WO2024042291A1

WO2024042291A1 - Method for manufacturing an aluminum alloy part

Info

Publication number: WO2024042291A1
Application number: PCT/FR2023/051279
Authority: WO
Inventors: Bechir CHEHAB
Original assignee: C-Tec Constellium Technology Center
Priority date: 2022-08-25
Filing date: 2023-08-18
Publication date: 2024-02-29
Also published as: FR3139018A1

Abstract

A method for manufacturing a part (20) comprising a formation of successive metal layers (201…20n), which are stacked on one another, each layer being formed by depositing a filler metal (15, 25), energy being supplied to the filler metal in such a way that the filler metal melts and, upon solidification, constitutes said layer, the method being characterized in that the filler metal (15, 25) is an aluminum alloy comprising the following alloying elements (in % by weight): - at least one alloying element chosen from: Zr, Hf and Er, in a weight fraction of greater than or equal to 0.30 each and in total; - at least one alloying element chosen from: Cr, V, Ti and Mn, in a weight fraction of greater than 0.50% each and in total; - Fe, in a weight fraction of from 0.10% to 2.50%; - optionally Co, La, Ce, mischmetal, W, Ta, Mo, Nb, Ni, Cu, Ag, Si, Sc, Mg, Zn, Li, Nd, Y, Tm, Lu, Yb, Sr, Ba, Sb, Bi, Ca, P, B, In, Sn and impurities; the remainder being aluminum.

Description

DESCRIPTION

Title: Process for manufacturing an aluminum alloy part

TECHNICAL AREA

The technical field of the invention is a process for manufacturing an aluminum alloy part, using an additive manufacturing technique.

PRIOR ART

Since the 1980s, additive manufacturing techniques have developed. They consist of shaping a part by adding material, which is the opposite of machining techniques, which aim to remove material. Formerly confined to prototyping, additive manufacturing is now operational to mass produce industrial products, including metal parts.

The term “additive manufacturing” is defined according to the French standard XP E67-001 as a “set of processes allowing the manufacture, layer by layer, by adding material, of a physical object from a digital object”. ASTM F2792 (January 2012) also defines additive manufacturing. Different additive manufacturing methods are also defined and described in the ISO/ASTM 17296-1 standard. The use of additive manufacturing to produce an aluminum part, with low porosity, was described in document W02015006447. The application of successive layers is generally carried out by application of a so-called filler material, then melting or sintering of the filler material using an energy source such as a laser beam, electronic beam, plasma torch. or electric arc. Whatever the additive manufacturing method applied, the thickness of each added layer is of the order of a few tens or hundreds of microns.

Other additive manufacturing methods can be used. Let us cite for example, and in a non-limiting manner, the melting or sintering of a filler material taking the form of a powder. This can be laser fusion or sintering. Patent application US20170016096 describes a process for manufacturing a part by localized fusion obtained by exposing a powder to an energy beam of the electron beam or laser beam type, the process also being designated by Anglo-Saxon acronym LPBF, meaning “Laser Powder Bed Fusion” or “Electron Beam Melting” (= fusion by electron beam).

The mechanical properties of aluminum parts obtained by additive manufacturing depend on the alloy forming the filler metal, and more precisely on its composition as well as the heat treatments applied following the implementation of additive manufacturing. The applicant has determined an alloy composition which, used in an additive manufacturing process, makes it possible to obtain parts with remarkable mechanical performance, without it being necessary to carry out heat treatments of the solution and quenching type. .

For aluminum alloys, the maximum electrical or thermal conductivity is generally obtained for pure aluminum. However, pure aluminum suffers from poor mechanical properties, which limits its scope of use. To improve the mechanical strength of pure aluminum, it is possible to increase its content of additive elements. Conversely, to improve the electrical conductivity of an aluminum alloy, it is possible to limit the contents of addition elements other than aluminum. Thus, the variation in the total content of addition elements impacts in an antinomic manner the conductivity and the mechanical resistance of an aluminum alloy. Also, it is difficult to design aluminum alloys having both sufficient thermal conductivity in the raw manufacturing state and sufficient mechanical strength after heat treatment.

According to a variant of the present invention, with a judicious choice of addition elements, the applicant has identified aluminum alloy compositions intended for additive manufacturing processes, in particular LPBF, these compositions make it possible to obtain both , very good processability of parts in the LPBF process, and excellent mechanical performance of parts in service. Good processability of parts in the LPBF process is obtained by combining in the raw manufacturing state, a sufficiently low level of hardness (for example Knoop HK0.05 hardness in the raw manufacturing state less than 140, preferably less than 130 , preferably less than 120) and a sufficiently high thermal or electrical conductivity (for example electrical conductivity in the raw state of manufacture greater than 6 MS/m, preferably greater than 7 MS/m, preferably greater than 8 MS/ m). This combination of hardness and conductivity makes it possible to limit the level of residual stresses of the parts in the raw manufacturing state, which significantly limits the risk of cracking, delamination or distortion, thus significantly improving the processability of the parts in the LPBF process. . The excellent mechanical performance of the parts in service is obtained by maximizing the hardness of the parts after post-manufacturing heat treatment (for example Knoop HK0.05 hardness greater than 70, preferably greater than 80, preferably greater than 90, preferably greater than 100, preferably greater than 114).

Pure aluminum powders can be used as a reductant in solid propellant in aerospace thrusters. Therefore, aluminum powders with more than 97% aluminum are generally considered in some countries as dual-use goods (BDU) requiring export licenses. This classification represents a constraint which can slow down the marketing of certain aluminum powders comprising more than 97% aluminum intended for the additive manufacturing process, such as for example LPBF. It thus appears advantageous for the developed solution to have less than 97% aluminum, that is to say more than 3% of addition elements in total.

According to another variant of the present invention, with a judicious choice of addition elements, the applicant has identified compositions of aluminum alloys intended for additive manufacturing processes, in particular LPBF, these compositions comprising more than 3% d addition elements to the total and allowing good processability of parts in the LPBF process, while maximizing the mechanical performance of the parts in service.

