Effect of sintering techniques on microstructural, mechanical and tribological properties of Al-SiC composites

In this paper, the effects of sintering techniques (conventional, CS and electric resistance, ERS) and SiC content (1, 3 and 5 wt. %) on the microstructural, mechanical and tribological properties were investigated. Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were performed for microstructural investigation. Density, porosity and hardness were evaluated at different weight fractions of SiC for comparative study. Tribological behaviour was evaluated in terms of wear loss and coefficient of friction (COF). Worn-out surfaces and formed debris were also studied using SEM for understanding the wear mechanism. Results indicated that addition of SiC improved the hardness, wear resistance and COF. With addition of 5 wt. % SiC the hardness improved by 32 % for CS and 30% for ERS, wear resistance improved by 37 % for CS and 40% for ERS while COF improved by 3 % for CS (3 wt.% SiC) and 6 % for ERS (5 wt.% SiC) compared to neat Al. ERS processed composites resulted in better densification, improved hardness (12-14%) and tribological behaviour (wear resistance 36-39 % and COF 7-15 %) for 1-5 wt. % SiC compared to CS processed ones. Abrasion, adhesion and delamination were the controlling wear mechanism for Al-SiC composites with lesser adhesion wear in ERS composites.