Abstract: Engine block cylinder liners are formed from high melting temperature aluminum alloy composites. A cast composite is first formed from a high melting temperature aluminum alloy, e.g. Al-Mn, Al-Cr, Al-Ni, Al-Fe or Al-Cr-Zr, and refractory particles, e.g. alumina. This composite is then extruded into a tubular sleeve. If desired, a long tube may be extruded which is then cut into desired lengths. These new cylinder liners have the following desirable properties: high melting temperature, good strength at the service temperature, higher thermal conductivity than cast iron, good wear resistance and good corrosion resistance.

Abstract: A method for preparing a composite material comprises the steps of providing a first mixture of a molten aluminum-base matrix alloy having at least about 4 percent by weight magnesium, and a mass of discontinuous reinforcing particles that are not soluble in the molten matrix alloy, and mixing the first mixture to wet the matrix alloy to the particles and to distribute the particles throughout the volume of the molten matrix alloy. The first matrix alloy is diluted to reduce the magnesium content of the mixture to less than about 4 percent by weight magnesium, to produce a second mixture, and the second mixture is cast. The second mixture has at least about 5 volume percent particles, and preferably has about 5-25 volume percent particles.

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 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. A novel foamed metal product is also described.

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.

Abstract: A new family of medium and high strength, thermally stable aluminum based alloys are described having the following composition: 0.4 to 1.2% by weight chromium, 0.3 to 0.8% by weight zirconium, 1.5 to 2.5% by weight manganese, 0 to 2.0% by weight magnesium and the balance essentially aluminum. These alloys can be produced on a twin-roll caster preferably at a thickness of no more than 4 mm and a casting temperature of at least 820.degree. C.