Effects of sliding conditions on wear by repeated contact of two asperities

Effects of sliding conditions on wear of ductile metals under repeated sliding of two diamond pyramidal asperities along close tracks were studied by using a dual-pin/disk test rig. Brass worn by cutting both with one asperity and with two asperities, whereby wear increased linearly with sliding cycles and showed little dependence on the distance between the two grooves. Aluminum and copper exhibited characteristic wear behavior due to plastic deformation of the central ridge between neighboring grooves, which was not observed in the sliding of one asperity. Progressive plastic deformation on the ridge surface gave rise to an extrusion at its tip, which eventually detached from the ridge to form elongated wear particles. In this deformation-oriented type of wear, larger distance between the grooves caused deeper grooves but less wear after fifty cycles of sliding, and the amount of wear approached a certain limit as the sliding cycles increased. A simple model of track geometry that determined the upper limit of wear by plastic deformation was proposed, with which dependence of the wear amount on the groove distance and normal load was explained.