Manufacturing method for aluminum alloy parts

Abstract

The present invention provides a method for manufacturing a continuous solid metal layer (201...20 n The present invention relates to a method for manufacturing a part, comprising the formation of a filler metal (25), each layer being formed by the deposition of a metal called filler metal (25), characterized in that the part has a specific grain structure. The invention also relates to parts obtained by this method and alternative methods. The alloys used in the additive manufacturing method according to the invention make it possible to obtain parts with outstanding properties.

Description

[Technical Field]

[0001] The technical field of the present invention is a method for manufacturing aluminum alloy parts, utilizing additive manufacturing technology. [Background technology]

[0002] Since the 1980s, additive manufacturing technologies have developed significantly. These technologies involve forming parts by adding material, which is the opposite of processing technologies that aim to cut materials. While additive manufacturing was previously limited to prototyping, it is now being used for mass production of industrial products, including metal parts.

[0003] The term "additive manufacturing" is defined in the French standard XP E67-001 as "a set of methods that enable the production of physical objects layer by layer from digital objects by the addition of material." Standard ASTM F2792 (January 2012) also defines additive manufacturing. Various additive manufacturing methods are also defined and described in the standard ISO / ASTM 17296-1. International Publication 2015 / 006447 describes the use of additive manufacturing to produce low-porosity aluminum parts. The application of successive layers is generally achieved by applying a material called a filler, followed by the melting or sintering of the filler using a laser beam, electron beam, plasma torch, or arc-type energy source. Regardless of the additive manufacturing method applied, the thickness of each added layer is approximately tens or hundreds of microns.

[0004] One method of additive manufacturing is the melting or sintering of filler materials in powder form. This can be done by melting or sintering with an energy beam.

[0005] In particular, selective sintering techniques using lasers (selective laser sintering, SLS, or direct metal laser sintering, DMLS) are known, in which a powder layer of metal or metal alloy is applied to a part to be manufactured and selectively sintered according to a digital model using thermal energy derived from a laser beam. Another type of metal forming method includes selective laser melting (selective laser melting, SLM) or electron beam melting (electron beam melting, EBM), in which thermal energy supplied by an induced laser or electron beam is used to selectively melt the metal powder (instead of sintering), so that the metal powder fuses together as it cools and solidifies.

[0006] Laser deposition (LMD) is also known, where the powder is melted by a laser beam at the same time it is introduced.

[0007] International Publication No. 2016 / 209652 describes a method for producing aluminum with high mechanical strength, including the preparation of finely ground aluminum powder having one or more powder sizes and approximate forms as approximately desired; sintering of the powder to form a product by additive manufacturing; solution treatment; quenching; and tempering of the additively manufactured aluminum.

[0008] There is a growing demand for aluminum alloys that can withstand high temperatures and possess high strength for use in SLM applications. 4xxx alloys (primarily Al10SiMg, Al7SiMg, and Al12Si) are the most mature aluminum alloys for SLM applications. While these alloys offer excellent suitability for SLM methods, they suffer from limited mechanical properties.

[0009] Scalmalloy® (German Patent Application Publication No. 102007018123), developed by APWorks, provides excellent mechanical properties at ambient temperatures (using a post-manufacturing heat treatment at 325°C for 4 hours). However, this solution suffers from high costs in powder form due to its high scandium content (approximately 0.7% Sc) and the need for a special atomization process. This solution also has the problem of poor mechanical properties at high temperatures, such as above 150°C.

[0010] Addalloy® (International Publication No. 2018 / 00935), developed by NanoAl, is an AlMgZr alloy. This alloy has the problem of having limited mechanical properties at high temperatures.

[0011] Alloy 8009 (Al Fe V Si), developed by Honeywell (U.S. Patent Application Publication No. 2013 / 13801662), offers excellent mechanical properties in its raw state at both ambient temperatures and high temperatures up to 350°C. However, Alloy 8009 suffers from machinability issues (risk of cracking), possibly related to its high hardness in its raw state.

[0012] Several studies have been conducted regarding the effect of assembly tray temperature on crack susceptibility. In particular, U.S. Patent Application Publication 2019 / 0039183 recommends temperatures of 350-500°C for several aluminum alloys of the 2xxx, 5xxx, 6xxx, or 7xxx types. Another example is the publication "Investigation on reducing distortion by preheating during manufacture of aluminum components using selective laser melting" (Buchbinder et al., Journal of Laser Applications, 26, 2014), which recommends temperatures of 150-250°C for AlSi10Mg type aluminum alloys.

[0013] The mechanical properties of aluminum parts obtained by additive manufacturing depend on the alloy forming the filler material, and more precisely its composition, the parameters of the additive manufacturing method, as well as the heat treatment applied. The inventors have determined specific features that make it possible to obtain parts with outstanding properties when used in an additive manufacturing method. Specifically, the parts obtained according to the present invention have improved properties compared to the prior art, particularly from the perspective of the elastic limit at 200 °C and the crack sensitivity during the SLM process.

Prior Art Documents

Patent Documents

[0014]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Non-Patent Documents

[0015]

Non-Patent Document 1

Summary of the Invention

[0016] The inventors have achieved better control of the granular structure through appropriate selection of the composition and process parameters, specifically by controlling the manufacturing temperature (e.g., the temperature of the manufacturing tray), enabling: - Eliminating the problem of crack sensitivity; - Maintaining excellent curing ability (the difference in mechanical strength at ambient temperature between the as-manufactured state and the state after heat treatment at approximately 400 °C); and, - Providing excellent mechanical performance at ambient and high temperatures; which has been found to be possible.

[0017] A first object of the present invention is a method for manufacturing a component including the formation of successive solid metal layers superposed on one another, wherein each layer depicts a pattern defined from a digital model and each layer is formed by the deposition of a metal called a filler material, the filler material being adapted to constitute said layer by melting and solidifying upon receiving an energy supply, the filler material being in the form of a powder, and melting and subsequent solidification being brought about as a result of exposing this powder to an energy beam to form a solid layer,<s characterized in that the component is manufactured at a temperature of 25 to 150 °C; and also in that the component has a grain structure such that the area fraction of equiaxed grains having a surface area of less than 2.16 μm 2 is less than 44%, preferably less than 40%, suitably less than 36%; and the area fraction of columnar grains is 22% or more, preferably 25% or more, suitably 30% or more; and also in that the filler material (25) is: - Zr in a total amount of 0.30% or more, preferably 0.30 to 2.50%, suitably 0.40 to 2.00%, more suitably 0.40 to 1.80%, even more suitably 0.50 to 1.60%, even more suitably 0.60 to 1.50%, even more suitably 0.70 to 1.40%, even more suitably 0.80 to 1.20% by mass fraction; - Sc less than 0.30%, preferably less than 0.20%, more preferably less than 0.10%, and more preferably less than 0.05% according to the mass fraction; - Mg in mass fraction of less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Zn in mass fraction less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Optionally, at least one element selected from Ni, Mn, Cr, and / or Cu, in mass fractions of 0.50 to 7.00%, preferably 1.00 to 6.00%, each; preferably, in mass fractions of less than 25.00%, more preferably less than 20.00%, and more preferably less than 15.00% in total; - Optionally, at least one element selected from Hf, Ti, Er, W, Nb, Ta, Y, Yb, Nd, Ce, Co, Mo, Lu, Tm, V and / or mischmetal, in a mass fraction of 5.00% or less for each element, preferably 3% or less, and a total of 15.00% or less, preferably 12% or less, and more preferably 5% or less; - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 1.00% or less, preferably 0.5% or less, more preferably 0.3% or less, more preferably 0.1% or less, even more preferably 700 ppm or less, and in a total of 2.00% or less, preferably 1% or less; - Optionally, according to the first modified form, the Fe content is 0.50 to 7.00%, preferably 1.00 to 6.00%, according to the mass fraction, or according to the second modified form, the Fe content is 1.00% or less, preferably 0.5% or less, preferably 0.3% or less, more preferably 0.1% or less, and even more preferably 700 ppm or less, according to the mass fraction; - Optionally, at least one element selected from Ag in mass fractions of 0.06 to 1.00% and / or Li in mass fractions of 0.06 to 1.00%; - Optionally, impurities less than 0.05% (i.e., 500 ppm) each by mass fraction, and less than 0.15% in total; - The remainder is aluminum; This method is characterized by using an aluminum alloy that contains at least the alloying element.

