Abstract The plastic deformation at high temperatures of two-phase titanium alloys is modelled using a mesoscale approach to describe the complex interactions between different populations of dislocation densities. The static and dynamic recovery, as well as of continuous dynamic recrystallization, is modelled. The flow stresses of both α and β phases are calculated using constitutive equations combined with a load partitioning model between the α and β phases. The dislocation populations are separated into three categories, named mobile, immobile and walls, and separated rate equations are developed for each reaction between them. Several microstructure features are calculated, such as mean subgrain size, grain size, dislocation densities and boundary misorientation. Additionally, glide velocity is also estimated. Hot compression experiments of a Ti-5553 alloy at temperatures between 1073 K and 1193 K and strain rates between 0.001 s−1 and 10 s−1 are used for validation. The flow softening observed in the α+β domain is attributed to the change in load partitioning. Moreover, the decrease in grain and subgrain size with the increase in strain rate and decrease in temperature is well predicted by the proposed model as well as the evolution of a fully static recrystallized microstructure into a continuous dynamic recrystallized one.

中文翻译：

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基于位错的 Ti5553 合金微观结构演变和流动应力模型

摘要 使用中尺度方法对两相钛合金在高温下的塑性变形进行建模，以描述不同位错密度群之间的复杂相互作用。对静态和动态恢复以及连续动态再结晶进行建模。α 和 β 相的流动应力是使用本构方程结合 α 和 β 相之间的载荷分配模型来计算的。位错群被分为三类，称为移动、固定和壁，并为它们之间的每个反应开发了分离速率方程。计算了几个微观结构特征，例如平均亚晶粒尺寸、晶粒尺寸、位错密度和边界错误。此外，还估计了滑行速度。Ti-5553 合金在 1073 K 和 1193 K 之间的温度和 0.001 s-1 和 10 s-1 之间的应变速率下的热压缩实验用于验证。在 α+β 域中观察到的流动软化归因于载荷分配的变化。此外，所提出的模型可以很好地预测晶粒和亚晶粒尺寸随着应变速率的增加和温度的降低而减小，以及完全静态再结晶微观结构向连续动态再结晶微观结构的演变。