A crystal-plasticity cyclic constitutive model of polycrystalline material considering intra-granular heterogeneous dislocation substructures, in terms of three dislocation categories: mobile dislocations, immobile dislocations in the cell interiors and in the cell walls, is proposed based on the existing microscopic and macroscopic experimental results. The multiplication, annihilation, rearrangement and immobilization of dislocations on each slip system are taken as the basic evolutionary mechanism of the three dislocation categories, and the cross-slip of screw dislocations is viewed as the dynamic recovery mechanism at room temperature. The slip resistance associated with the isotropic hardening rule results from the interactions of dislocations on the slip systems. Meanwhile, a modified nonlinear kinematic hardening rule and a rate-dependent flow rule at the slip system level are employed to improve the predictive capability of the model for ratchetting deformation. The predictive ability of the developed model to uniaxial and multiaxial ratchetting in macroscopic scale is verified by comparing with the experimental results of polycrystalline 316L stainless steel. The ratchetting in intra-granular scale which is obviously dependent on the crystallographic orientation and stress levels can be reasonably predicted by the proposed model.

中文翻译：

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考虑位错子结构的多晶材料棘轮的晶体-塑性循环本构模型

基于现有的微观和宏观实验，提出了考虑晶内异质位错亚结构的多晶材料的晶体塑性循环本构模型，该结构考虑了三种位错类别：移动位错，细胞内部和细胞壁中的固定位错。结果。每个滑移系统中位错的增殖，an灭，重排和固定化是这三种位错类别的基本演化机理，而螺钉位错的交叉滑动被视为室温下的动态恢复机制。与各向同性硬化规则相关的滑动阻力是由滑动系统上位错的相互作用引起的。与此同时，在滑移系统水平上采用了改进的非线性运动硬化规则和速率相关的流动规则，以提高模型对棘轮形变形的预测能力。通过与多晶316L不锈钢的实验结果进行比较，验证了所开发模型对宏观单轴和多轴棘轮运动的预测能力。所提出的模型可以合理地预测晶粒内的rat裂，这显然取决于晶体的取向和应力水平。通过与多晶316L不锈钢的实验结果进行比较，验证了所开发模型对宏观单轴和多轴棘轮运动的预测能力。所提出的模型可以合理地预测晶粒内的rat裂，这显然取决于晶体的取向和应力水平。通过与多晶316L不锈钢的实验结果进行比较，验证了所开发模型对宏观单轴和多轴棘轮运动的预测能力。所提出的模型可以合理地预测晶粒内的rat裂，这显然取决于晶体的取向和应力水平。