EP0005668B1 - Process for producing alloy articles by powder metallurgy - Google Patents

Process for producing alloy articles by powder metallurgy Download PDF

Info

Publication number
EP0005668B1
EP0005668B1 EP79400302A EP79400302A EP0005668B1 EP 0005668 B1 EP0005668 B1 EP 0005668B1 EP 79400302 A EP79400302 A EP 79400302A EP 79400302 A EP79400302 A EP 79400302A EP 0005668 B1 EP0005668 B1 EP 0005668B1
Authority
EP
European Patent Office
Prior art keywords
alloy
powder
temperature
process according
nickel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP79400302A
Other languages
German (de)
French (fr)
Other versions
EP0005668A1 (en
Inventor
Jacques Devillard
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
Publication of EP0005668A1 publication Critical patent/EP0005668A1/en
Application granted granted Critical
Publication of EP0005668B1 publication Critical patent/EP0005668B1/en
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/0433—Nickel- or cobalt-based alloys
    • 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
    • B22F1/09—Mixtures of metallic powders

Definitions

  • the subject of the present invention is a method for manufacturing alloy parts by powder metallurgy, and more particularly a method for manufacturing superalloy parts based on nickel or on iron, having the form of discs or blades of turbines for rotating machines.
  • the powder metallurgy manufacturing methods make it possible to avoid the aforementioned drawback because by dividing the alloy into microlingots which are then combined by sintering, it is possible to produce highly alloyed preforms having a minimum of segregation.
  • the present invention specifically relates to a method of manufacturing parts in alloys by powder metallurgy which overcomes the aforementioned drawbacks because it allows sintering in the liquid phase without requiring the addition of a foreign element and without implementing high pressures.
  • the method according to the invention is characterized in that it consists in preparing from the constituents of said alloy a homogeneous mixture of a powder of an alloy A 1 and a powder of an alloy A 2 , said alloys A 1 and A 2 comprising all the constituents of said alloy but having a different content of at least one addition element so that the alloy A 1 has a liquid phase at a temperature T 1 lower than the temperature T 2 at which the alloy A 2 forms a liquid phase, and sintering under load the mixture of said powders at a temperature between T 1 and T 2 while maintaining the mixture at said temperature for at most one hour.
  • the fillers are formed by a mixture of two powders having the same basic constituents and the composition of one of the powders differs from the other by the presence of an element lowering the melting point, so that this powder forms a liquid phase at a temperature below the melting temperature of the metal parts to be repaired.
  • the metal charge is compacted, then heated, possibly subjected to an external pressure, until one of the phases melts, so that the alloy is isothermally resolidified at this temperature.
  • the large diffusion of the element lowering the melting point of one of the powders is used to isothermally solidify the load and weld it to the part to be repaired.
  • said alloy is preferably chosen from the group comprising nickel-based alloys and iron-based alloys.
  • the method as characterized above advantageously takes advantage of the fact that, starting from a mixture of two powders forming liquid phases at different temperatures, it is possible to carry out sintering in the liquid phase at a lower temperature by avoiding that the all of the powder forms a liquid phase.
  • At least one of said powders is prepared by rapidly cooling liquid droplets which have been formed from a cylindrical ingot of said alloy by bringing the surface d to a melting temperature. end of said ingot rotated about its axis so that the molten alloy is ejected from the end surface of the ingot, under the action of centrifugal force, which leads, by solidification of the ejected droplets, to obtaining powder particles comprising a solid phase whose composition does not correspond to equilibrium, said solid phase being fusible at a temperature below the theoretical burning temperature of the alloy.
  • the liquid present at the solidification interface rapidly reaches the eutectic composition while the solidified part of the alloy does not have the composition corresponding to the solubility limit.
  • the concentration of the main pale constituents of the alloys A 1 and A 2 is identical and only the contents of certain additives present at minor concentrations vary, in particular, the contents of additives such as carbon, boron and zirconium .
  • the process of the invention proves to be particularly advantageous since the use of two types of powder makes it possible to form a liquid phase only in a single type of powder without requiring the addition of a foreign element and by modifying only very little the content of one of the powders in one of the constituents of the alloy.
  • the mixture of powders is, for example, constituted by equal volumes of powder of alloy A 1 and of powder of alloy A 2 whose particle sizes are substantially identical, for example on the order of 50 to 300 ⁇ .
  • variable volumes of powder of alloy A 1 and of powder of alloy A 2 provided, however, that in the homogeneous mixture of powders, each less fusible particle of alloy A 2 is in contact with a particle plus alloy fuse A 1 .
  • variable particle sizes can be used for each of the powders of alloy A 1 and of alloy A 2 , for example in order to obtain a more compact stacking of powder particles.
  • the duration and pressure of sintering are chosen according to the nature of the alloy.
  • the sintering pressure is advantageously of the order of 100 bars and the duration of sixty minutes.
  • the powder mixture For the sintering operation of the powder mixture, it is preferable to bring the powder mixture to the sintering temperature as quickly as possible, for example by heating in such a way that the temperature of the powder mixture increases. 1000 to 10000 ° C per hour. By operating in this way, large diffusion and homogenization during heating of the powder are avoided, which would be detrimental to obtaining good sintering kinetics.
  • the powder mixture when the powder mixture is at the sintering temperature, it is important to keep the powder mixture at this sintering temperature only for a relatively short period of at most one hour to avoid diffusion and magnification. grains and thus obtain a dense structure well sintered and homogeneous overall.
  • the first powder of alloy A 1 contains 12% chromium, 18% cobalt, 3% molybdenum, 4% titanium, 5 % aluminum, 0.011% boron, 0.05% zirconium and 0.2 % carbon, the rest being nickel, and the second A 2 alloy powder contains 12% chromium. 18% cobalt, 3% molybdenum, 4% titanium, 5% aluminum, 0.011% boron, 0.05% zirconium and 0.003% carbon, the rest being nickel.
  • the powders of alloy A 1 and of alloy A 2 each have a particle size between 50 and 300 w.
  • the mold is then placed inside a heating device, by inserting between the walls of the mold and the device a refractory metal powder having a low sinterability, at the temperature chosen for sintering the powder mixture.
  • the mold containing the powder mixture is then brought to a temperature of approximately 1290 ° C., by heating the mold filled with powders very quickly, for example by increasing its temperature by 1000 ° C. per hour.
  • the mold is then kept at the chosen temperature of 1290 ° C., under a uniaxial pressure of 50 to 100-bars, for a period of approximately sixty minutes to ensure the sintering of the powder mixture.
  • 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 weight, thus helping to eliminate the porosity in the sintered part.
  • the parts After demolding, the parts have a perfect surface condition with grains with an average size of 50 ⁇ .

