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Moverare, Johan, ProfessorORCID iD iconorcid.org/0000-0002-8304-0221
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Publications (10 of 144) Show all publications
Nordström, J., Dong, Z., Lautrup, L., Siriki, R., Vitos, L., Moverare, J., . . . Chai, G. (2024). Temperature study of deformation twinning behaviour in Nickel-base Superalloy 625. Materials Science & Engineering: A, Article ID 146628.
Open this publication in new window or tab >>Temperature study of deformation twinning behaviour in Nickel-base Superalloy 625
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2024 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, article id 146628Article in journal (Refereed) Epub ahead of print
Abstract [en]

Deformation behaviour in the Nickel-base superalloy 625 has been studied by tensile testing at four temperatures: 295, 223, 173 and 77 K. The microstructure has been investigated using TEM, FIB-SEM, EBSD and ECCI techniques. Deformation in the alloy turns out to be a competitive course of events between at least two deformation mechanisms, namely dislocation slip and deformation twinning. Slip is the predominant deformation mechanism at higher temperatures. While at 77 K, deformation induced twinning gives an extra degree of freedom as one of the main deformation mechanisms, i.e., the material shows a twin induced plasticity, TWIP, behaviour. Ab initio calculations indicate that the influence of cryogenic/sub-zero temperatures on the stacking fault energy of this alloy can be limited and that the formation of deformation twins cannot be determined solely by the stacking fault energy. The results implies that it is the critical strain and strain hardening rate that influences the deformation twinning onset and twinning rate.

Keywords
Ni-base alloy, Superalloy, Deformation induced twinning, Density function theory, Stacking fault energy
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:liu:diva-203601 (URN)10.1016/j.msea.2024.146628 (DOI)
Available from: 2024-05-20 Created: 2024-05-20 Last updated: 2024-05-20Bibliographically approved
Pauzon, C., Raza, A., Hanif, I., Dubiez-Le Goff, S., Moverare, J. & Hryha, E. (2023). Effect of layer thickness on spatter properties during laser powder bed fusion of Ti-6Al-4V. Powder Metallurgy, 66(4), 333-342
Open this publication in new window or tab >>Effect of layer thickness on spatter properties during laser powder bed fusion of Ti-6Al-4V
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2023 (English)In: Powder Metallurgy, ISSN 0032-5899, E-ISSN 1743-2901, Vol. 66, no 4, p. 333-342Article in journal (Refereed) Published
Abstract [en]

High layer thicknesses for laser powder bed fusion are promising for productivity increase. However, these are associated with increased process instability, spatter generation and powder degradation, crucial for alloys sensitive to oxygen. The effect of increasing layer thickness from 30 to 60 mu m is studied focusing on Ti-6Al-4V spatter formation during LPBF and its characterisation, with scanning and transmission electron microscopy, combustion analysis and X-ray photoelectron spectroscopy. Results indicate that spatters are covered with a uniform Ti-Al-based oxide layer and Al-rich oxide particulates, the thickness of which is about twice that present on virgin powder. The oxygen content was about 60% higher in spatters compared to the virgin powder. The study highlights that increasing the layer thickness to 60 mu m permits to reduce the total generation of spatters by similar to 40%, while maintaining similar spatter characteristics and static tensile properties. Hence, this allows to increase build rate without compromising process robustness.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2023
Keywords
Additive manufacturing; Laser powder bed fusion; Ti-6Al-4V spatter; Spatter generation; Powder degradation; Layer thickness; X-ray photoelectron spectroscopy; Transmission electron microscopy
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:liu:diva-193002 (URN)10.1080/00325899.2023.2192036 (DOI)000952742700001 ()
Available from: 2023-04-13 Created: 2023-04-13 Last updated: 2024-03-21Bibliographically approved
Cui, L., Yu, C.-H., Jiang, S., Sun, X., Peng, R. L., Lundgren, J.-E. & Moverare, J. (2022). A new approach for determining GND and SSD densities based on indentation size effect: An application to additive-manufactured Hastelloy X. Journal of Materials Science & Technology, 96, 295-307
Open this publication in new window or tab >>A new approach for determining GND and SSD densities based on indentation size effect: An application to additive-manufactured Hastelloy X
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2022 (English)In: Journal of Materials Science & Technology, ISSN 1005-0302, Vol. 96, p. 295-307Article in journal (Refereed) Published
Abstract [en]

