飞秒激光烧蚀CuZr非晶合金机理与烧蚀区结构分析

Mechanism of Femtosecond Laser Ablation of CuZr Amorphous Alloy and Microstructure of Ablation Zone's Matrix

采用结合双温模型的分子动力学的方法,数值模拟了脉宽100 fs,能量密度为40~200 m J/cm^2的飞秒激光与CuZr非晶合金的相互作用过程。低能量密度下,靶材的烧蚀机制主要表现为机械破碎;高能量密度下,热机械蚀除和相爆炸共同存在于靶材的烧蚀过程,随着能量密度的增加,相爆炸成为主要蚀除机制。利用径向分布函数分析了CuZr非晶合金结构的无序性,分析结果表明,激光能量密度由80 m J/cm^2增加到120 m J/cm^2时,飞秒激光与靶材相互作用过程中,材料内部的原子保持着无序状态,材料未发生明显晶化。

The femtosecond laser ablating CuZr amorphous alloy has been simulated using the molecular dynamics method combined with the two temperature model. The duration of laser is 100 fs and the fluence is selected from 40 mJ/cm2 to 200 mJ/cm2. At low laser fluence, the ablation mechanism of the target material is mechanical spallation. At high laser fluence, thermo-mechanical removal and phase explosion co-exist in the ablation process of the target material, and with the increase of the fluence, the phase explosion becomes the main removal mechanism. The disordering of CuZr amorphous alloy structure is analyzed by the radial distribution function. The results indicate that material atomics maintain a disordered state and no obvious crystallization is observed when the laser fluence increases from 80 mJ/cm2 to 120 mJ/cm2during ablation process.