高Nb-TiAl合金在等温过程中相变动力学研究  

Phase transformation kinetics of high Nb-TiAl alloy during isothermal treatments

作　　者：李莹 田淑侠 樊江磊 王艳 刘建秀 Li Ying;Tian Shuxia;Fan Jianglei;Wang Yan;Liu Jianxiu(Institute of Mechanical and Electrical Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,Henan,China)

机构地区：[1]郑州轻工业大学机电工程学院,河南郑州450002

出　　处：《钢铁钒钛》2022年第5期59-64,共6页Iron Steel Vanadium Titanium

基　　金：河南省科技攻关项目(202102210451,202102210446)。

摘　　要：采用原位热膨胀法较为系统地研究了高Nb-TiAl合金的等温相变动力学。结果表明:高Nb-TiAl合金α→α等温相变过程中,其“鼻尖”温度为1 170℃,此温度下α相的转变速度最快,且该相的形成呈“S”曲线。基于热膨胀曲线,获取了等温过程中相应的JMA等温相变动力学方程,基于JMA方程,通过对数拟合相转变分数-时间曲线,获取高Nb-TiAl合金等温相变动力学Avrami指数n和温度常数K,建立了高Nb-TiAl合金温度-时间-相转变的定量关系TTT曲线(Time-Temprature-Transformation);并揭示了合金扩散控制的相变动力学机制。The isothermal phase transformation kinetics of α→α at the temperature 1 140-1 200 ℃ in high Nb-TiAl alloy were systematically studied by in-situ thermal expansion method. The results show that during the α→α isothermal phase transformation of high Nb-TiAl alloy, the “nose tip” temperature of α→α phase transformation is 1 170 ℃, and the formation of α phase presents an “S” curve.Based on the thermal expansion curve, the corresponding JMA isothermal phase transformation kinetics equation during the isothermal process was obtained. On the basis of the JMA equation, the Avrami exponent n and temperature constant K of isothermal phase transformation of high Nb-TiAl alloy were obtained by logarithmic fitting the fractional time curve of phase transformation. Based on the results of thermal expansion measurement, the time-temperature-transformation diagram(TTT diagram) was plotted for high Nb-TiAl alloy. The phase transformation kinetics mechanism of high Nb-TiAl alloy controlled by diffusion was revealed.

关 键 词：高Nb-TiAl合金 原位热膨胀法 等温相变 动力学 

分 类 号：TF823[冶金工程—有色金属冶金] TG146.2[一般工业技术—材料科学与工程]