Abstract: Method for forming a unitary component from a plurality of powder metallurgy compacts. The method in some embodiments includes fluidizing first and second surfaces, wherein a first powder metallurgy compact defines the first surface and a second powder metallurgy compact defines the second surface. The method also includes joining the fluidizing first and second surfaces to form a bonded structure and thermally treating the bonded structure to fuse the first and second compacts into a unitary component.

Abstract: Investment casting shells, methods for their manufacture and methods for casting metals and alloys using such shells are disclosed. One feature of the shells is that the facecoat plus interior backup layers are purposefully designed to have substantially similar coefficients of thermal expansion to the seal dip layers. This helps reduce the occurrence of dimensional casting defects caused by differential thermal expansions of the layers comprising the shell. One embodiment of such a shell comprises a facecoat, plural interior backup layers and plural intermediate backup layers wherein at least one of the plural intermediate backup layers comprises a material capable of undergoing a volumetric transformation during cool down, and wherein the seal-dip layers have a coefficient of thermal expansion that varies from the coefficient of thermal expansion of the facecoat and interior backup layers by less than about 10 percent.

Abstract: A method for casting long thin metal articles is described. A particular embodiment is directed to the casting of seals that are used in the low pressure turbine section of a gas turbine engine. The method first involves forming a mold, and then preheating the mold so that the temperature towards the upper portion of the mold is close to the liquidus temperature of the metal composition being cast. The temperature of the bottom portion of the mold is below the solidus temperature of the metal alloy composition. After the metal is poured into the mold cavity, the mold heating system preferably is moved at a selected rate so that the portion of the mold being heated by the furnace is slowly decreased. Withdrawal rates slower than about 30 inches per hour produce satisfactory casting results.

Abstract: A method and process for producing a yttrium oxide metal casting refractory composition is disclosed. Powdered Y.sub.2 O.sub.3 is combined with a sintering agent (preferably V.sub.2 O.sub.5) and an organic binder. The mixture is sintered and ground to produce a stable Y.sub.2 O.sub.3 flour. The flour is added to another binder having specific SiO.sub.2, hydrolysis and viscosity levels in order to produce a slurry. Slurries prepared in accordance with the invention avoid problems traditionally associated with Y.sub.2 O.sub.3 hydration and/or carbonation, and have long storage lives. In addition, the material costs associated with the slurries are low in comparison with products using fused Y.sub.2 O.sub.3. The Y.sub.2 O.sub.3 slurries may also find application as solid preformed cores formed by any conventional injection molding, transfer molding, or slurry casting process.

Abstract: A container for holding powdered metal is formed by electroplating a layer of metal over a pattern having a configuration which corresponds to the configuration of an article to be formed. A rigid core is surrounded by the pattern material and the layer of metal. The pattern material is removed from the layer of metal to form a container in which the core is disposed. The core and container may be held against relative movement by gripping the core with the layer of metal or by pin elements extending between the core and layer of metal. The container is filled with metal powder. The metal powder is cold compacted to plastically deform the particles of metal powder without significant bonding between the particles of metal powder. The metal powder is cold compacted by exposing the container to fluid at a relatively low temperature and high pressure.

Abstract: Y.sub.2 O.sub.3 is recovered from investment casting shell molds by introducing used mold materials into a dissolution reactor preferably consisting of a rotating vessel having an interior lining of acid and abrasion resistant material. An acid is combined with the materials in the reactor and agitated for a selected time period. Thereafter, the liquid remaining in the reactor is separated from the residual solids and removed. The liquid contains dissolved Y.sub.2 O.sub.3 which is precipitated, preferably using oxalic acid to produce yttrium oxalate [Y.sub.2 (C.sub.2 O.sub.4).sub.3.9H.sub.2 O]. The Y.sub.2 (C.sub.2 O.sub.4).sub.3.9H.sub.2 O is ultimately removed from the solution and calcined to produce high purity Y.sub.2 O.sub.3.

Abstract: A highly efficient method for recovering Y.sub.2 O.sub.3 from casting slurries and cores containing Y.sub.2 O.sub.3 in combination with a binder is disclosed. The slurry is first treated with a gelling agent which causes the slurry to gel. The gelled slurry is then ignited in order to remove residual organic compounds. After ignition, the product is crushed and pulverized to form a powder. Thereafter, the powder is calcined at a temperature sufficient to crystallize the silica binder in the powder. The calcined product is subsequently dissolved in a heated acid solution for a selected time period. The resulting solution contains dissolved Y.sub.2 O.sub.3 and undissolved binder residue, which is filtered and removed. The Y.sub.2 O.sub.3 in the solution is then diluted with deionized water, and precipitated, preferably using oxalic acid to produce yttrium oxalate. The yttrium oxalate is ultimately removed from the solution and calcined to produce high purity Y.sub.2 O.sub.3.