Role of grain boundary character on Bi segregation-induced embrittlement in ultrahigh-purity copper  

作　　者：Y.X.Hua K.X.Song H.T.Liu J.W.Wang C.M.Zhang Y.J.Zhou B.Pang J.T.Song J.L.He H.L.Zhao 

机构地区：[1]School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471023,China [2]Henan Academy of Sciences,Zhengzhou 450000,China [3]Henan Key Laboratory of Advanced Conductor Materials,Zhengzhou 450046,China [4]Provincial and Ministerial Co-construction of Collaborative Innovation Center of Nonferrous New Materials and Advanced Processing Technology,Luoyang 471023,China [5]Center of Electron Microscopy and State Key Laboratory of Silicon Materials,School of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,China [6]College of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001,China

出　　处：《Journal of Materials Science & Technology》2023年第28期52-61,共10页材料科学技术（英文版）

基　　金：the National Natu-ral Science Foundation of China(Nos.52071133,51904090 and 52071284);the Henan Province Science and Technology Tackling Key Problems Project(No.222102230001);the Henan Province Young Talent Lifting Engineering Project(No.2021HYTP018);the Central Plain Scholar Workstation Project(No.224400510025);the Key R&D projects of Henan Province(No.221111230600).

摘　　要：Bismuth(Bi),as an impurity element in copper and copper-based alloys,usually has a strong tendency of grain boundary(GB)segregation,which depends on the GB characters.However,the influence of such a segregation on the properties of ultrahigh-purity copper has been rarely reported and the exact structural arrangements of Bi atoms at different GBs remain largely unclear.In this study,we investigated the influ-ence of trace amounts of Bi(50-300 wt ppm)on the ductility of an ultrahigh-purity copper(99.99999%)in the range of room temperature to 900°C.The tensile results show that the addition of Bi seriously damages the ductility of the ultrahigh-purity copper at temperatures of 450-900°C,which is due to the GB segregation of Bi.On this basis,such a segregation behavior at different types of GBs,including high and low angle GBs(HAGBs/LAGBs),and twin boundaries(TBs),via the scanning electron microscope-electron backscattered diffraction(SEM-EBSD)and aberration-corrected scanning transmission electron microscope(AC-STEM)investigations,combined with the first-principles calculations were systematically studied.The atomistic characterizations demonstrate an anisotropic Bi segregation,where severe enrich-ment of Bi atoms typically occurs at the HAGBs,while the absence of Bi adsorption prevails at LAGBs or TBs.In particular,the segregated Bi at random HAGBs exhibited the directional bilayer adsorption,while the special symmetrical7 HAGB presented a unique Bi-rich cluster superstructure.Our findings pro-vide a comprehensive experimental and computational understanding on the atomic-scale segregation of impurities in metallic materials.

关 键 词：Grain boundary character EMBRITTLEMENT Bi segregation Atomic configuration Ultrahigh-purity copper 

分 类 号：TG146.11[一般工业技术—材料科学与工程] TB383.1[金属学及工艺—金属材料]