Abstract: A casting process and apparatus for producing directionally-solidified castings, and castings produced therewith. The process entails applying a facecoat slurry to a surface within a mold cavity to form a continuous solid facecoat on the surface, introducing a molten metal alloy into the mold cavity so that the molten metal alloy contacts the facecoat, and then immersing the mold in a liquid coolant to cool and solidify the molten metal alloy and form a casting of the metal alloy, during which an oxide layer forms on the casting surface. The facecoat is sufficiently adherent to the oxide layer such that at least a portion of the facecoat detaches from the mold surface and remains tightly adhered to the casting surface in the event the casting contracts during cooling. The facecoat contains at least 60 weight percent of a first phase of yttria, and the balance of the facecoat is a binder phase of an inorganic material.

Abstract: Molds 16 for casting molten materials using a directional solidification process and methods for forming a barrier layer between a liquid cooling medium 20 and a molten material of a casting process are provided. According to an embodiment, a mold 16 for casting a molten material comprises an inner surface at least partially coated with a metal oxide slurry 32 comprising metal oxide particles, wherein the metal oxide slurry 32 is capable of inhibiting a liquid cooling medium 20 from contacting a molten metal or metal alloy when the molten metal or metal alloy is disposed within an interior of the mold 16 and the mold 16 is disposed in the liquid cooling medium 20.

Abstract: A mold assembly for a liquid metal cooled directional solidification furnace having a cooling chamber provided with liquid metal and a heating chamber includes a mold member having a main body portion that defines an interior mold cavity. The mold member is adapted to be positioned in the heating chamber. The mold assembly also includes a chill-plate formed from a material having a thermal diffusivity a 600° K greater than approximately 10 E-6 m2/s, inert to at least one of molten tin and molten aluminum and adapted to be at least partially immersed in the liquid metal. The chill-plate includes a main body portion having a first surface extending to a second surface through an intermediate portion. The chill-plate is adapted to establish a thermal gradient between the mold member and the heating chamber.

Abstract: A shell mold for casting molten material to form an article is described. The mold includes a shell for containing the molten material, formed from at least one of yttrium silicates, zirconium silicates, hafnium silicates, and rare earth silicates. The mold also includes a facecoat disposed on an inner surface of the shell that contacts the molten material. The facecoat can be made from the materials described above. A method of casting a niobium-silicide article is also described, using the shell mold described herein. A method of making the ceramic shell mold is described as well, along with a slurry composition used in the manufacture of the shell mold.

Abstract: A mold is provided for enabling casting of single crystal metallic articles including a part-defining cavity, a sorter passage positioned vertically beneath and in fluid communication with the part-defining cavity, and a seed cavity positioned vertically beneath and in fluid communication with the sorter passage. The sorter passage includes a shape suitable for encouraging a single crystal structure in solidifying molten metal. Additionally, a portion of the mold between the sorter passage and the part-defining cavity includes a notch for facilitating breakage of a cast article proximate the notch during thermal stress build-up, so as to prevent mold breakage or the inclusion of part defects.

Abstract: A method for forming a dispersion-strengthened material containing nanoparticles that are uniformly dispersed in a matrix phase. The method includes adding nanoparticles and a molten material to a container to form a pool within the container and rotating the container to create a convection vortex in the pool. The convection vortex is sufficient to cause the nanoparticles to be incorporated into the molten material so as to yield a molten composite material, and further causes the molten composite material to be ejected from the container. The molten composite material is then cooled to form a solid composite body comprising a uniform dispersion of the nanoparticles.