Microstructure of electromagnetic stirred semi-solid AZ91D alloy
(School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China)
Abstract: The microstructures of semi-solid AZ91D alloy stirred by rotationally electromagnetic field were studied. The shape of primary α-Mg phase is dendrite under conventional solidification condition and the primary α-Mg grains are changed to the fine rosette-like or granular grains under electromagnetic stirring condition. If the electromagnetic stirring frequencies are low, there are a large amount of fine rosette-like primary α-Mg grains and the fine rosette-like primary α-Mg grain in two dimensions belongs to a single grain in three dimensions; there are also many spherical primary α-Mg grains, they may belong to a single grain in three dimensions and the orientation differences of the grains between them are very small. If the electromagnetic stirring frequencies are high, a lot of the fine rosette-like primary α-Mg grains disappear and are converted into granular grains, and moreover, most of these granular grains belong to different grains in three dimensions.
Key words: semi-solid; magnesium alloy; electro-magnetic stirring; microstructure