Mechanical Properties of MoSi₂ Matrix Sintered Composites at Elevated Temperature

Abstract

SiC whisker reinforced MoSi₂ composites were fabricated by hot pressing to more than 98% of theoretical density. Flexural strength and steady state creep strain rate of these composites exhibited substantial improvements over MoSi₂ matrix material. In the case of the MoSi₂-20vol% SiC whisker composites, the flexural strength was 1010 MPa (2.8 times MoSi2 matrix) at room temperature and 1420 MPa (3.7 times MoSi₂ matrix) at 1000°C; the steady state creep strain rate under a stress of 100 MPa at 1300°C was 2.2×10_-7/Sec (1/26 of MoSi₂ matrix). The material and microstructural characteristics contributing to these improvement mechanisms are discussed in this paper.