Dry sliding wear behavior of A356-15 Pct SiC p composites under controlled atmospheric conditions

Abstract

The present investigation was carried out to provide a deeper insight into the mechanism of wear behavior of A356-15 vol pct SiCp composite under controlled argon and oxygen atmospheres through a detailed characterization of worn surfaces and subsurfaces. Dry sliding wear tests were performed for both as-cast and T6-treated specimens using a pin-on-disc machine with three sliding velocities (0.5, 1, and 2 ms−1) and three loads (1, 2, and 3 MPa). The wear rate of A356-15 vol pct SiCp composite was lower by nearly one order of magnitude under argon atmosphere compared to the specimens tested under oxygen atmosphere for all experimental conditions. Under argon atmosphere, the mechanism of material removal was by delamination wear and did not change within the parametric regime. In the case of the specimen tested under oxygen atmosphere, the wear behavior of the composite depended on the experimental conditions. At low load and low sliding velocity, the material removal was by abrasion. While at high load and high sliding velocity, the material removal mechanism was by delamination wear. Further, the mechanical mixed layer (MML) formed under argon atmosphere was more stable and homogenous compared to that formed under oxygen atmosphere. The MML formed under both atmospheres revealed much less in Fe content.