Description

La présente invention a pour objet un procédé de fabrication de pièces en alliage par métallurgie des poudres, et plus particulièrement un procédé de fabrication de pièces en superalliage à base de nickel ou à base de fer, présentant la forme de disques ou d'aubes de turbines de machines tournantes.The subject of the present invention is a method for manufacturing alloy parts by powder metallurgy, and more particularly a method for manufacturing superalloy parts based on nickel or on iron, having the form of discs or blades of turbines for rotating machines.

Jusqu'à présent, on a réalisé de telles pièces soit par des techniques de coulée et de forgeage, soit par métallurgie des poudres.So far, such parts have been produced either by casting and forging techniques, or by powder metallurgy.

Les procédés de fabrication par coulée et par forgeage présentent certains inconvénients, notamment pour la réalisation de pièces en alliage très chargé en éléments d'addition car les opérations de coulée et de transformation par forgeage deviennent de plus en plus complexes en raison des difficultés dues principalement à l'apparition de ségrégations qui augmentent la fragilité des alliages et qui peuvent donner lieu à l'apparition de fissures.The manufacturing methods by casting and by forging have certain drawbacks, in particular for the production of alloy parts very loaded with addition elements because the casting and transformation operations by forging become more and more complex due to the difficulties due mainly the appearance of segregations which increase the brittleness of the alloys and which can give rise to the appearance of cracks.

Les procédés de fabrication par métallurgie des poudres permettent d'éviter l'inconvénient précité car en divisant l'alliage en microlingots que l'on associe ensuite par frittage, il est possible de réaliser des préformes très alliées présentant un minimum de ségrégations.The powder metallurgy manufacturing methods make it possible to avoid the aforementioned drawback because by dividing the alloy into microlingots which are then combined by sintering, it is possible to produce highly alloyed preforms having a minimum of segregation.

