摘要
金属钴具有同素异构转变特性。为探究热轧工艺对高纯钴的微观组织及织构演变规律的影响,对纯度为99.99%(质量分数)的高纯钴进行500℃(高于同素异构转变温度)下的热轧,并采用电子背散射衍射(EBSD)技术对样品进行表征。结果表明:初始态板材由密排六方相(HCP相)和面心立方相(FCC相)构成,且以HCP相为主;HCP相晶粒的晶体取向较为集中,而FCC相晶粒的晶体取向较为分散;HCP相中的相变孪晶和FCC相中的退火孪晶含量较高。经过热轧,不同道次下的水冷板材中仍含有HCP相和FCC相,HCP相和FCC相在不同轧制板材中含量略有不同,但FCC相的相对含量均高于HCP相;HCP相晶粒的细化效果尤为显著。两相的小角度晶界含量较初始态大幅度上升,大角度晶界含量大幅度下降;轧制水冷板材中HCP相形成了特殊的择优取向,{0001}基面法向偏离ND方向朝向RD方向35°,且{10-12}取向较为分散;而FCC相呈现出较为随机的晶体取向特征。
The metal cobalt has the characteristics of isomeric transformation(from high temperature FCC phase to low temperature close packed hexagonal phase).In order to explore the influence of hot rolling process on the microstructure and texture evolution of high-purity cobalt,the cobalt with high-purity of 99.99%(mass fraction)was hot rolled at 500℃(higher than the isomerization temperature),and the samples were characterized by electron back-scattered diffraction(EBSD).The results show that the initial plate is composed of HCP phase and FCC phase,and HCP phase is the main phase.The crystal orientation of HCP phase is more concentrated,whereas FCC phase is more dispersed.The percentage of phase transformation twin in HCP phase and annealing twin in FCC phase are higher.After hot rolling,there are still HCP phase and FCC phase in the water-cooled plates with different passes.The percentage of HCP phase and FCC phase in different rolled plates is slightly different.The relative percentage of FCC phase is higher than that of HCP phase.The refining effect of HCP phase is particularly significant.Compared with the initial state,the percentage of small angle grain boundary of the two phases increased dramatically,whereas the percentage of large angle grain boundary decreased greatly.The HCP phase in rolled water-cooled plate formed a special preferred orientation,i.e.,the normal direction of{0001}base plane deviated from ND direction to RD direction by 35°,and the{10-12}orientation was more dispersed whereas the FCC phase showed a more random crystal orientation.
作者
李震
宋克睿
韩彦鹏
肖柱
贺昕
陈志永
LI Zhen;SONG Kerui;HAN Yanpeng;XIAO Zhu;HE Xin;CHEN Zhiyong(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Grikin Advanced Materials Co.,Ltd.,General Research Institute for Nonferrous Metals,Beijing 100088,China)
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2020年第4期8-15,共8页
Materials Science and Technology
基金
国家重点研究与发展计划项目(2017YFB0305500).
关键词
热轧
高纯钴
HCP相
FCC相
显微组织
织构
hot rolling
high purity cobalt
HCP phase
FCC phase
microstructure
texture
作者简介
李震(1993-)男,硕士研究生;肖柱(1983-)男,副教授,博士生导师;通信作者:陈志永(1970-),男,教授,博士生导师,E-mail:czysh@netease.com。
