Nickel-based alloy

Abstract

The present invention relates to a nickel-based alloy comprising, by mass percentage: - 4.0 to 15.7% cobalt; - 15.3 to 19.5% chromium; - 1.6 to 5.45% molybdenum; - 1.65 to 2.5% aluminum; - 2.8 to 4.3% titanium; - 0.01 to 0.10% carbon; - 0.003 to 0.02% boron; and - 0.01 to 0.10% zirconium. The present invention also relates to a method for manufacturing a part from the nickel-based alloy, the method comprising: - the production of a billet having the composition of the nickel-based alloy; - the shaping of the part; and - the heat treatment of the part. Abstract figure: Fig. 1

Description

Title of the invention: Nickel-based alloy Field of invention

[0001] The present invention relates to nickel-based alloys. More particularly, the present invention relates to nickel-based alloys specifically designed for an application such as a turbine casing for an aeronautical engine. State of the art

[0002] The ACARE objectives in line with the European Union's Green Deal for Europe, as well as the requirements for reducing ownership costs imposed by aircraft manufacturers, require engine manufacturers to significantly increase the performance of new-generation turbojets, including a significant reduction in specific consumption. This translates into a need to improve engine efficiency by reducing ventilation of hot parts. Consequently, materials will have to withstand increasingly hot operating temperatures.

[0003] For example, in the case of a low-pressure turbine casing, certain zones are subjected to both fatigue and finishing stresses at very high temperatures, the target of which is 800°C with peaks at 850°C for new-generation engines. However, fatigue life is favored by a fine grain size (around 10 according to the ASTM El 12 standard, subsequently abbreviated to ASTM), whereas the best finishing resistances are obtained on coarse-grained microstructures (around 0 ASTM). Thus, a compromise is required between these two opposing properties.

[0004] Today, the main alloys known for aeronautical turbine casing applications are Inconel 718, 718 Plus, and Waspaloy. Their maximum operating temperatures are respectively of the order of 650 °C, 704 °C and 750 °C. Beyond this, their mechanical properties drop due to a softening of their microstructure. These alloys are therefore not designed to withstand temperatures of the order of 800 °C over long periods.

[0005] Other alloys derived from powder metallurgy make it possible to achieve these high operating temperatures; for example, the alloy described in document EP 1 840 232 Bl. However, this alloy contains more than 43% vol. of y' precipitates and its ductility is not sufficient to envisage forming by ring rolling, a technique used for the manufacture of parts such as turbine casings for aeronautical engines. The upper limit commonly accepted at present is in fact around 40% of y' precipitates.

[0006] This is why Waspaloy, an alloy containing 25% vol. of y' precipitates (of which the nominal combination is in mass percentages Cr 18.00-21.00, Co 12.00-15.00, Mo 3.50-5.00, Al 1.20-1.60, Ti 2.75-3.25, B 0.003-0.01, C 0.02-0.10, Zr 0.02-0.08, Fe 0-2.00, Mn 0-0.10, Si 0-0.15, P 0-0.015, S 0-0.015 and Cu 0-0.10), is currently the one that allows achieving the best compromise between fatigue life and high temperature finishing resistance. This compromise is ensured by obtaining an intermediate grain size (between 2 and 6 ASTM) over the entire part. But again, this alloy was not designed to withstand an operating temperature of 800°C for very long periods.

[0007] Some alloys with 36% vol. of y' precipitates such as FAD730TM or Rene65 could have better properties than Waspaloy, but they do not currently allow an intermediate and homogeneous grain size to be achieved on large parts. Their grain size, which is only controlled by the populations of primary y' precipitates, in fact increases very quickly when the temperature exceeds the y' solvus. Avoiding this excessive growth in grain size would require controlling the heat treatment temperature to the nearest degree over the entire part, which is not achievable in an industrial furnace.

[0008] Thus, at present, there is no alloy which combines better hot resistance than Waspaloy, the ability to be shaped by circular rolling, and the ability to achieve a homogeneous intermediate grain size throughout the part by heat treatment to ensure the compromise between the resistance to finishing and the fatigue life necessary for the intended application.

