Sage Journals: Discover world-class research

Abstract

A pure macroscopic two-dimensional numerical model has been developed, capable of capturing the effects of dendritic arm coarsening on the transport phenomena occurring during a binary alloy solidification process. The general continuum conservation equations are aptly modified to take into account shrinkage induced fluid flow. Simultaneously, the effective permeability of the mushy zone is numerically modelled according to the microscopic coarsening kinetics. Moreover, a new nodal latent heat updating algorithm is proposed that takes into account dendritic arm coarsening considerations. The numerical results are first tested against experimental results reported in the literature, corresponding to the solidification of an Al-Cu alloy in a bottom cooled cavity. It is concluded that dendritic arm coarsening leads to an increased effective permeability of the mushy region as well as an enhanced eutectic fraction of the solidified ingot. Consequently, an enhanced macrosegregation is predicted, compared with that dictated by shrinkage induced fluid flow alone. Physical insights are also developed regarding the effects of various parameters on the overall macrosegregation.

Get full access to this article

View all access options for this article.

References

BENNON

W. D.

and F. P. INCROPERA: Metall. Trans. B, 1987, 18B, 611— 616.

BECKERMANN

and VISKANTA

: Phys. Chem. Hydrodynam., 1988, 10, 195–213.

AMBERG

: Int. J. Heat Mass Transf, 1991, 34, 219–227.

VOLLER

V. R.

, CROSS

, and MARKATOS

N. C.

: Int. J. Numer. Meth. Eng., 1987, 24, 271–284.

BRENT

A. D.

, VOLLER

V. R.

, and REID

K. J.

: Numer. Heat Transf, 1988, 13, 297–318.

OGILVY

A. J. W.

and D. H. KIRKWOOD: App!. Sci. Res., 1987, 44, 43–49.

FLEMINGS

M. C.

: ‘Solidification processing'; 1974, New York, McGraw-Hill.

KURZ

and FISHER

D. J.

: ‘Fundamentals of solidification’; 1989, Aedermannsdorf, Switzerland, Trans Tech.

MORTENSON

: Metall. Trans. A, 1991, 22, 569–574.

10.

SUNDARRAJ

and V. R. VOLLER: Int. J. Heat Mass Transf, 1993, 36, 713–723.

11.

YOO

and R. VISKANTA: Int. J. Heat Mass Transf, 1997, 40, 3875–3882.

12.

GLICKMAN

M. E.

, SMITH

R. N.

, MARSH

S. P.

, and KUICLINSKI

: Metall. Trans. A., 1992, 23A, 659–667.

13.

RAPPAZ

and V. VOLLER: Metall. Trans. A, 1990, 21A, 749–753.

14.

THEVIK

H. J.

and A. MO: Int. J. Heat Mass Transf, 1997, 40, 2055— 2065.

15.

BENNON

W. D.

and F. P. INCROPERA: Int. J. Heat Mass Transf, 1987, 30, 2161–2170.

16.

CHANG

and D. M. STEFANESCU: Metall. Trans. A, 1996, 27A, 2708–2721.

17.

CHIANG

K. C.

and H. L. TSAI: Int. J. Heat Mass Transf, 1992,35, 1763— 1770.

18.

PATANKAR

S. V.

: ‘Numerical heat transfer and fluid flow'; 1980, Washington, DC, Hemisphere/McGraw-Hill.

19.

CHEN

J. H.

and H. L. TSAI: Int. J. Heat Mass Transf, 1993, 36, 3069— 3075.

20.

KATO

and J. R. CAHOON: Metall. Trans. A, 1985, 16A, 579–586.

21.

VOLLER

V. R.

and s. SUNDARRAJ: Int. J. Heat Mass Transf, 1995, 6, 1009–1018.

22.

MURAKAMI

, uu

C. Y.

, and OKAMATO

: in ‘Solidification processing’, (ed. Beech

and Jones

), 287–290; 1987, London, The Institute Of Metals.

Effects of dendritic arm coarsening on macroscopic modelling of solidification of binary alloys

Abstract

Get full access to this article

References