Experimental investigation on distribution of residual stress induced by intense laser

Laser shot peening is a novel technique that impresses compressive stress into the surfaces of metals or alloys.In this study,the mechanism of residual stress was investigated,and the experiment of the aeronautic aluminum alloy samples shocked by laser was carried out.The aluminum sample dimension was 30 mm×30 mm×5.5 mm.The pulse laser parameters were as following: wavelength 1.06 μm,duration 23 ns,and laser fluence 10~8~10~9 W/cm~2.The residual compressive stress induced by laser was compared with that induced by traditional shot peening.The results show that both the magnitude and the depth of residual stress increase with laser fluence and numbers of laser shot.The depth of residual compressive stress induced by laser is three to four times as that induced by traditional shot peening.