Influence of porosity on dry sliding wear behavior in spray deposited Al–6Cu–Mn/SiC p composite

Abstract

Dry sliding wear behavior of spray deposited Al–6Cu–Mn/13 vol.% SiC p composites in both as-sprayed and forged states has been studied. Wear mechanisms in different wear regions and the influence of porosity on wear behavior are discussed. Within the applied load range of 5–400 N (corresponding normal 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 wear could be observed with increasing load. Severe wear was controlled by adhesion mechanism. Mild wear was associated with three different mechanisms: oxidation, delamination and subsurface-cracking assisted adhesion wear. The wear resistance of the as-sprayed composite was similar to that of the as-forged composite at lower loads. However, at higher loads, the as-sprayed composite had a higher wear rate and small transition load, therefore, exhibited inferior wear resistance than the as-forged composite. At lower loads, pores beneath the worn surface of the as-sprayed composite were stable and could not propagate significantly. Therefore, porosity displayed a very small influence on dry sliding wear behavior of the composite. At higher loads, the pores beneath the worn surface became unstable and the cracks originated from these pores could propagate during wear process, resulting in a higher wear rate and smaller transition load.