[0009] There is therefore a need to have a new alloy which can meet the need to increase the operating temperature of the part, while maintaining a manufacturing method by circular rolling and without degrading the fatigue life compared to Waspaloy. Summary of the invention

[0010] Thus, one of the objectives of the present invention is to overcome at least one of the drawbacks mentioned above.

[0011] For this, the present invention proposes a nickel-based alloy, comprising in mass percentage: - 4.0 to 15.7% cobalt; - 15.3 to 19.5% chromium; - 1.6 to 5.45% molybdenum; - 1.65 to 2.5% aluminum; - 2.8 to 4.3% titanium; - 0.01 to 0.10% carbon; - 0.003 to 0.02% boron; and - 0.01 to 0.10% zirconium.

[0012] Other optional and non-limiting features are as follows.

[0013] The nickel-based alloy may comprise in mass percentage: - 0.02 to 0.06% carbon; - 0.005 to 0.01% boron; and - 0.02 to 0.06% zirconium.

[0014] The nickel-based alloy may comprise in mass percentage: - 1.65 to 2.10% of aluminum; and - 2.8 to 3.45% titanium.

[0015] The nickel-based alloy may comprise in mass percentage: - 4.0 to 13.2% cobalt; - 1.80 to 2.30% aluminum; and - 3.5 to 4.0% titanium.

[0016] The nickel-based alloy may comprise in mass percentage: - 4.0 to 11.0% cobalt; - 2.0 to 2.50% aluminum; and - 4.05 to 4.4% titanium.

[0017] The nickel-based alloy may comprise 6.0% by mass or less of iron, preferably 4.0% by mass or less.

[0018] The nickel-based alloy may comprise 6.3% by mass or less of tungsten.

[0019] The nickel-based alloy may comprise 0.4% by mass or less of niobium.

[0020] Furthermore, the present invention provides a method for treating such an alloy comprising: - the manufacture of a billet whose composition is that of the nickel-based alloy; - the shaping of the part; and - heat treatment of the part.

[0021] Other optional and non-limiting features are as follows.

[0022] The manufacture of the billet may comprise: - the production of an ingot, preferably by melting materials; and - the conversion of the ingot into billets, preferably by cutting the ingot and then forging.

[0023] The shaping of the part may include: - forging the billet, preferably by crushing; - rolling of the forged billet, preferably by circular rolling.

[0024] The heat treatment of the part may comprise at least one treatment from: - a solution treatment of the supersolvus y' type, preferably at a temperature su- 10 to 40 °C above the solvus y'; and - a subsolvus y' type solution, preferably at a temperature 10 to 40°C lower than the solvus y'.

[0025] The heat treatment may further comprise: - precipitation tempering of M23C6 type carbides, preferably by heating to a temperature between 825 and 870°C; and - optionally a stabilization income of the populations of precipitates y', preferably at a temperature between 760 and 825 °C.

[0026] The present invention also provides an aeronautical part made of the alloy described above, in particular a turbine casing.

[0027] The nickel-based alloys according to the invention are suitable for the manufacture of parts intended to withstand temperatures of the order of 800°C in the hottest parts thereof and temperature peaks of up to 850°C, while maintaining good fatigue resistance throughout.

[0028] This compromise is made possible by controlling the grain size through heat treatment and forging, which makes it possible to obtain an intermediate grain size of type 2 to 6 ASTM. The alloy is also suitable for production by vacuum casting and shaping by ring rolling, techniques which make it possible to limit manufacturing costs compared to other methods such as powder metallurgy or direct manufacturing. Brief description of the figures

[0029] Other objectives, characteristics and advantages will appear on reading the description with reference to the drawings presented below.

[0030] [Fig. 1] is a diagram showing the steps of the method of manufacturing a part from a nickel-based alloy according to the invention.

[0031] [Fig.2] is a diagram showing an example of sub-steps of manufacturing the billet of the method according to the invention.

