Effect of solid-solution strengthening on deformation mechanisms and strain hardening in medium-entropy V1-xCrxCoNi alloys

Hyun Chung ¹Dae Woong Kim ²Woo Jin Cho ³Heung Nam Han ³Yuji Ikeda ⁴Shoji Ishibashi ⁵Fritz K?rmann ⁶Seok Su Sohn¹

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作者信息

1. Department of Materials Science and Engineering,Korea University,Seoul 02841,South Korea
2. Center for High Entropy Alloys,Pohang University of Science and Technology,Pohang 37673,South Korea
3. Department of Materials Science and Engineering and Research Institute of Advanced Materials,Seoul National University,Seoul 08826,South Korea
4. Institute for Materials Science,University of Stuttgart,Pfaffenwaldring 55,Stuttgart 70569,Germany;Computational Materials Design,Max-Planck-Institut für Eisenforschung GmbH,Max-Planck-Strabe 1,Düisseldorf 40237,Germany
5. Computational Materials Design,Max-Planck-Institut für Eisenforschung GmbH,Max-Planck-Strabe 1,Düisseldorf 40237,Germany;Research Center for Computational Design of Advanced Functional Materials(CD-Fmat),National Institute of Advanced Industrial Science and Technology(AIST),Tsukuba,Ibaraki 305-8568,Japan
6. Computational Materials Design,Max-Planck-Institut für Eisenforschung GmbH,Max-Planck-Strabe 1,Düisseldorf 40237,Germany;Department of Materials Science and Engineering,Delft University of Technology,Mekelweg,2,Delft 2628 CD,the Netherlands
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Abstract

High-and medium-entropy alloys(HEAs and MEAs)possess high solid-solution strength.Numerous in-vestigations have been conducted on its impact on yield strength,however,there are limited reports regarding the relation between solid-solution strengthening and strain-hardening rate.In addition,no attempt has been made to account for the dislocation-mediated plasticity;most works focused on twinning-or transformation-induced plasticity(TWIP or TRIP).In this work we reveal the role of solid-solution strengthening on the strain-hardening rate via systematically investigating evolutions of defor-mation structures by controlling the Cr/V ratio in prototypical V1-xCrxCoNi alloys.Comparing the TWIP of CrCoNi with the dislocation slip of V0.4Cr0.6CoNi,the hardening rate of CrCoNi was superior to slip-band refinements of V0.4Cr0.6CoNi due to the dynamic Hall-Petch effect.However,as V content increased fur-ther to V0.7Cr0.3CoNi and VCoNi,their rate of slip-band refinement in V0.7Cr0.3CoNi and VCoNi with high solid-solution strength surpassed that of CrCoNi.Although it is generally accepted in conventional alloys that deformation twinning results in a higher strain-hardening rate than dislocation-mediated plasticity,we observed that the latter can be predominant in the former under an activated huge solid-solution strengthening effect.The high solid-solution strength lowered the cross-slip activation and consequently retarded the dislocation rearrangement rate,i.e.,the dynamic recovery.This delay in the hardening rate decrease,therefore,increased the strain-hardening rate,results in an overall higher strain-hardening rate of V-rich alloys.

Key words

Medium-entropy alloy/Tensile property/Solid-solution strength/Strain-hardening rate/Stacking fault energy

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基金项目

This work was financially supported by the POSCO Science Fel-lowship of POSCO TJ Park Foundation,the National Research Foun-dati(NRF-2020R1C1C1003554)

Creative Ma-terials Discovery Program of the National Research Foundation of Korea(NRF)funded by the Ministry of Science and(NRF-2016M3D1A1023384)

and the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)

and the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(P0002019)

出版年

2022

材料科学技术(英文版)

中国金属学会中国材料研究学会中国科学院金属研究所

材料科学技术(英文版)

CSTPCDCSCDSCI

影响因子：0.657

ISSN：1005-0302

参考文献量72

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