Wear behaviors of Cf/Mg composites fabricated by extrusion directly following vacuum pressure infiltration technique

Cf/Mg composites were fabricated by extrusion directly following vacuum pressure infiltration technique (EVI). Fiber distribution and wear behaviors of the composites were investigated. For comparison, Cf/Mg composites were also fabricated by squeeze casting as references. Dry wear tests were carried out at room temperature under a normal load of 100 N, at a sliding velocity of 0.47 m/s for sliding distances up to 2000 m. Worn surfaces were observed under SEM to understand wear mechanisms. The results indicated that wear rates of squeeze-casting composites were higher than those of as-extruded composites (fabricated by EVI). The main wear mechanisms of the squeeze-casting composite were delamination wear. Fiber orientation with respect to sliding direction had a remarkable influence on the wear rates. With fiber orientation paralleled to the sliding direction, the wear rate of composites was higher, compared with that when fiber orientation inclined to the sliding direction. Correspondingly, carbon fibers on the worn surface were pulled out and fractured, respectively. The main wear mechanisms of the as-extruded composites were abrasive wear and fiber fracture. In addition, partial delaminations were found on the worn surface, when fiber orientation was parallel to the sliding direction. With fiber orientation perpendicular to the sliding direction, the wear rate of composites was somewhat lower than that when fiber orientation was parallel to the sliding direction.