Abstract:The in-situ Al-based composites with different SiO₂/C/Al molar ratios were fabricated by reaction hot pressing. The dry sliding wear characteristics of the composites were investigated using a pin-on-disc wear tester. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to investigate the surface composition and its morphology. The results show that when the SiO₂/C/Al molar ratio is 3:6:9, more in-situ synthesized Al₂O₃ and SiC along with Si particles are produced, and Al₄C₃ is prevented completely from the Al-SiO₂-C system. Thereby, a significant improvement of wear resistance is obtained. When the sliding velocity increases from 0.4 to 1.6 m/s, the wear loss decreases gradually. With increasing the normal load, the wear loss increases as well. Ploughing, craters and micro-grooving are observed as dominant abrasive wear mechanisms. Whereas, when a high velocity is employed, only the oxidation mechanism controls the wear behavior of the composites.

Key words: metal matrix composite; wear mechanism; friction; hardness