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115th anniversary of St. Petersburg State Polytechnic University
ArticleName System analysis of morphological evolution of steel dendrite structure
ArticleAuthor V. M. Golod, K. I. Emelyanov
ArticleAuthorData

Chair of Materials, Technology and Eguipment of Foundry Saint-Petersburg State PolytechnicaL University (Saint-Petersburg, Russia):

Golod V. M., Cand. Eng., Prof. of the Chair, e-mail: cheshire@front.ru
Emelyanov K. I., Post-graduate

Abstract

The article introduces the concept of the two-stage evolution of equiaxed dendritic crystallites during non-equilibrium solidification of multi-component iron-based alloys. The conditions for the formation of the initial dendritic structure with an uneven distribution of the ensemble of dendrite arm spacings are considered. It is shown that the subsequent diff usion coalescence of side branches leads to coarsening of dendrite arm spacings and the formation of local structural heterogeneity in the scale of individual dendrite and its nearest neighbors. Joint processes of heat exchange, the growth of crystallites (at mesoscale) and diffusion (at microscale) during the redistribution of alloy components between the phases and the formation of the dendritic structure are analyzed. The computation ratios to assess the initial dendrite arm spacing on the stage of free growth of dendritic branches and axes are shown. The system of equations and computational procedures to define by the Monte-Carlo method the secon dary dendrite arm spacing and their statistical distribution during evolution of the structure resulting from the coalescence of the side branches are presented. The contribution of different mechanisms of coalescence in the formation of local structural heterogeneity on the base of modeling were compared with experimental data. The deve loped method of numerical analysis of dendritic solidification can be used to improve estimates of the parameters of solidifi cation process as predictors structure in order to improve the adequacy of the forecast models.

keywords Dendritic structure, secondary dendrite arm spacing, diffusional coalescence, computer modeling, computational procedure, the Monte-Carlo method, non-equilibrium crystallization, local structural heterogeneity
References

1. Khvorinov N. I. Kristallizatsiya i neodnorodnost stali (Crystallization and heterogeneity of steel). Translated from Czech by A. A. Zhukov. Moscow : Mashgiz, 1958. 392 p.
2. Cicutti C., Boeri R. Development of an analytical model to predict the microsrtructure of continuously cast steel slab. Steel Research International. 2000. Vol. 71, No. 8. pp. 288–294.
3. Volkova O., Heller H. P., Janke D. Microstructure and cleanliness of rapidly solidifi ed steels. ISIJ International. 2003. Vol. 43, No. 11. pp. 1724–1732.
4. Pierer R., Bernhard C. On the influence of carbon on secondary dendrite arm spacing in steel. Journal of Materials Science. 2008. Vol. 43, No. 21. pp. 6938–6943.
5. Won Y. M., Thomas B. Simple model of microsegregation during solidification of steels. Metallurgical and Materials Transactions. 2001. Vol. 32A, No. 7. pp. 1755–1767.
6. Karlinski de Barcellos V. et al. Modeling of heat transfer, dendrite microstructure and grain size in continuous casting of steels. Steel Research International. 2010. Vol. 81, No. 6. pp. 461–471.
7. Golod V. M., Emelyanov K. I., Orlova I. G. Chernye Metally — Ferrous metals. 2013. No. 8. pp. 9–16.
8. Golod V. M., Savelev K. D., Basin A. S. Modelirovanie i kompyuternyy analiz kristallizatsii mnogokomponentnykh splavov na osnove zheleza (Modelling and computer analysis of crystallization of multicomponent iron-based alloys). Saint Petersburg : Publishing House of Polytechnical University, 2008. 372 p.
9. Golod V. M., Emelyanov K. I., Orlova I. Chernye Metally — Ferrous metals. 2013. No. 9. pp. 25–32.
10. Merton C. Flemings. Protsessy zatverdevaniya (Solidification Processing). Moscow : Mir, 1977. 423 p.
11. Kurz W., Fisher D. J. Fundamentalnye osnovy zatverdevaniya (Fundamentals of solidification). Moscow — Izhevsk : Institute of Computer Sciences, 2013. 300 p.
12. Nastac L., Stefanescu D. M. Macrotransport — solidification kinetics modeling of equiaxed dendritic growth: Part. 1. Model development and discussion. Metallurgical and Materials Transactions. 1996. Vol. 27A, No. 12. pp. 4061–4074.
13. Girshovich N. G. Kristallizatsiya i svoystva chuguna v otlivkakh (Crystallization and properties of cast iron in costings). Moscow : Mashinostroenie, 1966. 562 p.
14. Han Q., Hu H., Zhong X. Models for the isothermal coarsening of secondary dendrite arms in multicomponent alloys. Metallurgical and Materials Transactions. 1997. Vol. 28B, No. 6. pp. 1185–1187.
15. A guide to the solidifi cation of steels. Stockholm : Jernkontoret, 1977. 162 p.
16. Golod V. M., Emelyanov K. I., Orlova I. G. Chernye Metally — Ferrous metals. 2013. No. 11. pp. 18–25.

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