An alloy for manufacturing a tool intended for manufacturing aircraft parts made of composite materials

Abstract

The present invention relates to an alloy for manufacturing a tool intended for manufacturing an aircraft part made of a composite material, comprising, by mass, 32.6% ≦ Ni ≦ 38.0%, 0.80% ≦ Co ≦ 4.20% [provided that Co ≧ -1.00 × Ni% + 36.80% (where Ni% refers to the Ni content in mass percent in the alloy), and Co ≦ -1.63 × Ni% + 62.72% (where Ni% refers to the Ni content in mass percent in the alloy)], 1.0% ≦ Ti ≦ 2.0%, 0.0010% ≦ rare earths ≦ 0.0500%, 0.10% ≦ Si ≦ 0.35%, 0.15% ≦ Mn ≦ 0.60%, 0.005% ≦ C ≦ 0.04%, with the balance being iron and impurities resulting from the production process.

Description

Technical Field

[0001] The present disclosure relates to tools intended for the manufacture of aircraft parts made of composite materials, in particular alloys for manufacturing molds or mold parts.

Background Art

[0002] By seeking a compromise between mass and mechanical properties in the aircraft industry, an increasing number of aircraft parts made of composite materials, in particular structural parts or functional components such as wings or fuselages, are being produced. These composite materials generally include a polymer matrix in which reinforcing fibers are embedded. For example, the polymer matrix is formed of a thermoplastic resin, in particular an epoxy, polyester, vinyl ester, polyamide or phenolic resin. The reinforcing fibers are selected, for example, from among glass, carbon, Kevlar® (registered trademark), aluminum, or titanium fibers. In some cases, the fibers are woven for the purpose of further improving the mechanical properties of the part.

[0003] In the production of these parts, the starting material is generally a prepreg, i.e., a composite material in the form of strips containing reinforcing fibers embedded in a polymer matrix. The parts are manufactured from this starting material using one of the following two methods. (a) The following continuous process: a. A step of depositing the starting material as a continuous layer on a convex or concave metal mold to obtain a layup on the metal mold; b. A step of subjecting the layup to a vacuum bag treatment to remove air bubbles and consolidating the layup into a mold of a more complex or less complex shape; c. A step of curing the polymer matrix of the composite material by heat-treating the assembly including the mold and the layup in an autoclave under pressure and at a temperature of 120°C to 180°C for several hundred minutes including lamination and autoclave curing; (b) Compression molding. This method is similar to method (a), but instead of the autoclave curing process, it involves curing the composite material in a press by hot pressing the layup between a first mold to which the layup is applied and a second mold having a cavity that matches the cavity of the first mold. The hot pressing is carried out at the same temperature and for the same period as those mentioned with respect to method (a).

[0004] Therefore, the tools used to produce aircraft parts from composite materials by the methods described above should ideally have the following characteristics: - Good mechanical strength under the curing temperature of the polymer matrix and the many thermal cycles resulting from the reuse of the tool, - A coefficient of thermal expansion that matches the coefficient of thermal expansion of the composite material being used, - Dimensional stability, - Vacuum tightness.

[0005] Furthermore, this tool should enable production with minimized costs, final mass, production time, etc., especially in terms of manufacturing costs.

[0006] In the production of parts from composite materials containing carbon fibers embedded in an epoxy resin matrix, when the metal alloy from which the tool is made has a coefficient of thermal expansion of 2.2×10 -6 °C -1 ~2.9×10 -6 °C -1 at 20°C to 200°C, the coefficient of thermal expansion of the tool is considered to be compatible with the coefficient of thermal expansion of the composite material being used.

[0007] Invar M93 has a coefficient of thermal expansion suitable for the production of such tools. Furthermore, it also exhibits advantageous characteristics for the said applications, especially in terms of scratch resistance and impact resistance, a longer tool life than non-metal molds, the possibility of obtaining a structure of welded tools or molds by machine, and the machinability of tools having a structure welded by machine.

[0008] For the purpose of reducing production costs and improving productivity related to production tools intended for the above uses, the production of this tool using an additive manufacturing process is required. Additive manufacturing enables the rapid and flexible manufacture of this tool. It also enables the manufacture of tools that can withstand more thermal cycles with limited maintenance.

[0009] To further improve productivity, it is required to achieve a relatively high deposition rate, for example a deposition rate of about 450 cm 3 / hour or more in the additive manufacturing process.

