Abstract: High power laser + pulsed gas metal arc welding(GMAW)hybrid welding is an advanced welding process in manufacturing light weight structures. For aluminium alloys, its reflection rate is much higher than steels, thus, the previous keyhole model for steels has to be modified. With considering the characteristics of high power laser+pulsed GMAW hybrid welding of aluminium alloys, the effect of metal steam plume and laser-induced plasma on the laser power absorption inside keyhole is dealt with, the previous model of keyhole profile is improved, and the calculation accuracy of laser-induced keyhole profile is enhanced. The distribution parameters of volumetric heat source for laser beam are calibrated by using the calculated keyhole profile. The predicting model of weld shape and size is established to determine the weld dimensions in hybrid welding of aluminium alloys. Through numerical analysis of temperature field and weld geometry, the data about the weld formation in hybrid welding of aluminium alloys are obtained under different conditions. High power laser + pulsed gas metal arc hybrid welding experiments validate that the calculated results are in good agreement with experimentally measured ones.

Key words: Aluminium alloys, Experimental validation, Hybrid welding, Weld shape and size prediction