Cependant, ces procédés présentent d'autres inconvénients liés principalement au mode de frittage des poudres, qui est généralement réalisé par compression hydrostatique ou par frittage en phase liquide.However, these methods have other drawbacks mainly related to the sintering mode for powders, which is generally carried out by hydrostatic compression or by sintering in the liquid phase.

En effet, les procédés faisant appel à un frittage par compression hydrostatique sont très onéreux car ils exigent l'emploi de dispositifs très complexes pour obtenir les pressions aux températures très élevées nécessaires pour le frittage. Par ailleurs, ils sont peu adaptés à la réalisation de disques à aubes intégrées.Indeed, the processes using hydrostatic compression sintering are very expensive because they require the use of very complex devices to obtain the pressures at very high temperatures necessary for sintering. In addition, they are not very suitable for making discs with integrated blades.

Les procédés faisant appel à un frittage en phase liquide nécessitent l'emploi d'un adjuvant de frittage tel que le nickel phosphoreux pour abaisser la température et la pression de mise en forme de la poudre, et l'adjonction d'un élément étranger, même à des teneurs très faibles, risque d'altérer profondément les propriétés mécaniques de l'alliage.The processes using liquid phase sintering require the use of a sintering aid such as phosphorous nickel to lower the temperature and the pressure for shaping the powder, and the addition of a foreign element, even at very low contents, risk of profoundly altering the mechanical properties of the alloy.

La présente invention a précisément pour objet un procédé de fabrication de pièces en alliages par métallurgie des poudres qui pallie les inconvénients précités car il permet de réaliser un frittage en phase liquide sans nécessiter l'adjonction d'un élément étranger et sans mettre en oeuvre des pressions élevées.The present invention specifically relates to a method of manufacturing parts in alloys by powder metallurgy which overcomes the aforementioned drawbacks because it allows sintering in the liquid phase without requiring the addition of a foreign element and without implementing high pressures.

Le procédé selon l'invention se caractérise en ce qu'il consiste à préparer à partir des constituants dudit alliage un mélange homogène d'une poudre d'un alliage A1 et d'une poudre d'un alliage A2, lesdits alliages A1 et A2 comportant tous les constituants dudit alliage mais ayant une teneur différente en au moins un élément d'addition de façon que l'alliage A1 ait une phase liquide à une température T1 inférieure à la température T2 à laquelle l'alliage A2 forme une phase liquide, et à fritter sous charge le mélange desdites poudres à une température comprise entre T1 et T2 en maintenant le mélange à ladite température pendant au plus une heure.The method according to the invention is characterized in that it consists in preparing from the constituents of said alloy a homogeneous mixture of a powder of an alloy A 1 and a powder of an alloy A 2 , said alloys A 1 and A 2 comprising all the constituents of said alloy but having a different content of at least one addition element so that the alloy A 1 has a liquid phase at a temperature T 1 lower than the temperature T 2 at which the alloy A 2 forms a liquid phase, and sintering under load the mixture of said powders at a temperature between T 1 and T 2 while maintaining the mixture at said temperature for at most one hour.

Dans l'art antérieur, on a déjà envisagé l'emploi de charges métalliques composées de deux poudres différentes pour obturer des fissures dans des pièces métalliques, comme cela est décrit dans le brevet FR-A-2 296 491.In the prior art, consideration has already been given to the use of metallic fillers composed of two different powders for sealing cracks in metallic parts, as described in patent FR-A-2 296 491.

Selon ce brevet, les charges sont formées par un mélange de deux poudres ayant les mêmes constituants de base et la composition de l'une des poudres diffère de l'autre par la présence d'un élément abaissant le point de fusion, de manière que cette poudre forme une phase liquide à une température inférieure à la température de fusion des pièces métalliques à réparer. La charge métallique est tassée, puis chauffée, éventuellement soumise à une pression extérieure, jusqu'à fusion de l'une des phases, afin que l'alliage se resolidifie isothermiquement à cette température.According to this patent, the fillers are formed by a mixture of two powders having the same basic constituents and the composition of one of the powders differs from the other by the presence of an element lowering the melting point, so that this powder forms a liquid phase at a temperature below the melting temperature of the metal parts to be repaired. The metal charge is compacted, then heated, possibly subjected to an external pressure, until one of the phases melts, so that the alloy is isothermally resolidified at this temperature.

