energy of the system. In the decomposed structure, grain boundaries and misfit dislocations enhance the diffusion of elements from the workpiece and the substrate (e.g. Fe, Cr, and Co) into the coatings and it becomes more susceptible to crater wear. The y = 0.87 sample displays the highest crater wear resistance because of its dense grain boundaries that prevent chemical wear. The y = 0.92 sample has the best flank wear resistance because the decomposition results in age hardening. The y = 0.75 sample contains the MAX-phase Ti(2)AIN after cutting. The chemical alteration within the y = 0.75 sample and its high amount of macroparticles cause its low wear resistance. The different microstructure evolution caused by different amount of N-vacancies result in distinctive interactions between chip and coating, which also causes difference in the initial wear mechanism of the (Ti,Al)/N-y coatings.

  • 3.
    Calamba, Katherine
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Univ Lorraine, France.
    Pierson, J. F.
    Univ Lorraine, France.
    Bruyere, S.
    Univ Lorraine, France.
    Le Febvrier, Arnaud
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Barrirero, Jenifer
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Saarland Univ, Germany.
    Muecklich, F.
    Saarland Univ, Germany.
    Boyd, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Jöesaar Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Dislocation structure and microstrain evolution during spinodal decomposition of reactive magnetron sputtered heteroepixatial c-(Ti-0.37,Al-0.63)N/c-TiN films grown on MgO(001) and (111) substrates2019In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 125, no 10, article id 105301Article in journal (Refereed)
    Abstract [en]

    Heteroepitaxial c-(Ti-0.37,Al-0.63)N thin films were grown on MgO(001) and MgO(111) substrates using reactive magnetron sputtering. High resolution high-angle annular dark-field scanning transmission electron micrographs show coherency between the film and the substrate. In the as-deposited state, x-ray diffraction reciprocal space maps show a strained epitaxial film. Corresponding geometric phase analysis (GPA) deformation maps show a high stress in the film. At elevated temperature (900 degrees C), the films decompose to form iso-structural coherent c-Al- and c-TiN-rich domains, elongated along the elastically soft amp;lt;100amp;gt; directions. GPA analysis reveals that the c-TiN domains accommodate more dislocations than the c-AlN domains. This is because of the stronger directionality of the covalent bonds in c-AlN compared with c-TiN, making it more favorable for the dislocations to accumulate in c-TiN. The defect structure and strain generation in c-(Ti,Al)N during spinodal decomposition is affected by the chemical bonding state and elastic properties of the segregated domains.

  • 4.
    Calamba, Katherine
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. University of Lorraine, France.
    Schramm, Isabella
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Saarland University, Germany.
    Johansson Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Ghanbaja, J.
    University of Lorraine, France.
    Pierson, J. F.
    University of Lorraine, France.
    Mucklich, F.
    Saarland University, Germany.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Enhanced thermal stability and mechanical properties of nitrogen deficient titanium aluminum nitride (Ti0.54Al0.46Ny) thin films by tuning the applied negative bias voltage2017In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 122, no 6, article id 065301Article in journal (Refereed)
    Abstract [en]

    Aspects on the phase stability and mechanical properties of nitrogen deficient (Ti0.54Al0.46)N-y alloys were investigated. Solid solution alloys of (Ti,Al)N were grown by cathodic arc deposition. The kinetic energy of the impinging ions was altered by varying the substrate bias voltage from -30V to -80 V. Films deposited with a high bias value of -80V showed larger lattice parameter, finer columnar structure, and higher compressive residual stress resulting in higher hardness than films biased at -30V when comparing their as-deposited states. At elevated temperatures, the presence of nitrogen vacancies and point defects (anti-sites and self-interstitials generated by the ion-bombardment during coating deposition) in (Ti0.54Al0.46)N-0.87 influence the driving force for phase separation. Highly biased nitrogen deficient films have point defects with higher stability during annealing, which cause a delay of the release of the stored lattice strain energy and then accelerates the decomposition tendencies to thermodynamically stable c-TiN and w-AlN. Low biased nitrogen deficient films have retarded phase transformation to w-AlN, which results in the prolongment of age hardening effect up to 1100 degrees C, i.e., the highest reported temperature for Ti-Al-N material system. Our study points out the role of vacancies and point defects in engineering thin films with enhanced thermal stability and mechanical properties for high temperature hard coating applications. Published by AIP Publishing.

  • 5.
    Chen, Yu-Hsiang
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Roa, J. J.
    Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya, Campus Diagonal Besòs-EEBE, 08019 Barcelona, Spain / Centre for Research in Multiscale Engineering of Barcelona, Universitat Politècnica de Catalunya, Campus Diagonal Besòs-EEBE, Barcelona, Spain.
    Chen, Yu-Hsiang
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson-Jõesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Andersson, J. M.
    R&D Material and Technology Development, SECO Tools AB, SE-737 82 Fagersta, Sweden.
    Anglada, M. J.
    Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya, Campus Diagonal Besòs-EEBE, Barcelona, Spain / Centre for Research in Multiscale Engineering of Barcelona, Universitat Politècnica de Catalunya, Campus Diagonal Besòs-EEBE, Barcelona, Spain.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Enhanced thermal stability and fracture toughness of TiAlN coatings by Cr, Nb and V-alloying2018In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 342, p. 85-93Article in journal (Refereed)
    Abstract [en]

    The effect of metal alloying on mechanical properties including hardness and fracture toughness were investigated in three alloys, Ti 0.33Al0.50(Me) 0.17N (Me = Cr, Nb and V), and compared to Ti0.50Al0.50N, in the as-deposited state and after annealing. All studied alloys display similar as-deposited hardness while the hardness evolution during annealing is found to be connected to phase transformations, related to the alloy’s thermal stability. The most pronounced hardening was observed in Ti0.50Al0.50N, while all the coatings with additional metal elements sustain their hardness better and they are harder than Ti0.50Al0.50N after annealing at 1100 °C. Fracture toughness properties were extracted from scratch tests. In all tested conditions, as-deposited and annealed at 900 and 1100 °C, Ti0.33Al0.50Nb0.17N show the least surface and sub-surface damage when scratched despite the differences in decomposition behavior and h-AlN formation. Theoretically estimated ductility of phases existing in the coatings correlates well with their crack resistance. In summary, Ti0.33Al0.50Nb0.17N is the toughest alloy in both as-deposited and post-annealed states.

    The full text will be freely available from 2020-02-17 16:38
  • 6.
    Chen, Yu-Hsiang
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Rongström, L.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Ostach, D.
    HZG, Germany.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson-Jöesaar, Mats P
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Schell, N.
    HZG, Germany.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Effects of decomposition route and microstructure on h-AlN formation rate in TiCrAlN alloys2017In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 691, p. 1024-1032Article in journal (Refereed)
    Abstract [en]

    The phase evolution of cubic (c), solid solution TixCr-0.37Al1-0.37-x N alloys with x = 0.03 and 0.16, and the kinetics of the hexagonal (h)-AlN formation are studied via in situ wide angle x-ray scattering experiments during high temperature (1000-1150 degrees C) annealing. Spinodal decomposition was observed in Ti0.16Cr0.36Al0.48N while Ti0.03Cr0.38Al0.59N decomposes through nucleation and growth of h-AlN, c-TiN and c-CrAlN. h-AlN is formed from c-CrAlN domains in both cases and the formation rate of h-AlN depends on the stability of the c-CrAlN domains. In Ti0.16Cr0.36Al0.48N, the c-CrAlN domains are stabilized by crystallographic coherency with the surrounding c-TiCrN in a microstructure originating from spinodal decomposition. This results in lower formation rates of h-AlN for this composition. These differences are reflected in higher activation energy for h-AlN formation in Ti0.16Cr0.36Al0.48N compared to Ti0.03Cr0.38Al0.59N. It also points out different stabilities of the intermediate phase c-CrAlN during phase decomposition of TiCrAlN alloys. Additional contributions to the low activation energy for formation of h-AlN in Ti0.03Cr0.38Al0.59N stems from precipitation at grain boundaries. (C) 2016 Elsevier B.V. All rights reserved.

  • 7.
    Engberg, David L. J.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Johnson, Lars J. S.
    Sandvik Coromant, Stockholm, Sweden.
    Johansson-­‐Jöesaar, Mats
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Fagersta, Sweden.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Thuvander, Mattias
    Department of Applied Physics, Chalmers University of Technology, Göteborg, Sweden.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Solid Solution and Segregation Effects in Arc-Deposited Ti1-xSixN Thin Films Resolved on the nanometer scale by 15N Isotopic Substitution in AtomP robe TomographyManuscript (preprint) (Other academic)
    Abstract [en]

    Nanostructured TiSiN is an important material in wear--‐resistant coatings for extending the lifetime of cutting tools. Yet, the understanding regarding the structure, phase composition, and bonding on the detailed nanometer scale, which determines the properties of TiSiN, is lacking. This limits our understanding of the growth phenomena and eventually a larger exploitation of the material. By substituting natN2 with 15N2 during reactive arc deposition of TiSiN thin films, atom probe tomography (APT) gives elemental sensitivity and sub-nanometer resolution, a finer scale than what can be obtained by commonly employed energy dispersive electron spectroscopy in scanning transmission electron microscopy. Using a combination of analytical transmission electron microscopy and APT we show that arc-deposited Ti0.92Si0.0815N and Ti0.81Si0.1915N exhibit Si segregation on the nanometer scale in the alloy films. APT composition maps and proximity histograms from domains with higher than average Ti content show that the TiN domains contain at least ~2 at. % Si for Ti0.92Si0.08N and ~5 at. % Si for Ti0.81Si0.19N, thus confirming the formation of solid solutions. The formation of relatively pure SiNy domains in the Ti0.81Si0.19N films is tied to pockets between microstructured, columnar features in the film. Finer SiNy enrichments seen in APT possibly correspond to tissue layers around TiN crystallites, thus effectively hindering growth of TiN crystallites, causing TiN renucleation and thus explaining the featherlike nanostructure within the columns of these films. For the stoichiometry of the TiN phase, we establish a global under stoichiometry, in accordance with the tendency for SiNy films to have tetrahedral bonding coordination towards a nominal Si3N4 composition.

