Effect of laser shock processing on erosive resistance of 6061-T6 aluminum

Application of laser shock processing (LSP) on 6061-T6 aluminum was made in order to evaluate its response to the erosive wear by silica sand. Impact angles of 15°, 30°, 60° and 90° were tested, two particle speeds (37 and 58 m/s) and two LSP irradiation conditions were used. Erosion marks were characterized by 3D profilometry and SEM analysis was conducted to identify the erosion mechanisms for each tested angle. The results showed a maximum erosive wear at low impact angles (ductile type behavior). Erosion strength and the erosion mechanisms were not affected by the application of LSP and they were attributed to the high strain rate of the erosion phenomena. A few differences encountered on the erosion plots were explained on the basis of the surface roughness left by the LSP process. The maximum mass loss and the maximum erosion penetration happened in different impact angles (15° and 30°, respectively). Finally, a well-defined erosion mechanism transition was observed, from cutting action at low impact angle, to crater formation at 90° of incidence.