[0010] One way to increase the deposition rate in additive manufacturing is to shorten the time between two consecutive paths of material deposition, also called the inter-pass time in the remainder of this specification. However, the inventors of the present disclosure have found that when manufacturing test walls by wire arc additive manufacturing using Invar M93 wire, shortening the inter-pass time leads to the collapse of these walls due to an increase in the inter-pass temperature. In particular, the inventors observed that at an inter-pass temperature of 600 °C, and thereafter the walls began to show slack. Therefore, the said method cannot manufacture parts of sufficient quality at the target production rate. Summary of the Invention Problems to be Solved by the Invention

[0011] One object of the present invention is to propose an alloy that enables the additive manufacturing of tools intended for the manufacture of aircraft parts from composite materials with improved productivity. Means for Solving the Problems

[0012] For this purpose, the present invention is an alloy for the manufacture of tools intended for the manufacture of aircraft parts made of composite materials, by mass, 32.6% ≦ Ni ≦ 38.0% 0.80% ≦ Co ≦ 4.20% [However, Co ≥ -1.00×Ni% + 36.80% (where Ni% refers to the Ni content in mass percentage in the alloy), Co ≤ -1.63×Ni% + 62.72% (where Ni% refers to the Ni content in mass percentage in the alloy), 1.0% ≤ Ti ≤ 2.0%, 0.0010% ≤ rare earths ≤ 0.0500%, 0.10% ≤ Si ≤ 0.35% 0.15% ≤ Mn ≤ 0.60% 0.005% ≤ C ≤ 0.04% which includes, and the balance is iron and impurities resulting from the production process, regarding the alloy.

[0013] Preferably, the impurities resulting from the production process are, by mass, Ca ≤ 0.0015%, Mg ≤ 0.0035%, Al ≤ 0.0085% O ≤ 0.0025% S ≤ 0.0035% P ≤ 0.0100% B ≤ 0.0005% Mo ≤ 0.1%, Cr ≤ 0.1% Cu ≤ 0.1%, Nb ≤ 0.01% V ≤ 0.01% including.

[0014] Preferably, the rare earths include yttrium, cerium, lanthanum, neodymium, praseodymium, or a mixture thereof.

[0015] The present invention also relates to a filler wire made of the alloy defined above.

[0016] The present invention also relates to a method for manufacturing the filler wire defined above, comprising - a step of preparing a semi-finished product with the alloy defined above, - a step of hot working this semi-finished product to form an intermediate wire, - A step of processing an intermediate wire into a filler wire having a diameter smaller than that of the intermediate wire, including a wire drawing step, and a step relating to a method including

[0017] The present invention also relates to the use of an alloy as defined above for manufacturing at least a part of a tool intended for the manufacture of aircraft parts in composite materials.

[0018] The present invention also relates to a part or a part of a part made of the alloy as defined above.

[0019] According to a specific feature of the part or the part of the part, - The part or the part of the part is obtained by additive manufacturing with metal, - The part is a tool, particularly a mold, intended for the manufacture of aircraft parts in composite materials.

[0020] The present invention also relates to a method for manufacturing a part or a part of a part, including a step of producing the part or the part of the part by a metal additive manufacturing process using, as a filler material, a filler wire made of the alloy as defined above and / or a powder of the alloy as defined above.

[0021] According to a specific feature of the manufacturing method, - The additive manufacturing process is selected from wire arc, wire laser, wire electron beam, and hybrid additive manufacturing methods combining wire arc and powder laser or wire arc and wire laser technologies.

[0022] The present invention also relates to the use of the filler wire as defined above as a filler wire in a metal additive manufacturing process.

[0023] The present invention also relates to a metal powder made of the alloy as defined above.

[0024] The present invention also relates to a method for producing the metal powder as defined above, the method comprising the step of providing a filler wire as defined above, and the step of obtaining a metal powder by plasma spraying the filler wire.

[0025] The present invention will be better understood by reading the following description, which is given by way of example only, and by referring to the accompanying drawings.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0027] The alloy of the present invention, by mass, 32.6% ≦ Ni ≦ 38.0% 0.80% ≦ Co ≦ 4.20% [However, Co ≧ -1.00 × Ni% + 36.80% (where Ni% refers to the Ni content in mass percent in the alloy), and Co ≦ -1.63 × Ni% + 62.72% (where Ni% refers to the Ni content in mass percent in the alloy)], 1.0% ≦ Ti ≦ 2.0%, 0.0010% ≦ rare earths ≦ 0.0500%, 0.10% ≦ Si ≦ 0.35%, 0.15% ≦ Mn ≦ 0.60%, 0.005% ≦ C ≦ 0.04% and the balance is iron and impurities resulting from the production process.

[0028] Impurities resulting from the production process mean elements contained in the raw materials used to prepare the alloy or derived from the equipment used in this preparation, such as furnace refractories. These residual elements have no metallurgical effect on the alloy.

[0029] Impurities resulting from the production process are, in particular, by mass, Ca ≤ 0.0015%, Mg ≤ 0.0035%, Al ≤ 0.0085%, O ≤ 0.0025%, S ≤ 0.0035%, P ≤ 0.0100%, B ≤ 0.0005%, Mo ≤ 0.1%, Cr ≤ 0.1%, Cu ≤ 0.1%, Nb ≤ 0.01%, V ≤ 0.01% and include.

