Diffusion brazing process for pieces of superalloys
AssigneeSociete Nationale d'Etude et de Construction de Moteurs d'Aviation "S.N.E.C.M.A."
InventorJacques Lesgourgues
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Abstract
A diffusion brazing process for superalloy parts is performed on the one hand by the interposition between the pieces to be joined of a joining layer having a composition close to that of the parts and containing a "fluxing" element, which renders it more readily meltable, and on the other hand, a heat treatment effecting the brazing by the melting of the joining layer and its resolidification, by the diffusion of the flux. The process of the invention is characterized, particularly in view of permitting the use of a joining layer of a greater thickness than that of the layers used in the known diffusion brazing processes, in that said joining layer consists of a mixture of a superalloy powder and an alloy powder containing the flux.
Claims8
A process for diffusion brazing a layer of material between faces defined by an article formed by nickel or cobalt base superalloys comprising the steps of:
- (a) forming the layer of material from a mixture having properties identical to the superalloys and formed of at least two alloy powders in appreciably unequal proportions, the two alloy powders comprising (i) a base powder of NK17CDAT (Astroloy) forming approximately 75% by weight of the mixture and (ii) an addition powder forming approximately 25% by weight of the mixture, the addition powder being a Ni B Cr alloy such that the liquidus temperature of the addition powder is lower than the solidus temperature of the base powder and the article;
- (b) placing the layer of material between the faces of the article;
- (c) heating the assembly to a temperature sufficient to melt the addition powder, but not the base powder or the article, the melted addition powder being retained in the base powder by capillary action;
- and,
- (d) subjecting the assembly to a diffusion brazing heat treatment.
A process for diffusion brazing a layer of material between faces defined by an article formed by nickel or cobalt base superalloys comprising the steps of:
- (a) forming the layer of material from a mixture having properties identical to the superalloys and formed of at least two alloy powders in appreciabely unequal proportions, the two alloy powders comprising (i) a base powder of NK17CDAT (Astroloy) forming approximately 75% by weight of the mixture and (ii) an addition powder forming approximately 25% by weight of the mixture, the addition powder being an alloy of Ni Co Si B, such that the liquidus temperature of the addition powder is lower than the solidus temperature of the base powder and the article;
- (b) placing the layer of material between the faces of the article;
- (c) heating the assembly to a temperature sufficient to melt the addition powder, but not the base powder or the article, the melted addition powder being retained in the base powder by capillary action;
- and,
- (d) subjecting the assembly to a diffusion brazing heat treatment.
Dependencies are inferred from the claim text.