Abstract We investigated the effect of texture-induced plastic anisotropy on the deformation behavior of ultrafine-grained aluminum films with a bicrystalline texture (two grain variants). The films were uniaxially loaded along two different directions such that the heterogeneity in the plastic behavior of the two grain variants due to plastic anisotropy was minimized along one direction and maximized along the other. The bicrystalline films show smaller strain rate sensitivity and hysteresis of stress-strain response when they are deformed along the direction that minimizes plastic heterogeneity compared to the direction that maximizes it. Notable differences in flow stress and residual hardening were also found for the two loading directions. To quantitatively understand the effect of plastic anisotropy, we simulated the response of the films using three-dimensional finite elements with a microstructurally explicit model built from TEM automated crystal orientation mapping of the samples that includes a grain boundary region, along with crystal plasticity and anisotropic elasticity. The simulations reveal markedly different distribution of stresses and strains in the two grain variants when loading is performed along the two directions, which can be directly related to the ratio of Schmid factors of their most active slip systems.

中文翻译：

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塑性各向异性对双晶铝薄膜变形行为的影响——实验和建模

摘要 我们研究了织构诱导的塑性各向异性对具有双晶织构（两种晶粒变体）的超细晶粒铝膜变形行为的影响。薄膜沿两个不同的方向单轴加载，使得由于塑性各向异性导致的两种晶粒变体的塑性行为的不均匀性沿一个方向最小化，沿另一个方向最大化。当双晶薄膜沿着最小化塑性异质性的方向变形时，双晶薄膜表现出较小的应变率敏感性和应力-应变响应滞后，与最大化塑性异质性的方向相比。在两个加载方向上也发现了流动应力和残余硬化的显着差异。为了定量理解塑性各向异性的影响，我们使用三维有限元模拟了薄膜的响应，该模型通过样品的 TEM 自动晶体取向映射构建的显微结构模型，包括晶界区域，以及晶体塑性和各向异性弹性。模拟结果显示，当沿两个方向加载时，两种晶粒变体中的应力和应变分布明显不同，这可能与其最活跃的滑移系统的 Schmid 因子比直接相关。