TC2钛合金的高温热变形行为

对TC2钛合金的高温变形行为进行了有限元模拟和热压缩实验研究，使用有限元自洽模型模拟提高流动应力曲线修正精度，分析材料的应力应变曲线特征，得到其高温流动本构方程和激活能，并进行了光学显微镜观察研究其微观组织演变规律，发现在高温低应变速率下α相的球化程度较高。绘制出TC2钛合金的功率耗散图和热加工图，结合应变速率敏感系数m研究了受m值控制的不同变形机制，最终确定了TC2钛合金的最佳加工窗口：(I)760~825℃、0.007~0.024 s^-1；(II)850~900℃、0.018~0.37 s^-1；(III)900~950℃、1~10 s^-1，在此区间功率耗散因子较大，在材料变形过程中发生充分动态再结晶，试样的微观组织呈细小等轴状。

Hot Deformation Behavior of TC2 Titanium Alloy

The high temperature deformation behavior of TC2 Ti-alloy was investigated by means of finite element simulations and isothermal hot compression tests parallelly. Firstly, the characteristic stress-strain curves of TC2 were analyzed, and the high temperature constitutive equation and activation energy were acquired . Secondly, the microstructure evolution was observed with optical microscope. It was found that the globularization of α-phase is obvious at high temperature and low strain rate. Thirdly, the power dissipation and thermal processing map of TC2 Ti-alloy were drawn. And the deformation mechanism was characterized by strain rate sensitivity exponent m. Lastly, and the optimized processing window of TC2 Ti-alloy was determined as: (I) 760~825℃, 0.007~0.024 s^-1; (II) 850~900℃, 0.018~0.37 s^-1; and (III) 900~950℃, 1~10 s^-1. Within these ranges the power dissipation rate of TC2 Ti-alloy is significant and sufficient dynamic recrystallization occurs in the process of deformation.