Dislocation plays a crucial role in controlling the strength and plasticity of bulk materials. However, determining the densities of geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) is one of the classical problems in material research for several decades. Here, we proposed a new approach based on indentation size effect (ISE) and strengthening theories. This approach was performed on a laser powder bed fused (L-PBF) Hastelloy X (HX), and the results were verified by the Hough-based EBSD and modified Williamson–Hall (m-WH) methods. Furthermore, to better understand the new approach and essential mechanisms, an in-depth investigation of the microstructure was conducted. The distribution of dislocations shows a clear grain orientation-dependent: low density in large <101> preferentially orientated grains while high density in fine <001> orientated grains. The increment of strengthening in L-PBF HX is attributed to a huge amount of edge-GNDs. Planar slip is the main operative deformation mechanism during indentation tests, and the slip step patterns depend mostly on grain orientations and stacking fault energy. This study provides quantitative results of GND and SSD density for L-PBF HX, which constructs a firm basis for future quantitative work on other metals with different crystal structures.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Microstructure characterization, Indentation size effect, Hastelloy X, Geometrically necessary dislocation, Statistically stored dislocation
National Category
Applied Mechanics
Identifiers
urn:nbn:se:liu:diva-177714 (URN)10.1016/j.jmst.2021.05.005 (DOI)
Note

Funding agencies: The Swedish Governmental Agency for Innovation Systems (Vinnova Grant No. 2016-05175) and the Center for Additive Manufacturing-metal (CAM2). Siemens Energy is acknowledged for providing the samples.

Available from: 2021-07-01 Created: 2021-07-01 Last updated: 2023-12-28
Yu, C.-H., Peng, R. L., Lee, T. L., Luzin, V., Lundgren, J.-E. & Moverare, J. (2022). Anisotropic behaviours of LPBF Hastelloy X under slow strain rate tensile testing at elevated temperature. Materials Science & Engineering: A, 844, Article ID 143174.
Open this publication in new window or tab >>Anisotropic behaviours of LPBF Hastelloy X under slow strain rate tensile testing at elevated temperature
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2022 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 844, article id 143174Article in journal (Refereed) Published
Abstract [en]

To improve the understanding of high temperature mechanical behaviours of LPBF Ni-based superalloys, this work investigates the influence of an elongated grain structure and characteristic crystallographic texture on the anisotropic tensile behaviours in LPBF Hastelloy X (HX) at 700 °C. Two types of loading conditions have been examined to analyse the anisotropy related to the building direction (BD), including the vertical loading (loading direction//BD) and the horizontal loading (loading direction ⊥ BD). To probe the short-term creep behaviours, slow strain rate tensile testing (SSRT) has been applied to address the strain rate dependent inelastic strain accumulation. In-situ time-of-flight neutron diffraction upon loading was performed to track the anisotropic lattice strain evolution in the elastic region and the texture evolution in the plastic region. Combined with the post microstructure and fracture analysis, the anisotropic mechanical behaviours are well correlated with the different microstructural responses between vertical and horizontal loading and the different strain rates. A better creep performance is expected in the vertical direction with the consideration of the better ductility and the higher level of texture evolution.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2022
Keywords
Creep, Slow strain rate tensile testing (SSRT), Time-of-flight neutron diffraction, Texture, Ductility, Elastic constants
National Category
Applied Mechanics
Identifiers
urn:nbn:se:liu:diva-184826 (URN)10.1016/j.msea.2022.143174 (DOI)000797873300002 ()
Note

Funding agencies: Swedish Governmental Agency for Innovation Systems (Vinnova) [2016-05175]; AFM at Linkoping University; Centre for Additive Manufacturing-metal (CAM2); Science and Technology Facilities Council [2016-05175];  [2009-00971];  [RB2010043]

