Mechanics of subsurface void nucleation in delamination wear

Abstract

An analysis of the mechanics of void nucleation around subsurface hard particles during delamination wear is presented. The analysis is based on the state of subsurface stress and the accumulation of plastic deformation after each passage of a slider asperity. It is shown that voids can only nucleate in a small region below the sliding contact and that the depth of this region increases with increases of both the normal load and the friction coefficient. Under a given situation, voids first nucleate in a small region below the surface after 1–10 asperity passes. During subsequent passes void nucleation becomes possible deeper below the surface. The number of passes required for void nucleation at a given depth is found to decrease with increasing friction coefficient. The analysis indicates that either void nucleation or crack propagation can control the wear rate depending on the materials and the sliding conditions.