Abstract: An environmentally resistant gas turbine engine disk is disclosed. The disk includes a substrate metal having locally enriched surface regions, the locally enriched surface regions comprising alloying elements present in a higher percentage than found in the substrate metal. A method for making the disk and other articles is also disclosed. The method includes furnishing a plurality of powder particle substrates made of a substrate metal, providing a nonmetallic precursor of a metallic coating material, wherein the metallic coating material includes an alloying element that is thermophysically melt incompatible with the substrate metal, contacting the powder particle substrates with the nonmetallic precursor, and chemically reducing the nonmetallic precursor to form coated powder particles comprising the powder particle substrates having a surface-enriched layer of the metallic coating material thereon, wherein the step of chemically reducing is performed without melting the powder particle substrates.

Abstract: A superalloy has a composition of, in weight percent, from about 16.0 percent to about 22.4 percent cobalt, from about 6.6 percent to about 14.3 percent chromium, from about 1.4 percent to about 3.5 percent tantalum, from about 1.9 percent to about 4.0 percent tungsten, from about 1.9 percent to about 3.9 percent molybdenum, from about 0.03 percent to about 0.10 percent zirconium, from about 0.9 percent to about 3.0 percent niobium, from about 2.4 percent to about 4.6 percent titanium, from about 2.6 percent to about 4.8 percent aluminum, from 0 to about 2.5 percent rhenium, from about 0.02 percent to about 0.10 percent carbon, from about 0.02 percent to about 0.10 percent boron, balance nickel and minor amounts of impurities. The superalloy is advantageously utilized in aircraft gas turbine disks.

Abstract: Close-coupled atomization systems and methods employing non-axisymmetric gas flow have demonstrated superior efficiency in the production of fine superalloy powder, compared to conventional close-coupled atomization utilizing an axisymmetric annular gas orifice and an axisymmetric melt nozzle. A means has been devised for convening otherwise axisymmetric plenums into non-axisymmetric plenums that produce non-axisymmetric gas flow.

Abstract: An apparatus for producing a molten metal flow comprises a refining hearth having a water-cooled wall, and an entry flow channel through the wall of the hearth disposed tangentially to the wall such that a flow of molten metal introduced into the hearth through the entry flow channel flows tangentially to the wall of the hearth. The hearth further has an exit flow channel through the wall of the hearth disposed tangentially to the wall. The molten metal entering the refining hearth flows in a vortex pattern, aiding in the removal of solid particulate matter from the metal. The refining hearth may be agitated by an induction coil placed adjacent to the hearth. The exit flow may be through a number of adjacent exit flow channels to reduce its local velocity.

Abstract: A method for atomizing high temperature melts to achieve greater efficiency and smaller particle size is described. The method involves the employment of lower pressure gas coupled with an atomization nozzle larger than prior art structures. The atomization nozzle is part of a close coupled atomization structure having shallow depth dimension. The method allows atomization at melts with reduced likelihood of freeze off. The method reduces heat extraction from the melt while the melt is still contained in the atomization nozzle.

Abstract: Apparatus for close coupled atomization of melts of metals having high melting points with low superheats is taught. The atomization apparatus includes means for supplying melt to be atomized at the relatively low superheat, melt guide means for guiding the melt as a stream to an atomization zone and a gas supply and means for delivering the gas as a stream to the atomization zone where both the melt supply and gas supply to the atomization zone are in very close proximity. The melt supply has an inwardly tapered lower end disposed immediately above the atomization zone. The gas supply surrounds the melt guide tube and the gas is delivered as a jet against the melt emerging from the melt guide tube. The temperature of the gas impacting the end of the melt guide tube is very low because of the gas expansion.