Available from: 2022-05-09 Created: 2022-05-09 Last updated: 2022-06-08
Kahlin, M., Ansell, H. & Moverare, J. (2022). Fatigue crack growth for through and part-through cracks in additively manufactured Ti6Al4V. International Journal of Fatigue, 155, Article ID 106608.
Open this publication in new window or tab >>Fatigue crack growth for through and part-through cracks in additively manufactured Ti6Al4V
2022 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 155, article id 106608Article in journal (Refereed) Published
Abstract [en]

Critical aerospace parts require damage tolerance analysis to determine the inspection intervals in-service. Such analyses, based on linear fracture mechanics, require that the fatigue crack growth (FCG) rate relation to the stress intensity factor range is applicable independent of geometry and stress. FCG rates for laser powder bed fusion Ti6Al4V material for conventional compact tension (CT) specimens have therefore been compared to FCG rates for specimens with a crack configuration more technically relevant from an industrial and engineering perspective. The FCG rates corresponded very well and data obtained with CT-specimens can therefore be considered relevant for general damage tolerance predictions.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Additive manufacturing, Ti6Al4V, Fatigue crack growth, Damage tolerance, Aerospace
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:liu:diva-180642 (URN)10.1016/j.ijfatigue.2021.106608 (DOI)000789644700004 ()2-s2.0-85117781757 (Scopus ID)
Note

Funding agencies: Swedish Foundation for Strategic Research [14-0060]; Clean Sky 2 joint undertaking under the European Unions Horizon 2020 research and innovation programme; Saab AB

Available from: 2021-10-26 Created: 2021-10-26 Last updated: 2022-05-18Bibliographically approved
Wärner, H., Chai, G., Moverare, J. & Calmunger, M. (2022). High Temperature Fatigue of Aged Heavy Section Austenitic Stainless Steels. Materials, 15(1), Article ID 84.
Open this publication in new window or tab >>High Temperature Fatigue of Aged Heavy Section Austenitic Stainless Steels
2022 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 15, no 1, article id 84Article in journal (Refereed) Published
Abstract [en]

This work investigates two austenitic stainless steels, Sanicro 25 which is a candidate for high temperature heavy section components of future power plants and Esshete 1250 which is used as a reference material. The alloys were subjected to out-of-phase (OP) thermomechanical fatigue (TMF) testing under strain-control in the temperature range of 100 ∘C to 650 ∘C. Both unaged and aged (650 ∘C, 3000 h) TMF specimens were tested to simulate service degradation resulting from long-term usage. The scanning electron microscopy methods electron backscatter diffraction (EBSD) and energy dispersive spectroscopy (EDS) were used to analyse and discuss active failure and deformation mechanisms. The Sanicro 25 results show that the aged specimens suffered increased plastic straining and shorter TMF-life compared to the unaged specimens. The difference in TMF-life of the two test conditions was attributed to an accelerated microstructural evolution that provided decreased the effectiveness for impeding dislocation motion. Ageing did not affect the OP-TMF life of the reference material, Esshete 1250. However, the structural stability and its resistance for cyclic deformation was greatly reduced due to coarsening and cracking of the strengthening niobium carbide precipitates. Sanicro 25 showed the higher structural stability during OP-TMF testing compare with the reference material.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI, 2022
Keywords
high temperature austenitic stainless steels, out-of-phase thermomechanical fatigue, crack propagation analysis, electron backscatter diffraction (EBSD), energy-dispersive X-ray spectroscopy (EDS)
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-182258 (URN)10.3390/ma15010084 (DOI)000751248900001 ()35009228 (PubMedID)2-s2.0-85121749412 (Scopus ID)
Note

Funding: AB Sandvik Materials Technology in Sweden; Swedish Energy Agency through the Research Consortium of Materials Technology for Thermal Energy Processes [KME-801]

Available from: 2022-01-11 Created: 2022-01-11 Last updated: 2022-02-18Bibliographically approved
Kjellsson, H., Balachandramurthi, A. R., Moverare, J. & Hansson, T. (2022). High Temperature Fatigue Performance of Electron Beam Powder Bed Fusion Manufactured Alloy 718. Metallurgical and Materials Transactions. A, 53, 2496-2514
Open this publication in new window or tab >>High Temperature Fatigue Performance of Electron Beam Powder Bed Fusion Manufactured Alloy 718
2022 (English)In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 53, p. 2496-2514Article in journal (Refereed) Published
Abstract [en]

