Thermomechanical processing of titanium alloys often requires complex routes to achieve the desired final microstructure. Recent advances in modeling and simulation tools have facilitated the optimization of these processing routes. However, existing models often fail to accurately predict microstructural changes at large deformations. In this study, we refine the physical principles of an existing mean-field model and propose a calibration method that uses experimental results under isothermal conditions, accounting for the actual local deformation within the workpiece. This new approach improves the predictability of microstructural changes due to continuous dynamic recrystallization during torsion and compression experiments. Additionally, we integrate the model into the commercial FEM-based DEFORM™ 2D software to predict the local microstructure evolution within hot torsion specimens thermomechanically treated by resistive heating. Validation using non-isothermal deformation tests demonstrates that the model provides realistic simulations at high strain rates, where adiabatic heat modifies temperature, flow stress and microstructure. This study demonstrates the intrinsic correlation between microstructure, flow behavior, and workpiece geometry, considering the impact of deformation history in thermomechanical processes.

中文翻译：

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连续动态重结晶的预测介观模型


钛合金的热机械加工通常需要复杂的路线才能获得所需的最终微观结构。建模和仿真工具的最新进展促进了这些加工路线的优化。然而，现有模型通常无法准确预测大变形时的微观结构变化。在这项研究中，我们改进了现有平均场模型的物理原理，并提出了一种校准方法，该方法使用等温条件下的实验结果，考虑工件内的实际局部变形。这种新方法提高了扭转和压缩实验期间由于连续动态再结晶而导致的微观结构变化的可预测性。此外，我们将该模型集成到基于 FEM 的商用 DEFORM™ 2D 软件中，以预测通过电阻加热进行热机械处理的热扭转样品中的局部微观结构演变。使用非等温变形测试的验证表明，该模型提供了高应变率下的真实模拟，其中绝热热改变了温度、流动应力和微观结构。这项研究证明了微观结构、流动行为和工件几何形状之间的内在相关性，考虑到热机械过程中变形历史的影响。