Surface damage mechanism and evolution of Al-Zn-Mg-Cu alloy as a sliding electrical contact material under extreme environments

Abstract

Due to the coupling effect of electric-magnetic-heat-force field, the complexity of electrical contact surface damage increases, and a clear understanding of the damage mechanism under harsh operating conditions is urgently required. In this study, the damage behaviors and evolution law of Al-Zn-Mg-Cu alloy against Cu-Cr-Zr alloy as a friction pair were analyzed through sliding electrical contact tests using various current loads. The results indicated that at lower current loads (<350 kA), the surface damage of the Al-Zn-Mg-Cu alloy was characterized by current-carrying plow due to mechanical wear. At medium current loads (350 kA–550 kA), the surface characteristics were dominated by mixed damage, featuring both current-carrying plows and heat melting of the surface. However, at high current loads (>550 kA), the surface damage was mainly caused by melting. The mass loss of the material exhibited an increasing trend with the current, with a mass loss of 0–0.2 g for the currents less than 350 kA, 0.2–0.8 g for the currents in the range of 350–550 kA, and 0.8–1.0 g for the currents exceeding 550 kA.