  • 8.
    Eriksson, Anders
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Näslund, Lars-Åke
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Sjölen, J.
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Arc deposition of Ti–Si–C–N thin films from binary and ternary cathodes — Comparing sources of C2012In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 213, p. 145-154Article in journal (Refereed)
    Abstract [en]

    Ti–Si–C–N thin films with composition of 1–11 at.% Si and 1–20 at.% C have been deposited onto cemented carbide substrates by arcing Ti–Si cathodes in a CH4 + N2 gas mixture and, alternatively, through arcing Ti–Si–C cathodes in N2. Films of comparable compositions from the two types of cathodes have similar structure and properties. Hence, C can be supplied as either plasma ions generated from the cathode or atoms from the gas phase with small influence on the structural evolution. Over the compositional range obtained, the films were dense and cubic-phase nanocrystalline, as characterized by X-ray diffraction, ion beam analysis, and scanning and transmission electron microscopy. The films have high hardness (30–40 GPa by nanoindentation) due to hardening from low-angle grain boundaries on the nanometer scale and lattice defects such as growth-induced vacancies and alloying element interstitials.

  • 9.
    Eriksson, Anders
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Zhu, Jianqiang
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools AB, Sweden.
    Sjölen, Jacob
    Seco Tools AB, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ti-Si-C-N Thin Films Grown by Reactive Arc Evaporation from Ti3SiC2 Cathodes2011In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 26, p. 874-881Article in journal (Refereed)
    Abstract [en]

    Ti-Si-C-N thin films were deposited onto WC-Co substrates by industrial scale arc evaporation from Ti3SiC2 compound cathodes in N2 gas. Microstructure and hardness were found to be highly dependent on the wide range of film compositions attained, comprising up to 12 at.% Si and 16 at.% C. Nonreactive deposition yielded films consisting of understoichiometric TiCx, Ti and silicide phases with high (27 GPa) hardness. At a nitrogen pressure of 0.25-0.5 Pa, below that required for N saturation, superhard, 45-50 GPa, (Ti,Si)(C,N) films with a nanocrystalline feathered structure were formed. Films grown above 2 Pa displayed crystalline phases of more pronounced nitride character, but with C and Si segregated to grain boundaries to form weak grain boundary phases. In abundance of N, the combined presence of Si and C disturb cubic phase growth severely and compromises the mechanical strength of the films.

  • 10.
    Eriksson, Anders
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Zhu, Jianqiang
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools AB, Sweden.
    Sjölen, Jacob
    Seco Tools AB, Sweden.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Layer Formation by Resputtering in Ti-Si-C Hard Coatings during Large Scale Cathodic Arc Deposition2011In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 205, no 15, p. 3923-3930Article in journal (Refereed)
    Abstract [en]

    This paper presents the physical mechanism behind the phenomenon of self-layering in thin films made by industrial scale cathodic arc deposition systems using compound cathodes and rotating substrate fixture. For Ti-Si-C films, electron microscopy and energy dispersive x-ray spectrometry reveals a trapezoid modulation in Si content in the substrate normal direction, with a period of 4 to 23 nm dependent on cathode configuration. This is caused by preferential resputtering of Si by the energetic deposition flux incident at high incidence angles when the substrates are facing away from the cathodes. The Ti-rich sub-layers exhibit TiC grains with size up to 5 nm, while layers with high Si-content are less crystalline. The nanoindentation hardness of the films increases with decreasing layer thickness.

  • 11.
    Fager, Hanna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Andersson, J. M.
    Seco Tools AB, SE-737 82 Fagersta, Sweden.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Growth of Hard Amorphous Ti-Al-Si-N Thin Films by Cathodic Arc Evaporation2013In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 235, no 25, p. 376-385Article in journal (Refereed)
    Abstract [en]

    Ti(1−x−y)AlxSiyNz (0.02≤x≤0.46, 0.02≤y≤0.28, and 1.08≤z≤1.29) thin films were grown on cemented carbide substrates in an industrial scale cathodic arc evaporation system using Ti-Al-Si compound cathodes in a N2 atmosphere. The microstructure of the as-deposited films changes from nanocrystalline to amorphous by addition of Al and Si to TiN. Upon incorporation of 12 at% Si and 18 at% Al, the films assume an x-ray amorphous state. Post-deposition anneals show that the films are thermally stable up to 900 ◦C. The films exhibit age hardening up to 1000 ◦C with an increase in hardness from 21.9 GPa for as-deposited films to 31.6 GPa at 1000 ◦C. At 1100 ◦C severe out-diffusion of Co and W from the substrate occur, and the films recrystallize into c-TiN and w-AlN.

  • 12.
    Forsén, Rikard
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Decomposition and phase transformation in TiCrAlN thin coatings2012In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 30, no 6Article in journal (Refereed)
    Abstract [en]

    Phase transformations and mechanisms that yield enhanced high temperature mechanical properties of metastable solid solutions of cubic (c)-(TixCryAlz)N coatings are discussed in this paper. Coatings grown by reactive arc evaporation technique with metal composition range y<17 at. % and 45<z<62 at. % are studied and compared with the parent TiAlN material system. The coatings exhibit age hardening up to 1000 ºC which is higher compared to what is observed for TiAlN. In addition, the coatings show a less pronounced hardness decrease when hexagonal (h)-AlN is formed compared to TiAlN. The improved thermal stability is discussed in terms of a lowered coherency stress and a lowered enthalpy of mixing due to the addition of Cr, which results in improved functionality in the working temperature range of 850-1000 ºC of for example cutting tools. Upon annealing up to 1400 ºC the coatings decompose into c-TiN, bcc-Cr and h-AlN. The decomposition takes place via several intermediate phases, c-CrAlN, c-TiCrN and hexagonal (β)-Cr2N. The microstructure  evolution investigated at different stages of spinodal decomposition and phase transformation is correlated to the thermal response and mechanical hardness of the coatings.

  • 13.
    Forsén, Rikard
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Improved mechanical properties in oxidation resistant AlCrN coatings through Ti additionManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    Quaternary cubic (c)-(TixCryAl~0.60)1N1 coatings with different x to y ratios have been grown using reactive cathodic arc evaporation. Results show that by adding Ti the high temperature mechanical properties are drastically improved with a retained hardness up to 1100 ºC. The coatings show an age hardening process caused by the formation of hexagonal (h)-AlN and cubic (c)-TiCrN precipitates surrounded by a TiCrAlN host matrix. The improved properties are discussed in terms of kinetics where the addition of Ti delays and suppresses the growth the h-AlN phase. The Ti atoms also generate incoherent crystallites within the h-AlN domains disrupting the hexagonal lattice during the coarsening process. Altogether the result is that the detrimental effects that are normally associated with the hexagonal phase are shifted to higher temperatures.

    The oxidation resistance is also investigated with different amount of Ti addition. The addition of Ti promotes the formation of a TiO2 oxide layer over Al2O3 resulting in a lower oxidation resistance. However, by tuning the composition it is possible to generate coatings having both high oxidation resistance and excellent high temperature mechanical properties.

  • 14.
    Hellgren, Niklas
    et al.
    Intel Corporation, Portland Technology Development, RA3-301, 5200 NE Elam Young Parkway, Hillsboro, OR 97124, USA.
    Berlind, Torun
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics. Linköping University, The Institute of Technology.
    Gueorguiev, Gueorgui K.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Johansson, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Stafström, Sven
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Fullerene-like B C N thin films a computational andexperimental study2004In: Materials Science and Engineering B, Vol. 113, no 3, p. 242-247Article in journal (Refereed)
    Abstract [en]

    Ab initio calculations show that the energy cost for incorporating lattice defects such as pentagons and heptagons is significantly reduced for BCN compared to BN, thus promoting bending of basal planes in these compounds. Boron–carbon–nitride (Bsingle bondCsingle bondN) thin films with a fullerene-like (FL) microstructure were then deposited by dual cathode magnetron sputtering from C and B4C targets. Up to 1 μm thick films were grown at a total gas pressure of 3 mTorr (0.4 Pa) in varying Ar/N2 ratios, and substrate temperatures between 225 and 350 °C. Compositional and microstructural studies were performed using RBS, SEM and HREM, respectively. Depending on the deposition condition, ternary BxCyNz films with fullerene-like microstructure could be prepared in agreement with the calculations within the composition range 0 ≤ x ≤ 53, 15 ≤ y ≤ 62, and 24 ≤ z ≤ 50 at.%. Fullerene-like structures also tend to form at lower temperatures in the case of BCN compared to CN. Nanoindentation measurements show that all BxCyNz films exhibited a highly elastic response independent of elemental composition. In addition, the calculations suggest a driving force for C and BN phase separation.