[0032] [Fig.3] is a diagram showing an example of ingot making sub-steps of the billet making step.

[0033] [Fig.4] is a diagram showing an example of sub-steps of ingot to billet conversion of the billet manufacturing step.

[0034] [Fig.5] is a diagram showing an example of sub-steps in the shaping of the part of the method according to the invention.

[0035] [Fig.6] is a diagram showing a first example of sub-steps of the heat treatment of the process according to the invention.

[0036] [Fig.7] is a diagram showing a second example of sub-steps of the heat treatment of the process according to the invention.

[0037] [Fig.8] is a diagram showing a third example of sub-steps of the heat treatment of the process according to the invention.

[0038] [Fig.9] is a diagram showing the grain boundaries and carbide precipitates in an alloy according to the invention after treatment according to the treatment method of one of Figures 1 to 8. Detailed description

[0039] A nickel-based alloy according to the present invention is described below. Throughout the following, the composition of the alloy will always be given as a mass percentage.

[0040] The composition of such an alloy is presented in Table 1 below. Nickel is not specified. Generally, the amount of nickel represents the balance to reach 100%. Furthermore, like any alloy composition, it is not technically possible to avoid residual impurities. Thus, although not mentioned in the compositions presented in the present description, certain elements may be present in trace form. Those skilled in the art will be able to recognize whether an element is present in trace form or whether it has been added deliberately. Indeed, it is recognized that elements in trace form do not confer any particular property on the alloy or alter any of the properties of the alloy.

[0041] [Tables 1] Elements Co Cr Mo Al Ti CB Zr Minimum 4.0 15.3 1.6 1.65 2.8 0.01 0.003 0.01 Maximum 15.7 19.5 5.45 2.5 4.3 0.10 0.02 0.10

[0042] Thus, the present alloy comprises the elements cobalt, aluminum and titanium which are intended to form a hardening precipitation y' of ordered structure Ll2 and composition (Ni,Co)3(Al,Ti).

[0043] Furthermore, cobalt contributes to the reinforcement of the mechanical resistance when hot by solid solution hardening of the matrix y and makes it possible to control the stability domains of the carbides of interest MC (M = Ti, Mo) and M23C6 (M = Cr, Mo).

[0044] The chromium content helps in particular to promote the alloy's resistance to oxidation while limiting the precipitation of TCP phases (Topologically Close Pack phases, also known as Frank-Kasper phases) which are embrittling. In addition, chromium contributes to the formation of M23C6 type carbides.

[0045] Molybdenum contributes to the hot mechanical strengthening of the alloy. Its content has been optimized to maximize this strengthening while limiting the precipitation of TCP phases of type o or q considered to be embrittling. The TCP phase of type o is an intermetallic compound having no defined stoichiometric composition and having an electron / atom ratio of 6.2 to 7. It is a primitive unit cell of 30 atoms. The p-type TCP phase has an ideal stoichiometry A6B7. In addition, this element is used in the composition of MC and M23C6 type carbides. MC type carbides are intended to control grain size by anchoring grain boundaries during y' supersolvus treatment. Furthermore, as a first approximation, TCP phases all have the same effect, namely a reduction in the ductility of the alloy by creating potential crack initiation sites. In addition, the formation of TCP phases also contributes to reducing the solid solution strengthening of the matrix because it pumps out some of the atoms of the addition elements.

[0046] Titanium participates in the formation of MC type carbides.

[0047] Carbon is present to control grain growth through the precipitation of MC carbides, and to enhance the hot strength of grain boundaries by forming M23C6 carbides.

[0048] The elements boron and zirconium also make it possible to strengthen the strength of grain boundaries over the entire operating temperature range, in particular up to 850°C.

[0049] The alloy may further comprise 6.0% by mass or less of iron, or even 4.0% by mass or less. Iron is an inexpensive element and makes it possible to reduce the density of the alloy as well as its cost. Furthermore, taking into account an iron content when searching for a suitable composition for the intended applications makes it possible to recycle iron-containing alloys for the production of the nickel-based alloy of the invention and consequently to broaden the range of usable recycled resources.

