Abstract: Methods for making a tribological bearing wear surface for a compressor component are provided. Such methods involve semi-solid metal casting, where an admixture of solid lubricant particles and a metal alloy material is heated to melt the metal alloy material, while the lubricant particles remain in a solid phase. The alloy material and solid lubricant have substantially different densities. The metal alloy material may be a copper, iron, or aluminum alloy, for example. The method further comprises mixing and cooling the admixture to form a semi-solid slurry admixture. Next, the method comprises introducing the semi-solid slurry admixture into a die. Finally, the semi-solid slurry admixture in the die is solidified to form a solid component having the solid lubricant particles homogenously distributed within a metal alloy material matrix, thus forming a metal matrix composite. Compressor components made from such methods are also provided.

Abstract: Methods for making a tribological bearing wear surface for a compressor component are provided. Such methods involve semi-solid metal casting, where an admixture of solid lubricant particles and a metal alloy material is heated to melt the metal alloy material, while the lubricant particles remain in a solid phase. The alloy material and solid lubricant have substantially different densities. The metal alloy material may be a copper, iron, or aluminum alloy, for example. The method further comprises mixing and cooling the admixture to form a semi-solid slurry admixture. Next, the method comprises introducing the semi-solid slurry admixture into a die. Finally, the semi-solid slurry admixture in the die is solidified to form a solid component having the solid lubricant particles homogenously distributed within a metal alloy material matrix, thus forming a metal matrix composite. Compressor components made from such methods are also provided.

Abstract: The present invention provides a method and apparatus for die-casting copper and other metals that are cost-effective and practical for production use in die-casting, for example, copper motor rotors. In motor rotors, the incorporation of die-cast copper for conductor bars and end rings in place of aluminum is known to result in improvements in motor energy efficiency. Previous attempts to die-cast copper motor rotors in a commercially feasible manner have failed because copper's high melting point places too great a stress on the die material, resulting in cracking and fracturing of the molds. High temperature die materials such as nickel, tungsten and molybdenum based alloys with a high melting point are employed, and a die casting apparatus is provided to pre-heat the molds prior to injection of the molten copper. Pre-heating and high operating temperatures provide extended die life.

Abstract: The present invention provides a method and apparatus for die-casting copper and other metals that are cost-effective and practical for production use in die-casting, for example, copper motor rotors. In motor rotors, the incorporation of die-cast copper for conductor bars and end rings in place of aluminum is known to result in improvements in motor energy efficiency. Previous attempts to die-cast copper motor rotors in a commercially feasible manner have failed because copper's high melting point places too great a stress on the die material, resulting in cracking and fracturing of the molds. High temperature die materials such as nickel, tungsten and molybdenum based alloys with a high melting point are employed, and a die casting apparatus is provided to pre-heat the molds prior to injection of the molten copper. Pre-heating and high operating temperatures provide extended die life.

Abstract: Metallic bodies are heated up to a predetermined temperature between the solidus and the liquidus to produce a semisolid state by supplying the metallic bodies with different amounts of energy over time. The metallic bodies are initially heated with a higher amount of energy, whereafter the supply of energy is lowered. Varying amounts of energy may also be employed to control the desired temperature as a function of shaping pressure or cycle time of the shaping machine.

Abstract: Information packets are routed among a constellation of satellite nodes in a communication system in a distributed, yet systematic fashion. Routing tables for each node are generated in advance by a recursive process that considers link usage and anticipated link loading for different times and states of the constellation. Routing tables are generated centrally, distributed to, and maintained in each satellite node. The routing tables are updated regularly to reflect anticipated traffic loading and physical changes in node connectivity within the constellation which occur as a result of satellite motion. The tables are also updated responsively to reflect changes in network connectivity which occur because of failures that may occur in the cross-links or satellite nodes.

Abstract: Shaped metal parts are produced on a continuous basis from a semi-solid metal perform. A plurality of free-standing metal slugs are sequentially heated within an arcuate path defined by a pair of concentrically-positioned solenoid coils to a semi-solid state, such that they may be shaped into a metal part. Means for rotating the slugs during their movement through the arcuate path is also provided.

Abstract: A method and apparatus for rheocasting (slurry casting) molten metal employ a stirring chamber located upstream of a casting mold. Electromagnetic stirring is employed in both the stirring chamber and the casting mold. Structure is provided for minimizing secondary recirculating flows in the molten metal as it flows downstream through the apparatus, for preventing hangers and for eliminating the columnar dendritic zone at the periphery of the casting. The efficiency of utilization of the magnetic field is optimized as is the agitation required for producing a desired fine, spheroidal, degenerate dendritic grain structure in the solidified casting.

Abstract: Shaped metal parts are produced on a continuous basis from semi-solid metal preforms. Plurality of cans, each containing a metal preform, are sequentially heated in an induction heating zone to bring the preforms to a semi-solid level. The preforms can be transformed without loss of any metal or heat to a press where they are shaped in a semi-solid state into a metal part. The can can then be removed and recycled.

