Abstract
To determine the modifying agents for Al-7Si alloys, microstructure observation and mixing enthalpy analysis using Miedema model for Al-7Si alloy with additions of different rare earth elements were performed, and the effects of rare earth elements on the modification of eutectic silicon morphology were investigated. The results of mixing enthalpy analysis show that these four rare earth elements, La, Sm, Pr, and Ce, which have the large negative mixing enthalpies with Si, can be selected as modifying agents for eutectic silicon morphology. The element with the largest negative mixing enthalpy is Ce. Furthermore, the microstructures indicate that these four elements can effectively modify the eutectic (α)Al-Si crystals in Al-7Si alloy, and the most effective one is also Ce. Differential scanning calorimetry (DSC) results show that the eutectic temperature depressions due to the additions of modifying agents are the important reasons for the modification of eutectic (α)Al-Si crystals.
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This work was financially supported by the Research Fund of the State Key Laboratory of Solidification Processing (No.42-QP-009), the Open Fund of the State Key Laboratory of Solidification Processing in NWPU (No.201009), the Fundamental Research Fund of Northwestern Polytechnical University (No.JC200929), and the 111 Project of China (No.B08040).
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Chen, Zw., Ma, Cy. & Chen, P. Modifying agent selection for Al-7Si alloy by Miedema model. Int J Miner Metall Mater 19, 131–135 (2012). https://doi.org/10.1007/s12613-012-0527-0
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DOI: https://doi.org/10.1007/s12613-012-0527-0