[0050] The alloy may further comprise 6.3% by mass or less of tungsten. Tungsten, in addition to or as a substitute for molybdenum, makes it possible to improve the hot mechanical behavior of the alloy, in particular by solid solution hardening of the y matrix. The added quantity of molybdenum and tungsten in the alloy in atomic percentage may also be between 2% and 5%. This avoids promoting the precipitation of the TCP phases. In this case, in the formula of M23C6 type carbides, M=Cr, Mo, W.

[0051] The alloy may further comprise 0.4% by mass or less of niobium. When the alloy comprises niobium, the ordered structure L12 is of composition (Ni,Co)3(Al,Ti,Nb) instead of (Ni,Co)3(Al,Ti). Taking into account a niobium content when searching for a suitable composition for the intended applications makes it possible to recycle alloys containing niobium for the production of the nickel-based alloy of the invention and consequently to broaden the range of usable recycled resources. The upper limit of the range, i.e. 0.4%, allows preferential stabilization of titanium carbides over niobium carbides.

[0052] Thus, the composition of the alloy according to the invention is preferably according to the Table 2, with nickel making the balance.

[0053] [Tables2] Elem. Co Cr Mo Al Ti CB Zr Fe W Nb Min. 4.0 15.3 1.6 1.65 2.8 0.01 0.003 0.01 0 0 0 Max. 15.7 19.5 5.45 2.5 4.3 0.10 0.02 0.10 6.0 6.3 0.4

[0054] Such an alloy has a higher hot strength than Waspaloy, in particular thanks to a higher molar fraction of y' precipitates. Thus, thanks to such a composition, this molar fraction is greater than 28%, in particular between 28 and 40%. In addition, it limits the molar fraction of y' precipitates to 40%. Furthermore, the solvus temperature of the y' precipitates is limited to 1120 °C. This makes it easier to shape the alloy by ring rolling.

[0055] This composition also ensures that the sum of the atomic percentages of the elements Al, Ti and Nb is between 7 and 10 at%; which makes it possible to obtain a molar fraction of y' phases between 28% and 40%. In addition, it ensures that the atomic ratio between the element Al on the one hand and the elements Ti and Nb on the other hand (Al / (Ti+Nb)) is between 0.85 and 1.2, thus promoting the precipitation of the y' phase compared to the q-Ni3Ti phase, which is undesirable from the point of view of mechanical properties. In other words, the Ti content is optimized in the y' phase, which maximizes the hot mechanical strengthening of the alloy, while avoiding promoting the formation of the q phase to the detriment of the y' phase.

[0056] This composition induces the precipitation of carbides on the grain boundaries, in particular M23C6 type carbides, which reinforces the hot finishing resistance of the alloy. In particular, the carbides have a discrete distribution at the grain boundaries. They generally have a nodular shape of size less than 5 μm, advantageously less than 1 μm. The discrete distribution at the grain boundaries is made possible by the combination of the composition with an adequate heat treatment described below.

[0057] The quantity of M23C6 carbides may be between 0.4 and 1 mol%, advantageously between 0.5 and 0.75 mol%. This makes it possible to obtain both a population of carbides sufficient to ensure the desired hardening and to avoid saturation of the grain boundaries. Indeed, saturation of the grain boundaries promotes undesired intragranular precipitation.

[0058] Furthermore, the solvus of M23C6 type carbides meets the criterion: (solvus y' — solvus M23C6) > 40 °C.

[0059] Compliance with this criterion allows the performance of a subsolvus heat treatment y' without risking the precipitation of M23C6 type carbides at a temperature above 870°C. Indeed, beyond this temperature, the precipitation of M23 C6 type carbides risks occurring preferentially in the form of films or platelets on the grain boundaries; which is detrimental to resistance to crack propagation.

[0060] Furthermore, the composition ensures solvus of the M23C6 type carbides above 900°C. Thus, the re-solution of the carbides during temperature peaks above 850°C during operation can be avoided, this ultimately making it possible to avoid degradation of the mechanical strength.

