Effect of process parameters in friction stir welding of dissimilar magnesium alloys

The high reactive nature of magnesium alloys impose restriction during fusion welding and make it difficult to fabricate. Due to inherent characteristics, solid-state friction stir welding may be a suitable option for joining these alloys. But welding of dissimilar alloys is again a difficult task. This study suggests significance of different welding parameters on friction stir weld quality of dissimilar AZ31 and AZ91 magnesium alloys at different welding conditions. The study also helps in achieving an optimum welding range for better surface, mechanical and metallurgical properties. The best experimental value of surface roughness, grain size, tensile strength, microhardness and flexural strength was obtained as 3.398 µm, 8.1050 µm, 234.86 MPa, 72.508 Hv and 380.065 MPa, respectively. Intermetallics were absent in the weld zone, while maximum joint efficiency (89.71%) was better than the previously reported research. The optimized research outcomes suggest improvement in surface finish, tensile and flexural strengths.