FCC铝纳米压痕的多尺度模拟

Multiscale Simulations of FCC Al Nanoindentation

采用准连续介质方法模拟面心立方(FCC)铝单晶薄膜在纳米压痕下产生的变形过程。分别用四种不同的压头宽度,得出载荷-位移响应曲线和应变能变化曲线,发现压头宽度越大,晶体产生塑性变形的临界载荷越大;临界载荷的大小和采用能量理论预测的大小基本一致;模拟过程中,观察到位错成核现象,了解到载荷-位移响应曲线的突降是由位错成核现象所引起,四种情况中压头载荷的降幅大致相同;最后分析了模型在原子层次下的变形机理。

The quasi-continuum method was used to simulate the processes of early stages deformation in FCC Al nanoindentation. Four different widths of indenters were used, and the schematic variations of applied force and the strain energy versus the displacement of indenter were obtained in the specimens. The results show that when the width of indenters increases, the critical load of incipient plastic in crystals increases. The simulated values of critical load are in good agreement with theoretical values. The dislocation dipole nucleation event was observed in the simulation. It＇s shown that the sharp decrease in the loaddisplacement response curve is due to the nucleation of dislocations. At last, the atomic deformation mechanisms in crystals were discussed.