TiH2基粉末冶金近α钛合金Ti-1100的热变形行为

Hot deformation behavior of near α titanium alloy Ti-1100 prepared by TiH2-based powder metallurgy

摘要:

通过热压缩试验，研究了TiH2基粉末冶金近α钛合金Ti-1100在973-1173K温度范围和0.01-1.0s-1应变速率范围内的热变形行为。建立了Arrhenius本构方程，计算出的热形变活化能为334.76 kJ / mol。通过修改函数计算了温度灵敏度（θ），确定了应变率灵敏度（m）。根据温度灵敏度、应变率灵敏度和应变率为0.5时的显微组织分析结果，对热加工条件进行了分析。结果表明，在应变率为0.01s-1和1s-1，在整个温度范围内，出现了失稳区，而在1135K&0.29s-1至1173K&0.76s-1、1040&0.33s-1至1096K&0.6s-1的范围内获得了最佳的热加工条件。此外，微观结构分析表明，在0.01-0.1s-1的应变速率条件下发生了动态再结晶（DRX），而应变率为1s-1时微孔的形成为流动软化的主要机制。

Abstract:

Hot deformation behavior of TiH₂-based PM near α titanium alloy Ti-1100 alloys has been investigated at temperature range of 973–1173K and strain rate range of 0.01–1.0s^_-1 by hot compression tests. The Arrhenius constitutive equation was developed and the hot deformation activation energy was calculated to be 334.76 kJ/mol. The temperature sensitivities (θ) were calculated by a modified function and the strain rate sensitivities (m) were determined. Based on the results of temperature sensitivity and strain rate sensitivity together with microstucture at strain rate of 0.5, the hot working condition was analyzed. It was found that the instability regions is mostly appeared at strain rate of 0.01s^_-1 and 1s^_-1 over whole temperature range, while the optimal hot working conditions are obtained in the range of 1135K 0.29s^_-1 to 1173K 0.76s^_-1, and 1040 0.33 s^_-1 to 1096K 0.6s^_-1. Besides, the microstucture analysis reveals that the dynamic recrystallization (DRX) occurs at strain rate of 0.01–0.1s^_-1, while the formation of micro-voids is the dominant mechanism of flow softening at strain rate of 1s^_-1.