Al4C3 formation and joint tensile properties of dual-beam laser butt welding SiCp/6005A composite with filler wires

Abstract

SiC-reinforced aluminum metal matrix composite (SiC/Al MMC) is one of the most promising structural materials that provide excellent specific modulus and weight reduction for industrial applications. When fusion welding of SiC-reinforced Al MMC, however, mechanical properties of SiC/Al MMC were significantly deteriorated due to the formation of brittle Al4C3. In this paper, a dual-beam laser welding process was developed to laser weld SiCp/6005A Al composite with ER4043 and ER5356 filler wires. The morphology, microstructure, tensile properties, and fracture behaviors of the welded joints were investigated. Compared to ER5356 filler wire, the weld quality was improved by ER4043, including better surface quality, fewer weld defects, higher tensile strength and better ductility. By introducing the silicon element of ER4043 filler wire into the molten pool, the size and amount of brittle Al4C3 compounds and the porosities were reduced and the reaction between liquid Al and reinforced SiC particles was suppressed to some extent. Furthermore, the dual laser beam energy ratio was optimized to 90%:10% (90/10), the tensile strength of the joints produced with ER4043 was significantly improved to 209 MPa, reaching 70% of the ultimate strength of the base metal.