STATEMENT OF THE INVENTION

A first object of the invention is a method of manufacturing a part comprising a formation of successive metal layers, superimposed on each other, each layer being formed by the deposition of a filler metal, the filler metal being subjected to a supply of energy so as to melt and to constitute, by solidifying, said layer, the process being characterized in that the filler metal is an aluminum alloy comprising the following alloy elements in mass percentages:

- at least one alloy element chosen from: Zr, Hf, and Er, according to a mass fraction greater than or equal to 0.30%, preferably 0.30 to 2.50%, preferably 0.40 to 2 .00%, more preferably from 0.40 to 1.80%, even more preferably from 0.50 to 1.60%, even more preferably from 0.60 to 1.50%, even more preferably from 0.70 to 1.40%, even more preferably from 0.80 to 1.30% each and in total;

- at least one alloy element chosen from: Cr, V, Ti and Mn, according to a mass fraction greater than 0.50%, preferably more than 0.50 to 6.00%, preferably from 1.00 to 6.00%, more preferably 1.00 to 5.00%, even more preferably 1.00 to 4.00%, even more preferably 1.00 to 3.00%, each for V, Ti and Mn , and in total; and at a mass fraction of more than 0.50 to 3.00% for Cr;

- optionally at least one alloy element chosen from: Co, La, Ce, mischmetal, W, Ta, Mo and Nb, according to a mass fraction of at least 0.10%, preferably at least 0.25 %, more preferably at least 0.50% each and in total; and according to a mass fraction of less than 5.00%, preferably less than 4.00%, preferably less than 3.00% each; and according to a mass fraction less than 7.00%, preferably less than 6.00%, preferably less than 5.00%, preferably less than 4.00% in total;

- Fe, in a mass fraction of 0.10 to 2.50%, preferably 0.15 to 2.50%, preferably 0.20 to 2.50%, more preferably 0.30 to 2.50 %, even more preferably from 0.50 to 2.50%, even more preferably from 0.75 to 2.25%;

- optionally Ni, in a mass fraction less than 3.00%, preferably less than 2.00%, preferably less than 1.00%, preferably less than 0.50%;

- optionally at least one alloy element chosen from: Cu and Ag, in a mass fraction of 0.10 to 3.00%, preferably 0.10 to 2.00%, preferably 0.10 to 1 .60%, preferably 0.10 to 1.00%, preferably 0.10 to 0.70% each and in total;

- optionally Si, in a mass fraction less than 3.00%, preferably less than 2.00%, preferably less than 1.00%, preferably less than 0.50%; in one embodiment, the Si content is less than 0.30%, preferably less than 0.20%;

- optionally Sc, according to a mass fraction less than 0.80%, preferably less than 0.70%, preferably less than 0.60%, preferably less than 0.50%, preferably less than 0.40%, preferably less than 0.30%;

- optionally Mg, in a mass fraction less than 2.00%, preferably less than 1.00%, preferably less than 0.50%, more preferably less than 0.30%;

- optionally Zn, in a mass fraction less than 2.00%, preferably less than 1.00%, preferably less than 0.50%, more preferably less than 0.30%;

- optionally Li, in a mass fraction less than 2.00%, preferably less than 1.00%, preferably less than 0.50%, more preferably less than 0.30%;

- optionally at least one element chosen from: Nd, Y, Tm, Lu, Yb, Sr, Ba, Sb, Bi, Ca, P, B, In and Sn, according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.50%, preferably less than or equal to 0.30%, more preferably less than or equal to 0.10%, even more preferably less than or equal to 700 ppm each, and less than or equal to 2, 00%, preferably less than or equal to 1.00%, preferably less than or equal to 0.50%, preferably less than or equal to 0.30% in total;

- impurities: < 0.05% individually, and preferably < 0.15% in total; remains aluminum.

Each layer can in particular describe a pattern defined from a digital model.

According to one embodiment, the filler metal takes the form of a powder, exposure to a beam of light or charged particles results in localized melting followed by solidification, so as to form a solid layer. . According to another embodiment, the filler metal comes from a filler wire, exposure to a heat source, for example an electric arc, results in localized melting followed by solidification, so as to form a solid layer.

A second object of the invention is a metal part, obtained by a process according to the first or the second object of the invention. A third object of the invention is a filler material, in particular a filler wire or a powder, intended to be used as filler material for an additive manufacturing process, characterized in that it is made of an aluminum alloy, comprising the following alloy elements (% by weight):

- optionally Mg, with a mass fraction less than 2.00%, preferably less at 1.00%, preferably less than 0.50%, more preferably less than 0.30%;

- impurities: < 0.05% individually, and in total < 0.15%; remains aluminum.

The aluminum alloy forming the filler material may have the characteristics described in connection with the first object of the invention.

The filler material may be in the form of a powder. The powder may be such that at least 80% of the particles composing the powder have an average size in the following range: 5 pm to 200 pm, preferably 5 to 150 pm, preferably 5 to 25 pm, or 20 to 60 pm or from 20 to 80 pm or from 20 to 90 pm or from 20 to 100 pm or from 20 to 110 pm or from 20 to 120 pm.

When the filler material is in the form of a wire, the diameter of the wire can in particular be from 0.5 mm to 3 mm, and preferably from 0.5 mm to 2 mm, and even more preferably ranging from 1 mm to 2 mm.

A fourth object of the invention is the use of a powder or a filler wire as described above and in the rest of the description in a manufacturing process chosen from: fusion by beam of electron beam melting, cold spray, laser fusion deposition, friction additive manufacturing, plasma spark sintering or rotary friction welding, preferably cold spray.

Other advantages and characteristics will emerge more clearly from the following description of particular embodiments of the invention, given by way of non-limiting examples, and represented in the figures listed below.

FIGURES

[Fig. 1] Figure 1 is a diagram illustrating an LPBF type additive manufacturing process. [Fig. 2] Figure 2 is a diagram illustrating a WAAM type additive manufacturing process. [Fig. 3] Figure 3 is a diagram of the wafer after laser reflow used according to the examples.

[Fig. 4] Figure 4 is a schematic of the Knoop hardness test.

PRESENTATION OF SPECIAL MODES OF REALIZATION

In the description, unless otherwise stated:

- the designation of aluminum alloys complies with the nomenclature of The Aluminum Association;

- the contents of chemical elements are designated in % and represent mass fractions. The notation x% - y% means greater than or equal to x% and less than or equal to y%.

By impurities we mean chemical elements present in the alloy unintentionally.