Ainsi, on utilise la diffusion importante de l'élément abaissant le point de fusion de l'une des poudres pour resolidifier isothermiquement la charge et la souder à la pièce à réparer.Thus, the large diffusion of the element lowering the melting point of one of the powders is used to isothermally solidify the load and weld it to the part to be repaired.

Selon l'invention, ledit alliage est de préférence choisi dans le groupe comprenant les alliages à base de nickel et les alliages à base de fer.According to the invention, said alloy is preferably chosen from the group comprising nickel-based alloys and iron-based alloys.

Le procédé tel que caractérisé ci-dessus tire avantageusement profit du fait que, en partant d'un mélange de deux poudres formant des phases liquides à des températures différentes, on peut réaliser le frittage en phase liquide à une température plus basse en évitant que la totalité de la poudre ne forme une phase liquide.The method as characterized above advantageously takes advantage of the fact that, starting from a mixture of two powders forming liquid phases at different temperatures, it is possible to carry out sintering in the liquid phase at a lower temperature by avoiding that the all of the powder forms a liquid phase.

Selon un mode de réalisation du procédé de l'invention, on prépare au moins l'une desdites poudres en refroidissant rapidement des gouttelettes liquides qui ont été formées à partir d'un lingot cylindrique dudit alliage en portant à une température de fusion la surface d'extrémité dudit lingot entraîné en rotation autour de son axe de sorte que l'alliage en fusion est éjecté de la surface d'extrémité du lingot, sous l'action de la force centrifuge, ce qui conduit, par solidification des gouttelettes éjectées, à l'obtention de particules de poudre comportant une phase solide dont la composition ne correspond pas à l'équilibre, ladite phase solide étant fusible à une température inférieure à la température théorique de brûlure de l'alliage.According to one embodiment of the process of the invention, at least one of said powders is prepared by rapidly cooling liquid droplets which have been formed from a cylindrical ingot of said alloy by bringing the surface d to a melting temperature. end of said ingot rotated about its axis so that the molten alloy is ejected from the end surface of the ingot, under the action of centrifugal force, which leads, by solidification of the ejected droplets, to obtaining powder particles comprising a solid phase whose composition does not correspond to equilibrium, said solid phase being fusible at a temperature below the theoretical burning temperature of the alloy.

En refroidissant rapidement ces gouttelettes liquides on ne suit pas les lois normales d'équilibre et l'apparition des différentes phases de solidification se produit hors équilibre.By rapidly cooling these liquid droplets, the normal laws of equilibrium are not followed and the appearance of the various solidification phases occurs out of equilibrium.

Dans le cas d'un alliage à base de nickel, le liquide présent à l'interface de solidification atteint rapidement la composition eutectique alors que la partie solidifiée de l'alliage ne présente pas la composition correspondant à la limite de solubilité.In the case of a nickel-based alloy, the liquid present at the solidification interface rapidly reaches the eutectic composition while the solidified part of the alloy does not have the composition corresponding to the solubility limit.

Selon l'invention la concentration des principaux constituants des alliages A1 et A2 est identique et seules varient les teneurs en certains éléments d'addition présents à des concentrations peu importantes, en particulier, les teneurs d'éléments d'addition tels que le carbone, le bore et le zirconium.According to the invention the concentration of the main pale constituents of the alloys A 1 and A 2 is identical and only the contents of certain additives present at minor concentrations vary, in particular, the contents of additives such as carbon, boron and zirconium .

En effet, en abaissant la concentration en carbone, en bore, ou en zirconium d'un alliage à base de nickel, on parvient à élever la température de brûlure de cet alliage. Ainsi, la diminution de la teneur en carbone d'un alliage de nickel contenant 12 % de chrome, 18 % de cobalt, 3 % de molybdène, 4% de titane, 5% d'aiuminium, 0,011 % de bore, 0,05 % de zirconium, permet d'augmenter sa température de brûlure de plus de 60°C lorsqu'on passe d'une teneur en carbone de 0,2 % à une teneur de 0,003 %.In fact, by lowering the carbon, boron or zirconium concentration of a nickel-based alloy, it is possible to raise the burn temperature of this alloy. Thus, the decrease in the carbon content of a nickel alloy containing 12% chromium, 18% cobalt, 3% molybdenum, 4% titanium, 5% aluminum, 0.011% boron, 0.05 % zirconium, increases its burn temperature by more than 60 ° C when going from a carbon content of 0.2% to a content of 0.003%.

