A method and apparatus for directionally controlled rapid solidification of a molten metal casting provides modified mold flasks containing mold media defining a mold cavity into which molten metal is poured and thereafter solidified. The mold media is fluid permeable and electrically and thermally conductive so that coolants passing through the media conduct heat away from the molten metal to promote solidification. Apparatus carried upon and within the mold flask allow controlled application of coolants to dissipate heat in a controlled manner to promote solidification in a controlled direction. Ports defined in the flasks, spaces between the mold media particulates and coolant, directionally applied by a movable cooling ring provide controlled directional cooling and castings having improved mechanical characteristics, with greater speed and increased efficiency.