Mechanical and Thermal Properties of Silicon Carbide Composites with Chopped Si-Al-C Fiber Addition

Abstract:

The fabrication conditions of dense silicon carbide (SiC) composites containing chopped Tyranno Si-Al-C (SA) fiber were examined in this work; SiC compacts containing SA fiber (mean lengths: 214, 394 and 706 m) were hot-pressed at 1800°C for 30 min under a pressure of 31 MPa in Ar atmosphere. The fracture toughness of SiC composites with 40 mass% of SA fiber addition (sintering aid: 5 mol% Al4C3) increased from 2.8 up to 4.7 MPa•m1/2 as the fiber length increased from 214 to 706 m. The enhanced fracture toughness of the SiC composites was attributed to the lowering of fiber orientation angle (i.e., the angle between the fiber length and direction perpendicular to the hot-pressing direction) to 5° with increasing fiber length. The fracture toughness of SiC composites could be further enhanced through the incorporation of SA fibers with a carbon interface (thickness: 100 nm) into the SiC matrix. The fracture toughness of SiC composite containing 40 mass% of these fibers attained 6.0 MPa•m1/2. The thermal conductivity of SiC composites increased with fiber length from 30.5 W•m-1•K-1 to 45.5 W•m-1•K-1; with no significant influence being noted for the case of fibers with a carbon interface.

• Periodical: Key Engineering Materials (Volume 403)
• Pages: 257-260
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.403.257
• Online since: December 2008
• Authors: Kiyoshi Itatani, Ian J. Davies, Hiroshi Suemasu
• Keywords: Mechanical Property, Si-Al-C Fiber, Silicon Carbide (SiC), Thermal Property

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