Subsurface properties of laser peened 6061-T6 Al weldments

A high power Q switched laser system has been used to laser shock process or 'laser peen' heat affected zones in a welded 6061-T6 aluminium alloy specimen. The effect of laser peening on hardness and elastic modulus versus depth and location with respect to the weld centre of the 6061-T6 specimen with 5083 and 5356 weld filler alloys has been analysed. Two laser energy densities, 100 and 200 J cm -2 , with water as a containment layer, were used to laser peen the metal specimen. In addition to increasing the hardness of the metal the treatment also affected the elastic modulus, and the affected depth varied with respect to the distance from the weld centre.