THE EFFECTS OF WELDING PRESSURE AND REINFORCEMENT RATIO ON WELDING STRENGTH IN DIFFUSION-BONDED AlMg3/SiCp COMPOSITES

Abstract

In this study, using the diffusion welding method, welded joints were created with AlMg3/SiCp composite materials, and the mechanical strengths of these joints were examined. The AlMg3/SiCp composite specimens were cut out of plates produced directly with the semi-solid stir-squeeze casting method and contained 10% SiCp and 20% SiCp reinforcement. To examine the effects of reinforcement ratios on joint strength, specimen couples with the same and different reinforcement ratios were created. To examine the effects of different welding pressures on joint strength, by keeping the welding temperature constant at 580°C, welding was performed under 3 different pressures as 1.5 MPa, 2.5 MPa and 3.5 MPa. By determining the mechanical strengths of the welded joints that were formed by shear test, the effects of reinforcement ratios and welding pressures on joint strength were investigated. As a result of the shear tests applied on the welded specimens, in the specimens that were diffusion-welded, welding quality decreased based on increasing reinforcement ratios, but as the amount of pressure and application duration increased, joint strength increased. As the SiC ratio increased in the joint zones, diffusion became difficult, and weak joints were obtained. The microscopic structure of the joint zone was examined by using optical microscopy and scanning electron microscopy (SEM). It was seen that diffusion welding could be successfully performed in bonding SiCpreinforced aluminium composites if the suitable welding pressure and duration are selected.