Microstructure and mechanical properties of high power CO2 laser welded joint of Mg-Rare earth alloy NZ30K

The weldability of a 9.5 mm thick Mg-Rare earth alloy NZ30K using 15 kW high power CO2 laser was studied. The microstructure and mechanical properties of the typical welded joints had been analyzed and tested. When using the right laser welding parameters, good weld forming can be obtained. The microstructure of the fusion zone is small equiaxed grains. There is no softening zone to be observed according to the micro-hardness distribution across the welded joints. The results show that the thick Mg-Rare earth alloy NZ30K plate can be welded by the high power CO2 laser with good weld quality.