liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Supertoughening in B1 transition metal nitride alloys by increased valence electron concentration
Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.ORCID iD: 0000-0002-2837-3656
Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
2011 (English)In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 59, no 5, 212-2134 p.Article in journal (Refereed) Published
Abstract [en]

We use density functional theory calculations to explore the effects of alloying cubic TiN and VN with transition metals M = Nb, Ta, Mo, W in 50% concentrations. The obtained ternaries are predicted to become supertough as they are shown to be harder and significantly more ductile compared to the reference binaries. The primary electronic mechanism of this supertoughening effect is shown in a comprehensive electronic structure analysis of these compounds to be the increased valence electron concentration intrinsic to these ternaries. Our investigations reveal the complex nature of chemical bonding in these compounds, which ultimately explains the observed selective response to stress. The findings presented in this paper thus offer a design route for the synthesis of supertough transition metal nitride alloys via valence electron concentration tuning.

Place, publisher, year, edition, pages
Elsevier , 2011. Vol. 59, no 5, 212-2134 p.
Keyword [en]
Cubic, transition metal nitrides, mechanical properties, ab initio, dft, ductility, toughness, electronic structure
National Category
Condensed Matter Physics
Identifiers
URN: urn:nbn:se:liu:diva-63361DOI: 10.1016/j.actamat.2010.12.013ISI: 000287775400026OAI: oai:DiVA.org:liu-63361DiVA: diva2:378895
Funder
Swedish Research Council
Note
On the defence day the status of the article was: Accepted. Original Publication: Davide Giuseppe Sangiovanni, Lars Hultman and Valeriu Chirita, Supertoughening in B1 transition metal nitride alloys by increased valence electron concentration, 2011, Acta Materialia, (59), 5, 212-2134. http://dx.doi.org/10.1016/j.actamat.2010.12.013 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/ Available from: 2010-12-16 Created: 2010-12-16 Last updated: 2017-12-11Bibliographically approved
In thesis
1. Toughness enhancement in transition metal nitrides
Open this publication in new window or tab >>Toughness enhancement in transition metal nitrides
2011 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Toughness enhancements can be induced in cubic-B1 transition metal nitride alloys by an increased occupation of the d-t2g metallic states. In this Licentiate Thesis I use density functional theory to investigate the mechanical properties of TiN and VN and of the ternaries obtained by replacing 50% of Ti and V atoms with M (M = V, Nb, Ta, Mo, and W) to form ordered structures with minimum number of inter-metallic bonds. The calculated values of elastic constants and moduli show that ternary alloys with high valence electron concentrations (M = Mo and W), have large reductions in shear moduli and C44 elastic constants, while retaining the typically high stiffness and incompressibility of ceramic materials. These results point to significantly improved ductility in the ternary compounds. This important combination of strength and ductility, which equates to material toughness, stems from alloying with valence electron richer dmetals. The increased valence electron concentration strengthens metal–metal bonds by filling metallic d-t2g states, and leads to the formation of a layered electronic configuration upon shearing. Comprehensive electronic structure calculations demonstrate that in these crystals, stronger Ti/V – N and weaker M – N bonds are formed as the valence electron concentration is increased. This phenomenon ultimately enhances ductility by promoting dislocation glide through the activation of an easy slip system.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2011. 26 p.
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1462
Keyword
cubic, transition metal nitrides, mechanical properties, ab initio, dft, toughness, ductility, electronic structure
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-63364 (URN)LIU-TEK-LIC-2011:2 (Local ID)978-91-7393-257-8 (ISBN)LIU-TEK-LIC-2011:2 (Archive number)LIU-TEK-LIC-2011:2 (OAI)
Presentation
2011-02-03, Planck, Physics building, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2010-12-30 Created: 2010-12-16 Last updated: 2016-08-31Bibliographically approved
2. Transition Metal Nitrides: Alloy Design and Surface Transport Properties using Ab-initio and Classical Computational Methods
Open this publication in new window or tab >>Transition Metal Nitrides: Alloy Design and Surface Transport Properties using Ab-initio and Classical Computational Methods
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Enhanced toughness in brittle ceramic materials, such as transition metal nitrides (TMN), is achieved by optimizing the occupancy of shear-sensitive metallic electronic-states. This is the major result of my theoretical research, aimed to solve an inherent long-standing problem for hard ceramic protective coatings: brittleness. High hardness, in combination with high toughness, is thus one of the most desired mechanical/physical properties in modern coatings. A significant part of this PhD Thesis is dedicated to the density functional theory (DFT) calculations carried out to understand the electronic origins of ductility, and to predict novel TMN alloys with optimal hardness/toughness ratios. Importantly, one of the TMN alloys identified in my theoretical work has subsequently been synthesized in the laboratory and exhibits the predicted properties.

The second part of this Thesis concerns molecular dynamics (MD) simulations of Ti, N, and TiNx adspecies diffusion on TiN surfaces, chosen as a model material, to provide unprecedented detail of critical atomic-scale transport processes, which dictate the growth modes of TMN thin films. Even the most advanced experimental techniques cannot provide sufficient information on the kinetics and dynamics of picosecond atomistic processes, which affect thin films nucleation and growth. Information on these phenomena would allow experimentalists to better understand the role of deposition conditions and fine tune thin films growth modes, to tailor coatings properties to the requirements of different applications. The MD simulations discussed in the second part of this PhD Thesis, predict that Ti adatoms and TiN2 admolecules are the most mobile species on TiN(001) terraces. Moreover, these adspecies are rapidly incorporated at island descending steps, and primarily contribute to layer-by-layer growth. In contrast, TiN3 tetramers are found to be essentially stationary on both TiN(001) terraces and islands, and thus constitute the critical nuclei for three-dimensional growth.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2013. 75 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1513
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-91379 (URN)978-91-7519-638-1 (ISBN)
Public defence
2013-05-23, Planck, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2013-04-23 Created: 2013-04-23 Last updated: 2016-08-31Bibliographically approved

Open Access in DiVA

fulltext(1471 kB)965 downloads
File information
File name FULLTEXT01.pdfFile size 1471 kBChecksum SHA-512
d7e0147e6eb2142b9cac9193045c16f2eb3a3fc0eced00bb9c04f41f3b26b019f3d5a93fbcfcd29a6783908cca91d481faa2e6b58dcd2b5b9dc4792689213cb8
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Authority records BETA

Sangiovanni, Davide GiuseppeHultman, LarsChirita, Valeriu

Search in DiVA

By author/editor
Sangiovanni, Davide GiuseppeHultman, LarsChirita, Valeriu
By organisation
Thin Film PhysicsThe Institute of Technology
In the same journal
Acta Materialia
Condensed Matter Physics

Search outside of DiVA

GoogleGoogle Scholar
Total: 965 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 327 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf