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Title: Time-dependent strength degradation of a siliconized silicon carbide determined by dynamic fatigue

Abstract

Both fast-fracture strength and strength as a function of stressing rate at room temperature, 1,100, and 1,400 C were measured for a siliconized SiC. The fast-fracture strength increased slightly from 386 MPa at room temperature to 424 MPa at 1,100 C and then dropped to 308 MPa at 1,400 C. The Weibull moduli at room temperature and 1,100 were 10.8 and 7.8, respectively, whereas, at 1,400 C, the Weibull modulus was 2.8. The very low Weibull modulus at 1,400 C was due to the existence of two exclusive flaw populations with very different characteristic strengths. The data were reanalyzed using two exclusive flaw populations. The ceramic showed no slow crack growth (SCG), as measured by dynamic fatigue at 1,100 C, but, at 1,400 C, an SCG parameter, n, of 15.5 was measured. Fractography showed SCG zones consisting of cracks grown out from silicon-rich areas. Time-to-failure predictions at given levels of failure probabilities were performed.

Authors:
 [1]
  1. Oak Ridge National Lab., TN (United States). High Temperature Materials Lab.
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
131534
DOE Contract Number:  
AC05-84OR21400
Resource Type:
Journal Article
Journal Name:
Journal of the American Ceramic Society
Additional Journal Information:
Journal Volume: 78; Journal Issue: 10; Other Information: PBD: Oct 1995
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 20 FOSSIL-FUELED POWER PLANTS; COMPOSITE MATERIALS; MECHANICAL PROPERTIES; SILICON CARBIDES; SILICON; FOSSIL-FUEL POWER PLANTS; HEAT EXCHANGERS; FRACTURE PROPERTIES; FATIGUE; CRACKS; FRACTOGRAPHY; CRACK PROPAGATION; POROSITY; TEMPERATURE DEPENDENCE; FLEXURAL STRENGTH

Citation Formats

Breder, K. Time-dependent strength degradation of a siliconized silicon carbide determined by dynamic fatigue. United States: N. p., 1995. Web. doi:10.1111/j.1151-2916.1995.tb08040.x.
Breder, K. Time-dependent strength degradation of a siliconized silicon carbide determined by dynamic fatigue. United States. https://doi.org/10.1111/j.1151-2916.1995.tb08040.x
Breder, K. Sun . "Time-dependent strength degradation of a siliconized silicon carbide determined by dynamic fatigue". United States. https://doi.org/10.1111/j.1151-2916.1995.tb08040.x.
@article{osti_131534,
title = {Time-dependent strength degradation of a siliconized silicon carbide determined by dynamic fatigue},
author = {Breder, K},
abstractNote = {Both fast-fracture strength and strength as a function of stressing rate at room temperature, 1,100, and 1,400 C were measured for a siliconized SiC. The fast-fracture strength increased slightly from 386 MPa at room temperature to 424 MPa at 1,100 C and then dropped to 308 MPa at 1,400 C. The Weibull moduli at room temperature and 1,100 were 10.8 and 7.8, respectively, whereas, at 1,400 C, the Weibull modulus was 2.8. The very low Weibull modulus at 1,400 C was due to the existence of two exclusive flaw populations with very different characteristic strengths. The data were reanalyzed using two exclusive flaw populations. The ceramic showed no slow crack growth (SCG), as measured by dynamic fatigue at 1,100 C, but, at 1,400 C, an SCG parameter, n, of 15.5 was measured. Fractography showed SCG zones consisting of cracks grown out from silicon-rich areas. Time-to-failure predictions at given levels of failure probabilities were performed.},
doi = {10.1111/j.1151-2916.1995.tb08040.x},
url = {https://www.osti.gov/biblio/131534}, journal = {Journal of the American Ceramic Society},
number = 10,
volume = 78,
place = {United States},
year = {1995},
month = {10}
}