Effects of dispersoid preforming via multistep sintering of oxide dispersion-strengthened CoCrFeMnNi high-entropy alloy  

作　　者：SeungHyeok Chung Ji Ho Shin Ho Jin Ryu 

机构地区：[1]Department of Nuclear and Quantum Engineering,Korea Advanced Institute of Science and Technology(KAIST),Daejeon 34141,Republic of Korea [2]Central Research Institute,Korea Hydro and Nuclear Power Co.,Ltd.,(KHNP),Daejeon 34101,Republic of Korea

出　　处：《Journal of Materials Science & Technology》2023年第9期187-200,共14页材料科学技术（英文版）

基　　金：supported by the National Research Foundation of the Ministry of Science and ICT(MSIT)of the Republic of Korea(Nos.2021R1A2C2014025,2020R1A5A6017701,and 2022M3H4A1A02076759)。

摘　　要：Dispersoid formation and microstructural evolution in an oxide dispersion-strengthened CoCrFeMnNi high-entropy alloy(HEA)using a newly designed multistep sintering process are investigated.The proposed multistep sintering consists of a dispersoid preforming heat treatment of as-milled 0.1 wt%Y_(2)O_(3)-CoCrFeMnNi high-entropy alloy powders at 800℃,followed by sintering at 800–1000℃ under uniaxial pressure.In the conventional single-step sintered bulk,the coarsened BCC Y_(2)O_(3)dispersoids mainly form with an incoherent interface with the HEA matrix.In contrast,finer FCC Y_(2)O_(3)dispersoids,an atypical form of Y_(2)O_(3),are formed in the matrix region after multistep sintering.Nucleation of FCC Y_(2)O_(3)disper-soids is initiated on the favorable facet,the{111}plane of the austenitic matrix,with the formation of a semi-coherent interface with the matrix during the dispersoid preforming heat treatment and it maintains its refined size even after sintering.It is found that dispersoid preforming prior to sintering appears promising to control the finer dispersoid formation and refined grain structure.

关 键 词：Oxide dispersion strengthening High-Entropy alloy Multistep sintering Dispersoid preforming Microstructure evolution Interfacial structure 

分 类 号：TG139[一般工业技术—材料科学与工程]