Mechanical Properties of β-SiAlON Composites with Crystalized Grain Boundary

Abstract

Bending strength and fracture toughness of β-SiA1ON composites were measured before and after heat-treatment. Bending strength at room and high temperatures innereased after heat-treatment. However, fracture toughness and microstructure were not changeed by heattreatment. There was a peak at 1323K in high temperature internal friction for samples before heat-treatment, but the peak was disappeared by heat-treatment. New crystalline phases such as (Y, Yb)₂Si₂O₇ and (Y, Yb)₄Al₂O₉ were observed by crystallization of the grain boundary after heat-treatment.