Wear Properties of Al-Gr Composites Produced Using Liquid Homogenization Followed by spark plasma sintering (SPS)

To produce aluminum-matrix composite reinforced with graphite particles, mixing of pure aluminum and graphite powders by a new method, called homogenization in liquid phase, was used. In this procedure at first different amounts of graphite from zero to 4.5wt.% were poured into acetone, and mixed by ultrasonic. Aluminum powder was added to the solution and sonication was continued. Then the filtered mixture was dried in vacuum atmosphere at optimized temperature and time. Composite samples were produced using the mixed powder by way spark plasma sintering (SPS) under different pressure, temperature and time. The specimen microstructures were investigated by optical microscopy and scanning electron microscopy (SEM). To evaluate the mechanical properties of samples, hardness and wear tests were performed. According to the results, homogenization in liquid phase method caused significant improvement in distribution of graphite particles in the matrix and the addition of 3wt.% graphite in the matrix was gained. Improved mechanical properties were obtained at 3wt.% graphite. According to the results, SPS process decreased the wear rate of Al-3wt.% Gr composite up to 55%, compared to the pure aluminum.