The microstructure and mechanical properties of additively manufactured (AM) parts have been shown to be different from that of cast and wrought counterparts. In this study, electron beam powder bed fusion (EB-PBF) fabricated Alloy 718 was exposed to three different heat treatment routes followed by strain-controlled fatigue testing at 550 degrees C. The fatigue tests were performed with specimens built with their center axis parallel and transverse relative to the build direction. The microstructure showed saturated precipitation of delta-Ni3Nb after repeated solution treatment at 954 degrees C. In contrast, no delta-Ni3Nb precipitates could be observed after a single-step solution treatment at 1025 degrees C. However, the disparity of secondary phases showed no noticeable influence on the fatigue life. A significant difference in fatigue behavior was noted between the parallel and transverse directions. The specimens loaded parallel to the elongated grains showed on average similar to 5x greater life in comparison to the perpendicularly loaded specimens. Compared to corresponding heat-treated material conditions tested at ambient temperature, the specimens showed lower life at high strain amplitude and superior life at low strain amplitude. Moreover, competitive internal and surface failure modes were observed at the lower strain amplitudes while for the higher strain ranges, surface failure modes dominated.

Place, publisher, year, edition, pages
Springer, 2022
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:liu:diva-185017 (URN)10.1007/s11661-022-06681-7 (DOI)000788952400001 ()
Note

Funding Agencies|University West

Available from: 2022-05-18 Created: 2022-05-18 Last updated: 2023-03-28Bibliographically approved
Ge, Z., Xie, G., Segersäll, M., Norman, V., Chen, Z., Moverare, J., . . . Zhang, J. (2022). Influence of Ru on the thermomechanical fatigue deformation behavior of a single crystal superalloy. International Journal of Fatigue, 156, Article ID 106634.
Open this publication in new window or tab >>Influence of Ru on the thermomechanical fatigue deformation behavior of a single crystal superalloy
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2022 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 156, article id 106634Article in journal (Refereed) Published
Abstract [en]

The deformation mechanisms of a single crystal nickel-base superalloy with and without Ru-doped have been investigated under out-of-phase thermomechanical fatigue. The Ru-doped alloy exhibits a thermomechanical fatigue life more than twice as high compared to the Ru-free alloy and a difference in thermomechanical fatigue behavior is also displayed. Microstructure studies by scanning electron microscopy and transmission electron microscopy revealed that the deformation mechanism of the Ru-free alloy in the initial stage is the movement of dislocations in the γ matrix. In the later stage of the thermomechanical fatigue test, large amounts of twins are formed in the material, and a large number of stacking faults and dislocations are sheared into the γ' precipitates. By comparing with the Ru-free alloy, the Ru-doped alloy has a higher matrix strength due to the solid solution strengthening effect of Ru, and is also prone to different deformation mechanisms. For example, the stacking faults are formed in the initial thermomechanical fatigue cycles and remain in the matrix throughout the entire thermomechanical fatigue process. The formation of twins, on the other hand, is suppressed by Ru addition. Such effects are believed to extend the thermomechanical fatigue life effectively.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Nickel-base superalloy, Single crystal, Thermomechanical fatigue, Ru, Twinning
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-181630 (URN)10.1016/j.ijfatigue.2021.106634 (DOI)000789656100001 ()2-s2.0-85118789220 (Scopus ID)
Funder
The Swedish Foundation for International Cooperation in Research and Higher Education (STINT)
Note

Funding: National Natural Science Foundation of China [51771204, U1732131, 51911530154, 51631008, 91860201]; National Science and Technology Major Project [J2019-VI-0010]; Swedish foundation for international cooperation in research and higher education (STINT) [CH2018-7851]

