The effect of laser shock peening with different absorbing coatings on the hardness of aluminum alloy

During laser shock peening, the pulsed laser with high energy is irradiated on the surface of the absorbing coating, after which the laser induces a plasma explosion. The plasma explosion could induce a shock wave with high peak pressure much higher than the yield strength of metal samples so that the plastic deformation can be formed after laser shock peening. After laser shock peening on metal materials, the shock wave could form compressive residual stress near the surface of the sample, which is beneficial for the mechanical properties. The hardness tester is used to measure the hardness of the sample with and without laser shock peening. The results of hardness could be used to analyze the effect of absorbing coating on shock wave. The study of laser shock peening with different absorbing coatings, such as black tape, aluminum tape, and paint coating, could help the application of laser shock peening for metal parts with complex shapes.