Surface cracking in layers under biaxial, residual compressive stress

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.tb08668.x· OSTI ID:116089

Ho, S; Hillman, C; Lange, F F; Suo, Z ^[1]

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1. Univ. of California, Santa Barbara, CA (United States). Materials Dept.

Thin two-phase, Al{sub 2}O{sub 3}/t-Zr(3Y)O{sub 2} layers bounded by much thicker Zr(3Y)O{sub 2} layers were fabricated by co-sintering powders. After cooling, cracks were observed along the center of the two-phase, Al{sub 2}O{sub 3}/t-Zr(3Y)O{sub 2} layers. Although the Al{sub 2}O{sub 3}/t-Zr(3Y)O{sub 2} layers are under residual, biaxial compression far from the surface, tensile stresses, normal to the center line, exist at and near the surface. These highly localized tensile stresses can cause cracks to extend parallel to the layer, to a depth proportional to the layer thickness. A tunneling/edge cracking energy release rate function is developed for these cracks. It shows that for a given residual stress, crack extension will take place only when the layer thickness is greater than a critical value. A value of the critical thickness is computed and compared with an available experimental datum point. In addition, the behavior of the energy release rate function due to elastic mismatch is calculated via the finite element method (FEM). It is also shown how this solution for crack extension can be applied to explain cracking associated with other phenomena, e.g., joining, reaction couples, etc.

• Sponsoring Organization: USDOE
• OSTI ID: 116089
• 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
CRACK PROPAGATION
CRACKS
FINITE ELEMENT METHOD
FRACTURE MECHANICS
FRACTURE PROPERTIES
LAYERS
MATHEMATICAL MODELS
RESIDUAL STRESSES
SINTERING
STRESSES
YTTRIUM OXIDES
ZIRCONIUM OXIDES