Evaluation of diffusion welding of 6061 aluminum and AZ31 magnesium alloys without using an interlayer

In this research, in order to join 6061 aluminum and AZ31 magnesium alloys without using an interlayer, the diffusion welding method was used. The tests were performed in temperature of 430-450 degrees C for 60 min and under pressure of 29 MPa in vacuum of 1 x 10(-3) torr. Microstructural studies and determination of phase combinations in interfacial bonding were done by using of scanning electron microscopy (SEM). Mechanical properties of joints were measured by using a Vickers microhardness and shear strength. The results of studies have revealed a successful join between two alloys and confirmed the presence of different reaction layers in the diffusion zone. The chemical composition of these layers was determined by Energy-dispersive X-ray Spectroscopy (EDS). The formation of intermetallic compounds such as Al12Mg17 and Al3Mg2 was predicted by use of the phase diagram of aluminum-magnesium. According to the studies performed, interfacial transition zone ( ITZ) with 23 and 27 mu m thicknesses were formed respectively at 440 and 450 degrees C and the maximum amount of bond strength, 42 MPa, was achieved at 440 degrees C which was due to the suitable coalescence of metal surfaces. (C) 2014 Elsevier Ltd. All rights reserved.