Hardness, Wear and Thermal Properties of SiC/Carbon Black-Reinforced Al6061 Matrix Composites Produced via Powder Metallurgy

Abstract

In this study, carbon black (CB) obtained from the pyrolysis of waste tires was used as a reinforcement material. Al6061 alloy, widely utilized in the automotive industry, was selected as the matrix material, while silicon carbide (SiC) was employed as a secondary reinforcement. The study investigated not only the feasibility of using CB as a reinforcement material but also its compatibility with SiC. The mechanically mixed powders were compacted under a pressure of 450 MPa for 1 minute and sintered at 640°C for 360 minutes, producing the composites via the powder metallurgy (P/M) method. Microstructural images and EDS analyses revealed the presence of carbon black within the internal structure, a homogeneous distribution of the reinforcing elements, and the absence of agglomeration. Significant increases in hardness were observed with higher reinforcement content. The hybrid composite reinforced with 5% CB and 7% SiC exhibited a 101.28% increase in hardness compared to the Al6061 alloy. The most substantial reduction in wear rate, 252% relative to the Al6061 alloy, was identified in the composite reinforced with 10% CB. Furthermore, the thermal conductivity of the Al6061 alloy, initially 167 W•m⁻¹•K⁻¹, decreased to 141.5 W•m⁻¹•K⁻¹ with the addition of 7% CB. In conclusion, the addition of CB significantly improved the hardness and wear resistance of the composite while reducing its thermal conductivity.