[0018] Those skilled in the art will know that other elements also have effects equivalent to those of Zr. In particular, Ti, V, Sc, Hf, Er, Tm, Yb, or Lu can be mentioned. Therefore, according to one variant of the first subject of the present invention, Zr can be partially substituted by at least one element selected from Ti, V, Sc, Hf, Er, Tm, Yb, and Lu, preferably up to 90% of the mass fraction of Zr.

[0019] Therefore, the second object of the present invention is a continuous solid metal layer (201...20) superimposed on each other. n In a method for manufacturing a part including the formation of a solid layer (201...20), each layer is formed by the deposition of a metal (25) called a filler material, the filler material melts and solidifies upon energy supply to form the layer, the filler material is in the form of a powder (25), and as a result of exposing this powder to an energy beam (32), melting and subsequent solidification are brought about to form a solid layer (201...20 n A method that will result in the formation of The components are characterized by being manufactured at temperatures between 25 and 150°C; Furthermore, each component is 2.16 μm 2 A grain structure characterized by having a surface area fraction of equiaxed grains having less than 44%, preferably less than 40%, and more preferably less than 36%; and a grain structure in which the surface area fraction of columnar grains is 22% or more, preferably 25% or more, and more preferably 30% or more; Also, the filler material (25) is: - Knowing that Zr accounts for 10% to less than 100% of the following percentage range, at least one element selected from Ti, V, Sc, Hf, Er, Tm, Yb, and Lu and Zr, in total, according to mass fraction, of 0.30% or more, preferably 0.30-2.5%, more preferably 0.40-2.0%, more preferably 0.40-1.80%, even more preferably 0.50-1.60%, even more preferably 0.60-1.50%, even more preferably 0.70-1.40%, and even more preferably 0.80-1.20%; - Mg in mass fraction of less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Zn in mass fraction less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Optionally, at least one element selected from Ni, Mn, Cr, and / or Cu, in mass fractions of 0.50 to 7.00%, preferably 1.00 to 6.00%, each; preferably, in mass fractions of less than 25.00%, more preferably less than 20.00%, and more preferably less than 15.00% in total; - Optionally, at least one element selected from W, Nb, Ta, Y, Nd, Ce, Co, Mo and / or mischmetal, in a mass fraction of 5.00% or less for each element, preferably 3% or less, and a total of 15.00% or less, preferably 12% or less, and more preferably 5% or less; - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 1.00% or less, preferably 0.5% or less, more preferably 0.3% or less, more preferably 0.1% or less, even more preferably 700 ppm or less, and in a total of 2.00% or less, preferably 1% or less; - Optionally, according to the first modified form, the Fe content is 0.50 to 7.00%, preferably 1.00 to 6.00%, according to the mass fraction, or according to the second modified form, the Fe content is 1.00% or less, preferably 0.5% or less, preferably 0.3% or less, more preferably 0.1% or less, and even more preferably 700 ppm or less, according to the mass fraction; - Optionally, at least one element selected from Ag in mass fractions of 0.06 to 1.00% and / or Li in mass fractions of 0.06 to 1.00%; - Optionally, impurities less than 0.05% (i.e., 500 ppm) each by mass fraction, and less than 0.15% in total; - The remainder is aluminum; This method is characterized by using an aluminum alloy that contains at least the alloying element.

[0020] Preferably, the alloy according to the present invention, and in particular the alloys relating to the first and second subjects of the present invention, contain at least 80%, more preferably at least 85%, of aluminum by mass.

[0021] The melting of the powder may be partial or complete. Preferably, 50-100%, more preferably 80-100%, of the exposed powder melts.

[0022] Each layer, in particular, can depict patterns defined from digital models.

[0023] Without being constrained by theory, the alloy according to the present invention appears to be extremely advantageous in offering an excellent compromise between crack susceptibility and mechanical strength, particularly tensile strength at cold temperatures and high temperatures such as 200°C.

[0024] As demonstrated in the following examples, the grain structure and the manufacturing temperature of the component appear to be major influencing factors for the crack susceptibility of aluminum alloys.

[0025] Preferably, and in particular according to the first and second aspects of the present invention, the components are manufactured at a temperature of 50 to 130°C, more preferably 50 to 110°C, even more preferably 80 to 110°C, and even more preferably 80 to 105°C.

[0026] Preferably, in particular, according to the first and second subjects of the present invention, the aluminum alloy is: - Zr in a mass fraction of 0.50-3.00%, preferably 0.50-2.50%, more preferably 0.60-1.40%, more preferably 0.70-1.30%, even more preferably 0.80-1.20%, even more preferably 0.85-1.15%, and even more preferably 0.90-1.10%; - Mn in a mass fraction of 1.00 to 7.00%, preferably 1.00 to 6.00%, more preferably 2.00 to 5.00%; more preferably 3.00 to 5.00%, and even more preferably 3.50 to 4.50%; - Ni in a mass fraction of 1.00 to 6.00%, preferably 1.00 to 5.00%, more preferably 2.00 to 4.00%, and more preferably 2.50 to 3.50%; - Optionally, according to mass fraction, 1.00% or less, preferably 0.50% or less, preferably 0.30% or less; and preferably 0.05% or more, preferably 0.10% or more of Fe; - Optionally, Si in an amount of 1.00% or less, preferably 0.50% or less, according to the mass fraction; - Optionally, 1.00 to 5.00%, preferably 1.00 to 3.00%, and more preferably 1.50 to 2.50% of Cu, according to mass fraction; Includes.

[0027] The elements Hf, Ti, Er, W, Nb, Ta, Y, Yb, Nd, Ce, Co, Mo, Lu, Tm, V, and / or mischmetals can lead to the formation of dispersed phases or fine intermetallic phases that can increase the hardness of the resulting material. As is known to those skilled in the art, the composition of mischmetals is generally about 45-50% cerium, 25% lanthanum, 15-20% neodymium, and 5% praseodymium.

[0028] According to one embodiment, the addition of La, Bi, Mg, Er, Yb, Y, Sc and / or Zn is avoided, and the preferred mass fraction of each of these elements is less than 0.05%, preferably less than 0.01%.

[0029] According to another embodiment, the addition of Fe and / or Si is avoided. However, it is known to those skilled in the art that these two elements are generally present in common aluminum alloys in the amounts defined above. Thus, the above-mentioned amounts may also correspond to the impurity amounts of Fe and Si.

[0030] The elements Ag and Li can affect the strength of a material either through hardening precipitation or through their effects on solid solution properties.

[0031] Optionally, and particularly according to the first and second aspects of the present invention, the alloy may also contain at least one component for grain refinement, such as AlTiC or AlTiB2 (in the form of, for example, AT5B or AT3B), in an amount of 50 kg / ton or less each, preferably 20 kg / ton or less, more preferably 12 kg / ton or less, and 50 kg / ton or less in total, preferably 20 kg / ton or less.