Le procédé de l'invention se révèle particulièrement avantageux car l'emploi de deux types de poudre permet de ne former une phase liquide que dans un seul type de poudre sans nécessiter l'adjonction d'un élément étranger et en ne modifiant que très peu la teneur de l'une des poudres en l'un des constituants de l'alliage.The process of the invention proves to be particularly advantageous since the use of two types of powder makes it possible to form a liquid phase only in a single type of powder without requiring the addition of a foreign element and by modifying only very little the content of one of the powders in one of the constituents of the alloy.

Pour la mise en oeuvre du procédé de l'invention, le mélange de poudres est, par exemple, constitué par des volumes égaux de poudre d'alliage A1 et de poudre d'alliage A2 dont les granulométries sont sensiblement identiques, par exemple de l'ordre de 50 à 300 µ. Cependant, on peut aussi utiliser des volumes variables de poudre d'alliage A1 et de poudre d'alliage A2 à condition toutefois que dans le mélange homogène de poudres, chaque particule moins fusible d'alliage A2 soit en contact avec une particule plus fusible d'alliage A1. Par ailleurs, on peut utiliser des granulométries variables pour chacune des poudres d'alliage A1 et d'alliage A2, par exemple dans le but d'obtenir un empilage de particules de poudres plus compact.For the implementation of the process of the invention, the mixture of powders is, for example, constituted by equal volumes of powder of alloy A 1 and of powder of alloy A 2 whose particle sizes are substantially identical, for example on the order of 50 to 300 µ. However, it is also possible to use variable volumes of powder of alloy A 1 and of powder of alloy A 2 provided, however, that in the homogeneous mixture of powders, each less fusible particle of alloy A 2 is in contact with a particle plus alloy fuse A 1 . Furthermore, variable particle sizes can be used for each of the powders of alloy A 1 and of alloy A 2 , for example in order to obtain a more compact stacking of powder particles.

Pour le frittage, la durée et la pression du frittage sont choisies en fonction de la nature de l'alliage. Ainsi, dans le cas de pièces en alliage à base de nickel, la pression de frittage est avantageusement de l'ordre de 100 bars et la durée de soixante minutes.For sintering, the duration and pressure of sintering are chosen according to the nature of the alloy. Thus, in the case of nickel-based alloy parts, the sintering pressure is advantageously of the order of 100 bars and the duration of sixty minutes.

Pour l'opération de frittage du mélange de poudres, il est préférable de porter le plus rapidement possible le mélange de poudres à la température de frittage, par exemple en réalisant le chauffage de façon telle qu'on augmente la température du mélange de poudres de 1000 à 10000°C par heure. En opérant ainsi, on évite une diffusion importante et une homogénéisation au cours du chauffage de la poudre, ce qui serait néfaste à l'obtention d'une bonne cinétique de frittage.For the sintering operation of the powder mixture, it is preferable to bring the powder mixture to the sintering temperature as quickly as possible, for example by heating in such a way that the temperature of the powder mixture increases. 1000 to 10000 ° C per hour. By operating in this way, large diffusion and homogenization during heating of the powder are avoided, which would be detrimental to obtaining good sintering kinetics.

Par ailleurs, lorsque le mélange de poudres se trouve à la température de frittage, il est important de ne maintenir le mélange de poudres à cette température de frittage que pendant une durée relativement courte d'au plus une heure pour éviter la diffusion et le grossissement des grains et obtenir ainsi une structure dense bien frittée et homogène globalement.Furthermore, when the powder mixture is at the sintering temperature, it is important to keep the powder mixture at this sintering temperature only for a relatively short period of at most one hour to avoid diffusion and magnification. grains and thus obtain a dense structure well sintered and homogeneous overall.