Figure 1 schematizes the operation of an additive manufacturing process of the selective laser fusion type (Laser Powder Bed Fusion or LPBF). The filler metal 15 is in the form of a powder placed on a support 10. An energy source, in this case a laser source 11, emits a laser beam 12. The laser source is coupled to the material contribution by an optical system 13, the movement of which is determined according to a digital model M. The laser beam 12 propagates along a propagation axis Z, and follows a movement along an XY plane, describing a pattern depending on the model digital M. The plane is for example perpendicular to the propagation axis Z. The interaction of the laser beam 12 with the powder 15 generates a selective melting of the latter, followed by solidification, resulting in the formation of a layer 20i... _20n . When a layer has been formed, it is covered with powder of the filler metal and another layer is formed, superimposed on the layer previously made. The thickness of a layer can for example be between 10 and 250 pm, for example 30 pm, or 60 pm, or 80 pm, or 90 pm, or 100 pm, or 110 pm, or 120 pm, or 130 pm , or 140 pm, or 150 pm, or 160 pm, or 170 pm, or 180 pm, or 190 pm, or 200 pm.

An increase in layer thickness can be beneficial to increase productivity during printing and to limit sensitivity to thermal cracking linked to residual stresses during the manufacturing of the part and/or during post-manufacturing heat treatment. An increase in layer thickness can be accompanied by an adaptation of the laser power and the vector gap (distance between two successive laser passes) and the scanning speed of the laser in order to ensure complete fusion of each powder layer in optimal conditions. The layer thickness may for example be from 60 to 250 pm, preferably from 80 to 200 pm, preferably from 90 to 180 pm, preferably from 100 to 180 pm, preferably from 110 to 170 pm, preferably from 120 to 160 p.m. For aluminum alloys, the support 10 or plate can be heated to a preheating temperature T of up to 500°C. The machines currently available on the market generally offer plate heating up to 200°C. The heating temperature of the plate (= preheating temperature T) can be for example approximately 50°C, 100°C, 150°C, 200°C, 250°C, 300°C or 350°C or 400° C or 450°C or 500°C. Heating the plate generally makes it possible to reduce the humidity in the powder bed and also to reduce the residual stresses on the parts being manufactured. The humidity level at the powder bed appears to have a direct effect on the porosity of the final part. Indeed, it seems that the higher the humidity of the powder, the higher the porosity of the final part. It should be noted that heating the plate is one of the existing possibilities for carrying out hot additive manufacturing. However, the present invention cannot be limited to the use of this heating means alone. All other heating means, making it possible to carry out this preheating step, can be used in the context of the present invention to heat and control the temperature, for example an infrared lamp. Thus, the process according to the present invention can be carried out at a preheating temperature T of up to 500°C.

For certain compositions, the inventors have observed that when the preheating temperature Test is less than or equal to 160°C and greater than or equal to 25°C, the parts have better resistance to thermal cracking linked to residual stresses. Preferably, the preheating of the plate and therefore of the powder bed can be carried out at a preheating temperature T less than or equal to 140°C, or, better still, less than or equal to 130°C. The preheating temperature T is higher than the ambient temperature. The preferred preheating temperature ranges T are: 25°C < T < 160°C, preferably 30°C < T < 150°C, preferably 50°C < T < 150°C, preferably 50°C < T < 140°C, preferably 60°C < T < 140°C, preferably 70°C < T < 135°C, preferably 80°C < T < 130°C.

According to an alternative, the preheating temperature T corresponds to the conditions in which effective expansion can be obtained. The preheating temperature range T can then be from 300°C to 500°C, preferably from 300 to 400°C, preferably from 300 to 350°C. It is considered that at this preheating temperature range T, the manufacturing conditions of the part generate fewer residual stresses. According to this alternative, a post-production heat treatment of relaxation, as described below in the present description, is also relevant.

The powder according to the present invention may have at least one of the following characteristics: - Average particle size of 5 pm to 200 pm, preferably of 5 to 150 pm, preferably of 5 to 25 pm, or of 20 to 60 pm, or of 20 to 80 pm, or of 20 to 90 pm, or from 20 to 100 pm, or from 20 to 110 pm, or from 20 to 120 pm. The values given mean that at least 80% of the particles have an average size within the specified range.

- Spherical shape. The sphericity of a powder can for example be determined using a morphogranulometer.

- Good flowability. The flowability of a powder can for example be determined according to the ASTM B213 standard or the ISO 4490:2018 standard. According to ISO 4490:2018, the flow time is preferably less than 50.

- Low porosity, preferably 0 to 5%, more preferably 0 to 2%, even more preferably 0 to 1% by volume. Porosity can in particular be determined by image analysis from optical micrographs or by helium pycnometry (see standard ASTM B923).

- Absence or small quantity (less than 10%, preferably less than 5% by volume) of small particles (1 to 20% of the average size of the powder), called satellites, which stick to larger particles.

The implementation of such a process allows parts to be manufactured at a high yield, which can reach or even exceed 200 cm ³ /h per laser.

Furthermore, the applicant observed that the application of post-fabrication heat treatments such as quenching could induce distortion of the part, due to the sudden variation in temperature. The distortion of the part is generally more significant as its dimensions increase. However, the advantage of an additive manufacturing process is precisely to obtain a part whose shape, after manufacturing, is definitive or almost definitive. The occurrence of significant deformation resulting from post-manufacturing heat treatment should therefore be avoided. By quasi-final, it is understood that finishing machining can be carried out on the part after its manufacture: the part manufactured by additive manufacturing extends according to its final shape, except for finishing machining.

Having noted the above, the applicant sought an alloy composition, forming the filler material, making it possible to obtain acceptable mechanical and electrical or thermal conductivity properties, without requiring the application of subsequent heat treatments. during the formation of the layers, that is to say following the formation of the final part, risking distortion. This includes avoiding heat treatments involving a sudden variation in temperature. Thus, the invention makes it possible to obtain, by additive manufacturing, a part whose mechanical properties, in particular in terms of elastic limit, and conductivity, electrical or thermal, are satisfactory. Depending on the type of additive manufacturing process chosen, the filler material can be in the form of a wire or a powder.

The following elements can be used in aluminum alloy.

Zr, Hf and/or Er:

According to the present invention, at least one alloy element chosen from: Zr, Hf and Er is present in the aluminum alloy in a mass fraction greater than or equal to 0.30%, preferably from 0.30 to 2 .50%, preferably from 0.40 to 2.00%, more preferably from 0.40 to 1.80%, even more preferably from 0.50 to 1.60%, even more preferably from 0.60 to 1, 50%, even more preferably from 0.70 to 1.40%, even more preferably from 0.80 to 1.30% each and in total. Preferably, the mass fraction of at least one alloy element chosen from: Zr, Hf and Er is greater than or equal to 0.30%, or 0.35%, or 0.40%, or 0.45% , or 0.50%, or 0.55%, or 0.60%, or 0.65%, or 0.70% each and in total. Preferably, the mass fraction of at least one alloy element chosen from: Zr, Hf and Er is less than or equal to 2.50%, or 2.40%, or 2.30%, or 2.20%. , or 2.10%, or 2.00%, or 1.90%, or 1.80%, or 1.70%, or 1.60%, or 1.50%, or 1.40%, or 1.30% each and in total.

