Determination of solidification sequence of the AlMg9 alloy

Abstract

Foundry Al-Mg alloys play an important role in overall foundry industry of light metals due to their outstanding properties, although their solidification mechanism has not been clearly determined. Solidification overview of multicomponent technical AlMg9 alloy was obtained in this work. One of significant achievement was application of "disturbed" solidification method by quenching at exactly determined temperature to obtain frozen microstructure. This method enables correlation between characteristic temperatures of phase transformations and corresponding characteristics of microstructure constituent. Mathematical expression related to the quenching temperature and time enable prediction of microstructure development during solidification of AlMg9 alloy. Chemical composition determination of particular phases, carried out by energy dispersive spectroscopy (EDS), resulted in identification of Al x(MnFe) ySi z, Mg 2Si and Al 8Mg 5 phases. Temperature and time solidification sequence were determined and compared to the predicted ones, by phase diagram modeling. The change of particular phase ratio during solidification process was established also by mathematical modeling. These models offer an oversight of the required solidification microstructure development.