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An examination of the flow process in superplastic yttria-stabilized tetragonal zirconia

Journal Article · · Acta Materialia
;  [1]
  1. Univ. of Southern California, Los Angeles, CA (United States). Dept. of Materials Science and Mechanical Engineering

Extensive high temperature creep data are available for a superplastic yttria-stabilized tetragonal zirconia containing 3 mol% of Y[sub 2]O[sub 3] (termed 3Y-TZP). These data are analyzed and it is shown that, contrary to superplastic metals, intragranular slip cannot occur to accommodate grain boundary sliding at the temperatures and stresses examined experimentally. It is proposed instead that flow occurs by Coble diffusion creep controlled by movement of the Zr[sup 4+] ions and, because of the small grain sizes in the 3Y-TZP materials, the creep rates are reduced through interface-controlled diffusion creep. A detailed analysis demonstrates this approach predicts the experimental creep rates to within one order of magnitude over the range of grain sizes and temperatures examined experimentally and it accounts also for the reported values for the stress exponent and the exponent of the inverse grain size at high and low stress levels.

Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
FG03-92ER45472
OSTI ID:
6174880
Journal Information:
Acta Materialia, Journal Name: Acta Materialia Vol. 47:8; ISSN 1359-6454; ISSN ACMAFD
Country of Publication:
United States
Language:
English