Modelling the Solidification Microstructure Formation of Cobalt Dendritic Alloys
Tóm tắt
In the present work a mathematical model has been developed to explain the microstructure characteristics obtained during the solidification process of dendritic cobalt alloys, under ordinary low cooling rate conditions. The model, taking into account physical aspects such as undercooling, cooling rate, solute diffusion, interfacial energy, and dendrite tip morphology, allowed results to explain the experimental microstructure changes observed when the processing conditions were varied. The mathematical model involved micro and macroscopic phenomena occurring during the solidification process of metallic alloys. The solutions of the governing equations were obtained applying a non-coupled scheme, which enables the possibility to simulate the solidification of complex geometry castings.
Tài liệu tham khảo
G. H. Meyer. The numerical solution of multidimensional Stefan problems: A survey, Moving Boundary Problems. Ed. D. G. Wilson, A. D. Solomon, P. T. Boees. Academic Press, 1978.
M. Rappaz and Ph. Thévoz, Acta Metall., 35, 1487 (1987).
W. J. Boettinger, A. A. Wheeler, B. T. Murray, G. B. McFadden, and R. Kobayashi. Calculation of alloy solidification morphologies using the phase field method. Modelling of casting, welding and advanced solidification processes IV. Ed. P. V. Voller and L. Katgerman. The Minerals, Metals and Materials Society (1993).
W. J. Boettinger and J. Warren. The phase field method: simulation of alloy dendritic solidification during recalescence. Metallurgical and Materials Transactions A. 27, 657-669 (1996).
W. Olfield. A quantitative approach to casting solidification: freezing of cast iron. ASM Transactions, 59, 955 (1966).
Ph. Thévoz. Modelisation de la solidification dendritique equiaxe. PhD Thesis, Ecole Polytechnique Federale de Lausanne (1988).
M. Rappaz. Modelling of microstructure in solidification processes. International Materials Review, 34, 93-123 (1989).
M. Volmer and A. Weber, Z. Phys. Chem. 119, 227 (1926).
R. Becker and W. Doring, Ann. Phys., 24, 719 (1935).
Trurnbull and J. C. Fisher, J. Chem. Phys., 17, 71 (1949).
D. Turnbull, J. Chem. Phys., 18, 198 (1950).
P. B. Crosley, A. W. Douglas and L. F. Mondolfo, Solidification of Metals, 110, 10 (1967).
B. Cantor and R. D. Doherty, Acta Metall., 27, 33 (1979).
J. H. Perepeszko, Proc. 2nd. Int. Conf. on “Rapid Solidification Processing,” Reston VA, Eds. R. Mehrabian, B. H. Kear and M. Cohen, (Claitors, Baton Rouge, 1980), p. 56.
C. V. Thompson and Spaepen, Acta Metall., 31, 2021 (1983).
J. H. Perepeszko, D. U. Furrer and D. A. Muller, en Dispersion “Strengthened Aluminum Alloys,” Eds. Y. W. Kim and W. Giffith (TMS-AIME Phoenix, 1988).
J. D. Hunt, Mater. Sci. Engineering, 65, 75 (1984).
I. Maxwell and A. Hellawell, Acta Metal., 23, 229 (1975).
D. M. Stefanescu et Kanetkar. Computer simulation of microstructural evolution. Ed. D. J. Srolovitz, TMS-AIME 1986.
I. Dustin and W. Kurz, Z. Metallkunde, 77, 265 (1986).
K. C. Su, I. Ohnaka, I. Yamauchi and T. Fukusako, en “The Physical Metallurgy of cast iron,” Eds. H. Frederiksson and M. Hillert, North Holland, p. 181 (1985).
W. Kurz. D. J. Fisher, Fundamental of solidification, Trans. Tech. Publications LTD (1986).
E. Scheil, Z. Metallkunde, 34, 70 (1942).
H. D. Brody and M. C. Flemings, Transactions of TMS-AIME, 236, 615 (1966).
T. W. Clyne and W. Kurz, Met. Trans., 12A, 965 (1981).