Ti2AlNb板材的热拉伸行为和微观组织演化机理  

Hot tensile behavior and microstructure evolution mechanism of Ti2AlNb sheet

作　　者：武永 王东君 范荣磊 刘志强 刘钢[3,4] Wu Yong;Wang Dongjun;Fan Ronglei;Liu Zhiqiang;Liu Gang(Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;National Key Laboratory for Precision Hot Processing of Metals,Harbin Institute of Technology,Harbin 150001,China;Institute of High Pressure Fluid Forming,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]南京航空航天大学机电学院,江苏南京210016 [2]南京航空航天大学,江苏南京210016 [3]哈尔滨工业大学金属精密热加工国家级重点实验室,黑龙江哈尔滨150001 [4]哈尔滨工业大学流体高压成形技术研究所,黑龙江哈尔滨150001

出　　处：《稀有金属材料与工程》2020年第6期1825-1833,共9页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(51805256);High-level Personnel of Special Support Program(W02020239)。

摘　　要：通过高温拉伸试验研究了Ti-22Al-24.5Nb-0.5Mo合金在温度范围为910~1040℃、应变速率为0.0001~0.1 s-1条件下的高温变形行为。建立了B2/β+O、α2+B2/β+O和α2+B2/β3个不同相区的Arrhenius方程,并通过多种微观组织观察技术研究了微观组织演化机理。结果表明:在B2/β+O、α2+B2/β+O和α2+B2/β3个相区的激活能分别为759.43,516.7和438.59 kJ/mol。微观组织演化主要是O相晶粒的动态再结晶和B2/β相晶粒的动态回复,在B2/β+O相区的软化机制是片层O相晶粒的球化,而在α2+B2/β+O相区的软化机制是B2/β相晶粒的动态再结晶及局部剪切带的形成。The hot tensile behavior of Ti-22Al-24.5Nb-0.5Mo(at%) alloy was investigated by the hot tensile tests in the temperature range of 910~1040 °C and strain rate range of 0.0001~0.1 s-1. The Arrhenius equations were calculated at the three different phase fields and the microstructure evolution mechanisms were studied by microstructure observation. The results show that the activation energies are 759.43, 516.71 and 438.59 k J/mol at B2/β+O, α2+B2/β+O and α2+B2/β phase fields, respectively. The microstructure evolution is dominated by dynamic recrystallization of O-phase and dynamic recovery of B2/β phase grains, and the softening mechanism is the globularization of O lamellar grains at B2/β+O phase field, while the softening mechanism is dynamic recrystallization and shear bands of the B2/β-phase grains at α2+ B2/β+O phase field.

关 键 词：Ti2AlNb合金 高温拉伸 组织演变 Arrhenius方程 

分 类 号：TG146.23[一般工业技术—材料科学与工程]