Hostname: page-component-7479d7b7d-qlrfm Total loading time: 0 Render date: 2024-07-12T16:17:10.007Z Has data issue: false hasContentIssue false
  • English
  • Français

Defect structures in cold worked and small grain pure and boron-doped Ni3Al alloys

Published online by Cambridge University Press:  31 January 2011

S. G. Usmar  and
K. G. Lynn
S. G. Usmar
Affiliation:
Department of Applied Science, Brookhaven National Laboratory, Upton, New York 11973
K. G. Lynn
Affiliation:
Department of Applied Science, Brookhaven National Laboratory, Upton, New York 11973
Get access

Abstract

Positron lifetime spectroscopy was used to study the isochronal annealing of cold worked Ni3Al samples. In pure Ni76Al24, Ni74Al26, and boron-doped Ni74Al26 three annealing stages were observed. Boron-doped Ni76Al24 showed only two annealing stages. Vacancy annealing (stage III) was identified in all cases to start at ∼250 °C, somewhat higher than previously reported. The discrepancy is suggested to be due to carbon-vacancy interactions, because carbon (impurities) was observed to diffuse out of all samples at or above ∼350 °C. The high-temperature annealing stage in boron-doped Ni76Al24 (which is ductile) starts at 700–750 °C and is complete at 1000 °C. This stage was attributed to migration of dislocations to various sinks. In pure Ni76Al24, Ni74Al26, and boron-doped Ni74Al26 (which are brittle) the intermediate and high-temperature annealing stages occur at ∼750–800 and 1000 °C, respectively. These stages were attributed to the migration of dislocations (750–800 °C) and recrystallization (∼1000 °C) with incomplete annealing of dislocations at 1000 °C. This being the case, it is clear that dislocations interact with grain boundaries far more strongly in brittle than in ductile Ni3Al alloys. Thus, these data strongly suggest that the ductilization of Ni76Al24 by boron is largely due to a change in grain boundary structure which inhibits the pinning of dislocations at grain boundaries that occurs in pure Ni76Al24 (i.e., boron increases the susceptibility of grain boundaries to slip). Similar results for small-grain samples support this interpretation.

Type
Articles
Information
Journal of Materials Research , Volume 4 , Issue 1 , February 1989 , pp. 55 - 61
Copyright
Copyright © Materials Research Society 1989

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

1Aoki, K. and Izumi, O., Nippon Kingku Takkaishi 43, 1190 (1979).Google Scholar
2Liu, C.T., White, C.L., and Horton, J. A., Acta Metall. 33, 213 (1985).CrossRefGoogle Scholar
3White, C.L., Padgett, R.A., Liu, C.T., and Yalisove, S.M., Scripta Metall. 18, 1417 (1984).CrossRefGoogle Scholar
4Horton, J.A. and Miller, M.K., Mater. Res. Soc. Symp. Proc. 81, 105 (1987).CrossRefGoogle Scholar
5Miller, M. K. and Horton, J. A., Scripta Metall. 20, 789 (1986).CrossRefGoogle Scholar
6Takasugi, T. and Izumi, O., Acta Metall. 33, 1247 (1985).CrossRefGoogle Scholar
7Takasugi, T., Izumi, O., and Masahashi, N., Acta Metall. 33, 1259 (1985).Google Scholar
8Schulson, E. M., Weiks, T. P., Baker, I., Frost, H. J., and Horton, J. A., Acta Metall. 34, 1395 (1986).CrossRefGoogle Scholar
9Chen, S.P., Voter, A. F., and Srolovitz, J., Proc. Mater. Res. Soc. Symposium, Vol. 81, p. 45, 1987.CrossRefGoogle Scholar
10Foiles, S. M., Proc. Mater. Res. Soc. Symposium, Vol. 81, p. 51, 1987.CrossRefGoogle Scholar
11Bond, G. M., Robertson, I. M., and Birnbaum, H. K., J. Mater. Res. 2, 436 (1987).CrossRefGoogle Scholar
12For background and reviews the reader is referred to West, R. N., Positron Studies of Condensed Matter, Taylor Francis, London, 1974; R. N. West, in Topics in Current Physics: Positrons in Solids, edited by P. Hautojavri (Springer-Verlag, New York, 1979), p. 89; Positron Solid-Slate Physics, edited by W. Brandt and A. Dupasquier (North Holland, New York, 1983); W. Triftshauser, in Topics in Current Physics: Microscopic Methods in Metals, edited by V. Gonser (Springer-Verlag, 1986), p. 249.Google Scholar
13Hardy, W.H. II, and Lynn, K.G., IEEE Trans. Nucl. Sci. 23NS, 229 (1976).CrossRefGoogle Scholar
14Usmar, S.G. and Lynn, K.G., Mater. Res. Soc. Symp. Proc. 81, 111 (1987).CrossRefGoogle Scholar
15Virtue, C. J., Douglas, R. J., and B.T. A. McKee, Comp. Phys. Commun. 15, 97 (1978).CrossRefGoogle Scholar
16Kirkegaard, P. and Eldrup, M., Comp. Phys. Commun. 7, 401 (1974).Google Scholar
17Hall, T. M., Goland, A.N., and Snead, C.L., Phys. Rev. B1O, 3062 (1974).Google Scholar
18Wang, T. M., Shimotomai, M., and Doyama, M., J. Phys. F: Metal Phys. 14, 37 (1984).CrossRefGoogle Scholar
19Doyama, M. and Cotterill, R. M. J., Proc. 5th Intern. Conf. Positron Annihilation, edited by Hasiguti, R. R. and Fujiwara, K. (The Japan Inst. of Metals, Sendai, 1979), p. 89.Google Scholar
20Smedskjaer, L. C., Manninen, M., and Fluss, M. J., J. Phys. F 10, 2237 (1980).CrossRefGoogle Scholar
21Park, Yonk-Ki, Waber, James T., Meshii, Michael, Snead, C. L. Jr., and Park, C. G., Phys. Rev. B34, 823 (1986).CrossRefGoogle Scholar
22Bergersen, P. and Stott, M. J., Solid State Commun. 7, 1203 (1969).CrossRefGoogle Scholar
23Connors, P.C. and West, R.N., Phys. Letts. A30, 245 (1969).Google Scholar
24Sieloff, D. D., Brenner, S. S., and Burke, M. G., Mater. Res. Soc. Symp. 81, 87 (1987).Google Scholar
25Liu, C. T., White, C. L., and Horton, J. A., Acta Metall. 33, 213 (1985).Google Scholar
26King, A. H. and Yoo, M.H., Proc. Mater. Res. Soc. Symp., Vol. 81, p. 99, 1987.CrossRefGoogle Scholar