Abstract High-resolution crystal plasticity-finite element method (CPFEM) simulations are performed to provide new reference values of the Taylor factor M and the isotropic yield surface exponent a for high stacking fault energy face-centred-cubic (FCC) polycrystalline metals with random orientations. The visco-plastic Taylor factor with strain rate sensitivity M ˜ is introduced and linearly extrapolated to its zero strain rate sensitivity limit to give the new reference value of M. The linear extrapolation technique is also employed to define the new reference value of a . The obtained new reference values are 2.7 and 6.9, for M and a , respectively, which are much smaller than the reference values currently used for FCC materials based on full constraint (FC) Taylor model calculations, i.e. 3.07 for M and 8 for a. Other state-of-the-art Taylor-type models, e.g. ALamel, ALamel with the type III relaxation (ALamel-T3) and the visco-plastic self-consistent (VPSC) models, can also give values for M and a much smaller than the FC-Taylor calculations. The performance of the CPFEM and these state-of-art Taylor-type models in terms of resolving deformation and stress fields within the aggregate can only be assessed in a statistical manner since all are statistical aggregate models. Selected statistical distributions are analysed for all models, by means of local deviations of the velocity gradient tensor, of the plastic deformation-rate tensor and of the stress tensor etc., for uniaxial tensile deformation. The ALamel models are found to provide similar statistics as CPFEM, whereas the VPSC model results are qualitatively different. The intra-grain analysis for CPFEM demonstrates that the intra-grain interactions are as much important as the local interactions at the grain boundaries.

中文翻译：

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FCC 金属的高级泰勒模型、泰勒因子和屈服面指数的评估

摘要 高分辨率晶体塑性有限元法 (CPFEM) 模拟为泰勒因子 M 和各向同性屈服面指数 a 提供新的参考值，用于高堆垛层错能面心立方 (FCC) 多晶金属的随机分布。方向。引入具有应变率敏感性 M 的粘塑性泰勒因子并线性外推到其零应变率敏感性极限，以给出 M 的新参考值。线性外推技术也用于定义 a 的新参考值。获得的新参考值分别为 M 和 a 的 2.7 和 6.9，远小于目前基于全约束（FC）泰勒模型计算的 FCC 材料的参考值，即 M 为 3.07，a 为 8。其他最先进的泰勒型模型，例如 ALamel、具有 III 型松弛 (ALamel-T3) 和粘塑性自洽 (VPSC) 模型的 ALamel 也可以给出 M 的值和更小的值比 FC-Taylor 计算。CPFEM 和这些最先进的泰勒型模型在解决骨料变形和应力场方面的性能只能以统计方式进行评估，因为它们都是统计骨料模型。对于单轴拉伸变形，通过速度梯度张量、塑性变形率张量和应力张量等的局部偏差，为所有模型分析选定的统计分布。发现 ALamel 模型提供与 CPFEM 相似的统计数据，而 VPSC 模型结果在性质上有所不同。