These elements have high solubility in the as-manufactured state. Their addition can thus significantly lower the conductivity in the raw state. However, the addition of a post-manufacturing heat treatment, for example at a temperature of 300 to 450°C, for periods of 0.5 to 10 hours, can make it possible to significantly lower their solid solution contents by the formation of hardening dispersoids of type AI3X (X= Zr or Hf or Er). The formation of these dispersoids during heat treatment can simultaneously increase the hardness and electrical conductivity compared to the raw state.

These elements can also make it possible to control the granular structure during laser fusion by promoting the appearance of equiaxed grains.

Furthermore, the presence of at least one alloy element chosen from: Zr, Hf and Er in the alloy can confer good processability of the alloy, the term processability corresponding to the Anglo-Saxon designation "processability", qualifying the ability of an alloy to be shaped by an additive manufacturing process. This can result, at the level of a part manufactured by additive manufacturing, in a virtual absence of defects, such as cracking, and low porosity. Cr, V, Ti and/or Mn:

According to the present invention, at least one alloy element chosen from: Cr, V, Ti and Mn is present in the aluminum alloy in a mass fraction greater than 0.50%, preferably more than 0.50 at 6.00%, preferably from 1.00 to 6.00%, more preferably from 1.00 to 5.00%, even more preferably from 1.00 to 4.00%, even more preferably from 1.00 to 3.00%, each for V, Ti and Mn, and in total; and at a mass fraction of more than 0.50 to 3.00% for Cr. Preferably, the mass fraction of at least one alloy element chosen from: Cr, V, Ti and Mn is greater than 0.50%, or greater than or equal to 0.60%, or 0.70%, or 0.80%, or 0.90%, or 1.00% each and in total. Preferably, the mass fraction of at least one alloy element chosen from: Cr, V, Ti and Mn is less than or equal to 6.00%, or 5.50%, or 5.00%, or 4. 50%, or 4.00%, or 3.50%, or 3.00%, or 2.50% or 2.00%, or 1.50%, or 1.00% each and in total.

These elements can make it possible to increase the mechanical strength of the alloy by solid solution and/or by dispersoids which can form during the manufacture of the part or during post-manufacturing heat treatments. But these elements have high solubility in aluminum and have a negative impact on conductivity. The addition of these elements is of interest for alloys targeting certain applications that do not require particular performance in terms of electrical or thermal conductivity but which require high mechanical resistance, such as structural parts, hydraulic blocks, etc. .

Co, La, Ce, mischmetal, W, Ta, Mo and/or Nb:

According to the present invention, at least one alloy element chosen from: Co, La, Ce, mischmetal, W, Ta, Mo and/or Nb may be present in the aluminum alloy in a mass fraction of at least 0.10%, preferably at least 0.25%, more preferably at least 0.50% each and in total; and according to a mass fraction of less than 5.00%, preferably less than 4.00%, preferably less than 3.00% each; and in a mass fraction of less than 7.00%, preferably less than 6.00%, preferably less than 5.00%, preferably less than 4.00% in total. Preferably, the mass fraction of at least one alloy element chosen from: Co, La, Ce, mischmetal, W, Ta, Mo and Nb is greater than or equal to 0.10%, or 0.15%, or 0.20%, or 0.25%, or 0.30%, or 0.35%, or 0.40%, or 0.45%, or 0.50% each and in total. Preferably, the mass fraction of at least one alloy element chosen from: Co, La, Ce, mischmetal, W, Ta, Mo and Nb is less than 5.00%, or 4.50%, or 4. 00%, or 3.50%, or 3.00% each. Preferably, the mass fraction of at least one alloy element chosen from: Co, La, Ce, mischmetal, W, Ta, Mo and Nb is less than 7.00%, or 6.50%, or 6. 00%, or 5.50%, or 5.00%, or 4.50%, or 4.00% in total. These elements can make it possible to increase the mechanical strength of the alloy by solid solution and/or by dispersoids which can form during the manufacture of the part or during post-manufacturing heat treatments. These elements have low solubility in aluminum. Adding these elements can help harden the alloy without having a significant negative impact on conductivity.

Preferably, the aluminum alloy comprises at least one alloy element chosen from Co, La, Ce, mischmetal, W, Ta, Mo and Nb.

Fe:

According to the present invention, the element Fe is present in the aluminum alloy in a mass fraction of 0.10 to 2.50%, preferably 0.15 to 2.50%, preferably 0.20 to 2.50%. 2.50%, more preferably from 0.20 to 2.50%, even more preferably from 0.30 to 2.50%, even more preferably from 0.50 to 2.50%, even more preferably from 0.75 to 2.25%. Preferably, the mass fraction of Fe is greater than or equal to 0.10%, or 0.15%, or 0.20%, or 0.25%, or 0.30%, or 0.35%, or 0 .40%, or 0.45%, or 0.50%, or 0.55%, or 0.60%, or 0.65%, or 0.70%, or 0.75%. Preferably, the mass fraction of Fe is less than or equal to 2.50%, or 2.40%, or 2.30%, or 2.20%, or 2.25%.

This element can make it possible to increase the mechanical strength of the alloy by solid solution and/or by dispersoids which may form during the manufacture of the part or during post-manufacturing heat treatments. This element has low solubility in aluminum. Adding this element can help harden the alloy without having a significant negative impact on conductivity.

Neither :

According to the present invention, the element Ni can be present in the aluminum alloy in a mass fraction less than 3.00%, preferably less than 2.00%, preferably less than 1.00%, preferably less at 0.50%. Preferably, the mass fraction of Ni is greater than 500 ppm, preferably greater than 0.10%, preferably greater than 0.15%, preferably greater than 0.20%, preferably greater than 0.30%, preferably greater than 0.40%.

