Effect of solid-solution strengthening on deformation mechanisms and strain hardening in medium-entropy V_(1-x)Cr_(x)CoNi alloys  

作　　者：Hyun Chung Dae Woong Kim Woo Jin Cho Heung Nam Han Yuji Ikeda Shoji Ishibashi Fritz Körmann Seok Su Sohn 

机构地区：[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 [5]Computational Materials Design,Max-Planck-Institut für Eisenforschung GmbH,Max-Planck-Strabe 1,Düsseldorf 40237,Germany [6]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 [7]Department of Materials Science and Engineering,Delft University of Technology,Mekelweg,2,Delft 2628 CD,the Netherlands

出　　处：《Journal of Materials Science & Technology》2022年第13期270-280,共11页材料科学技术（英文版）

基　　金：financially supported by the POSCO Science Fellowship of POSCO TJ Park Foundation,the National Research Foundation of Korea(No.NRF-2020R1C1C1003554);the Creative Materials Discovery Program of the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(No.NRF2016M3D1A1023384);the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE,P0002019,The Competency Development Program for Industry Specialist);support from the German Research Foundation(Deutsche Forschungsgemeinschaft,DFG)under the priority program 2006"CCA-HEA"。

摘　　要：High-and medium-entropy alloys(HEAs and MEAs)possess high solid-solution strength.Numerous investigations 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 solidsolution strengthening on the strain-hardening rate via systematically investigating evolutions of deformation structures by controlling the Cr/V ratio in prototypical V_(1-x)Cr_(x)CoNi alloys.Comparing the TWIP of CrCoNi with the dislocation slip of V_(0.4)Cr_(0.6)CoNi,the hardening rate of CrCoNi was superior to slip-band refinements of V_(0.4)Cr_(0.6)CoNi due to the dynamic Hall-Petch effect.However,as V content increased further to V_(0.7)Cr_(0.3)CoNi and VCoNi,their rate of slip-band refinement in V_(0.7)Cr_(0.3)CoNi 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.

关 键 词：Medium-entropy alloy Tensile property Solid-solution strength Strain-hardening rate Stacking fault energy 

分 类 号：TG139[一般工业技术—材料科学与工程]