On the Choice of the Geometrical Extrapolation Models for the Mg-Al-Sr System Based on Experimental Investigation

Abstract

In the current work, solidification curves were deduced experimentally from Differential Scanning Calorimetric (DSC) using heat transfer model, then compare our experimental work with different extrapolation solidification curves models predicted based on thermodynamic properties of binary sub-systems. The motivation of this work is to better predict ternary thermodynamic properties for binary phase diagram and the error of predicting arises from misjudging the asymmetric component in the asymmetric geometric model, It was found that Kohler gives a better agreement than Muggianu (symmetric model). Tested alloys show that, choosing strontium (Sr) element as the asymmetric component in Mg-Al-Sr system gives the best prediction for solidification curves. In addition, the solidification curves calculated using Toop model for the ternary system (Al or Mg is asymmetric) shows the poorest fit solidification curves construed from DSC data.

Keywords:
Symmetric/asymmetric model; Heat transfer model (HTM); DSC