Nanoindentation process is performed by molecular dynamics simulations to investigate the plastic deformation phenomena and mechanical properties of the polycrystalline tantalum (Ta) substrate. The comparison of mechanical behaviors between the single crystal and polycrystalline Ta is analyzed. The effects of grain size, indenter radius, indentation velocity, and temperature are deeply investigated. Further, the important factors of mechanical property such as the plastic deformation, dislocation, amorphization process, indentation force, yield pressure, and von Mises stress are evaluated. The results show that the phase transformations and dislocations almost absent in the grains. Instead, the dislocations densely occur in the grain boundaries, the amorphization regions are formed around the indentation areas and develop along the grain boundaries. The high von Mises stresses are mainly distributed around the indentation areas and in the grain boundaries. The single crystal tantalum shows better mechanical characteristics than the polycrystalline tantalum such as harder to deform, higher yield pressure, and lower dislocation.

通过分子动力学模拟执行纳米压痕工艺，以研究多晶钽（Ta）衬底的塑性变形现象和机械性能。分析了单晶Ta和多晶Ta的力学行为的比较。深入研究了晶粒尺寸，压头半径，压痕速度和温度的影响。此外，评估了机械性能的重要因素，例如塑性变形，位错，非晶化过程，压入力，屈服压力和冯·米塞斯应力。结果表明，晶粒中几乎没有相变和位错。相反，位错密集地发生在晶界，非晶区形成在压痕区周围并沿晶界发展。von Mises高应力主要分布在压痕区周围和晶界中。与多晶钽相比，单晶钽显示出更好的机械特性，例如更难变形，更高的屈服压力和更低的位错。