Effects of Laser and Tungsten Arc Welding Processes on the Thermal Softening and Mechanical Properties of Almag6 Aluminum Alloy

Abstract

The adoption of aluminum in the mobile industry is driving development of aluminum alloys. Among the additive elements of aluminum alloy, magnesium is a crucial component commonly included in various commercial aluminum alloys. Because of its ability to enhance solid solution strengthening and work hardening, many researchers are investigating methods to increase the magnesium content in aluminum applications. Almag6 contains more than 6 wt% of magnesium and exhibits excellent structural properties; it possesses higher yield and tensile strengths than the commercial 5XXX series of aluminum materials. However, work-hardening alloys are vulnerable to welding heat. In this study, laser and tungsten arc welding processes were performed to study the effect of welding heat on the mechanical and microstructure properties of Almag6. It was found that the mechanical strength and hardness of the welds reduced significantly. Similar to other work-hardening aluminum alloys, the lowest hardness was measured in the fusion zone with a strength of over 200 MPa. Relatively low breaking strengths were measured in the tungsten arc welding specimens owing to grain coarsening in the welds.