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针对预拉伸和预扭转变形后的拉扭组合实验,用多晶集合体模型为代表性单元,结合晶体塑性理论对多晶Cu进行了晶粒尺度的屈服特性研究,采用子模型法对晶粒尺度的代表性单元模型和多晶Cu试样拉扭实验进行跨尺度材料力学行为分析.结合对多晶集合体的后继屈服面形状及演化趋势的研究,探讨不同加载路径和不同屈服点定义对材料后继屈服面的影响;通过对不同加载路径多晶Cu非均匀性的统计分析,探讨加载历史对多晶材料细观塑性变形不均匀性的影响.分析结果表明:后继屈服面的形状和尖角效应的出现与预加载方向和屈服定义有关;加载路径不同,多晶体内变形不均匀性的差异很大.运用子模型的晶体塑性模拟与后继屈服实验的结果有较好的一致性.
Aiming at the combination of tensile and torsion tests after pre-stretch and pre-twist deformation, the polycrystalline aggregate model is taken as the representative unit, and the crystal plasticity theory is used to study the yield behavior of polycrystalline Cu at grain size. Particle size representative unit model and polycrystalline Cu sample pull-torsion test to conduct cross-sectional mechanical behavior analysis.Combined with polycrystalline aggregates subsequent yield surface shape and evolution trend to explore different loading paths and different yield point definition The influence of loading history on the inhomogeneous plastic deformation of polycrystalline materials was investigated by statistical analysis of the heterogeneity of polycrystalline Cu in different loading paths.The analysis results show that the shape of the subsequent yield surface The appearance of the sharp corner effect is related to the pre-loading direction and the yield definition. The different loading paths lead to great differences in the inhomogeneity of the polycrystal deformation. The crystal plasticity simulation using the sub-model is in good agreement with the results of the subsequent yielding test.