(α2+γ)双态细晶高铌TiAl合金的热变形行为及其机制  

Hot deformation behaviors and mechanisms of high Nb containing TiAl alloys with refined(α2+γ)duplex microstructure

作　　者：杨光 左俊娴 杨肖肖 韩松松 白文鹏 李誉之 YANG Guang;ZUO Jun-xian;YANG Xiao-xiao;HAN Song-song;BAI Wen-peng;LI Yu-zhi(College of Mechanical and Electrical Engineering,Shaanxi University of Science&Technology,Xi′an 710021,China;Xi′an United Pressure Vessel Co.,Ltd.,Xi′an 710201,China)

机构地区：[1]陕西科技大学机电工程学院,陕西西安710021 [2]西安优耐特容器制造有限公司,陕西西安710201

出　　处：《陕西科技大学学报》2023年第3期138-146,共9页Journal of Shaanxi University of Science & Technology

基　　金：中国博士后科学基金项目(2021M693856);陕西省科技厅自然科学基金项目(2022JM-179,2021JQ-551)。

摘　　要：在Gleeble-1500D热模拟试验机上对(α2+γ)双态细晶高铌TiAl合金进行热压缩实验,研究了其热变形行为和变形机制.结果表明:不同变形条件下的应力-应变曲线均呈现“加工硬化-动态软化”的特征,并且峰值应力随着变形温度的升高和应变速率的降低逐渐减小.采用幂率方程对不同工艺参数下的应力指数n和表观激活能Q进行了计算,结合显微组织表征分析了该合金的变形机制.在低温高应变速率下合金的变形由位错蠕变机制主导,在高温低应变速率下合金的变形受位错蠕变和晶界滑动机制共同控制.In this work,hot deformation behaviors and deformation mechanisms of high Nb containing TiAl alloys with refined(α2+γ)duplex microstructure were investigated by hot compression experiments on Gleeble-1500D machine.Results showed that the stress-strain curves under different deformation conditions presented a characteristic of″work hardening-dynamic softening″,and peak stress decreased with the increase of deformation temperature and decrease of strain rate.The stress index n and apparent activation energy Q under different deformation conditions were calculated by power rate equation,and deformation mechanisms of the alloys were analyzed combined with microstructure characterization.Deformation of the alloys under low temperature and high strain rate was dominated by dislocation creep mechanism,while the deformation under high temperature and low strain rate was controlled by both dislocation creep and grain boundary sliding mechanisms.

关 键 词：高铌TIAL合金 热变形行为 显微组织 变形机制 

分 类 号：TG113.12[金属学及工艺—物理冶金]