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Does a threshold stress for creep exist in HfC-dispersed NiAl?Recently it was proposed (Jha et al., 1989; Whittenberger et al., 1990) on the basis of constant velocity testing at 1300 K that dispersion strengthened NiAl composites containing about 4 wt pct HfC possess threshold stresses for creep. Further, 1300 K compression testing has been conducted on NiAl+4HfC, and diametrically opposite behavior has been found: for constant load creep tests a normal power law behavior was observed. However, additional constant velocity testing still indicates that the flow stress is essentially independent of strain rate below 10 exp -6/s. Examination of NiAl+4.3HfC specimens deformed under constant velocity conditions revealed that the original hot extruded small grain structure could be converted to large, elongated grains during testing. Such a transformation appears to be responsible for the apparent threshold stress behavior in HfC dispersed NiAl.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Whittenberger, J. D.
(NASA Lewis Research Center Cleveland, OH, United States)
Ray, Ranjan
(Marko Materials, Inc. Billerica, MA, United States)
Jha, Sunil C.
(Texas Instruments, Inc. Attleboro, MA, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1991
Subject Category
Metallic Materials
Meeting Information
Meeting: MRS Symposium
Location: Boston, MA
Country: United States
Start Date: November 27, 1990
End Date: November 30, 1990
Accession Number
Distribution Limits

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