L'invention sera mieux comprise à la lecture de l'exemple qui suit donné bien entendu à titre illustratif et non limitatif, se rapportant à la fabrication d'une pièce en alliage de nickel.The invention will be better understood on reading the example which follows, of course given by way of illustration and not limitation, relating to the manufacture of a part made of nickel alloy.

ExempleExample

En premier lieu, on prépare à partir des constituants de l'alliage de nickel deux poudres d'alliages A1 et A2 qui se différencient par leur teneur en carbone et en nickel. La première poudre d'alliage A1 contient 12 % de chrome, 18 % de cobalt, 3 % de molybdène, 4 % de titane, 5 % d'aluminium, 0,011 % de bore, 0,05 % de zirconium et 0,2 % de carbone, le reste étant constitué par du nickel, et la seconde poudre d'alliage A2 contient 12 % de chrome. 18 % de cobalt, 3 %de molybdène, 4 % de titane, 5 % d'aluminium, 0,011 % de bore, 0,05 % de zirconium et 0,003 % de carbone, le reste étant constitué par du nickel.First, two powders of alloys A 1 and A 2 are prepared from the constituents of the nickel alloy, which differ in their carbon and nickel content. The first powder of alloy A 1 contains 12% chromium, 18% cobalt, 3% molybdenum, 4% titanium, 5 % aluminum, 0.011% boron, 0.05% zirconium and 0.2 % carbon, the rest being nickel, and the second A 2 alloy powder contains 12% chromium. 18% cobalt, 3% molybdenum, 4% titanium, 5% aluminum, 0.011% boron, 0.05% zirconium and 0.003% carbon, the rest being nickel.

Les poudres d'alliage A1 et d'alliage A2 ont chacune une granulométrie comprise entre 50 et 300 w.The powders of alloy A 1 and of alloy A 2 each have a particle size between 50 and 300 w.

On mélange ensuite des volumes identiques de poudre d'alliage A1 et de poudre d'alliage A2 pendant trente minutes, puis on introduit le mélange de poudres dans un moule en céramique ou en métal réalisé, par exemple, par un procédé tel que le moulage en cire perdue, le schoopage ou tout autre procédé permettant la réalisation de moules simples ou complexes, à parois d'épaisseur comprise entre 1 et 2 mm, suffisamment résistantes pour être manipulées. Ce moule comporte à sa partie supérieure une masselotte cylindrique particulière qui permet d'ajouter à la partie supérieure du moule une quantité supplémentaire du mélange de poudre.Then identical volumes of powder of alloy A 1 and of powder of alloy A 2 are mixed for thirty minutes, then the mixture of powders is introduced into a ceramic or metal mold produced, for example, by a process such as lost wax molding, schooping or any other process allowing the production of simple or complex molds, with walls of thickness between 1 and 2 mm, sufficiently resistant to be handled. 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 the powder mixture.

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 du mélange de poudres.The mold is then placed inside a heating device, by inserting between the walls of the mold and the device a refractory metal powder having a low sinterability, at the temperature chosen for sintering the powder mixture.

On porte ensuite le moule contenant le mélange de poudres à une température d'environ 1 290 °C, en réalisant le chauffage du moule rempli de poudres très rapidement, par exemple en augmentant sa température de 1 000 °C par heure. On maintient ensuite le moule à la température choisie de 1 290°C, sous une pression uniaxiale de 50 à 100-bars, pendant une durée d'environ soixante minutes pour assurer le frittage du mélange de poudre. 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. Après démoulage, les pièces présentent un état de surface parfait avec des grains d'une dimension moyenne de 50 µ.The mold containing the powder mixture is then brought to a temperature of approximately 1290 ° C., by heating the mold filled with powders very quickly, for example by increasing its temperature by 1000 ° C. per hour. The mold is then kept at the chosen temperature of 1290 ° C., under a uniaxial pressure of 50 to 100-bars, for a period of approximately sixty minutes to ensure the sintering of the powder mixture. 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 weight, thus helping to eliminate the porosity in the sintered part. After demolding, the parts have a perfect surface condition with grains with an average size of 50 µ.

