Development of In-Ladle Direct Thermal Control (DTC) Rheocasting Process
In recent year, various rheocasting methods, other than stirring in the semisolid state, have been developed to produce a fine globular primary phase in cast alloys. These new methods, called as slurry-on-demand, involve the controlled nucleation and growth/ripening of primary phase during partial solidification. In-Ladle direct thermal control (DTC) rheocasting has been competitively and successfully developed. It requires no processing equipment outside of the casting machine, no grain refinement procedure and no additional cycling time except for cooling down to the desired casting temperature. Process concept of In-Ladle DTC rheocasting is simply based on the fact that there is slurry and mush transition in the range of liquid fraction of 0.1 to 0.6 and the fact that the transition could be controlled by controlling the shape of solid and the relative energy. This study is mainly concerned about the feasibility to achieve semisolid slurry during partial solidification only through thermal and time control, this is, by In-Ladle DTC rheocasting. Based on the optimum conditions obtained by thermal modeling, microstructural evolution of Al alloys was carried out by In-Ladle DTC rheocasting. The fluidity was also investigated by In-Ladle DTC rheocasting for Al alloys.
C.G. Kang, S.K. Kim and S.Y. Lee
J. K. Lee et al., "Development of In-Ladle Direct Thermal Control (DTC) Rheocasting Process", Solid State Phenomena, Vols. 116-117, pp. 518-521, 2006