Abstract: A process and apparatus for producing a spray of atomized metal droplets includes providing an apparatus that forms a spray of molten metal droplets, the apparatus including a metal source and a metal stream atomizer, producing a stream of liquid metal from the metal source, and atomizing the stream of liquid metal with the metal stream atomizer to form the spray of molten metal droplets. A controlled spray of atomized metal droplets is achieved by selectively varying the temperature of the droplets in the spray of molten metal droplets, the step of selectively varying including the step of varying the flow rate of metal produced by the metal source, responsive to a command signal, and sensing the operation of the apparatus and generating the command signal indicative of the operation of the apparatus. The step of atomizing may be accomplished by directing a flow of an atomizing gas at the stream of liquid metal, and then selectively controlling the flow rate of the atomizing gas.

Abstract: Apparatus for producing a metal powder includes a cooled hearth structure in which a metallic alloy is melted and a heat source above the hearth positioned to heat the melt in the hearth. The cooling of the hearth causes a protective hearth skull to form between the melt and the hearth itself. The hearth is placed within an environmental control chamber. A supply structure provides a continuous supply of the metallic alloy to the hearth structure from the exterior of the chamber. A metal powder producer is positioned to receive molten metal from the hearth, and a continuous stream of the molten alloy from the hearth is transferred to the metal powder producer. The transfer is accomplished by tipping the hearth or by teeming through an opening in the bottom of the hearth. The hearth structure can utilize two individual hearths, controllably arranged so that molten metal is drawn from one hearth while the other is recharged.

Abstract: An apparatus that controls the flow of a stream of metal, such as produced from the bottom of a hearth, includes a cylindrical metallic nozzle body having a hollow wall which includes a slit extending substantially parallel to the axis of the cylinder so that there is no electrical continuity around the nozzle wall across the slit. The walls of the cylinder are preferably formed of hollow tubes through which cooling water is passed. A sensor senses a performance characteristic of the apparatus, such as the temperature of the nozzle body. An induction heating coil surrounds the nozzle body, and a controllable induction heating power supply is connected to the induction heating coil to provide power. A controller controls the power provided to the induction heating coil by the induction heating power supply responsive to an output signal of the sensor, so that a selected performance characteristic of the apparatus may be maintained.

Abstract: A process and apparatus for producing a spray of atomized metal droplets includes providing an apparatus that forms a spray of molten metal droplets, the apparatus including a metal source and a metal stream atomizer, producing a stream of liquid metal from the metal source, and atomizing the stream of liquid metal with the metal stream atomizer to form the spray of molten metal droplets. A controlled spray of atomized metal droplets is achieved by selectively varying the temperature of the droplets in the spray of molten metal droplets, the step of selectively varying including the step of varying the flow rate of metal produced by the metal source, responsive to a command signal, and sensing the operation of the apparatus and generating the command signal indicative of the operation of the apparatus. The step of atomizing may be accomplished by directing a flow of an atomizing gas at the stream of liquid metal, and then selectively controlling the flow rate of the atomizing gas.

Abstract: An apparatus for producing solidified metals of high cleanliness removes floating matter such as oxides from the surface of molten metals prior to melt atomization. The apparatus includes a water-cooled melt vessel having a dam extending from a sidewall of the vessel at an acute angle to the sidewall. The dam extends above a preselected metal surface level of the interior of the vessel to form a floating matter trap region within the apex of the acute angle. There is a passageway through the dam sufficiently remote from the trap region that floating matter in the trap region is not in communication with the passageway. The passageway may be entirely below the metal surface level or extend from below the metal surface level to above the metal surface level, but sufficiently far away that floating matter can be forced away from the passageway, as by the herding action of a plasma torch.

Abstract: A transfer tube is produced comprised of a high density ceramic oxide tube having directly bonded to its outer surface wall a low density ceramic oxide shell.

Abstract: A transfer tube is produced comprised of a high density ceramic oxide tube having directly bonded to its outer surface wall a low density ceramic oxide shell.

Abstract: A transfer tube is produced comprised of a high density ceramic oxide tube having a low density multi-layered ceramic oxide shell directly bonded to its outer surface wall.

Abstract: A transfer tube is produced comprised of a high density ceramic oxide tube having a low density multi-layered ceramic oxide shell directly bonded to its outer surface wall.