Primary dendrite arm spacing during transient directional solidification of Al alloys with low redistribution coefficients

Abstract

Particular analytical expressions based on a curve fitting on numerical results for primary dendritic growth have been proposed in the literature to encompass binary alloy systems whose redistribution coefficient (k ₀) approaches zero. To date, these expressions have not been checked against experimental results of transient solidification. The present study developed a comparative analysis between the theoretical predictions furnished by such expressions and results from transient solidification experiments with low k ₀ aluminum alloys. The analysis has shown that the proposed approach generally describes the primary dendritic spacing during solidification of Al–Sn alloys which are characterized by very low k ₀ values as well as by very large solidification ranges.

Keywords:

• casting
• solidification
• aluminum alloys
• microstructural characterization

Acknowledgements

The authors acknowledge financial support provided by FAPESP (The Scientific Research Foundation of the State of São Paulo, Brazil), CNPq (The Brazilian Research Council), and FAEPEX-UNICAMP.