不同定向凝固速率下Cu-2.5%Cr合金中带状组织的形成机理  

Formation Mechanism of Band-like Structure in Cu-2.5%Cr Alloy at Various Rates of Directional Solidification

作　　者：朱靖 李勇 王莹 李焕 赵亚茹 ZHU Jing;LI Yong;WANG Ying;LI Huan;ZHAO Yaru(Institute of Engineering Research,Jiangxi University of Science and Technology,Ganzhou 341000)

机构地区：[1]江西理工大学工程研究院,赣州341000

出　　处：《材料导报》2019年第2期309-313,共5页Materials Reports

基　　金：国家自然科学基金(51261007;51561007);江西省科技厅发明专利产业化重点项目(20161BBM26036);江西理工大学清江青年英才支持计划(JXUSTQJBJ2017005)~~

摘　　要：利用OM、SEM和EDS研究了定向凝固速度对Cu-2. 5%Cr合金中带状组织形貌和成分偏析的影响,并对不同形态的带状组织的形成机制进行了分析。结果表明:在5～50μm/s的定向凝固速率下,Cu-2. 5%Cr合金会产生平界面与共晶、胞状组织与共晶、柱状树枝晶与共晶三种不同形态的带状组织。这是由于凝固速率达到了平/胞转换临界速率以及胞/枝转换临界速率。带状组织的形成伴随着大量的溶质扩散与偏析,随着定向凝固速率的增大,带状组织中成分偏析增大,且带状组织愈加清晰。The impact of directional solidification rate on the morphology and composition segregation of band-like structures in Cu-2.5%Cr alloy were investigated by means of OM,SEM and EDS.The formation mechanism of band-like structures with diverse morphology was analyzed as well.The results showed that three different forms of band-like structures including:flat interface and eutectic,cell structure and eutectic,columnar dendrites and eutectic would be generated in the Cu-2.5%Cr alloy,at the directional solidification rates of 5-50 m/s.This was because the solidification rate reached the critical rate of flat/cell transition and the critical rate of cell/branch transition.The formation of band-like structure was accompanied by a large amount of solute diffusion and segregation.With the increase of directional solidification rate,the segregation of band-structure was enhanced,and the band-like structure became more distinct.

关 键 词：定向凝固 Cu-2.5%Cr合金 带状组织 凝固速率 成分偏析 

分 类 号：TG146[一般工业技术—材料科学与工程]