Investigation of Interfacial Shear Strength in SiC/Si3N4 Composites
Abstract
A fiber push-out technique was used to determine fiber/matrix interfacial shear strength (ISS) for silicon carbide fiber reinforced reaction- bonded silicon nitride (SiC/RBSN) composites in the as-fabricated condition and after consolidation by hot isostatic pressing (HIPing). In situ video microscopy and acoustic emission detection greatly aided the interpretation of push-out load/displacement curves. The as-fabricated and HIPed SiC/RBSN composites showed very different fiber push-out behavior as reflected by differently shaped load/ displacement curves. The push-out data revealed the presence of definite, but weak, fiber/matrix bonding in both the as-fabricated composite and a composite HIPed at low temperature and showed the absence of fiber/matrix bonding in a composite HIPed at high temperature. The HIPed composites exhibited significantly higher frictional interfacial shear stresses as well as evidence of interfacial wear during fiber sliding. Finally, fiber push-out testing of different thickness samples revealed two regimes of fiber/matrix debonding behavior. For thinner samples, a single complete debonding event occurs; whereas, for thicker samples, a debond initiation of a critical length occurs and is followed by stable debond propagation with increasing applied load.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1991
- Accession Number
- ADA239502
Entities
People
- J. D. Kiser
- J. I. Eldridge
- Ramakrishna T. Bhatt
Organizations
- National Aeronautics and Space Administration