The effect of pore size on the deformation mechanism and mechanical properties of nanoporous Ni under tension and compression tests is studied using molecular dynamic simulations in terms of atomic trajectories, dislocation extraction algorithm, and the stress–strain curve. The simulation results show that samples have a longer elastic deformation period during tension compared to that during compression. Dislocations nucleate at pore surfaces and propagate until they are terminated by neighboring pores. Samples under tension have lower ultimate stress and higher strain at ultimate stress compared to those of samples under compression. Samples with smaller pore diameter have more transformation from face-centered cubic to hexagonal close-packed structures due to more dislocation activity. The ultimate stress of samples significantly decreases with increasing pore diameter.

中文翻译：

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利用分子动力学模拟研究了纳米多孔镍的机械响应。

使用分子动力学模拟，原子轨迹，位错提取算法和应力-应变曲线研究了孔径对纳米多孔镍在拉伸和压缩试验下的变形机理和力学性能的影响。仿真结果表明，与压缩过程相比，样品在拉伸过程中具有更长的弹性变形周期。位错在孔表面成核并扩散，直到它们被相邻的孔终止。与处于压缩状态的样品相比，处于拉伸状态的样品具有较低的极限应力，并且在极限应力下具有较高的应变。由于位错活性更高，具有较小孔径的样品具有更多的从面心立方到六方密堆积结构的转变。