Abstract Dislocation dynamics simulation is used to investigate the effect of grain size and grain shape on the flow stress in model copper grains. We consider grains of 1.25–10 μm size, three orientations ( , and ) and three shapes (cube, plate and needles). Two types of periodic aggregates with one or four grains are simulated to investigate different dislocation flux at grain boundaries. It is shown that in all cases the flow stress varies linearly with the inverse of the square root of the grain size, with a proportionality factor varying strongly with the grain orientation and shape. Simulation results are discussed in the light of other simulation results and experimental observations. Finally, a simple model is proposed to account for the grain shape influence on the grain size effect.

中文翻译：

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晶粒尺寸和形状对流动应力的影响：位错动力学研究

摘要 利用位错动力学模拟研究了晶粒尺寸和晶粒形状对模型铜晶粒中流动应力的影响。我们考虑 1.25–10 μm 大小、三个方向（ 、 和 ）和三种形状（立方体、板状和针状）的晶粒。模拟了具有一粒或四粒的两种周期性聚集体，以研究晶界处的不同位错通量。结果表明，在所有情况下，流动应力随晶粒尺寸平方根的倒数线性变化，比例因子随晶粒取向和形状的变化而强烈变化。根据其他模拟结果和实验观察讨论模拟结果。最后，提出了一个简单的模型来解释晶粒形状对晶粒尺寸效应的影响。