[0030] More specifically, the contents of sulfur, phosphorus, oxygen, boron, magnesium, aluminum and calcium are preferably limited to the above upper limits in order to prevent a decrease in the weldability of the alloy. In particular, restricting the contents of magnesium, aluminum, calcium and oxygen to the specified contents above prevents a decrease in the stability of the electric arc in the arc mode, especially in additive manufacturing. Restricting the contents of sulfur, phosphorus and boron to the above contents prevents a decrease in the resistance to hot cracking of the parts made of this alloy.

[0031] Finally, the contents of molybdenum, chromium, copper, niobium and vanadium are preferably limited to the above contents in order to prevent a decrease in the thermal expansion coefficient of the alloy.

[0032] The above alloy is an Invar-type alloy.

[0033] The alloy of the present invention is an austenitic alloy at a temperature equal to room temperature (about 20°C).

[0034] The average coefficient of thermal expansion α of the alloy of the present invention at 20°C to 200°C 20℃_200℃ is 2.2×10 -6 °C -1 ~2.9×10 -6 °C -1 . The average coefficient of thermal expansion at 20°C to 200°C within this range is particularly advantageous when the alloy of the present invention is used to produce tools intended for the manufacture of aircraft parts from composite materials, and especially when it includes an epoxy resin matrix in which reinforcing fibers are embedded according to the above-described method. Said coefficient can ensure the compatibility in terms of thermal expansion between the tool made of the above-described alloy and the composite material used for manufacturing aircraft parts. Without compatibility of the average coefficient of thermal expansion between the tool and the part, there is a risk of distorting or deforming the part during manufacture due to the expansion of the part relative to the tool, or of forming stresses within the part during cooling after the curing treatment. Furthermore, the composite material can separate from the tool during heating, generating drips that leave the fibers uncoated, resulting in defective parts. Thus, with the alloy of the present invention, it is possible to obtain parts, in particular parts such as tools or parts of tools for producing aircraft parts, that include composite materials for aircraft applications, especially composite materials including an epoxy resin matrix in which carbon reinforcing fibers are embedded, and the parts satisfy the theoretical dimensions, the fibers are completely protected by the resin, and there are no residual stresses.

[0035] Also, the average coefficient of thermal expansion α of 2.2×10 -6 °C -1 ~2.9×10 -6 °C -1 from 20°C to 200°C 20℃_200℃ ensures good dimensional stability.

[0036] Furthermore, the alloy of the present invention makes it possible to obtain parts such as tools or parts of tools for producing aircraft parts, which have the following. - Good mechanical strength under the curing temperature of the polymer matrix and the many thermal cycles resulting from the reuse of the tool, and - Vacuum tightness.

[0037] In the alloy of the present invention, the nickel content is 32.6% to 38.0% by mass. When the nickel content is less than 32.6% by mass, there is a risk of martensitic transformation at a temperature close to room temperature, and there is a risk that the alloy will no longer be austenite at room temperature, which is harmful to its dimensional stability. When the nickel content exceeds 38.0% by mass, the thermal expansion coefficient of the alloy becomes excessively high, and the dimensional stability of the alloy is at risk.

[0038] In the present invention, the cobalt content is 0.80% to 4.20% by mass and further satisfies the following conditions: Co ≥ -1.00×Ni% + 36.80% and Co ≤ -1.63×Ni% + 62.72%. In these inequalities, Ni% refers to the nickel content by mass in the alloy, and Co indicates the cobalt content by mass% in the alloy.

[0039] The range of the allowable cobalt content expressed in mass percent as a function of the nickel content expressed in mass percent is shown in FIG. 1. In this figure, - Line C_sup has the equation: Co = 4.20%, - Line C_inf has the equation: Co = 0.80%, - Line C1 has the equation: Co = -1.00×Ni% + 36.80%, - Line C2 has the equation: Co = -1.63×Ni% + 62.72%.

[0040] In this figure, the range of the present invention corresponds to the range delimited by lines C1, C2, C_inf and C_sup.

[0041] At a cobalt content within this range, an average thermal expansion coefficient of 2.2×10 -6 °C -1 to 2.9×10 -6 °C -1 can be obtained at 20°C to 200°C.

[0042] When the cobalt content is more than 4.20% by mass (corresponding to the cobalt content above the line C_sup in FIG. 1), the average coefficient of thermal expansion at 20°C to 200°C has a risk of falling below the lower limit of 2.2×10 -6 °C -1 , which is desirable for the above-mentioned applications, i.e., the manufacture of tools intended for the manufacture of aircraft parts. Also, in this case, under work hardening treatment, and particularly through plastic deformation during wire drawing for example, the risk of martensitic transformation increases, which increases the cost price of the manufacturing method through wire drawing and requires intermediate austenite annealing to an intermediate wire diameter of approximately 2 mm for example.

