The columnar to equiaxed transition of horizontal unsteady-state directionally solidified Al-Si alloys

Materials Research

Diego B. Carvalho²  Antonio L. Moreira²  Daniel J. Moutinho¹  José M. Filho¹  Otávio L. Rocha¹  José E. Spinelli¹ 

[1] ,Federal University of Pará Institute of Technology Belém PA ,Brazil

关键词: columnar to equiaxed transition;    directional solidification;    thermal parameters;    unsteady-state conditions;    Al-Si alloys;   

DOI  :  10.1590/S1516-14392014005000015

来源: SciELO

【 摘 要 】

Experiments were conducted to investigate the influence of thermal parameters on the columnar to equiaxed transition during the horizontal unsteady-state directional solidification of Al-Si alloys. The parameters analyzed include the heat transfer coefficients, growth rates, cooling rates, temperature gradients and composition. A combined theoretical and experimental approach is developed to determine the solidification thermal variables considered. The increasing solute content in Al-Si alloys was not found to affect significantly the experimental position of the CET which occurred for cooling rates in the range between 0.35 and 0.64 K/s for any of three alloy compositions examined. A comparative analysis between the results of this work and those from the literature proposed to analyze the CET during upward vertical solidification of Al-Si alloys is reported and the results have shown that the end of the columnar region during horizontal directional solidification is abbreviated as a result of about six times higher thermal gradient than that verified during upward unidirectional solidification of alloys investigated.

【 授权许可】

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