Influence of Fiber Surface Structure on Interfacial Structure between Fiber and Matrix in Vapor Grown Carbon Fiber Reinforced Aluminum Matrix Composites

Abstract

Vapor grown carbon fiber reinforced pure aluminum matrix composites were fabricated by the hot-pressing method below the melting temperature of pure aluminum. The surface structures of the vapor grown carbon fibers and the interfacial structures between the fibers and the matrix in the composite were observed. The precipitation mechanism of crystalline aluminum carbide was also investigated. An interlayer with an amorphous-like structure formed at the interface between the carbon surface structure and the aluminum matrix. This interlayer between the wave or irregular carbon structure and the matrix grew more rapidly than that formed between the linear carbon surface structure and the matrix. The thickness of the interlayer increased with the increased fabrication temperature of the composite. Crystalline aluminum carbide could not easily be precipitated in the composite fabricated below 933 K owing to the thicker interlayer separating the vapor grown carbon fibers and aluminum. By either extending the heat-treatment time to 18 ks or increasing the fabrication temperature to 933 K, we could promote the precipitation of crystalline aluminum carbide in the composite. After heat-treating the composite produced at 933 K, aluminum carbide crystals precipitated from the stacked carbon lamellae at the interface between the fibers and the matrix.