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采用gleeble-1500热模拟试验机及分离式霍普金森压杆技术,对TC6钛合金试样进行高温准静态(0.01s-1)压缩试验及室温高应变率(103s-1)剪切试验,通过光学显微镜及透射电镜对比研究2种变形条件下材料微结构演化特点。结果表明:在2种变形条件下材料微结构演化显著不同。在高温准静态条件下变形时,TC6钛合金微结构演化经历了4个阶段:等轴状α相变形为板条状→板条状α相断裂,同时出现动态再结晶晶粒→动态再结晶晶粒长大→发生α/β相变;在高应变率加载条件下变形时,TC6钛合金微结构演化经历了3个阶段:等轴状α相变形为板条状→位错的快速运动,板条状α相变形为更为细长狭窄的长条状→长条状α相断裂,同时出现少量动态再结晶晶粒;在2种变形条件下,TC6钛合金均发生了动态再结晶,但高温准静态下,动态再结晶晶粒较多且发生长大,尺寸为3～5μm,而高应变率加载条件下形成的动态再结晶晶粒较少且没有长大,尺寸为0.1～0.2μm。
The high temperature quasi-static (0.01s-1) compression test and room temperature high-strain rate (103s-1) shear test of TC6 titanium alloy were carried out by using gleeble-1500 thermal simulator and split Hopkinson pressure bar technique. The microstructural evolution characteristics under two kinds of deformation conditions were studied by optical microscope and transmission electron microscope. The results show that the microstructural evolution of the material under the two deformation conditions is significantly different. Under the condition of high temperature and quasi-static deformation, the microstructure evolution of TC6 titanium alloy has gone through four stages: the equiaxed α phase transforms to lath-bar → lath α-phase fracture, and the dynamic recrystallization grain → dynamic recrystallization Grain growth → α / β transformation occurs. At deformation under high strain rate loading, the microstructure evolution of TC6 titanium alloy undergoes three stages: the equiaxed α phase transforms into lath → rapid movement of dislocation , The lath-shaped α-phase deformation is a more slender and narrow long-bar-shaped α-phase fracture, and a small amount of dynamic recrystallization grains appear at the same time. Under the two deformation conditions, the dynamic recrystallization of TC6 titanium alloy occurs However, under the condition of high temperature quasi-static, the number of dynamic recrystallization grains increases and the size grows to 3 ~ 5μm. However, the dynamic recrystallization grains formed under the conditions of high strain rate load are few and do not grow, 0.2 μm.