Unveiling the unique bifunctionality of L12-structured nanoprecipitates in a FeCoNiAlTi-type high-entropy alloy  

作　　者：Jianyang Zhang Zhankun Zhao Qian Li Junhua Luan Chain-Tsuan Liu Yilu Zhao Tao Yang 

机构地区：[1]Department of Materials Science and Engineering,Mechanical Behavior Division of Shenyang National Laboratory for Materials Science,City University of Hong Kong,Hong Kong,China [2]School of Materials Science and Engineering,Harbin Institute of Technology,Shenzhen,China [3]Department of Mechanical Engineering,City University of Hong Kong,Hong Kong,China [4]Hong Kong Institute for Advanced Study,City University of Hong Kong,Hong Kong,China [5]Hong Kong Branch of National Precious Metals Material Engineering Research Centre(NPMM),City University of Hong Kong,Hong Kong,China

出　　处：《Advanced Powder Materials》2023年第3期21-27,共7页先进粉体材料（英文）

基　　金：supports from the National Natural Science Foundation of China(No.52101151);the Hong Kong Research Grant Council(RGC)(Grant No.CityU 21205621 and C1020-21G);the Shenzhen Science and Technology Program(Grant No.SGDX20210823104002016);the Harbin Institute of Technology(Shenzhen)thanks to thefinancial support from the National Natural Science Foundation of China(No.52101135)and the Shenzhen Science and Technology Program(Grant No.RCBS20210609103202012).

摘　　要：Nanoprecipitation strengthening has been widely adopted as an effective way to design high-strength alloys,which generally leads to the loss of ductility. Here we unveil the unique bifunctionality of L12-structurednanoprecipitates in a FeCoNiAlTi-type high entropy alloy , enabling the combined increase of tensile strength andductility. Results show that as-quenched precipitate-free matrix alloys undergo thermally-induced martensitetransformation and form the body-centered cubic martensite phase with limited tensile ductility. In strongcontrast, when introducing the dense coherent L12-type nanoprecipitates, the face-centered cubic matrix istemporarily stabilized, which in turn promotes the microbands-induced plasticity associated with stress-inducedmartensite transformation upon deformation. This allows us to achieve significantly improved work hardeningcapability and excellent plastic deformation stability at a high-strength level. These new findings reshape ourunderstanding of the precipitation strengthening and could provide useful guidance for developing highperformance alloys by regulating the coherent nanoprecipitate and martensitic phase transformation.

关 键 词：High-entropy alloys Precipitation strengthening Mechanical properties Deformation mechanisms Martensitic transformation 

分 类 号：TG1[金属学及工艺—金属学]