Study of laser-driven shock wave propagation in film-substrate structure material

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. © 2016, Chinese Lasers Press. All right reserved.