Hostname: page-component-848d4c4894-8kt4b Total loading time: 0 Render date: 2024-06-25T02:37:15.010Z Has data issue: false hasContentIssue false
  • English
  • Français

Evolution of the two-phase microstructure L12 + DO22 in near-eutectoid Ni3(Al,V) alloy

Published online by Cambridge University Press:  03 March 2011

L.A. Bendersky ,
F.S. Biancaniello  and
M.E. Williams
L.A. Bendersky
Affiliation:
Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
F.S. Biancaniello
Affiliation:
Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
M.E. Williams
Affiliation:
Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
Get access

Abstract

Transmission electron microscopy and powder x-ray diffraction methods have been used to investigate the evolution of two-phase (L12 + DO22) microstructures from the quenched fcc phase of the Ni-5Al-20V (at. %) alloy. The microstructure after annealing in a temperature range from 650 to 900 °C differs from the eutectoid structure which might be expected for the alloy according to the eutectoid-type phase diagram of the Ni3Al-Ni3V section. This structure results from fast kinetics of ordering in the fcc → L12 and fcc → DO22 phase transitions. Four main stages in the microstructural evolution were observed. Stage I is the formation of spheroidal coherent L12 clusters in a disordered fcc matrix. During stage II the L12 clusters transform into cuboidal precipitates, and the fcc matrix orders into three DO22 variants (which may have interfaces that are wetted by thin fcc layers). In stage III accommodation of misfit (elastic energy) between different phases and variants occurs by formation of (110) twins or a single variant of the DO22 phase and tetragonally strained lamellae of the L12 phase. Stage IV is a discontinuous coarsening process in which a coarse incoherent two-phase structure replaces the fine coherent one. Grains of the coarse structure are nucleated on high-angle boundaries of primary fcc or other surfaces. Many of the grains are found twinned.

Type
Articles
Information
Journal of Materials Research , Volume 9 , Issue 12 , December 1994 , pp. 3068 - 3082
Copyright
Copyright © Materials Research Society 1994

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

1Villars, P. and Calvert, L. D., Pearson's Handbook of Crystallographic Data for Intermetallic Phases (ASM, Materials Park, OH, 1991).Google Scholar
2Tanner, L. E. and Leamy, H. J., in Order-Disorder Transformations in Alloys, edited by Warlimont, H. (Springer-Verlag, Berlin, 1974), p. 181.Google Scholar
3Tanner, L. E., Phys. Status Solidi 30, 685 (1968); Tanner, L. E. and Ashby, M. F., Phys. Status Solidi 33, 59 (1969).Google Scholar
4Gaudron, R., Sarfati, M., Barrachin, M., Finel, A., Ducastelle, F., and Solal, F., J. Phys. (France) 2, 1145 (1992).CrossRefGoogle Scholar
5International Tables of Crystallography, Vol. A, edited by Hahn, T. (Reidel Publishing Co., Dordrecht, The Netherlands, 1978).Google Scholar
6Khachaturyan, A. G., Theory of Structural Transformations in Solids (John Wiley and Sons, New York, 1983).Google Scholar
7Allen, S. M. and Cahn, J. W., Acta Metall. 23, 1017 (1975).Google Scholar
8Soffa, W. A. and Laughlin, D. E., Acta Metall. 37, 3019 (1989).Google Scholar
9Leroux, C., Loiseau, A., Broddin, D., and van Tendeloo, G., Philos. Mag. B 64, 57 (1991).Google Scholar
10Richards, M. J. and Cahn, J. W., Acta Metall. 19, 1263 (1971).Google Scholar
11Kumar, K. S., Int. Mater. Rev. 35, 293 (1990).Google Scholar
12Myasnikova, K. P., Markiv, V. Ya., Pryakhina, L. I., and Motrychuk, G., Izv. Akad. Nauk SSSR, Metally 3, 222 (1977).Google Scholar
13Hong, Y. M., Mishima, Y., and Suzuki, T., in High Temperature Ordered Intermetallic Alloys III, edited by Liu, C. T., Taub, A. I., Stoloff, N. S., and Koch, C. C. (Mater. Res. Soc. Symp. Proc. 133, Pittsburgh, PA, 1989), p. 429.Google Scholar
14Livingston, J. D. and Cahn, J. W., Acta Metall. 22, 495 (1974).Google Scholar
15Christian, J. W., Theory of Phase Transformation in Solids (Pergamon Press, Oxford, 1975).Google Scholar
16McConnell, C., Metall. Trans. 19A, 159 (1988).Google Scholar