Dispersoid-Toughened Silicon Nitride Composites
Abstract
This report is a summary of results of a study aimed at the development of silicon nitride composites of enhanced fracture toughness and strength utilizing particulate and whisker dispersoids. Composites with 40% higher fracture toughness and 25% higher room-temperature fracture strength over that of the base silicon nitride "monolith", have been prepared using, 30 v/o SiC whisker dispersoids. An increase in fracture toughness of 70% has been observed at 35 v/o whisker additions. Both fracture toughness and strength improvements persist over a wide range of temperatures (25-1200 deg C). These, composites exhibit excellent oxidation resistance and improved resistance to slow crack growth and creep at elevated temperatures. A process for fabrication of complex composite ceramic parts was developed and demonstrated. The present study has also provided extensive information regarding microstructure-property dependence in dispersoid-modified ceramics, which has been utilized to derive a formal theory of fracture toughness and microstructure relationship.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1988
- Accession Number
- ADA351520
Entities
People
- G. Zilberstein
- J. G. Baldoni
- J. Neil
- S. T. Buljan