Effect of graphite content on the microstructure and mechanical properties of Al5SiC-xCgr hybrid composites produced by powder metallurgy

The effect of the addition of graphite (2, 8 wt%) in aluminum and in Al5SiC composites on the microstructure and mechanical properties was investigated. The hybrid composites were fabricated through powder metallurgy technology, applying single-action compaction press (300 MPa) and free sintering (600?) in a protective nitrogen atmosphere. The addition of SiC particles to Al-xCg(r) composites reduced the weight loss in friction process. On the other hand, the addition of graphite in hybrid composites reduced the friction coefficient in relation to the matrix and the Al5SiC composites. The SEM analysis of worn surface revealed both abrasive and adhesive wear tracks.