Abstract We generated a three-dimensional stress map of grains and grain boundaries in uniaxial strained Nb3Sn composite, using a scale-coupled model generated by the polycrystalline finite element method and based on the linear elastic theory of closely packed fiber-reinforced composites. The model takes into account the transfer of stress from a Cu-Sn matrix to a single Nb3Sn filament composed of inner elongated and outer equiaxed grains. Due to differences in grain morphology and orientation, stress inhomogeneity arises first in the filament. The interconnected grain boundary networks in Nb3Sn constrain grain deformation by fostering stress concentration at intersections between multiple grains. The degree of stress concentration can be as high as 2.08. Our model simulations show a random distribution of grain boundary orientations within stress concentration zones and provide detailed information on how and where stress inhomogeneity is likely to produce crack initiation in Nb3Sn.

中文翻译：

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单轴应变 Nb3Sn 中的晶界变形

摘要 我们使用由多晶有限元方法生成的尺度耦合模型并基于紧密堆积的纤维增强复合材料的线弹性理论，生成了单轴应变 Nb3Sn 复合材料中晶粒和晶界的三维应力图。该模型考虑了应力从 Cu-Sn 基体到由内部细长晶粒和外部等轴晶粒组成的单个 Nb3Sn 细丝的转移。由于晶粒形态和取向的差异，应力不均匀首先出现在细丝中。Nb3Sn 中相互连接的晶界网络通过在多个晶粒之间的交叉处促进应力集中来限制晶粒变形。应力集中度可高达2.08。