[0032] A third aspect of the present invention is an alternative method that also solves the problem of crack susceptibility while maintaining excellent tensile mechanical performance in cold and hot conditions, for example at 200°C, without the need for solution treatment / quenching. This involves superimposed continuous layers of solid metal (201...20 n In a method for manufacturing a part including the formation of a solid layer (201...20), each layer is formed by the deposition of a metal (25) called a filler material, the filler material melts and solidifies upon energy supply to form the layer, the filler material is in the form of a powder (25), and as a result of exposing this powder to an energy beam (32), melting and subsequent solidification are brought about to form a solid layer (201...20n A method that will result in the formation of The filler material (25) is: - Zr in a mass fraction of 0.30% or more, preferably 0.30-2.50%, more preferably 0.40-2.00%, more preferably 0.40-1.80%, even more preferably 0.50-1.60%, even more preferably 0.60-1.50%, even more preferably 0.70-1.40%, and even more preferably 0.80-1.20%; - Sc less than 0.30%, preferably less than 0.20%, more preferably less than 0.10%, and more preferably less than 0.05% according to the mass fraction; - Mg in mass fraction of less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Zn in mass fraction less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Optionally, at least one element selected from Ni, Mn, Cr, and / or Cu, in mass fractions of 0.50 to 7.00%, preferably 1.00 to 6.00%, each; preferably, in mass fractions of less than 25.00%, more preferably less than 20.00%, and more preferably less than 15.00% in total; - Optionally, at least one element selected from Hf, Ti, Er, W, Nb, Ta, Y, Yb, Nd, Ce, Co, Mo, Lu, Tm, V and / or mischmetal, in a mass fraction of 5.00% or less for each element, preferably 3% or less, and a total of 15.00% or less, preferably 12% or less, and more preferably 5% or less; - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 1.00% or less, preferably 0.5% or less, more preferably 0.3% or less, more preferably 0.1% or less, even more preferably 700 ppm or less, and in a total of 2.00% or less, preferably 1% or less; - Optionally, according to the first modified form, the Fe content is 0.50 to 7.00%, preferably 1.00 to 6.00%, according to the mass fraction, or according to the second modified form, the Fe content is 1.00% or less, preferably 0.5% or less, preferably 0.3% or less, more preferably 0.1% or less, and even more preferably 700 ppm or less, according to the mass fraction; - Optionally, at least one element selected from Ag in mass fractions of 0.06 to 1.00% and / or Li in mass fractions of 0.06 to 1.00%; - Optionally, impurities less than 0.05% (i.e., 500 ppm) each by mass fraction, and less than 0.15% in total; - The remainder is aluminum; It is characterized by being an aluminum alloy containing at least the following alloying element; Furthermore, the method is characterized in that the components are manufactured at a temperature between 250°C and 350°C, preferably between 280°C and 330°C.

[0033] As mentioned above, it is known to those skilled in the art that other elements also have effects equivalent to those of Zr. In particular, Ti, V, Sc, Hf, Er, Tm, Yb, or Lu can be mentioned. Accordingly, according to one variant of the third subject of the present invention, Zr can be partially substituted by at least one element selected from Ti, V, Sc, Hf, Er, Tm, Yb, and Lu, preferably up to 90% of the mass fraction of Zr.

[0034] Therefore, the fourth object of the present invention is a continuous solid metal layer (201...20) superimposed on each other. nIn a method for manufacturing a part including the formation of a solid layer (201...20), each layer is formed by the deposition of a metal (25) called a filler material, the filler material melts and solidifies upon energy supply to form the layer, the filler material is in the form of a powder (25), and as a result of exposing this powder to an energy beam (32), melting and subsequent solidification are brought about to form a solid layer (201...20 n A method that will result in the formation of The filler material (25) is: - Knowing that Zr accounts for 10% to less than 100% of the following percentage range, at least one element selected from Ti, V, Sc, Hf, Er, Tm, Yb, and Lu and Zr, in total, according to mass fraction, is 0.30% or more, preferably 0.30-2.50%, more preferably 0.40-2.00%, more preferably 0.40-1.80%, even more preferably 0.50-1.60%, even more preferably 0.60-1.50%, even more preferably 0.70-1.40%, and even more preferably 0.80-1.20%; - Mg in mass fraction of less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Zn in mass fraction less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Optionally, at least one element selected from Ni, Mn, Cr, and / or Cu, in mass fractions of 0.50 to 7.00%, preferably 1.00 to 6.00%, each; preferably, in mass fractions of less than 25.00%, more preferably less than 20.00%, and more preferably less than 15.00% in total; - Optionally, at least one element selected from W, Nb, Ta, Y, Nd, Ce, Co, Mo and / or mischmetal, in a mass fraction of 5.00% or less for each element, preferably 3% or less, and a total of 15.00% or less, preferably 12% or less, and more preferably 5% or less; - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 1.00% or less, preferably 0.5% or less, more preferably 0.3% or less, more preferably 0.1% or less, even more preferably 700 ppm or less, and in a total of 2.00% or less, preferably 1% or less; - Optionally, according to the first modified form, the Fe content is 0.50 to 7.00%, preferably 1.00 to 6.00%, according to the mass fraction, or according to the second modified form, the Fe content is 1.00% or less, preferably 0.5% or less, preferably 0.3% or less, more preferably 0.1% or less, and even more preferably 700 ppm or less, according to the mass fraction; - Optionally, at least one element selected from Ag in mass fractions of 0.06 to 1.00% and / or Li in mass fractions of 0.06 to 1.00%; - Optionally, impurities less than 0.05% (i.e., 500 ppm) each by mass fraction, and less than 0.15% in total; - The remainder is aluminum; It is characterized by being an aluminum alloy containing at least the following alloying element; Furthermore, the method is characterized in that the components are manufactured at a temperature between 250°C and 350°C, preferably between 280°C and 330°C.

[0035] According to the present invention, the component is manufactured at a temperature of 25 to 150 °C, preferably 50 to 130 °C, more preferably 50 to 110 °C, even more preferably 80 to 110 °C, and even more preferably 80 to 105 °C, or at a temperature of more than 250 °C and less than 350 °C, preferably 280 to 330 °C. The selection of these two optimized temperatures is described in more detail in the following examples. There are multiple means for heating the manufacturing chamber (and thus the powder bed) for manufacturing components by additive manufacturing. For example, the use of an assembly heat tray, or heating by a laser, induction, heating lamp, or a heating element that can be installed under and / or inside the assembly tray and / or around the powder bed, etc., can be mentioned.

[0036] According to one embodiment, the method can be an assembly method with a high manufacturing speed. The manufacturing speed can be, for example, more than 4 mm 3 / s, preferably more than 6 mm 3 / s, and more preferably more than 7 mm 3 / s. The manufacturing speed is calculated as the product between the scan speed (in mm / s), the deviation vector (in mm), and the layer thickness (in mm).

[0037] According to one embodiment, the method can utilize one laser, optionally multiple lasers.

[0038] According to one embodiment, after the formation of the layer, - heat treatment at a temperature typically of at least 100 °C and at most 500 °C, preferably 300 to 450 °C; and / or - hot isostatic pressing (HIC); can be included.

[0039] The heat treatment can particularly enable the removal of residual stress and / or the additional precipitation of a hardened phase.

[0040] The HIC treatment can particularly enable the improvement of elongation characteristics and fatigue characteristics. The hot isostatic pressing can be carried out before, after, or instead of the heat treatment.

