The microstructure evolution and its effect on flow stress of TC17 alloy during deformation in the α+β two-phase region were investigated via microstructure characterization and isothermal compression tests. Results showed that the spheroidized rate ofα phase at 820 and 850 ℃ slightly increased with increasing strain. With increasing deformation temperature, the spheroidized rate of α phase showed a slight increasing trend, but the volume fraction of α phase significantly decreased. The flow stress at 780 ℃ and 1 s-1 decreased continuously and steady state condition was not achieved up to strain of 1.2 due to dislocation annihilation and αlamellae rotation. Under this condition, the dynamic spheroidization was retarded. At the deformation temperatures of 820 and 850 ℃, and a strain rate of 1 s-1, a steady state flow stress was observed at strains above 0.8 due to the balance between work hardening and dynamic softening. The dynamic softening was attributed to the α lamellae rotation, dynamic recovery and a little spheroidization.%基于显微组织表征和等温热模拟压缩试验,研究TC17合金在 α+β 两相区变形时的显微组织演变及其对流动应力的影响.研究表明:当变形温度为820和850℃时,随着应变的增加,α 相的球化率略微增加;随着变形温度的升高,α 相的球化率略微增加,但是 α 相的体积分数明显减小.当变形温度为780℃、应变速率为1 s-1时,流动应力呈减小趋势;当应变为1.2时,由于位错湮没和 α 片层转动,流动应力未达到稳定状态.当变形温度为820和850℃、应变速率为1 s-1、应变大于0.8时,由于加工硬化和动态软化的平衡作用,流动应力呈稳定状态.合金动态软化归因于 α 片层转动、动态回复和轻微的球化.
展开▼
