Phase distribution and phase structure control through a high gradient magnetic field during the solidification process

Influence of a high gradient magnetic field on the phase distribution and phase structure has been investigated experimentally. It was found that the application of a gradient magnetic field is capable of controlling the distribution of the primary phase in alloys. As a consequence, an axial gradient magnetic field causes the primary MnBi phase in Bi–6wt.%Mn alloy and the primary Si phase in Al–18wt.%Si alloy to segregate from the matrix; and the application of a radial gradient magnetic field produces a ring-like MnBi phase-rich layer. The application of an axial gradient magnetic field can produce the even refining structure during the electromagnetic vibration process of pure Al through restraining the formation of crystal rains. The gradient magnetic field also affects microstructure by aligning the phase and controlling the phase aggregation process. Moreover, the investigation on the influence of an axial gradient magnetic field on the distribution of the element indicates that the field caused the Mn solute in Bi–6wt.%Mn alloy to separate from the Bi matrix.