Fatigue and static crack propagation in yttria-stabilized tetragonal zirconia polycrystals: Crack growth micromechanisms and precracking effects

Journal Article · Sat Nov 01 04:00:00 EST 1997 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1997.tb03192.x· OSTI ID:556420

Alcala, J; Anglada, M ^[1]

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1. Univ. Politecnica de Catalunya, Barcelona (Spain). Dept. of Materials Science and Metallurgical Engineering

The influence of precracking techniques in the crack growth behavior of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) is investigated. Load-bridge and cyclic-compression precracking enhance subsequent tensile crack growth rates, in comparison to results that are found with precracks that are extended under four-point bending prior to testing. The actual influence of these precracking techniques in the near-threshold crack growth regime is remarkably different. Although load-bridge precracking produces a pattern of crack growth fluctuations for stress intensity factors, K, lower than the effective crack-growth threshold of the material, compression-fatigue precracks start to propagate under far-field tensile loads at very fast growth rates and for K values that are slightly higher than the effective threshold. Crack-tip shielding by tetragonal-to-monoclinic transformation develops gradually, influencing the crack growth behavior in Y-TZP. Proposed fatigue crack growth micromechanisms involve damage accumulation at the crack-tip region. For K{sub max} > 3 MPa{center_dot}m{sup 1/2}, fatigue crack growth rates are strongly affected by environmental interactions at the crack tip, and postulated fatigue micromechanisms include the cyclic degradation of crack-tip shielding.

• Sponsoring Organization: Comision Interministerial de Ciencia y Tecnologia (Spain); Ministerio de Education y Ciencia (Spain)
• OSTI ID: 556420
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 11 Vol. 80; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRACK PROPAGATION
CRACKS
CRYSTAL-PHASE TRANSFORMATIONS
FATIGUE
FRACTURE MECHANICS
STRESS INTENSITY FACTORS
YTTRIUM OXIDES
ZIRCONIUM OXIDES