Claims (9)

1. Process for the production of alloy bodies by powder metallurgy, characterized in that it comprises preparing, from the constituents of said alloy, a homogeneous mixture of a powder of a first alloy Ai, and a powder of a second alloy A2, said alloys A1 and A2 comprising all the constituents of said alloy but having a different content of at least one alloying element, whereby alloy A1 forms a liquid phase at a temperature T1 which is lower than the temperature T2 at which alloy A2 forms a liquid phase, and sintering the mixture of said powders under pressure at a temperature between T1 and T2, holding the mixture at said temperature for at least one hour.
2. Process according to claim 1, characterized in that the said alloy is selected from the group comprising nickel-based alloys and iron-based alloys.
3. Process according to either of claims 1 and 2, characterized in that the alloying element is selected from the group comprising carbon, boron and zirconium.
4. Process according to claim 1, characterized in that alloy A1 is a nickel alloy comprising 12 % of chromium, 18 % of cobalt, 3 % of molybdenum, 4 % of titanium, 5 % of aluminium, 0.011 % of boron, 0.05 % of zirconium and 0.2 % of carbon, the remainder being nickel, and in that alloy A2 is a nickel alloy comprising 12 % of chromium, 18 % of cobalt, 3 % of molydenum, 4 % of titanium, 5 % of aluminium, 0.011 % of boron, 0.05 % of zirconium and 0.003% of carbon, the remainder being nickel.
5. Process according to any one of claims 1 to 4, characterized in that at least one of said powders is prepared by rapidly cooling liquid droplets which have been formed from a cylindrical ingot of said alloy by raising to fusion temperature the end surface of said ingot while it is rotated around its axis, whereby molten alloy is ejected from the end surface of the ingot under the action of centrifugal force.
6. Process according to claim 4, characterized in that said mixture of powders is sintered at a temperature of around 1 290 °C and under a pressure of around 100 bars.
7. Process according to any one of claims 1 to 6, characterized in that said powder comprises substantially equal volumes of powdered alloy A1 and powdered alloy A2.
8. Process according to any one of claims 1 to 7, characterized in that sintering of said powder is brought about by heating said powder so as to attain sintering temperature as rapidly as possible.
9. Process according to claim 8, characterized in that said powder is heated so that its temperature is increased at a rate of 1 000 to 10 000 °C per hour.
EP79400302A 1978-05-16 1979-05-14 Process for producing alloy articles by powder metallurgy Expired EP0005668B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7814432A FR2425906A1 (en) 1978-05-16 1978-05-16 METHOD OF MANUFACTURING ALLOY PARTS BY POWDER METALLURGY
FR7814432 1978-05-16

Publications (2)

Publication Number Publication Date
EP0005668A1 EP0005668A1 (en) 1979-11-28
EP0005668B1 true EP0005668B1 (en) 1984-11-28

Family

ID=9208274

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79400302A Expired EP0005668B1 (en) 1978-05-16 1979-05-14 Process for producing alloy articles by powder metallurgy

Country Status (4)

Country Link
EP (1) EP0005668B1 (en)
JP (1) JPS54150309A (en)
DE (1) DE2967309D1 (en)
FR (1) FR2425906A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU561663B2 (en) * 1982-05-28 1987-05-14 General Electric Company Homogeneous superalloy powder mixture for the repair of nickel and cobalt superalloy articles
US4381944A (en) * 1982-05-28 1983-05-03 General Electric Company Superalloy article repair method and alloy powder mixture
FR2610856B1 (en) * 1987-02-18 1990-04-13 Snecma PROCESS FOR ASSEMBLING PARTS IN NICKEL-BASED SUPERALLOYS BY LIQUID SINTERING AND HOT ISOSTATIC COMPACTION
JP4146178B2 (en) * 2001-07-24 2008-09-03 三菱重工業株式会社 Ni-based sintered alloy
JP5384079B2 (en) * 2008-10-29 2014-01-08 Ｎｔｎ株式会社 Sintered bearing

