Cyclic Fatigue‐Crack Propagation in Magnesia‐Partially‐Stabilized Zirconia Ceramics

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Detail(s)

Original languageEnglish
Pages (from-to)893-903
Journal / PublicationJournal of the American Ceramic Society
Volume73
Issue number4
Publication statusPublished - Apr 1990
Externally publishedYes

Abstract

The subcritical growth of fatigue cracks under (tension‐tension) cyclic loading is demonstrated for ceramic materials, based on experiments using compact C(T) specimens of a MgO‐partially‐stabilized zirconia (PSZ), heat‐treated to vary the fracture toughness Kc from ∼3 to 16 MPa·m1/2 and tested in inert and moist environments. Analogous to behavior in metals, cyclic fatigue‐crack rates (over the range 10−11 to 10−5 m/cycle) are found to be a function of the stress‐intensity range, environment, fracture toughness, and load ratio, and to show evidence of fatigue crack closure. Unlike toughness behavior, growth rates are not dependent on through0‐thickness constraint. Under variable‐amplitude cyclic loading, crack‐growth rates show transient accelerations following low‐high block overloads and transient retardations following high‐low block overloads or single tensile overloads, again analogous to behavior commonly observed in ductile metals. Cyclic crack‐growth rates are observed at stress intensities as low as 50% of Kc, and are typically some 7 orders of magnitude faster than corresponding stress‐corrosion crack‐growth rates under sustained‐loading conditions. Possible mechanisms for cyclic crack advance in ceramic materials are examined, and the practical implications of such “ceramic fatigue” are briefly discussed. 

Research Area(s)

  • cracks, fatigue, magnesia, mechanical properties, zirconia: partially stabilized