抄録
This paper describes high-quality welding of magnesium alloy. At first welding defects were restrained by pulse wave pattern control. Next, the defects were restrained by irradiating simultaneously two beams. The pulse wave YAG laser beam and continuous wave YAG laser beam were combined to irradiate the magnesium alloy. One factor of porosity and crack formations was the remain of metal plasma inside the molten zone by steep collapse of a keyhole. Therefore, the welding defects occurred easily only in the pulse YAG laser welding. Then, the keyhole was formed by the pulse wave YAG laser beam, and the CW laser was combined to prevent rapid cooling. As a result, the cracks and the porosities structure were completely restrained, and the melt diameter and the penetration depth increased.
