Reactive-infiltration processing of SiC-metal and SiC-intermetallic composites

Abstract

Liquid-phase reactive infiltration is a rapid and net-shape method of synthesizing silicon carbide composites. We use reactive infiltration of carbon with Si–A1 and Si–Cu melts to prepare composites consisting of interpenetrating networks of β–SiC and a secondary phase assemblage containing ductile metal (A1–Si) or a metal silicide (Si–Cu). The mechanisms of phase formation have been characterized. It is shown that a rapid initial reaction upon infiltration forms a largely stationary SiC network, within which the secondary phase constitution evolves due to solute rejection and liquid phase diffusion processes. Both homogeneous composites and those with controlled composition gradients have been synthesized.