[0043] When the cobalt content is less than 0.80% by mass (corresponding to the cobalt content below the line C_inf in FIG. 1), the average coefficient of thermal expansion at 20°C to 200°C has a risk of exceeding the upper limit of 2.9×10 -6 °C -1 desired for the above-mentioned applications.

[0044] When the cobalt content is below the line C1, i.e., Co < -1.00×Ni% + 36.80%, the average coefficient of thermal expansion at 20°C to 200°C has a risk of exceeding the upper limit of 2.9×10 -6 °C -1 desired for the above-mentioned applications.

[0045] When the cobalt content is above the line C2, i.e., Co > -1.63×Ni% + 62.72%, the average coefficient of thermal expansion at 20°C to 200°C has a risk of exceeding the upper limit of 2.9×10 -6 °C -1 desired for the above-mentioned applications.

[0046] In the alloy of the present invention, with a titanium content of 1.0% to 2.0% by mass, good resistance to the collapse of the molten pool during the additive manufacturing of parts made of the alloy of the present invention through wire arc additive manufacturing can be obtained, and thus in particular the formation of drips in the parts is prevented.

[0047] When the titanium content is less than 1.0% by mass, the resistance of the molten pool to collapse during the additive manufacturing of parts with the alloys of the present invention, especially via wire arc additive manufacturing, is insufficient, and high production speeds, especially deposition rates of 450 cm 3 / hour or more, produce undesirable drips.

[0048] When the titanium content is more than 2.0% by mass, the average coefficient of thermal expansion from 20 °C to 200 °C has a risk of exceeding the upper limit of 2.9×10 -6 °C -1 desired for the above applications.

[0049] In the alloys of the present invention, the rare earth content is 0.0010% to 0.0500%. The addition of rare earths at the indicated content strengthens the role of titanium, thereby being able to improve the resistance of the molten pool to collapse, especially during the additive manufacturing of parts with the alloys of the present invention via wire arc additive manufacturing.

[0050] The rare earths are particularly selected from among yttrium, cerium, lanthanum, neodymium and praseodymium, or mixtures thereof.

[0051] In one example, the rare earth is yttrium.

[0052] In one variant, the rare earths include a mixture of cerium and lanthanum, for example obtained from mischmetal. In particular, the rare earths are a mixture of cerium and lanthanum.

[0053] In the alloys of the present invention, silicon, manganese and carbon are added to desulfurize and deoxidize the alloy. Their content by mass is selected within the following ranges: 0.10% ≤ Si ≤ 0.35% 0.15% ≤ Mn ≤ 0.60% 0.005% ≤ C ≤ 0.04%

[0054] When the content of silicon and / or manganese is higher than the limits indicated above, the coefficient of thermal expansion is 2.9×10 desired for the above applications-6 °C -1 has a risk of exceeding the upper limit of.

[0055] A carbon content exceeding 0.04% has a risk of causing problems of high-temperature cracking during solidification due to the precipitation of titanium carbide, and thus a risk of deteriorating the behavior during the solidification of the weld metal.

[0056] The alloy of the present invention is advantageous. It enables the production via additive manufacturing of high-quality tools or parts of tools intended for the production of aircraft parts in a high-productivity, simple and flexible manner, especially in composite materials containing an epoxy resin matrix in which carbon fibers are embedded as reinforcing fibers. The alloy has the desirable properties of the above-described alloys, in particular, a coefficient of thermal expansion of 2.2×10 -6 °C -1 ~2.9×10 -6 °C -1 at 20°C to 100°C, which provides sufficient compatibility between the tool and the part to be manufactured, and good resistance to the collapse of the molten pool during the additive manufacturing of the part, enabling the production of parts of good quality at a high production rate, especially a deposition rate of 450 cm 3 / hour or more.

[0057] The alloy of the present invention can be prepared using any suitable method known to those skilled in the art.

[0058] For example, in a first step, the starting materials are placed in an electric arc furnace. These starting materials are melted in the electric arc furnace, and vacuum oxygen decarburization (VOD) using a new vacuum oxygen decarburization (VOD) vessel is carried out using the usual method to obtain the following: - Decarburization via oxygen injection and vacuum pumping (a few mbar); - Deoxidation and desulfurization with respect to the lime-based slag; and - Adjustment of the silicon content.

[0059] The present invention also relates to a filler wire made of an alloy having the composition defined above.

[0060] The filler wire is particularly suitable for use as a filler wire in a metal additive manufacturing process.

