Process selection for dissimilar AA6082-AA2014 aluminum joints: Comparative evaluation of TIG, CMT and FSW

This study comparatively evaluates tungsten inert gas (TIG), cold metal transfer (CMT), and friction stir welding (FSW) for AA6082-AA2014 dissimilar joints using two parameter levels per process. TIG at 210 and 230 A, CMT at 180 and 200 A, and FSW at 40 and 80 mm/min traverse speeds at 1000 rpm. The weldments were assessed through tensile testing, Izod impact testing, Vickers microhardness, SEM morphology, dry sliding wear, coefficient of friction, wear rate, specific wear coefficient, potentiodynamic polarization, and one-way ANOVA. FSW2 delivered the best mechanical performance, with an ultimate tensile strength of 241.81 MPa, yield strength of 177.81 MPa, elongation of 11.57%, impact energy of 34 J, weld zone hardness of 109.04 HV, and joint efficiency of 73.28%. CMT2 showed intermediate performance, achieving 199.85 MPa UTS, 14.21% elongation, 29 J impact energy, and 96.19 HV hardness, whereas TIG1 gave the lowest tensile strength of 168.63 MPa. Wear resistance followed the order FSW2 > FSW1 > CMT2 > CMT1 > TIG2 > TIG1, with FSW2 reducing wear rate by approximately 88.5% relative to TIG1. Corrosion resistance based on corrosion rate followed CMT2 > CMT1 > FSW2 > FSW1 > TIG1 > TIG2. ANOVA confirmed that welding condition significantly affected all evaluated responses (p < 0.001). The findings establish FSW as the most balanced route for structural performance and wear resistance, while CMT offers a lower heat fusion alternative when solid-state processing is impractical.