Abstract
This paper describes the welding process in which the pulse wave YAG laser and continuous wave YAG laser are combined to irradiate the magnesium alloy. One factor of porosity and crack formations is the remains of metal plasma inside the molten zone by steep collapse of a keyhole. Therefore, the welding defect occurs easily only in the pulse YAG laser welding. Then, the keyhole was made from the pulse wave YAG laser, and the CW laser was combined to prevent cooling rapidly. The effect on the decrease of the crack and porosity formation was investigated. As a result, the crack decreases clearly, and the melt diameter and the penetration depth have increased.