[0061] The additive manufacturing process is, for example, an additive manufacturing process using an electric arc, a laser beam and / or an electron beam as an energy source for obtaining the fusion of the filler wire.

[0062] The additive manufacturing process is particularly an additive manufacturing process known as directed energy deposition. In this process, the filler material is deposited particularly via a nozzle and is immediately fused by concentrated thermal energy, particularly by a laser beam, an electron beam and / or an electric arc.

[0063] For example, the additive manufacturing process is a wire arc (wire arc additive manufacturing or WAAM process), a wire laser or an electron beam wire (electron beam freeform fabrication or electron beam additive manufacturing) process, or a hybrid additive manufacturing process combining the technologies of wire arc and powder laser or wire arc and wire laser.

[0064] In the case of a hybrid wire arc and powder laser process, the powder used has the same composition as the wire.

[0065] The powder having a particle size after sieving of 20 μm to 150 μm is obtained, for example, from the filler wire of the present invention using a plasma spraying technique. Preferably, the filler wire used for manufacturing the powder has a diameter of about 3 mm.

[0066] The particle size of the powder is determined particularly using the following method. Under ultrasonic vibration, a stainless steel sieve is used to divide a batch of powder into several particle size distributions. The analysis of the particle size distribution of the sieved powder is carried out according to the standard ASTM B214-07. By sieving, five classes of particle sizes less than 20 μm - 20 μm to 45 μm - 45 μm to 75 μm - 75 μm to 105 μm - over 105 μm can be obtained.

[0067] The technology of plasma spraying to produce powder from wire is known per se and will not be described in more detail accordingly.

[0068] The present invention also relates to a method for manufacturing a filler wire with the above-described alloy.

[0069] This method includes, in a first step, providing a semi-finished product made of this alloy. The alloy is cast into an ingot, or directly cast in the form of a billet, particularly by means of rotary continuous casting. Therefore, the semi-finished product obtained after this step is preferably an ingot or a billet, having a diameter of, for example, 130 to 230 mm, more specifically about 150 mm.

[0070] The semi-finished product is deformed by hot working to form an intermediate wire.

[0071] Particularly, in this hot working step, the semi-finished product, particularly the ingot or the billet, is reheated in a gas furnace to a temperature of, for example, 1180 °C to 1220 °C.

[0072] Next, they are subjected to hot rough rolling to reduce their cross-section, and a square cross-section having sides of, for example, about 100 mm to 200 mm is imparted to them. Thereby, a semi-finished product with a reduced cross-section is obtained. The length of this semi-finished product with a reduced cross-section is 10 m to 20 m.

[0073] The semi-finished product with a reduced cross-section is hot worked again at a temperature of 950 °C to 1150 °C to obtain an intermediate wire. The intermediate wire may particularly be a wire rod. This has a diameter of, for example, 5 mm to 21 mm, particularly about 5.5 mm. Advantageously, in this step, the intermediate wire is produced by hot rolling in a wire rod mill.

[0074] Optionally, the intermediate wire is then subjected to solution annealing after heat treatment in a gas furnace at a temperature of 1150 °C to 1220 °C for a period of 60 minutes to 120 minutes.

[0075] The intermediate wire is then stripped and wound onto a spool.

[0076] Optionally, the intermediate wire thus obtained is drawn in a known type of wire drawing facility to obtain a filler wire. This filler wire has a smaller diameter than the starting wire. In particular, this has a diameter of 0.5 mm to 3.5 mm. Advantageously, this is 0.8 mm to 2.4 mm.

[0077] The wire drawing process includes one or more wire drawing passes, depending on the final diameter to be reached, and preferably involves annealing between two consecutive wire drawing passes. This annealing is carried out inline, for example, at a temperature in the region of 1150 °C, in a reducing atmosphere.

[0078] Subsequent to the wire drawing process, preferably, the surface of the drawn wire is cleaned and the wire is wound helically onto a spool.

[0079] The wire drawing passes are cold passes.

[0080] Any other method known to those skilled in the art for preparing the alloy of the present invention and for manufacturing the final product with this alloy can be used for this purpose.

[0081] The present invention also relates to a method for manufacturing a part or a part of part 1 made of the above-described alloy, as schematically shown in FIG. 2, - a step of preparing a filler wire with the above-described alloy; - a step of manufacturing part 1 or a part of the part by a metal additive manufacturing process using, as a filler material, the filler wire made of the above-described alloy and / or the powder of the above-described alloy and includes.

[0082] Component 1 or a part of the component is preferably a tool or a part of a tool intended for use in the manufacture of aircraft components made of composite materials, the composite materials comprising, in particular, an epoxy resin matrix in which reinforcing fibers are embedded in the form of carbon fibers. In particular, component 1 is a mold or a part of a mold intended for use in the manufacture of aircraft components made of composite materials, the composite materials comprising, in particular, an epoxy resin matrix in which reinforcing fibers are embedded in the form of carbon fibers. For example, component 1 defines a molding surface of a tool intended for use in the manufacture of aircraft components made of composite materials and, optionally, also includes a support structure for the molding surface.

