Heat Treatment Effects on the Tensile Properties and Microstructures of a SiC/RBSN Composite in Nitrogen.
Abstract
The room-temperature tensile properties and constituent microstructures of a unidirectionally reinforced SiC/RBSN composite have been investigated after heat treatments at 1400, 1600, or 1800 deg C in nitrogen for up to 100 hr. The composite consisted of approx. 24 vol% of aligned 140 micrometers diameter, continuous length, chemically vapor deposited SiC fibers in a approx. 40% porous silicon nitride matrix. The composites heat treated at 1400 deg C for up to 100 hr showed elastic modulus, first matrix cracking strength, and ultimate tensile strength values similar to those of the as-fabricated composites, but those heat treated for 1 hr beyond this temperature displayed losses in all three properties. Recrystallization of the SiC fibers, reaction between the carbon-rich interface coating on the fibers and the RBSN matrix, and dissociation of the RBSN matrix are the reasons for the loss of mechanical properties. jg p2
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1995
- Accession Number
- ADA303864
Entities
People
- R. T. Bhatt
Organizations
- Glenn Research Center