Analysis of Explosively Welded Aluminum–AZ31 Magnesium Alloy Joints

Abstract

The joining of wrought magnesium alloy AZ31 and commercially pure aluminum A1100 plates was performed using explosive welding technique. Several welds were made by changing the experimental parameters. Optical microscopy and scanning electron microscopy were employed to observe the morphological and microstructural variations at the interface boundary. The geometry of the interfacial profile varied from smooth to rippled form with increase in the level of kinetic energy delivered to the bonding zone. The microstructure at the boundary was free of porosity and showed unique diffusionless dissimilar bonding. Localized zones of solidified melt in some cases were observed in the vicinity of the bonding line of the wavy-interfaced welds. Elemental analysis revealed the complex intermixed microstructure of these regions, accompanying with compositional variation due to formation of the metastable intermetallic phase Al₂Mg. The bonding strength of the welds, evaluated through shear tests, confirmed the high quality of the joints produced. Based on the experimental results the lower limit of the welding parameters which ensure achieving a satisfactory joint is proposed.