Helium bubble formation in YAG laser weldment of helium-implanted stainless steel

摘要

The helium bubble formation in YAG laser weldment of helium-implanted austenitic stainless steel was investigated. The helium ion implantation was carried out at the acceleration voltage from 2 to 6 MeV using an implantation apparatus. After the welding, helium bubbles were observed at the bond region, heat-affected zone and weld metal. The increase in the laser power caused the growth of helium bubble along the dendrite cell boundary in the weld metal. A cross bead welding was performed for repair welding after the helium implantation. The helium bubble formation was also observed at the interface between the first and the second bead. It has been shown that the helium bubble formation in the weld metal and in the heat-affected zone during repair welding can be reproduced through the helium-implanting technique.