Microstructure and mechanical properties of SiC based composites with dispersed B4C particles
Nakahira Atsushi; Yoshida Tsuyoshi; Kijima Kazunori
Abstract:The effect of micronsize B4C dispersion on the sintering behavior of SiC was investigated for SiC/B4C composites prepared by hot pressing method. By use of 4wt% carbon and 1wt% boron as sintering additives, nearly fully dense SiC/B4C composites were hot pressed in an argon atmosphere at 2150 deg. for 1h of holding time. The effects of B4C dispersion on the grain size and microstructure of SiC/B4C composite were also studied by SEM and TEM. The incorporation of micronsize B4C into SiC matrix inhibited the sinterability of SiC up to the addition of 10vol% B4C for SiC/B4C composites hot pressed at 2200 deg.. However, in the case of adding 20% B4C, the microstructure consisted of relatively large SiC matrix grains and their morphology was relatively round. Some mechanical properties, Vickers hardness and fracture toughness, were evaluated for the hot pressed SiC/B4C composites. The relation between microstructure and mechanical properties was investigated for SiC/B4C composites. Key Words:SiC, B4C, composite, microstructures, hot-pressing method, grain size, mechanical properties, hardness, fracture toughness