This element can make it possible to increase the mechanical strength of the alloy by solid solution and/or by dispersoids which may form during the manufacture of the part or during post-manufacturing heat treatments. This element has low solubility in aluminum. Adding this element can harden the alloy without having a significant impact on conductivity. Cu and/or Ag:

According to the present invention, the Cu and/or Ag elements may be present in the aluminum alloy in a mass fraction of 0.10 to 3.00%, preferably 0.10 to 2.00%, preferably from 0.10 to 1.60%, preferably from 0.10 to 1.00%, preferably from 0.10 to 0.70% each and in total.

These elements can make it possible to increase the mechanical strength of the alloy by solid solution and/or by hardening precipitates which may form during the manufacture of the part or during post-manufacturing heat treatments.

SH

According to the present invention, the element Si can be present in the aluminum alloy in a mass fraction of less than 3.00%, preferably less than 2.00%, preferably less than 1.00%, preferably less than 0.50%; in one embodiment, the Si content is less than 0.30%, preferably less than 0.20%. Preferably, the mass fraction of Si is greater than 500 ppm, preferably greater than 0.10%, preferably greater than 0.15%.

The addition of Si in the presence of Zr can lead to the formation of coarse AlZrSi phases which would limit the hardening power of Zr after heat treatment.

Sc:

According to the present invention, the element Sc can be present in the aluminum alloy in a mass fraction less than 0.80%, preferably less than 0.70%, preferably less than 0.60%, preferably less than 0 .50%, preferably less than 0.40%, preferably less than 0.30%. Preferably, the mass fraction of Sc is greater than 500 ppm, preferably greater than 0.10%, preferably greater than 0.15%, preferably greater than 0.20%.

This element can present the same technical effects as the elements Zr, Hf and Er. On the other hand, according to a variant of the present invention, the inventors have found that a good compromise between the mechanical properties and the conductivity can also be obtained, preferably after heat treatment, by at least partially replacing the group of elements Co, La, Ce, mischmetal, W, Ta, Mo and/or Nb per Sc, according to the mass fractions as described above.

Mg, Zn and/or Li:

According to the present invention, the elements Mg, Zn and/or Li may be present in the aluminum alloy in a mass fraction of less than 2.00%, preferably less than 1.00%, preferably less than 0.50%, more preferably less than 0.30% each. Preferably, the mass fraction of Mg, Zn and/or Li is greater than 500 ppm, preferably greater than 0.10%, preferably greater than 0.15% each.

These elements can increase the mechanical strength of the alloy by solid solution. However, these elements are sensitive to evaporation during laser melting, which can lead to the formation of smoke and instability of the melt pools. Excessive addition of these elements can significantly lower electrical conductivity. Thus, according to one embodiment, the addition of these elements is therefore preferably to be avoided.

Nd, Y, Tm, Lu, Yb, Sr, Ba, Sb, Bi, Ca, P, B, In and/or Sn:

According to the present invention, at least one element chosen from: Nd, Y, Tm, Lu, Yb, Sr, Ba, Sb, Bi, Ca, P, B, In and Sn may be present in the aluminum alloy according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.50%, preferably less than or equal to 0.30%, more preferably less than or equal to 0.10%, even more preferably less than or equal at 700 ppm each, and less than or equal to 2.00%, preferably less than or equal to 1.00%, preferably less than or equal to 0.50%, preferably less than or equal to 0.30% in total. Preferably, the mass fraction of Nd, Y, Tm, Lu, Yb, Sr, Ba, Sb, Bi, Ca, P, B, In and Sn is greater than 100 ppm, preferably greater than 300 ppm, preferably greater at 500 ppm each and in total.

These elements can make it possible to increase the mechanical strength of the alloy by solid solution and/or by dispersoids which can form during the manufacture of the part or during post-manufacturing heat treatments. However, the excessive addition of these elements can degrade the conductivity of the alloy, which is why, according to one embodiment, their addition is preferably in a mass fraction of less than 700 ppm each.

It should be noted that, preferably, the alloys according to the present invention are not AA6xxx type alloys, due to the absence of simultaneous addition of Si and Mg in quantities greater than 0.2%.

The process may include, following the formation of the layers, that is to say following the formation of the final part, an application of at least one heat treatment. This treatment is also called post-manufacturing heat treatment or post-processing. Post-manufacturing heat treatment may be or include tempering or annealing. It can also include solution and quenching, even if we prefer to avoid them. It may also feature hot isostatic compression. According to a first variant, in order to favor the mechanical properties, the post-manufacturing heat treatment can be carried out: at a temperature T' greater than 400°C, in which case the duration of the post-manufacturing heat treatment is between 0.1 h and 50 hours, preferably from 0.1 hours to 10 hours; or at a temperature T' between 300°C and 400°C, in which case the duration of the post-manufacturing heat treatment is between 0.1 h and 200 h.

According to a second variant, in order to favor the thermal or electrical conduction properties, the post-manufacturing heat treatment can be carried out at a temperature T' greater than or equal to 350°C or 400°C for a duration of 0.1 h at 200 h, so as to obtain optimal thermal or electrical conductivity.

According to another variant, two-stage post-manufacturing heat treatments can make it possible to maximize electrical conductivity. These treatments consist of first making a first level at a temperature T'1 greater than 450°C for a duration of 0.1 h to 100 h, followed by a second level at a temperature T'2 of 300°C. C to 450°C for a duration of 0.1 h to 200 h.

According to another variant, two-stage post-manufacturing heat treatments can make it possible to maximize the electrical conductivity and/or hardness. These treatments consist of first making a first level at a temperature T'1 lower than 380°C for a duration of 0.1 h to 200 h, followed by a second level at a temperature T'2 of 380°C. C to 450°C for a duration of 0.1 h to 200 h.

According to another variant, three-stage post-manufacturing heat treatments can make it possible to maximize the electrical conductivity and/or hardness. These treatments consist of first making a first level at a temperature T'1 of 250°C to 450°C for a duration of 0.1 h to 200 h, followed by a second level at a temperature T'2 greater than 450°C for a duration of 0.1 h to 100 h, followed by a third level at a temperature T'3 of 250°C to 450°C for a duration of 0.1 h to 200 h.

Multi-level treatments with a number of levels greater than 3 can also be considered.

According to one embodiment, the method may include hot isostatic compression (CIC). The CIC treatment can in particular make it possible to improve the elongation properties and the fatigue properties. Hot isostatic pressing can be performed before, after or instead of post-manufacturing heat treatment. Advantageously, the hot isostatic compression is carried out at a temperature of 250°C to 500°C and preferably from 300°C to 450°C, at a pressure of 500 to 3000 bars and for a duration of 0.5 to 100 hours. According to an advantageous embodiment, the process does not include quenching following the formation of the layers, that is to say following the formation of the final part, or following the post-manufacturing heat treatment. Thus, preferably, the process does not include solution steps followed by quenching.

