EP0024984B1 - Process of making titanium alloy articles by powder metallurgy - Google Patents

Process of making titanium alloy articles by powder metallurgy Download PDF

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Publication number
EP0024984B1
EP0024984B1 EP80401206A EP80401206A EP0024984B1 EP 0024984 B1 EP0024984 B1 EP 0024984B1 EP 80401206 A EP80401206 A EP 80401206A EP 80401206 A EP80401206 A EP 80401206A EP 0024984 B1 EP0024984 B1 EP 0024984B1
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Prior art keywords
powder
titanium
process according
titanium alloy
temperature
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German (de)
French (fr)
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EP0024984A1 (en
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Pierre Blum
Jacques Devillard
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/17—Metallic particles coated with metal

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  • the present invention relates to a process for manufacturing titanium-based alloy parts by powder metallurgy.
  • titanium exhibits an allotropic transformation at a temperature of 882 ° C; this temperature thus defines the stability domain of two phases: phase a of compact hexagonal structure which is stable below 882 ° C and the centered cubic ⁇ phase which appears above 882 ° C.
  • the methods for manufacturing titanium parts using sintering techniques generally consist in carrying out isostatic hot sintering under a pressure of 1 to 1.5 ⁇ 10 2 MPa, for 4 h, ie at a temperature of approximately 950 ° C. when one wants to maintain phase a in the case of pure titanium or when one wants to obtain the structure ⁇ + ⁇ in the case of titanium alloys, that is to say at a temperature of approximately 1050 ° C. when one wants to be located in the temperature range which corresponds to the ⁇ phase of pure titanium or its alloys.
  • parts made of titanium or of titanium alloys can be produced by conventional sintering processes, at pressures below 50 MPa and at temperatures below 900 ° C., starting from titanium powders or titanium alloys. , wrought and ground, but in this case the parts obtained are fragile due to significant intergranular oxygen contamination.
  • these sintering techniques do not allow parts of complex shape to be obtained directly, such as turbine blades with integrated blades, in particular having a "collar” structure, that is to say a heterogeneous structure characterized by the presence of large grains surrounded and welded together by finely crystallized grains.
  • the present invention specifically relates to a process for manufacturing titanium-based alloy parts by powder metallurgy, which overcomes the drawbacks of the aforementioned processes and which also makes it possible to obtain titanium alloy parts having the structure "in necklace ”.
  • the method as characterized above advantageously takes advantage of the fact that by locally modifying by coating with a suitable material such as copper, the surface composition of the particles of titanium powder or of titanium alloy, it is possible to during the sintering, an interstitial liquid phase appears on the surface of the powder grains and thus facilitate local deformations, which makes it possible to carry out the sintering at temperatures and pressures lower than those usually necessary for sintering powders having a particle size from 100 to 1000 ⁇ m.
  • the coating material which, in the case of copper, generally represents from 1 to 5% by weight, affects only the cortical zone of the grains without profoundly modifying the composition of the alloy . Also, during heating, the compression exerted during the temperature rise, that is to say when the coating material is still present on the surface of the grains, makes it possible to obtain a local deformation of the latter and their densification.
  • the coating material can be constituted by a titanium compound fusible at temperature T 1 , or preferably, by a material comprising an element capable of combining with the titanium of the powder to form a compound, by example a eutectic, fuse at temperature T 1 .
  • the coating may consist of this element or also of a compound or an alloy of this element.
  • the element used to form the coating is a betagen element such as iron, copper or nickel.
  • a betagen element such as iron, copper or nickel.
  • copper is used.
  • the sintering kinetics can be improved by locally modifying the phases of the alloy during densification.
  • titanium alloys of the TA 6 V type that is to say alloys comprising 90% of titanium, 6% of aluminum and 4% of vanadium, without addition of a betagenic element such as copper
  • a betagenic element such as copper
  • this two-phase structure ⁇ + ⁇ has a significant resistance to deformation, which does not promote densification.
  • a betagen element such as copper
  • the betagen element has a tendency to diffuse towards the center of the grains. Also, to obtain locally on the surface of the grains this single-phase structure ⁇ which promotes sintering, it is advantageous to carry out the heating and the application of the pressure quickly enough to avoid excessive diffusion. important of the betagen element and locally obtain a sufficient concentration of this element.
  • the powder is heated to the sintering temperature at a vi tesse of about 500 ° C / h to 1000 ° C / h.
  • the method of the invention has the advantage of leading to the production of titanium alloy parts having improved mechanical properties. Indeed, the fact of carrying out sintering in.
  • the fineness of the precipitation a depends in particular on the speed at which the parts obtained are cooled.
  • the powder of titanium or of titanium alloy having a particle size of 100 to 1000 ⁇ m, is prepared by the technique of fusion centrifugation.
  • this technique consists in bringing the end surface of a cylindrical ingot of titanium or titanium alloy to a melting temperature, driven in rotation about its axis; thus, under the action of centrifugal force, the titanium or the molten titanium alloy is ejected from the end surface of the ingot in the form of liquid droplets which, on cooling, are transformed by solidification into spherical particles having for most with a diameter between 100 and 1000 ⁇ m.
  • a titanium powder is used having particles with a diameter between 100 and 600 ⁇ m.
  • this melting-centrifugation technique when used to prepare the starting powder, it is preferable to subject said powder to a surface treatment before depositing said coating material on the latter.
  • This surface treatment can consist of a degreasing carried out for example by immersing the powder in pure trichlorethylene and then rinsing the latter with methanol.
  • this surface treatment is preferably a treatment to remove the surface layer rich in alphagene element, possibly present on certain particles.
  • the surface layer rich in aluminum powder particles by immersing these particles in sodium carbonate solution maintained at a temperature of about 60-70 ° C, and rinsing. successively the particles with water, acetic acid and water.
  • the coating is deposited on the titanium or titanium alloy powder by conventional techniques.
  • the coating consists of an element such as iron, copper or nickel or of compounds such as nickel-phosphorus or iron-phosphorus
  • chemical deposition techniques are used in particular.
  • the coating material is copper
  • the deposit by electrochemical displacement of copper is advantageously carried out from a solution, for example using a solution consisting of a mixture of a first solution containing copper sulphate, methanol and the aldehyde formic and of a second solution containing soda and double tartrate of potassium and sodium.
  • the coating operation is carried out at room temperature to avoid oxidation of the titanium.
  • the coating has a thickness of a few microns, for example from 1 to 5 ⁇ m.
  • the coated powder is introduced into a mold, then it is subjected to uniaxial compression while maintaining the mold at a temperature between T 1 and T.
  • the pressure exerted on the powder is between 10 and 30 MPa, and the duration of this compression is such that a complete densification of the powder is obtained.
  • a duration greater than 1 hour is requested, a duration of approximately 2 hours is sufficient to achieve this result.
  • This example relates to the preparation of a titanium alloy part from a powder of titanium alloy TA 6 V: alloy which comprises 90% of titanium, 6% of aluminum and 4% of vanadium.
  • Spherical particles having a diameter between 315 and 630 ⁇ m are prepared by the fusion-centrifugation technique from an ingot of this alloy.
  • the spherical particles thus obtained are subjected to a preliminary treatment with a view to removing the aluminum-rich surface layer from the powder particles.
  • the particles are immersed in a solution of 50 g per liter of sodium carbonate, maintained at a temperature of approximately 60-70 ° C, operating in fractions of 150 g of particles for two liters of solution; after immersion, the particles are rinsed with water, then the sodium carbonate is completely eliminated by immersing the particles in 2 liters of 5% acetic acid, and then rinsed twice with water.
  • 150 g of the powder particles are immersed in two liters of solution at room temperature, and the particles are kept in the solution until this solution is completely discolored, that is to say until when the reduction of the copper solution is complete. This operation lasts 3 to 4 days and the particles immersed in the solution are shaken from time to time to obtain a uniform deposit. The particles are then rinsed with water and etanol and dried at 60 ° C.
  • the particles thus coated comprise approximately -1.7% by weight, of copper and the thickness of the coating of each particle is of the order of 1 to 5 ⁇ m.
  • the coated particles are then introduced into an alumina mold obtained by hot spraying or with lost wax.
  • This mold has at its upper part a special cylindrical weight which makes it possible to add to the upper part of the mold an additional quantity of particles.
  • the mold is then placed inside a heating device by interposing between the walls of the mold and the device a refractory metal powder having a low sinterability at the temperature chosen for sintering.
  • the mold containing the powder is then brought to a temperature of approximately 950 ° C. and the mold is then maintained at this temperature under a maximum uniaxial pressure of 30 MPa, for a period of approximately two hours, which ensures complete densification of the powder.
  • the compression of the powder during sintering is carried out by means of a piston of refractory material which takes place at the top of the mold and can slide in the cylindrical counterweight in order to load inside the mold the additional quantity of powder initially placed in this feeder thus helping to eliminate the porosity in the sintered part.
  • the parts obtained After demolding, the parts obtained have a “collar” structure such as that shown in the drawing which corresponds to the presence of large grains (1) having the structure ( ⁇ + ⁇ ) surrounded by a phase (2) of structure exp with fine precipitation a.
  • oligocyclic fatigue resistance tests show that the titanium alloys sintered by uniaxial compression at 950 ° C between 10 and 30 MPa have properties similar to those of forged cast alloys. For example, after repeated stresses at 1Hz between 8 to 80 MPa at 20 ° C, the lifetime at break is 10 5 cycles for a TA e V sintered alloy with addition of copper at 950 ° C / 30 MPa and 10 4 cycles only for the same TA e V without addition, sintered by isostatic compression at 950 ° C / 10 2 MPa.