[0041] Advantageously, hot isostatic pressurization is carried out at a temperature of 250°C to 550°C, preferably 300°C to 450°C, and a pressure of 500 to 3000 bar for 0.5 to 10 hours.

[0042] According to another embodiment adapted to structurally hardened alloys, solution treatment followed by quenching and tempering and / or hot isostatic pressing of the formed part can be carried out. In this case, hot isostatic pressing can advantageously be substituted for solution treatment. However, the method according to the present invention is advantageous because it preferably does not require solution treatment and subsequent quenching. Solution treatment can adversely affect mechanical strength in some cases by contributing to an increase in dispersed phase or fine intermetallic phase. Moreover, on parts with complex shapes, quenching can lead to distortion of the part, which limits the first advantage of using additive manufacturing, which is that the part is obtained directly in its final or near-final shape.

[0043] According to one embodiment, the method according to the present invention further optionally includes machining and / or chemical, electrochemical or mechanical surface treatment and / or tribo-finishing. These treatments may be performed in particular to reduce roughness and / or improve corrosion resistance and / or improve resistance to fatigue crack initiation.

[0044] Optionally, mechanical deformation of the part may be carried out, for example, after additive manufacturing and / or before heat treatment.

[0045] Optionally, joining one or more other parts can be performed using known joining methods. For example, the following joining methods can be listed: - Bolt fastening, riveting, or other mechanical fastening methods; - fusion welding; - Friction welding; - Brazing.

[0046] The fifth object of the present invention is each 2.16 μm 2 A metal part obtained by the methods of the first and second subjects of the present invention, characterized in that the area fraction of equiaxed crystal grains having a surface area of ​​less than 44%, preferably less than 40%, and more preferably less than 36%; and the area fraction of columnar crystal grains is 22% or more, preferably 25% or more, and more preferably 30% or more.

[0047] The sixth object of the present invention is, - Zr in a mass fraction of 0.30-1.40%, preferably 0.40-1.40%, more preferably 0.50-1.40%, even more preferably 0.60-1.40%, even more preferably 0.70-1.40%, and even more preferably 0.80-1.20%; - Sc less than 0.30%, preferably less than 0.20%, more preferably less than 0.10%, and more preferably less than 0.05% according to the mass fraction; - Mg in mass fraction of less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Zn in mass fraction less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Optionally, at least one element selected from Ni, Mn, Cr, and / or Cu, in mass fractions of 0.50 to 7.00%, preferably 1.00 to 6.00%, each; preferably, in mass fractions of less than 25.00%, more preferably less than 20.00%, and more preferably less than 15.00% in total; - Optionally, at least one element selected from Hf, Ti, Er, W, Nb, Ta, Y, Yb, Nd, Ce, Co, Mo, Lu, Tm, V and / or mischmetal, in a mass fraction of 5.00% or less for each element, preferably 3% or less, and a total of 15.00% or less, preferably 12% or less, and more preferably 5% or less; - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 1.00% or less, preferably 0.5% or less, more preferably 0.3% or less, more preferably 0.1% or less, even more preferably 700 ppm or less, and in a total of 2.00% or less, preferably 1% or less; - Optionally, according to the first modified form, the Fe content is 0.50 to 7.00%, preferably 1.00 to 6.00%, according to the mass fraction, or according to the second modified form, the Fe content is 1.00% or less, preferably 0.5% or less, preferably 0.3% or less, more preferably 0.1% or less, and even more preferably 700 ppm or less, according to the mass fraction; - Optionally, at least one element selected from Ag in mass fractions of 0.06 to 1.00% and / or Li in mass fractions of 0.06 to 1.00%; - Optionally, impurities less than 0.05% (i.e., 500 ppm) each by mass fraction, and less than 0.15% in total; - The remainder is aluminum; The powder preferably consists of an aluminum alloy containing at least the alloying element.

[0048] As mentioned above, it is known to those skilled in the art that other elements also have effects equivalent to those of Zr. In particular, Ti, V, Sc, Hf, Er, Tm, Yb, or Lu can be mentioned. Accordingly, according to one variant of the powdered aluminum alloy according to the present invention, Zr can be partially replaced by at least one element selected from Ti, V, Sc, Hf, Er, Tm, Yb, and Lu, preferably up to 90% of the mass fraction of Zr.

[0049] Therefore, the seventh object of the present invention is, - Knowing that Zr accounts for 10% to less than 100% of the following percentage range, at least one element selected from Ti, V, Sc, Hf, Er, Tm, Yb, and Lu, and Zr, in total, according to mass fraction, of 0.30-1.40%, preferably 0.40-1.40%, more preferably 0.50-1.40%, even more preferably 0.60-1.40%, even more preferably 0.70-1.40%, and even more preferably 0.80-1.20%; - Mg in mass fraction of less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Zn in mass fraction less than 2.00%, preferably less than 1.00%, more preferably less than 0.50%, more preferably less than 0.30%, even more preferably less than 0.10%, and even more preferably less than 0.05%; - Optionally, at least one element selected from Ni, Mn, Cr, and / or Cu, in mass fractions of 0.50 to 7.00%, preferably 1.00 to 6.00%, each; preferably, in mass fractions of less than 25.00%, more preferably less than 20.00%, and more preferably less than 15.00% in total; - Optionally, at least one element selected from W, Nb, Ta, Y, Nd, Ce, Co, Mo and / or mischmetal, in a mass fraction of 5.00% or less for each element, preferably 3% or less, and a total of 15.00% or less, preferably 12% or less, and more preferably 5% or less; - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 1.00% or less, preferably 0.5% or less, more preferably 0.3% or less, more preferably 0.1% or less, even more preferably 700 ppm or less, and in a total of 2.00% or less, preferably 1% or less; - Optionally, according to the first modified form, the Fe content is 0.50 to 7.00%, preferably 1.00 to 6.00%, according to the mass fraction, or according to the second modified form, the Fe content is 1.00% or less, preferably 0.5% or less, preferably 0.3% or less, more preferably 0.1% or less, and even more preferably 700 ppm or less, according to the mass fraction; - Optionally, at least one element selected from Ag in mass fractions of 0.06 to 1.00% and / or Li in mass fractions of 0.06 to 1.00%; - Optionally, impurities less than 0.05% (i.e., 500 ppm) each by mass fraction, and less than 0.15% in total; - The remainder is aluminum; The powder preferably consists of an aluminum alloy containing at least the alloying element.

[0050] Preferably, the powder and alternative alloys according to the present invention contain at least 80%, more preferably at least 85%, of aluminum by mass.

[0051] Preferably, the aluminum alloy in powder form (subjects of the 6th and 7th parts of the present invention) and by alternative methods (subjects of the 3rd and 4th parts of the present invention) is: - Zr in a mass fraction of 0.50-3.00%, preferably 0.50-2.50%, more preferably 0.60-1.40%, more preferably 0.70-1.30%, even more preferably 0.80-1.20%, even more preferably 0.85-1.15%, and even more preferably 0.90-1.10%; - Mn in a mass fraction of 1.00 to 7.00%, preferably 1.00 to 6.00%, more preferably 2.00 to 5.00%; more preferably 3.00 to 5.00%, and even more preferably 3.50 to 4.50%; - Ni in a mass fraction of 1.00 to 6.00%, preferably 1.00 to 5.00%, more preferably 2.00 to 4.00%, and more preferably 2.50 to 3.50%; - Optionally, according to mass fraction, 1.00% or less, preferably 0.50% or less, preferably 0.30% or less; and preferably 0.05% or more, preferably 0.10% or more of Fe; - Optionally, Si in an amount of 1.00% or less, preferably 0.50% or less, according to the mass fraction; - Optionally, 1.00 to 5.00%, preferably 1.00 to 3.00%, and more preferably 1.50 to 2.50% of Cu, according to mass fraction; Includes.

