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

通过热压缩试验,研究了TiH2基粉末冶金近α钛合金Ti-1100在973~1173 K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334.76kJ/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0.01和1s^-1时,在整个温度范围内出现了失稳区,而在1135 K/0.29s^-1至1173 K/0.76s^-1、1040 K/0.33s^-1至1096 K/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时微孔的形成是流动软化的主要机制。

Hot deformation behavior of TiH2-based powder metallurgy(PM)near-αtitanium alloy Ti-1100 alloys was investigated in temperature range of 973~1173 K 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 sensitivity(θ)was calculated by a modified function and the strain rate sensitivity(m)was determined.Based on the results of temperature sensitivity and strain rate sensitivity together with microstructure at strain of 0.5,the hot working condition was analyzed.Results show that the instability regions mainly appear at strain rate of 0.01 and 1s^-1 over whole temperature range,while the optimal hot working conditions are obtained in the range of 1135 K/0.29s^-1 to 1173 K/0.76s^-1,and 1040 K/0.33s^-1 to 1096 K/0.6s^-1.Besides,the dynamic recrystallization(DRX)occurs at strain rate of 0.01~0.1s^-1,and the formation of micro-voids is the dominant mechanism of flow softening at strain rate of 1s^-1.