Effect of flaw size on first matrix cracking stress in fiber-reinforced ceramic composites

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:96575

Kumaria, S; Singh, R N ^[1]; Bhatt, R T ^[2]

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1. Univ. of Cincinnati, OH (United States)
2. NASA-Lewis Research Center, Cleveland, OH (United States)

Influence of flaws formed during processing or while in service on the first matrix cracking stress is important in assessing and predicting the performance and reliability of a ceramic composite. In the present investigation, the effect of change in the crack length on the first matrix cracking stress of ceramic matrix composites is studied. Silicon nitride and zircon matrix composites, uniaxially reinforced with SiC fibers were fabricated along with the corresponding monolithic silicon nitride and zircon. These composites and monolithic samples were microindented to create flaws of controlled size on the surface and were then tested in 3-pt. flexure mode. The experimental results clearly indicated an evidence of flaw-size dependent non-steady state and flaw size independent steady state first matrix cracking behaviors. These observations on the first matrix cracking behaviors were compared with the theoretical predictions.

• OSTI ID: 96575
• Report Number(s): CONF-940416--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
CRACKS
MICROSTRUCTURE
SILICON CARBIDES
SILICON NITRIDES
STRESSES