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  • Powder Metallurgy (AREA)

Description

La présente invention a pour objet un procédé de fabrication de pièces en alliage à base de titane par métallurgie des poudres.The present invention relates to a process for manufacturing titanium-based alloy parts by powder metallurgy.

Jusqu'à présent les procédés utilisés pour réaliser des pièces en titane ou en alliage de titane ont fait appel, soit à des techniques de coulée directe, soit à des techniques de frittage.Up to now, the processes used to produce titanium or titanium alloy parts have used either direct casting techniques or sintering techniques.

Les procédés de réalisation par coulée directe présentent l'inconvénient de nécessiter une étape complémentaire de forgeage à basse température pour obtenir la structure α + β qui permet de conférer aux pièces obtenues une résistance satisfaisante à la fatigue cyclique.The production methods by direct casting have the drawback of requiring an additional low temperature forging step to obtain the structure α + β which makes it possible to give the parts obtained a satisfactory resistance to cyclic fatigue.

En effet, on sait que le titane présente une transformation allotropique à une température de 882 °C ; cette température définit ainsi le domaine de stabilité de deux phases : la phase a de structure hexagonale compacte qui est stable au-dessous de 882 °C et la phase β cubique centrée qui apparaît au-dessus de 882°C.Indeed, it is known that titanium exhibits an allotropic transformation at a temperature of 882 ° C; this temperature thus defines the stability domain of two phases: phase a of compact hexagonal structure which is stable below 882 ° C and the centered cubic β phase which appears above 882 ° C.