[0061] Furthermore, the alloy has an intermediate grain size between 2 and 6 ASTM; which represents a good compromise between the resistance to hot finishing favored by a coarse grain size, and the fatigue resistance favored by a fine grain size.

[0062] This intermediate grain size is notably obtained thanks to the presence of a population of controlled MC-type carbides, which makes it possible to limit the coarsening of the grains during forging and during a heat treatment at a temperature above the y' solvus. These carbides generally have a nodular, sometimes angular, shape in the presence of trace nitrogen, and a size of less than 5 μm. Preferably, the molar quantity of MC-type carbides is between 0.1 and 0.3% at a temperature above the y' phase solvus, for example at a y' solvus temperature + 40°C.

[0063] The presence of MC type carbides allows the anchoring of grain boundaries 2 on MC type carbides 3 during heat treatment ([Fig.9]); which limits grain growth to the targeted value between 2 and 6 ASTM.

[0064] The molar fraction of MC type carbides limited to 0.3% makes it possible to avoid the degradation of the fatigue life via the formation of coarser carbides and carbonitrides (i.e. those with a size greater than 5 μm) which is inherent in production by casting and forging.

[0065] Another way to limit the formation of coarse carbides is to have a solvus temperature of the MC type carbides lower than the solidus of the alloy; which is made possible by the composition.

[0066] A preferred composition is according to the following table 3, or also table 4 taking into account the quantities of Fe, W and Nb.

[0067] [Tables3] Elements Co Cr Mo Al Ti CB Zr Minimum 4.0 15.3 1.6 1.65 2.8 0.02 0.005 0.02 Maximum 15.7 19.5 5.45 2.5 4.3 0.06 0.01 0.06

[0068] [Tables4] Elem. Co Cr Mo Al Ti CB Zr Fe W Nb Min. 4.0 15.3 1.6 1.65 2.8 0.02 0.005 0.02 0 0 0 Max. 15.7 19.5 5.45 2.5 4.3 0.06 0.01 0.06 6.0 6.3 0.4

[0069] These compositions ensure that the sum of the atomic percentages of the elements Al, Ti and Nb is between 7 and 8.25 at.%.

[0070] Another preferred composition is according to the following table 5, or even table 6 taking into account the quantities of Fe, W and Nb.

[0071] [Tables5] Elements Co Cr Mo Al Ti CB Zr Minimum 4.0 15.3 1.6 1.80 3.5 0.02 0.005 0.02 Maximum 13.2 19.5 5.45 2.30 4.0 0.06 0.01 0.06

[0072] [Tableauxô] Elem. Co Cr Mo Al Ti CB Zr Fe W Nb Min. 4.0 15.3 1.6 1.65 2.8 0.02 0.005 0.02 0 0 0 Max. 13.2 19.5 5.45 2.5 4.3 0.06 0.01 0.06 6.0 6.3 0.4

[0073] These compositions ensure that the sum of the atomic percentages of the elements Al, Ti and Nb is between 8.5 and 9 at.%.

[0074] Yet another preferred composition is according to the following table 7, or even table 8 taking into account the quantities of Fe, W and Nb.

[0075] [Tables7] Elements Co Cr Mo Al Ti CB Zr Minimum 4.0 15.3 1.6 2.0 4.05 0.02 0.005 0.02 Maximum 11.0 19.5 5.45 2.5 4.4 0.06 0.01 0.06

[0076] [Tables8] Elem. Co Cr Mo Al Ti CB Zr Fe W Nb Min. 4.0 15.3 1.6 2.0 4.05 0.02 0.005 0.02 0 0 0 Max. 11.0 19.5 5.45 2.5 4.4 0.06 0.01 0.06 4.0 6.3 0.4

[0077] These compositions ensure that the sum of the atomic percentages of the elements Al, Ti and Nb is between 9.25 and 10 at.%. Furthermore, they correspond to the compositions giving the highest molar contents of y' precipitates, up to 40%.

[0078] A method of manufacturing a part from a nickel-based alloy as described above is described below with reference to Figures 1 to 8.

