Crack shielding in Ce-TZP/Al{sub 2}O{sub 3} composites: Comparison of fatigue and sustained crack growth specimens

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb06963.x· OSTI ID:142240

Tsai, Jingfong; Belnap, J D; Shetty, D K ^[1]

---

1. Univ. of Utah, Salt Lake City, UT (United States). Dept. of Materials Science and Engineering

Crack shielding stress intensities in in situ loaded compact tension specimens of two types of ceria-partially-stabilized zirconia/alumina (Ce-TZP-Al{sub 2}O{sub 3}) composites with prior histories of subcritical crack growth in sustained and tension-tension fatigue loading were directly assessed using laser Raman spectroscopy. Crack-tip stress fields within the transformation zones were measured by measuring a stress-induced frequency shift of a peak corresponding to the tetragonal phase. The peak shift as a function of the applied stress was separately calibrated using a ball-on ring flexure test. Total crack shielding stress intensity was estimated from the far-field applied stress intensity and the local crack-tip stress intensity assessed from the measured near-crack-tip stresses. The shielding stress intensities were consistently lower in the fatigue specimens than in the sustained load crack growth specimens. The reduced crack shielding developed in the fatigue specimens was independently confirmed by measurements of larger crack-opening displacement under far-field applied load as compared to the sustained load crack growth specimens. Thus, diminished crack shielding was a major factor contributing to the higher subcritical crack growth rates exhibited by the Ce-TZPAl{sub 2}O{sub 3} composites in tension-tension cyclic fatigue.

• Sponsoring Organization: USDOE
• OSTI ID: 142240
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 1 Vol. 77; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CERIUM OXIDES
COMPOSITE MATERIALS
CRACKS
CRYSTAL-PHASE TRANSFORMATIONS
EXPERIMENTAL DATA
MECHANICAL PROPERTIES
ZIRCONIUM OXIDES