Laser Welding of Magnesium Alloys

Aiming at establishing a reliable welding technique for magnesium alloys, the laser weldability of different types of magnesium alloys has been investigated using a high-brightness disc laser. It was found that high quality joints could be fabricated in the case of wrought type alloys when a certain defocusing level was optimized for the employed high-brightness laser beam of the newly developed diode-pumped solid-state laser. Porosity formation in the case of die-cast type alloys was extensively studied, and it was revealed that the gases entrapped in the base material during the die-casting process grew much larger. It was also found in the case of powder metallurgy alloys that the base material produced an extremely porous weld metal due to the gases entrapped in the production processes. While a significant reduction in porosity formation could be realized by the insertion of extruded alloy sheet in butt welding of die-cast alloys, the higher pressure levels applied in the production of the powder metallurgy type alloys made fusion welding of this alloy very difficult.