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利用Gleeble-3800热模拟试验机,在温度800～980℃及应变速率0.001～1 s-1范围内进行了TA15钛合金热压缩试验,研究了TA15钛合金在热变形过程中力学行为特点及微观组织演变规律.研究结果显示,变形温度和应变速率对流变应力影响显著.随着变形温度升高和应变速率的降低,最大变形抗力减小,且使得流变曲线在较小应变下即达到稳态.当变形温度低于或等于900℃时,随应变的增加合金的动态软化效应显著,当温度高于900℃时,合金的软化效应逐渐减弱,这主要与温度升高导致密排六方α相与体心立方β相两相比例改变进而导致主导软化机制改变有关.基于流变曲线,建立了考虑摩擦效应和应变补偿的热变形本构方程.对比分析表明所建立的双曲正弦型本构模型可较好地预测不同变形阶段合金流变应力,可为TA15钛合金热加工工艺的选择等提供参考依据.“,”Hot compression of TA15 titanium alloy was carried out by using Gleeble-3800 thermal simulator at the strain rate of 0.001-1 s-1 and the temperature of 800-980 ℃.The characteristics of mechanical behavior and microstructure evolution of TA15 alloy during hot deformation were studied.Results show that the flow stress is sensitive to deformation temperature and strain rate.With the decrease of strain rate and the increase of deformation temperature,the peak stress decreases,and the flow curve reaches the steady state at a small strain.When the deformation temperature is lower than or equal to 900 ℃,the dynamic softening effect gets more and more significant with the strain increasing,and the softening effect decreases with the increase of temperature.This is mainly related to the change on the fraction of α phase (or/and β phase) which can cause the change of the dominant softening mechanism.Based on the flow curves,the constitutive equation of hot deformation considering the effect of friction and strain compensation was established.The comparative results between experimental flow stress and calculated values show that the obtained hyperbolic sine constitutive equation can well predict flow stress at different deformation stages.These results are beneficial to developing a better hot working process and also to choosing the equipment.