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR949279A (en) * 1940-03-07 1949-08-25 Gen Motors Corp Improved process for manufacturing porous metal objects and resulting products
FR968581A (en) * 1948-06-30 1950-11-30 Boehler & Co Ag Geb Process for the production of sintered steel alloys
GB888274A (en) * 1959-03-19 1962-01-31 Gen Electric Co Ltd Improvements in or relating to the manufacture of sintered alloy bodies
FR1263847A (en) * 1960-04-14 1961-06-19 Birmingham Small Arms Co Ltd Improvements in powder metallurgy
US4008844A (en) * 1975-01-06 1977-02-22 United Technologies Corporation Method of repairing surface defects using metallic filler material
GB1535409A (en) * 1976-09-25 1978-12-13 Ford Motor Co Master alloy powders
US4130422A (en) * 1977-06-16 1978-12-19 The United States Of America As Represented By The United States Department Of Energy Copper-base alloy for liquid phase sintering of ferrous powders

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Pulvermetallurgie, Sinter- und Verbundwerkstoffe, pages 173-177, 122-123, 133-134 *

Also Published As

Publication number Publication date
EP0005668A1 (en) 1979-11-28
JPS6312133B2 (en) 1988-03-17
FR2425906A1 (en) 1979-12-14
JPS54150309A (en) 1979-11-26
FR2425906B1 (en) 1982-10-22
DE2967309D1 (en) 1985-01-10

Similar Documents

Publication Publication Date Title
EP1131177B1 (en) Method for making self-brazing components using powder metallurgy
EP3077141B1 (en) Method for producing a part by selective melting of powder
EP3298173B1 (en) Composition for manufacturing parts from titanium aluminide by powder sintering, and manufacturing method using such a composition
FR3083479A1 (en) PROCESS FOR PRODUCING AN ALUMINUM ALLOY PART
FR2557148A1 (en) PROCESS FOR INCREASING THE FORGEABILITY OF A NICKEL-BASED SUPERALLIAGE ARTICLE
EP1728586B1 (en) Superalloy powder
CA2583140A1 (en) Nickel-based alloy
CA2431574C (en) Metallic material susceptible to wear by abrasion; parts, housing; procedure for fabricating such material
FR2512837A1 (en) MONOCRYSTAL SUPER-NICKEL ARTICLES BASED ON NICKEL
FR2914204A1 (en) METAL MOLDING PROCESS BY INJECTION FOR APPLICATION TO BIMETALLIC MATERIALS AND PROFILE-DRAWING
EP3860787A1 (en) Process for manufacturing an aluminum alloy part
EP3860788A1 (en) Process for manufacturing an aluminum alloy part
EP3821049A1 (en) Process for manufacturing an aluminum alloy part
EP1371742B1 (en) Dry and self lubricant material,mechanical pieces made of a such material and its method of fabrication
EP3924124A1 (en) Method for manufacturing an aluminum alloy part
WO2020002813A1 (en) Process for manufacturing an aluminum alloy part
EP0005668B1 (en) Process for producing alloy articles by powder metallurgy
EP0024984B1 (en) Process of making titanium alloy articles by powder metallurgy
FR2548937A1 (en) PROCESS AND APPARATUS FOR MANUFACTURING POWDER ALLOY
EP3810817A1 (en) Process for manufacturing an aluminum alloy part
CH619005A5 (en)
FR2557146A1 (en) HEAT TREATMENT BEFORE HOT ISOSTATIC COMPRESSION OF SUPERALLY MOLDED PIECES
FR2541151A1 (en) PROCESS FOR CONSOLIDATING A METAL OR CERAMIC MASS
BE1004281A6 (en) Method for producing a thin wire made of a fragile metallic material
WO2023161577A1 (en) Alloy powder, method for manufacturing a part based on said alloy and resulting part

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE GB SE

17P Request for examination filed
RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: COMMISSARIAT A L'ENERGIE ATOMIQUE ETABLISSEMENT DE

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): DE GB SE

REF Corresponds to:

Ref document number: 2967309

Country of ref document: DE

Date of ref document: 19850110

PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

26 Opposition filed

Opponent name: SINTOOL AKTIEBOLAG

Effective date: 19850809

RAP2 Party data changed (patent owner data changed or rights of a patent transferred)

Owner name: COMMISSARIAT A L'ENERGIE ATOMIQUE ETABLISSEMENT DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19890514

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19890515

PLBN Opposition rejected

Free format text: ORIGINAL CODE: 0009273

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: OPPOSITION REJECTED

27O Opposition rejected

Effective date: 19890619

GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19900201

EUG Se: european patent has lapsed

Ref document number: 79400302.0

Effective date: 19900412