  • 15.
    Johansson Jöesaar, Mats P.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools AB, Fagersta, Sweden.
    Norrby, Niklas
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ullbrand, Jennifer
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Saoubi, R.
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Anisotropy effects onmicrostructure and properties in decomposed arc evaporated Ti1-xAlxN coatings during metal cutting2013In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 235, no 25, p. 181-185Article in journal (Refereed)
    Abstract [en]

    Anisotropy effects on the spinodal decomposition in cathodic arc evaporated cubic “phase c-Ti1−xAlxN coatingshave been studied with respect to composition, microstructure and hardness properties before and after a continuousturning operation. Coatings are simultaneously being exposed to both a high temperature and high pressureduring the metal cutting process. As evident from the current results, a high Al content coating, x = 0.66,when exposed to such extreme conditions decomposes into cubic c-AlN and c-TiN-rich domains. In this case,the evolving microstructure comprises interconnected spatially periodic, elongated and coherent cubic c-AlNand c-TiN-rich regions aligned along elastic compliant b100N crystal direction. A significantly different microstructurewith randomly oriented domains is observed for a coating with an elemental composition closer tothe isotropic limit, x = 0.28, exposed under the same conditions. From a coating hardness perspective, thenanoindentation results display a minor age hardening effect for the c-Ti1−xAlxN coating grown at x = 0.28while the coating grown with x = 0.66 exhibits a significant age-hardening effect of about 18%. We concludethat both microstructure and age hardening behavior during spinodal decomposition of c-Ti1−xAlxN correlateto the relative amount ofmetal Ti/Al ratio and consequently to the elastic anisotropy of the as-grown coatingmaterial.These results provide newinsights to the understanding of improvedwear resistance of c-Ti1−xAlxN withAl content during metal cutting.

  • 16.
    Johansson, Mats
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Broitman, Esteban
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hellgren, Niklas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sundgren, Jan-Eric
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    High Resolution Electron Microscopy Studies of Magnetron Sputtered Leek-Like CNx Films1998In: Electron Microscopy 1998 Volume III Materials Science 2 / [ed] Héctor A. Calderón Benavides, M. José Yacamán, Taylor & Francis, 1998, p. 89-90Conference paper (Refereed)
    Abstract [en]

    After the discovery of C fullerenes and later C nanotubes, nanostructures made out of C and B in combination with N have become of increasing interest due to their possible use in mechanical applications, e.g., as hard coatings as well as in nanoelectronics, e.g., for flat panel displays Still, however, no conclusive evidence of the formation of either closed cages or tubules made of carbon nitride CNx have been reported. Here we report on the formation of CNx, (0 < x < 0.33) fullerene-like structures in the form of tubular arrangements (leek-like) from curved CN basal planes with the c-axis in the substrate plane.

  • 17.
    Johansson, Mats
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Norrby, Niklas
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ullbrand, Jennifer
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    M’Saoubi, Rachid
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnsu
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Microstructural anisotropy effects on the metal cutting performance of decomposed arc evaporated Ti1-xAlxN coatingsManuscript (preprint) (Other academic)
    Abstract [en]

    The spinodal decomposition of cathodic arc evaporated cubic phase c-Ti0.34Al0.66N and c-Ti0.60Al0.40N coatings have been studied before and after continuous turning. By means of analytical transmission electron microscopy, we find that the evolving microstructure of c-Ti0.34Al0.66N, as simultaneously being exposed to high temperature of about 900 °C and high pressure of about 2.5 GPa, spinodally decompose into a spatially periodic, highly oriented and modulated interconnected array of coherent cubic AlN and cubic TiN rich regions along elastic compliant <100> crystal directions. Ti0.60Al0.40N instead decomposes into AlN and TiN rich domains in a more rounded and random microstructure. These effects are both explained by the elastic anisotropy which has earlier been shown to scale with Al content. The different evolving microstructure will lead to a different strengthening mechanism in the coatings during metal cutting and heat treatments, thus a different hardness and wear resistance behaviour.

  • 18.
    Johansson, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Growth and microstructure of reactive sputter deposited boron nitride: carbon (BN:C) thin films1995Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Growth, microstructure and mechanical properties of boron nitride: carbon (BN:C) have been studied in films prepared by reactive r.f. diode sputter deposition as well as by reactive unbalanced d.c. magnetron (UBM) sputter deposition of low resistivity boron carbide (B4C) targets. Due to the fäet that d.c. glow discharges offers a better control of the important growth parameters such as particle flux and energy distribution in both neutral and ionized states at the substrate as compared to r.f. methods, fundamental growth and plasma studies were in some detail performed in the UBM sputtering system.

    Films were prepared with three characteristic phase compositions; cubic c-BN:C, hexagonal (turbostratic-like) h-BN:C and a mixtures of these on Si (001) substrates. The same phase compositions were obtained in both deposition techniques. While keeping the B/N ratio close to unity, the formation of BN:C phases were mainly correlated to the energy and flux of impinging ions towards the negatively d.c. biased substrate. A c-BN:C phase formation was typically found in mixed c-BN:C and h-BN:C films prepared at high ion-to-neutral flux ratios (UBM: Ji/Jn ~24), within a narrow range in ion energies (UBM: 85 eV < Ei < 135 eV) and at low process temperatures <250 °C. However, almost single phase c-BN:C (~80 % of sp3-bonded B-N) was obtained at deposition conditions of high ion flux (UBM: Ji/Jn ~24) and low ion energy (UBM: Ei = 110 eV) whereas films deposited at much lower ion energy or at a lower ion fluxes contained exclusively h-BN:C. Also, c-BN:C films revealed a BN:C film phase evolution sequence from an initial amorphous BN:C layer followed by a highly oriented h-BN:C layer with the c-axis parallel to the film surface, to a c-BN:C layer exhibiting a (110)­preferred orientation. Furthermore, as-deposited films contained 5 - 20 at% of C that was found to decrease with increasing volume fraction of c-BN:C and also with increasing J/Jn. Chemical sputtering of volatile CN species is suggested for the reduction of C in BN:C films. Nevertheless, the C in c-BN:C films is mainly present as C-C and B-C bonds.

    Unnoticed the presence of C, cubic phase BN:C films are shown to be formed at deposition conditions not included in the present models of c-BN growth. For example, in terms of momentum transfer, values of 200 - 250 (eV emu)% have been reported to be required for the synthesis of c-BN whereas in this study an order of magnitude higher values were found. The results thus point at an extended deposition window for cubic phase formation, with potential for using further reduced ion energies such that intrinsic compressive stress in BN can be minimized.

    Finally, the mechanical properties of randomly- and highly-oriented h-BN:C as well as of c-BN:C films were studied and compared to the uncoated Si substrate. Although all coated substrates showed an increased stiffness, the maybe most interesting properties were found in the highly oriented h-BN:C films with the c-axis parallel to the film surface. These films showed a predominantly elastic behaviour exhibiting an elastic recovery as high as 82% indicating high hardness values. The improved hardness and elasticity may be explained by the apparent microstructure with buckling of the hexagonal basal planes. This structure is proposed to correspond to a three dimensional strongly covalently bonded network of BN:C, similar to what has been reported for CNx films.

  • 19.
    Johnson, Lars
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Microstructure evolution and age hardening in (Ti,Si)(C,N) thin films deposited by cathodic arc evaporation2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, no 4, p. 1397-1403Article in journal (Refereed)
    Abstract [en]

    Ti1 − xSixCyN1 − y films have been deposited by reactive cathodic arc evaporation onto cemented    carbide substrates. The films were characterized by X-ray diffraction, elastic recoil detection analysis, transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron-energy loss spectroscopy and nanoindentation. Reactive arc evaporation in a mixed CH4 and N2 gas gave    films with 0 ≤ x ≤ 0.13 and 0≤y≤0.27. All films had the NaCl-structure with a dense columnar microstructure, containing a featherlike pattern of nanocrystalline grains for high Si and C contents. The film hardness was 32–40GPa. Films with x > 0 and y > 0 exhibited age-hardening up to 35–44 GPa when isothermally annealed up to 900 °C. The temperature threshold for over-ageing was decreased to 700 °C with increasing C and Si content, due to migration of Co, W and Cr from the substrate to the film, and loss of Si. The diffusion pathway was tied to grain boundaries provided by the featherlike substructure.