[0079] This method comprises the manufacture 100 of a billet whose composition is that of the nickel-based alloy, the shaping 200 of the part, and the heat treatment 300 of the part ([Fig. 1]).

[0080] The manufacture 100 of the billet may in particular comprise the production 110 of an ingot and the conversion 120 of the ingot into billets ([Fig.2]). The production 110 of the ingot may be carried out by the melting 111 of materials chosen so as to obtain the composition of the nickel-based alloy described above ([Fig.3]). This first stage of production of the ingot may be carried out in particular by vacuum induction melting (better known by the English acronym VIM for Vacuum Induction Melting). The preparation 110 of the ingot may further comprise one or more remelts 112. For example, this step comprises electroslag remelting (better known by the English acronym ESR for Electroslag Remelting) and / or vacuum arc remelting (better known by the English acronym VAR for Vacuum-Arc Remelting) ([Fig. 3]). These additional steps make it possible to improve the inclusion cleanliness of the ingot and to minimize macrosegregations.

[0081] The conversion 120 of the ingot into a billet can be carried out by forging after cutting 121 of the ingot, in particular by successive crushing 122 and drawing 123 of the nickel-based alloy to refine the solidification structure of the nickel-based alloy ([Fig.4]).

[0082] The shaping 200 of the part may comprise the forging 210 of the billet, in particular by crushing the nickel-based alloy forming the billet. The shaping of the part may also comprise rolling 220 after forging, in particular ring rolling. ([Fig.5]).

[0083] The heat treatment 300 of the part notably comprises at least one treatment among a solution treatment of the supersolvus y' type 310 and ... subsolvus type solution y' 320 (figures 6 to 8).

[0084] The supersolvus y' 310 type solution allows the growth of the grains to a desired size and in particular between 2 and 6 ASTM, for example 4 ASTM. For example, the supersolvus y' 310 type solution is carried out by heating to a temperature 10 to 40 °C higher than the solvus y', in particular for a duration of between 1 and 8 h.

[0085] The solution treatment of the subsolvus y' 320 type makes it possible to refine the size of the precipitates y' and to improve the mechanical strength of the alloy. This solution treatment is followed by quenching. For example, the solution treatment of the subsolvus y' 320 type is carried out by heating to a temperature 10 to 40 °C below the solvus y', in particular for a period of between 1 and 8 h. The solution treatment of the subsolvus y' 320 type can be carried out directly after the shaping 200 of the part when the desired grain size is already reached during forging.

[0086] The heat treatment 300 of the part may further comprise a precipitation tempering 330 of the M23C6 type carbides, in particular after the supersolvus y' 310 and / or subsolvus y' 320 solutioning(s). For example, this precipitation tempering 330 of the M23C6 type carbides is carried out by heating to a temperature of between 825°C and 870°C, preferably between 840°C and 860°C, for example approximately 850°C, in particular for 4 to 8 h.

[0087] The heat treatment 300 of the part may further comprise a stabilization tempering 340 of the populations of precipitates y', in particular at a temperature close to the targeted operating temperature, for example between 760°C and 825°C ([Fig.6]), preferably between 790°C and 810°C, for example approximately 800°C, typically after the precipitation tempering 330. For example, this stabilization tempering 340 is carried out by heating between 760 and 825°C, in particular for 4 to 16 h.

[0088] Thus, the heat treatment of the part may in particular include the following combinations (using the discriminating number of the references 310, 320, 330 and 340): 1+3, 1+4, 2+3, 2+4, 1+2+3, 1+2+4, 1+3+4, 2+3+4, 1+2+3+4. Examples

[0089] Table 9 gives the mass composition of twenty-four examples according to the present invention (Ex. 1 to Ex. 24) and of one comparative example (Ex.C 1). Table 10 gives the properties for these examples.

