Tribological and mechanical characterization of as-cast and thermal treated Al-9Si/SiC graded composite

Abstract

Tribology and mechanical properties of thermal treated Al-9Si/10wt%SiC functionally graded composite are compared with as-cast condition. The composite was centrifugally cast as a hollow cylindrical component (Ø(outer) 100 × Ø(inner) 60 × 100 mm), characterized at three wall layers (up to 3, 10, and 18 mm) from the outer periphery. Metallographic analysis on as-cast composite and thermal treated components revealed graded structure and spheroidization of acicular Si, respectively. Elemental mapping and phase formations were confirmed through Energy-dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD) analysis. Outer layer of thermal treated component revealed maximum improvement in hardness (26%) and tensile strength (15%) compared to as-cast. Brittle mode of failure was featured through fractography. A combination of adhesive and abrasive mechanisms were predominant during reciprocating wear. EDS analysis of wear debris formed at intermediate sliding distance (1250 m) confirmed the oxide layer formation. Thus, the thermal treated composites are developed for automotive engine components vulnerable to wear.