Effect of Zr on phase separation,mechanical and corrosion behavior of heterogeneous CoCrFeNiZr_(x) high-etropy alloy  

作　　者：Wu Qi Wenrui Wang Xiao Yang Lu Xie Jiaming Zhang Dongyue Li Yong Zhang 

机构地区：[1]School of Mechanical Engineering,University of Science and Technology Beijing,Beijing 100083,China [2]Key Laboratory of Fluid Interaction with Material,Ministry of Education,Beijing 100083,China [3]Key Laboratory of Cryogenics,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing 100190,China [4]State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China

出　　处：《Journal of Materials Science & Technology》2022年第14期76-85,共10页材料科学技术（英文版）

基　　金：supported by the National Key R&D Program of China(Grant No.2020YFA0405700);the Inner Mongolia Science and Technology Major Project(No.2020ZD0011)。

摘　　要：CoCrFeNi high entropy alloy(HEA)has attracted extensive attention due to its excellent corrosion resistance,but the low strength limits its engineering application prospects.In order to develop CoCrFeNi based HEAs with high strength,ductility and corrosion resistance,the effects of Zr content on the microstructure,mechanical properties and corrosion resistance of heterogeneous CoCrFeNiZr_(x)(x=0,0.25,0.5 and 1)HEAs were investigated in this work.The results indicate that the increase of Zr content can significantly affect the phase stability of the alloy,and promote the formation of intermetallic compounds(Ni_(7)Zr_(2)and/or Laves phase)and the transformation of solid solution from face-centered cubic(FCC)structure(x=0,0.25 and 0.5)to body-centered cubic(BCC)structure(x=1).Reasonable control of the Zr content can endow the alloy excellent comprehensive properties.Especially,for CoCrFeNiZr_(0.25) alloy,composed of FCC matrix and a small amount of Ni_(7)Zr_(2)phases,the yield strength(~655 MPa)is increased by nearly four times higher than that of Zr-free alloy,and it also has good ductility(fracture stain>50%).Meanwhile,the corrosion resistance of CoCrFeNiZr_(0.25) alloy is better than that of SS304.The EIS results show that the addition of Zr reduces the stability of the passive film on the alloy,which can be related to the content of the beneficial oxide in the passive film and the thickness of the passive film through XPS analysis.Moreover,the work functions of different phases in CoCrFeNiZr_(x)alloys were obtained by firstprinciples calculations,which further confirmed the selective corrosion mechanism of the CoCrFeNiZr_(x) alloy combining the experimental results.

关 键 词：High-entropy alloy Microstructure Corrosion resistance FIRST-PRINCIPLES Work function 

分 类 号：TG139[一般工业技术—材料科学与工程]