[0090] [Tables9] Élém. Co Cr Mo Al Ti C Zr B Fe W Nb Ex. 1 12,5 17,4 4,65 1,90 3,38 0,030 0,05 0,006 0 0 0 Ex. 2 8,3 17,5 4,67 2,03 3,81 0,040 0,05 0,006 0 0 0 Ex. 3 10,2 15,3 4,55 1,98 3,72 0,030 0,05 0,006 0 3,17 0 Ex. 4 6,3 19,5 2,57 2,05 3,85 0,040 0,05 0,006 0 0 0 Ex. 5 15,6 19,3 3,40 1,67 2,97 0,030 0,05 0,006 0 0 0 Ex. 6 8,4 15,7 3,84 2,40 4,26 0,030 0,05 0,006 0 0 0 Ex. 7 15,5 15,5 5,45 1,65 3,35 0,030 0,05 0,006 0 0 0 Ex. 8 6,3 15,8 2,99 2,17 3,84 0,030 0,05 0,006 5,98 0 0 Ex. 9 8,3 15,5 1,68 2,12 4,19 0,030 0,05 0,006 0 3,22 0 Ex. 10 10,1 15,3 1,64 1,84 3,68 0,030 0,05 0,006 0 6,27 0 Ex. 11 4,0 15,8 2,99 2,17 3,50 0,030 0,05 0,006 3 0 0,40 Ex. 12 12,1 16,8 1,60 1,65 2,85 0,030 0,05 0,006 1,90 6,26 0 Ex. 13 12,5 15,7 3,40 2,03 3,39 0,032 0,05 0,006 0 0 0 Ex. 14 15,7 17,5 3,40 1,91 3,39 0,030 0,05 0,006 0 0 0 Ex. 15 12,0 17,0 4,00 1,70 2,80 0,035 0,05 0,006 3 4 0 Ex. 16 12,0 18,0 5,00 2,00 3,50 0,025 0,05 0,006 1 1 0 Ex. 17 8,4 15,7 2,98 2,01 2,97 0,053 0,05 0,006 0 0 0 Ex.18 12.3 15.4 3.75 2.11 3.74 0.021 0.05 0.006 3.88 3.19 0 Ex. 19 8.4 15.7 4.67 2.27 4.24 0.030 0.05 0.006 0 0 0 Ex. 20 4.2 15.6 3.40 1.79 3.39 0.030 0.05 0.006 4.0 0 0 . 8Z / 0 0 0 900'0 £0'0 0£0'0 t9'£ t6'l OÇ't ÇÇÇI O'HI 0 0 0 900'0 £0'0 0£0'0 0£'t iVl 0'l 8£'Z £'8I £'9 •x'3 06 8£'Z £'8I £'9 •x'3 0 0£0'0 ££'£ 86'l £'ÇI U •X3 0 8I'£ £6'l 900'0 £0'0 0£0'0 ££'£ £8'I t£'£ £'ÇI rs •x3 0 0 £6'£ 900'0 £0'£ 8i9£0'\0'0 The

[0091] [TablelO] PI P2 P3 P4 P5 P6 P7 P8 P9 Ex. 1 1,00 8,0 0,62 1058 956 102 0,16 1248 1295 Ex. 2 0,94 8,8 0,74 1080 995 85 0,16 1271 1286 Ex. 3 0,94 8,8 0,63 1075 956 119 0,16 1260 1283 Ex. 4 0,94 8,8 0,75 1081 1022 59 0,16 1267 1288 Ex. 5 1,00 7,0 0,62 1030 935 95 0,19 1258 1299 Ex. 6 1,00 10,0 0,63 1106 988 118 0,12 1254 1291 Ex. 7 0,88 7,5 0,57 1033 893 140 0,18 1245 1298 Ex. 8 1,00 9,0 0,60 1059 950 109 0,15 1266 1290 Ex. 9 0,90 9,5 0,62 1088 960 128 0,14 1261 1289 Ex. 10 0,89 8,5 0,61 1060 933 127 0,17 1266 1282 Ex. 11 1,04 8,9 0,58 1060 910 150 0,18 1281 1310 Ex. 12 1,03 7,1 0,61 1023 926 97 0,19 1252 1278 Ex. 13 1,06 8,3 0,57 1050 926 124 0,13 1204 1313 Ex. 14 1,00 8,0 0,61 1054 925 129 0,19 1282 1295 Ex. 15 1,08 7,1 0,62 1020 932 88 0,20 1254 1280 Ex. 16 1,01 8,4 0,50 1074 983 91 0,11 1227 1284 Ex. 17 1,20 7,7 1,00 1020 950 70 0,25 1199 1324 Ex. 18 1,00 9,0 0,41 1073 920 153 0,12 1260 1264 Ex. 19 0,95 9,8 0,63 1102 985 117 0,13 1255 1287 Ex. 20 0,94 7,8 0,61 1025 957 68 0,12 1159 1311 Ex.21 1.00 8.0 0.62 1042 923 119 0.18 1254 1297 Ex. 22 0.89 8.5 0.63 1061 950 111 0.17 1259 1284 Ex. 23 0.94 8.8 0.64 1066 992 74 0.12 1206 1290 Ex. 24 1.00 10.0 0.56 1111 1033 78 0.10 1261 1282 Ex.C 1 0.85 9.1 0 1079 838 241 0.22 1302 1299 .

