Investigation of corrosion-time effects on fretting wear behaviours of copper-magnesium alloy

Abstract

The premature failure of integral droppers was attributed to the environmental corrosion and fretting wear due to mechanical vibration. Due to its complex working environment, the research on the fretting wear of corroded copper-magnesium alloy is rarely reported in the literature. In this work, an experiment was designed to investigate the effect of corrosion time on the fretting wear behaviours of the copper–magnesium alloy (CuMg0.4) used in integral droppers. The running conditions fretting map of CuMg0.4 at dry conditions and room temperature were successfully constructed by fretting wear tests. Representative testing parameters from different fretting regions (i.e. partial slip, mixed slip and slip regimes) were selected to carry out fretting tests using the CuMg0.4 cylinder after salt spray corrosion for the first time. The running characteristics, wear morphologies and fretting damage mechanisms of tribo-pairs were analysed. Results indicated that the fretting wear mechanisms of CuMg0.4 included adhesion, oxidation, abrasive and fatigue wear mechanisms. After corrosion, the oxide layer on the matrix surface could avoid cracks in a short time, but with increased corrosion time, the overall wear degree of the specimen deepened, and the damage was aggravated. This work further provides theoretical basis for failure analysis and other aspects of integral droppers.