[0083] The additive manufacturing process is, for example, an additive manufacturing using an electric arc, a laser beam and / or an electron beam as an energy source for obtaining the fusion of a filler material.

[0084] In particular, the additive manufacturing process is an additive manufacturing process known as directed energy deposition. In this method, the filler material is deposited, in particular, by a nozzle and is immediately fused by concentrated thermal energy, in particular, by a laser beam, an electron beam and / or an electric arc.

[0085] For example, the additive manufacturing process is a wire arc, a wire laser or an electron beam wire (electron beam freeform fabrication or electron beam additive manufacturing) process, or a hybrid additive manufacturing process combining wire arc and powder laser or wire arc and wire laser technologies.

[0086] In the case of a hybrid additive manufacturing process combining wire arc and powder laser or wire arc and wire laser technologies, the powder and the filler wire are made of the above-described alloy.

[0087] The above-described additive manufacturing processes are known per se and will not be described in detail.

[0088] However, in the present invention, the additive manufacturing process includes several passes, each pass corresponding to the formation of a layer of the part 1 or part of the part to be produced, and the time between two consecutive passes is defined by the minimum time required for the tool, in particular the filler material fusion tool, such as a laser beam, an electron beam and / or an electric arc, to return to the start of the deposition zone.

[0089] Considering the above-mentioned advantageous properties of the alloys of the present invention, this manufacturing method enables the flexible production of high-quality parts 1 or parts of parts with high productivity, in particular a deposition rate of more than 450 cm 3 / hour or more.

[0090] In particular, in the hybrid wire arc and powder laser processes, when the filler material contains powder, before the production of the part 1 or part of the part, the method also includes the step of preparing the powder of the above-mentioned alloy. This powder having a particle size after sieving of 20 μm to 150 μm is produced, for example, by plasma spraying from a wire made of the above-mentioned alloy, and the wire has a diameter of particularly about 3 mm.

[0091] The plasma spraying process is known per se and will not be described in detail.

[0092] The present invention also relates to a part 1 or part of a part made of the above-mentioned alloy obtained by metal additive manufacturing.

[0093] The part 1 or part of the part is preferably a tool or part of a tool intended for the production of aircraft parts made of composite materials, and the composite materials particularly include an epoxy resin matrix in which reinforcing fibers are embedded in the form of carbon fibers. In particular, the part 1 is a mold or part of a mold intended for the production of aircraft parts made of composite materials, and the composite materials particularly include an epoxy resin matrix in which reinforcing fibers are embedded in the form of carbon fibers. For example, the part 1 defines a molding surface of a tool intended for use in the production of aircraft parts made of composite materials and also optionally includes a support structure for the molding surface.

[0094] The metal additive manufacturing process particularly uses, as filler materials, filler wires made of the above-described alloy and / or powders made of the above-described alloy.

[0095] For example, the additive manufacturing process is an additive manufacturing process that uses an electric arc, a laser beam, and / or an electron beam as an energy source for the fusion of the filler material.

[0096] In particular, the additive manufacturing process is a method known as directed energy deposition. In this method, the filler material is deposited, in particular, by a nozzle and immediately fused by concentrated thermal energy, in particular, by a laser beam, an electron beam, and / or an electric arc.

[0097] For example, the additive manufacturing process is a wire arc, a wire laser, or an electron beam wire (electron beam freeform fabrication or electron beam additive manufacturing) process, or a hybrid additive manufacturing process that combines the technologies of wire arc and powder laser or wire arc and wire laser.

[0098] When a hybrid additive manufacturing process is used by combining the technologies of wire arc and powder laser, or wire arc and wire laser, the powder and the filler wire are made of the above-described alloy.

[0099] A part 1 or a part of a part obtained by a metal additive manufacturing process remains solidified. Therefore, it has a solidification microstructure typical of the nickel alloy under consideration, which typically includes columnar dendritic crystals obtained by epitaxial growth with respect to each other, and the orientation thereof depends on the width and height of the fabricated metal wall. Further, the part 1 obtained by the additive manufacturing process exhibits a series of overlapping solidified layers due to this process. Each layer obtained by the solidification of the deposited molten metal droplets melts the skin of the previous layer to create metallurgical continuity and thus reheats the rest of the underlying layer. The reheating temperature decreases as the layer under consideration moves away from the zone where melting and solidification are taking place. This particular microstructure can be seen under metallographic observation of the metallographic analysis section of the part 1.

