Alcan International Limited

Gary Hay

Don Allen Doutre

Peter Alexander Wales

Iljoon Jin

David James Lloyd

Richard S Bruski

A metallic alloy having a semi-solid range between the liquidus temperature and the solidus temperature of the metallic alloy is processed by cooling the metallic alloy from an initial metallic alloy elevated temperature to a semi-solid temperature of less than the liquidus temperature and more than the solidus temperature, and maintaining the metallic alloy at the semi-solid temperature for a sufficient time to produce a semi-solid structure in the metallic alloy of a globular solid phase dispersed in a liquid phase. The cooling may be accomplished by providing a crucible at a crucible initial temperature below the solidus temperature, pouring the metallic alloy into the crucible, and allowing the metallic alloy and the crucible to reach a thermal equilibrium between the liquidus temperature and the solidus temperature of the metallic alloy. The method further includes removing at least some, but not all, of the liquid phase present in the semi-solid structure of the metallic alloy to form a solid-enriched semi-solid structure of the metallic alloy, and forming the metallic alloy having the solid-enriched semi-solid structure into a shape.

Semi-solid concentration processing of metallic alloys

A composite material having less than about 25 volume percent refractory particles in a metal matrix is concentrated to have about 37-45 volume percent refractory particles. The concentrating is accomplished by heating the composite material to melt the matrix, and then contacting the molten composite material to a porous element having an average pore size greater than that of the average particle size. A small pressure differential, on the order of about one atmosphere, is applied across the porous element, so that metal matrix material separates from the composite material and flows through the porous element. The particulate volume fraction in the composite material gradually increases. When the particulate volume fraction exceeds about 37 volume percent, the mass of composite material becomes semi-solid and freestanding. The resulting composite material may be further processed, as by forming to a useful shape or diluting with another matrix material.

Preparation of metal-matrix composite materials with high particulate loadings by concentration

A composite material is rapidly melted by furnishing a pre-wetted composite material in the form of granules, placing the granules into an induction coil, and powering the induction heater to melt the metal matrix portion of the granules to form a molten mixture. High power inputs to the induction coil may be used, so that the granules are rapidly heated to their melting point and to temperatures above the melting point, from which the molten mixture may be cast. Because of the rapid heating, otherwise-reactive composite materials may be prepared by melting in air.

Rapid induction melting of metal-matrix composite materials

A device for measuring metal purity, comprising a receptacle for holding a sample of molten metal, the receptacle being made, at least internally, from an insulating refractory material and having a bottom wall provided with a hole containing a filter element. The bottom wall is substantially impermeable to air except at the hold. An enclosed collection vessel is positioned below the receptacle for collecting molten metal which passes through the filter element from the receptacle, the collection vessel having an opening permitting extraction of gas from within the vessel to enable a vacuum to be generated within the vessel during use of the device. A leak-tight seal is established between the receptacle for molten metal and the collection vessel to permit vacuum generated in the collection vessel to draw molten metal into the collection vessel from the receptacle through the filter. The receptacle for molten metal has a heat diffusivity value that is sufficiently low that, in use, the temperature of the molten metal in the receptacle does not fall below the liquidus temperature in a period of time required for the vacuum to draw a fixed amount of molten metal sufficient for metal purity testing purposes through the filter and into the collection vessel from the receptacle. The invention also relates to a corresponding method, and to novel parts of the device.

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Gary Hay