Exceptional strength-ductility synergy of additively manufactured CoCrNi medium-entropy alloy achieved by lattice defects in heterogeneous microstructures

作     者：Jianying Wang Jianpeng Zou Hailin Yang Lijun Zhang Zhilin Liu Xixi Dong Shouxun Ji Jianying Wang;Jianpeng Zou;Hailin Yang;Lijun Zhang;Zhilin Liu;Xixi Dong;Shouxun Ji

作者机构：State Key Laboratory of Powder MetallurgyCentral South UniversityChangsha 410083China Light Alloy Research InstituteCollege of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China Brunel Centre for Advanced Solidification Technology(BCAST)Brunel University LondonUxbridgeMiddlesex UB83PHUnited Kingdom 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2022年第127卷第32期

页      面：61-70页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：the National Key Research and Development Program of China(No.2020YFB0311300ZL) the National Natural Science Foundation of China(No.52071343) 

主　　题：Medium-entropy alloys Selective laser melting Strength-ductility synergy Defects Microstructure 

摘      要：The selective laser melting(SLM)with subsequent cold rolling and annealing is used to produce high-density lattice defects and grain refinement in the CoCrNi medium-entropy alloys(MEAs).The superior comprehensive mechanical properties have been achieved in the as-SLMed CoCrNi alloy after rolling and *** as-SLMed alloys delivered the yield strength of 693.4 MPa,the ultimate tensile strength of 912.7 MPa and the fracture strain of 54.4%.After rolling with 70%reduction in thickness and annealing at 700℃for 2 *** yield strength,ultimate tensile strength and fracture strain reached 1161.6 MPa,1390.8 MPa and 31.5%,*** exceptional strength-ductility synergy is mainly attributed to the refined hierarchical microstructures with coarsening grains at a level of 30μm and ultrafine grains at a level of 1μm,and the heritage of dislocation-formed sub-grains and other lattice *** investigation demonstrates that the SLM with subsequent rolling and annealing is beneficial to fabricate high strength and ductile MEAs with single face-centered cubic(fcc)structure.