Development of Orthogonal 3-D Woven Amorphous SiC Fiber / SiC/YSi<sub>2</sub>-Si Matrix Composites

Abstract

For evaluating Low temperature Melt Infiltration (LMI) process, adapted to amorphous SiC fiber with high toughness and low thermal stability, high-manufacturable and high-strength orthogonal 3-D woven amorphous SiC fiber / SiC / YSi2-Si Matrix Composites was developed. Thermophysical properties of candidate molten Si alloys were measured by the electrostatic levitation furnace, Si-Y alloy was selected because of the low melting temperature and superior infiltration ability compared to reference material, Si-Ti alloy. Dense orthogonal 3-D woven amorphous SiC fiber / SiC / YSi2-Si Matrix Composites of which porosity was less than 3vol.% was successfully fabricated by weaving an amorphous SiC fiber coated with CVD-BN and constructing SiC matrix via Chemical Vapor Infiltration (CVI) process and LMI. Process temperature of LMI was 50°C lower than general Melt Infiltration (MI) process with Si. It was demonstrated that the orthogonal 3-D woven amorphous SiC fiber / SiC / YSi2-Si Matrix Composites has equal tensile strength until 1100°C and excellent fatigue properties at 1100°C over 150MPa against to crystalline SiC fiber/SiC-Si Matrix Composites.