【摘要】 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。更多还原

【Abstract】 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 stressstrain 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.更多还原