Development and Tribological characterisation of Friction Stir Spot Welded Joints of dissimilar metals

Abstract

This research In the present work, the development and tribological characterization of Friction Stir Welding joints between dissimilar metals, i.e., pure aluminum (Al1060) and copper (C11000), was investigated. FSW primarily produces defect-free, solid-state joints; however, only a few research studies have focused on the tribological properties of dissimilar Al–Cu welds. In the present study, D2 steel tools were employed, and welding was performed on nine different specimens produced in accordance with L9 Taguchi orthogonal array to evaluate the influence of shoulder diameter, rotational speed, and welding speed on friction force and wear rate. The produced weld specimens were processed with pin-on-disc method to determine the friction and wear behavior for weld joint. It was found that the material plasticization was greatly improved with the increase in shoulder diameter and rotational speed, leading to the reduced friction force and wear rate. Increasing the welding speed not only reduced the heat input but also enhanced tribological stability. The smallest friction force and wear rate were achieved under the condition of 22 mm shoulder diameter, 1200 rpm rotational speed, and 150 mm/min welding speed. The SEM analysis shows progressive subsurface cracking and material removal under the applied load and sliding conditions. This work presents a clear relationship between FSW process parameters and tribological performance, thus providing significant implications for the development of long-life dissimilar metal joints regardless of industrial applications.