Investigations on friction stir welding of AZ61A magnesium alloy

Abstract

Magnesium is a lightest structural alloy which has been widely used in transportation industries mainly due to their low density and high strength to weight ratio In addition magnesium alloys have good castability sound damping capabilities electromagnetic interfere shielding properties excellent machinability and recyclability However to further expand the application of magnesium alloys more effective welding and joining techniques are required Joining of magnesium alloys by conventional welding techniques is very difficult due to the problems such as cracking expulsion and void formation in the weld zone The drawbacks associated with fusion welding include complex thermal stresses and severe deformation the presence of porosity and crack in the fusion zone the excess eutectic formation Gas Tungsten Arc Welding of magnesium alloys produced some defects such as porosity and hot crack which deteriorate their mechanical properties Friction Stir Welding is capable of joining magnesium alloy without melting it and thus can eliminate problems related to the solidification As an emerging joining technique friction stir welding has great potential for magnesium alloys since it can significantly reduce weld defects such as oxide inclusions porosity cracks and distortions commonly encountered in fusion welded joints newline