Effect of friction stir welding on mechanical properties and fracture mechanism of 7B52 Al laminated composite

Abstract

Abstract-Aluminum laminated composite (ALC) is a new type of structural material with a broad application space and development prospects. Due to the laminated structure, the mechanical properties and failure patterns of ALCs differ significantly from those of uniform materials. The friction stir welding (FSW) of Al alloy can effectively avoid many defects caused by fusion welding, but the FSW of ALCs is in its infancy stage. Friction stir welding experiment of 7B52 ALC was carried out in this study. The Vickers hardness test, tensile test and impact test were performed on the specimens of the joint and base metal to analyze the effect of friction stir welding on microhardness, tensile properties and impact properties. The fracture surfaces were observed by SEM to investigate the fracture mechanism. A defect free weld was obtained. However, the laminated structure was destroyed, resulting in the decrease of microhardness and tensile strength. The microstructure of the weld was improved, significantly increasing the impact toughness.