Effect of the grain boundary thermal expansion coefficient on the fracture toughness in silicon nitride

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1995.tb08667.x· OSTI ID:116088

Peterson, I M; Tien, T Y ^[1]

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1. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering

The effect of thermal expansion mismatch stress between silicon nitride and different grain boundary phases on the fracture toughness of silicon nitride was investigated. Different sintering aids in the Y-Mg-Si-Al-O-N system produced silicon nitride specimens with very similar microstructures but different grain boundary phase compositions and different values of fracture toughness. The fracture toughness of the silicon nitride increased as the thermal expansion coefficient of the grain boundary phase increased. The presence of tensile residual stress at the grain boundary caused by thermal expansion mismatch between the silicon nitride and the grain boundary phase enhanced crack deflection and grain bridging.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 116088
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 9 Vol. 78; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CHEMICAL COMPOSITION
CRACK PROPAGATION
FRACTURE MECHANICS
FRACTURE PROPERTIES
GRAIN BOUNDARIES
MAGNESIUM OXIDES
MICROSTRUCTURE
POWDER METALLURGY
RESIDUAL STRESSES
SILICON NITRIDES
THERMAL EXPANSION
YTTRIUM OXIDES