Dans le cas d'alliage de titane, la présence de certains éléments d'addition fait apparaître un domaine bi-phasé α + β qui correspond à une structure conférant des propriétés mécaniques améliorées. Cependant, pour conserver cette structure, il est nécessaire de ne pas dépasser lors des opérations de mise en forme la température de transformation allotropique de l'alliage, température qui varie en fonction des éléments présents dans ce dernier. En effet, on sait que la plupart des éléments d'addition utilisés dans les alliages de titane ont tendance a élargir, soit le domaine d'existence de la phase a, soit celui de la phase β. Par ailleurs, certains éléments tels que l'aluminium, sont des éléments alphagènes favorisant la formation de la structure a et d'autres éléments tels que le vanadium, le molybdène, le fer, le chrome, le manganèse, le niobium et le cuivre sont des éléments bétagènes qui favorisent la formation de la structure β.In the case of titanium alloy, the presence of certain addition elements reveals a two-phase domain α + β which corresponds to a structure conferring improved mechanical properties. However, to preserve this structure, it is necessary not to exceed during the forming operations the allotropic transformation temperature of the alloy, a temperature which varies according to the elements present in the latter. Indeed, we know that most of the addition elements used in titanium alloys tend to widen either the domain of existence of the a phase or that of the β phase. In addition, certain elements such as aluminum, are alphagenic elements favoring the formation of the structure a and other elements such as vanadium, molybdenum, iron, chromium, manganese, niobium and copper are betagen elements which promote the formation of the β structure.

Les procédés de fabrication de pièces en titane faisant appel à des techniques de frittage consistent généralement à effectuer un frittage isostatique à chaud sous une pression de 1 à 1,5.102 MPa, pendant 4 h, soit à une température d'environ 950 °C lorsqu'on veut maintenir la phase a dans le cas du titane pur ou lorsqu'on veut obtenir la structure α + β dans le cas d'alliages de titane, soit à une température d'environ 1050 °C lorsqu'on veut se situer dans le domaine de températures qui correspond à la phase β du titane pur ou de ses alliages.The methods for manufacturing titanium parts using sintering techniques generally consist in carrying out isostatic hot sintering under a pressure of 1 to 1.5 × 10 2 MPa, for 4 h, ie at a temperature of approximately 950 ° C. when one wants to maintain phase a in the case of pure titanium or when one wants to obtain the structure α + β in the case of titanium alloys, that is to say at a temperature of approximately 1050 ° C. when one wants to be located in the temperature range which corresponds to the β phase of pure titanium or its alloys.

De tels procédés présentent l'inconvénient de nécessiter des pressions élevées et des durées relativement importantes, ce qui grève le prix de revient des pièces obtenues.Such methods have the drawback of requiring high pressures and relatively long periods of time, which increases the cost price of the parts obtained.

En effet, lorsqu'on utilise des poudres de titane ou d'alliage de titane ayant une granulométrie supérieure à 100 µm, il est impossible d'obtenir une densification satisfaisante de la poudre à des pressions ifnérieures à 1.102 MPa, car la plasticité à chaud du titane est insuffisante pour obtenir une déformation satisfaisante de telles poudres.In fact, when using titanium or titanium alloy powders having a particle size greater than 100 μm, it is impossible to obtain a satisfactory densification of the powder at pressures below 1.10 2 MPa, because the plasticity at hot titanium is insufficient to obtain a satisfactory deformation of such powders.

Cependant, on peut réaliser des pièces en titane ou en alliages de titane par des procédés de frittage classiques, à des pressions inférieures à 50 MPa et à des températures inférieures à 900 °C, en partant de poudres de titane ou d'alliages de titane, corroyées et broyées, mais dans ce cas les pièces obtenues sont fragiles en raison d'un importante contamination intergranulaire en oxygène.However, parts made of titanium or of titanium alloys can be produced by conventional sintering processes, at pressures below 50 MPa and at temperatures below 900 ° C., starting from titanium powders or titanium alloys. , wrought and ground, but in this case the parts obtained are fragile due to significant intergranular oxygen contamination.

On connaît également par le brevet américain n° 3 963 485 un procédé de fabrication de pièces en titane par métallurgie des poudres, selon lequel on utilise un mélange de poudre de titane et de poudre de titane revêtue de fer, que l'on comprime à froid et que l'on fritte ensuite à chaud, ce qui permet d'améliorer la ductilité des pièces obtenues.Also known from US Pat. No. 3,963,485 is a process for manufacturing titanium parts by powder metallurgy, according to which a mixture of titanium powder and titanium powder coated with iron is used, which is compressed to cold and then hot sintered, which improves the ductility of the parts obtained.

Cependant, ce procédé conduit à l'obtention de pièces relativement fragiles.However, this process leads to the production of relatively fragile parts.

Par ailleurs, ces techniques de frittage ne permettent pas d'obtenir directement des pièces de forme complexe telles que des disques de turbine à aubes intégrées, présentant notamment une structure « en collier », c'est-à-dire une structure hétérogène caractérisée par la présence de gros grains entourés et soudés entre eux par des grains finement cristallisés.Furthermore, these sintering techniques do not allow parts of complex shape to be obtained directly, such as turbine blades with integrated blades, in particular having a "collar" structure, that is to say a heterogeneous structure characterized by the presence of large grains surrounded and welded together by finely crystallized grains.

La présente invention a précisément pour objet un procédé de fabrication de pièces en alliage à base de titane par métallurgie des poudres, qui pallie les inconvénients des procédés précités et qui permet d'obtenir de plus des pièces en alliage de titane présentant la structure « en collier ».The present invention specifically relates to a process for manufacturing titanium-based alloy parts by powder metallurgy, which overcomes the drawbacks of the aforementioned processes and which also makes it possible to obtain titanium alloy parts having the structure "in necklace ”.

Le procédé, selon l'invention, de fabrication de pièces en alliage à base de titane par métallurgie des poudres à partir d'une poudre de titane ou d'alliage de titane comprenant un additif, se caractérise en ce qu'il consiste :

  • a) à utiliser une poudre de titane ou d'alliage de titane ayant une granulométrie de 100 à 1 000
    Figure imgb0001
  • à incorporer ledit additif en revêtant la poudre d'un matériau comprenant ledit additif, ledit rr riau étant tel qu'il puisse former au contact du titane ou de l'alliage de titane une phase liquide à une te. pérature T1 inférieure à la température T de transformation allotropique du titane ou de l'alliage de titane constituant ladite poudre,
  • c) à introduire ladite poudre revêtue dans un moule, et
  • d) à comprimer à chaud ladite poudre dans le moule sous une pression de 10 à 30 MPa, à une température comprise entre T1 et T, pendant une durée telle qu'on obtienne une densification complète de la poudre.
The process according to the invention for manufacturing titanium-based alloy parts by powder metallurgy from a titanium or titanium alloy powder comprising an additive, is characterized in that it consists:
  • a) using a titanium or titanium alloy powder having a particle size of 100 to 1000
    Figure imgb0001
  • incorporating said additive by coating the powder with a material comprising said additive, said rr riau being such that it can form in contact with titanium or the titanium alloy a liquid phase at a te. temperature T 1 lower than the temperature T of allotropic transformation of the titanium or of the titanium alloy constituting said powder,
  • c) introducing said coated powder into a mold, and
  • d) hot compressing said powder in the mold under a pressure of 10 to 30 MPa, at a temperature between T 1 and T, for a period such that complete densification of the powder is obtained.

