The five recommendations above fall into three categories. Recommendation 1 addresses increasing the knowledge base of, and confidence in, existing CMC technology. The committee anticipates that applications for CMCs will expand if engineering designers have access to the information they need to make materials selection decisions. Thus the committee places a high priority on this recommendation.

Recommendations 2, 3, and 4 (listed in order of decreasing priority) are related to performance, which is also considered to be a high priority. Recommendation 2 is the most important in this category. The oxidation resistance of oxide fibers is attractive, but poor creep resistance is a significant limitation. Thus, Recommendation 3 addresses the need to improve this property. Recommendation 4 (regarding non-oxide fibers) is last in this category because the committee concluded that resources directed toward property improvement in fiber coatings and oxide fibers was more important. The committee is satisfied that the preliminary properties reported for Si-B-N-C amorphous fibers are sufficiently attractive to stimulate the research needed to verify them.

Recommendation 5 is last, not because cost is unimportant but because, at the current stage of the technology, performance rather than cost has limited the use of CMCs. The committee concluded that, at this time, improving properties should be of higher priority than reducing costs.