Abstract Flow softening of Ti-17 alloy with the lamellar structure during hot deformation is investigated in this work. For this purpose, hot compression tests are conducted with strain rate of 0.001–10 s−1 at 780–860 °C. The experimental results are analyzed through theoretical calculation and microstructure observation (SEM, TEM and EBSD). Flow softening extent of Ti-17 alloy increases with the decreasing temperature and increasing strain rate. The softening behavior can be explained by the two aspects: deformation heating and microstructure changes. Deformation heating effect is caused by temperature rise, which is more serious at higher strain rate. Microstructure changes include the bending, kinking, rotation and separation of the lamellar alpha, which can be defined as the pan-globularization of alpha phase. In addition, the EBSD observations indicate that the continuous dynamic recrystallization occurs in beta phase. Microstructure changes of alpha and beta phases influence together flow softening behavior. Specifically, the pan-globularization of alpha phase and continuous dynamic recrystallization of beta phase result in flow softening of Ti-17 alloy.

中文翻译：

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层状组织Ti-17合金热变形流动软化分析

摘要 本文研究了层状结构Ti-17合金在热变形过程中的流动软化。为此，在 780–860 °C 下以 0.001–10 s-1 的应变速率进行热压缩试验。通过理论计算和微观结构观察（SEM、TEM和EBSD）对实验结果进行分析。Ti-17合金的流动软化程度随着温度的降低和应变速率的增加而增加。软化行为可以从两个方面来解释：变形加热和微观结构变化。变形热效应是由温度升高引起的，应变率越高，变形热效应越严重。微观结构变化包括层状α的弯曲、扭结、旋转和分离，可定义为α相的泛球化。此外，EBSD 观察表明连续动态再结晶发生在 β 相。α 相和β 相的微观结构变化共同影响流动软化行为。具体而言，α相的泛球化和β相的连续动态再结晶导致Ti-17合金的流动软化。