Alcan International Limited

Limca Research Inc.

Novelis, Inc.

Don Allen Doutre

Peter Alexander Wales

Gary Hay

Ghyslain Dube

Iljoon Jin

David James Lloyd

Jean-Pierre Martin

Roderick I Guthrie

Kevin Michael Gatenby

Edward S Luce

Richard S Bruski

Gaston Riverin

Jean-Yves Fortin

Xiao-Guang Chen

Eric Lees

Jeff Ballyns

Gijsbertus Langelaan

Uta Harnisch

Jacques Sheehy

Camil Jean

Paul Brisson

A cast composite material is prepared by furnishing an aluminum-based matrix alloy and forming a mixture of free-flowing boron carbide particles and the aluminum-based matrix alloy in molten form which is stirred to wet the matrix alloy to the boron carbide particles and to distribute the particles throughout the volume of the melt. The molten mixture is then cast. The fluidity of the molten mixture is maintained by (a) maintaining the magnesium content of the matrix metal below about 0.2% by weight, or (b) starting with a matrix metal containing less than 0.2% by weight magnesium and adding further magnesium to the mixture a short time before casting, or (c) having at least 0.2% by weight titanium present in the mixture.

Aluminum alloy-boron carbide composite material

A method of producing a clad metal ingot suitable for rolling to form a clad metal sheet, and the clad metal ingot so produced. The method involves providing a solid core ingot having an upper side with a rolling face thereon having cavities extending inwardly into the ingot from the rolling face. All or all-but-one of the cavities are blocked against molten metal entry and casting cores extending outwardly from the rolling surface are provided in alignment with the cavities. Molten cladding metal is cast on the rolling face around the casting cores to produce a composite ingot and the casting cores are removed to produce voids in the cladding layer, and the cavities are unblocked. The resulting interconnected cavities and voids are filled with a molten metal to form cast-in-place metal lugs keying or pinning the cladding layer to the core ingot.

Method of producing clad metal products

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 metal-matrix composite material includes a matrix having magnesium in an amount of more than about 0.3 weight percent but no more than about 2.5 weight percent, an alloying element of about 0.8 to about 2.5 weight percent iron or from about 1.0 to about 2.5 weight percent manganese, and the balance aluminum and impurities. Dispersed throughout the matrix is a plurality of metal oxide particles present in an amount of more than about 5 volume percent but no more than about 25 volume percent of the total volume of the matrix and the particles. This material may be cast into casting molds. After casting is complete and during solidification of the matrix alloy, a high volume fraction of intermetallic particles is crystallized in the matrix alloy. The total of the volume fractions of the metal oxide particles and the intermetallic particles is from about 10 to about 40 volume percent, preferably from about 25 to about 40 volume percent.

Cast metal-matrix composite material and its use

A method and apparatus for detecting and measuring suspended solid particles in a molten metal, even if the metal also contains liquid and/or gaseous inclusions. The method involves moving molten metal through an orifice of predetermined hydrodynamic diameter provided in an electrically non-conductive barrier. As the molten metal is moved through the orifice, a current path is established by passing a current through the orifice from electrodes positioned on opposite sides of the barrier. Changes in voltage of the current are measured as the metal is drawn through the orifice, and the number of particles suspended in said metal drawn through the orifice is detected from the voltage changes. The metal, immediately before being moved through the orifice, is conveyed through a passage defined by an electrically non-conductive surface positioned in the current path, the passage including a region having a hydrodynamic diameter of between 2 and 10 times the hydrodynamic diameter of the orifice, at least a part of the region being of substantially constant hydrodynamic diameter. The provision of the passage upstream of the orifice has the effect of removing substantially all liquid and gaseous inclusions from the molten metal before the metal passes through the orifice.

Method and apparatus for the detection and measurement of solid

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.

Portable liquid metal filtration device for inclusion analysis

The invention provides a new method for the determination of the concentration of gas dissolved in a molten metal or metal matrix composite employing a new immersion head probe in apparatus employing the method. Such determinations are needed to facilitate removal of the gas, which can cause loss of desirable properties and/or bubbles in the solidified material and subsequent processing difficulties. This determination is particularly difficult with metals containing high concentrations of particulate additions, such as metal matrix composites, since it is necessary to avoid deposition of the particulates and consequent inaccurate readings. The method employs apparatus which circulates an inert carrier gas through the probe in gas exchange contact with the molten metal to entrain dissolved gas until an equilibrium mixture is obtained; the concentration of the dissolved gas in the mixture then is representative of its concentration in the molten metal. The head consists of a monolithic or integral body of a porous gas-permeable material of sufficient porosity, pore size and permeability to permit the necessary gas diffusion in a reasonable period of time. If the test is to be carried out in a stationary body of molten metal, the probe may be vibrated or the metal may be stirred.

Method and apparatus for the determination of gas concentration in

Apparatus and method for studying particles suspended in an electrically conducting fluid by providing an aperture with a current path therethrough, causing the fluid to flow through the aperture and detecting resistive pulses caused by the passage of suspended particles. Additional information about particle size is generated by designing the aperture such that its cross-section changes progressively along its length, and observing the duration of the resistive pulses, which duration varies with particle size. The method is particularly useful for the study of particles suspended in molten metal.

Apparatus for studying particles having an aperture whose

The invention provides a new immersion head probe for use in apparatus for the determination of the concentration of gas dissolved in a molten metal. Such determinations are needed to facilitate removal of the gas, which can cause bubbles in the solidified metal and subsequent processing difficulties. The apparatus circulates an inert carrier gas through the probe in gas exchange contact with the molten metal to entrain dissolved gas until an equilibrium mixture is obtained; the concentration of the dissolved gas in the mixture then is representative of its concentration in the molten metal. The head consists of a monolithic or integral body of a porous gas-permeable material of sufficient mechanical strength at the temperature of the molten metal and of sufficient porosity, pore size and permeability to permit the necessary gas diffusion in a reasonable period of time. The body of the probe preferably is thin in one direction to minimize the path length for the gas to diffuse therein, and is provided with a carrier gas inlet and outlet suitably spaced apart to ensure that the gas diffuses throughout the body. If the test is to be carried out in a stationary body of molten metal, the probe may be vibrated or the metal may be stirred to increase the probe/metal contact, both decreasing the time required for the gas mixture to reach sufficient equilibrium.

Probe for the determination of gas concentration in molten metal

The invention provides a new method and apparatus for the detection of non-conductive particulates in molten metals, such as aluminum, gallium, zinc and lead, that can be liquified and drawn into a suitable refractory container. The passage into the container is of very small diameter (about 300 micrometers for aluminum) and it forms part of a current path between two electrodes carrying a current of about 1 to 500 amperes. The path is surrounded by liquid metal which forms an effective Faraday cage screening the path, enabling the passage of a particulate of about 15 micrometers or larger to produce a voltage pulse between the electrodes of greater than 5 microvolts, which is detectable above the inevitable background noise, which is of about that value. The size of the pulse gives an indication of the particle size and appropriate measurement and sampling electronically of the pulses gives a rapid evaluation (less than 3 minutes) of the particle size distribution, giving the operator an opportunity of deciding immediately whether or not further cleansing of the metal is required.

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Kingston, Canada

Don Allen Doutre