Aluminium–Silicon Carbide (Al–SiC) metal matrix composites (MMCs) have attracted considerable industrial interest owing to their superior specific strength, stiffness, and wear resistance relative to unreinforced aluminium alloys, making them particularly attractive for weight-sensitive automotive structural components including suspension arms, brake rotors, and engine mounts. However, the fatigue life and tribological behaviour of Al–SiC MMCs fabricated by stir casting — a commercially scalable and cost-effective processing route — remain insufficiently characterised under multi-axial loading and elevated temperature conditions representative of in-service automotive environments. This study fabricates Al 6061 alloy reinforced with SiC particulates at 5 wt%, 10 wt%, 15 wt%, and 20 wt% via double-pass stir casting at 750°C with electromagnetic stirring and characterises the resulting composites through tensile testing, rotating-bending fatigue testing (R = –1, 10⁶ to 10⁸ cycle range), pin-on-disc tribological assessment under dry and lubricated conditions, and fractographic analysis by SEM. The effect of SiC reinforcement fraction on S–N fatigue behaviour, wear rate, coefficient of friction, and failure mode is systematically quantified. Results confirm that 15 wt% SiC addition yields the optimal fatigue endurance limit (172 MPa, 38% above unreinforced control at 10⁷ cycles) while maintaining acceptable ductility (elongation 4.2%). The 20 wt% SiC composite exhibits the lowest specific wear rate (2.4 × 10⁻⁵ mm³/N·m) under dry sliding, representing a 61% reduction versus the matrix alloy. SEM fractography reveals a transition from transgranular fatigue cracking in low-SiC composites to interfacial debonding-dominated fracture at 20 wt% SiC, with implications for optimum reinforcement content selection in fatigue-critical designs.
Rajesh K. Srivastava (Sun,) studied this question.