(中国船舶工业集团公司，洛阳 471039)
摘 要: 利用热模拟实验机对Ti30Nb13Zr0.5Fe(质量分数，%)医用钛合金在温度700～850 ℃、变形速率10−3～10 s−1范围内进行等温热压缩试验，观察变形后钛合金的显微组织，并根据动力学分析确定合金β相区热变形方程、应力指数n和激活能Q。结果表明： 温度变化不改变σ —ε曲线特征；应变速率对变形行为的影响较大， 为1～10 s−1时，出现流变不稳定性； 为10−2～1 s−1时，组织发生β相再结晶和动态回复；当θ＞800 ℃、 ＜10−2 s−1时，组织发生β相连续再结晶，导致晶粒粗化；合金β相区变形应力指数n和激活能Q分别为4.5和195 kJ/mol；综合考虑可热加工性和组织细化因素，温度为700～800 ℃、应变速率为10−3～10−1 s−1是良性热加工区域。
关键字: 医用钛合金；热压缩；流动应力；显微组织；变形机制
（Luoyang Ship Material Research Institute, Luoyang 471039, China）
Abstract:The hot deformation behaviors of Ti30Nb13Zr0.5Fe (mass fraction, %) alloy were studied by thermal-simulator in the temperature range of 700−850 ℃ and strain rate range of 10−3−10 s−1. The hot deformation equation, stress exponential n and deformation activation energy Q were established according to the dynamical analysis. The microstructures were observed by optical microscopy. The results indicate that the variation of deformation temperature doesn’t change the characteristics of true stress—strain curves, but the variation of strain rate has crucial effect on the deformation behaviors. The instable flow happens at strain rate of 1−10 s−1, the dynamic recrystallization and dynamic recovery of β phase occur at strain rate of 10−2−1 s−1. And the continual recrystallization and grain coarsening occur at strain rate less than 10−2 s−1 and temperature higher than 800 ℃. The stress exponential n and deformation activation energy Q of β phase are 4.5 and 195 kJ/mol, respectively. Considering workability and microstructure refining, the optimum conditions of hot deformation for Ti30Nb13Zr0.5Fe alloy are the temperature range of 700−800 ℃ and strain rate range of 10−3−10−1 s−1.
Key words: biomedical titanium alloy; heat deformation; flow stress; microstructure; deformation mechanism