[0052] The aluminum alloy powder and alternative methods according to the present invention may optionally contain at least one component selected for grain refinement, such as AlTiC or AlTiB2 (in the form of, for example, AT5B or AT3B), in an amount of 50 kg / ton or less for each component, preferably 20 kg / ton or less, more preferably 12 kg / ton or less, and 50 kg / ton or less in total, preferably 20 kg / ton or less.

[0053] Preferably, the addition of La, Bi, Mg, Er, Yb, Y, Sc, and / or Zn is avoided, and the preferred mass fraction of each of these elements is less than 0.05%, preferably less than 0.01%. According to another embodiment, the addition of Fe and / or Si is avoided. However, it is known to those skilled in the art that these two elements are generally present in common aluminum alloys in the amounts described above. Thus, the amounts described above may also correspond to the impurity amounts of Fe and Si.

[0054] Other advantages and features will become clearer from the following description and non-limiting examples, as illustrated in the figures listed below. [Brief explanation of the drawing]

[0055] [Figure 1] This figure illustrates an additive manufacturing method of the SLM or EBM type. [Figure 2]The crack test specimens used in the examples are shown. Reference numeral 1 corresponds to the plane used for metallographic observation, reference numeral 2 corresponds to the critical zone for crack measurement, and reference numeral 3 corresponds to the manufacturing direction. [Figure 3] This is the geometry of the test specimen used to perform the tensile tests used in the examples. [Modes for carrying out the invention]

[0056] Unless otherwise specified in the specification: - The designations for aluminum alloys shall conform to the terminology established by the Aluminum Association; - The content of chemical elements is indicated in percentages and represents mass fractions.

[0057] Figure 1 generally illustrates one embodiment in which the additive manufacturing method according to the present invention is used. According to this method, the filler material 25 is in the form of an alloy powder according to the present invention. An energy source, such as a laser source or electron source 31, emits an energy beam, such as a laser beam or electron beam 32. The energy source is coupled to the filler material by an optical system or electromagnetic lens system 33, so that the movement of the beam can be determined according to a digital model M. The energy beam 32 follows a movement along the longitudinal plane XY, drawing a pattern according to the digital model M. The powder 25 is placed on an assembly tray 10. The interaction between the energy beam 32 and the powder 25 produces selective melting and subsequent solidification of the powder, resulting in layers 201...20 nThis results in the formation of a layer. Once the layer is formed, it is coated with filler powder 25, forming another layer superimposed on the pre-fabricated layer. The thickness of the powder forming the layer can be, for example, 10 to 200 μm. This additive manufacturing method is typically known as selective laser melting (SLM) when the energy beam is a laser beam, in which case the method is advantageously performed at atmospheric pressure, and as electron beam melting (EBM) when the energy beam is an electron beam, in which case the method is advantageously typically performed at a reduced pressure of less than 0.01 bar, and preferably less than 0.1 mbar.

[0058] In another embodiment, the layer is obtained by selective laser sintering (selective laser sintering, SLS, or direct metal laser sintering, DMLS), and the alloy powder layer according to the present invention is selectively sintered according to a selected digital model using thermal energy supplied by a laser beam.

[0059] In another embodiment not shown in Figure 1, the powder is generally melted simultaneously with the introduction of a laser beam. This method is known as laser melting deposition (laser melting deposition).

[0060] Other methods, particularly those known as Direct Energy Deposition (DED), Direct Metal Deposition (DMD), Direct Laser Deposition (DLD), Laser Deposition Technology (LDT), Laser Metal Deposition (LMD), Laser Engineering Net Shaping (LENS), Laser Cladding Technology (LCT), or Laser Freeform Manufacturing Technology (LFMT), may be used.

[0061] In one embodiment, the method according to the present invention is used for the production of a hybrid part comprising a portion obtained by conventional rolling and / or extrusion and / or casting and / or forging and optionally subsequent machining, and a strongly bonded portion obtained by additive manufacturing. This embodiment may also be suitable for repairing parts obtained by conventional methods.

[0062] Furthermore, in one embodiment of the present invention, the method according to the present invention can also be used to repair a part obtained by additive manufacturing.

[0063] After the formation of continuous layers, an unprocessed part, that is, a part in its unprocessed state before manufacturing, is obtained.

[0064] According to one embodiment, the elastic limit measured at ambient temperature of an unprocessed part obtained according to the present invention is less than 450 MPa, preferably less than 400 MPa, more preferably 200 to 400 MPa, and even more preferably 200 to 350 MPa.

[0065] According to one embodiment, the elastic limit measured at ambient temperature of a part according to the present invention after heat treatment, without solution treatment or quenching, is higher than the elastic limit of the same part in its unprocessed state. Preferably, the elastic limit measured at ambient temperature of a part according to the present invention after heat treatment, as described above, is greater than 350 MPa, and more preferably greater than 400 MPa.

[0066] According to one embodiment, the elastic limit of a component measured at high temperatures remains high. In fact, for a component in its unprocessed state or after stress relief treatment at temperatures below 350°C, the elastic limit measured at 200°C remains more than 50%, preferably more than 60%, of the elastic limit measured at ambient temperature.

[0067] The powder used in accordance with the present invention may have at least one of the following characteristics: - Average particle size of 3 to 100 μm, preferably 5 to 25 μm, or 20 to 60 μm. The values ​​shown mean that at least 80% of the particles have an average particle size within the specified range; - Spherical. The sphericity of a powder can be determined, for example, using a morphogranulometer; - Excellent castability. The castability of the powder can be determined, for example, according to ASTM B213 or ISO 4490:2018 standards. According to ISO 4490:2018, the flow time is preferably less than 50 seconds; - Preferably a low porosity of 0-5 volume%, more preferably 0-2 volume%, and even more preferably 0-1 volume%. Porosity can be determined in particular by scanning electron microscopy or helium pycnometry (see ASTM B923 standard); - Absence or small amount (less than 10% by volume, preferably less than 5% by volume) of smaller particles called satellite particles (1-20% of the average size of the powder) that adhere to larger particles.

[0068] The powder used according to the present invention can be obtained from the alloy according to the present invention in liquid or solid form by conventional atomization methods. Alternatively, the powder can also be obtained by mixing the primary powder with various compositions of primary powder having an average composition corresponding to the composition of the alloy according to the present invention, before exposure to an energy beam.

[0069] Before the powder is atomized and / or during the deposition of the powder and / or during the mixing of the primary powder, insoluble and non-fusible particles, such as oxides, or titanium diboride (TiB2) particles or titanium carbide (TiC) particles may be added to the bath. These particles may help to refine the microstructure. These particles may also help to harden the alloy if they are nanometer-sized. These particles may be present in a volume fraction of less than 30%, preferably less than 20%, and more preferably less than 10%.

[0070] The powder according to the present invention can be obtained, for example, by gas jet spraying, plasma spraying, water jet spraying, ultrasonic spraying, centrifugal spraying, electrolysis and spheroidization, or pulverization and spheroidization.

[0071] Preferably, the powder according to the present invention is obtained by gas jet spraying. The gas jet spraying method begins with the pouring of molten metal through a nozzle. Next, a neutral gas such as nitrogen or argon, which may be accompanied by other gases, reaches the molten metal, and this metal is atomized into very small droplets, which solidify as they cool and fall into the inside of the atomization tower. The powder is then collected in a can. The gas jet spraying method has the advantage of producing spherical powder, unlike water jet spraying which produces powder with an irregular shape. Another advantage of gas jet spraying is its excellent powder density, particularly due to its spherical shape and particle size distribution. Yet another advantage of this method is the excellent reproducibility of the particle size distribution.

