Hostname: page-component-848d4c4894-xfwgj Total loading time: 0 Render date: 2024-06-17T15:17:21.086Z Has data issue: false hasContentIssue false

Point Defects and High-Temperature Deformation of NiO

Published online by Cambridge University Press:  28 February 2011

K. C. Goretta
Affiliation:
Work performed under a laboratory graduate participantship at Argonne National Laboratory. Program administered by the Argonne Division of Education Programs with funding from the U.S. Department of Energy.
J. L. Routbort
Affiliation:
Materials Science and Technology Division, Argonne National Laboratory, Argonne, IL 60439
Get access

Abstract

The steady-state flow stress τs in nonstoichiometric NiO single crystals has been measured in the temperature range of 1428 to 1653 K with oxygen partial pressures p(O2) between 6 and 1×105 Pa. Strain rates were varied from 1×10−5 to 2×10−3 s−1. Transmission electron microscopy indicates that dislocation climb is the primary mechanism of recovery. Because dislocation climb is diffusion controlled, the data may be described at fixed temperature by = Aτns (O2)1/m, where n is the stress exponent and m is a parameter that is determined by the dominant atomic defects on each sublattice. At high temperatures and p(O2) > 2×104 Pa, n was found to be in agreement with dislocation-climb models; however, n increased at low p(O2) owing to effects of impurities. The values of m are consistent with control of climb rate by diffusion of singly charged oxygen vacancies for low p(O2) and by diffusion of neutral oxygen interstitials for high p(O2). At lower temperatures, the values of n are strongly affected by dislocation/impurity interactions for all p(O2).

Type
Research Article
Copyright
Copyright © Materials Research Society 1986

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

1. Ilschner, B. et al., Disc. Faraday Soc. 38, 243 (1964).CrossRefGoogle Scholar
2. Reppich, B., Phys. Stat. Sol. 20, 69 (1967).CrossRefGoogle Scholar
3. Clauer, A. H. et al., J. Mater. Sci. 6, 1379 (1971).CrossRefGoogle Scholar
4. Routbort, J. L., Acta Metall. 30, 663 (1982).CrossRefGoogle Scholar
5. Dominguez-Rodriguez, A. et al., Phil. Mag. A46, 411 (1982).CrossRefGoogle Scholar
6. Cabrera-Caño, J. et al., Phil. Mag. A46, 397 (1982).CrossRefGoogle Scholar
7. Cabrera-Caño, J. et al, Res. Mechanica 1, 289 (1980).Google Scholar
8. Routbort, J. L. in: Defect Properties and Processing of High-Technology Nonmetallic Materials, Crawford, J. H., Chen, Y., Sibley, W. A., eds. (North-Holland, New York 1984) pp. 9399.Google Scholar
9. Castaing, J. et al. in: Deformation of Ceramic Materials II, Tressler, R. E., Bradt, R. C., eds. (Plenum Press, New York 1984) pp. 141158.CrossRefGoogle Scholar
10. Cannon, W. R. and Langdon, T. G., J. Mater. Sci. 18, 1 (1983).CrossRefGoogle Scholar
11. Kofstad, P., Nonstoichiometry, Diffusion, and Electrical Conductivity in Binary Metal Oxides (Wiley Interscience, New York 1972) pp. 213257.Google Scholar
12. Routbort, J. L. and Goretta, K. C., to be published.Google Scholar
13. Goretta, K. C. et al., Scripta Metall. 19, 1361 (1985).CrossRefGoogle Scholar
14. Peterson, N. L. and Wiley, C. L., J. Phys. Chem. Solids 46, 43 (1985).CrossRefGoogle Scholar
15. Goretta, K. C. et al., J. Mater. Sci. Lett., in press.Google Scholar
16. Dominguez-Rodriguez, A. et al., Phys. Stat. Sol. (a) 85, 445 (1984).CrossRefGoogle Scholar
17. Dominguez-Rodriguez, A. and Castaing, J., Scripta Metall. 9, 551 (1975).CrossRefGoogle Scholar