  • 20.
    Knutsson, Axel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Karlsson, L
    Seco Tools AB.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Thermally enhanced mechanical properties of arc evaporated Ti0.34Al0.66N/TiN multilayer coatings2010In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, no 4, p. 044312-Article in journal (Refereed)
    Abstract [en]

    Cubic metastable Ti0.34Al0.66N/TiN multilayer coatings of three different periods, 25+50, 12+25, and 6+12 nm, and monoliths of Ti0.34Al0.66N and TiN where grown by reactive arc evaporation. Differential scanning calorimetry reveals that the isostructural spinodal decomposition to AlN and TiN in the multilayers starts at a lower temperature compared to the monolithic TiAlN, while the subsequent transformation from c-AlN to h-AlN is delayed to higher temperatures. Mechanical testing by nanoindentation reveals that, despite the 60 vol % TiN, the as-deposited multilayers show similar or slightly higher hardness than the monolithic Ti0.34Al0.66N. In addition, the multilayers show a more pronounced age hardening compared to the monolith. The enhanced hardening phenomena and improved thermal stability of the multilayer coatings are discussed in terms of particle confinement and coherency stresses from the neighboring TiN-layers.

  • 21.
    Knutsson, Axel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ullbrand, Jennifer
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Norrby, Niklas
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Almer, Jonathan
    Argonne National Laboratory, Illinois, USA.
    Johansson, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Jansson, Bo
    Seco Tools AB, Fagersta, Sweden.
    Magnus, Odén
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Early stage spinodal decomposition and microstructure evolution in TiAlN: A combined in-situ SAXS and phase field studyManuscript (preprint) (Other academic)
    Abstract [en]

    This paper describes in detail the microstructure and phase evolution in Ti0.33Al0.67N and Ti0.50Al0.50N coatings during isothermal annealing, studied by in-situ small angle x-ray scattering (SAXS), in combination with phase field simulations. We show that the isostructural spinodal decomposition occurs in two stages. During the initial stage, the phase segregation proceeds with a constant size of AlN- and TiN-rich domains with an experimentally measured radius of ~0.7 nm for 5 and 20 min at 900 and 850 °C respectively in the Ti0.50Al0.50N alloy. The length of  the initial stage depends on temperature as well as metal composition, and is shorter for the higher Al-content  coating. After the initial stage, the coherent cubic AlN- and TiN-rich domains coarsen. The coarsening process is kinetically limited by diffusion, which allowed us to estimate the diffusivity and activation energies of the metals to 1.4·10-7 m2s-1 and 3.14 eV at-1 respectively.

  • 22.
    Knutsson, Axel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ullbrand, Jennifer
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Norrby, Niklas
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johnson, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Almer, J.
    Advanced Photon Source, Argonne National Laboratory, Argonne, USA.
    Johansson, M.P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools AB, Fagersta, Sweden.
    Jansson, B.
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Microstructure evolution during the isostructural decomposition of TiAlN: a combined in-situ small angle x-ray scattering and phase field study2013In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, no 21Article in journal (Refereed)
    Abstract [en]

    This paper describes details of the spinodal decomposition and coarsening in metastable cubic Ti0.33Al0.67N and Ti0.50Al0.50N coatings during isothermal annealing, studied by in-situ small angle x-ray scattering, in combination with phase field simulations. We show that the isostructural decomposition occurs in two stages. During the initial stage, spinodal decomposition, of the Ti0.50Al0.50N alloy, the phase separation proceeds with a constant compositional wavelength of ∼2.8 nm of the AlN- and TiN-rich domains. The time for spinodal decomposition depends on annealing temperature as well as alloy composition. After the spinodal decomposition, the coherent cubic AlN- and TiN-rich domains coarsen. The coarsening rate is kinetically limited by diffusion, which allowed us to estimate the diffusivity and activation energy of the metals to 1.4 × 10−6 m2 s−1 and 3.14 eV at−1, respectively.

  • 23.
    Landälv, Ludvig
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Sandvik Coromant AB, Sweden.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Spitz, S.
    Karlsruhe Institute Technology, Germany.
    Leiste, H.
    Karlsruhe Institute Technology, Germany.
    Ulrich, S.
    Karlsruhe Institute Technology, Germany.
    Johansson-Jöesaar, Mats P
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Ahlgren, M.
    Sandvik Coromant AB, Sweden.
    Gothelid, E.
    Sandvik Coromant AB, Sweden.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Max Planck Institute Eisenforsch GmbH, Germany.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Stueber, M.
    Karlsruhe Institute Technology, Germany.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Structural evolution in reactive RF magnetron sputtered (Cr,Zr)2O3 coatings during annealing2017In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 131, p. 543-552Article in journal (Refereed)
    Abstract [en]

    Reactive RF-magnetron sputtering is used to grow Cr0.28Zr0.10O0.61 coatings at 500 degrees C. Coatings are annealed at 750 degrees C, 810 degrees C, and 870 degrees C. The microstructure evolution of the pseudobinary oxide compound is characterized through high resolution state of the art HRSTEM and HREDX-maps, revealing the segregation of Cr and Zr on the nm scale. The as-deposited coating comprises cc-(Cr,Zr)(2)O-3 solid solution with a Zr-rich (Zr,Cr)O-x. amorphous phase. After annealing to 750 degrees C tetragonal ZrO2 nucleates and grows from the amorphous phase. The ZrO2 phase is stabilized in its tetragonal structure at these fairly low annealing temperatures, possibly due to the small grain size (below 30 nm). Correlated with the nucleation and growth of the tetragonal-ZrO2 phase is an increase in hardness, with a maximum hardness after annealing to 750 degrees C, followed by a decrease in hardness upon coarsening, bcc metallic Cr phase formation and loss of oxygen, during annealing to 870 degrees C. The observed phase segregation opens up future design routes for pseudobinary oxides with tunable microstructural and mechanical properties. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 24.
    Lind, Hans
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Forsén, Rikard
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Tasnadi, Ferenc
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Johansson, M P
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Abrikosov, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Improving thermal stability of hard coating films via a concept of multicomponent alloying2011In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 99, no 9, p. 091903-Article in journal (Refereed)
    Abstract [en]

    We propose a design route for the next generation of nitride alloys via a concept of multicomponent alloying based on self-organization on the nanoscale via a formation of metastable intermediate products during the spinodal decomposition. We predict theoretically and demonstrate experimentally that quasi-ternary (TiCrAl)N alloys decompose spinodally into (TiCr)N and (CrAl)N-rich nanometer sized regions. The spinodal decomposition results in age hardening, while the presence of Cr within the AlN phase delays the formation of a detrimental wurtzite phase leading to a substantial improvement of thermal stability compared to the quasi-binary (TiAl)N or (CrAl)N alloys.

  • 25.
    Lind, Hans
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Pilemalm, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Tasnadi, Ferenc
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Forsén, Rikard
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johnson, Lars
    Sandvik Coromant, Stockholm, Sweden.
    Jöesaar, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. SECO Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Abrikosov, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    High temperature phase decomposition in TixZryAlzN2014In: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 4, no 12, p. 127147-1-127147-9Article in journal (Refereed)
    Abstract [en]

    Through a combination of theoretical and experimental observations we study the high temperature decomposition behavior of c-(TixZryAlzN) alloys. We show that for most concentrations the high formation energy of (ZrAl)N causes a strong tendency for spinodal decomposition between ZrN and AlN while other decompositions tendencies are suppressed. In addition we observe that entropic  effects due to configurational disorder favor a formation of a stable Zr-rich (TiZr)N phase with increasing temperature. Our calculations also predict that at high temperatures a Zr rich (TiZrAl)N disordered phase should become more resistant against the spinodal decomposition despite its high and positive formation energy due to the specific topology of the free energy surface at the relevant concentrations. Our experimental observations confirm this prediction by showing strong tendency towards decomposition in a Zr-poor sample while a Zr-rich alloy shows a greatly reduced decomposition rate, which is mostly attributable to binodal decomposition processes. This result highlights the importance of considering the second derivative of the free energy, in addition to its absolute value in predicting decomposition trends of thermodynamically unstable alloys.

  • 26.
    Norrby, Niklas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Improved metal cutting performance with biasmodulated textured Ti0.50Al0.50N multilayers2014In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 257, p. 102-107Article in journal (Refereed)
    Abstract [en]

    In this work we present the cutting performance of Ti0.50Al0.50N coatings which have been deposited with both a fixed and an alternating bias of -35 V and -70 V together with a Ti0.33Al0.67N reference coating grown at -35 V. The bias-modulated coatings were grown with different bias-layer periods, from 200 to 1200 nm. For the layers deposited with a fixed bias, a transition from a (100) to a (111) preferred orientation was observed with the change in bias from -35 V to -70 V. The coatings grown with an alternating bias, however, showed a (111) preferred orientation with an intensity that slightly depends on bias-layer period. Metal cutting performance in terms of crater and flank wear resistance show an improvement for all bias-layered coatings. This is attributed to a (111) oriented refined grain structure in combination with low residual stresses in the coating.

