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

Abstract

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 10wt.% SiC and 10wt.% 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 50MPa and temperature of 550°C. It was observed that the addition of 10wt.% SiC and 10wt.% 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 10wt.% Si and Gr–Al 10wt.% SiC respectively. The micro-hardness values are 26±5, 26±4 and 20±3HV1.0 for Gr–Al (550°C), Gr–Al 10wt.% Si and Gr–Al 10wt.% 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.