Abstract: A directionally solidified nickel-base superalloy article has a defect therein extending parallel to the solidification direction. The article is repaired by removing any foreign matter present in the defect, and then heating the article to a repair temperature of from about 60 to about 98 percent of the solidus temperature of the base material in a chamber containing a protective gas that inhibits oxidation of the base material. The defect is filled with a filler metal while maintaining the article at the repair temperature. The filling is accomplished by providing a source of the filler metal of substantially the same composition as the base material of the directionally solidified article, and melting the filler metal into the defect progressively while moving the source of the filler metal relative to the article in a direction parallel to the solidification direction.

Abstract: A method for producing superalloy weld wire and weld wire having fewer inclusions, and specifically fewer hafnia inclusions, and superalloy weld wire, particularly hafnium-containing superalloy weld wire, produced by this method. The method includes producing directionally solidified cast rod in a diameter of less than about ½ inch. The rod preferably is produced by investment casting or by continuous casting. The directional solidification process results in rod having inclusions such as oxides and dirt segregated into portions of the casting where they are easily removed. The cast rod can then be formed into semi-finished weld wire using a single extrusion step, followed by grinding to the final required diameter.

Abstract: A directionally solidified nickel-base superalloy article has a defect therein extending parallel to the solidification direction. The article is repaired by removing any foreign matter present in the defect, and then heating the article to a repair temperature of from about 60 to about 98 percent of the solidus temperature of the base material in a chamber containing a protective gas that inhibits oxidation of the base material. The defect is filled with a filler metal while maintaining the article at the repair temperature. The filling is accomplished by providing a source of the filler metal of substantially the same composition as the base material of the directionally solidified article, and melting the filler metal into the defect progressively while moving the source of the filler metal relative to the article in a direction parallel to the solidification direction.

Abstract: A method for producing superalloy weld wire and weld wire having fewer inclusions, and specifically fewer hafnia inclusions, and superalloy weld wire, particularly hafnium-containing superalloy weld wire, produced by this method. The method includes producing directionally solidified cast rod in a diameter of less than about ½ inch. The rod preferably is produced by investment casting or by continuous casting. The directional solidification process results in rod having inclusions such as oxides and dirt segregated into portions of the casting where they are easily removed. The cast rod can then be formed into semi-finished weld wire using a single extrusion step, followed by grinding to the final required diameter.

Abstract: A directionally solidified nickel-base superalloy article has a defect therein extending parallel to the solidification direction. The article is repaired by removing any foreign matter present in the defect, and then heating the article to a repair temperature of from about 60 to about 98 percent of the solidus temperature of the base material in a chamber containing a protective gas that inhibits oxidation of the base material. The defect is filled with a filler metal while maintaining the article at the repair temperature. The filling is accomplished by providing a source of the filler metal of substantially the same composition as the base material of the directionally solidified article, and melting the filler metal into the defect progressively while moving the source of the filler metal relative to the article in a direction parallel to the solidification direction.

Abstract: An article, such as a gas turbine engine mixer, is made by providing a mold structure defining a thin-walled, hollow article, and a base metal that is subject to hot tear cracking when cast in a generally equiaxed polycrystalline form, such as Rene' 108 and Mar-M247. The article is fabricated by introducing the molten base metal into the mold structure, and directionally solidifying the base metal in the mold structure to form a directionally oriented structure. The directionally oriented structure may be formed of a single grain or oriented multiple grains.

Abstract: An article is welded, as in weld repair of a defect, by positioning a weld lift-off block at a location on the surface of the article adjacent to the intended location of the end of the weldment on the surface of the article. The weld lift-off block has a wedge shape including a base contacting the surface of the article, and an upper face angled upwardly from the base from a base leading edge. A weld pool is formed on the surface of the article by directly heating the surface of the article using a heat source. The heat source is moved relative to the surface of the article and onto the upper surface of the weld lift-off block by crossing the leading edge of the wedge, without discontinuing the direct heating of the article by the heat source. The heating of the article with the heat source is discontinued only after the heat source is directly heating the upper face of the weld lift-off block, and not the article.

