氢化钛粉末冶金制备的近α型Ti-1100合金的高温压缩性能

High temperature compression properties of nearαtype Ti-1100 alloy prepared by titanium hydride based powder metallurgy

以氢化钛粉为原料,采用粉末冶金法-热等静压法制备高温钛合金Ti-1100,并进行了等温压缩试验,通过压缩样品应力应变曲线进行压缩变形行为分析,再结合Arrhenius双曲正弦本构模型建立热压缩本构方程。通过应力应变曲线分析,发现应变速率在0.01 s^(−1)时,所有样品在加工硬化后均表现出稳态流变行为;而应变速率为1 s^(−1)、温度在900℃或1000℃时,流变应力随着变形达到稳态流变状态后,呈增加趋势。应变速率为0.01、0.1、1 s^(−1)时的热压缩变形激活能分别为96、165、232 kJ/mol。硬度测试结果表明显微硬度随温度和应变速率增加稍有降低趋势,当温度为950℃,应变速率为0.1 s^(−1)时,合金的硬度普遍较小,热加工性能最佳。

The isothermal compression experiments were carried out on high temperature titanium alloy Ti-1100 prepared by powder metallurgy using titanium hydride powder as raw material.The compression deformation behavior was analyzed through the obtained stress-strain curve of compressed samples,and then the thermal compression constitutive equation was established by using Arrhenius hyperbolic sinusoidal constitutive model.Through the analysis of the stress-strain curve,it is found out that when the strain rate is 0.01 s^(−1),all samples show steady-state rheological behavior.When the strain rate is 1 s^(−1) and the temperature is 900℃or 1000℃,the flow stress increases with deformation after steady-state rheological state.The activation energy of thermal compression deformation for strain rate at 0.01,0.1 s^(−1) and 1 s^(−1) are 96,165 kJ/mol and 232 kJ/mol,respectively.The hardness test results show that microhardness decreases slightly with increase of temperature and strain rate.When the temperature is 950℃and the strain rate is 0.1 s^(−1),the hardness of the alloy is generally small and the best hot workability can be achieved.