  • 27.
    Norrby, Niklas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    M’Saoubi, Rachid
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Pressure and temperature effects on the decomposition of arc evaporated Ti0.6Al0.4N coatings during metal cutting2012In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 209, p. 203-207Article in journal (Refereed)
    Abstract [en]

    The isostructural decomposition of arc evaporated Ti0.6Al0.4N coatings at the elevated temperatures and high stresses occurring during metal cutting have been studied. Comparisons are made with short time (t=10 min) anneals at temperatures typical for steel turning operations. The evolution of the decomposed domain sizes are studied by analytical transmission electron microscopy from samples originating from the rake face. Temperature and force measurements during turning allowed for separation of the effects of the temperature and stresses on domain size evolution. The results show a peak temperature of around 900 °C and a peak normal stress of around 2 GPa during cutting. The overall domain size is larger after cutting compared to the annealed sample at the same temperature. The results suggest that pressures generated during cutting promote coherent isostructural decomposition which is in line with theoretical studies but for considerably higher pressures.

  • 28.
    Norrby, Niklas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Lind, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Parakhonskiy, G
    University of Bayreuth, Germany .
    Johansson, M P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Tasnadi, Ferenc
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Dubrovinsky, L S.
    University of Bayreuth, Germany .
    Dubrovinskaia, N
    University of Bayreuth, Germany .
    Abrikosov, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    High pressure and high temperature stabilization of cubic AlN in Ti0.60Al0.40N2013In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, no 5Article in journal (Refereed)
    Abstract [en]

    In the present work, the decomposition of unstable arc evaporated Ti0.6Al0.4N at elevated temperatures and quasihydrostatic pressures has been studied both experimentally and by first-principles calculations. High pressure and high temperature (HPHT) treatment of the samples was realized using the multi anvil press and diamond anvil cell techniques. The products of the HPHT treatment of Ti0.6Al0.4N were investigated using x-ray diffractometry and transmission electron microscopy. Complimentary calculations show that both hydrostatic pressure and high temperature stabilize the cubic phase of AlN, which is one of the decomposition products of Ti0.6Al0.4N. This is in agreement with the experimental results which in addition suggest that the presence of Ti in the system serves to increase the stability region of the cubic c-AlN phase. The results are industrially important as they show that Ti0.6Al0.4N coatings on cutting inserts do not deteriorate faster under pressure due to the cubic AlN to hexagonal AlN transformation.

  • 29.
    Norrby, Niklas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools AB, Fagersta, Sweden.
    Schell, N.
    Helmholtz-Zentrum Geesthacht (HZG), Geesthacht, Germany.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    In-situ x-ray scattering study of the cubic to hexagonal transformation of AlN in Ti1-xAlxN2014In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 73, p. 205-214Article in journal (Refereed)
    Abstract [en]

    In the present work, we have studied the decomposition of arc evaporated Ti0.55Al0.45N and Ti0.36Al0.64N during heat treatment in vacuum by in-situ synchrotron wide angle x-ray scattering primarily to characterize the kinetics of the phase transformation of AlN from the cubic NaCl-structure to the hexagonal wurtzite-structure. In addition, in-situ small angle x-ray scattering measurements were conducted to explore details of the wavelength evolution of the spinodal decomposition, thus providing information about the critical size of the c-AlN rich domains prior to the onset of the h-AlN transformation. We report the fractional cubic to hexagonal transformation of AlN in Ti1-xAlxN as a function of time and extract activation energies between 320 and 350 kJ/mol dependent on alloy composition. The onset of the hexagonal transformation occurs at about 50 K lower temperature in Ti0.36Al0.64N compared to Ti0.55Al0.45N where the high Al content alloy also has a significantly higher transformation rate. A critical wavelength for the cubic domains of about 13 nm was observed for both alloys. Scanning transmission electron microscopy shows a c-TiN/h-AlN microstructure with a striking morphology resemblance to the c-TiN/c-AlN microstructure present prior to the hexagonal transformation.

  • 30.
    Rogström, Lina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools AB, 737 82 Fagersta, Sweden.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Influence of chemical composition and deposition conditions on microstructure evolution during annealing of arc evaporated ZrAlN thin films2012In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 30, no 3, p. 031504-Article in journal (Refereed)
    Abstract [en]

    The influence of substrate bias and chemical composition on the microstructure and hardness of arc evaporated Zr1−xAlxN films with 0.12 < x < 0.74 is investigated. A cubic ZrAlN phase is formed at low aluminum contents (x < 0.38) whereas for a high Al-content, above x=0.70, a single-phase hexagonal structure is obtained. For intermediate Al-contents, a two-phase structure is formed. The cubic structured films exhibit higher hardness than the hexagonal structured ones. A low bias results in N-rich films with a partly defect-rich microstructure while a higher substrate bias decreases the grain size and increases the residual stress in the cubic ZrAlN films. Recrystallization and out-diffusion of nitrogen from the lattice in the cubic ZrAlN films takes place during annealing at 800 C, which results in an increased hardness. The cubic ZrAlN phase is stable to annealing temperatures of 1000 C while annealing at higher temperature results in nucleation and growth of hexagonal AlN. In the high Al-content ZrAlN films, formation of ZrN- and AlN-rich domains within the hexagonal lattice during annealing at 1000 C improves the mechanical properties.

  • 31.
    Rogström, Lina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson, Mats P.
    Seco Tools AB, Sweden.
    Pilemalm, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Johnson, L. J. S.
    Sandvik Coromant, Sweden.
    Schell, N.
    Helmholtz Zentrum Geesthacht, Germany.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Decomposition routes and strain evolution in arc deposited TiZrAlN coatings2019In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 779, p. 261-269Article in journal (Refereed)
    Abstract [en]

    Phase, microstructure, and strain evolution during annealing of arc deposited TiZrAlN coatings are studied using in situ x-ray scattering and ex situ transmission electron microscopy. We find that the decomposition route changes from nucleation and growth of wurtzite AlN to spinodal decomposition when the Zr-content is decreased and the Al-content increases. Decomposition of Ti0.31Zr0.24Al0.45N results in homogeneously distributed wurtzite AlN grains in a cubic, dislocation-dense matrix of TiZrN consisting of domains of different chemical composition. The combination of high dislocation density, variation of chemical composition within the cubic grains, and evenly distributed wurtzite AlN grains results in high compressive strains, -1.1%, which are retained after 3 h at 1100 degrees C. In coatings with higher Zr-content, the strains relax during annealing above 900 degrees C due to grain growth and defect annihilation. (C) 2018 Elsevier B.V. All rights reserved.

    The full text will be freely available from 2020-11-14 12:11
  • 32.
    Rogström, Lina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson-Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Landälv, Ludvig
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Sandvik Coromant, Sweden.
    Ahlgren, M.
    Sandvik Coromant, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Wear behavior of ZrAlN coated cutting tools during turning2015In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 282, p. 180-187Article in journal (Refereed)
    Abstract [en]

    In this study we explore the cutting performance of ZrAlN coatings. WC:Co cutting inserts coated by cathodic arc evaporated Zr1-xAlxN coatings with x between 0 and 0.83 were testeciin a longitudinal turning operation. The progress of wear was studied by optical microscopy and the used inserts were studied by electron microscopy. The cutting performance was correlated to the coating composition and the best performance was found for the coating with highest Al-content consisting of a wurtzite ZrAlN phase which is assigned to its high thermal stability. Material from the work piece was observed to adhere to the inserts during turning and the amount of adhered material and its chemical composition is independent on the Al-content of the coating. (C) 2015 Elsevier B.V. All rights reserved.

  • 33.
    Schramm, Isabella C.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Pauly, C.
    Functional Materials, Department Materials Science, Saarland University, Saarbrucken, Germany.
    Johansson Jõesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Fagersta, Sweden.
    Slawik, S.
    Functional Materials, Department Materials Science, Saarland University, Saarbrucken, Germany.
    Suarez, S.
    Functional Materials, Department Materials Science, Saarland University, Saarbrucken, Germany.
    Mücklich, F.
    Functional Materials, Department Materials Science, Saarland University, Saarbrucken, Germany.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Effects of nitrogen vacancies on phase stability and mechanical properties of arc deposited (Ti0.52Al0.48)Ny (y<1) coatings2017In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 330, no Supplement C, p. 77-86Article in journal (Refereed)
    Abstract [en]

    Nitrogen sub-stoichiometric (Ti0.52Al0.48)Ny (0.92 ≥ y  ≥ 0.46) coatings were grown in a mixed Ar/N2 atmosphere by cathodic arc deposition on cemented carbide (WC/Co-based) substrates. The coatings present a columnar structure with decreasing column widths from 250 to 60nm, due to a corresponding reduced N content, accompanied by changes in preferred orientation from 200 to 111 to 220. Among these, coatings prepared with 0.92≥y≥0.75 exhibit spinodal decomposition and consequently age hardening at elevated temperatures. A reduced N content upshifts the hardness maximum by >300 °C. For these samples, the high temperature treatment resulted in interdiffusion of substrate elements, Co and C, mainly along column boundaries. Nevertheless, no detrimental effect in the hardness could be correlated. Conversely, a low N content sample (y=0.46) presents significant lattice diffusion of substrate elements Co, C, W, and Ta in the coating. In this case, the substrate elements are present throughout the coating, forming additional phases such as c-Ti(C,N), c-Co(Al,Ti,W), and c-(Ti,W,Ta)(C,N), with an observed increased hardness from 16 to 25GPa. We suggest that the substitution of nitrogen by carbon and the solution of W and Ta in c-TiN are responsible for the observed hardening. Our investigation shows the potential of sub-stoichiometric (Ti1-xAlx)Ny coatings for high temperature applications such as cutting tools and puts forth corresponding criteria for N content selection.