Abstract: An article made of a nickel-base superalloy having a nil-ductility range from the solidus temperature of the alloy to about 600.degree. F. below the solidus temperature is welded, as for example in the weld repair of surface cracks, by removing foreign matter from the area to be welded, first stress relieving the article, adjusting the temperature of the article to a welding temperature of from about 1800.degree. F. to about 2100.degree. F., welding a preselected area in an inert atmosphere at the welding temperature, and second stress relieving the article. Welding is preferably accomplished by striking an arc in the preselected area so as to locally melt the alloy in the preselected area, providing a filler metal having the same composition as the nickel-based superalloy of the article, and feeding the filler metal into the arc so that the filler metal is melted and fused with the article to form a weldment upon solidification.

Abstract: A surface defect in a gamma titanium aluminide article is repaired by weld repairing the defect and thereafter sealing the surface-connected cracks in the weldment. The surface-connected cracks are repaired by applying to the region of the weldment a powder of a brazing filler metal that is compatible with the gamma titanium aluminide alloy and with the weldment, and thereafter heating the article to a brazing temperature above the liquidus of the brazing filler metal. The article is preferably hot isostatically pressed after the repair is completed to close internal defects that cannot otherwise be closed due to the surface connected cracks.

Abstract: An article made of a gamma titanium aluminide alloy is welded, as for example in the weld repair of surface cracks, by removing foreign matter from the area to be welded, first stress relieving the article, cooling the entire article to a welding temperature of from about 1000.degree. F. to about 1400.degree. F., welding a preselected region in an inert atmosphere at the welding temperature, and second stress relieving the article. Welding is preferably accomplished by striking an arc in the preselected region so as to locally melt the alloy in the preselected region, providing a filler metal having the same composition as the gamma titanium aluminide alloy of the article, and feeding the filler metal into the arc so that the filler metal is melted and fused with the article to form a weldment upon solidification.

Abstract: A hollow article is made by providing and diffusion bonding the opposing parts of an article made of an alpha-beta titanium alloy. Hydrogen is introduced into the surface of an internal cavity before, during, or after diffusion bonding. The article is heat treated with the hydrogen present, typically by solution treating and aging the hydrogen-containing bonded article. The result is the production of a microstructure at the internal surface of the cavity that is resistant to fatigue-crack initiation, while retaining a microstructure throughout the rest of the article that is resistant to fatigue-crack propagation. After heat treating, the hydrogen Is removed from the article, and any further heat treating and other operations are completed.

Abstract: A hollow article is made by providing and diffusion bonding the opposing parts of an article made of an alpha-beta titanium alloy. Hydrogen is introduced into the surface of an internal cavity before, during, or after diffusion bonding. The article is heat treated with the hydrogen present, typically by solution treating and aging the hydrogen-containing bonded article. The result is the production of a microstructure at the internal surface of the cavity that is resistant to fatigue-crack initiation, while retaining a microstructure throughout the rest of the article that is resistant to fatigue-crack propagation. After heat treating, the hydrogen is removed from the article, and any further heat treating and other operations are completed.

Abstract: A fluid-cooled article, such as a turbomachinery blading member, is provided with a fluid passage by a method of depositing a first material on a work surface of a mandrel by low pressure plasma deposition. A first member thus generated is separated from the mandrel. In one form, an inner surface of the first member is provided with a surface groove. After depositing a sacrificial material in the groove, a cover material is applied to entrap the sacrificial material. Removal of the sacrificial material provides the fluid passage.

Abstract: A directional solidification melting and self-casting apparatus is improved through the provision of a multi-zoned, self-casting furnace including the combination of an induction heated, insitu charge melting upper zone and a resistance heated lower zone.

Abstract: A commercially available cobalt-base alloy, sometimes called X-40 alloy, and having a relatively high carbon content, is improved to make it useful in the directional solidification casting process through the addition of a particular amount of aluminum sufficient to avoid severe reaction with casting cores and molds which include silica, without detrimental effect on mechanical properties.

Abstract: A precision investment casting ceramic mold of the self-casting type is made as a unitary mold by providing separately a pattern for a wax charge-holding assembly and a pattern for a wax article casting assembly, each including an alignment portion. The two patterns are secured together at the alignment portions and are supported and located one with respect to the other by a plurality of supporting and locating members. The assembled patterns then are used in the conventional manner to make a ceramic casting mold.