采用结合双温模型的分子动力学方法详尽描述了应力约束区域内部金属薄膜后向层裂的动力学过程.与辐照表面在激光加热作用下机械稳定性受到强烈影响而发生的前向喷射不同,后向层裂是冷材料的断裂.分析了层裂机制,得出靶材是在卸载波及被反射的压力波的共同作用下发生层裂;探讨了激光诱导压力波的传播规律,预测了不同靶厚下的层裂厚度及其对层裂开始时间的影响.

Using molecular dynamics methods combined with two-step radiation heating model, a complete microscopic description of the dynamic progresses involved in laser induced back-surface spallation in metallic film in stress confinement regime is provided. Different from the front-surface ejection with strongly affected mechanical stability of the front-surface by laser heating, the back-surface spallation is a disintegration of cold material. The mechanism of spallation is analyzed as a result of the interaction of the unloading wave and reflected stress wave. The propagation of laser-induced stress wave is also further investigated, and the influences of film thickness on spall thickness as well as the time when spallation begins are predicted.