[0100] Therefore, a part 1 or a part of a part obtained by a metal additive manufacturing process can be distinguished from parts obtained by other methods, in particular parts obtained by conventional metallurgical methods that produce a recrystallized structure with homogeneous grains.

Example

[0101] Test The inventors prepared, in the laboratory under vacuum, an alloy having the composition as defined above and a comparative alloy having a composition different from that of the above-described composition, and then cast these alloys in the laboratory to obtain a frustoconical ingot having a diameter of 120 mm at the bottom of the cone and a diameter of 60 mm at the tip of the cone. The obtained ingot was hot forged to obtain a bar having a diameter of 100 mm and a length of 500 mm, which was surface machined to remove scale, and forged with a rotary forging machine sold by GFM to produce a bar having a diameter of 30 mm and a length of 3 m. These bars were cold drawn to produce a wire having a diameter of 5.5 mm and a length of 15 m. The cold drawing process included a plurality of consecutive drawing operations and was accompanied by a recrystallization heat treatment at a temperature of 1000 °C for 1 hour between two consecutive drawing operations. After cold drawing, the wire was annealed in a gas furnace at a temperature of 1150 °C for 1 hour, stripped, and finally drawn with an industrial wire drawing machine and wound onto a 15 kg spool to produce an experimental filler wire having a diameter of 1.2 mm.

[0102] This production method has been conventionally used to produce filler wire in the laboratory, and it is possible to obtain a filler wire having the same composition, surface cleanliness, and suitability for use as the filler wire obtained by the method previously described regarding the manufacture of filler wire.

[0103] The respective alloy compositions of the obtained filler wires are shown in Table 1 below.

[0104]

Table 1

[0105] In Table 1 above, the alloys not having the composition of the present invention are underlined.

[0106] In this table, <<->> means that the content of the element considered is at most trace amounts.

[0107] In all of the alloys, the balance consists of iron and impurities resulting from the production process.

[0108] Finally, from these wires, the inventors fabricated walls by a wire arc additive manufacturing process using a Fronius TPS500i welding station and a Yaskawa MH24 robot under the following manufacturing conditions. Gas: Argon + 2.5% CO2; flow rate 18 L / min Process: CMT_Fronius Synergistic effect: INVAR WAAM Wire feed speed: 8.6 m / min Melting speed: 30 cm / min Arc correction: -1.6 Dynamic correction: 6.2 Single weave: amplitude 6 mm; frequency 2 Hz, stop at spots 1 and 3 for 0.4 s Inter-pass pause time: 240 s Pass increment: 2.5 mm Deposition rate: 580 cm 3 / h.

[0109] The fabricated walls obtained had a length of 150 mm, a width of 150 mm, and a height of 70 mm.

[0110] For each alloy, the inventors determined the number of drips occurring during wall fabrication and the average coefficient of thermal expansion of the alloy at 20°C to 200°C.

[0111] The number of drips was visually observed on the walls during fabrication.

[0112] The average coefficient of thermal expansion at 20°C to 200°C was measured as follows. The expansion ΔL of the alloy during heating from 20°C to 200°C was measured, and the average coefficient of thermal expansion α[20°C_200°C] at 20°C to 200°C was calculated using the equation: α[20°C_200°C] = 1 / L0 × ΔL / ΔT (where ΔT = 200°C - 20°C and L0 is the initial length (50 mm) of the test piece).

[0113] Table 2 (Table 2) summarizes the results of tests performed on the wires of alloy numbers 1 to 22 and Invar M93 in Table 1 (Table 1).

[0114]

Table 2

[0115] In the above Table 2 (Table 2), test walls that do not conform to the present invention are underlined.

[0116] Tests conducted by the inventors have shown that walls made from filler wire in Invar M93 exhibit drips. Therefore, this material is not sufficient for the production of tools or parts of tools intended for the manufacture of aircraft components in composite materials with improved productivity, i.e., relatively short inter-pass times as used during the tests.

[0117] Alloy numbers 1 to 4 in the above Table 1 (Table 1) have titanium and / or rare earth contents lower than the lower limit of the range corresponding to the alloys of the present invention. The inventors have found that walls made from wires fabricated with these alloys also exhibit non-zero drip numbers of 7, 5, 3, and 1 respectively. Therefore, these alloys are also not sufficient for the production of tools or parts of tools intended for the manufacture of aircraft components in composite materials with improved productivity.

[0118] Furthermore, it is observed that alloy number 1 has an average coefficient of thermal expansion at 20°C to 200°C lower than the desired lower limit for this application. The inventors are of the opinion that this insufficiently high average coefficient of thermal expansion is due to the titanium content being lower than the lower limit for the alloys of the present invention.

[0119] Alloy number 9 has a titanium content exceeding the upper limit of the corresponding range of the alloys of the present invention. This wall shows no relaxation. On the other hand, this wall has a coefficient of 3.3×10 at 20°C to 200°C -6 °C -1has an average coefficient of thermal expansion, which is too high for the intended applications.