  • 34.
    Schramm, Isabella
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. University of Saarland, Germany.
    Johansson Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Muecklich, F.
    University of Saarland, Germany.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Impact of nitrogen vacancies on the high temperature behavior of (Ti1-xAlx)N-y alloys2016In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 119, p. 218-228Article in journal (Refereed)
    Abstract [en]

    Substoichiometric solid solution alloys of cubic (Ti1-xAlx)N-y with x = 0.26, 0.48 and 0.60, and y ranging from 0.93 to 0.75 were grown by cathodic arc deposition. The influence of nitrogen deficiency on their thermal stability was studied by X-ray diffractometry, differential scanning calorimetry, scanning electron microscopy, and atom probe tomography. The nitrogen deficiency did not significantly affect the columnar growth nor the as deposited hardness. At elevated temperatures, alloys with x = 0.48 and 0.60 decompose isostructurally into cubic c-TiN and cubic c-AlN domains, which is consistent with spinodal decomposition. The decomposition is retarded by decreasing the nitrogen content, e.g. the formed isostructural domains in (Ti0.52Al0.48)N-0.92 at 900 degrees C are similar in size to (Ti0.52Al0.48)N-0.75 at 1200 degrees C. The formation of hexagonal w-AlN is shifted to higher temperatures by decreasing nitrogen content. Nucleation and growth of Al-Ti clusters in a Ti rich matrix were observed for the alloys with high Ti content, x = 0.26. These results suggest that nitrogen deficiency reduces the driving force for phase separation. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 35.
    Schramm, Isabella
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Saarland University, Germany.
    Pauly, C.
    Saarland University, Germany.
    Johansson Jöesaar, Mats P
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schmauch, J.
    Saarland University, Germany.
    Muecklich, F.
    Saarland University, Germany.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Solid state formation of Ti4AlN3 in cathodic arc deposited (Ti1-xAlx)N-y alloys2017In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 129, p. 268-277Article in journal (Refereed)
    Abstract [en]

    Reactive cathodic arc deposition was used to grow substoichiometric solid solution cubic c-(Ti1-xAlx)N-y thin films. The films were removed from the substrate and then heated in an argon environment to 1400 degrees C. Via solid state reactions, formation of MAX phase Ti4AlN3 was obtained. Additional phases such as Ti2AlN, c-TiN, w-AIN, Al5Ti2 and Al3Ti were also present during the solid state reaction. Ti4AlN3 formation was observed in samples with an Al metal fraction x amp;lt; 0.63 and a nitrogen content 0.4 amp;lt; y amp;lt; 0.6. Regardless of the initial composition, formation of Ti4AlN3 started in Ti2AlN crystal plates in the temperature range between 1200 and 1400 degrees C. Accompanying the onset of Ti4AlN3 was the presence of an intermediate structure identified as Ti6Al2N4, consisting of alternating layers of intergrown Ti2AlN and Ti4AlN3 phases with a half-unit-cell stacking. We suggest that the formation of Ti4AlN3 occurred via intercalation of aluminum and nitrogen along the basal plane accompanied by a simultaneous detwinning process. In addition we propose that this formation mechanism can be used to obtain MAX phases of high n order. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 36.
    Schroeder, Jeremy
    et al.
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Thomson, W.
    PVD Prod Inc, MA 01887 USA.
    Howard, B.
    PVD Prod Inc, MA 01887 USA.
    Schell, N.
    Helmholtz Zentrum Geesthacht, Germany.
    Näslund, Lars-Åke
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson-Jöesaar, Mats P.
    Seco Tools AB, Sweden.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Nothnagel, E.
    PVD Prod Inc, MA 01887 USA.
    Shepard, A.
    PVD Prod Inc, MA 01887 USA.
    Greer, J.
    PVD Prod Inc, MA 01887 USA.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation2015In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 86, no 9, p. 095113-Article in journal (Refereed)
    Abstract [en]

    We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (greater than50 keV), high photon flux (greater than10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (less than1 s) two-dimensional (2D) detector, permits time-resolved in situ structural analysis of thin film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (less than11 degrees), allowing large areas of reciprocal space to be imaged with a 2D detector. The system has been designed for use on the 1-tonne, ultra-high load, high-resolution hexapod at the P07 High Energy Materials Science beamline at PETRA III at the Deutsches Elektronen-Synchrotron in Hamburg, Germany. The deposition system includes standard features of a typical UHV deposition system plus a range of special features suited for synchrotron radiation studies and industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument. (C) 2015 AIP Publishing LLC.

  • 37.
    Syed, Bilal
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Linköping University.
    Jöessar, Mats J.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Fagersta, Sweden.
    Polcik, Peter
    PLANSEE Composite Materials GmbH, Lechbruck am See, Germany.
    Kolozsvari, Szilard
    PLANSEE Composite Materials GmbH, Lechbruck am See, Germany.
    Håkansson, Greger
    Ionbond Sweden AB, Box 1161, Linköping, Sweden.
    Johnson, Lars
    Sandvik Coromant, Stockholm, Sweden.
    Ahlgren, Mats
    Sandvik Coromant, Stockholm, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Effect of work function and cohesive energy of the constituent phases of Ti-50 at.% Al cathode during arc deposition of Ti-Al-N coatings2019In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 357, p. 393-401Article in journal (Refereed)
    Abstract [en]

    The differences in work function (W.F.) and cohesive energy (C.E.) of the phases constituting the cathode, plays an important role in the formation of the converted layer at its near-surface region during cathodic arc deposition. As a consequence, this also affects the deposition conditions for the coatings. In this study, we explore the effect of W.F. and C.E. of the constituent phases during arc evaporation by utilizing two kinds of customized Ti-50 at.% Al cathodes with different phase compositions. Our results show that during reactive arc evaporation the disparity in W.F. and C.E. among the constituent phases of Ti-50 at.% Al cathodes leads to preferential erosion of the phases with lower W.F. and C.E. The aforementioned preferential erosion begets higher surface roughness on the Ti-50 at.% Al cathode with a wider range of W.F. and C.E. disparity. It is also observed that the thermal conductivity of the Ti-50 at.% Al cathode plays a dominant role in the deposition rate of Ti-Al-N coating. This article also presents how the surface geometry of the cathode in the presence of arc guiding magnetic field significantly influences the microstructure of the deposited coatings.

    The full text will be freely available from 2020-10-15 12:50
  • 38.
    Syed, Bilal
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Zhu, Jianqiang
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Polcik, Peter
    PLANSEE Composite Materials GmbH, Germany.
    Kolozsvari, Szilard
    PLANSEE Composite Materials GmbH, Germany.
    Håkansson, Greger
    Ionbond Sweden AB, Sweden.
    Johnson, Lars
    Sandvik Coromant, Stockholm, Sweden.
    Ahlgren, Mats
    Sandvik Coromant, Stockholm, Sweden.
    Jöessar, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Morphology and microstructure evolution of Ti-50 at.% Al cathodes during cathodic arc deposition of Ti-Al-N coatings2017In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, no 24, article id 245309 (2017)Article in journal (Refereed)
    Abstract [en]

    Today's research on the cathodic arc deposition technique and coatings therefrom primarily focuses on the effects of, e.g., nitrogen partial pressure, growth temperature, and substrate bias. Detailed studies on the morphology and structure of the starting material—the cathode—during film growth and its influence on coating properties at different process conditions are rare. This work aims to study the evolution of the converted layer, its morphology, and microstructure, as a function of the cathode material grain size during deposition of Ti-Al-N coatings. The coatings were reactively grown in pure N2discharges from powder metallurgically manufactured Ti-50 at.% Al cathodes with grain size distribution averages close to 1800, 100, 50, and 10 μm, respectively, and characterized with respect to microstructure, composition, and mechanical properties. The results indicate that for the cathode of 1800 μm grain size the disparity in the work function among parent phases plays a dominant role in the pronounced erosion of Al, which yields the coatings rich in macro-particles and of high Al content. We further observed that a reduction in the grain size of Ti-50 at.% Al cathodes to 10 μm provides favorable conditions for self-sustaining reactions between Ti and Al phases upon arcing to form γ phase. The combination of self-sustaining reaction and the arc process not only result in the formation of hole-like and sub-hole features on the converted layer but also generate coatings of high Al content and laden with macro-particles.

  • 39.
    Tasnadi, Ferenc
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Natl Univ Sci and Technol MISIS, Russia.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Zhu, Jianqiang
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Wang, Fei
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Hsu, Tun-Wei
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Lind, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Abrikosov, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Natl Univ Sci and Technol MISIS, Russia.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    High temperature thermodynamics of spinodal decomposition in arc deposited TixNbyAlzN coatings2018In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 150, p. 165-170Article in journal (Refereed)
    Abstract [en]

    Using first principles calculations and experimental methods we show that B1 structured solid solution TixNbyAlzN can be grown. The mixing free energy surface indicates that the alloys should decompose. Theoretical analysis of the thermodynamic driving force towards the spinodal decomposition shows that the force can be different in alloys with equally low thermodynamic stability but different Nb content, indicating that the detailed picture of the decomposition should also be different. Electron microscopy and nanoindentation underlines different age hardening of the samples. We demonstrate that an alloy with the optimized composition, Ti0.42Nb0.17Al0.41N combines high thermal stability and age hardening behavior.

