Hostname: page-component-7479d7b7d-t6hkb Total loading time: 0 Render date: 2024-07-11T00:29:56.361Z Has data issue: false hasContentIssue false
  • English
  • Français

Application of TDGL Model to B2 Type Ordering with Two Step Phase Separation in Fe-Ni-Al Alloys

Published online by Cambridge University Press:  05 April 2013

Ryuichiro Oguma ,
Syo Matsumura ,
Minoru Doi ,
Satoshi Hata  and
Keisuke Ogata
Ryuichiro Oguma
Affiliation:
Department of Applied Physics., Fukuoka University, Fukuoka 814-0180, Japan
Syo Matsumura
Affiliation:
Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan
Minoru Doi
Affiliation:
Department of Mechanical Engineering, Aichi Institute of Technology, Toyota 470-0392, Japan
Satoshi Hata
Affiliation:
Department of Electrical and Material Science, Kyushu University, Kasuga 816-8580, Japan
Keisuke Ogata
Affiliation:
Interdisciplinary Graduate School of Engineering Science, Kyushu University, Kasuga 816-8580, Japan
Get access

Abstract

Formation of domain structures in two-step phase separation in Fe-based Fe-Ni-Al alloys are investigated by applying a time-dependent Ginzburg-Landau (TDGL) model. The present authors recently developed a TDGL formulation for ordering processes of B2 and D03 in binary alloys, taking into account the symmetrical relationships between these ordered phases. In this formulation, multiple types of variants of the structures are represented by three order parameters which can be measured independently through crystal structure factors. Mean-field free energies are defined in a form of Landau type expansion with the order parameters and a composition parameter. Interfacial energies due to local variations of degrees of order and composition are given in a gradient square approximation. Kinetic equations for time-evolution of the order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of the mean-field free energies and the interfacial energy terms. On the other hand, coauthors have investigated domain structures in two-step phase separation of Fe-based Fe-Ni-Al alloys. The evolution of three-dimensional domain structures and composition profiles has been analyzed by electron tomography imaging and energy-dispersive X-ray spectroscopy. In this work the authors performed three-dimensional numerical simulations assuming the thermal processing. The results of the simulations well reproduced the characteristics of the micro-structures obtained from the observations.

Keywords

phase transformationmetaldiffusion
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1535: Symposium a – Proceedings of the Multiscale Materials Modeling 2012 Conference , 2013 , mmm12-a-0255
Copyright
Copyright © Materials Research Society 2013 

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

Oguma, R., Matsumura, S., and Eguchi, T., J. Phys.: Condens. Matter 20, 275225(9pp) (2008).Google Scholar
Cahn, J. W. and Hilliard, J. E., J. Chem. Phys. 28, 258–267 (1959).CrossRefGoogle Scholar
Luban, M., “Generalized Landau Theories” in Phase Transitions and Critical Phenomena, 5A, ed. Domb, C. and Green, M. S., (Academic Press, 1976) pp. 35–86.Google Scholar
Gunton, J. D., Miguel, M. S. and Sahni, P. S., “The Dynamics of First-order Phase Transitions” in Phase Transitions and Critical Phenomena, 8, ed. Domb, C. and Green, M. S., (Academic Press, 1983) pp. 267–482 Google Scholar