[0120] Alloy numbers 10, 11, 14, and 18 have a cobalt content of less than -1.00×Ni% + 36.80% and / or less than 0.80 mass%. Walls made from wires of these alloys do not show relaxation. However, the average coefficient of thermal expansion of these alloys at 20°C to 200°C is too high for the intended applications.

[0121] Alloy numbers 16 and 21 have a cobalt content exceeding -1.63×Ni% + 62.72%. Walls made from wires of these alloys do not show relaxation. However, the average coefficient of thermal expansion of these alloys at 20°C to 200°C is 3.1×10 -6 °C -1 and 3.5×10 -6 °C -1 respectively, which is too high for the intended applications.

[0122] Alloy number 22 has a cobalt content exceeding 4.20 mass%. Walls made from wires of this alloy do not show relaxation. However, the average coefficient of thermal expansion of this alloy at 20°C to 200°C is 2.0×10 -6 °C -1 which is too low for the intended applications.

[0123] Conversely, walls made from the alloys of the present invention corresponding to composition numbers 5, 6, 7, 8, 12, 13, 15, 17, 19, and 20 do not show relaxation. Furthermore, these alloys have an average coefficient of thermal expansion of 2.2×10 -6 °C -1 to 2.9×10 -6 °C -1 at 20°C to 200°C, and thus enable the production of tools or parts of tools with improved productivity, i.e., for the manufacture of aircraft parts in composite materials with relatively short pass times as used in testing.

Claims

1. An alloy for manufacturing a tool intended for manufacturing an aircraft part made of a composite material, by mass, 32.6% ≤ Ni ≤ 38.0%, 0.80% ≤ Co ≤ 4.20% [provided that Co ≥ -1.00 × Ni% + 36.80% (where Ni% refers to the Ni content in mass percent in the alloy), Co ≤ -1.63 × Ni% + 62.72% (where Ni% refers to the Ni content in mass percent in the alloy)], 1.0% ≤ Ti ≤ 2.0%, 0.0010% ≤ rare earths ≤ 0.0500%, 0.10% ≤ Si ≤ 0.35%, 0.15% ≤ Mn ≤ 0.60%, 0.005% ≤ C ≤ 0.04% and the balance being iron and impurities resulting from the production process, an alloy.

2. Impurities resulting from the production process, by mass, Ca ≤ 0.0015%, Mg ≤ 0.0035%, Al ≤ 0.0085%, O ≤ 0.0025%, S ≤ 0.0035%, P ≤ 0.0100%, B ≤ 0.0005%, Mo ≤ 0.1%, Cr ≤ 0.1%, Cu ≤ 0.1%, Nb ≤ 0.01% V ≤ 0.01% are included, the alloy according to Claim 1.

3. The rare earths include yttrium, cerium, lanthanum, neodymium, praseodymium, or a mixture thereof, the alloy according to Claim 1 or 2.

4. A filler wire made of the alloy according to any one of Claims 1 to 3.

5. A method for manufacturing the filler wire according to Claim 4, comprising - a step of preparing a semi-finished product made of the alloy according to any one of Claims 1 to 3, - a step of hot-working this semi-finished product to form an intermediate wire, - a step of converting the intermediate wire into a filler wire having a diameter smaller than that of the intermediate wire, including a wire drawing step, a method.

6. Use of the alloy according to any one of Claims 1 to 3 for manufacturing at least a part of a tool intended for manufacturing an aircraft part made of a composite material.

7. A part (1) or a part of a part made of the alloy according to any one of Claims 1 to 3.

8. The part (1) or a part of a part according to Claim 7 obtained by additive manufacturing of metal.

9. The part is a tool intended for manufacturing an aircraft part made of a composite material, in particular a mold, the part (1) or a part of a part according to Claim 7 or 8.

10. A method for manufacturing a component or a part of a component, comprising the step of manufacturing the component or the part of the component by means of an additive manufacturing process using, as a filler material, a filler wire made of the alloy according to any one of claims 1 to 3 and / or a powder of the alloy according to any one of claims 1 to 3.

11. The manufacturing method according to claim 10, wherein the additive manufacturing process is selected from a wire arc, a wire laser, a wire electron beam process, and a hybrid additive manufacturing process combining the technologies of a wire arc and a powder laser or a wire arc and a wire laser.

12. Use of the filler wire according to claim 4 as a filler wire for an additive manufacturing process.

13. A metal powder made of the alloy according to any one of claims 1 to 3.

14. A method for manufacturing the metal powder according to claim 13, comprising the step of providing the filler wire according to claim 4 and the step of obtaining the metal powder by plasma spraying the filler wire.

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