Laser ablation mechanism and parameter effects of SLM-fabricated GH3625 treated by microscale laser shock peening without coating

Selective laser melting (SLM) offers great potential for fabricating complex metallic components. However, poor surface integrity limits their practical applications, especially in regions where machining is infeasible. In this work, microscale laser shock peening without coating (μLSPwC) is innovatively applied to improve the surface integrity of SLM-fabricated components. The laser ablation mechanism and parameter effects were investigated. The results indicated that μLSPwC effectively eliminated surface defects, lowering the defect density from 13.25 % to 0.49 % and the surface roughness from 7.75 μm to 6.05 μm. Furthermore, a compressive residual stress (CRS) layer with a depth of 460 μm was introduced, while the hardened layer extended to 270 μm, with the surface microhardness increasing by 39.4 %.