本文以 Ti-575 钛合金为研究对象，分别对魏氏组织和双态组织 Ti-575 钛合金进行热模拟压缩实验，分析不同热变形条件下的真应力 - 应变曲线，构建了其在 α+β 相区的热变形本构方程，并分别探究了变形温度和应变速率对微观组织的影响。 结果表明，流变应力值随着变形温度的升高而降低，随着应变速率的升高而升高；当应变速率为0.1 s -1 及以上时，随着变形温度的升高流变曲线出现了不连续屈服现象。 根据两种组织 Ti-575 钛合金流变曲线的峰值应力，分别计算出其在 α+β 相区的变形激活能，构建 Arrhenius 型热变形本构方程。 在不同的热变形条件下，随着变形温度的升高，魏氏组织 Ti-575 钛合金动态再结晶的程度越来越大，而双态组织 Ti-575 钛合金等轴 α p 相体积分数和尺寸逐渐降低；随着应变速率的降低，魏氏组织 Ti-575 钛合金动态再结晶的程度逐渐增大，而双态组织 Ti-575 钛合金等轴 α p 相体积分数先减少后增加；双态组织 Ti-575 钛合金在 830 ℃ 或 1 s -1 应变速率下热压缩时，显微组织中残留少量的粗片层 α 相没有发生相变， β t 基体中会有硅化物析出。

Taking Ti-575 titanium alloy as the research object, the thermal mechanical compression experiments were conducted on both lamellar structure and bimodal structure Ti-575 titanium alloys. The true stress-strain curves under different thermal deformation conditions were analyzed, the constitutive equation for hot deformation in the α+β phase region was established, and the influence of the deformation temperature and strain rate on the microstructure was nvestigated. The results show that the flow stress decreases with increasing deformation temperature and increases with increasing strain rate. When the strain rate is 0.1 s -1 or higher, the flow curve exhibits discontinuous yielding with increasing deformation temperature. Based on the peak stress of the flow curves of the two types of Ti-575 titanium alloys, the deformation activation energy in the α+β phase region is calculated, and an Arrhenius-type constitutive equation for hot deformation is established. Under different thermal deformation conditions, with increasing deformation temperature, the degree of dynamic recrystallization in the lamellar structure Ti-575 titanium alloy increases, while the volume fraction and size of equiaxed α p phase in the bimodal structure Ti-575 titanium alloy gradually decrease. With decreasing strain rate, the degree of dynamic recrystallization in the lamellar structure Ti-575 titanium alloy gradually increases, while the volume fraction of equiaxed α p phase in the bimodal structure Ti-575 titanium alloy first decreases and then increases. When the bimodal structure Ti-575 titanium alloy is hot compressed at a temperature of 830 ℃ or a strain rate of 1 s -1 , a small amount of coarse lamellar α phase remains unchanged in the microstructure, and silicide precipitates in the β t matrix.