Abstract: A method of purifying molten metal that reduces the amount of contaminants therein by maintaining the molten metal in a quiescent state allowing buoyant impurities in the metal to float to the top. The top of the molten metal is cooled solidifying the top portion and entrapping the impurities in the solid layer. The molten metal is then cast from beneath the solid portion.

Abstract: Ceramic porous bodies, including ceramic foam filters and smooth-faced ceramic objects, e.g., ceramic foam bricks, ceramic foam melting crucibles, and ceramic foam cores, made in accordance with the present invention are suitable for use with molten metal in general and molten superalloys in particular. The invention also provides a tundish for use with ceramic foam filters to filter metal en route from a metal furnace to a casting mold, and a melting device for use in casting metal which employs a ceramic foam filter as a bottom pour valve for a melting crucible such that the ceramic foam filter valve regulates the flow of molten metal therethrough in order to permit an entire ingot of metal to melt in the melting crucible before any metal begins to pour from the melting device into a casting mold.

Abstract: A method of forming a fine grained equiaxed ingot by melting metal and placing it in a mold having a restriction at the entrance disposed to solidify the metal in the entrance to the mold prior to complete solidification of the metal in the mold such that a shrinkage void is formed below the entrance to the mold. The ingot is then hot isostatically pressed (HIPped) to fully densify the ingot and eliminate the shrinkage void.

Abstract: An yttria-based slurry comprising a dense grain yttria powder and a non-aqueous-based binder is used as a mold facecoat and corecoat for investment casting of reactive metals such as titanium and titanium alloys.

Abstract: Ceramic porous bodies, including ceramic foam filters and smooth-faced ceramic objects, e.g., ceramic foam bricks, ceramic foam melting crucibles, and ceramic foam cores, made in accordance with the present invention are suitable for use with molten metal in general and molten superalloys in particular. The invention also provides a tundish for use with ceramic foam filters to filter metal en route from a metal furnace to a casting mold, and a melting device for use in casting metal which employs a ceramic foam filter as a bottom pour valve for a melting crucible such that the ceramic foam filter valve regulates the flow of molten metal therethrough in order to permit an entire ingot of metal to melt in the melting crucible before any metal begins to pour from the melting device into a casting mold.

Abstract: A high temperature alloy displaying excellent elevated temperature properties as well as low strategic metals content. Based on the iron/aluminum system, the alloy contains about 10 to 19% aluminum, 2 to 8% titanium, from about 0.5 to 10% molybdenium, from 0.1 to 1% hafnium and the balance substantially iron.

Abstract: A method of refining the microstructure of metals which undergo a phase transformation at high temperatures by diffusing a solute material into the metal at a temperature below the normal transformation temperature. The solute induces the phase transformation and removal of the solute at a temperature near the transformation temperature reverses the transformation. These phase transformations refine the microstructure of the metal so treated. The method is particularly useful to Group IVB metals i.e. Zr, Hf and Ti.

Abstract: Coatings for iron-, nickel- and cobalt-base superalloys. The coatings are applied in order to provide good oxidation and/or sulfidation and thermal fatigue resistance for the substrates to which the coatings are applied. The coatings consist essentially of, by weight, 10 to 50% chromium, 3 to 15% aluminum, 0.1 to 10% manganese, up to 8% tantalum, up to 5% tungsten, up to 5% reactive metal from the group consisting of lanthanum, yttrium and other rare earth elements, up to 5 percent of rare earth and/or refractory metal oxide particles, up to 12% silicon, up to 10% hafnium, and the balance selected from the group consisting of nickel, cobalt and iron, and combinations thereof. Additions of titanium up to 5% and noble metals up to 15% are also contemplated.

Abstract: A method and ceramic mold structure for use in producing articles having a predetermined crystalline orientation such as single crystals. The technique involves the use of a ceramic mold mounted on a chill plate with the mold defining a cavity tilted at an angle between about 5.degree. and 75.degree. relative to the vertical. One or more seed crystals are supported adjacent the chill plate and the orientation of the crystal is selected to provide a desired orientation in the resulting casting. The method results in improved solidification control, particularly with reference to avoiding defects caused by shrinkage.

Abstract: A mold construction and method for use in producing articles having a predetermined crystalline orientation including single crystals. The technique employs a seed holder or cradle that is inserted into a bottom aperture of a ceramic mold to permit the precise orientation of one or more seeds relative to the article cavity and to provide improved solidification process control. The technique also facilitates pattern assembly and pattern removal operations during fabrication of the ceramic mold.

Abstract: The microstructure of titanium is refined by inducing a high temperature transformation from .alpha.+.beta. to .beta. and back to .alpha.+.beta. by diffusing hydrogen into and then out of the metal while maintaining the metal above the temperature of hydride formation. The titanium is heated to a temperature just below the .alpha.+.beta. to .beta. transformation temperature, and hydrogen is diffused into the metal thereby inducing the phase change. The hydrogen is diffused out of the metal again inducing a phase change. When the hydrogen has been removed, the metal is allowed to cool to room temperature.

