Meng Xiankai, Zhou Jianzhong, Huang Shu, Su Chun, Sheng Jie
School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China.
School of Mechanical & Vehicle Engineering, Changzhou Institute of Technology, Changzhou 213022, China.
Materials (Basel). 2017 Jan 18;10(1):73. doi: 10.3390/ma10010073.
The laser shock wave (LSW) generated by the interaction between a laser and a material has been widely used in laser manufacturing, such as laser shock peening and laser shock forming. However, due to the high strain rate, the propagation of LSW in materials, especially LSW at elevated temperatures, is difficult to study through experimental methods. A molecular dynamics simulation was used in this study to investigate the propagation of LSW in an Al-Cu alloy. The Hugoniot relations of LSW were obtained at different temperatures and the effects of elevated temperatures on shock velocity and shock pressure were analyzed. Then the elastic and plastic wave of the LSW was researched. Finally, the evolution of dislocations induced by LSW and its mechanism under elevated temperatures was explored. The results indicate that the shock velocity and shock pressure induced by LSW both decrease with the increasing temperatures. Moreover, the velocity of elastic wave and plastic wave both decrease with the increasing treatment temperature, while their difference decreases as the temperature increases. Moreover, the dislocation atoms increases with the increasing temperatures before 2 ps, while it decreases with the increasing temperatures after 2 ps. The reason for the results is related to the formation and evolution of extended dislocations.
激光与材料相互作用产生的激光冲击波（LSW）已广泛应用于激光制造领域，如激光冲击喷丸和激光冲击成形。然而，由于应变速率高，LSW在材料中的传播，尤其是高温下的LSW传播，很难通过实验方法进行研究。本研究采用分子动力学模拟来研究LSW在铝铜合金中的传播。获得了不同温度下LSW的雨贡纽关系，并分析了高温对冲击速度和冲击压力的影响。然后研究了LSW的弹性波和塑性波。最后，探讨了高温下LSW诱发的位错演化及其机制。结果表明，LSW诱发的冲击速度和冲击压力均随温度升高而降低。此外，弹性波和塑性波的速度均随处理温度的升高而降低，而它们之间的差值随温度升高而减小。此外，位错原子在2 ps之前随温度升高而增加，而在2 ps之后随温度升高而减少。这些结果的原因与扩展位错的形成和演化有关。
