Validated thermodynamic prediction of AlP and eutectic (Si) solidification sequence in Al-Si cast alloys

4th International Conference on Advances in Solidification Processes

材料科学;物理学

Liang, S.M.^1 ; Schmid-Fetzer, R.^1

Institute of Metallurgy, Clausthal University of Technology, Clausthal-Zellerfeld

D-38678, Germany^1

关键词: Eutectic microstructure;    Heterogeneous nucleation;    Hypoeutectic Al-Si alloy;    Solidification sequence;    Solidification simulation;    Thermodynamic calculations;    Thermodynamic description;    Thermodynamic predictions;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/117/1/012003/pdf
DOI  :  10.1088/1757-899X/117/1/012003

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The eutectic microstructure in hypoeutectic Al-Si cast alloys is strongly influenced by AlP particles which are potent nuclei for the eutectic (Si) phase. The solidification sequence of AlP and (Si) phases is, thus, crucial for the nucleation of eutectic silicon with marked impact on its morphology. This study presents this interdependence between Si- and P-compositions, relevant for Al-Si cast alloys, on the solidification sequence of AlP and (Si). These data are predicted from a series of thermodynamic calculations. The predictions are based on a self-consistent thermodynamic description of the Al-Si-P ternary alloy system developed recently. They are validated by independent experimental studies on microstructure and undercooling in hypoeutectic Al-Si alloys. A constrained Scheil solidification simulation technique is applied to predict the undercooling under clean heterogeneous nucleation conditions, validated by dedicated experimental observations on entrained droplets. These specific undercooling values may be very large and their quantitative dependence on Si and P content of the Al alloy is presented.