Influence of porosity on dry sliding wear behavior in spray deposited Al-6CuMn/SiCp composite

Dry sliding wear behavior of spray deposited Al-6Cu-Mn/13 vol.% SiCp compos ites in both as-sprayed and forged states has been studied. Wear mechanisms in different wear regions and the influence of porosity on wear behavior a re discussed. Within the applied load range of 5-400 N (corresponding norma l stress is 0.1-8 MPa), the variation of wear rate with applied load in the as-sprayed composite can be divided into three wear regions, while the as- forged composite four wear regions. A transition load from mild to severe w ear could be observed with increasing load. Severe wear was controlled by a dhesion mechanism. Mild wear was associated with three different mechanisms : oxidation, delamination and subsurface-cracking assisted adhesion wear. T he wear resistance of the as-sprayed composite was similar to that of the a s-forged composite at lower loads. However, at higher loads, the as-sprayed composite had a higher wear rate and small transition load, therefore, exh ibited inferior wear resistance than the as-forged composite. At lower load s, pores beneath the worn surface of the as-sprayed composite were stable a nd could not propagate significantly. Therefore, porosity displayed a very small influence on dry sliding wear behavior of the composite. At higher lo ads, the pores beneath the worn surface became unstable and the cracks orig inated from these pores could propagate during wear process, resulting in a higher wear rate and smaller transition load. (C) 2000 Elsevier Science S. A. All rights reserved.