Le procédé tel que caractérisé ci-dessus tire avantageusement profit du fait qu'en modifiant localement par revêtement au moyen d'un matériau approprié tel que le cuivre, la composition superficielle des particules de poudre de titane ou d'alliage de titane, on peut faire apparaître au cours du frittage une phase liquide interstitielle à la surface des grains de poudre et faciliter ainsi les déformations locales, ce qui permet de réaliser le frittage à des températures et des pressions inférieures à celles qui sont habituellement nécessaires pour fritter des poudres ayant une granulométrie de 100 à 1 000 µm.The method as characterized above advantageously takes advantage of the fact that by locally modifying by coating with a suitable material such as copper, the surface composition of the particles of titanium powder or of titanium alloy, it is possible to during the sintering, an interstitial liquid phase appears on the surface of the powder grains and thus facilitate local deformations, which makes it possible to carry out the sintering at temperatures and pressures lower than those usually necessary for sintering powders having a particle size from 100 to 1000 µm.

En effet, compte tenu des dimensions de grains de poudre, le matériau de revêtement qui, dans le cas du cuivre, représente généralement de 1 à 5 % en poids, affecte uniquement la zone corticale des grains sans modifier profondément la composition de l'alliage. Aussi, lors du chauffage, la compression exercée durant la montée en température, c'est-à-dire lorsque le matériau de revêtement est encore présent à la surface des grains, permet d'obtenir une déformation locale de ces derniers et leur densification.Indeed, taking into account the dimensions of powder grains, the coating material which, in the case of copper, generally represents from 1 to 5% by weight, affects only the cortical zone of the grains without profoundly modifying the composition of the alloy . Also, during heating, the compression exerted during the temperature rise, that is to say when the coating material is still present on the surface of the grains, makes it possible to obtain a local deformation of the latter and their densification.

Selon l'invention, le matériau de revêtement peut être constitué par un composé de titane fusible à la température T1, ou de préférence, par un matériau comprenant un élément capable de se combiner avec le titane de la poudre pour former un composé, par exemple un eutectique, fusible à la température T1. Dans ce dernier cas, le revêtement peut être constitué par cet élément ou encore par un composé ou un alliage de cet élément.According to the invention, the coating material can be constituted by a titanium compound fusible at temperature T 1 , or preferably, by a material comprising an element capable of combining with the titanium of the powder to form a compound, by example a eutectic, fuse at temperature T 1 . In the latter case, the coating may consist of this element or also of a compound or an alloy of this element.

De préférence, l'élément utilisé pour former le revêtement est un élément bétagène tel que le fer, le cuivre ou le nickel. De préférence, on utilise le cuivre.Preferably, the element used to form the coating is a betagen element such as iron, copper or nickel. Preferably, copper is used.

Ainsi, on peut améliorer la cinétique de frittage en modifiant localement les phases de l'alliage au cours de la densification.Thus, the sintering kinetics can be improved by locally modifying the phases of the alloy during densification.

En effet, des alliages de titane du type TA6V, c'est-à-dire des alliages comprenant 90 % de titane, 6 % d'aluminium et 4 % de vanadium, sans addition d'élément bétagène tel que le cuivre, présentent une structure biphasée (α + p) dans le domaine de températures 900-980 °C utilisé pour le frittage. Or, cette structure biphasée (α + β présente une résistance à la déformation importante, ce qui ne favorise pas la densification. En revanche, lorsqu'on revêt les grains de poudre au moyen d'un élément bétagène tel que le cuivre, on peut modifier l'équilibre des phases en présence en formant localement une structure monophasée β qui présente au contraire une aptitude à la déformation importante et favorise ainsi le frittage. Cependant, lors de la densification, après.formation de la phase liquide, l'élément bétagène a tendance à diffuser vers le centre des grains. Aussi, pour obtenir localement à la surface des grains cette structure monophasée β qui favorise le frittage, il est avantageux de réaliser le chauffage et l'application de la pression suffisamment rapidement pour éviter une diffusion trop importante de l'élément bétagène et obtenir localement une concentration suffisante de cet élément. De préférence, on réalise le chauffage de la poudre à la température de frittage à une vitesse d'environ 500°C/h à 1 000 °C/h. Enfin, le procédé de l'invention présente l'avantage de conduire à l'obtention de pièces en alliage de titane ayant des propriétés mécaniques améliorées. En effet, le fait de réaliser le frittage dans les. conditions précitées, permet d'obtenir des pièces en alliage de titane présentant une structure dite « en collier », c'est-à-dire une structure hétérogène caractérisée par la présence de gros grains ayant la structure biphasée (a + p) qui sont entourés et soudés entre eux par une phase présentant une structure exp à fine précipitation a du type Windmanstâtten, qui est résistante à la propagation des fissures. On précise que la finesse de la précipitation a dépend en particulier de la vitesse à laquelle on refroidit les pièces obtenues.In fact, titanium alloys of the TA 6 V type, that is to say alloys comprising 90% of titanium, 6% of aluminum and 4% of vanadium, without addition of a betagenic element such as copper, have a two-phase structure (α + p) in the temperature range 900-980 ° C used for sintering. However, this two-phase structure (α + β has a significant resistance to deformation, which does not promote densification. On the other hand, when the powder grains are coated with a betagen element such as copper, it is possible to modify the balance of the phases present by locally forming a single-phase structure β which, on the contrary, has a significant deformation ability and thus promotes sintering. However, during densification, after formation of the liquid phase, the betagen element has a tendency to diffuse towards the center of the grains. Also, to obtain locally on the surface of the grains this single-phase structure β which promotes sintering, it is advantageous to carry out the heating and the application of the pressure quickly enough to avoid excessive diffusion. important of the betagen element and locally obtain a sufficient concentration of this element. Preferably, the powder is heated to the sintering temperature at a vi tesse of about 500 ° C / h to 1000 ° C / h. Finally, the method of the invention has the advantage of leading to the production of titanium alloy parts having improved mechanical properties. Indeed, the fact of carrying out sintering in. aforementioned conditions, makes it possible to obtain titanium alloy parts having a structure known as “in collar”, that is to say a heterogeneous structure characterized by the presence of large grains having the two-phase structure (a + p) which are surrounded and welded together by a phase having an exp structure with fine precipitation a of the Windmanstâtten type, which is resistant to the propagation of cracks. It should be noted that the fineness of the precipitation a depends in particular on the speed at which the parts obtained are cooled.

