Accession Number:

ADA063569

Title:

High-Temperature Mechanical Properties of Sintered Alpha Silicon Carbide (13 October 1977 - 13 October 1978),

Descriptive Note:

Corporate Author:

AIRESEARCH MFG CO OF CALIFORNIA TORRANCE

Personal Author(s):

Report Date:

1978-12-18

Pagination or Media Count:

58.0

Abstract:

This report summarizes the results of the third year of a continuing research program on the various grades of silicon carbide of interest for naval applications. This program has thus been designated as ONR-3. The ONR-3 program was initiated to further explore the limitations of SASC in oxidizing and marine salt-bearing environments as a function of reliability particularly for use in high temperature heat exchangers and turbines. The program was also formulated to generate stressed-lifetime data using differential strain rate techniques. These data can be generated by stress rupture testing, but it is a time consuming procedure. If there is little or no crack growth for the particular testing environment during stress rupture testing, the time to failure is either very long or occurs within a very narrow stress interval. To minimize the need to collect stress rupture data, the same information can be generated from other types of tests. This approach is based on the fracture mechanics theory that fatigue failure of ceramics occurs from stress-dependent growth of preexisting flaws to dimensions critical for spontaneous crack propagation. Furthermore, using expressions developed for time-to-failure predictions, the life expectancy of parts under a particular cyclic loading schedule can be predicted from static stress rupture or dynamic testing experiments.

Subject Categories:

  • Ceramics, Refractories and Glass

Distribution Statement:

APPROVED FOR PUBLIC RELEASE