An ICME Method for Predicting Phase Dissolution During Solution Treatment in Advanced Super Vacuum Die Cast Magnesium Alloys

Abstract

An integrated computational materials engineering (ICME) methodology was applied in this study to systematically and quantitatively study the second phase dissolution kinetics during the solution treatment process of a high pressure die cast magnesium sample. The study was conducted on Mg-9 wt% Al, Mg-5 wt% Al, and Mg-11 wt% Al binary alloys after isothermal solution treatments ranging from 380 to 420 °C. The experimental measurements revealed an exponential decrease of the volume fraction of the second β-phase (Mg 17 Al 12) during the solution treatment. A CALPHAD-based computational tool (Thermocalc DICTRA Diffusion Module) was used to simulate the dissolution process. In this study, measurements from as-cast samples were used as input parameters to improve the accuracy of the predicted results. An analytical, physics-based micro-model, based on the Johnson-Mehl-Avrami type equation, was also applied to study the dissolution kinetics. Both the simulation and micro-model quantitatively agree with the experimental results at all solution treatment temperatures. Calibration and verification of a few input parameters help to understand the assumptions made in the modeling, improve the accuracy of the prediction, and can be applicable in different Mg-Al binary alloys. Adopting such an ICME methodology for modeling development and verification in predicting the dissolution kinetics during solution treatment will allow for more rapid optimization of solution treatments procedures to be used in industrial applications.