Current-carrying wear behavior and the interface evolution of the Cu/Al tribological pair

Cu/Al tribological pairs play a crucial role in maintaining the efficient operation of a wide range of engineering components. However, their durability is often compromised by wear-induced damage, which involves the accumulation of material at the Cu/Al friction interface. This study investigates the intricate wear behavior of Cu/Al tribological pairs under electrical current, with a specific emphasis on material transfer events occurring at the interface. Our findings reveal that the applied electric current exerts a lubricating effect on the sliding contact friction, resulting in reduced adhesive wear. However, it concurrently exacerbates fatigue-induced delamination, abrasive wear, and electrical wear. Through detailed analysis of interface temperatures and microstructure characterizations, we demonstrate that Al deposit adhesion occurs through interfacial metal mixing and nanoscale diffusion in the presence of only mechanical friction. Conversely, at high electrical currents, interfacial melting transpires, resulting in robust adhesion facilitated by the formation of an intermetallic compound. Our findings offer valuable insights into the microscopic adhesion events occurring in Cu/Al tribological pairs and provide guidance for developing innovative coating systems aimed at reducing material deposition in Cu/Al current-carrying friction interfaces.