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.

Hyun Chung;Dae Woong Kim;Woo Jin Cho;Heung Nam Han;Yuji Ikeda;Shoji Ishibashi;Fritz K?rmann;Seok Su Sohn

Department of Materials Science and Engineering,Korea University,Seoul 02841,South Korea;Center for High Entropy Alloys,Pohang University of Science and Technology,Pohang 37673,South Korea;Department of Materials Science and Engineering and Research Institute of Advanced Materials,Seoul National University,Seoul 08826,South Korea;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;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;Department of Materials Science and Engineering,Delft University of Technology,Mekelweg,2,Delft 2628 CD,the Netherlands

材料科学技术（英文版）

[1]Hyun Chung;Dae Woong Kim;Woo Jin Cho;Heung Nam Han;Yuji Ikeda;Shoji Ishibashi;Fritz K?rmann;Seok Su Sohn-.Effect of solid-solution strengthening on deformation mechanisms and strain hardening in medium-entropy V1-xCrxCoNi alloys)[J].材料科学技术（英文版）,2022(13):270-280

xCrxCoNi,4Cr0,6CoNi,7Cr0,3CoNi,VCoNi

Effect,solid,solution,strengthening,deformation,mechanisms,strain,hardening,medium,entropy,V1,alloys,High,HEAs,MEAs,possess,Numerous,vestigations,have,been,conducted,its,impact,yield,however,are,limited,reports,regarding,relation,between,rate,In,addition,no,attempt,has,made,account,dislocation,mediated,plasticity,most,works,focused,twinning,transformation,induced,TWIP,TRIP,this,reveal,role,via,systematically,investigating,evolutions,structures,by,controlling,ratio,prototypical,Comparing,CrCoNi,slip,V0,was,superior,band,refinements,due,dynamic,Hall,Petch,effect,However,content,increased,fur,their,surpassed,that,Although,generally,accepted,conventional,results,higher,than,observed,latter,can,predominant,former,under,activated,huge,lowered,cross,activation,consequently,retarded,rearrangement,recovery,This,delay,decrease,therefore,overall,rich

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