α相尺寸对等轴TC4合金两相区热变形行为的影响  

Effect of α Grain Size on Deformation Behaviors of TC4 Titanium Alloy with Equiaxed Microstructure

作　　者：程明[1] 赵建国[2] 宋鸿武[1] 张士宏[1,2] 

机构地区：[1]中国科学院金属研究所,沈阳110016 [2]大连理工大学材料科学与工程学院,辽宁大连116024

出　　处：《航空材料学报》2009年第1期22-26,共5页Journal of Aeronautical Materials

摘　　要：对α相平均尺寸分别为6μm，12μm，20μm的等轴TC4合金在890～950℃，应变速率0．1—10s^-1范围进行等温热压缩实验，并研究了初始“相尺寸对合金高温变形行为的影响。微观组织和动力学分析表明，等轴TC4合金变形的热激活过程受相变和晶粒长大作用的综合影响，计算获得的激活能偏大。在初始α相尺寸较小（6μm）的情况下变形，晶粒易于吞并长大，使变形后的组织粗化；在初始α相尺寸增大（12μm）的情况下会促进相变过程的进行，获得的变形组织中α相尺寸较细小；初始α相尺寸进一步增大（20μm），则变形组织的晶粒尺寸基本不再发生变化。The deformation mechanism of TC4 alloy with different initial α sizes of 6μm, 12μm, 20μm respectively has been investigated by isothermal compression tests in a temperatures range 890 - 950℃ and strain rates range 0. 1 - 10s^-1. The results show that the effect of initial α size on flow stress is complicated and less significant compared to strain rate and temperature. Microstructure characterization and kinetic analysis show that the thermal activated deformation process of TC4 alloy is controlled by both phase transformation and grain growth. The calculated activation energy is much higher than the results reported. Small initial α size tends to aggregate and grow with a coarse grain size after deformation. With an initial α size of 12μm, phase transformation is improved and fine grain size is obtained after deformation. With initial α size increased to 20μm, slightly effect on grain size happened.

关 键 词：TC4合金 流动应力 α相尺寸 相变 激活能 晶粒长大 

分 类 号：TG115.6[金属学及工艺—物理冶金]