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

Office National D'etudes Et De Recherches Aerospatiales

Jean-Michel Hauser

Maurice Rabinovitch

Fernand Pautonnier

Tasadduq Khan

Herve Bibring

Jean-Francois Stohr

A method and apparatus for manufacturing bars made of an alloy by unidirectional solidification. The mold is moved relative to a hot source and a cold source disposed below the hot source. The relative positions of the two sources as well as their efficiency and the displacement speed of the mold are set so that there is established within the alloy contained in the mold a planar solidification front with a high thermal gradient at the level of the front, and so that there is produced an orientation of the structure of the alloy which is perpendicular to the solidification front. During the whole duration of the solidification, the mold is fed with alloy powder having the required nominal composition at the rate corresponding to the quantity of alloy solidified per unit of time.

Bars of metallic composite material made by unidirectional solidification

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 method and apparatus for manufacturing bars made of an alloy by unidireonal solidification. The mold is moved relative to a hot source and a cold source disposed below the hot source. The relative positions of the two sources as well as their efficiency and the displacement speed of the mold are set so that there is established within the alloy contained in the mold a planar solidification front with a high thermal gradient at the level of the front, and so that there is produced an orientation of the structure of the alloy which is perpendicular to the solidification front. During the whole duration of the solidification, the mold is fed with alloy powder having the required nominal composition at the rate corresponding to the quantity of alloy solidified per unit of time.

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Meudon, France

Jean-Michel Hauser