The Influence of Predefined Grooves on the Gas Tungsten Arc Welding Performance of 7072 Aluminum Alloy

Aluminum alloys have low melting points and exceptional thermal conductivity, endowing them with significant weld deformation and shrinkage. This study delves into mitigating the heat-affected zones and welding-induced distortions of 7072 aluminum alloy after GTAW (Gas Tungsten Arc Welding). Specifically, the influence of the predefined grooves on the microstructure and mechanical performance of the weld joints were investigated. Meanwhile, the temperature distribution and melt pool flow of the predefined I-shape, unilateral V-shaped, and V-shape grooves during welding were simulated using ANSYS. Experimental results showed, the weld hardness from the center of the weld to both sides of the base metal is characterized by a “W” type distribution regardless the types of predefined grooves. The tensile fracture morphology of the V-groove welded joint exhibits the ductile fracture along the thickness. The tensile strength and elongation of the V-shaped groove were the highest (276.5 MPa, and 15.76%, respectively). Next, the I-shaped groove and single-sided V-shaped groove achieved tensile strengths and elongations of 271.7 MPa, 15.38%, and 224.95 MPa, 10.91%, respectively. By comparison, the I-shaped groove welding joints have a good bonding area, showing superior weld appearance and integrated mechanical properties. The unilateral V-groove welded joints showed a mixed tough–brittle fracture morphology and porosity defects in the middle of the weld joint. However, the unilateral V-groove welded joints had the highest microhardness of 132HV_0.2. Overall, the V-shaped joint demonstrates superior uniformity in microstructure and the most excellent mechanical properties.