Mechanical and Thermal Properties of Vapor-Grown Carbon Fiber Reinforced Aluminum Matrix Composites by Plasma Sintering

Abstract

Vapor-grown carbon fiber (VGCF) reinforced aluminum matrix composites were fabricated by plasma sintering method, and their mechanical and thermal properties were investigated. The aluminum powders with average diameters of 1 μm, 3 μm and 30 μm were chosen as the matrix. The monolithic aluminum blocks were also fabricated by plasma sintering method in order to comparing with the composites. As decreasing the aluminum powder size, VGCFs became to disperse more uniformly in composites. Compared with the monolithic aluminum block, Vickers hardness of the composites was enhanced remarkably. For 1 μm aluminum powders, the increment rate of Vickers hardness of the composites to monolithic aluminum was as high as 78.3%. While the tensile strength of the composites was lower than that of the monolithic aluminum. In contrast, the coefficient of thermal expansion of composites with 1 μm or 3 μm and 30 μm aluminum powders were decreased and increased, respectively, compared with the aluminium blocks with their powder. The thermal conductivity of the composites also increased compared with that of the monolithic aluminum blocks, but was not dependent on the size of aluminum powders.