The use of post-manufacturing heat treatment, the manufacturing being carried out by an additive manufacturing process, can make it possible to create relaxation conditions making it possible to eliminate residual stresses as well as a precipitation of hardening phases. We also speak of thermal expansion. The inventors observed that it was preferable for the set temperature T' of the post-manufacturing heat treatment to be between 300°C and 500°C.

The possible heat treatment and/or hot isostatic compression makes it possible in particular to increase the hardness or the elastic limit and the electrical conductivity of the product obtained. However, it should be noted that, generally, the higher the temperature, the more conductivity (electrical or thermal) is favored to the detriment of mechanical resistance.

According to one embodiment, in addition to the temperature T' of the post-manufacturing heat treatment, the rise in temperature, initiating the post-manufacturing heat treatment, is preferably as rapid as possible. For example, during the temperature rise, the temperature rise speed AT' (usually designated by those skilled in the art by "heating rate" in °C per minute or in °C per second) is preferably greater than 5°C per minute or greater than 10°C per minute, or preferably greater than 20°C per minute and more advantageously greater than 40°C per minute, and more advantageously greater than 100°C per minute. By temperature rise, we mean the rise in temperature to which the part is subjected during post-manufacturing heat treatment. It seems optimal that the rise in temperature is instantaneous, that is to say that the manufactured part is subjected, from the start of the post-manufacturing heat treatment, to the set temperature T' of the post-manufacturing heat treatment. An instantaneous rise in temperature can be obtained by placing the manufactured part in a hot oven, already brought to the set temperature T', or by a rapid heating means such as a fluidized bed or molten salt bath. The temperature rise can also be ensured by induction heating.

For the same temperature rise outside the room, the temperature variation inside the room depends in particular on the heating medium (liquid or air or inert gas) as well as the shape of the room. In particular, the temperature in the thickness or on the surface of the part may be different. This is the reason why the rise in temperature previously mentioned corresponds to the temperature outside the room. The combination of a preheating temperature T, a post-fabrication heat treatment temperature T' and a temperature rise speed AT', during the rise in temperature of the post-fabrication heat treatment, in the pre-value ranges cited, makes it possible to obtain parts with good resistance to thermal cracking.

According to another embodiment, suitable for structurally hardening alloys, a solution can be carried out followed by quenching and tempering of the formed part and/or hot isostatic compression. Hot isostatic compression can in this case advantageously replace dissolution.

However, the process according to the invention is advantageous, because it preferably does not require solution treatment followed by quenching. Solution processing can have a detrimental effect on mechanical strength in certain cases by contributing to a coarsening of dispersoids or fine intermetallic phases. Preferably, the process according to the present invention does not include solution and/or quenching following the formation of the layers, that is to say following the formation of the final part, or following the post-heat treatment. manufacturing.

Preferably, the method according to the present invention is such that the part 20 presents:

In the as-manufactured state, an electrical conductivity greater than 6 MS/m, preferably greater than 7 MS/m, preferably greater than 8 MS/m; And

In the as-manufactured state, a Knoop HK0.05 hardness less than 140, preferably less than 130, preferably less than 120; And

After post-treatment for 4 hours at 400°C, a Knoop HK0.05 hardness greater than 70, preferably greater than 80, preferably greater than 90, preferably greater than 100, preferably greater than 114.

According to one embodiment, the method according to the present invention further optionally comprises a machining treatment, and/or a chemical, electrochemical or mechanical surface treatment, and/or a tribofinishing. These treatments can be carried out in particular to reduce roughness and/or improve corrosion resistance and/or improve resistance to fatigue crack initiation.

Optionally, it is possible to carry out mechanical deformation of the part, for example after additive manufacturing and/or before heat treatment.

Although described in connection with an additive manufacturing method of the LPBF type, the process can be applied to other additive manufacturing methods of the WAAM (Wire plus Arc Additive Manufacturing) type, mentioned in connection with the prior art. Figure 2 represents such an alternative. An energy source 31, in this case a torch, forms an electric arc 32. In this device, the torch 31 is held by a welding robot 33. The part 20 to be manufactured is arranged on a support 10. In this example, the manufactured part is a wall extending along a transverse axis Z perpendicular to a plane XY defined by the support 10. Under the effect of the electric arc 12, a wire of contribution 35 melts to form a weld bead. The welding robot is controlled by a digital model M. It is moved so as to form different layers 20i...20 _n , stacked on top of each other, forming the wall 20, each layer corresponding to a weld bead. Each layer 20i...20 _n extends in the XY plane, according to a pattern defined by the digital model M.

The diameter of the filler wire is preferably less than 3 mm. It can be from 0.5 mm to 3 mm and is preferably from 0.5 mm to 2 mm, or even from 1 mm to 2 mm. It is for example 1.2 mm.

Other processes are also possible, for example, and in a non-limiting manner:

- selective laser sintering;

- direct metal laser sintering (Direct Metal Laser Sintering);

- selective sintering by heating (Selective Heat Sintering);

- electron beam melting (Electron Beam Melting);

- deposition by laser fusion (Laser Melting Deposition);

- direct deposit by energy input (Direct Energy Deposition);

- direct metal deposition (Direct Metal Deposition);

- direct laser deposition (Direct Laser Deposition);

- Laser Deposition Technology;

- laser engineering of net shapes (Laser Engineering Net Shaping);

- laser cladding technology (Laser Cladding Technology);

- laser freeform manufacturing technology (Laser Freeform Manufacturing Technology);

- deposition by laser fusion (Laser Metal Deposition);

- cold spray (Cold Spray Consolidation);

- additive manufacturing by friction (Additive Friction Stir);

- plasma spark sintering or flash sintering (Field Assisted Sintering Technology or spark plasma sintering); Or

- rotary friction welding (Inertia Rotary Friction Welding).

The solutions according to the present invention are particularly suitable for the cold spray process, in particular because of the low hardness of the powder, which facilitates deposition. The part can then be hardened by hardening annealing (heat post-treatment). The solutions according to the present invention are particularly suitable for applications in the electrical, electronic and heat exchanger fields.

The invention will be explained in more detail in the examples below, which are given by way of illustration and not limitation.