Selon un mode préférentiel de réalisation du procédé de l'invention, on prépare la poudre de titane ou d'alliage de titane, ayant une granulométrie de 100 à 1 000 µm, par la technique de fusion centrifugation.According to a preferred embodiment of the process of the invention, the powder of titanium or of titanium alloy, having a particle size of 100 to 1000 μm, is prepared by the technique of fusion centrifugation.

On rappelle que cette technique consiste à porter à une température de fusion la surface d'extrémité d'un lingot cylindrique en titane ou en alliage de titane, entraîné en rotation autour de son axe ; ainsi, sous l'action de la force centrifuge, le titane ou l'alliage de titane en fusion est éjecté de la surface d'extrémité du lingot sous la forme de gouttelettes liquides qui en se refroidissant se transforment par solidification en particules sphériques ayant pour la plupart un diamètre compris entre 100 et 1 000 µm.It will be recalled that this technique consists in bringing the end surface of a cylindrical ingot of titanium or titanium alloy to a melting temperature, driven in rotation about its axis; thus, under the action of centrifugal force, the titanium or the molten titanium alloy is ejected from the end surface of the ingot in the form of liquid droplets which, on cooling, are transformed by solidification into spherical particles having for most with a diameter between 100 and 1000 µm.

De préférence, pour la mise en oeuvre du procédé de l'invention, on utilise une poudre de titane ayant des particules de diamètre compris entre 100 et 600 µm.Preferably, for the implementation of the process of the invention, a titanium powder is used having particles with a diameter between 100 and 600 μm.

Par ailleurs, lorsque l'on utilise cette technique de fusion-centrifugation pour préparer la poudre de départ, il est préférable de soumettre ladite poudre à un traitement de surface avant de déposer sur cette dernière ledit matériau de revêtement.Furthermore, when this melting-centrifugation technique is used to prepare the starting powder, it is preferable to subject said powder to a surface treatment before depositing said coating material on the latter.

Ce traitement de surface peut consister en un dégraissage effectué par exemple en immergeant la poudre dans du trichloréthylène pur et en rinçant ensuite cette dernière avec du méthanol.This surface treatment can consist of a degreasing carried out for example by immersing the powder in pure trichlorethylene and then rinsing the latter with methanol.

Lorsque la poudre de départ est obtenue à partir d'un alliage de titane comportant un élément alphagène tel que l'aluminium, ce traitement de surface est de préférence un traitement pour éliminer la couche superficielle riche en élément alphagène, éventuellement présente sur certaines particules.When the starting powder is obtained from a titanium alloy comprising an alphagene element such as aluminum, this surface treatment is preferably a treatment to remove the surface layer rich in alphagene element, possibly present on certain particles.

En effet, lorsque des poudres en alliage de ce type sont préparées par la technique de fusion-centrifugation, il se produit parfois lors du refroidissement des gouttelettes d'alliage liquide un enrichissement superficiel des particules de poudre en élément alphagène, ce qui est indésirable pour l'obtention de bonnes propriétés mécaniques car, après frittage, ces couches riches en élément alphagène risquent de subsister dans la pièce frittée et de favoriser ensuite la propagation des fissures dans une telle pièce.In fact, when alloy powders of this type are prepared by the fusion-centrifugation technique, there is sometimes produced during the cooling of the liquid alloy droplets a surface enrichment of the powder particles with alpha-element, which is undesirable for obtaining good mechanical properties because, after sintering, these layers rich in the alphagene element risk remaining in the sintered part and then promoting the propagation of cracks in such a part.

Dans le cas d'alliage comportant de l'aluminium, on peut éliminer la couche superficielle riche en aluminium des particules de poudre en immergeant ces particules dans solution de carbonate de sodium maintenue à une température d'environ 60-70 °C, et en rinçant . suite successivement les particules avec de l'eau, de l'acide acétique et de l'eau.In the case of an alloy comprising aluminum, the surface layer rich in aluminum powder particles by immersing these particles in sodium carbonate solution maintained at a temperature of about 60-70 ° C, and rinsing. successively the particles with water, acetic acid and water.

Selon l'invention, on dépose le revêtement sur la poudre de titane ou d'alliage de titane par des techniques classiques. Lorsque le revêtement est constitué par un élément tel que le fer, le cuivre ou le nickel ou par des composés tels que le nickel-phosphore ou le fer-phosphore, on utilise en particulier des techniques de dépôt par voie chimique. Lorsque le matériau de revêtement est du cuivre on réalise avantageusement le dépôt par déplacement électrochimique de cuivre à partir d'une solution, en utilisant par exemple une solution constituée par un mélange d'une première solution contenant du sulfate de cuivre, du méthanol et de l'aldéhyde formique et d'une seconde solution contenant de la soude et du tartrate double de potassium et de sodium.According to the invention, the coating is deposited on the titanium or titanium alloy powder by conventional techniques. When the coating consists of an element such as iron, copper or nickel or of compounds such as nickel-phosphorus or iron-phosphorus, chemical deposition techniques are used in particular. When the coating material is copper, the deposit by electrochemical displacement of copper is advantageously carried out from a solution, for example using a solution consisting of a mixture of a first solution containing copper sulphate, methanol and the aldehyde formic and of a second solution containing soda and double tartrate of potassium and sodium.