  • 40.
    Yalamanchili, K.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Wang, Fei
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Saarland University, Germany.
    Schramm, Isabella
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Saarland University, Germany.
    Andersson, J. M.
    Seco Tools AB, Sweden.
    Johansson Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Seco Tools AB, Sweden.
    Tasnadi, Ferenc
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Muecklich, F.
    Saarland University, Germany.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Exploring the high entropy alloy concept in (AlTiVNbCr)N2017In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 636, p. 346-352Article in journal (Refereed)
    Abstract [en]

    We have explored the high entropy alloy (HEA) concept in the AlTiVNbCr-nitride material system. (AlTiVNbCr)N coatings synthesized by reactive cathodic arc deposition are close to an ideal cubic solid solution with a positive mean-field enthalpy of mixing of 0.06 eV/atom. First principle calculations showa higher thermodynamic stability for the solid solution relative to their binaries thereby indicating a possible entropy stabilization at a temperature above 727 degrees C. However, the elevated temperature annealing experiments show that the solid solution decomposes to w-AlN and c-(TiVNbCr)N. The limited thermal stability of the solid solution is investigated in relation to several thermodynamic parameters. We suggest that the HEA designed multiprincipal element (AlTiVNbCr) N solid solutions are in a metastable state. (C) 2017 Published by Elsevier B.V.

  • 41.
    Yalamanchili, Kumar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Forsén, Rikard
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Jiménez-Piqué, Emilio
    Departament de Ciència del Materials i Enginyeria Metal·lúrgica, Universitat Politècnica de Catalunya, Barcelona, Spain.
    Johansson Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Roa, J.J.
    Department of Materials Science and Metallurgical Engineering, University of Barcelona, Barcelona, Spain.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Structure, deformation and fracture of arc evaporated Zr-Si-N ternary hard films2014In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 258, p. 1100-1107Article in journal (Refereed)
    Abstract [en]

    Zr-Si-N films with varying Si contents were grown on WC-Co substrates with an industrial scale reactive cathodic arc deposition technique. The microstructural changes correlate to variation in mechanical properties with different deformation mechanisms dominating for different structures. Si forms a substitutional solid solution in the cubic ZrN lattice up to 1.8 at. % in a fine columnar structure. Further Si additions results in precipitation of an amorphous (a)-SiNX phase and evolution of a nanocomposite structure (nc ZrN-a SiNX) which has completely suppressed the columnar structure at 6.3 at. % Si. The rotation-induced artificial layering during film growth was used as a marker to visualize the deformation of the film. A dislocation-based homogeneous plastic deformation mechanism dominates the columnar structure, while grain boundary sliding is the active mechanism mediating heterogeneous plastic deformation in the nanocomposite structure. Film hardness increases with increasing Si content in the columnar structure due to an effective solid solution strengthening. The deformation mechanism of localized grain boundary sliding in the nanocomposite structure results in lower hardness. When cracking is induced by indentation, the fine columnar structure exhibits pronounced crack deflection that results in higher fracture resistance compared to the nanocomposite films.

  • 42.
    Yalamanchili, Kumar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Roa, J.J.
    Department of Materials Science and Metallurgical Engineering, University of Barcelona, Barcelona, Spain.
    Jiménez-Piqué, Emilio
    Departament de Ciència del Materials i Enginyeria Metal·lúrgica, Universitat Politècnica de Catalunya, Barcelona, Spain.
    Johansson Jöesaar, Matts P.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Influence of microstructure and mechanical properties on the wear behavior of reactive arc deposited Zr-Si-N coatingsManuscript (preprint) (Other academic)
    Abstract [en]

    Zr-Si-N coatings were grown over WC-Co substrates by an industrial reactive arc deposition technique. Si content of the coatings was varied between 0.2 and 6.3 at. % to cause a microstructural transition from a columnar to an equiaxed nanocomposite microstructure resulting in alterations of the mechanical properties such as hardness, elastic modulus, and fracture resistance. A reciprocating sliding wear test with a counter material of WC-Co shows a systematic change in wear rate as a function of Si content of the coatings. A maximum wear rate of 1.4x10-5 mm3/Nm is seen for the coating with 1.8 at. % Si (columnar microstructure), which then gradually decreases to 0.6x10-5 mm3/Nm at 6.3 at. % Si (nanocomposite structure). Electron microscopy observations of the wear track reveal tribooxidation as the dominating wear mode. The growth rate of the tribo-oxide layer is the wear rate determining mechanism. Higher growth rate of tribo-oxide layer in the columnar structured coating leads to layer delamination and high wear rate. While the lower growth rate of tribo-oxide layer in the nanocomposite coating results in reduced wear rate of the coatings. Nanocomposite coatings show superior resistance to both static and tribo-oxidation compared to the columnar structured coatings.

  • 43.
    Yang, J.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Universitat Politècnica de Catalunya, Barcelona 08028, Spain.
    Roa, J. J.
    University of Politecn Cataluna, Spain; University of Politecn Cataluna, Spain.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson-Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. SECO Tools AB, Sweden.
    Esteve, J.
    University of Barcelona, Spain.
    Llanes, L.
    University of Politecn Cataluna, Spain; University of Politecn Cataluna, Spain.
    Substrate surface finish effects on scratch resistance and failure mechanisms of TiN-coated hardmetals2015In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 265, p. 174-184Article in journal (Refereed)
    Abstract [en]

    In this study, the influence of substrate surface finish on scratch resistance and associated failure mechanisms is investigated in the case of a TiN-coated hardmetal. Three different surface finish conditions are studied: as-sintered (AS), ground (G), and mirror-like polished (P). For G conditioned samples, scratch tests are conducted both parallel and perpendicular to the direction of the grinding grooves. It is found that coated AS, G and P samples exhibit similar critical load for initial substrate exposure and the same brittle adhesive failure mode. However, the damage scenarios are different, i.e. the substrate exposure is discrete and localized to the scratch tracks for G samples while a more pronounced and continuous exposure is seen for AS and P ones. Aiming to understand the role played by the grinding-induced compressive residual stresses, the study is extended to coated systems where ground substrates are thermal annealed (for relieving stresses) before being ion etched and coated. It yielded lower critical loads and changes in the mechanisms for the scratch-related failure; the latter depending on the relative orientation between scratching and grinding directions. (C) 2015 Elsevier B.V. All rights reserved.

  • 44.
    Yang, Jie
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. University of Politecn Cataluna, Spain.
    Roa, J. J.
    University of Politecn Cataluna, Spain; University of Politecn Cataluna, Spain.
    Schwin, M.
    SECO Tools AB, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Llanes, L.
    University of Politecn Cataluna, Spain; University of Politecn Cataluna, Spain.
    Grinding-induced metallurgical alterations in the binder phase of WC-Co cemented carbides2017In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 134, p. 302-310Article in journal (Refereed)
    Abstract [en]

    The metallic binder phase dictates the toughening behavior of WC-Co cemented carbides (hardmetals), even though it occupies a relative small fraction of the composite. Studies on deformation and phase transformation of the binder constituent are scarce. Grinding represents a key manufacturing step in machining of hardmetal tools, and is well-recognized to induce surface integrity alterations. In this work, metallurgical alterations of the binder phase in ground WC-Co cemented carbides have been assessed by a combination of electron back scattered diffraction and transmission electron microscopy techniques. The Co-base binder experiences a martensitic phase transformation from fcc to hcp crystal structure, predominantly in the first 5 mu m below the surface. The hcp fraction decreases gradually along a depth of 10 mu m. Surface Co displays severe plastic deformation under the highest strain, resulting in formation of nanocrystalline grains in the first micrometer below the surface. Microstructural refinement within the binder phase is observed even at greater depth. Stacking faults were detected in most of the refined grains. The metallurgical alterations of the binder phase modify the local stress distribution during grinding, which affects the discerned subsurface microcracking. The resulting residual stress profile is the sum of multiple subsurface changes, such as phase transformation, severe plastic deformation and grain refinement, where it is discerned that the depth profile of the transformed hcp-Co fraction coincides with the grinding-induced residual stress profile.

  • 45.
    Yang, Jie
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. University of Politecn Cataluna, Spain.
    Roa, J. J.
    University of Politecn Cataluna, Spain; University of Politecn Cataluna, Spain.
    Schwind, M.
    SECO Tools AB, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson-Jõesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Esteve, J.
    University of Barcelona, Spain.
    Llanes, L.
    University of Politecn Cataluna, Spain.
    Thermally induced surface integrity changes of ground WC-Co hardmetals2016In: 3RD CIRP CONFERENCE ON SURFACE INTEGRITY, Elsevier, 2016, Vol. 45, p. 91-94Conference paper (Refereed)
    Abstract [en]

    Ground hardmetals are exposed to high temperatures during both processing (e.g. coating deposition) and use (e.g. as a cutting tool). However, studies on thermally induced changes of surface integrity are limited. Here we address this by means of FIB/FESEM and EBSD investigation, with special focus on the binder phase characterization. Our findings indicate that thermal treatment causes two main surface modifications. First, an unexpected microporosity appears in the binder within the subsurface layer when ground surfaces are heated. Second, the metallic phase underneath the ground surface experiences metallurgical changes, in terms of grain and crystallographic phase structures. The mechanisms responsible for these modifications of the binder are discussed in terms of grinding-induced and thermally-reversed phase transformation as well as recrystallization phenomena. We also note that no additional heat treatment related changes such as microcracking and carbide fragmentation in the subsurface layer, are discerned. (C) 2016 The Authors. Published by Elsevier B.V.

