Experimental investigation into cavitation erosion characteristics of stainless steel caused by laser-induced bubbles

To explore the degree and mechanism of damage inflicted by cavitation bubbles in the vicinity of the wall, stainless steel was chosen as the wall material in this study. Laser-induced bubbles were then generated at a specific distance above the stainless steel wall. The surface damage morphology of the material was analyzed using scanning electron microscopy and a three-dimensional contour scanner. We observed the phenomenon of shockwave self-focusing that occurs when cavitation bubbles collapse near the wall. This shockwave self-focusing is identified as the decisive mechanism underlying cavitation erosion. Additionally, the results indicate that the projection of the bubble center on the material surface does not overlap with the cavitation erosion region, implying that the microjet is not the main cause of cavitation erosion. Cavitation bubble collapse causes significant erosion on the surface when the stand-off distance γ is less than 0.5. Finally, we conducted a quantitative analysis of the energy density of the collapse shockwave, the number of bubble collapses, and the volume loss of the cavitation erosion area. It is found that the cavitation erosion volume follows an exponential relationship with the product of the number of bubble collapses and the shockwave energy density.