Laser shock peening of aluminium alloys to enhance surface properties

Abstract

Laser Shock Peening (LSP) is a process where high energy nanosecond laser pulses are used to modify surface characteristics of treated materials. In this work, the LSP process is briefly explained and its effects on roughness, hardness and residual stresses of aluminium alloy 5083 are demonstrated. The LSP process is based on small plastic deformation caused by laser impacts on the surface which naturally increases roughness. It has been shown that the increase in roughness can be partially mitigated by strategic overlapping of individual laser pulses. The hardness of the peened surface has been increased by 19% and uniform compressive residual stresses up to 200 MPa have been created over a large area. The compressive stresses reached about 1.2 mm deep inside the samples.