Introduction of nanotwins into nanoprecipitations strengthened CoCrNiMo_(0.2) alloy to achieve strength and ductility trade-off:A comparative research  

作　　者：Hao Zhang Ziyi Ren Yonggang Tong Yongle Hu Xixi Ji Lingwei Yang Kaiming Wang Jingzhong Fang Hui Chen Xiubing Liang 

机构地区：[1]College of Automotive and Mechanical Engineering,Changsha University of Science and Technology,Changsha 410114,China [2]Hypervelocity Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China [3]School of Civil Engineering,Changsha University of Science and Technology,Changsha 410111,China [4]National Institute of Defense Technology Innovation,Academy of Military Science PLA China,Beijing 100072,China

出　　处：《Journal of Materials Science & Technology》2023年第25期172-182,共11页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.92166105 and 52005053);the High-Tech Industry Science and Technology Innovation Leading Program of Hunan Province(No.2020GK2085);the Science and Technology Innovation Program of Hunan Province(No.2021RC3096).

摘　　要：Normal strengthening methods through precipitations and deformation obviously enhance the strength of metallic materials while resulting in the sacrifice of ductility,and synergistic improvement of strength and ductility is currently an urgent requirement.Herein we developed a cryogenic deformation combined with an annealing method to fabricate CoCrNiMo_(0.2) medium entropy alloy,which achieved an ultrahigh strength of 1.8 GPa with synergistic improvement in strength and ductility.Microstructure,mechanical performance,and strengthening mechanisms of the developed alloys were investigated compared with that prepared by the regular room temperature deformation method.It was found that high-density nanotwins were produced in CoCrNiMo_(0.2) MEA via cryogenic deformation.Fine grains,hard precipitations,and high volume fraction of nanotwins greatly strengthened the alloy,obtaining a yield and ultimate tensile strength of 1400 MPa and 1800 MPa.Ductility improvement of the developed alloy was mainly attributed to the production of deformation nanotwins due to the lower stacking fault energy,which greatly increases the dislocation storage ability,and thus,the ductility of the alloy was enhanced.

关 键 词：NANOTWINS Mechanical properties Deformation behavior Strengthening mechanisms 

分 类 号：TG139[一般工业技术—材料科学与工程]