[0072] The powder according to the present invention can be placed in a constant-temperature oven after its manufacture, particularly for the purpose of reducing its moisture content. The powder can also be packaged and stored between its manufacture and use.

[0073] The powder according to the present invention can be used in the following fields of application: - Selective laser sintering (SLS); - Direct Metal Laser Sintering (DMLS); - Selective Heat Sintering (SHS); - Selective laser melting (SLM); - Electron beam melting (EBM); - Laser melting deposition; - Direct Energy Deposition (DED); - Direct Metal Deposition (DMD); - Direct laser deposition (DLD); - Laser deposition technology (LDT); - Laser Engineering Net Shaping (or LENS in English); - Laser cladding technology (LCT); - Laser Freeform Manufacturing Technology (LFMT); - Laser Metal Deposition (LMD); - Cold Spray Consolidation (CSC); - Additive friction stir (AFS); - Field-assisted sintering technology or spark plasma sintering (FAST or spark plasma sintering); or - Inertia Rotary Friction Welding (IRFW).

[0074] The present invention is described in further detail in the following embodiments.

[0075] The present invention is not limited to the embodiments described above or in the following examples, and can vary considerably within the scope of the invention as defined by the claims appended to this specification.

[0076] [Examples] Example 1: The first study was conducted on alloy A, having the composition shown in Table 1 below, which was determined in mass percent by ICP (Inductively Coupled Plasma). This alloy was obtained in powder form for the SLM method using gas (Ar) jet spraying. The particle size was essentially 3 μm to 100 μm, with D10 being approximately 35 μm, D50 approximately 48 μm, and D90 approximately 67 μm.

[0077] [Table 1]

[0078] Using an EOS290 (supplier EOS) type SLM machine, crack test specimens were prepared to study the susceptibility of this alloy to cracking.

[0079] The specimens shown in Figure 2 have a special geometry that includes a hazardous area prone to cracking. This hazardous area has a radius of curvature R. The main laser parameters used during the printing of these specimens were as follows: laser power 370W; scan speed 1400mm / s; deviation vector 0.11mm; layer thickness 60μm. The machine used, EOSM290, can heat the assembly tray to a temperature of 200°C using a heating element. Using this machine, crack test specimens were printed at tray temperatures of 50°C, 80°C, 100°C, and 200°C. In all cases, the specimens underwent stress relief treatment at 300°C for 4 hours after manufacturing.

[0080] After manufacturing, the test specimens were mechanically polished to a level of 1 μm on the surface shown in Figure 2 (reference number 1). The total length of the crack present at the critical starting point of the test specimen was measured using an optical microscope at 50x magnification. The results are summarized in Table 2 below.

[0081] [Table 2]

[0082] The results of this first study show that a decrease in tray temperature between 200°C and 50°C is advantageous in reducing the crack susceptibility of alloy A. This result contradicts several literature studies (see the preceding prior art section herein) that demonstrate the beneficial effect of preheating assembly trays above 150°C, and even above 350°C, on cracking during the SLM method.

[0083] It should be noted that in this embodiment, in order to effectively compare the effect of assembly tray temperature on crack susceptibility, the inventors intentionally placed the test specimens under conditions that would promote cracking. If test specimens with less complex shapes had been used, sufficient distinction would not have been possible. Therefore, this embodiment is useful only for demonstrating the effect of assembly tray temperature on crack susceptibility.

[0084] Within the scope of supplementary tests not shown herein, using the composition according to the present invention on another SLM machine with a heating tray up to 500°C, the inventors demonstrated that tray temperatures of 250–350°C, and preferably 280–330°C, also allow for the avoidance of cracking on crack test specimens without degrading the mechanical properties at ambient temperature and 200°C. Surprisingly, despite the increase in tray temperature, there was no decrease in mechanical properties in the unprocessed state or after heat treatment. Without being constrained by theory, it appears that under these conditions the alloy according to the present invention can maintain excellent suitability for the capture of additive elements, and in particular Zr, in solid solutions. For example, further increases in tray temperature to 400°C or 500°C would likely reduce the solidification rate during the SLM method, thus limiting the capture of Zr in solid solutions, which would likely reduce the mechanical properties in the unprocessed state and the suitability for further hardening of the alloy during heat treatment, for example, at 400°C after production. In conclusion, the temperature range for trays that appears to maximize crack susceptibility is between 150°C and 250°C.

[0085] Therefore, the recommended temperature range for the assembly tray according to the present invention is 25 to 150°C, preferably 50 to 130°C, more preferably 80 to 110°C, even more preferably 80 to 105°C, or a temperature between 250°C and less than 350°C, preferably 280 to 330°C.

[0086] Example 2: This study aimed to determine the effect of the temperature of the assembly tray on the ambient temperature and the tensile mechanical properties at 200°C of parts obtained by additive manufacturing. For this purpose, alloy A from Example 1 was used.

[0087] Cylindrical samples perpendicular to the assembly direction (direction Z) were fabricated using an EOS M290 (supplier EOS) type SLM machine to determine the mechanical properties of the alloy. These samples had a diameter of 11 mm and a height of 46 mm. The main laser parameters used during the printing of these samples were as follows: laser power 370 W; scan speed 1400 mm / s; deviation vector 0.11 mm; layer thickness 60 μm. Two temperatures, 100°C and 200°C, were tested for the assembly tray.

[0088] In all cases, the samples underwent a post-manufacturing stress relief treatment at 300°C for 4 hours.

[0089] A cylindrical sample was machined to obtain a tensile test specimen having the following properties as described in Table 3 and Figure 3 below.

[0090] [Table 3]

[0091] In Table 3 and Figure 3 above, φ represents the diameter of the central part of the specimen; M represents the width of both ends of the specimen; LT represents the total length of the specimen; R represents the radius of curvature between the central part and the ends of the specimen; Lc represents the length of the central part of the specimen; and F represents the length of both ends of the specimen.

[0092] After machining, several test pieces were subjected to a heat treatment at 400°C for 1 hour. This 400°C 1-hour heat treatment simulates post-manufacturing processes such as long-term aging or hot isostatic processing at the final part's operating temperature of 100°C to 300°C.

[0093] The test specimens were then subjected to tensile tests at ambient temperature (25°C) according to the NF EN ISO 6892-1 (2009-10) standard and at high temperature (200°C) according to the NF EN ISO 6892-2 (2018) standard. The main results are summarized in Table 4 below.

[0094] [Table 4]

[0095] Of the two temperatures (100°C and 200°C) tested for the assembly trays, 100°C appears to be more favorable. In fact, the 100°C temperature for the assembly trays resulted in better mechanical properties under all tested conditions, except for the tensile test conducted at 25°C for the unprocessed, stress-relieved state (no post-manufacturing heat treatment at 400°C).

[0096] However, the more flexible stress-relieving unprocessed state in tensile stress at 25°C is also advantageous because it contributes to lower residual stress levels during SLM part manufacturing, resulting in fewer distortion problems in the final part.

[0097] For two temperatures tested in the assembly trays, post-manufacturing treatment at 400°C for 1 hour allowed for a significant increase in the elastic limit at 25°C compared to the untreated stress-relieving state (no post-manufacturing heat treatment at 400°C). This type of post-manufacturing treatment is advantageous for maximizing the elastic limit in application areas where parts are worked at ambient temperatures or temperatures below 150°C.