EXPERIMENTAL EXAMPLES

Example 1

The tested alloys were cast in a copper mold using an Induthem VC 650V machine to obtain ingots measuring 130 mm in height, 95 mm in width and 5 mm in thickness.

The alloys as described in Table 1 below were tested by a rapid prototyping method. Samples were machined for scanning the surface with a laser, in the form of wafers measuring 60 x 22 x 3 mm, from the ingots obtained above. The wafers were placed in an LPBF machine and scans of the surface were performed with a laser following the same scanning strategy and process conditions representative of those used for the LPBF process. It was indeed found that it was possible in this way to evaluate the suitability of alloys for the LPBF process and in particular, the sensitivity to hot cracking, the hardness in the raw state and after heat treatment, the conductivity electrical in its raw state and after heat treatment.

Under the laser beam, the metal melts in a bath approximately 500 pm thick. After passing the laser, the metal cools quickly as in the LPBF process. After laser scanning, a thin surface layer approximately 500 μm thick was melted and then solidified. The properties of the metal in this layer are close to the properties of the metal at the core of a part manufactured by LPBF, because the scanning parameters have been carefully chosen. Laser scanning of the surface of the different samples was carried out using an AddUp brand FormUP® 350 selective laser powder bed fusion (LPBF) machine. The laser source had a power of 400 W, the vector spacing was 60 pm, the scanning speed was 500 mm/s and the beam diameter was 65 pm.

On each wafer, two rectangular surfaces of 5 mm x 35 mm each were remelted for hardness measurements and one rectangular surface of 15 mm x 18 mm was remelted for electrical conductivity measurement.

Figure 3 shows an example of a wafer after laser reflow. Reference 1 corresponds to the two rectangular surfaces remelted and used for hardness measurement, reference 2 corresponds to the rectangular surface remelted and used for measuring electrical conductivity and reference 3 corresponds to the non-remelted surface of the initial wafer.

Following each test, a thermal post-treatment was applied to certain samples. The heat treatment was annealing, at a temperature of 400°C, for 1 hour, or 4 hours, or 7 hours.

Knoop hardness measurement

Hardness is an important property for alloys. Indeed, if the hardness in the layer recast by scanning the surface with a laser is high, a part made with the same alloy will have a high elastic limit.

To evaluate the hardness of the recast layer, the wafers obtained above were cut in the plane perpendicular to the direction of the laser passes and were then polished. After polishing, hardness measurements were carried out in the recast layer. The hardness measurement was carried out with a Durascan model device from Struers. The Knoop 50 g hardness method with the long diagonal of the indentation placed parallel to the plane of the recast layer was chosen to keep sufficient distance between the indentation and the edge of the sample. 30 indentations were positioned at mid-thickness of the recast layer. Figure 4 shows an example of the hardness measurement. Reference 4 corresponds to the remelted layer, reference 5 corresponds to a Knoop hardness imprint and reference 6 corresponds to the non-remelted zone.

The hardness was measured according to the Knoop scale with a load of 50 g after laser treatment (in the raw state) and after additional heat treatment at 400°C for variable durations, making it possible in particular to assess the ability to the alloy hardening during heat treatment and the effect of a possible CIC treatment on the mechanical properties and electrical conductivity.

Electrical conductivity measurement

The 15 mm x 18 mm recast rectangular surface of each wafer was subjected to electrical conductivity measurements, based on the fact that electrical conductivity evolves similarly to thermal conductivity. A linear dependence relationship between thermal conductivity and electrical conductivity, according to Wiedemann Franz's law, was validated in the Hatch publication "Aluminium properties and physical metallurgy" ASM Metals Park, OH, 1988. Electrical conductivity measurements have was carried out at the center of the recast surface in the plane of the large face of the wafers (plane parallel to the direction of the laser passes). The conductivity measurements were carried out in the raw state (without treatment thermal post-manufacturing) and after heat treatment at 400°C for varying periods of 1 hour, 4 hours or 7 hours. An average of 5 different measurements was taken for each condition.

The conductivity measurements were carried out at a temperature of approximately 20°C using a Foerster Sigmatest 2.069 type measuring device at a frequency of 960 kHz. The choice of this frequency makes it possible to restrict the depth of measurement of the electrical conductivity at the level of the remelted zone of the wafer.

The composition of the aluminum alloys tested is presented in Table 1 below, in percentages by weight. We used a reference alloy: composition No. 1, which contains aluminum, as well as the following alloying elements: Fe (1.00%) and Zr (1.20%).

[Table 1]

Table 2 below shows the Knoop hardness (HK0.05) and electrical conductivity values measured for each alloy, after laser remelting, in the raw state (0 hours of heat treatment).

[Table 2]

Table 3 below shows the Knoop hardness (HK0.05) and electrical conductivity values measured for each alloy, after laser remelting, and after annealing at 400°C, carried out after laser remelting, for 1 hour. [Table 3]

Table 4 below shows the Knoop hardness (HK0.05) and electrical conductivity values measured for each alloy, after laser remelting, and after annealing at 400°C, carried out after laser remelting, for 4 hours.

[Table 4]

Table 5 below shows the Knoop hardness (HK0.05) and electrical conductivity values measured for each alloy, after laser remelting, and after annealing at 400°C, carried out after laser remelting, for 7 hours.

[Table 5]

The results in Tables 2, 3, 4 and 5 show that, for all the solutions tested, the conductivity and hardness values were the lowest in the raw state. The additional heat treatment carried out at 400°C made it possible to increase both the electrical conductivity and the Knoop hardness (HK0.05) compared to the raw state.

For all of the solutions tested, maximum conductivity was obtained after 7 hours at 400°C.

For all of the solutions tested, maximum hardness was obtained after treatment at 400°C between 1 hour and 7 hours. The duration allowing hardness to be maximized seemed to be between 0.5 hours and 10 hours for all of the solutions tested.

An increase in the duration of the heat treatment at 400°C for periods greater than 10 hours would further increase the thermal conductivity but would lower the hardness.

The choice of final heat treatment can thus be chosen according to the intended application. For alloys containing Sc, a heat treatment temperature ranging from 300 to 400°C for a duration of 0.5 hours to 10 hours could be optimal to maximize hardness. For example a temperature of 325°C and a duration of 4 hours.

