(中国科学院 金属研究所,沈阳 110016)
摘 要: 采用Gleeble-3800热模拟试验机对TB9钛合金进行等温压缩试验,变形温度分别为850和950 ℃,应变速率为1 s-1,真应变分别为0.3,0.5,0.7,0.9和1.2,研究应变对TB9合金热变形行为及显微组织的影响。结果表明:温度越高,流变应力越小;在较小应变下,显微组织主要发生动态回复,随着应变增大,动态回复、动态再结晶增强,同时,出现几何动态再结晶现象;变形温度为950℃时,合金易发生动态再结晶,但变形量不能过大,否则会形成粗大的再结晶晶粒,造成显微组织不均匀,合适的真应变为0.7~0.9。
关键字: TB9钛合金;热变形;应变;显微组织;动态再结晶
(Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)
Abstract:The effect of strains on hot deformation behavior and microstructure of TB9 titanium alloy were investigated by isothermal compression tests on a Gleeble-3800 thermomechanical simulator at deformation temperatures of 850 ℃ and 950 ℃, the strain rate of 1 s-1 and true strains of 0.3, 0.5, 0.7, 0.9 and 1.2, respectively. The results show that the flow stress decreases with increasing temperature. The microstructure undergoes dynamic recovery mainly at small strains. With strains increasing, dynamic recovery and dynamic recrystallization are enhanced and geometrical dynamic recrystallization occurs at high strains. At 950 ℃, dynamic recrystallization happens more easily but large recrystallization grains can be generated at high strains, which causes inhomogeneous microstructure. Beneficial true strains are 0.7-0.9 when TB9 alloy is deformed at 950 ℃ and 1 s-1.
Key words: TB9 titanium alloy; hot deformation; strain; microstructure; dynamic recrystallization