[0098] Conversely, for the two temperatures tested for the manufacturing trays, post-manufacturing treatment at 400°C for one hour resulted in a decrease of approximately 26 MPa in the elastic limit at 200°C compared to the untreated stress-relieving state (no post-manufacturing heat treatment at 400°C). For so-called "high-temperature" applications, i.e., parts working at temperatures above approximately 200°C or more commonly above 150°C, the untreated stress-relieving state appears to be advantageous.

[0099] Example 3: Cracking test specimens identical to those in Example 1 were prepared from alloy A described in Example 1 and alloys F and H described in Table 5 below. Alloys F and H were also obtained in powder form for the SLM method using gas (argon) jet spraying. The particle sizes were essentially 3 μm to 100 μm, 9 to 30 μm for D10, 25 to 44 μm for D50, and 51 to 64 μm for D90.

[0100] [Table 5]

[0101] The laser parameters used were the same as those in Example 1: laser power 370 W; scan speed 1400 mm / s; deviation vector 0.11 mm; layer thickness 60 μm. The assembly trays were heated to 200°C for alloy A and to 100°C for alloys F and H. The test specimens were subjected to a post-manufacturing stress relief treatment at 300°C for 4 hours.

[0102] As described in Example 1, the total length of the crack present at the crack risk site of the crack test specimen was determined for each alloy.

[0103] Granular structure characterization was also performed for all samples using EBSD (Electron Back Scattered Diffraction) with an EDAX camera and OIM (Orientation Imaging Microscopy) software. These characterizations were performed using a ZEISS Ultra55 type FEG-SEM at an energy of 15 keV in a 500 μm × 500 μm field with a pitch of 0.5 μm.

[0104] Prior to EBSD characterization, all samples were subjected to conventional mechanical polishing down to 1 μm (sandpaper with water lubrication, followed by polishing cloth with diamond suspension), and then polished by vibration at 30% amplitude for 6 hours using a 50% diluted SPM (colloidal silica gel) solution in water as a lubricant.

[0105] For all samples, the total surface fraction of crystal grains with a surface area exceeding a given threshold was calculated. Multiple thresholds were used, namely 2.16 μm. 2 , 3.24 μm 2 , 6.48 μm 2 , 8.64 μm 2 and 10.8 μm 2 The following was used. The results are shown in Table 6 below.

[0106] [Table 6]

[0107] The results in Table 6 above are for 2.16 μm each. 2 This indicates that a total surface area fraction of crystal grains having a surface area exceeding 56%, preferably exceeding 60%, and more preferably exceeding 64%, is advantageous for completely eliminating cracking during the SLM method.

[0108] In other words, to avoid cracking during the SLM method, each should be 2.16 μm. 2 A total area fraction of less than 44%, preferably less than 40%, and more preferably less than 36% of fine crystal grains having a surface area of ​​less than 1 is advantageous. These fine crystal grains had an equiaxed structure.

[0109] The results in Table 6 above are for 3.24 μm each. 2 This indicates that a total surface area fraction of crystal grains having a surface area exceeding 48%, preferably exceeding 52%, and more preferably exceeding 57%, is advantageous for completely eliminating cracking during the SLM method.

[0110] The results in Table 6 above are for 6.48 μm each. 2 This indicates that a total surface area fraction of crystal grains having a surface area exceeding 27%, preferably exceeding 35%, and more preferably exceeding 40%, is advantageous for completely eliminating cracking during the SLM method.

[0111] The results in Table 6 above are for 8.64 μm each.2 This indicates that a total surface area fraction of crystal grains having a surface area of ​​more than 22%, preferably more than 27%, and more preferably more than 33%, is advantageous for completely eliminating cracking during the SLM method.

[0112] The results in Table 6 above are for 10.8 μm each. 2 This indicates that a total surface area fraction of crystal grains having a surface area of ​​more than 19%, preferably more than 25%, and more preferably more than 30%, is advantageous for completely eliminating cracking during the SLM method.

[0113] The measured area fractions of columnar grains were 22% for alloy A, 39% for alloy F, and 60% for alloy H. This measurement was performed using OIM software, taking into account grains with an elongation ratio (ratio between length and width) of 3 or more. The results indicate that a granular structure with a columnar grain fraction of 22% or more, preferably 25% or more, and even more preferably 30% or more, is advantageous for eliminating cracks during the SLM method.

[0114] The columnar grains without cracks generally have a length of less than 500 μm, preferably less than 300 μm, more preferably less than 200 μm, and even more preferably less than 150 μm. The columnar grains generally have a width of less than 150 μm, preferably less than 100 μm, preferably less than 50 μm, more preferably less than 30 μm, and even more preferably less than 20 μm.

[0115] Therefore, the granular structure required to limit cracking is a surface fraction of more than 22% columnar grains and a grain size of 2.16 μm each. 2 It appears to be a structure with a surface area fraction of less than 44% of fine equiaxed crystal grains having a surface area of ​​less than 44%.

[0116] This result contradicts prior art in the development of aluminum alloys for SLM applications, strongly prompting the search for perfectly equiaxed fine structures to eliminate solidification cracking in aluminum alloys during SLM manufacturing. This equiaxed structure can be obtained, in particular, by introducing different types of crystal nuclei or nucleation, as exemplified, for example, in U.S. Patent Application Publication No. 2020 / 024700; U.S. Patent Application Publication No. 2018 / 161874; Martin et al.: September 2017, vol. 549, NATURE 365, “3D printing of high-strength aluminum alloys”.

[0117] In supplementary tests, the inventors demonstrated that the presence of Mg can induce the formation of microcracks in samples having a predominantly columnar structure. These microcracks propagate parallel to the columnar grains at grain boundaries. The presence of Mg can also lead to the generation of smoke during the SLM method, posing a risk of laser instability. Therefore, in one variant of the present invention, the Mg content is preferably less than 2%, more preferably less than 1%, and more preferably less than 0.05%. [Explanation of Symbols]

[0118] 1. Surface used for metallographic observation. 2. Critical zone for measuring cracks 3 Manufacturing direction 10 Assembly Trays 25 powder 31 Energy sources 32 Energy beams 33 Optical or electromagnetic lens systems

Claims

1. A continuous layer of solid metals superimposed on each other (20 １ ...20 ｎ In a method for manufacturing a part, including the formation of a solid layer (20), each layer is formed by the deposition of a metal (25) called a filler material, the filler material melts and solidifies upon energy supply to form the layer, the filler material is in the form of a powder (25), and as a result of exposing this powder to an energy beam (32), melting and subsequent solidification are brought about to form a solid layer (20 １ ...20 ｎ A method that will result in the formation of The components are characterized by being manufactured at temperatures ranging from 25 to 150°C. Furthermore, each component is 2.16 μm ２ It is characterized by having a grain structure in which the area fraction of equiaxed grains with a surface area of ​​less than 44% is less than 44%, and a grain structure in which the area fraction of columnar grains is 22% or more. Furthermore, the filler material (25) - According to the mass fraction, 0.30 to 2.50% Zr, - According to the mass fraction, less than 0.30% Sc, - Mg less than 0.50% according to mass fraction, - According to the mass fraction, less than 0.50% Zn, - Optionally, at least one element selected from Ni, Mn, and / or Cu, in mass fractions of 1.00 to 6.00% each, and less than 15.00% in total. - Optionally, at least one element selected from Hf, Ti, Er, W, Nb, Ta, Y, Yb, Nd, Ce, Co, Mo, Lu, Tm, V and / or mischmetal, in a mass fraction of 3% or less for each element and 5% or less in total. - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 0.5% or less for each element and 1% or less in total. - Optionally, according to the first modified form, 1.00 to 6.00% of Fe according to the mass fraction, or according to the second modified form, 0.5% or less of Fe according to the mass fraction. - Optionally, at least one element selected from 0.06 to 1.00% by mass fraction of Ag and / or 0.06 to 1.00% by mass fraction of Li, - Optionally, impurities may be present in amounts of less than 0.05% (i.e., 500 ppm) each, and in total less than 0.15% according to their mass fraction. - The remainder is aluminum A method characterized by using an aluminum alloy consisting of the following.