Available from: 2021-12-06 Created: 2021-12-06 Last updated: 2022-05-19Bibliographically approved
Palmert, F., Gustafsson, D., Almroth, P., Petersson, H., Segersäll, M. & Moverare, J. (2022). Modelling of the transition from mode I to crystallographic crack growth in a single crystal gas turbine blade alloy under service-like loading conditions. International Journal of Fatigue, 163, Article ID 107077.
Open this publication in new window or tab >>Modelling of the transition from mode I to crystallographic crack growth in a single crystal gas turbine blade alloy under service-like loading conditions
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2022 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 163, article id 107077Article in journal (Refereed) Published
Abstract [en]

In fatigue life prediction of single crystal gas turbine blades, the risk of rapid crystallographic crack growth along the close-packed planes poses a large uncertainty. A criterion is proposed to predict the transition from mode I to crystallographic crack growth, which is necessary for reliable prediction of the number of cycles from crack initiation to the onset of crystallographic crack growth. The proposed criterion is calibrated against tests performed under a wide range of conditions representative for a gas turbine blade, including isothermal fatigue crack growth tests and thermomechanical fatigue crack growth tests, some including hold times and pre-test aging.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Single crystal superalloy, TMF, Crack growth, Crystallographic crack growth, Aging, Hold time
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:liu:diva-186053 (URN)10.1016/j.ijfatigue.2022.107077 (DOI)000818487800002 ()
Note

Funding agencies: The work has been supported financially by Siemens Energy AB in Finspång, Sweden and the Swedish Energy Agency, via the Research Consortium of Materials Technology for Thermal Energy Processes, Grant No. KME-702.

Available from: 2022-06-17 Created: 2022-06-17 Last updated: 2023-12-28Bibliographically approved
Jiang, S., Peng, R., Mathis, K., Yan, H.-L., Farkas, G., Hegedues, Z., . . . Wang, Y.-D. (2022). Shear banding-induced 〈c + a〉 slip enables unprecedented strength-ductility combination of laminated metallic composites. Journal of Materials Science & Technology, 110, 260-268
Open this publication in new window or tab >>Shear banding-induced 〈c + a〉 slip enables unprecedented strength-ductility combination of laminated metallic composites
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2022 (English)In: Journal of Materials Science & Technology, ISSN 1005-0302, Vol. 110, p. 260-268Article in journal (Refereed) Published
Abstract [en]

Shear bands in metallic materials have been reported to be catastrophic because they normally lead to non-uniform plastic deformation. Ductility of laminated metallic composites deteriorates with increasing processing strain, particularly for those having hexagonal-close-packed (hcp) constituents due to inadequate slip systems and consequently prominent shear banding. Here, we propose a design strategy that counterintuitively tolerates the bands with localized strains, i.e. the shear banded laminar (SBL) structure, which promotes 〈c + a〉 dislocation activation in hcp metals and renders unprecedented strengthductility combination in hcp-metal-based composites fabricated by accumulative roll bonding (ARB). The SBL structure is characterized with one soft hcp metal constrained by adjacent hard metal in which dislocations have been accumulated near the bimetal interfaces. High-energy X-ray diffraction astonishingly reveals that more than 90% of dislocations are non-basal in Ti layers of the SBL Ti/Nb composite processed by eight ARB cycles. Moreover, 〈c + a〉 dislocations occupy a high fraction of ∼30%, promoting further 〈c + a〉 cross slip. The unique stress field tailored by both shear banding and heterophase interface-mediated deformation accommodation triggers important 〈c + a〉 slip. This SBL design is of significance for developing hcp-based laminates and other heterostructured materials with high performances.

Place, publisher, year, edition, pages
Shenyang, China: Elsevier, 2022
Keywords
Shear band; Laminated metallic composites; Ductility; High-energy X-ray diffraction; Dislocation slip
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:liu:diva-184993 (URN)10.1016/j.jmst.2021.09.032 (DOI)000788137200002 ()2-s2.0-85120416204 (Scopus ID)
Note

Funding Agencies: National Natural Science Foundation of China [51922026]; Fundamental Research Funds for the Central Universities [N20 020 05, N2007011]; 111 Project [B20029]; Czech Ministry of Education, Youth and Sports (infrastructure ESS Scandinavia-CZ) project [LM2018111]; China Scholarship Council

Available from: 2022-05-16 Created: 2022-05-16 Last updated: 2022-06-03Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-8304-0221

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