Microstructure and Mechanical Properties of Dissimilar Joints of AZ31 MG Alloy to Aluminium Alloys

Abstract

In attempts to improve the performance of dissimilar joints between AZ31 Mg alloy and different Al alloys, solid state joining processes such as Magnetic Pulse Welding (MPW) and Friction Stir Welding (FSW) were applied for minimizing the formation of brittle intermetallic phases. MPW process has been concentrated mainly on round section tube to tube and tube to bar welds. Mg alloy AZ31 has been successfully welded to pure Al A1070 as well as to Al alloy A3003. Tensile test clearly showed the MPW welds were stronger than the weaker of the base metal so failure occurred in aluminum base metal. While FSW process for the dissimilar joint between AZ31B/A6061 alloys with a thickness of 2mm revealed optimum weldability under the conditions of travel speed of 0.8mm/sec and tool rotation speed of 850rpm. For the sound dissimilar joint, the maximum tensile strength of 179 MPa, which was about 80 % of the Mg base metal tensile strength, has been obtained.