Al纳米线不同晶向力学行为和变形机制的模拟

采用分子动力学模拟计算方法，考察具有较高层错能的Al纳米线沿不同晶向的力学行为和变形机制。在相同计算条件下与具有较低层错能的Ni、Cu、Au和Ag等FCC金属纳米线进行比较。结果表明：在力学行为方面，Al纳米线的弹性模量呈现明显的结构各向异性，满足E_111] > E_110] > E_100]的关系，这一关系在FCC金属纳米线中普遍成立；Al纳米线的屈服应力随晶向呈现σ_y100] > σ_y111] > σ_y110]的关系，这一关系在具有较低层错能的FCC金属纳米线中不具有普遍性，这与体系中位错形成机制密切相关。根据拉伸变形过程微观结构的演变规律，阐明Al纳米线不同晶向的变形机制，并与具有较低层错能的Ni、Cu、Au和Ag等FCC金属纳米线的变形机制进行比较。结果表明，对于尺度较小的高层错能Al纳米线，Schmid因子和广义层错能均难以准确预测其变形机制。

Simulation of Mechanical Behavior and Deformation Mechanism of Al Nanowires Along Different Crystal Orientations

Mechanical behavior and deformation mechanism of Al nanowire along different crystal orientations are investigated with molecular dynamics simulation. They are compared with those of FCC metal nanowires with lower fault energy such as Ni, Cu, Au and Ag under same computational conditions. It is found that the elastic module of Al nanowire along different crystal orientations displays a relationship of E_111] > E_110] > E_100], which is generally true in FCC nanowires. The yield stress of Al nanowire along different crystal orientations displays a relationship of σ_y100] > σ_y111] > σ_y110], which is not generally true in FCC nanowires. Furthermore, deformation mechanism of Al nanowire along crystal orientations is clarified according to the evolution of microstructures. It is compared with that of nanowires of Ni, Cu, Au and Ag. It was found that it is difficult to predict deformation mechanism accurately with Schmid factor and stacking fault energy for Al nanowire with high fault energy in small scales.