De préférence, l'opération de revêtement est réalisée à température ambiante pour éviter une oxydation du titane.Preferably, the coating operation is carried out at room temperature to avoid oxidation of the titanium.

Avantageusement, le revêtement a une épaisseur de quelques microns, par exemple de 1 à 5 µm.Advantageously, the coating has a thickness of a few microns, for example from 1 to 5 μm.

Pour l'opération de compression à chaud, on introduit la poudre revêtue dans un moule, puis on la soumet à une compression uniaxiale en maintenant le moule à une température comprise entre T1 et T.For the hot compression operation, the coated powder is introduced into a mold, then it is subjected to uniaxial compression while maintaining the mold at a temperature between T 1 and T.

La pression exercée sur la poudre est comprise entre 10 et 30 MPa, et la durée de cette compression est telle que l'on obtienne une densification complète de la poudre.The pressure exerted on the powder is between 10 and 30 MPa, and the duration of this compression is such that a complete densification of the powder is obtained.

Généralement une durée supérieure à 1 heure est demandée, une durée d'environ 2 heures est suffisante pour atteindre ce résultat.Generally a duration greater than 1 hour is requested, a duration of approximately 2 hours is sufficient to achieve this result.

L'invention sera mieux comprise à la lecture de l'exemple qui suit, donné bien entendu à titre illustratif et non limitatif, et se référant au dessin annexé qui est une micrographie représentant la structure d'une pièce en alliage de titane obtenue par le procédé de l'invention.The invention will be better understood on reading the following example, of course given by way of illustration and not limitation, and referring to the appended drawing which is a micrograph representing the structure of a piece of titanium alloy obtained by method of the invention.

Cet exemple se rapporte à la préparation d'une pièce en alliage de titane à partir d'une poudre d'alliage de titane TA6V : alliage qui comprend 90 % de titane, 6 % d'aluminium et 4 % de vanadium.This example relates to the preparation of a titanium alloy part from a powder of titanium alloy TA 6 V: alloy which comprises 90% of titanium, 6% of aluminum and 4% of vanadium.

On prépare par la technique de fusion-centrifugation à partir d'un lingot de cet alliage, des particules sphériques ayant un diamètre compris entre 315 et 630 µm.Spherical particles having a diameter between 315 and 630 μm are prepared by the fusion-centrifugation technique from an ingot of this alloy.

Ensuite, on soumet les particules sphériques ainsi obtenues à un traitement préliminaire en vue d'éliminer la couche superficielle riche en aluminium des particules de poudre. Dans ce but, on immerge les particules dans une solution à 50 g par litre de carbonate de sodium, maintenue à une température ..d'environ 60-70 °C en opérant par fractions de 150 g de particules pour deux litres de solution ; après immersion, on rince les particules avec de l'eau, puis on élimine complètement le carbonate de sodium en immergeant les particules dans 2 litres d'acide acétique à 5 %, et on rince ensuite deux fois à l'eau.Then, the spherical particles thus obtained are subjected to a preliminary treatment with a view to removing the aluminum-rich surface layer from the powder particles. For this purpose, the particles are immersed in a solution of 50 g per liter of sodium carbonate, maintained at a temperature of approximately 60-70 ° C, operating in fractions of 150 g of particles for two liters of solution; after immersion, the particles are rinsed with water, then the sodium carbonate is completely eliminated by immersing the particles in 2 liters of 5% acetic acid, and then rinsed twice with water.

Après ce traitement préliminaire, on dépose un revêtement de cuivre sur les particules par la technique de déplacement chimique du cuivre en solution. On utilise une solution de cuivrage obtenue en mélangeant un volume d'une solution aqueuse comprenant :

  • - 10 g/I de CuS04, 5H20, 300 ml/1 de méthanol et 60 ml/l d'aldéhyde formique,
  • - avec un volume d'une solution comportant 40 g par litre de NaOH et 28 g par litre de sel_ de Rochelle (tartrate double de potassium et de sodium).
After this preliminary treatment, a coating of copper is deposited on the particles by the technique of chemical displacement of copper in solution. A copper-plating solution obtained by mixing a volume of an aqueous solution comprising:
  • - 10 g / I of CuS0 4 , 5H 2 0, 300 ml / 1 of methanol and 60 ml / l of formaldehyde,
  • - with a volume of a solution comprising 40 g per liter of NaOH and 28 g per liter of Rochelle salt (double potassium and sodium tartrate).

Pour réaliser le revêtement, on immerge 150 g des particules de poudre dans deux litres de solution à température ambiante, et on maintient les particules dans la solution jusqu'à ce que cette solution soit complètement décolorée, c'est-à-dire jusqu'au moment où la réduction de la solution de cuivrage est complète. Cette opération dure 3 à 4 jours et on secoue de temps en temps les particules immergées dans la solution pour obtenir un dépôt homogène. On rince ensuite les particules à l'eau et à l'étanol et on les sèche à 60 °C..To make the coating, 150 g of the powder particles are immersed in two liters of solution at room temperature, and the particles are kept in the solution until this solution is completely discolored, that is to say until when the reduction of the copper solution is complete. This operation lasts 3 to 4 days and the particles immersed in the solution are shaken from time to time to obtain a uniform deposit. The particles are then rinsed with water and etanol and dried at 60 ° C.

Les particules ainsi revêtues comprennent environ -1,7 % en poids, de cuivre et l'épaisseur du revêtement de chaque particule est de l'ordre de 1 à 5 µm.The particles thus coated comprise approximately -1.7% by weight, of copper and the thickness of the coating of each particle is of the order of 1 to 5 μm.