Abstract: A method and a support structure for use in casting metal articles which define at least one internal passage and wherein the support structure is associated with a core or cores employed during the casting operation. In that operation, the cores are confined within a disposable pattern, and a ceramic mold is formed around the pattern. When the pattern material is removed, a mold cavity is provided with the core positioned in the cavity to form the desired opening in the cast article. The support structure for the core comprises a member positioned between the core surface and the opposing mold surface. This member is encompassed by the pattern material when the pattern material is formed around the core. During the subsequent removal of the pattern material and also during curing of the ceramic mold, the support member serves to hold the core in place so that the dimension of the casting wall surrounding the internal passage can be precisely maintained.

Abstract: Coatings for iron-, nickel- and cobalt-base superalloys and the resulting coated components having good high temperature oxidation resistance. The coatings consist essentially of, by weight, 5% to 50% chromium, 3% to 30% aluminum, 0.01% to 15% tantalum, up to 10% manganese, up to 5% tungsten, up to 12% silicon, up to 10% hafnium, up to 5% reactive metal from the group consisting of lanthanum, yttrium, and other rare earth elements, up to 5% of rare earth and/or refractory metal oxide particles, and the balance selected from the group consisting of nickel, cobalt and iron, and combinations thereof. Additions of titanium up to 5% and noble metals up to 15% are also contemplated.

Abstract: Coatings for iron-, nickel- and cobalt-base superalloys. The coatings are applied in order to provide good oxidation and/or sulfidation and thermal fatigue resistance for the substrates to which the coatings are applied. The coatings consist essentially of, by weight, 10 to 50% chromium, 3 to 15% aluminum, 0.1 to 10% manganese, up to 8% tantalum, up to 5% tungsten, up to 5% reactive metal from the group consisting of lanthanum, yttrium and other rare earth elements, up to 5 percent of rare earth and/or refractory metal oxide particles, up to 12% silicon, up to 10% hafnium, and the balance selected from the group consisting of nickel, cobalt and iron, and combinations thereof. Additions of titanium up to 5% and noble metals up to 15% are also contemplated.

Abstract: Coatings for iron-, nickel- and cobalt-base superalloys. The coatings are applied in order to provide good oxidation/sulfidation and thermal fatigue resistance for the substrates to which the coatings are applied. The coatings consist essentially of, by weight, 10 to 50% chromium, 3 to 15% aluminum, 1.0 to 15% metal mixture from the group consisting of tantalum, tungsten, manganese and combinations thereof, up to 5% reactive metal from the group consisting of lanthanum, yttrium and other rare earth elements, up to 5 percent of rare earth and/or refractory metal oxide particles, and the balance selected from the group consisting of nickel, cobalt and iron, and combinations thereof. Additions of titanium up to 5% and noble metals up to 15% are also contemplated. Tantalum makes up at least 20% of the metal mixture or 0.5% of the total coating weight, whichever is greater. Tungsten, manganese, or a combination thereof, make up at least 0.5% of the total coating.

Abstract: A method for producing precision shapes which includes the consolidation of powder metal preforms into a shaped porous preform. A first coating is applied to the preform, this first coating being porous while providing a diffusion barrier. A second coating which is also initially porous is then applied and the coated preform can then be degasified by subjecting the preform to a vacuum, particularly at elevated temperatures. The coated preform is then heated under vacuum to a temperature such that the second coating is densified to the extent that it becomes non-porous. Finally, the preform is subjected to a hot isostatic pressing operation whereby formation of high integrity, fully dense metal shape results.

Abstract: A method for the production of metal articles resistant to corrosion at elevated temperatures. The method involves the application of a first coating on an article surface, this coating comprising a cobalt, iron or nickel alloy which is compatible with the substrate and which is ductile in character. A second coating highly resistant to corrosion at elevated temperatures is applied over the first coating to form a composite coating, and an elevated temperature treatment follows to provide interfacial bonding and to minimize the detrimental effects of thermal and mechanical stresses encountered during use. The provision of a ductile first layer provides a barrier against degradation of the corrosion resistance of the outer layer and serves as a barrier against detrimental interdiffusion and crack propagation.

Abstract: Cores for use in the casting of hollow metal parts by directional solidification from temperatures which may exceed 2700.degree. F., in which the strength, dimensional stability and shape of the core is maintained at such high temperatures by formulating the core to contain Cristobalite in an amount of at least 2.5% by weight.

Abstract: A shell mold for producing directionally solidified single crystal metal castings in which use is made of a crystal selector of helical shape wound about a support of a non heat disposable material which eliminates the need for providing a crystal selector of sufficient dimension for self support or other supporting means which may form a part of the pattern assembly about which the shell mold is formed.

Abstract: A process for providing coatings on metal articles whereby the articles will be resistant to corrosion at elevated temperatures. The process involves the application of an overlay on an article surface, the overlay comprising a ductile metal of a composition normally resistant to corrosion at elevated temperatures. An outer layer of aluminide or metal which is resistant to corrosion at elevated temperatures but which is subject to embrittlement at such temperatures is applied to complete the coating. Porosity in the coating is then eliminated and a high integrity corrosion resistant coating not subject to cracking is obtained by heating the article in a gaseous atmosphere to elevated temperature and simultaneously applying isostatic pressure to the article.