Abstract:
A continuous cast aluminum alloy strip is used in the production of thin gauge or converter foils. The alloy strip contains 0.4 to 0.8% by weigth Fe and 0.2 to 0.4% by weight Si, has an an cast thickness of less than about 30 mm and contains a substantially single intermetallic species of alpha-phase. The strip is cast using a continuous strip caster, e.g. a block or belt caster.
Abstract:
An aluminum alloy strip useful for can stock having a thickness of less than or equal to about 30 mm, and containing large (Mn,Fe)Al.sub.6 intermetallics as principal intermetallic particles in said strip. The intermetallic particles have an average surface size at a surface of the strip and an average bulk size in a bulk of the strip, the average surface size being greater than the average bulk size. The strip article may be produced by supplying a molten aluminum alloy having a composition consisting, in addition to aluminum, essentially by weight of: Si between 0.05 and 0.15%; Fe between 0.3 and 0.6%; Mn between 0.6 and 1.2%; Mg between 1.1 and 1.8%; Cu between 0.2 and 0.6%; and other elements: less than or equal to 0.05% each element with a maximum of 0.2% for the total of other elements; and casting the molten alloy in a continuous caster having opposed moving mold surfaces to an as-cast thickness of less than or equal to 30 mm. The moving mold surfaces have a surface roughness of between 4 and 13 microns, substantially in the form of sharp peaks, and heat flux is extracted from the metal at a rate that results in the production of an interdendritic arm spacing of between 12 and 18 microns at the surface of said strip. The strip may then be processed to final thickness by means of rolling and annealing steps.
Abstract:
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.
Abstract:
A novel lightweight gas metal composite is produced having isolated particle stabilized pores. A composite of a metal matrix, e.g. aluminum, and finely divided solid stabilizer particles, e.g. silicon carbide, is heated above the liquidus temperature of the metal matrix and this is mixed such that a vortex is formed. The molten composite is blanketed with a gas and during the vortex mixing. This gas is drawn into the melt to produce an expanded, viscous molten composite material containing pores which are very small, spherical-shaped and quite evenly distributed. The viscous molten composite material can be directly formed into a solid shaped product and is also capable of being remelted and formed by forming processes without destroying the integrity of the pores. The result is a lightweight expanded metal product capable of being formed into shapes to close dimensional tolerances.
Abstract:
A metal matrix composite material containing discontinuous particles in a metallic matrix is prepared by forming a mixture of the molten alloy and the particles in a closed reactor, removing oxygen from the interior of the reactor, statically pressurizing the interior of the reactor with nitrogen gas, mixing the mixture of the molten alloy and particles in the presence of the static nitrogen gas to wet the molten matrix to the particles, and evacuating the interior of the reactor in a stepwise manner. The nitrogen gas aids in wetting the metallic alloy to the particles by forming aluminum nitride at the particle-molten matrix interface, so that a lower contact angle of the alloy to the particle results. Oxygen that may be present in the sealed reactor is gettered by the aluminum, and the nitrogen is removed by stepwise evacuation, thereby minimizing the introduction of gas into, and retention of gas within, the melt.
Abstract:
A method is described for producing foamed metal in which gaseous bubbles are retained within a mass of molten metal during foaming. The method comprises heating a composite of a metal matrix and finely divided solid stabilizer particles above the liquidus temperature of the metal matrix, discharging gas bubbles into the molten metal composite below the surface thereof to thereby form a foamed melt on the surface of the molten metal composite and cooling the foamed melt thus formed below the solidus temperature of the melt to form a solid foamed metal having a plurality of closed cells.