On introduit ensuite les particules revêtues dans un moule en alumine obtenu par la projection à chaud ou à la cire perdue. Ce moule comporte à sa partie supérieure une masselotte cylindrique particulière qui permet d'ajouter à la partie supérieure du moule une quantité supplémentaire de particules.The coated particles are then introduced into an alumina mold obtained by hot spraying or with lost wax. This mold has at its upper part a special cylindrical weight which makes it possible to add to the upper part of the mold an additional quantity of particles.

On dispose ensuite le moule à l'intérieur d'un dispositif chauffant en intercalant entre les parois du moule et le dispositif une poudre métallique réfractaire présentant une faible aptitude au frittage à la température choisie pour le frittage.The mold is then placed inside a heating device by interposing between the walls of the mold and the device a refractory metal powder having a low sinterability at the temperature chosen for sintering.

On porte ensuite le moule contenant la poudre à une température d'environ 950 °C et on maintient ensuite le moule à cette température sous une pression uniaxiale maximale de 30 MPa, pendant une durée d'environ deux heures, ce qui permet d'assurer une densification complète de la poudre.The mold containing the powder is then brought to a temperature of approximately 950 ° C. and the mold is then maintained at this temperature under a maximum uniaxial pressure of 30 MPa, for a period of approximately two hours, which ensures complete densification of the powder.

La mise en compression de la poudre pendant le frittage est réalisée au moyen d'un piston en matériau réfractaire qui prend place à la partie supérieure du moule et peut coulisser dans la masselotte cylindrique afin de charger à l'intérieur du moule la quantité supplémentaire de poudre placée initialement dans cette masselotte en contribuant ainsi à éliminer la porosité dans la pièce frittée.The compression of the powder during sintering is carried out by means of a piston of refractory material which takes place at the top of the mold and can slide in the cylindrical counterweight in order to load inside the mold the additional quantity of powder initially placed in this feeder thus helping to eliminate the porosity in the sintered part.

Après démoulage, les pièces obtenues présentent une structure « en collier » telle que celle représentée sur le dessin qui correspond à la présence de gros grains (1) ayant la structure (α + β) entourés par une phase (2) de structure exp avec une fine précipitation a.After demolding, the parts obtained have a “collar” structure such as that shown in the drawing which corresponds to the presence of large grains (1) having the structure (α + β) surrounded by a phase (2) of structure exp with fine precipitation a.

Par ailleurs, on note que les variations de microdureté sont insignifiantes.Furthermore, it should be noted that the variations in microhardness are insignificant.

Les propriétés mécaniques de résistance à la rupture R, de limite élastique 0,2 %, d'allongement A (en %) et de striction de la pièce ainsi obtenue sont données dans le tableau 1 ci-joint.The mechanical properties of breaking strength R, 0.2% elastic limit, elongation A (in%) and necking of the part thus obtained are given in table 1 attached.

Dans ce tableau, on a donné à titre comparatif les propriétés mécaniques de pièces obtenues selon les techniques de l'art antérieur, c'est-à-dire par frittage isostatique à 960 °C, sous 102 MPa, pendant quatre heures, d'une poudre non revêtue de cuivre ayant la même granulométrie, ou par frittage uniaxial à 950 °C, sous 30 MPa, pendant deux heures d'une poudre broyée et corroyée du même alliage. Par ailleurs, dans ce tableau, on a également donné les caractéristiques correspondant à la norme Air P 63.In this table, the mechanical properties of parts obtained according to the techniques of the prior art have been given for comparison, that is to say by isostatic sintering at 960 ° C., under 10 2 MPa, for four hours, d 'a powder not coated with copper having the same particle size, or by uniaxial sintering at 950 ° C, under 30 MPa, for two hours of a ground and wrought powder of the same alloy. In addition, in this table, we have also given the characteristics corresponding to the Air P 63 standard.

Au vu de ce tableau, on remarque que le procédé de l'invention permet également d'améliorer les propriétés mécaniques des pièces obtenues.In view of this table, it can be seen that the process of the invention also makes it possible to improve the mechanical properties of the parts obtained.

D'autre part, les essais de résistance à la fatigue oligocyclique montrent que les alliages de titane frittés par compression uniaxiale à 950 °C entre 10 et 30 MPa présentent des propriétés analogues à celles des alliages coulés forgés. Par exemple après sollicitations répétées à lHz entre 8 à 80 MPa à 20 °C, les durées de vie à rupture sont de 105 cycles pour un alliage TAeV fritté avec addition de cuivre à 950°C/30 MPa et 104 cycles seulement pour le même TAeV sans addition, fritté par compression isostatique à 950 °C/102 MPa.On the other hand, oligocyclic fatigue resistance tests show that the titanium alloys sintered by uniaxial compression at 950 ° C between 10 and 30 MPa have properties similar to those of forged cast alloys. For example, after repeated stresses at 1Hz between 8 to 80 MPa at 20 ° C, the lifetime at break is 10 5 cycles for a TA e V sintered alloy with addition of copper at 950 ° C / 30 MPa and 10 4 cycles only for the same TA e V without addition, sintered by isostatic compression at 950 ° C / 10 2 MPa.

Par ailleurs, il convient de noter que lorsqu'on soumet les pièces obtenues selon l'exemple ci-dessus, à un traitement thermique de recuit à 700°C pendant deux heures, on ne modifie pas leurs caractéristiques de traction. Ainsi, on constate que les propriétés optimales sont obtenues immédiatement.Furthermore, it should be noted that when the parts obtained according to the above example are subjected to an annealing heat treatment at 700 ° C. for two hours, their tensile characteristics are not modified. Thus, it can be seen that the optimal properties are obtained immediately.

Enfin, les pièces obtenues selon le procédé de l'invention se comportent bien à la soudure, ce qui n'est pas le cas des pièces obtenues par les procédés de l'art antérieur.

