Microstructural Refinement Process of Pure Magnesium by Pulse Magnetic Field Treatment
The effects of pulsed magnetic field on the solidified structure of pure Mg were investigated. Fine uniform equiaxed grains are acquired in the whole ingot from the PMF treatment, in contrast with the coarse columnar grains observed in conventional casting, and the average grain size is refined to 260 m with a 5Hz PMF treatment. The mould size also affects the grain refinement and the most suitable inner diameter of the cylindrical mould is set at 50mm. Pulsed magnetic field increases melt convection during solidification, and the violent agitation causes warmer liquid to fracture the tip of columnar dendrites or to break off dendrite branches and promote the formation of an equiaxed structure, with the broken pieces transported into the bulk liquid acting as nuclei.
Zhengyi Jiang, Shanqing Li, Jianmin Zeng, Xiaoping Liao and Daoguo Yang
B. Wang et al., "Microstructural Refinement Process of Pure Magnesium by Pulse Magnetic Field Treatment", Advanced Materials Research, Vols. 189-193, pp. 3964-3967, 2011