Abstract
Laser welding, regarded as one of the welding techniques for use with steel materials and employed in the fabrication of automobiles, has increasing applications in the manufacture of transmission systems and car bodies; however, there are not many examples of application to aluminium alloy components.1 The reasons for this are thought to be as follows: aluminium alloys have a higher laser reflectivity compared with that of steel materials; consequently an even higher power laser is required to input energy to the material for welding and also, due to the low viscosity of molten aluminium alloy, stable welding is difficult.2,3