Figure imgb0002
Finally, the parts obtained according to the method of the invention behave well in welding, which is not the case of the parts obtained by the methods of the prior art.
Figure imgb0002

Claims (14)

1. Process for the production of titanium alloy bodies by powder metallurgy from a powder of titanium or a titanium alloy containing an additive, characterized in that it comprises :
a) employing a powder of titanium or a titanium alloy having a particle size from 100 to 1 000 microns,
b) incorporating said additive by coating the powder with a material comprising said additive, said material being such that, when in contact with titanium or titanium alloy, it is able to form a phase that is liquid at a temperature Ti, below the allotropic transformation temperature T of the titanium or titanium alloy constituting said powder,
c) introducing said coated powder into a mould, and
d) heating and compressing said powder in the mould at a pressure of 10 to 30 Mpa, and at a temperature between T1 and T, for a period such that the powder is çompletely densified.
2. Process according to claim 1, characterized in that the coating material is a titanium compound that is molten at the temperature T1.
3. Process according to claim 1, characterized in that the coating material comprises an element that is capable of combining with the titanium in said powder to form a compound that is molten at the temperature T1.
4. Process according to claim 3, characterized in that the said element is a betagenic element.
5. Process according to claim 4, characterized in that said element is selected from the group comprising nickel, iron and copper.
6. Process according to any one of claims 1 to 5, characterized in that the said powder of titanium or titanium alloy is prepared by cooling the liquid drops of titanium or titanium alloy obtained by melting the end surface of a cylindrical ingot of titanium or titanium alloy, while it is rotated around its axis.
7. Process according to claim 6, characterized in that the powder is subjected to a surface treatment before deposition of the coating.
8. Process according to claim 7, characterized in that the surface treatment comprises degreasing.
9. Process according to claim 7, characterized in that said powder is a powder of a titanium- aluminium alloy, and the surface treatment is a treatment adapted to remove the external aluminium-rich layer from the surface of the grains.
10. Process according to any one of claims 1 to 9, characterized in that said particles have a diameter between 100 and 600 µm.
11: Process according to any one of claims 3 to 10, characterized in that the coating material is copper.
12. Process according to claim 11, characterized in that the copper is deposited on said powder by chemical displacement from a solution.
13. Process according to claim 12, characterized in that said solution is obtained by mixing a first solution, comprising copper sulphate, methanol and formaldehyde, and a second solution comprising sodium hydroxide and sodium potassium tartrate.
14. Process according to any one of claims 1 to 13, characterized in that said coating has a thickness from 1 to 5 wm.
EP80401206A 1979-08-27 1980-08-22 Process of making titanium alloy articles by powder metallurgy Expired EP0024984B1 (en)

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US4714587A (en) * 1987-02-11 1987-12-22 The United States Of America As Represented By The Secretary Of The Air Force Method for producing very fine microstructures in titanium alloy powder compacts
US4851055A (en) * 1988-05-06 1989-07-25 The United States Of America As Represented By The Secretary Of The Air Force Method of making titanium alloy articles having distinct microstructural regions corresponding to high creep and fatigue resistance
US4808249A (en) * 1988-05-06 1989-02-28 The United States Of America As Represented By The Secretary Of The Air Force Method for making an integral titanium alloy article having at least two distinct microstructural regions
US5234487A (en) * 1991-04-15 1993-08-10 Tosoh Smd, Inc. Method of producing tungsten-titanium sputter targets and targets produced thereby
JP2849710B2 (en) * 1996-08-27 1999-01-27 工業技術院長 Powder forming method of titanium alloy
US6589310B1 (en) * 2000-05-16 2003-07-08 Brush Wellman Inc. High conductivity copper/refractory metal composites and method for making same
US6599466B1 (en) 2002-01-16 2003-07-29 Adma Products, Inc. Manufacture of lightweight metal matrix composites with controlled structure
JP2008502808A (en) * 2004-06-10 2008-01-31 ホーメット コーポレーション Near β-type titanium alloy castings after heat treatment
GB0413135D0 (en) * 2004-06-12 2004-07-14 Rolls Royce Plc A method of manufacturing a component by consolidating a metal powder
US7833472B2 (en) * 2005-06-01 2010-11-16 General Electric Company Article prepared by depositing an alloying element on powder particles, and making the article from the particles
US8028812B2 (en) * 2007-07-23 2011-10-04 Gerald Martino Brake rotors for vehicles
RU2572928C2 (en) * 2010-05-31 2016-01-20 Тохо Титаниум Ко., Лтд. Powder mix for production of titanium alloy, titanium alloy made thereof and methods of their fabrication
CN103418785B (en) * 2012-05-23 2016-05-25 北京航空航天大学 A kind of preparation method of corrosion-resistant titanium/ruthenium-oxide composite granule
CN110937884A (en) * 2019-12-05 2020-03-31 中国航发北京航空材料研究院 Preparation method of titanium-based alloy powder hot isostatic pressing sheath inner cavity isolation layer

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3379522A (en) * 1966-06-20 1968-04-23 Titanium Metals Corp Dispersoid titanium and titaniumbase alloys
US3341325A (en) * 1966-12-09 1967-09-12 Crucible Steel Co America Method for producing alloy-steel articles
CA989649A (en) * 1972-05-01 1976-05-25 Edward L. Thellmann Method of producing sintered titanium base articles
US3963485A (en) * 1972-05-01 1976-06-15 Gould Inc. Method of producing sintered titanium base articles
US3953205A (en) * 1973-06-06 1976-04-27 United Technologies Corporation Production of homogeneous alloy articles from superplastic alloy particles
CA1042735A (en) * 1974-07-12 1978-11-21 Sherritt Gordon Mines Limited Copper coated composite powders and method of production thereof
DE2448738C3 (en) * 1974-10-12 1978-08-03 W.C. Heraeus Gmbh, 6450 Hanau Metallic thin-film composite
GB1444530A (en) * 1975-06-11 1976-08-04 Council Scient Ind Res Production of composite powders

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