Reference alloy No. 1 made it possible to obtain the highest electrical conductivity for all the conditions tested: in the raw state (without post-manufacturing heat treatment) and after heat treatment at 400°C for variable durations of 1 hour, 4 hours or 7 hours. The best Knoop hardness (HK0.05)/electrical conductivity (MS/m) compromise for this alloy was obtained for a post-manufacturing heat treatment of 4 hours at 400°C with respective values of 113.32 HK0.05 for hardness and 28.64 MS/m for conductivity. This alloy offers an excellent candidate for applications requiring high thermal or electrical conductivity such as heat exchangers, heat sinks, electronic enclosures, RF antennas, etc... However the maximum hardness offered by this alloy (113.32 HK0.05) remains insufficient for certain applications not requiring particular performance in terms of electrical conductivity, but which require high mechanical resistance, such as structural parts, hydraulic blocks, etc.

Tables 4 and 5 show that all of the alloys of the invention make it possible to offer, after heat treatment, a Knoop hardness (HK0.05) greater than that of the reference alloy No. 1 with a maximum hardness of 149.69 HK0.05 obtained for alloy No. 4 after post-manufacturing heat treatment for 4 hours at 400°C.

All of the alloys of the invention can make it possible to obtain both very good processability of parts in the LPBF process and excellent mechanical performance of parts in service. Good processability of parts in the LPBF process can be obtained by combining in the as-manufactured state, a sufficiently low level of hardness (Knoop HK0.05 hardness in the as-manufactured state less than 140, preferably less than 130, preferably less than 120) and a sufficiently high thermal or electrical conductivity (electrical conductivity in the as-manufactured state greater than 6 MS/m, preferably greater than 7 MS/m, preferably greater than 8 MS/m). This combination of hardness and conductivity can limit the level of residual stresses of the parts in the raw manufacturing state, which can significantly limit the risk of cracking, delamination or distortion, thus significantly improving the processability of the parts in LPBF process. Excellent mechanical performance of parts in service can be obtained by maximizing the hardness of parts after post-manufacturing heat treatment (Knoop HK0.05 hardness greater than 70, preferably greater than 80, preferably greater than 90, preferably greater than 100 , preferably greater than 114 for example after 4 hours of heat treatment at 400°C).

Table 1 shows that, unlike reference alloy No. 1, all of the alloys of the invention had a total content of addition elements greater than 3%.

Claims

CLAIMS Process for manufacturing a part (20) comprising a formation of successive metal layers (20i...20 _n ), superimposed on each other, each layer being formed by the deposition of a filler metal (15, 25), the filler metal being subjected to an energy supply so as to melt and constitute, by solidifying, said layer, the process being characterized in that the filler metal (15, 25) is an aluminum alloy comprising the following alloy elements (% by weight):

- at least one alloy element chosen from Cr, V, Ti and Mn, in a mass fraction greater than 0.50%, preferably more than 0.50 to 6.00%, preferably 1.00 to 5 .00%, more preferably from 1.00 to 4.00%, even more preferably from 1.00 to 3.00%, each for V, Ti and Mn, and in total; and at a mass fraction of more than 0.50 to 3.00% for Cr;

- optionally at least one alloy element chosen from: Cu and Ag, according to a mass fraction of 0.10 to 3.00%, preferably 0.10 to 2.00%, preferably 0.10 to 1.60%, preferably 0.10 to 1.00%, preferably 0.10 to 0.70% each and in total;

- optionally Si, in a mass fraction less than 3.00%, preferably less than 2.00%, preferably less than 1.00%, preferably less than 0.50%; preferably less than 0.30%, preferably less than 0.20%;

- optionally at least one element chosen from: Nd, Y, Tm, Lu, Yb, Sr, Ba, Sb, Bi, Ca,

P, B, In and Sn, according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.50%, preferably less than or equal to 0.30%, more preferably less than or equal to 0, 10%, even more preferably less than or equal to 700 ppm each, and less than or equal to 2.00%, preferably less than or equal to 1.00%, preferably less than or equal to 0.50%, preferably less than or equal to 0.30% in total;

- impurities: < 0.05% individually, and in total <0.15%; remains aluminum. Method according to claim 1, characterized in that the aluminum alloy comprises at least one alloy element chosen from: Co, La, Ce, mischmetal, W, Ta, Mo and Nb. Process according to any one of the preceding claims, in which the mass fraction of aluminum is less than 97%. Tl

4. Method according to any one of the preceding claims, in which the part (20) has:

- In the as-manufactured state, an electrical conductivity greater than 6 MS/m, preferably greater than 7 MS/m, preferably greater than 8 MS/m; And

- In the raw manufacturing state, a Knoop HK0.05 hardness less than 140, preferably less than 130, preferably less than 120; And

- After post-treatment for 4 hours at 400°C, a Knoop HK0.05 hardness greater than 70, preferably greater than 80, preferably greater than 90, preferably greater than 100, preferably greater than 114.

5. Method according to any one of the preceding claims, comprising, following the formation of the layers (20i...20 _n ), that is to say following the formation of the final part, an application of a post-manufacturing heat treatment, preferably tempering or annealing.

6. Method according to any one of the preceding claims, not comprising solution and/or quenching following the formation of the layers, that is to say following the formation of the final part, or following the treatment post-manufacturing thermal.

7. Method according to any one of the preceding claims, characterized in that it is carried out at a preheating temperature T of up to 500°C.

8. Method according to any one of the preceding claims, in which the filler metal takes the form of a powder (15), the exposure of which to a beam of light (12) or charged particles results in fusion localized followed by solidification, so as to form a solid layer (20i...20 _n ).

9. Method according to any one of claims 1 to 7, in which the filler metal comes from a filler wire (25), the exposure of which to a heat source (22) results in melting localized followed by solidification, so as to form a solid layer (20i...20 _n ).

10. Metal part obtained by a process which is the subject of any one of the preceding claims. Powder, intended to be used as a feed material for an additive manufacturing process, characterized in that it consists of an aluminum alloy, comprising the following alloy elements (% by weight):

- optionally Si, in a mass fraction less than 3.00%, preferably less than 2.00%, preferably less than 1.00%, preferably less than 0.50%; preferably less than 0.30%, preferably less than 0.20%; - optionally Sc, according to a mass fraction less than 0.80%, preferably less than 0.70%, preferably less than 0.60%, preferably less than 0.50%, preferably less than 0.40%, preferably less than 0.30%;

- impurities: < 0.05% individually, and in total < 0.15%; remains aluminum. Use of a powder according to claim 11, in a manufacturing process chosen from: electron beam melting, cold spraying, laser fusion deposition, additive manufacturing by friction, sintering by plasma spark or rotary friction welding, preferably cold spray.