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研究TA15钛合金在1050℃时,不同应变速率下变形过程中动态再结晶组织演变,讨论动态再结晶动力学、形核率和晶粒尺寸的演变规律。结果表明,随高低应变速率不同,存在两种类型的动态再结晶现象:连续动态再结晶和不连续动态再结晶。动力学分析应变速率为0.01,0.1,1s-1时,对应的动态再结晶稳态应变分别为1.26,1.57,2.93,说明增大应变速率则相应地提高稳态应变,在高应变速率条件下,往往难于达到稳态阶段。高应变速率下的形核率明显高于低应变速率下的形核率,且低应变速率下,较小幅度的增大应变速率就能使晶粒尺寸较大幅度下降;而在较高应变速率下,晶粒尺寸变化随应变速率改变较小。采用高应变速率及大应变下发生的连续动态再结晶可实现组织明显细化。
The dynamic recrystallization microstructure evolution of TA15 titanium alloy during deformation at different strain rates was studied at 1050 ℃. The dynamic recrystallization kinetics, nucleation rate and grain size evolution were studied. The results show that there are two types of dynamic recrystallization with different high and low strain rates: continuous dynamic recrystallization and discontinuous dynamic recrystallization. When the strain rates are 0.01, 0.1 and 1s-1, the corresponding dynamic recrystallization steady-state strains are 1.26, 1.57 and 2.93, respectively. It shows that increasing the strain rate increases the steady state strain correspondingly. Under the condition of high strain rate , It is often difficult to reach steady state. The nucleation rate at high strain rate is obviously higher than that at low strain rate, and at low strain rate, the smaller increase of strain rate can decrease the grain size greatly; while at higher strain Rate, the grain size changes with the strain rate changes smaller. Continuous dynamic recrystallization occurs at high strain rates and large strains to achieve significant grain refinement.