The influence of oxygen and water vapour on the friction and wear of an aluminium alloy under fretting conditions

Abstract

An investigation was conducted to determine the effect of oxygen and water vapour on the friction and wear behaviour of an Al-Zn-Mg alloy under fretting conditions. Fretting wear experiments were carried out in wet air, dry air and in dry argon. In this case the peak-to-peak relative slip amplitude was varied from 20 to 260 μm to determine the critical slip amplitude of fretting wear in these environments. The experimental results indicated that the wear rates in dry air and in dry argon under macroslip conditions were almost the same and quite lower than the wear rate in wet air. This revealed that the effect of oxygen on fretting wear was not large but that water vapour accelerated the fretting wear of the aluminium alloy. The cyclically softened material due to overaging was observed below the contact surface during fretting in wet air. The mechanism involved rapid fretting wear in wet air which caused the removal of a heavily work-hardened layer as it was formed but the softened material below it was not removed.