Abstract: A process and apparatus is described for slurry casting an ingot having a non-dendritic structure across substantially its entire cross section. The casting mold has a first chamber for extracting heat from the molten material. The amount of heat extracted from the molten material and the cooling rate of the molten material is controlled to initiate growth of primary phase particles and to form a semi-solid slurry having a desired fraction solid. The mold also has a second chamber for casting the slurry into an ingot. Adjacent the exit portion of the first chamber and the inlet portion of the second chamber, a transition member is provided for delivering the slurry to the casting chamber and for preventing the ingot shell from extending back into the first chamber.

Abstract: An apparatus and process for producing shaped metal parts of a semi-solid metal slurry. The metal slurry is introduced as a preform slug or ingot to a prechamber which is subjected to sufficient pressure to force a portion of the semi-solid metal slurry from the prechamber to a metal part shaping die cavity. The completed metal part, together with the portion of metal which remained in the prechamber during part formation, is removed and the metal which remained in the prechamber is detached from the final metal part.

Abstract: A process for preparing a slurry structured metal composition comprising degenerate dendritic solid particles contained within a lower melting matrix composition, the process comprising vigorously agitating at a given shear rate molten metal as it is solidified. Greatly improved processing efficiencies result if the shear and solidification rates are adjusted so that the ratio of the shear rate to the solidification rate is maintained at a value ranging from 2.times.10.sup.3 to 8.times.10.sup.3.

Abstract: A process and apparatus for the continuous production of shaped aluminum alloy-particulate composites. The process comprises metering at a substantially constant ratio a particulate solid molten aluminum alloy containing at least 0.10% by weight of magnesium into a mixing station while continuously vigorously agitating to produce a homogeneous mixture, simultaneously discharging from the mixing station a homogeneous mixture of molten aluminum alloy and particulate solid, transferring the mixture to a forming station and shaping and solidifying the composite.

Abstract: A process and apparatus for providing metal material having an improved structure for forming into a desired article is disclosed herein. The improved structure is obtained by slurry casting a material into a continuous member and then hot working the slurry cast material. Upon reheating to a semi-solid state, the hot worked, slurry cast material will exhibit finer particles and fewer eutectic melting rosettes than would be exhibited by the slurry as-cast material in an unworked and heated condition. The hot working of the slurry cast material produces an article having a deformed structure exhibiting directionality.

Abstract: A process and apparatus is described for slurry casting an ingot having a non-dendritic structure across substantially its entire cross section. The casting mold has a first chamber for extracting heat from the molten material. The amount of heat extracted from the molten material and the cooling rate of the molten material is controlled to initiate growth of primary phase particles and to form a semi-solid slurry having a desired fraction solid. The mold also has a second chamber for casting the slurry into an ingot. Adjacent the exit portion of the first chamber and the inlet portion of the second chamber, a transition member is provided for delivering the slurry to the casting chamber and for preventing the ingot shell from extending back into the first chamber.

Abstract: A process and apparatus for the continuous production of shaped aluminum alloy-particulate composites. The process comprises metering at a substantially constant ratio a particulate solid molten aluminum alloy containing at least 0.10% by weight of magnesium into a mixing station while continuously vigorously agitating to produce a homogeneous mixture, simultaneously discharging from the mixing station a homogeneous mixture of molten aluminum alloy and particulate solid, transferring the mixture to a forming station and shaping and solidifying the composite.

Abstract: A fine grained metal composition suitable for forming in a partially solid, partially liquid condition. The composition is prepared by producing a solid metal composition having an essentially directional grain structure and heating the directional grain composition to a temperature above the solidus and below the liquidus to produce a partially solid, partially liquid mixture containing at least 0.05 volume fraction liquid. The composition, prior to heating, has a strain level introduced such that upon heating, the mixture comprises uniform discrete spheroidal particles contained within a lower melting matrix. The heated alloy is then solidified while in a partially solid, partially liquid condition, the solidified composition having a uniform, fine grained microstructure.

Abstract: Die castings are made from metal compositions that are fully liquid or as a preferred embodiment contain between about 10 and 85 weight percent degenerate dendrites. The composition is injected into the cavity of a die at a mean die temperature which is as near to ambient temperature as possible and usually less than about 400.degree. F. The die is formed of a material having a thermal diffusivity of at least about 0.5 cm.sup.2 /sec. The castings are ejected and the die surface is sprayed with a liquid to bring the die surface temperature back to the mean die temperature or below in the shortest possible time. The time between injection and ejection is less than about 1 minute and the time between ejection and spraying is less than about 30 seconds.

Abstract: A process for forming metal compositions containing in situ composites. A metal composition is heated to a liquid and then solidified by being directed into a cooling zone. The metal in the small volume at or near the liquid-solid interface is heated to achieve a high temperature gradient between the solid and liquid metal while not exceeding an average temperature in the liquid which degrades the container for the liquid metal. The metal fed into the small volume can be either a liquid or a solid.

Abstract: A process for forming metal compositions containing cellular in situ composites. A metal composition containing at least 25 volume percent liquid is cooled to produce aligned columnar dendrite growth. The resultant composition then is subjected to isothermal coarsening in the semi-solid temperature range to form the cellular in situ composites. This composition then is solidified. The metal compositions are particularly useful in rotating machinery.