Abstract Micro-scale thermal interface grooving (TIG), as an important breakdown mechanism of single lamella and the key to spheroidization of lamellar colony, does significant influence on the mechanical response and microstructural evolution of titanium alloy with lamellar colony during hot working. This influence may become remarkable by coupling with meso-scale deformation anisotropy of the colony. The coupled effect across different scales is crucial to the spheroidization of lamellar colony, while rare related research is reported due to the difficulty in experiment. In this work, a multi-scale MCCPFEM framework was proposed to model on the micro-scale TIG and meso-scale deformation anisotropy through the fully coupling of lattice kinetic Monte Carlo (MC) model and crystal plasticity finite element model (CPFEM). During the modeling, the modified MC algorithm was established based on the multiple-integral method (MIM) solution with Mullin's theory, which accounts for the TIG's microstructural evolution. In addition, the deformation anisotropy at different length scales including strain localization at lamella, and strain partitioning at colony was characterized by an explicit CPFEM which includes resistance anisotropy of slip systems, evolution of dislocations and high-fidelity representative lamellar colony. At the same time, geometrically necessary dislocation (GND) was also considered in the CPFEM by developing a new algorithm with mesh-free methodology and re-construct radial basic shape functions. The fully coupling of the multi-scale MCCPFEM was realized through the microstructure-based 2D grids acting as both finite elements and lattice sites. Moreover, re-set ‘zero’ of the deformation gradient of the TIG mesh was proposed to characterize the strain-free state of new TIG nucleation. Then, the TIG-induced changes in the dislocation density, lattice rotation, strain-free state and morphological characteristics were returned to MCCPFEM to determine the heterogeneous deformation and anisotropic mechanical response of the lamellar colony. With this multi-scale model, the coupled effect of the deformation anisotropy (strain localization in beta phase, stress relief in TIG and local internal stress concentration in alpha lamella) and TIG-induced microstructural evolution during the isothermal compression of the IMI834 alloy with lamellar colony is well captured and analyzed.

中文翻译：

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多尺度 MCCPFEM 框架：模拟层状菌落钛合金的热界面开槽和变形各向异性

摘要 微尺度热界面开槽(TIG)作为单层的重要击穿机制和层状菌落球化的关键，对热加工过程中带层状菌落的钛合金的力学响应和显微组织演化具有重要影响。通过与群体的中尺度变形各向异性耦合，这种影响可能变得显着。不同尺度的耦合效应对层状菌落的球化至关重要，而由于实验难度大，相关研究鲜见报道。在这项工作中，提出了一种多尺度 MCCPFEM 框架，通过晶格动力学蒙特卡罗 (MC) 模型和晶体塑性有限元模型 (CPFEM) 的完全耦合，对微尺度 TIG 和中尺度变形各向异性进行建模。在建模过程中，改进的 MC 算法是基于多积分法 (MIM) 解决方案和 Mullin 理论建立的，它解释了 TIG 的微观结构演变。此外，不同长度尺度的变形各向异性，包括片层的应变局部化和菌落的应变分配，由显式 CPFEM 表征，其中包括滑移系统的阻力各向异性、位错演化和高保真代表性层状菌落。同时，在 CPFEM 中还考虑了几何必要位错 (GND)，开发了一种新算法，采用无网格方法并重新构建径向基本形状函数。多尺度 MCCPFEM 的完全耦合是通过作为有限元和晶格点的基于微结构的 2D 网格实现的。而且，建议将 TIG 网格的变形梯度重新设置为“零”，以表征新 TIG 成核的无应变状态。然后，将 TIG 引起的位错密度、晶格旋转、无应变状态和形态特征的变化返回到 MCCPFEM，以确定层状菌落的异质变形和各向异性机械响应。使用这个多尺度模型，在 IMI834 合金的等温压缩过程中，变形各向异性（β 相的应变局部化、TIG 中的应力消除和 α 片层中的局部内部应力集中）和 TIG 诱导的微观结构演变的耦合效应菌落被很好地捕获和分析。将 TIG 引起的位错密度、晶格旋转、无应变状态和形态特征的变化返回到 MCCPFEM，以确定层状菌落的异质变形和各向异性机械响应。使用这个多尺度模型，在 IMI834 合金的等温压缩过程中，变形各向异性（β 相的应变局部化、TIG 中的应力消除和 α 片层中的局部内部应力集中）和 TIG 诱导的微观结构演变的耦合效应菌落被很好地捕获和分析。将 TIG 引起的位错密度、晶格旋转、无应变状态和形态特征的变化返回到 MCCPFEM，以确定层状菌落的异质变形和各向异性机械响应。使用这个多尺度模型，在 IMI834 合金的等温压缩过程中，变形各向异性（β 相的应变局部化、TIG 中的应力消除和 α 片层中的局部内部应力集中）和 TIG 诱导的微观结构演变的耦合效应菌落被很好地捕获和分析。