[0092] Where P1 is the atomic ratio Al / (Ti+Nb); P2 is the sum of the atomic percentages of the elements Al, Ti and Nb; P3 is the molar percentage of the M23C6 type carbides determined at 850 °C; P4 is the solvus y' (°C); P5 is the solvus of the M23C6 type carbides (°C); P6 is the difference between the solvus y' and the solvus of the M type carbides 23C6 (°C); P7 is the mole percentage of MC-type carbides, 40 °C above the solvus temperature y'; P8 is the solvus of MC-type carbides (°C); and P9 is the solidus (°C).

Claims

Claims

1. Nickel-based alloy, comprising in mass percentage: - 4.0 to 15.7% of cobalt; - 15.3 to 19.5% of chromium; - 1.6 to 5.45% of molybdenum; - 1.65 to 2.5% of aluminum; - 2.8 to 4.3% of titanium; - 0.01 to 0.10% of carbon; - 0.003 to 0.02% of boron; - 0.01 to 0.10% of zirconium; - 0 to 6.0% of iron; - 0 to 6.3% of tungsten; and - 0 to 0.4% of niobium, the nickel representing the balance to arrive at 100%.

2. Nickel-based alloy according to claim 1, comprising in mass percentage: - 0.02 to 0.06% of carbon; - 0.005 to 0.01% of boron; and - 0.02 to 0.06% of zirconium.

3. Nickel-based alloy according to claim 2, comprising in mass percentage: - 1.65 to 2.10% of aluminum; and - 2.8 to 3.45% of titanium.

4. Nickel-based alloy according to claim 2, comprising in mass percentage: - 4.0 to 13.2% of cobalt; - 1.80 to 2.30% of aluminum; and - 3.5 to 4.0% of titanium.

5. Nickel-based alloy according to claim 2, comprising in mass percentage: - 4.0 to 11.0% of cobalt; - 2.0 to 2.50% of aluminum; and - 4.05 to 4.4% of titanium.

6. A method of manufacturing a part from a nickel-based alloy according to one of claims 1 to 5, the method comprising: - manufacturing a billet whose composition is that of the nickel-based alloy; - shaping the part; and - heat treatment of the part.

7. Method according to claim 6, in which the heat treatment of the part comprises at least one treatment from: - a supersolvus y' type solution treatment, preferably at a temperature 10 to 40 °C higher than the solvus y'; and - a subsolvus y' type solution treatment, preferably at a temperature 10 to 40 °C lower than the solvus y'.

8. Method according to one of claims 6 to 7, in which the heat treatment may further comprise: - precipitation tempering of the M23C6 type carbides, preferably by heating to a temperature between 825 and 870°C; and - optionally stabilization tempering of the populations of precipitates y', preferably at a temperature between 760 and 825°C.

9. Aeronautical part made of an alloy according to one of claims 1 to 5, in particular a turbine casing.

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