  • 46.
    Yang, Jie
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. Univ Politecn Cataluna, Spain; AMES Sintered Met Components, Spain.
    Roa, J. J.
    Univ Politecn Cataluna, Spain; Univ Politecn Cataluna, Spain.
    Schwind, M.
    SECO Tools AB, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson-Jöesaar, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Esteve, J.
    Univ Barcelona, Spain.
    Llanes, L.
    Univ Politecn Cataluna, Spain; Univ Politecn Cataluna, Spain.
    Implementation of advanced characterisation techniques for assessment of grinding effects on the surface integrity of WC-Co cemented carbides2018In: Powder Metallurgy, ISSN 0032-5899, E-ISSN 1743-2901, Vol. 61, no 2, p. 100-105Article in journal (Refereed)
    Abstract [en]

    Grinding is a key step on the manufacturing process of WC-Co cemented carbides (hardmetals). In this work, an investigation of grinding effects on the surface integrity of hardmetals is conducted. It is done by combining diverse advanced characterisation techniques: X-ray diffraction, field emission-scanning electron microscopy, electron back scatter diffraction, focused ion beam - 3D tomography and transmission electron microscopy. The study is carried out in a fine-grained WC-Co grade. Besides ground state, polished surface finish condition is assessed for comparison purposes. It is evidenced that grinding induces significant alterations: 3D tomography illustrates microcracking exists down to 2.5 mu m depth with a highly anisotropic distribution at the subsurface, large compressive residual stresses extending until subsurface levels of about 12 mu m, and phase transformation of binder from the original fcc phase into the hcp one, as well as severe plastic deformation observed within the binder at the surface level.

  • 47.
    Yang, Jing
    et al.
    University of Politecn Cataluna, Spain.
    Garcia Marro, F.
    University of Politecn Cataluna, Spain; University of Politecn Cataluna, Spain.
    Trifonov, T.
    University of Politecn Cataluna, Spain.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson-Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Llanes, L.
    University of Politecn Cataluna, Spain; University of Politecn Cataluna, Spain.
    Contact damage resistance of TiN-coated hardmetals: Beneficial effects associated with substrate grinding2015In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 275, p. 133-141Article in journal (Refereed)
    Abstract [en]

    Contact loading is a common service condition for coated hardmetal tools and components. Substrate grinding represents a key step within the manufacturing chain of these coated systems. Within this context, the influence of surface integrity changes caused by abrasive grinding of the hardmetal substrate, prior to coating, is evaluated with respect to contact damage resistance. Three different substrate surface finish conditions are studied: ground (G), mirror-like polished (P) and ground plus heat-treated (GTT). Tests are conducted by means of spherical indentation under increasing monotonic load and the contact damage resistance is assessed. Substrate grinding enhances resistance against both crack nucleation at the coating surface and subsequent propagation into the hardmetal substrate. Hence, crack emergence and damage evolution is effectively delayed for the coated G condition, as compared to the reference P one. The observed system response is discussed on the basis of the beneficial effects associated with compressive residual stresses remnant at the subsurface level after grinding, ion-etching and coating. The influence of the stress state is further corroborated by the lower contact damage resistance exhibited by the coated GTT specimens. Finally, differences observed on the interaction between indentation-induced damage and failure mode under flexural testing points in the direction that substrate grinding also enhances damage tolerance of the coated system when exposed to contact loads.

  • 48.
    Yang, Jing
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. University of Politecn Cataluna, Spain.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Johansson-Joesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Llanes, L.
    University of Politecn Cataluna, Spain; University of Politecn Cataluna, Spain.
    Influence of substrate microstructure and surface finish on cracking and delamination response of TiN-coated cemented carbides2016In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 352-353, p. 102-111Article in journal (Refereed)
    Abstract [en]

    The cracking and delamination of TiN-coated hardmetals (WC-Co cemented carbides) when subjected to Brale indentation were studied. Experimental variables were substrate microstructure related to low (6 wt% Co) and medium (13 wt% Co) binder content, and surface finishes associated with grinding and polishing stages before film deposition. Brale indentation tests were conducted on both coated and uncoated hardmetals. Emphasis has been placed on assessing substrate microstructure and subsurface finish effects on load levels at which cracking and delamination phenomena emerge, the type of cracking pattern developed, and how fracture mechanisms evolve with increasing load. It is found that polished and coated hardmetals are more brittle (radial cracking) and the adhesion strength (coating delamination) diminishes with decreasing binder content. Such a response is discussed on the basis of the influence of intrinsic hardness/brittleness of the hardmetal substrate on both cracking at the subsurface level and effective stress state, particularly regarding changes in shear stress component. Grinding promotes delamination compared to the polished condition, but strongly inhibits radial cracking. This is a result of the interaction between elastic-plastic deformation imposed during indentation and several grinding-induced effects: remnant compressive stress field, pronounced surface texture and micro cracking within a thin altered subsurface layer. As a consequence, coating spallation prevails over radial cracking as the main mechanism for energy dissipation in ground and coated hardmetals. (C) 2016 Elsevier B.V. All rights reserved.

  • 49.
    Zhu, Jianqiang
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools, Fagersta, Sweden.
    Polcik, Peter
    PLANSEE Composite Materials GmbH.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Influence of Ti-Si cathode grain size on the cathodic arc process and resulting Ti-Si-N coatings2013In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 235, no 25, p. 637-647Article in journal (Refereed)
    Abstract [en]

    The influence of the Ti-Si cathode grain size on cathodic arc processes and resulting Ti-Si-N coating synthesis has been studied. 63 mm Ti-Si cathodes containing 20-25 at % Si with four dedicated grain size of ~8 µm, ~20 µm, ~110 µm, and ~600 µm were fabricated via spark plasma sintering or hot isostatic pressing. They were evaporated in 2 Pa nitrogen atmosphere in an industrial-scale arc deposition system and the Ti-Si-N coatings were grown at 50 A, 70 A, and 90 A arc current. The composition and microstructure of the virgin and worn cathode surfaces as well as the resulting coatings were characterized using optical and electron microscopy, x-ray diffraction, elastic recoil detection analysis, x-ray photoelectron spectroscopy, and nanoindentation. The results show that the existence of multiple phases with different work function values directly influences the cathode spot ignition behavior and also the arc movement and appearance. Specifically, there is a preferential erosion of the Ti5Si3-phase grains. By increasing the grain size of the virgin cathode, the preferential erosion is enhanced, such that the cathode surface morphology roughens substantially after 600 Ah arc discharging. The deposition rate of the Ti-Si-N coating is increased with decreasing grain size of the evaporated Ti-Si cathodes. The composition, droplet density, and droplet shape of the coatings are influenced by the arc movement, which is also shown to depend on the cathode grain size.

  • 50.
    Zhu, Jianqiang
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Syed, Muhammad Bilal
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Polcik, Peter
    PLANSEE Composite Materials GmbH, Germany.
    Håkansson, G.
    Ionbond Sweden AB, Linköping, Swedeb.
    Johansson Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools, Fagersta, Sweden.
    Ahlgren, M.
    Sandvik Coromant, Stockholm, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Effects of cathode grain size and substrate fixturing on the microstructure evolution of arc evaporated Cr-cathodes and Cr-N coating synthesis2014In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 32, no 2, p. 021515-Article in journal (Refereed)
    Abstract [en]

    The influence of the cathode grain size and the substrate fixturing on the microstructure evolution of the Cr cathodes and the resulting Cr-N coating synthesis is studied. Hot isostatic pressed Cr cathodes with three different grain sizes were arc evaporated in a nitrogen atmosphere and Cr-N coatings were deposited on cemented carbide substrate at 2 and 4 Pa nitrogen pressure, respectively. The Cr cathodes before and after arc discharging are composed of polycrystalline α-Cr regardless of the grain size. A converted layer forms on the Cr cathode surface and its microstructure differs with the cathode grain size. A stationary substrate fixturing results in ditches covering the cathode surface while a single rotating fixturing does not. The increased grain size of the virgin Cr cathodes enhances the quantities of the ditches. The possible causes are addressed. At 2 Pa nitrogen pressure, the Cr-N coatings deposited with the single rotating fixturing comprise only cubic CrN phase while the ones deposited with the stationary fixturing contain a mixture of hexagonal Cr2N and cubic CrN phases. By the increasing grain size of the Cr cathode, the droplet density of the Cr-N coatings increase somewhat while the hardness decreases for the Cr-N coatings deposited with stationary fixturing at 2 Pa nitrogen pressure.

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