Atomic simulations of influence of twinning on crack propagation of Al

作者：An MinRong^*; Song HaiYang

来源：Science China Physics,Mechanics & Astronomy, 2013, 56(10): 1938-1944.

DOI：10.1007/s11433-013-5228-9

• twin boundary
• crack orientation
• dislocation
• molecular dynamic simulation

Molecular dynamics simulation was performed to investigate the influence of twin boundary (TB) spacing on crack propagation of Al. This study reveals the orientation of initial crack may affect the mechanism of crack growth obviously. TB strengthens Al when the crack orientation is parallel with TB because of the hinderance of TB to the emission of the dislocations. The results indicate that there is an optimal TB spacing for mechanical properties of the Al, exhibiting reverse HP (Hall-Petch) and HP effect when the TB spacing is near the critical TB spacing. Furthermore, we find that there is a yield strength hardening effect in nanotwinned Al when the crack orientation is perpendicular to the TB, and the Young's modulus is smaller in the nanotwinned Al than that of twin free Al. The studies also demonstrate that this distinctive deformation behavior is related to nucleation of dislocations and the repulsive force of TB to the dislocations and crack propagation, as well as the distance between the crack tip and the TB.

• 出版日期2013-10
• 单位西安邮电大学