High-temperature tensile behavior of a boron nitride-coated silicon carbide-fiber glass-ceramic composite

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1996.tb08760.x· OSTI ID:271666

Sun, E Y ^[1]; Nutt, S R ^[2]; Brennan, J J ^[3]

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1. Brown Univ., Providence, RI (United States). Div. of Engineering
2. Univ. of Southern California, Los Angeles, CA (United States). Dept. of Materials Science
3. United Technologies Research Center, East Hartford, CT (United States)

Tensile properties of a cross-ply glass-ceramic composite were investigated by conducting fracture, creep, and fatigue experiments at both room temperature and high temperatures in air. The composite consisted of a barium magnesium aluminosilicate (BMAS) glass-ceramic matrix reinforced with SiC fibers with a SiC/BN coating. The material exhibited retention of most tensile properties up to 1,200 C. Monotonic tensile fracture tests produced ultimate strengths of 230--300 MPa with failure strains of {approximately}1%, and no degradation in ultimate strength was observed at 1,100 and 1,200 C. In creep experiments at 1,100 C, nominal steady-state creep rates in the 10{sup {minus}9} s{sup {minus}1} range were established after a period of transient creep. Tensile stress rupture experiments at 1,100 and 1,200 C lasted longer than one year at stress levels above the corresponding proportional limit stresses for those temperatures. Tensile fatigue experiments were conducted in which the maximum applied stress was slightly greater than the proportional limit stress of the matrix, and, in these experiments, the composite survived 10{sup 5} cycles without fracture at temperatures up to 1,200 C. Microscopic damage mechanisms were investigated by TEM, and microstructural observations of tested samples were correlated with the mechanical response. The SiC/BN fiber coatings effectively inhibited diffusion and reaction at the interface during high-temperature testing. The BN layer also provided a weak interfacial bond that resulted in damage-tolerant fracture behavior.

• Sponsoring Organization: USDOE
• OSTI ID: 271666
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 6 Vol. 79; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
ALUMINIUM COMPOUNDS
BARIUM COMPOUNDS
BORON NITRIDES
COMPOSITE MATERIALS
CRACKS
CREEP
FATIGUE
FRACTURE PROPERTIES
GAS TURBINE ENGINES
INTERFACES
MAGNESIUM COMPOUNDS
SILICATES
SILICON CARBIDES
STRAINS
STRESSES
SURFACE COATING
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES
TRANSMISSION ELECTRON MICROSCOPY
ULTIMATE STRENGTH