Effects of inter-layer remelting frequency on the microstructure evolution and mechanical properties of equimolar CoCrFeNiMn high entropy alloys during in-situ powder-bed arc additive manufacturing(PBAAM)process  

作　　者：Jun Wang Yao Lu Fanghui Jia Wenzhen Xia Fei Lin Jian Han Ruichao Wang Zengxi Pan Huijun Li Zhengyi Jiang 

机构地区：[1]School of Mechanical Materials,Mechatronic and Biomedical Engineering,University of Wollongong,Wollongong,New South Wales 2522,Australia [2]School of Metallurgical Engineering,Anhui University of Technology,Maanshan 243000,China [3]Department of Structure and Nano-/Micromechanics of Materials,Max-Planck-Institut für Eisenforschung GmbH,Düsseldorf 40237,Germany [4]Faculty of Intelligent Manufacturing,Wuyi University,Guangdong 529020,China

出　　处：《Journal of Materials Science & Technology》2022年第18期90-104,共15页材料科学技术（英文版）

基　　金：financially supported by the China Scholarship Council (CSC)(No. 201606080014);the University of Wollongong(UOW);the Electron Microscopy center of UOW (EMC)

摘　　要：An equiatomic CoCrFeNiMn High Entropy Alloy(HEA)was in-situ deposited by the powder-bed arc ad-ditive manufacturing(PBAAM)process for the first time.Comparative research was conducted on the evolution of phase,crystallographic orientation,dislocation morphology,precipitation,and mechanical performance with the accumulation of inter-layer remelting times.The experimental outcomes mani-fested that the PBAAMed CoCrFeNiMn HEA consists of a stable solid-solution FCC structure,with de-creased lattice parameter but slightly increased(full width at half maximum)FWHM as the accumulation of the inter-layer remelting.The{001}<100>cube texture with a weakened texture intensity was de-tected with an increment of inter-layer remelting frequency from once to 5 times,yet it was transformed into{011}<100>Goss texture with a further increase to 7 times.Additionally,the mean grain diameter distinctly decreased,while the volume fraction of(low angle grain boundaries)LAGBs and dislocation density remarkably added up as the accumulated inter-layer remelts.Predominant cellular substructure generated in all process conditions and could be easily differentiated by elemental segregation.Both theσand M 23 C 6 Cr-rich precipitates in nano-scale and submicron MnS precipitate were detected on the grain boundaries of the PBAAMed deposited components,with a rather sparse distribution.Speaking of mechanical performance,the YS,UTS,and hardening rate are generally increased while the UE is grad-ually decreased as increased inter-layer remelting times.The studied PBAAMed CoCrFeNiMn HEA pos-sesses comparable mechanical performances with the counterparts of laser-deposited and as-cast ones.The strengthening mechanisms of the studied material are predominantly the grain boundary strength-ening and dislocation strengthening.This investigation would be a valuable resource in the research field of fabricating HEA alloys with acceptable microstructure and properties using the PBAAM method.

关 键 词：CoCrFeNiMn HEA Powder-bed arc additive manufacturing (PBAAM) Microstructure Phase Mechanical properties 

分 类 号：TG139[一般工业技术—材料科学与工程]