Preparation and Mechanical Properties of SiC Whisker-Reinforced Alumina

SiC whisker reinforced alumina composites were fabricated by hot-pressing from the commercial γ-Al2O3 and SiC whisker made in Shanghai institute of Ceramics. We obtained some samples with 30vol% SiCw hot-pressed at 1800℃ in Ar atmosphere having the flexure strength of 812±38MPa and fracture toughness of 8.8±0.1MPa·m1/2 at room temperature; 560±61MPa and 6.1±0.4MPa at 1200℃ respectively. The small amount of additions accelerated densification but reduced the mechanical properties. In N2 atmosphere, SiC whisker would be injured and the composites mechanical properties degraded. Moreover, the microstructural observations indicated that the toughening mechanism of AS composites is different from whiskers pull-out and matrix's cleavage fracture at room temperature to whiskers/matrix interface debonding and matrix's intergranual fracture at high temperature.