Fabrication of functionally graded materials by a semi-solid forming process under magnetic field gradients

Nucleation behavior of bulk Ni–Cu alloy and pure Sb in High magnetic fields

“…By suppressing the thermal convection in the melt through the Lorentz force, the qualities of crystals with an electroconducting or partially electroconducting nature were improved [7,8], as well as more homogeneous microstructures of some monotectic [9], peritectic [10], and eutectic [4] alloys were obtained. On the other hand, several composite microstructures with a continuous change in the volume fraction of primary phases were fabricated by high magnetic field gradients [11][12][13]. Such fabrication was realized by the combining effects of the Lorentz force and magnetic force, by which the migration of the primary phases and solutes in the alloy melt was magnetic force-controlled.…”

In situ control of the distributions of alloying elements in alloys in liquid state using high magnetic field gradients

“…However, during the primary reaction, the density difference between the MnSb phase and the remaining Mn/Sb liquid is small and should not induce an obvious sedimentation of the crystallized primary phase under normal gravity conditions. Furthermore, by combining the earlier mentioned estimation of the average cooling rate ( $ 180 1C/s) and the temperature interval of the primary reaction for a Mn-89.7 wt% Sb alloy (586 1C liquidus temperature and 571 1C eutectic temperature lead to a 15 1C temperature interval), the duration of the primary reaction is estimated to be about 0.08 s. In a previous work [22], a similar alloy was heated to a mixture of dispersed MnSb particles and a liquid Mn/Sb matrix and then held under normal gravity conditions for more than 30 min. Its microstructure showed that there was no obvious segregation of the primary MnSb.…”

“…The aim is to explore the microstructural development of these materials during solidification process with the application of the magnetic force. Previous studies have suggested that on the basis of the magnetic force, the distribution of either the added particles [22] or the crystallized phases [20,23] in solidified alloys could be controlled and thus a complicated structure with segregated particles [22] or primary phases [20,23] was produced. Such control of the distribution was realized by the control of the migration of the particles or the solid phases in the liquid matrix during the solidification process by the magnetic force.…”

Material tailoring for functionally graded hollow cylinders and spheres

“…The interfaces between constituents can be eliminated or minimized when FGMs are fabricated by layering a molten mixture of two phases of different volume fractions. Various manufacturing techniques for FGMs have been discussed by [2,3].…”