2. A method of manufacturing a component including the formation of successive solid metal layers (20 １ ... 20 ｎ ) in which each layer depicts a pattern defined from a digital model (M), each layer being formed by the deposition of a metal (25) called a filler material, the filler material being adapted to constitute said layer by receiving an energy supply and melting and solidifying, the filler material being in the form of a powder (25), and melting and subsequent solidification being brought about as a result of exposing this powder to an energy beam (32) to form a solid layer (20 １ ... 20 ｎ ), the method being The components are characterized by being manufactured at temperatures ranging from 25 to 150°C. Furthermore, each component is 2.16 μm ２ It is characterized by having a grain structure in which the area fraction of equiaxed grains with a surface area of ​​less than 44% is less than 44%, and a grain structure in which the area fraction of columnar grains is 22% or more. Furthermore, the filler material (25) - Knowing that Zr accounts for 10% to less than 100% of the following percentage range, according to the mass fraction, the sum of at least one element selected from Ti, V, Sc, Hf, Er, Tm, Yb, and Lu, totaling 0.30 to 2.50%, and Zr, - Mg less than 0.50% according to mass fraction, - According to the mass fraction, less than 0.50% Zn, - Optionally, at least one element selected from Ni, Mn, and / or Cu, in mass fractions of 1.00 to 6.00% each, and less than 15.00% in total. - Optionally, at least one element selected from W, Nb, Ta, Y, Nd, Ce, Co, Mo and / or mischmetal, in a mass fraction of 3% or less for each element and 5% or less in total. - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 0.5% or less for each element and 1% or less in total. - Optionally, according to the first modified form, 1.00 to 6.00% of Fe according to the mass fraction, or according to the second modified form, 0.5% or less of Fe according to the mass fraction. - Optionally, at least one element selected from 0.06 to 1.00% by mass fraction of Ag and / or 0.06 to 1.00% by mass fraction of Li, - Optionally, impurities may be present in amounts of less than 0.05% (i.e., 500 ppm) each, and in total less than 0.15% according to their mass fraction. - The remainder is aluminum A method characterized by using an aluminum alloy consisting of the following.

3. The method according to claim 1 or 2, wherein the component is manufactured at a temperature of 50 to 130°C.

4. A continuous layer of solid metals superimposed on each other (20 １ ...20 ｎ In a method for manufacturing a part, including the formation of a solid layer (20), each layer is formed by the deposition of a metal (25) called a filler material, the filler material melts and solidifies upon energy supply to form the layer, the filler material is in the form of a powder (25), and as a result of exposing this powder to an energy beam (32), melting and subsequent solidification are brought about to form a solid layer (20 １ ...20 ｎ A method that will result in the formation of The filler material (25) - According to the mass fraction, 0.30 to 2.50% Zr, - According to the mass fraction, less than 0.30% Sc, - Mg less than 0.50% according to mass fraction, - According to the mass fraction, less than 0.50% Zn, - Optionally, at least one element selected from Ni, Mn, and / or Cu, in mass fractions of 1.00 to 6.00% each, and less than 15.00% in total. - Optionally, at least one element selected from Hf, Ti, Er, W, Nb, Ta, Y, Yb, Nd, Ce, Co, Mo, Lu, Tm, V and / or mischmetal, in a mass fraction of 3% or less for each element and 5% or less in total. - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 0.5% or less for each element and 1% or less in total. - Optionally, according to the first modified form, 1.00 to 6.00% of Fe according to the mass fraction, or according to the second modified form, 0.5% or less of Fe according to the mass fraction. - Optionally, at least one element selected from 0.06 to 1.00% by mass fraction of Ag and / or 0.06 to 1.00% by mass fraction of Li, - Optionally, impurities may be present in amounts of less than 0.05% (i.e., 500 ppm) each, and in total less than 0.15% according to their mass fraction. - The remainder is aluminum It is characterized by being an aluminum alloy consisting of the following: Furthermore, the method is characterized in that the components are manufactured at a temperature between 250°C and 350°C.

5. A continuous layer of solid metals superimposed on each other (20 １ ...20 ｎ In a method for manufacturing a part, including the formation of a solid layer (20), each layer is formed by the deposition of a metal (25) called a filler material, the filler material melts and solidifies upon energy supply to form the layer, the filler material is in the form of a powder (25), and as a result of exposing this powder to an energy beam (32), melting and subsequent solidification are brought about to form a solid layer (20 １ ...20 ｎ A method that will result in the formation of The filler material (25) - Knowing that Zr accounts for 10% to less than 100% of the following percentage range, according to the mass fraction, the sum of at least one element selected from Ti, V, Sc, Hf, Er, Tm, Yb, and Lu, totaling 0.30 to 2.50%, and Zr, - Mg less than 0.50% according to mass fraction, - According to the mass fraction, less than 0.50% Zn, - Optionally, at least one element selected from Ni, Mn, and / or Cu, in mass fractions of 1.00 to 6.00% each, and less than 15.00% in total. - Optionally, at least one element selected from W, Nb, Ta, Y, Nd, Ce, Co, Mo and / or mischmetal, in a mass fraction of 3% or less for each element and 5% or less in total. - Optionally, at least one element selected from Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and / or Sn, in a mass fraction of 0.5% or less for each element and 1% or less in total. - Optionally, according to the first modified form, 1.00 to 6.00% of Fe according to the mass fraction, or according to the second modified form, 0.5% or less of Fe according to the mass fraction. - Optionally, at least one element selected from 0.06 to 1.00% by mass fraction of Ag and / or 0.06 to 1.00% by mass fraction of Li, - Optionally, impurities may be present in amounts of less than 0.05% (i.e., 500 ppm) each, and in total less than 0.15% according to their mass fraction. - The remainder is aluminum It is characterized by being an aluminum alloy consisting of the following: Furthermore, the method is characterized in that the components are manufactured at a temperature between 250°C and 350°C.

6. Aluminum alloy, - According to the mass fraction, 0.50 to 2.50% Zr, - According to the mass fraction, 1.00 to 6.00% Mn, - According to the mass fraction, 1.00 to 6.00% Ni, - Optionally, according to the mass fraction, Fe at a concentration of 0.50% or less. - Optionally, according to the mass fraction, 0.50% or less of Si, - Optionally, 1.00 to 5.00% Cu according to the mass fraction. The method according to any one of claims 1 to 5, including the method described above.

7. layer (20 １ ...20 ｎ After the formation of ) - Typically, heat treatment at a temperature of at least 100°C and more often 500°C, and / or - Hot isostatic pressurization, The method according to any one of claims 1 to 6, including the method described above.

8. The method according to any one of claims 1 to 7, wherein the addition of La, Bi, Mg, Er, Yb, Y, Sc and / or Zn is avoided, and the mass fraction of each of these elements is less than 0.05%.

9. The method according to any one of claims 1 to 8, wherein the aluminum alloy also comprises at least one component for refining the crystal grains, for example, AlTiC or AlTiB2, in an amount of 50 kg / ton or less for each component and 50 kg / ton or less in total.

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