Abstract: 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.

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 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.

Abstract: A method of manufacturing a mold adapted to be used for casting bodies of fiber-reinforced composites. A model of the body to be cast is prepared and coated with a one-piece dense shell of refractory metallic oxide deposited by plasma or flame spraying and the model is then separated from the shell by conventional physical or chemical treatment.

Abstract: Disclosed are a method and apparatus for molding articles in which a highly planar solidification front is desired. A charge of liquefied alloy to be molded into the desired article is placed in a mold and submerged in a heat-exchange bath of liquid metal forming a cylindrical column which is heated in an upper portion and cooled in a lower portion to define an intermediate level at which the bath temperature corresponds to the melting point of the alloy. Upon a progressive lowering of the mold within the bath, a solidification front formed in the alloy at that intermediate level advances from the bottom to the top of the charge.

Abstract: A method of manufacturing a mold adapted to be used for casting bodies of ber-reinforced composites. A model of the body to be cast is prepared and coated with a one piece dense shell of refractory metallic oxide deposited by plasma or flame spraying and the model is then separated from the shell by conventional physical or chemical treatment.

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.

Abstract: 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 %.