Microstructure and mechanical properties of as-cast(CuNi)100-xCox medium-entropy alloys  

作　　者：Zhi-yong Yang Wei-ping Chen Liang-yan Hao Chen-liang Chu Da-hai Zeng Wei Xiong Zhi-qiang Fu 

机构地区：[1]Guangdong Key Laboratory for Advanced Metallic Materials Processing,South China University of Technology,Guangzhou 510640,China [2]Physical Metallurgy and Materials Design Laboratory,Department of Mechanical Engineering and Materials Science,University of Pittsburgh,Pittsburgh,PA,15261,USA [3]National Engineering Research Center of Near-net-shape Forming for Metallic Materials,South China University of Technology,Guangzhou 510640,China

出　　处：《China Foundry》2022年第6期511-518,共8页中国铸造（英文版）

基　　金：supported by the Key-Area Research and Development Program of Guangdong Province(Grant No.2018B090905002);the National Natural Science Foundation of China(Grant No.52103360);the Basic Research Foundation of Guangzhou City(Grant No.201804020071).

摘　　要：Microstructure and mechanical properties of non-equiatomic(CuNi)_(100-x)Co_(x)(x=15,20,25 and 30,at.%)medium-entropy alloys(MEAs)prepared by vacuum arc-melting were investigated.Results show that all the as-cast MEAs exhibit dual face-centered cubic(fcc)solid-solution phases with identical lattice constant,showing typical dendrite structure consisting of(Ni,Co)-rich phase in dendrites and Cu-rich phase in inter-dendrites.The positive enthalpy of mixing among Cu and Ni-Co elements is responsible for the segregation of Cu.With the increase of Co content,the volume fraction of(Ni,Co)-rich phase increases while the Cu-rich phase decreases,resulting in an increment of yield strength and a decrement of elongation for the(CuNi)_(100-x)Co_(x) MEAs.Nano-indentation test results show a great difference of microhardness between the two fcc phases of the MEAs.The measured microhardness value of the(Ni,Co)-rich phase is almost twofold as compared to that of the Cu-rich phase in all the(CuNi)_(100-x)Co_(x) MEAs.During the deformation of the MEAs,the Cu-rich phase bears the main plastic strain,whereas the(Ni,Co)-rich phase provides more pronounced strengthening.

关 键 词：medium-entropy alloys microstructure mechanical properties nano-indentation 

分 类 号：TG146.11[一般工业技术—材料科学与工程]