Abstract: A method of producing a semi-solid material without stirring, including heating a metal alloy to form a metallic melt, transferring a select amount of the melt into a vessel, nucleating the melt by regulating the transferring of the melt into the vessel, and crystallizing the melt within the vessel by cooling the melt at a controlled rate to produce a semi-solid material having a microstructure comprising rounded solid particles dispersed in a liquid metal matrix. In one form of the invention, a temperature-controlled shot sleeve is provided for receiving and cooling an amount of metallic melt at a controlled rate to produce the semi-solid material. The shot sleeve has a number of heat transfer zones adapted to independently control the temperature of the melt disposed adjacent various portions of the shot sleeve. The shot sleeve also includes a ram operable to discharge the semi-solid material directly into a die mold to form a near-net-shape part.

Abstract: An apparatus for producing a metallic slurry material for use in semi-solid forming of a shaped part. The apparatus is generally comprised of a forming vessel and a thermal jacket. The forming vessel defines an inner volume for containing the metallic slurry material and has an outer surface. The thermal jacket has an inner surface disposed in thermal communication with the outer surface of the forming vessel to effectuate heat transfer therebetween. At least one of the forming vessel and the thermal jacket defines a number of grooves to limit the rate of heat transfer adjacent the grooves. In one embodiment, the forming vessel defines a plurality of axially-offset grooves extending about the entire periphery of the outer surface of the forming vessel. In another embodiment, a stator is disposed about the thermal jacket to impart an electromagnetic stirring force to the metallic slurry material contained within the forming vessel.

Abstract: An apparatus for producing a metallic slurry material for use in semi-solid forming of a shaped part. The apparatus is generally comprised of a forming vessel and a thermal jacket. The forming vessel defines an inner volume for containing the metallic slurry material and has an outer surface. The thermal jacket has an inner surface disposed in thermal communication with the outer surface of the forming vessel to effectuate heat transfer therebetween. At least one of the forming vessel and the thermal jacket defines a number of grooves to limit the rate of heat transfer adjacent the grooves. In one embodiment, the forming vessel defines a plurality of axially-offset grooves extending about the entire periphery of the outer surface of the forming vessel. In another embodiment, a stator is disposed about the thermal jacket to impart an electromagnetic stirring force to the metallic slurry material contained within the forming vessel.

Abstract: A method of producing a semi-solid material without stirring, including heating a metal alloy to form a metallic melt, transferring a select amount of the melt into a vessel, nucleating the melt by regulating the transferring of the melt into the vessel, and crystallizing the melt within the vessel by cooling the melt at a controlled rate to produce a semi-solid material having a microstructure comprising rounded solid particles dispersed in a liquid metal matrix. In one form of the invention, a temperature-controlled shot sleeve is provided for receiving and cooling an amount of metallic melt at a controlled rate to produce the semi-solid material. The shot sleeve has a number of heat transfer zones adapted to independently control the temperature of the melt disposed adjacent various portions of the shot sleeve. The shot sleeve also includes a ram operable to discharge the semi-solid material directly into a die mold to form a near-net-shape part.

Abstract: An apparatus for producing a metallic slurry material for use in semi-solid forming of a shaped part. The apparatus is generally comprised of a forming vessel and a thermal jacket. The forming vessel defines an inner volume for containing the metallic slurry material and has an outer surface. The thermal jacket has an inner surface disposed in thermal communication with the outer surface of the forming vessel to effectuate heat transfer therebetween. At least one of the forming vessel and the thermal jacket defines a number of grooves to limit the rate of heat transfer adjacent the grooves. In one embodiment, the forming vessel defines a plurality of axially-offset grooves extending about the entire periphery of the outer surface of the forming vessel. In another embodiment, a stator is disposed about the thermal jacket to impart an electromagnetic stirring force to the metallic slurry material contained within the forming vessel.

Abstract: A method of producing a semi-solid material without stirring, including heating a metal alloy to form a metallic melt, transferring a select amount of the melt into a vessel, nucleating the melt by regulating the transferring of the melt into the vessel, and crystallizing the melt within the vessel by cooling the melt at a controlled rate to produce a semi-solid material having a microstructure comprising rounded solid particles dispersed in a liquid metal matrix. In one form of the invention, a temperature-controlled shot sleeve is provided for receiving and cooling an amount of metallic melt at a controlled rate to produce the semi-solid material. The shot sleeve has a number of heat transfer zones adapted to independently control the temperature of the melt disposed adjacent various portions of the shot sleeve. The shot sleeve also includes a ram operable to discharge the semi-solid material directly into a die mold to form a near-net-shape part.

Abstract: This invention is directed to a control system and method of vacuum brazing of aluminum workpieces in a chamber wherein the combination of the partial pressure of water and the partial pressure of oxygen is adjusted to be within a determined desired combination pressure range as a function of the temperature within the chamber as the workpieces are heated up to a temperature of about 500.degree. C.

Abstract: Aluminum-based sheets or parts, such as formed aluminum assemblies contaminated with forming die lubricants, are cleaned by a solventless, thermal degreasing process at controlled temperature (about 300.degree.-400.degree. F.), and in specified atmospheres (reactive gas which is at least at atmospheric pressure) prior to brazing. The organic contaminates on the aluminum-based sheet or part are reacted with the reactive gas (air or oxygen) and removed from the surface of the sheet or part without disruption of the underlying protective oxide layer. Subsequent brazing is thereby facilitated.

Abstract: This specification is directed to a method of making a current collector (14) for a sodium/sulfur battery (10). The current collector so-made is electronically conductive and resistant to corrosive attack by sulfur/polysulfide melts. The method includes the step of forming the current collector for the sodium/sulfur battery from a composite material (16) formed of aluminum filled with electronically conductive fibers selected from the group of fibers consisting essentially of graphite fibers having a diameter up to 10 microns and silicon carbide fibers having a diameter in a range of 500-1000 angstroms.

Abstract: A method of brazing aluminum parts in an inert gas atmosphere is disclosed. The brazed filler metal is controlled to contain a ternary alloy of aluminum-silicon-magnesium and the base aluminum parts are controlled to contain a binary alloy of aluminum-magnesium. Magnesium in the base metal is controlled to 0.4-1.2% and in the filler metal it is controlled to 0.2-0.6%; in the filler metal only, silicon is controlled to 7-12%. The assembled base metal parts and filler metal are subjected to differential heating rates, one rate being limited to at least 50.degree. C./minute when the metal parts reach temperatures in the range of 400.degree.-550.degree. C., and a conventional rate when outside said temperature zone. As a result, three physical parameters are caused to occur simultaneously: initiation of porosity in oxide film on the metal parts, transport of magnesium to the oxide interface and reaction with the oxide, and initial melting of the filler metal as well as wettings of the oxide by the filler metal.

Abstract: A method of fluxless brazing of aluminum parts is disclosed. Gaseous species, such as O.sub.2 and H.sub.2 O, which inhibit wetting are controlled by rapid heating (at least 100.degree. C./min) through a critical temperature range (such as 400.degree.-590.degree. C.) during heat-up to brazing temperatures. The formation of porosity through the oxide film and the collection of a promoter and wetting agent at the interface with the oxide film will thus occur simultaneously precluding disruption of wetting action by gaseous O.sub.2 or H.sub.2 O. Wicking of the wetting agent through the film porosity in the critical temperature range will then take place because of the limited time available for the reaction of gaseous O.sub.2 and H.sub.2 O with the film to form a duplex oxide. Heating may be carried out in a vacuum of 10.sup.-3 Torr or less or in an inert atmosphere with pulsed heating, provided the critical heating rate is observed in said critical temperature range.