Abstract In this study, strain rate effects on the tensile and compressive properties of nano-crystalline nanoporous gold (nc-NPAu) are investigated by performing molecular dynamics simulations. For this purpose, atomistic models of nc-NPAu structures with three different grain sizes are generated through a novel modeling technique based on the Voronoi tessellation method. Additionally, an adaptive common neighbor analysis (aCNA) is carried out to examine the evolution of the crystal structure. In this way, the deformation mechanisms of nc-NPAu atomistic models are thoroughly investigated. The findings point out that mechanical properties of nc-NPAu specimens such as toughness, ultimate and yield strengths grow at increasing strain rates for both tensile and compressive loadings while their elastic moduli exhibit less significant variations at different strain rates. Furthermore, the study also shows that in addition to dislocation motion, several other deformation mechanisms including grain rotation, grain boundary sliding and grain travelling are observed to be effective for nc-NPAu.

中文翻译：

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应变率对纳米晶纳米多孔金拉伸和压缩行为的影响：分子动力学研究

摘要 本研究通过分子动力学模拟研究了应变速率对纳米晶纳米多孔金 (nc-NPAu) 拉伸和压缩性能的影响。为此，通过基于 Voronoi 镶嵌方法的新型建模技术生成了具有三种不同晶粒尺寸的 nc-NPAu 结构的原子模型。此外，还进行了自适应公共邻域分析 (aCNA) 以检查晶体结构的演变。通过这种方式，对 nc-NPAu 原子模型的变形机制进行了彻底的研究。研究结果指出，nc-NPAu 试样的机械性能，如韧性、对于拉伸和压缩载荷，极限强度和屈服强度随着应变速率的增加而增加，而它们的弹性模量在不同的应变速率下表现出的变化不大。此外，研究还表明，除了位错运动外，还观察到其他几种变形机制，包括晶粒旋转、晶界滑动和晶粒移动，对 nc-NPAu 也是有效的。