Laser- and electron beam welding of magnesium alloys

Designing and constructing complex structures using magnesium raises the ne cessity to solve joining problems. Laser beam welding and electron beam wel ding are two methods which are very fast and allow short clock cycles. Toge ther with fast magnesium processing like dir casting and extrusion pressing these welding methods help to increase productivity and reduce production costs. The experiments were carried out on two different electron-beam-weld ing machines: while some of the experiments took place on a conventional hi gh-vacuum electron-beam welding machine (EBW), a nonvacuum electron-beam we lding machine (NVEBW) was used to weld under atmospheric pressure condition s. The laser beam welding experiments were carried out with CO2- and Nd:YAG -Lasers. The investigations show that beam welding of magnesium-wrought and die-cast alloys is possible without crack formation. The mechanical proper ties of the welded wrought alloys were in the range of the base material. O nly the fracture strain of the joints was reduced. When welding die-cast al loys, the formation and the properties of the a welding joints were determi ned by the quality of the base material, such as pore content and contamina tion of the alloys. Thus, using vacuum die-cast alloys with high purity can reduce the porosity within the joining zone. By the use of wire filler mat erial the quality of the welding seam could he improved, because the porosi ty was reduced, and the vaporising material was compensated.