Hostname: page-component-77c89778f8-fv566 Total loading time: 0 Render date: 2024-07-19T17:34:39.057Z Has data issue: false hasContentIssue false
  • English
  • Français

Does A Threshold Stress For Creep Exist in Hfc-Dispersed Nial?

Published online by Cambridge University Press:  26 February 2011

J. Daniel Whittenberger ,
Ranjan Ray  and
Sunil C. Jha
J. Daniel Whittenberger
Affiliation:
NASA Lewis Research Center, Cleveland, OH 44135
Ranjan Ray
Affiliation:
Marko Materials, Inc.N. Billerica, MA 01862
Sunil C. Jha
Affiliation:
Texas Instruments, Attleboro, MA, 02703
Get access

Abstract

Recently it was proposed [S.C. Jha, et al., Mater. Sci. & Eng. A119 (1989) 103 & J.D. Whittenberger, et al., J. Mat. Sci. 25, (1990) 2771] 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 normal power law behavior was observed (strain rate proportional to the stress raised to the power n); however additional constant velocity testing still indicates that the flow stress is essentially independent of strain rate below 10−6 s−1. Examination of NiAl+4.3HfC specimens after being 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.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 213: Symposium Q – High-Temperature Ordered Intermetallic Alloys IV , 1990 , 581
Copyright
Copyright © Materials Research Society 1991

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Whittenberger, J.D.: J. Mat. Sci. 22, (1987) 394.Google Scholar
2. Jha, S.C., Ray, R. and Clemm, P.: “Fine Grain Nickel-Aluminide Alloy with Improved Toughness Made via Rapid Solidification Technology” Final report for contract NAS3–25132, July 1987.Google Scholar
3. Jha, S.C. and Ray, R.: J. Mat. Sci. Lett. 7 (1988) 285.Google Scholar
4. Jha, S.C., Ray, R. and Gaydosh, D.J.: Scr. Metall. 23 (1989) 805.Google Scholar
5. Jha, S.C., Ray, R. and Whittenberger, J.D.: Mat. Sci. Eng. A ll9 (1989) 103.Google Scholar
6. Whittenberger, J.D., Gaydosh, D.J and Kumar, K.S.: J. Mat. Sci. 25, (1990) 2771.CrossRefGoogle Scholar
7. Whittenberger, J.D.: J. Mat. Sci. 23, (1988) 235.Google Scholar
8. Whittenberger, J.D: Properties of Oxide Dispersion Strengthened Alloys, New Materials by Mechanical Alloying Techniques. eds. Arzt, E. and Schultz, L., Deutsche Gesellschaft für Metallkunde, 1989, pp. 200–215.Google Scholar