Thermal Conductivity and Wear Resistance of A359/(SiC + Si3N4) Hybrid Composites Prepared by Squeeze Casting

Resumo

Thermal parameters and wear are considered with dry sliding for hybrid composites based on an A359 matrix prepared by squeeze casting. Composites are strengthened with addition of 5, 10, and 15 wt.% (SiC + Si₃N₄). Wear of A359/(SiC + Si₃N₄) composites proceeds under a load in the range 20 – 60 N with a sliding rate of 2.75 m/sec. It is found that A359/(SiC + Si₃N₄) composite exhibits relatively low thermal conductivity and better wear resistance than alloy A359. Friction coefficients and surface contact temperature for specimens of composite A359/(SiC + Si₃N₄) increase as there is an increase in (SiC + Si₃N₄) content within them. In studying worn surfaces it is detected that A359/(SiC + Si₃N₄) composite is covered with iron oxide that plays the role of a self-lubricating layer. The better wear resistance index for A359/(SiC + Si₃N₄) composites makes it possible to use them in the automobile industry.