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Influencing the shape of creep cavities in nickel aluminides by stress changes

Journal Article · · Journal of Materials Research; (USA)
 [1];  [2]
  1. Institute of Physics, University of Mexico, P. O. Box 20-364, 01000 Mexico, D.F. (MX)
  2. Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6116 (US)
A nickel aluminide of composition Ni-23.5 Al-0.5Hf-0.2B (at. %) is found to develop intergranular cavities with a quasi-equilibrium shape when it is creep deformed at high temperatures and low stresses. When the temperature is lowered and the stress significantly increased (by a factor of 10), crack-like noses form at the tips of the original quasi-equilibrium cavities. Although this observation is in general agreement with previously published computer simulations, certain complications are found as well. The experimental and theoretical relationships between growth rates and sizes of the crack-like noses are inconsistent, and growth-rates vary from nose to nose. Possible reasons for these effects are discussed.
DOE Contract Number:
AC05-84OR21400
OSTI ID:
5120186
Journal Information:
Journal of Materials Research; (USA), Journal Name: Journal of Materials Research; (USA) Vol. 4:6; ISSN JMREE; ISSN 0884-2914
Country of Publication:
United States
Language:
English