Abstract: There is provided cryogenic milled copper alloys and methods of making the alloys. The alloys are fine grained and possess desirable physical properties stemming from the fine grain size. Embodiments include desirable physical properties, such as potentially high strength. Some embodiments of the cryogenic milled copper alloys may also be tailored for ductility, toughness, fracture resistance, corrosion resistance, fatigue resistance and other physical properties by balancing the alloy composition. In addition, embodiments of the alloys generally do not require extensive or expensive post-cryogenic milling processing.

Abstract: A method of producing high strength nanophase metal alloy powder by cryomilling metal powder under conditions which cause the formation of intrinsic nitrides, and of producing high strength metal articles by subjecting the nitrided cryomilled powder to thermo-mechanical processing. The intrinsic nitrides present within the alloy significantly reduce grain growth during thermo-mechanical processing, resulting in formed metal products of high strength and improved ductility.

Abstract: A method for manufacturing a net-shaped bimetallic part that includes the steps of: providing a tool that defines a cavity and a tooling surface; depositing a layer of an environmental metal material onto the tooling surface; filling the cavity in the tool with a powdered metal material; and simultaneously heating the tool and subjecting the tool to a pressurized gas to consolidate the powdered metal material and diffusion bond the environmental metal material to the consolidated powdered metal material to form a bimetallic part.

Abstract: A nanophase composite duct assembly and method of fabricating the same are provided that comprise an ultra-high strength nanophase aluminum alloy duct joined with a ceramic particulate reinforced metal matrix fitting, preferably using solid-state friction welding. The nanophase aluminum alloy duct is fabricated by extruding a billet formed by a process of cryogenic milling the alloy, followed by out-gassing, then hot isostatic pressing. The fitting is fabricated by combining a ceramic particulate with a metal matrix, preferably by powder processing or liquid metal infiltration. Further, the solid-state friction welding may comprise inertial welding, friction stir welding, or a combination thereof. As a result, a lightweight duct assembly is provided for high-pressure liquids such as propellants in rocket engines.

Abstract: A nanophase composite duct assembly and method of fabricating the same are provided that comprise an ultra-high strength nanophase aluminum alloy duct joined with a ceramic particulate reinforced metal matrix fitting, preferably using solid-state friction welding. The nanophase aluminum alloy duct is fabricated by extruding a billet formed by a process of cryogenic milling the alloy, followed by out-gassing, then hot isostatic pressing. The fitting is fabricated by combining a ceramic particulate with a metal matrix, preferably by powder processing or liquid metal infiltration. Further, the solid-state friction welding may comprise inertial welding, friction stir welding, or a combination thereof. As a result, a lightweight duct assembly is provided for high-pressure liquids such as propellants in rocket engines.

Abstract: A method of producing high strength nanophase metal alloy powder by cryomilling metal powder under conditions which cause the formation of intrinsic nitrides, and of producing high strength metal articles by subjecting the nitrided cryomilled powder to thermo-mechanical processing. The intrinsic nitrides present within the alloy significantly reduce grain growth during thermo-mechanical processing, resulting in formed metal products of high strength and improved ductility.

Abstract: High strength aluminum alloy rivets are provided in which the aluminum alloys exhibit high strength at atmospheric temperatures and maintain high strength and ductility at extremely low temperatures. The rivets are produced from an alloy which is made by blending about 89 atomic % to 99 atomic % aluminum, 1 atomic % to 11 atomic % of a secondary metal selected from the group consisting of magnesium, lithium, silicon, titanium, zirconium, and combinations thereof, and up to about 10 atomic % of a tertiary metal selected from the group consisting of Be, Ca, Sr, Ba, Ra, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, W, and combinations thereof. The alloy is produced by nanostructure material synthesis, such as cryomilling, in the absence of extrinsically added refractory dispersoids. The synthesized alloy is then consolidated and formed into a solid or blind rivet. Grain size within the rivet is less than 0.

Abstract: A method for manufacturing a net-shaped bimetallic part that includes the steps of: providing a tool that defines a cavity and a tooling surface; depositing a layer of an environmental metal material onto the tooling surface; filling the cavity in the tool with a powdered metal material; and simultaneously heating the tool and subjecting the tool to a pressurized gas to consolidate the powdered metal material and diffusion bond the environmental metal material to the consolidated powdered metal material to form a bimetallic part.

Abstract: A turbine disk assembly having an integrally bladed turbine disk and a plurality of captured damper members. The integrally bladed turbine disk includes a plurality of turbine blades that terminate at an integral tip shroud. A damper aperture is formed between each pair of adjacent integral tip shrouds and includes a first slotted portion and a second slotted portion. The first slotted portion is formed concentric to the two adjacent integral tip shrouds, extending circumferentially and axially through the two adjacent integral tip shrouds. The second slotted portion extends radially outwardly between the two adjacent integral tip shrouds. One of the damper members is disposed in the first slotted portion of the an associated damper aperture and frictionally engages at least one surface of each of the two adjacent tip shrouds to dissipate energy when relative motion occurs between the two adjacent integral tip shrouds to dampen vibration.

