Abstract The work analyzes the effect of weld configuration on the load-bearing performance of TIG-welded joints in AA2219 aluminum alloy. The direct current electrode negative gas tungsten arc welding process was used to fabricate two types of joints, butt and lap, in optimum parameters. To assess the mechanical integrity of the joint, mechanical test was conducted to indicate that the lap joint had a better peak load capacity of 29.8 kN than 22.8 kN of butt joint due to the presence of higher effective load-bearing area. The butt joint showed higher load carrying capacity due to higher hardness in the weld metal and heat-affected zone. Microstructural analysis of both joints under low- and high-resolution imaging revealed differences in grain morphology and precipitate size. Fine and densely distributed precipitates were observed in the butt joint, whereas coarse and larger second-phase particles were observed in the lap joint. This difference may be attributed to variations in the thermal cycle during TIG welding. Fractographic examination also confirmed ductile fracture in the butt joint and quasi-cleavage fracture in the lap joint.
Paranthaman et al. (Tue,) studied this question.