The adhesive wear process was analyzed microscopically by successive observations in the SEM. Fractographic analysis of the transferred fragment was also conducted. Two modes of adhesive transfer were identified. In the first mode, successive slip occurs on the slip planes within the prow and forms an extrusion called “slip-tongue.” A shear crack subsequently propagates from the root of the slip-tongue. In the second mode, successive plowing takes place at the head of the wedge by accompanying the shear crack growth at its trailing end. In both cases, cracks produce a dimpled fracture surface. It was also found that the fragment transferred from the sharp asperity to the blunt asperity. The slip line field solution was introduced to explain the shape effect on wear.
