Strengthening mechanisms analysis and tailoring of bimodal grain structures for enhanced strength in CoCrFeMnNi high-entropy alloys  

作　　者：Jaesoung Lee Seulgi Kim Taehyun Kwon Young II Kim Suyeon Kim Sung Ho Song Bin Lee Dongju Lee 

机构地区：[1]Department of Urban,Energy,and Environmental Engineering,Chungbuk National University,Cheongju 28644,Republic of Korea [2]Division of Advanced Materials Engineering,Kongju National University,Chungnam 330-717,Republic of Korea [3]Department of Advanced Materials Engineering for Information and Electronics,Integrated-Education Institute for Frontier Science and Technology(BK21 Four),Kyung Hee University,Yongin17104,Republic of Korea

出　　处：《Rare Metals》2024年第8期3893-3903,共11页稀有金属（英文版）

基　　金：financially supported by the Ministry of Trade,Industry&Energy (MOTIE,Korea)(No.20011520);Korea Institute of Energy Technology Evaluation and Planning (KETEP)(No.20217510100020);the Commercialization Promotion Agency for R&D Outcomes (COMPA)(No.1711175258)。

摘　　要：The CoCrFeMnNi high-entropy alloys(HEAs)with a(face-centered cubic) FCC structure has garnered considerable attention for its exceptional ductility and strain hardening ability.However,its yield strength is insufficient for structural applications.In this study,strengthening mechanisms in these HEAs were investigated to gain insight into the mechanical properties according to alloy powder size.Moreover,we present a novel approach to achieve both high strength and high ductility through the creation of a bimodal structure consisting of both coarse and fine grains via gas atomization and spark plasma sintering processes.A bimodally structured HEA prepared with a mass ratio of 2:8 between coarse particles(75-106 μm) and fine particles(≤25 μm)yielded optimal results,with a strength of 491.95 MPa and elongation of 19.64%.This strength value represents an~41% increase compared with the sample that displayed a fine single microstructure(347.08 MPa for yield strength).The strength enhancement was attributed to the prevention of plastic deformation initiation from the fine particles during deformation.This innovative approach to the creation of HEAs with bimodal structures shows promise for various applications,such as structural components that require a combination of high strength and high ductility.

关 键 词：High-entropy alloys CrCoFeMoNi BIMODAL Gas atomization Mechanical properties 

分 类 号：TG139[一般工业技术—材料科学与工程]