Experimental and Diffusion Simulation for the Homogenization of As-cast Mg-Al, Mg-Zn, and Mg-Al-Zn Alloys

Abstract

Annealing of as-cast Mg-Al alloys (3, 6, and 9 wt pct Al) and Mg-Zn alloys (1.5, 4.0, and 5.5 wt pct Zn) was performed at 603 K and 673 K (330 °C and 400 °C) for 1, 2, 4, and 8 hours to systematically investigate the variation of second phase fraction and solute concentration profile in Mg matrix using SEM image analysis and EMPA-WDS, respectively. To calculate second phase fraction and solute concentration profile, a diffusion model considering the moving boundary was constructed, and the experimental results were successfully explained by the model. The expansion of model to ternary Mg-Al-Zn alloy is also described. This model can be used for the optimization of homogenization process of the Mg alloys.