Strengthening and deformation mechanism of high-strength CrMnFeCoNi high entropy alloy prepared by powder metallurgy
作者机构：Faculty of Materials Science and EngineeringKunming University of Science and TechnologyKunming 650093China Laboratory for MicrostructuresInstitute of MaterialsShanghai UniversityShanghai 200444China School of MechanicalElectrical&Information EngineeringShandong UniversityWeihai 264209China College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Erich Schmid Institute of Materials ScienceAustrian Academy of SciencesJahnstraße 12Leoben A-8700Austria Department of Materials ScienceChair of Materials PhysicsMontanuniversität LeobenJahnstraße 12Leoben A-8700Austria Adjunct with National University of Science and Technology«MISiS»Leninsky Prosp.4Moscow 119049Russia
出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)
年 卷 期：2023年第132卷第1期
页 面：119-131页
核心收录：
学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学]
基 金：supported by the National Natu-ral Science Foundation of China(Nos.52061021,51861016,and 51871132) the Science and Technology Major Project of Yun-nan Province(Nos.202202AG050004,202002AB080001) the Young and Middle-Aged Academic and Technical Leaders Reserve Talent Project(No.202005AC160039) support by the Ministry of Science and Higher Educa-tion of the Russian Federation in the framework of the Increase Competitiveness Program of NUST«MISiS»(No.K2-2020-046) financial support from the China Scholarship Council(CSC,No.201906220226).
主 题：High entropy alloy Powder processing Grain refinement Precipitation strengthening Deformation twinning
摘 要：Multiphase CrMnFeCoNi high-entropy alloys(HEAs)were prepared by a powder metallurgy process com-bining mechanical alloying(MA)and vacuum hot-pressing sintering(HPS).The single-phase face-centered cubic(FCC)HEA powder prepared by MA was sintered into a bulk HEA specimen containing FCC phase matrix along with precipitated M 23 C 6 phase and nanoscaleσphase particles.When the sintering temper-ature was 1223 K,the ultimate strength reaches 1300±11.6 MPa,and the elongation exceeds 4%±0.6%.Microstructural characterization reveals that the formation of nanoscale particles and deformation twins play critical roles in improving the strain hardening(SH)ability.Prolonging the MA time promoted the formation of the precipitated phase and enhanced the SH ability by increasing the number of precip-itated particles.The SH capacity increases significantly with increasing sintering temperature,which is attributed to a significant enhancement in the twinning capacity due to grain growth and the reduced number ofσphase particles.Through systematic studies,the planar glide of dislocations was found to be the main mode of deformation,while deformation twinning appeared as an auxiliary deformation mode when the twinning stress was reached.Although the formation of precipitates leads to grain bound-ary and precipitation strengthening effects,crack initiation is more prominent owing to increased grain boundary brittleness around the precipitated M 23 C 6 phase.The prominence of crack initiation is a contra-diction that must be reconciled with regard to precipitation strengthening.This work serves as a useful reference for the preparation of high-strength HEA parts by powder metallurgy.
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