Improving in plasticity of orthorhombic Ti_2AlNb-based alloys sheet by high density electropulsing  

高密度脉冲电流处理对Ti_2AlNb基合金板材的增塑作用(英文)

作　　者：宋辉[1] 王忠金[2] 赫晓东[1] 

机构地区：[1]哈尔滨工业大学航天学院,哈尔滨150001 [2]哈尔滨工业大学材料科学与工程学院,哈尔滨150001

出　　处：《Transactions of Nonferrous Metals Society of China》2013年第1期32-37,共6页中国有色金属学报（英文版）

基　　金：Project(50875061) supported by the National Natural Science Foundation of China;Project(20092302110016) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China

摘　　要：In order to optimize the ductility of orthorhombic Ti2AlNb-based alloys sheet,Ti22Al27Nb sheet was treated by high density electropulsing（J max =6.80 7.09 kA/mm2,tp =110 μs） under ambient condition.Microstructures were observed by SEM,and the tensile properties were also studied using uniaxial tension tests.The experimental results show that electropulsing can refine the microstructures of Ti22Al27Nb sheets.The specimen with the fine and homogeneous microstructures has good plasticity,and its elongation reaches 19.4%.The mechanism about the effect of electropulsing treatment on the microstructure of Ti22Al27Nb sheets was discussed.It was thought that the increase in nucleation rate during phase transformation and a very short treating time were regarded as the main reasons of producing smaller grains and increase in the plasticity by electropulsing.为了优化Ti22Al27Nb基合金板材的塑性,研究了高密度脉冲电流(Jmax=6.80～7.09kA/mm2,tp=110μs)处理对Ti22Al27Nb合金板材力学性能和组织的影响。应用扫描电子显微镜(SEM)观察了试样的微观组织和形貌变化,应用单向拉伸试验对不同状态试样的力学性能进行了测试。结果表明,高密度脉冲电流处理能够细化Ti22Al27Nb合金板材的晶粒,促进塑性的提高。具有细小而均匀显微组织的试样表现出最好的塑性,其伸长率可达到19.4%。对晶粒细化的机制进行了分析,相变过程中形核率的加快和极短的脉冲电流处理时间是晶粒细化的主要原因。

关 键 词：Ti2AlNb-based alloys electropulsing treatment PLASTICITY grain refinement microstructure nucleation rate phase transformation 

分 类 号：TG335.12[金属学及工艺—金属压力加工]