An investigation of the effects of secondary processing on the fracture properties of a SiCp-6XXX Al composite

Abstract

Discontinuous reinforced aluminum (DRA) composites are attractive as structural materials because of their desirable stiffness and strength to weight ratios and relative ease of manufacture. However, they typically display low tensile ductility and fracture toughness. In this work, the impact of post- fabrication deformation processing and heat treatment on the fracture properties of a 17.5 vol. % SiCsubp reinforced Al 6092 matrix composite is investigated. Process temperature, total strain and strain rate during extrusion were varied in order to explore the feasibility of obtaining Particle Stimulated Nucleation (PSN) of recrystallization during processing, with the goal of refining the matrix grain size. Additionally, various combinations of solution and aging treatments were investigated with the aim of obtaining a number of stable matrix microstructural conditions with varying levels of composite strength and fracture toughness. A preliminary investigation of fracture mechanisms and their dependence on the matrix aging state has also been carried out using optical and scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), and is reported here.