Abstract: A method of free form fabrication of metallic components, typically using computer aided design data, comprises selective laser binding and transient liquid sintering of blended powders. The powder blend includes a base metal alloy, a lower melting temperature alloy, and a polymer binder that constitutes approximately 5-15% of the total blend. A preform part is built up, layer-by-layer, by localized laser melting of the polymer constituent, which rapidly resolidifies to bind the metal particles. The binder is eliminated from the preform part by heating in a vacuum furnace at low atmospheric pressure. The preform part may require support during elimination of the polymer binder and subsequent densification by controlled heat treatment. Densification is performed at a temperature above the melting point of the lower temperature alloy but below the melting point of the base metal alloy to produce transient liquid sintering of the part to near full density with desired shape and dimensional tolerances.

Abstract: In the construction of cylindrical tanks having end domes wherein the domes are attached by stir friction welding, a wagon wheel is placed inside the tank at the interface of the tank cylinder and the dome such that it provides backup support for the pressure exerted by the stir friction welding tool and strengthens the weld area and the tank by being welded into the tank by the stir friction welding process.

Abstract: A method of superplastic extrusion is provided for fabricating large, complex-shaped, high strength metal alloy components, such as large, thin cross section, closed-box panels or integrally "T-stiffened" aircraft skin panels. Superplastic extrusion is similar to conventional extrusion except that strain rate and temperature are carefully controlled to keep an ultra-fine grain high strength metal alloy within the superplastic regime where deformation occurs through grain boundary sliding. A high strength, heat treatable metal alloy is first processed, such as by equal channel angular extrusion (ECAE), to have a uniform, equiaxed, ultra-fine grain size in thick section billet form. Temperature and strain rate are controlled during superplastic extrusion of the ultra-fine grained billet so that the stresses required for metal flow are much lower than those needed in conventional extrusion.

Abstract: A method is provided for fabricating metal matrix composites. Optical or reinforcing fibers, which may be in the form of monofilaments, mats, or tow, are consolidated into a metal matrix alloy. Grooves may be provided in the metal matrix material for holding and positioning the fibers. A transient liquid diffusion bonding agent in the form of a powder may be blended with powdered filler material, such as powdered matrix material, to provide a vehicle for consolidating the fibers into the metal matrix. The fibers and the blended powder are placed between layers of the metal matrix material and the whole structure is heated under minimal pressure to liquefy the bonding agent. The liquid bonding agent wets each fiber and interdiffuses with the matrix material, resulting in rapid isothermal solidification of the alloy and consolidation of the fibers in the matrix.

Abstract: A method and apparatus for effecting superplastic forming of metal workpieces at temperatures greater than 1000.degree. C., wherein both oxidation and creep deformation of the tooling are minimized. The process is achieved by heating forming surfaces of ceramic forming dies to temperatures in excess of 1000.degree. C., and using metal housings to impart high loading conditions to seal the workpiece within a chamber for superplastic forming. More specifically, the metal housings are used not only for load bearing purposes, but also for creating an evacuated chamber within which superplastic forming can take place. The ceramic dies, on the other hand, are positioned on opposing sides of the workpiece region to be superplastically formed, and are insulated from, while being contained within, the metallic dies.

Abstract: Diffusion bonding of aluminum alloys is performed using a thin alloy interlayer placed between mating surfaces of the alloy members to be bonded, the interlayer having a specific composition which is dependent upon the composition of the alloy members, the diffusion bonding temperature, the interdiffusion rates of the alloy members compared with the interlayer, and the solid state diffusion rate of the interlayer into the alloy members. The process is preferably further characterized by isothermal solidification of the interlayer after the diffusion bonding temperature has been reached.

Abstract: A method for forming monolithic structures from a plurality of aluminum or aluminum alloy sheets is provided which integrates a method for producing a selective fine grain structure in each of the sheets, with roll bonding and superplastic forming. The sheets are subjected to isothermal aging or controlled slow cooling to obtain a desired grain size in each of the respective sheets. Different heating and cooling treatments can be individually applied to each of the sheets so that the sheets can be tailored to have a fine grain or a coarser grain. Stop-off material is applied at selected areas of the sheets, and the resulting stack of sheets is subjected to cold roll bonding to bond adjacent surfaces of the sheets where stop-off material has not been applied. The roll bonding step also serves to plastically deform the sheets. The roll-bonded stack of sheets is then subjected to rapid heating for recrystallization of one or more of the sheets into a fine grain structure.

Abstract: A process is disclosed for bonding multi-layer sheet structure by using controlled depth laser welding. The laser energy may be applied in stages, whereby the inner sheets are first welded together and, the outer sheets are then joined thereto. The sheets are thereafter expanded to form the desired structure. Although the laser energy may be varied to control the depth of penetration, one embodiment utilizes a shield material to be applied between two sheets to prevent the laser energy from penetrating and joining the two sheets together. Similarly, shields may be used to control the width of the laser weld.

Abstract: A method is provided for obtaining a fine grain structure in 2000 and 7000 series aluminum alloys. The alloy is solution treated and overaged to provide a suitable precipitate. It is then softened and stabilized so that it can be cold rolled at room temperature without cracking. After cold rolling, the alloy is held at a recrystallization temperature so that new grains are nucleated and grow to form a fine grain structure.