Abstract: A calcined microsphere of ultrafine bauxite particles having a mean particle size in the range 0.01 to 0.3 micrometers, said microsphere having a particle size less than 30 micrometers and being characterized by a substantially solid form having a pycnometric density substantially falling in the range 3.2-3.0 g/cm.sup.3, a BET surface area substantially falling in the range 0.05 to 0.5 m.sup.2 /g and a crystal grain size less than 4 micrometers, the surface chemistry of the microsphere being modified to enhance the wettability of the microsphere and to improve its ability to bond strongly with matrix materials in use.

Abstract: A calcined microsphere of ultrafine bauxite particles having a mean particle size in the range 0.01 to 0.3 micrometers, said microsphere having a particle size less than 30 micrometers and being characterized by a substantially solid form having a pycnometric density substantially falling in the range 3.2-3.9 g/cm.sup.3, a BET surface area substantially falling in the range 0.05 to 0.5 m.sup.2 /g and a crystal grain size less than 4 micrometers, the surface chemistry of the microsphere being modified to enhance the wettability of the microsphere and to improve its ability to bond strongly with matrix materials in use.

Abstract: A green pressed article of high strength and of low relative density, formed from a heat-resistant aluminum alloy of the Al/Fe/X or Al/Cr/X type, where X is Ti, Ce, Zr, Hf, V, Nb, Cr, Mo or W, is produced by a powder-metallurgical process, wherein an alloy melt is atomized to form fine particles by means of an inert gas jet, with which 0.5 to 2% by volume of oxygen is admixed, and the powder produced in this manner is compacted. Nitrogen, argon or helium can be employed as inert gas. The green pressed article is preferably formed from a small proportion of coarser, non-spherical particles and a greater proportion of finer, spherical particles.

Abstract: An aluminum alloy for the production of powders having increased high-temperature strength by rapid quenching, the said alloy containing 1.5 to 5% by weight of Li, 4 to 11% by weight of Fe and 1 to 6% by weight of at least one of the elements Mo, V or Zr, the remainder being Al, or 1.5 to 5% by weight of Li, 4 to 7% by weight of Cr and 1 to 4% by weight of at least one of the elements V or Mn, the remainder being Al. A low density and good high-temperature strength as well as good thermal stability up to 400.degree. C. coupled with Vickers hardnesses of up to 180 (HV) are achieved. Hardness-imparting dispersoids in the form of the phases Al.sub.3 Li and Al.sub.3 Zr, as well as other intermetallic compounds of Al with Mo, V or Mn, having a particle diameter of no more than 0.1 .mu.m, constitute a large volume fraction.

Abstract: A green pressed article of high strength and of low relative density, formed from a heat-resistant aluminum alloy of the Al/Fe/X or Al/Cr/X type, where X is Ti, Ce, Zr, Hf, V, Nb, Cr, Mo or W, is produced by a powder-metallurgical process, wherein an alloy melt is atomized to form fine particles by means of an inert gas jet, with which 0.5 to 2% by volume of oxygen is admixed, and the powder produced in this manner is compactd. Nitrogen, argon or helium can be employed as inert gas. The green pressed article is preferably formed from a small proportion of coarser, non-spherical particles and a greater proportion of finer, spherical particles.

Abstract: A workpiece consisting of a heat-resistant aluminum alloy is produced by a powder-metallurgical process wherein an alloy containing 8 to 14% by weight Fe, 0.5 to 2% by weight V and 0.2 to 1% by weight Mn is melted, the melt is cooled in a gas stream at a rate of at least 10.sup.5 .degree.C/s and is atomized to form particles having a diameter of 1 to 40 .mu.m, whereupon the powder is consolidated a temperature of 350.degree. to 450.degree. C. at a pressure of 2000 to 6000 bar, to form a pressed article. In this process, the intermetallic compound Al.sub.6 Fe stabilized by Mn occurs in fine distribution. This dispersoid imparts high ductility and toughness to the grain.

Abstract: Aluminum alloy, suitable for rapid quenching from a melt supersaturated with alloy components, which contains 2 to 5.5% by weight of Cr and 2 to 5.5% by weight of V, the remainder being Al, and may contain further added amounts of Mo, Zr, Ti or Fe, individually or in combination, up to a total content of not more than 1% by weight, the total content of all alloy elements being no more than 10% by weight. The simultaneous occurrence of the phases Al.sub.13 Cr.sub.2 and Al.sub.10 V in silid solution and as hardness-imparting dispersoids having a particle diameter of not more than 0.1 .mu.m results in good high-temperature strength and thermal stability coupled with good ductility and toughness of the material. The comparatively Low Vickers hardness of, on average, only about 130 (HV) for the rapidly solidified alloys initially obtained make the powders readily processable. After the heat treatment, the Vickers hardness of the workpiece reaches values up to about 200 (HV).