Kyushu Institute of Technology, Kitakyushu 804-8550
Computer simulation of the upward cellular solidification of Al-Cu alloy was carried out considering the solidification to be a reaction controlled by diffusion. In the simulation, direct solving method of differential equation was applied to the diffusion in solid and liquid in contact with each other during cooling. The results of simulation showed that the solute distribution in liquid groove ahead of the solid-liquid interface is parabola whose bottom zenith lies at cell boundary. These results, together with the negligible diffusion in solid, showed that Scheil's equation is approximately applicable to the solute distribution in the solid cell after the solidification. Numerical analysis of the simulated results yielded a general equation which expresses the parabolic relationship between cooling rate and the cell size. The validity of equation thus induced was verified by the experimental results obtained by other researchers. The transition of planar/cellular interface in solidification was also investigated from the standpoint of the diffusion controlled solidification.
solute redistribution, upward cellular solidification, computer simulation, diffusion control, parabolic relation, interface transition
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