冲击波在膜基结构材料中传输的研究

Study of Laser-Driven Shock Wave Propagation in Film-Substrate Structure Material

将Abaqus模拟与实验相结合,研究了激光诱导冲击波在膜基结构材料中的传输及其对膜层-基体结合强度的影响。建立不同声阻抗匹配模式的膜基结构模型,改变膜层厚度,分别进行模拟和实验。分析不同时刻深度方向的应力分布,膜层脱落的凸起形貌,不同膜层厚度对应的最大应力值、持续时间。结果发现:当膜层声阻抗小于基体时,膜层表面覆盖合适的约束层,可以避免膜层-基体界面处形成拉应力,两者结合强度不会减弱,材料表面性能得到强化;当膜层声阻抗大于基体时,应根据加工要求,决定是否可以进行激光冲击;当拉应力不可避免时,膜层厚度需慎重选择,既要考虑材料表面的强化效果,也要减小界面处拉应力强度。

In order to study laser-induced shock wave＇s propagation properties in the film-substrate structure material and its impact on film-substrate bonding strength,the process is studied systematically based on Abaquas software and experiments.In the numerical simulation,the film-substrate structure models with different acoustic impedance matching modes are established and the film thickness is changed.The stress distribution along the depth direction at different moments,the convex morphology of films,the maximum stress value and duration of different thickness films are all analyzed.The results show that,when the acoustic impedance of the film is weaker than that of the substrate,tensile stress at the interface between the film and substrate can be avoided by covering appropriate constraint layer on the film surface.In this case,the bonding strength is not weakened and the material surface properties are enhanced.When the acoustic impedance of the film is stronger than that of the substrate,conducting the laser shock or not depends on the processing purposes.When the stress is unavoidable,choices of material thickness should be cautious.Not only the strengthening effect of the material surface should be taken into account,but also the tensile stress at the interface between the film and substrate should be reduced.