Grain boundary effect in nanoindentation of Gu biocrystal using molecular dynamic simulation
Grain boundary effect in nanoindentation of Gu biocrystal using molecular dynamic simulation
复制标题
利用分子动力学模拟研究 Gu 生物晶体纳米压痕中的晶界效应
DOI：
10.11522/pscjspe.2019a.0_56
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
B. Anthony
中科院分区：
文献类型：
--
作者：
Fang Duan;Zhu Wule;Ju Bing;B. Anthony
纳米压痕是一种在纳米尺度上分析材料力学响应的典型技术。然而，在纳米压痕过程中的晶界的影响仍然不清楚，需要广泛的研究，因为它们的机械和物理性能的显着影响。本文采用分子动力学（MD）模拟方法，研究了在不同的压痕速度和不同的晶界距离下，晶界对Cu生物晶体纳米压痕的影响。研究了晶界对生物晶体压入力、位错演化和硬度的影响。首先，随着压痕深度的增加，位错长度和密度增加。其次，压痕力下降现象检测从所获得的加载曲线。这些载荷下降是位错成核开始的结果，因此从纯弹性变形过渡到弹塑性变形。当位错到达晶界时，它将合并到晶界平面，直到压痕深度增加到一定程度。晶界处的最大应力值小于远离晶界处的最大应力值。最后，随着压痕速度的增加，MD模拟得到的应力、温度和位错都变大。
Nanoindentation is a typical technique for analysis of the mechanical responses of materials at nanometer scale. However, the effect of grain boundary during the nanoindentation process remains indistinct and need to be extensively researched because of their significant effects on the mechanical and physical properties. In this paper, molecular dynamics (MD) simulation was performed in order to investigate the grain boundary effect on nanoindentation of Cu biocrystal at different distances from grain boundary and different indentation speeds. The effect of grain boundary (GB) on indentation force, dislocation evolution, and hardness of Gu biocrystal was investigated. Firstly, as the indentation depth increases, the dislocation length and density increase. Secondly, indentation force drops phenomenon were detected from the obtained loading curves. These load drops are the result of the initiation of dislocation nucleation and so the transition from purely elastic to elastic-plastic deformation. When the dislocation reaches the GB, it will merge into the grain boundary plane until the indentation depth increase to some extent. The results also indicate that the maximum stress on the grain boundary is lower than its value far from the grain boundary. Finally, with the indentation speed increase, the stress, temperature and dislocation obtained from MD simulation became larger.