The forming of microgroove in copper foil on multiple laser-induced cavitation impacts

Abstract

A method to fabricate microgrooves using laser-induced cavitation shock forming is proposed. In this paper, the deforming behavior of copper foil is investigated using the experimental approach of multiple impacts of laser-induced cavitation bubbles. The microgroove structure was characterized by laser scanning confocal microscopy and scanning electron microscopy. As the number of impacts increase, the forming depth gradually decreases due to work hardening and loss of impact pressure. However, the surface roughness at the bottom of the microgroove increases and is covered with an oxide layer. The thickness and hardness distributions of the cross-section of the formed micro-groove are also studied. The results demonstrate that the maximum thickness thinning occurs at the bottom of the micro-groove, and the thickness reduces from 50 μm to 14 μm. The hardness of the material rises to varying degrees along the cross-section, and as the number of impacts grows from one to four, the hardness value rises from 1079 MPa to 2420 MPa.