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Title: Phase stability, physical properties and strengthening mechanisms of concentrated solid solution alloys

Abstract

Here, we review recent research developments in a special class of multicomponent concentrated solid solution alloys (CSAs) – of which the recently discovered high entropy alloys (HEAs) are exemplars – that offer a new paradigm for the development of next generation structural materials. This review focuses on the role of inherent extreme chemical complexity on the phase stability, electronic, transport, and mechanical properties of this remarkable class of disordered solid solution alloys. Both experimental observations and theoretical models indicate that the phase stability of HEAs goes beyond the original conjecture that these alloys are stabilized by configurational/mixing entropy; rather, it results from competition between the homogeneously disordered phase and phase separation/intermetallic compound formation. Although the number of single-phase HEAs with equiatomic composition is limited, those that do exist often exhibit remarkable electronic, magnetic, transport, and mechanical properties. For the mechanical response, we discuss the solution strengthening mechanism which governs the strength and deformation behaviors of the CSAs, as well as the increasing evidence that low stacking fault energies (deformation twinning) plays an important role in the low temperature strength and ductility of CrMnFeCoNi related alloys. We also review the current understanding of the role of the number and type ofmore » alloy elements in determining the electronic, magnetic, and transport properties, in particular the dominant role of magnetic interactions in the properties of 3d-transition metal based alloys. Finally, we emphasize that, despite rapid progress in characterization and understanding of the phase stability and physical/mechanical responses of CSAs, there remain significant challenges to fully exploring the new paradigm that these alloys represent.« less

Authors:
ORCiD logo [1];  [1];  [2]; ORCiD logo [2]; ORCiD logo [1]; ORCiD logo [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Energy Frontier Research Centers (EFRC) (United States). Energy Dissipation to Defect Evolution (EDDE)
Sponsoring Org.:
USDOE
OSTI Identifier:
1474729
Alternate Identifier(s):
OSTI ID: 1495886
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Current Opinion in Solid State and Materials Science
Additional Journal Information:
Journal Volume: 21; Journal Issue: 5; Journal ID: ISSN 1359-0286
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Concentrated solid solutions; High entropy alloys; Phase stability; Physical/mechanical properties; Strengthening mechanisms

Citation Formats

Wu, Zhenggang, Troparevsky, M. Claudia, Gao, Y. F., Morris, James R., Stocks, George Malcolm, and Bei, Hongbin. Phase stability, physical properties and strengthening mechanisms of concentrated solid solution alloys. United States: N. p., 2017. Web. doi:10.1016/j.cossms.2017.07.001.
Wu, Zhenggang, Troparevsky, M. Claudia, Gao, Y. F., Morris, James R., Stocks, George Malcolm, & Bei, Hongbin. Phase stability, physical properties and strengthening mechanisms of concentrated solid solution alloys. United States. doi:10.1016/j.cossms.2017.07.001.
Wu, Zhenggang, Troparevsky, M. Claudia, Gao, Y. F., Morris, James R., Stocks, George Malcolm, and Bei, Hongbin. Mon . "Phase stability, physical properties and strengthening mechanisms of concentrated solid solution alloys". United States. doi:10.1016/j.cossms.2017.07.001. https://www.osti.gov/servlets/purl/1474729.
@article{osti_1474729,
title = {Phase stability, physical properties and strengthening mechanisms of concentrated solid solution alloys},
author = {Wu, Zhenggang and Troparevsky, M. Claudia and Gao, Y. F. and Morris, James R. and Stocks, George Malcolm and Bei, Hongbin},
abstractNote = {Here, we review recent research developments in a special class of multicomponent concentrated solid solution alloys (CSAs) – of which the recently discovered high entropy alloys (HEAs) are exemplars – that offer a new paradigm for the development of next generation structural materials. This review focuses on the role of inherent extreme chemical complexity on the phase stability, electronic, transport, and mechanical properties of this remarkable class of disordered solid solution alloys. Both experimental observations and theoretical models indicate that the phase stability of HEAs goes beyond the original conjecture that these alloys are stabilized by configurational/mixing entropy; rather, it results from competition between the homogeneously disordered phase and phase separation/intermetallic compound formation. Although the number of single-phase HEAs with equiatomic composition is limited, those that do exist often exhibit remarkable electronic, magnetic, transport, and mechanical properties. For the mechanical response, we discuss the solution strengthening mechanism which governs the strength and deformation behaviors of the CSAs, as well as the increasing evidence that low stacking fault energies (deformation twinning) plays an important role in the low temperature strength and ductility of CrMnFeCoNi related alloys. We also review the current understanding of the role of the number and type of alloy elements in determining the electronic, magnetic, and transport properties, in particular the dominant role of magnetic interactions in the properties of 3d-transition metal based alloys. Finally, we emphasize that, despite rapid progress in characterization and understanding of the phase stability and physical/mechanical responses of CSAs, there remain significant challenges to fully exploring the new paradigm that these alloys represent.},
doi = {10.1016/j.cossms.2017.07.001},
journal = {Current Opinion in Solid State and Materials Science},
issn = {1359-0286},
number = 5,
volume = 21,
place = {United States},
year = {2017},
month = {8}
}

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