Spark plasma sintering of graphite–aluminum powder reinforced with SiC/Si particles

• Electrical conductivity of Gr–Al powder is slightly increased by the addition of 10 wt.% SiC and 10 wt.% Si.
• No improvement in relative density and hardness of Gr–Al composite by the addition of 10 wt.% SiC and 10 wt.% Si
• Addition of 10 wt.% SiC and 10 wt.% Si improved the peak ratio of Gr–Al composite.

The growing demand for lightweight materials for a variety of engineering applications has led to increased researches on graphite and graphite aluminum composites. An attempt is made in this work to investigate the electrical conductivity of unreinforced graphite aluminum (Gr–Al) powder and graphite aluminum (Gr–Al) powder reinforced with 10 wt.% SiC and 10 wt.% Si using the spark plasma sintering techniques. In addition, a study of the microstructure and hardness of the resulting composite was done after full sintering at a pressure of 50 MPa and temperature of 550 °C. It was observed that the addition of 10 wt.% SiC and 10 wt.% Si improved the electrical conductivity of Gr–Al powder between 18.9 °C and 287 °C. The results of the composites showed that a relative density of 97.1% was achieved for Gr–Al sample sintered at 550 °C while 96.1 and 95.4% were obtained for Gr–Al 10 wt.% Si and Gr–Al 10 wt.% SiC respectively. The micro-hardness values are 26 ± 5, 26 ± 4 and 20 ± 3 HV1.0 for Gr–Al (550 °C), Gr–Al 10 wt.% Si and Gr–Al 10 wt.% SiC respectively. The peak ratio values are very much improved in the hybrid composites produced. The study has shown that hybrid Gr–Al composite is a promising material for improved peak ratio and electrical conductivity.

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