Hostname: page-component-84b7d79bbc-l82ql Total loading time: 0 Render date: 2024-07-30T09:26:58.125Z Has data issue: false hasContentIssue false
  • English
  • Français

Modeling the Diffusion-Controlled Growth of Needle and Plate-Shaped Precipitates

Published online by Cambridge University Press:  01 February 2011

Z. Guo  and
W. Sha
Z. Guo
Affiliation:
Metals Research Group, School of Civil Engineering, Queen's University of Belfast, UK
W. Sha
Affiliation:
Metals Research Group, School of Civil Engineering, Queen's University of Belfast, UK
Get access

Abstract

Various theories have been developed to describe the diffusion-controlled growth of precipitates with shapes approximating needles or plates. The most comprehensive one is due to Ivantsov, Horvay and Cahn, and Trivedi (HIT theory), where all the factors that may influence the precipitate growth, i.e. diffusion, interface kinetics and capillarity, are accounted for within one equation. However, HIT theory was developed based on assumptions that transformation strain/stress and interfacial free energy are isotropic, which are not true in most of the real systems. An improved growth theory of precipitates of needle and plate shapes was developed in the present study. A new concept, the compression ratio, was introduced to account for influences from the anisotropy of transformation strain/stress and interfacial free energy on the precipitate morphology. Experimental evidence supports such compression effect. Precipitate growth kinetics were quantified using this concept. The improved HIT theory (IHIT theory) was then applied to study the growth of Widmanstatten austenite in ferrite in Fe-C-Mn steels. The calculated results agree well with the experimental observations.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 731: Symposium W – Modeling and Numerical Simulation of Materials Behavior and Evolution , 2002 , W7.5
Copyright
Copyright © Materials Research Society 2002

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. Christian, J.W., Theory of Transformations in Metals and Alloys, 2nd ed., Part 1, (Pergamon, Oxford, 1975)Google Scholar
2. Trivedi, R., Acta Metall. 18, 287–296 (1970)Google Scholar
3. Trivedi, R., Metall. Trans. 1, 921–927 (1970)Google Scholar
4. Yost, F.G. and Trivedi, R., Metall. Trans. 3, 2371–2380 (1972)Google Scholar
5. Ivantsov, G.P., Dokl. Akad. Nauk, SSSR, 58, 567–569 (1947)Google Scholar
6. Ivantsov, G.P., Growth of Crystals, Vol.3, (Consultants Bureau, New York, 1960)Google Scholar
7. Horvay, G. and Cahn, J.W., Acta Metall. 9, 695–705 (1961)Google Scholar
8. Bosze, W.P. and Trivedi, R., Metall. Trans. 5, 511–512 (1974)Google Scholar
9. Guo, Z. and Sha, W., Growth Theory of Needle and Plate Shaped Precipitates, submitted to Acta Mater., (2001)Google Scholar
10. Rivera-Diaz-del-Castillo, P.E.J. and Bhadeshia, H.K.D.H., Mater. Sci. Technol. 17, 25–29 (2001)Google Scholar
11. Zener, C., Trans. AIME 167, 550–595 (1946)Google Scholar
12. Bhadeshia, H.K.D.H., Mater. Sci. Technol. 1, 497–504 (1985)Google Scholar
13. Gupta, S.P., Z. Metallkd. 90, 182–188 (1999)Google Scholar
14. Speich, G.R., Demarest, V.A. and Miller, R.A., Metall. Trans. 12, 1419 (1981)Google Scholar
15. Martin, J.W., Doherty, R.D. and Cantor, B., Stability of Microstructure in Metallic Systems, ed. 2nd ed. (University Press, Cambridge, 1997) p.242 Google Scholar
16. Brandes, E.A. and Brook, G.B., Smithells Metals Reference Book, ed. 7th ed. (ButterworthHeinemann Ltd., Oxford, 1992), p.13_20 Google Scholar