Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-29T07:29:01.402Z Has data issue: false hasContentIssue false
  • English
  • Français

Nanoscale Phase Separation Induced by Mechanical Alloying in the Iron-Erbium-Nitrogen System

Published online by Cambridge University Press:  28 February 2011

Z. Fu ,
H. J. Fecht  and
W. L. Johnson
Z. Fu
Affiliation:
Department of Materials Science, Keck Lab., California Institute of Technology, Pasadena, CA 91125
H. J. Fecht
Affiliation:
Department of Materials Science, Keck Lab., California Institute of Technology, Pasadena, CA 91125
W. L. Johnson
Affiliation:
Department of Materials Science, Keck Lab., California Institute of Technology, Pasadena, CA 91125
Get access

Abstract

Metastable phases, including nanocrystalline and amorphous structures, can be prepared by high energy cyclic deformation processes. In the present study, we compare the behavior of a stable congruent melting compound (Fe2Er Laves phase) with a mixture of pure elemental Fe and Er powders subjected to high energy ball milling. X-ray diffraction and transmission electron microscopy reveal similar results in both cases. In the early stages, a nanocrystalline fcc phase with lattice parameter a = 0.484 nm and a grain size of 6 nm is formed together with a bcc Fe-rich phase. Extended milling results in a nanoscale phase separation into Fe-rich and Er-rich crystallites with average grain sizes of 1.8-4 nm. Based on a lattice parameter analysis, the fcc phase was initially thought to be a metastable FeEr3 phase. Further studies revealed nitrogen gas in the milling vial had reacted with the powder during ball milling to produce the cubic ErN phase (“NaCl” structure with a lattice parameter of 0.4836 nm). Our experiments demonstrate that the steel vials for ball milling do not remain hermetically sealed during the milling process and a nitride phase can be formed easily if a catalyst for the dissociation of nitrogen molecules (such as Fe) exists in the system.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 186: Symposium I – Alloy Phase Stability and Design , 1990 , 169
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

[1] Benjamin, J. S., Sci. Am., 234 40 (1976)Google Scholar
[2] Koch, C. C., Cavin, O. B. et al. Appl. Phys. Lett., 43 1017 (1983)Google Scholar
[3] Schwarz, R. B., Petrich, R. R. and Saw, C. K., J. Non-Cryst. Solids, 76 281 (1985); E. Hellstern and L. Schultz, Appl. Phys. Lett., 48 124 (1986); L. Schultz, J. Less-Common. Met., 145 233 (1988).Google Scholar
[4] Hellstern, E., Fecht, H. J., Fu, Z. and Johnson, W. L., J. Appl. Phys., 65 305 (1989)Google Scholar
[5] Fecht, H. J., Hellstern, E., Fu, Z. and Johnson, W. L., Adv. Powd. Met.. 2 111 (1989)Google Scholar
[6] Fecht, H. J., Han, G., Fu, Z. and Johnson, W. L., J. Appl. Phys. Feb. 4 1744 (1989)Google Scholar
[7] Fecht, H. J., Fu, Z. and Johnson, W.L., Phys. Rev. Letts. 64 (15) (1990) ; K. Aoki, A. Yanagitani, X.-G. Li and T. Masumoto, Mat. Sci. Engg. 97, 35 (1988)Google Scholar
[8] Massalski, T. B., Binary alloy Phase Diagrams, (Metals Park, Ohio: American Society for Metals, 1986) P1015 Google Scholar
[9] Cullity, B. D., Elements of X-ray Diffraction, 2nd. edition, (Addison-Wesley Publishing Company, Inc., 1978) p102 Google Scholar
[10] Loeff, P.I. and Bakker, H., Europhys. Lett.. 8, 35 (1989)Google Scholar
[11] Massalski, T. B., Physical Metallurgy, 3rd. Edition, (Elsevier Science Publishers B.V., 1983)Google Scholar
[12] Huber, K. P. and Herzberg, G., Molecular Spectra and Molecula Structure IV. Constants of Diatomic Molecules, (Von Nostrand Reinhold Company,1979)Google Scholar
[13] Guinier, A., X-ray Diffraction, (Freeman, San Francisco, 1963) p 124 Google Scholar
[14] Friedel, J., Dislocations, (Pergamon, Oxford, 1964) p 418 Google Scholar