Abstract: In an alloy having a Ti/Al ratio close to 52/48, good castability, by virtue of initial solidification in the .beta. phase, together with a sufficiently low density and a good oxidation resistance are obtained by introducing approximately 2 atom. % of rhenium and/or tungsten. These alloys can be used especially for the production of aeronautical turbomachine components.

Abstract: Tantalum-based and niobium-based alloys made up entirely of a crystalline medium exhibiting a substantially continuous centered cubic structure, comprising an intermetallic compound of formula Ti.sub.2 AlMo, and having the following compositions on an atomic basis:______________________________________ Ta + Cr 20 to 35% Cr 0 to 5% Ti 20 to 40% Al 8 to 20% Mo 8 to 20%, ______________________________________wherein the concentration of Ta is less than 30%; and ______________________________________ Nb + Cr 20 to 60% Cr 0 to 5% Ti 20 to 40% Al 8 to 20% Mo 8 to 20%. ______________________________________ .

Abstract: A nickel-based monocrystalline superalloy suitable for turbine engine blades is obtained by adding to the alloy at least one element chosen from erbium and silicon, at a concentration by weight of 50 to 500 ppm for Er and of 500 to 1000 ppm for Si and, optionally, hafnium at a concentration by weight of 500 to 1000 ppm.

Abstract: A nickel-based superalloy suitable for directed solidification, in particular for industrial gas turbine parts, having the following composition by weight:Co: 0 to 5%Cr: 13 to 16%W: 0 to 2%Mo: 2 to 3.5%Al: 3.5 to 4%Ti: 3.5%Ta: 3.

Abstract: A monocrystalline superalloy with a nickel based matrix and particularly intended for the manufacture of turbine blades, has the following composition, by weight: Al=5.4% to 6.2%; Co=4% to 7%; Cr=6% to 9%; Mo=0% to 2.5%; Ta=5.5% to 8%; Ti=O% to 1%; W=7% to 9%; and Ni=balance to 100%.The invention also provides a method of improving the alloy's resistance to creep, in which the Ni.sub.3 Al type .gamma.' phase is put completely into solution at a first temperature, and then the .gamma.' phase is precipitated into the .gamma. solid solution at a temperature greater than 1000.degree. C. This treatment considerably increases the alloy's resistance to creep over a wide range of temperatures.

Abstract: A monocrystalline superalloy with a nickel based matrix and particularly intended for the manufacture of turbine blades, has the following composition, by weight: Al=5.4% to 6.2%; Co=4% to 7%; Cr=6% to 9%; Mo=0% to 2.5%; Ta=5.5% to 8%; Ti=0% to 1%; Wt32 7% to 9%; and Ni=balance to 100%.The invention also provides a method of improving the alloy's resistance to creep, in which the Ni.sub.3 Al type .gamma.' phase is put completely into solution at a first temperature, and then the .gamma.' phase is precipitated into the .gamma. solid solution at a temperature greater than 1000.degree. C. This treatment considerably increases the alloy's resistance to creep over a wide range of temperatures.

Abstract: A low density superalloy having good resistance to oxidation has the following composition by weight:Co: 5.0 to 6.0%W: 4.8 to 5.2%Cr: 7.8 to 8.3%Al: 5.8 to 6.1%Ta: 3.3 to 3.7%Mo: 2.1 to 2.4%Ti: 1.8 to 2.2%B: .ltoreq.10 ppmZr: .ltoreq.50 ppmNi: balance to 100%.

Abstract: A low density superalloy having good resistance to oxidation has the following composition by weight:______________________________________ Co: 5.0 to 6.0% W: 4.8 to 5.2% Cr: 7.8 to 8.3% Al: 5.8 to 6.1% Ta: 3.3 to 3.7% Mo: 2.1 to 2.4% Ti: 1.8 to 2.2% B: .ltoreq.10 ppm Zr: .ltoreq.50 ppm Ni: balance to 100%.

Abstract: A low density nickel based superalloy having good creep characteristics w hot, and intended in particular for making turbomachine parts by monocrystalline solidification, wherein the composition of the alloy in percentages by weight is as follows:______________________________________ Co: 5% to 7% Cr: 5% to 10% Mo: 0.5% to 2.5% W: 3% to 5% Al: 6% to 7.5% Ti: 1.5% to 2.25% Nb: 0% to 0.5% Ta: 2% to 4% V: 0.3% to 0.6% Ni: balance to 100%. ______________________________________Parts, e.g. turbomachine blades, made from the alloy.

Abstract: A monocrystalline alloy with a high resistance to creep having a nickel base matrix, with a density of the order of 8.5 and having a percentage, by weight, composition as follows: Co 5 to 8%--Cr 6.5 to 10%--Mo 0.5 to 2.5%--W 5 to 9%--Ta 6 to 9%--Al 4.5 to 5.8%--Ti 1 to 2%--Nb 0 to 1.5%--C, Zr, and B each less than 100 ppm--Ni remainder to 100%. Furthermore, the summation Ta+Mo+1/2 W lies between 11.5% and 13.5% by weight, the atomic sum Ti+Al+Ta+Nb lies between 15.5% and 17%, the atomic sum Ta+Nb+Mo+1/2 W lies between 4% and 5.5%, the atomic sum Ti+Al+Ta+Nb+Mo+1/2 W lies between 17.5% and 19% and the atomic sum Ti+Al lies between 12.8% and 14.5%.

Abstract: The invention relates to a process for increasing the lifetime of a refrary composite material piece comprising a metallic matrix and a reinforcing phase consisting of aligned monocrystalline fibers made of a metallic carbide, when the piece has suffered a plastic deformation in the direction of said fibers. The invention consists in restoring the initial qualities of the piece by subjecting it to a high temperature, inferior to the melting point of the material, more precisely at the temperature at which the piece resumes its initial length after being cooled at ambient temperature. The invention is particularly applicable to pieces forming turbine blades for aircrafts.

Abstract: A refractory composite material has a nickel-based matrix, containing chromium, hardened by elements such as W in solid solution and hardened by precipitation of a .gamma.'(Ni,Xi).sub.3 (Al,Yi) phase, Xi representing elements different from Ni and Yi elements different from Al which the matrix may contain and which are respectively substituted for Ni and Al atoms in the formation of the .gamma.' precipitate, and with aligned monocrystalline fibers of a transition metal monocarbide, preferably niobium monocarbide, imbedded in said matrix, as obtained by unidirectional solidification. The chromium proportion of the material is maintained at a value lower than that from which the chromium carbide of formula Cr.sub.23 C.sub.6 is formed in the matrix at the expense of the niobium carbide of the reinforcement fibers at the operating temperatures foreseen for the material.

Abstract: A refractory composite material usable in making gas-turbine blades for aviation applications. The composite material comprises a nickel-based superalloy matrix containing cobalt, aluminum in the form of a Ni.sub.3 Al precipitate, and tungsten, and a reinforcing phase of oriented monocrystalline niobium carbide fibers formed in situ during production, by unidirectional solidification. The composition of the composite material by weight expressed in percent is:Co -- 20-30%Cr -- 6-15%W -- 7-10%Al -- 3-6%Nb -- 4-6%C -- 0.4-0.65%Ni balance to 100.

Abstract: Composite materials which comprise a matrix of a complex refractory superoy and embedded in said matrix filiform particles of carbide and, in the matrix, a fine precipitation of carbide of the same nature as the one of the filiform particles.