Investigation of residual stress profiles induced by laser shock peening

Abstract

This study compares the residual stresses formed on samples before Laser Shock Peening (LSP) and after mechanical relaxation of LSP. Sample material used in the analysis is Aluminum Alloy of grade 6061 with no prior heat treatments done. Experimental results on surface residual stresses were measured for samples of varying thicknesses of 3mm, 5mm and 10mm. To achieve more diverse results, different power densities were used in the experiments, 2.65, 1.33 and 1.15 GW/cm^2. Experimental procedures used to achieve mechanical relaxation of residual stresses were Axial fatigue test and 3-point bending test. It was observed, with the aid of an X-ray diffraction machine and Prism drilling, that there were significant increase in the fatigue life and improvements on the residual stress relaxation of the samples that has undergone the fatigue and 3-point bend test.