Office National D'etudes Et De Recherches Aerospatiales (Onera)

Onera (Office National D'etudes Et De Recherches Aerospatiales)

Herve Bibring

Maurice Rabinovitch

Tasadduq Khan

Jean-Francois Stohr

Jean-Pierre Trottier

Jean-Michel Hauser

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.

Multi-phase metallic systems of the .gamma.,.gamma.', NBC type with

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:

Metal-refractory composite material

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.

Process for the improvement of refractory composite materials comprising

A mold for obtaining metallic parts with an orientated crystalline struct by the directed solidification of an alloy is disclosed. The mould comprises a body of refractory mold that is a good heat conductor and on the inner wall of said body is provided a chemically protective lining of dense refractory metal oxide, with a high degree of purity, deposited on said body by blowpipe projection as a thin non-porous layer. The thickness of the metal oxide lining is in the order of a tenth of a millimeter to five tenths of a millimeter, the oxide being choosen in the group constituted by aluminium oxide, zirconium oxide, magnesium oxide and thorium dioxide with a degree of purity at least equal to 99.5 %.

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Meudon, France

Herve Bibring