International Journal of Advanced Engineering Application

Tribological Behaviour and Mechanical Characterisation of Aluminium 6061 Matrix Composites Reinforced with Silicon Carbide and Graphite Particulates Fabricated by Stir Casting

Author(s):Ranjit Kumar , Deepak Mishra

Affiliation: Department of Mechanical Engineering, Rajasthan Technical University, Kota, Rajasthan, India

Page No: 97-103

Volume issue & Publishing Year: Volume 3, Issue 5, May 2026

Journal: International Journal of Advanced Engineering Application (IJAEA)

ISSN NO: 3048-6807

DOI:

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Abstract:
Aluminium matrix composites (AMCs) have emerged as pivotal structural and tribological materials in automotive, aerospace, and industrial machinery sectors owing to their superior strength-to-weight ratio, tunable wear resistance, and improved thermal stability relative to monolithic aluminium alloys. This study investigates the tribological behaviour and mechanical properties of Al6061 matrix composites reinforced with silicon carbide (SiC) particulates at 5, 10, and 15 weight percent, and a hybrid composite incorporating 10 wt% SiC with 2 wt% graphite (Gr), all fabricated by the two-step stir casting route. Wear tests were conducted on a pin-on-disc tribometer per ASTM G99 at applied loads of 10–50 N and sliding speeds of 0.5–2.5 m/s against EN-31 steel disc at a fixed sliding distance of 1500 m. Mechanical characterisation included Vickers hardness, tensile strength, flexural strength, and impact energy measurements. Microstructural analysis was performed using optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) on both as-cast and worn surfaces. Results indicate that the Al+10%SiC composite achieves maximum hardness (89.2 HV), tensile strength (248 MPa), and wear resistance at 30 N load. The hybrid Al+10%SiC+2%Gr composite reduces coefficient of friction (COF) by 52.7% relative to the unreinforced matrix and exhibits the lowest flash temperature rise (116°C at 3 km sliding distance) owing to graphite's solid lubricant action. SEM-EDS of worn surfaces reveals a transition from abrasive to adhesive wear mechanism above 30 N in the control alloy, while reinforced composites maintain predominantly abrasive wear across the tested load range. The Archard wear model adequately predicts wear rates for loads up to 30 N (r² = 0.97), with deviations at higher loads attributed to thermal softening effects.

Keywords: aluminium matrix composite, silicon carbide, graphite, stir casting, tribology, wear rate, coefficient of friction, SEM-EDS, Archard model, hardness

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