Investigations on mechanical features and mechanical performance of rotary friction welded Al-Cu joint at optimized conditions

Abstract

In this experimental investigation, rotary friction welding (RFW) was employed to fabricate dissimilar Al-Cu joints, and the RFW variables were rotated against the ultimate tensile strength (UTS) in an effort to strengthen the dissimilar AA1100 and pure copper (Al-Cu) joint using response surface methodology (RSM) with a three-factorial design. Following this, micro-hardness, metallurgical characterization, and fatigue properties studies were done on the dissimilar joints fabricated under the optimized conditions. As a result of this investigation, the UTS of 208 MPa was attained as a maximum as the rotation speed was set at 1800 rpm, the friction time was 10 s, and the forging load was 5 kN. The dissimilar joint exhibits a better fatigue strength of 98.5 MPa when compared to the AA1100 base metal. At optimized conditions, the feature of the fracture image was found to be brittle due to the development of new compounds in the weld interface. A significant dip in micro hardness (52 Hv) was noticed in the region that connects TMAZ and HAZ of the AA1100 side of the dissimilar joint, which was concluded to be the weakest zone as the dissimilar joints were fractured in the same location during the tensile test. The observed results benefit the automotive sector, especially when fabricating components that require effective thermal management and weight reduction, like electrical connectors, heat dissipation systems, and radiators. For heat exchanger applications, improved fatigue strength in dissimilar Al-Cu joints is important because it guarantees longer structural integrity and improved durability.