Processing and Properties of Oxide Fiber Reinforced Alumina Composites

Abstract

A simple, low-cost processing method involving slurry infiltration, hot pressing and subsequent densification was developed to manufacture NextelTM 440fiber reinforced alumina (N440/A) composites. The influence of alumina sol on the densification of alumina matrix was investigated through XRD and SEM. Results showed that the introduction of alumina sol into slurry promoted the densification of alumina matrix. Then the effect of sintering temperature from 1100°C to 1300°C on mechanical properties of N440/A composites was investigated. The optimized composite material exhibited a tensile strength > 140MPa and flexural strength > 170MPa.The analysis of the fracture surface suggested that the porous matrix played a vital role in the toughening mechanism of N440/A composites. Numerous matrices attach to pullout fibers of N440/A composites, indicating that matrix cracks propagate through micro-pores in the matrix and deflect at the fiber/matrix interface effectively.