Structure and Mechanical Properties of ADC12 and A5083 Dissimilar Friction Stir Welded Joints

摘要

Friction stir welding (FSW) is a relatively new solid-state joining process. This joining technique is a green technology due to its energy efficiency, environment friendliness, and versatility. In this study, the structure and mechanical properties of ADC12 die casting alloy and A5083 dissimilar joints welded by FSW under different welding conditions were systematically investigated. The micro-structural refinement of silicon particles was found obviously in the stir zone. The Vickers hardness levels of the ADC12 and A5083 base metal were 95 ± 10 and 80 ± 5 Hv0.1, respectively. Distinctly different Vickers hardness levels from 80 to 120 Hv0.1 were produced corresponding to various micro-structural features in the stir zone. The transverse tensile failure of the prepared sound joints occurred at the ADC12 base metal, which means that the tensile strength of the joints was higher than 250 MPa. Although the fractured surface of ADC12 base metal exhibited a few big river patterns, it showed mainly big dimple patterns in which small river patterns were observed. At the welding speed of 4.17 mm/s and downward force of 12.3 kN, the longitudinal tensile strength and elongation of the stir zone were 347 MPa and 11.6%, respectively.