Three Dimensional (3D) Microstructural Characterization and Quantitative Analysis of Solidified Microstructures in Magnesium-Based Alloys

Magnesium alloys have the attractive combination of lightweight and strength. An understanding of solidification microstructures in these materials is important. An accurate means of quantifying microstructure in 3D is extremely important. In this study, we have used serial polishing and synchrotron-based x-ray tomography technique as a means of 3D characterization of the solidified microstructures of magnesium-based alloys. These models were also used to conduct quantitative analysis in 3D. The phase fraction and morphologies of intermetallics and α-Mg matrix phase were obtained. The phase fractions of β-Mg₁₇Al₁₂ and Al-Mn intermetallics are consistent with measurements in the literature and calculations based on the Scheil-Gulliver solidification model. Our 3D reconstructions also show that the dendrite morphology has sixfold symmetry. The results of 3D microstructural characterization and analysis will enable a comprehensive understanding of solidification variables, microstructure, and properties.