Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/20—Direct sintering or melting
  • B22F10/28—Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/30—Process control
  • B22F10/36—Process control of energy beam parameters
  • B22F10/362—Process control of energy beam parameters for preheating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/60—Treatment of workpieces or articles after build-up
  • B22F10/64—Treatment of workpieces or articles after build-up by thermal means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
  • B22F12/10—Auxiliary heating means
  • B22F12/17—Auxiliary heating means to heat the build chamber or platform
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y10/00—Processes of additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y40/00—Auxiliary operations or equipment, e.g. for material handling
  • B33Y40/20—Post-treatment, e.g. curing, coating or polishing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y70/00—Materials specially adapted for additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y80/00—Products made by additive manufacturing
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/0408—Light metal alloys
  • C22C1/0416—Aluminium-based alloys
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/05—Metallic powder characterised by the size or surface area of the particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/06—Metallic powder characterised by the shape of the particles
  • B22F1/065—Spherical particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2301/00—Metallic composition of the powder or its coating
  • B22F2301/05—Light metals
  • B22F2301/052—Aluminium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/25—Process efficiency

Definitions

• the technical field of the invention is a process for manufacturing an aluminum alloy part, implementing an additive manufacturing technique.
• additive manufacturing techniques consist of shaping a part by adding material, as opposed to machining techniques, which aim to remove material.
• machining techniques which aim to remove material.
• additive manufacturing is defined according to the French standard XP E67-001: “set of processes making it possible to manufacture, layer by layer, by adding material, a physical object from a digital object”.
• the ASTM F2792-10 standard 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, has been described in document WO2015006447.
• the application of successive layers is generally carried out by applying a so-called filler material, then melting or sintering the filler material using an energy source such as a laser beam, electron beam, plasma torch or electric arc.
• 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. It can be melting or laser sintering.
• Patent application US20170016096 describes a process for manufacturing a part by localized melting obtained by exposing a powder to an energy beam of the electron beam or laser beam type, the process also being designated by the acronyms Anglo-Saxon SLM, meaning "Selective Laser Melting" or LPBF "Laser Powder Bed Fusion” or EBM, meaning "Electro Beam Melting".
• each layer a thin layer of powder is placed on a support, for example taking the form of a tray.
• the powder thus forms a powder bed.
• the energy beam sweeps the powder.
• the scan is performed according to a predetermined digital pattern. Scanning allows the formation of a layer by fusion/solidification of the powder. Following the formation of the layer, the latter is covered with a new thickness of powder. The process of forming successive layers, superimposed on each other, is repeated until the final piece is obtained.
• 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 on the heat treatments applied following the implementation of additive manufacturing. It has for example been shown that the addition of elements such as Mn and/or Ni and/or Zr and/or Cu can make it possible to improve the mechanical properties of the part resulting from additive manufacturing.
• the powder bed, subjected to exposure to the laser beam is brought to a temperature of the order of 200° C.
• the aforementioned publication indicates that by preheating an aluminum alloy powder to a temperature above 150° C., the distortions can be reduced, compared to a process implemented without preheating This publication concludes that the optimum temperature for preheating the powder is at 250°C.
• the preheating temperature has an influence on the properties of resistance to cracking of parts manufactured by additive manufacturing, on the basis of an aluminum alloy.
• the preheat temperature By selecting the preheat temperature, and implementing an appropriate post-fabrication heat treatment, the crack resistance can be significantly improved. This is the object of the invention described below.
• a first object of the invention is a process for manufacturing a part comprising forming successive metal layers, superimposed on each other, each layer describing a pattern defined from a digital model, each layer being formed by exposing a powder of an aluminum alloy to a beam of light or to a beam of charged particles, so as to bring about a fusion of the powder, followed by solidification, the method being characterized in that:
• the aluminum alloy powder is maintained at a temperature greater than or equal to 25°C and less than 160°C or between 300 and 500° VS ;
• the method comprises an application, to the part, of a post-manufacturing heat treatment at a temperature of 300 to 400° C.;
• the post-manufacturing heat treatment is carried out by exposing the part to a temperature rise greater than 5°C per minute, so as to reduce the residual stresses in the part and to limit the formation of cracks;
• the method does not include solution heat treatment followed by quenching.
• the powder is preferably maintained at a temperature comprised from 25 to 150° C., and even more preferably from 80° C. to 130° C., according to a first variant.
• the temperature rise is preferably greater than 10° C. per minute or greater than 20° C. per minute or greater than 40° C. per minute or greater than 100° C. per minute.
• the temperature rise can be instantaneous.
• Another object of the invention is an aluminum alloy part formed using a method according to the first object of the invention.
• FIG. 1 is a diagram illustrating an additive manufacturing process of the LPBF type.
• Figure 2 shows an image of an aluminum alloy part fabricated by an LPBF fabrication process with a crack at an acute angle.
• Fig. 3 illustrates the shape of specimens fabricated by an LPBF fabrication process.
• FIG. 1 schematizes the operation of an additive manufacturing process of the laser powder bed fusion (LPBF) type.
• the filler metal 15 is in the form of an aluminum alloy 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 filler material 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 numerical model.
• the plane is for example perpendicular to the axis of propagation Z.
• the interaction of the laser beam 12 with the powder 15 generates a selective fusion of the latter, followed by a solidification, resulting in the formation of a layer 20i.. .20 n .
• a layer is covered with powder of the filler metal and another layer is formed, superimposed on the previously produced layer.
• the thickness of the powder forming one or each layer can for example be between 10 and 250 ⁇ m.
• an increase in the layer thickness can be beneficial in order to limit the sensitivity to cracking of the alloy during the manufacture of the part and/or during the post-manufacture heat treatment.
• An increase in the layer thickness is preferably accompanied by an adaptation of the laser power, of the vector deviation (distance between two successive laser passes) and/or of the scanning speed of the laser in order to ensure a complete fusion of each layer of powder in optimal conditions.
• the thickness of each layer can be, for example, from 10 to 250 ⁇ m, preferably from 30 to 250 ⁇ m, preferably from 50 to 200 ⁇ m, preferably from 60 to 180 ⁇ m, preferably from 80 to 180 ⁇ m, from preferably 90 to 170 ⁇ m, preferably 100 to 160 ⁇ m.
• the support 10 forms a plate, on which layers of powder are successively deposited.
• the support comprises a heating means, allowing preheating of the powder prior to exposure to the laser beam 12, at a preheating temperature T determined beforehand.
• the heating means also makes it possible to maintain the layers produced at the temperature T.
• the heating means can comprise resistors or induction heating, or by another method of heating the powder bed: elements heaters around the powder bed or above the powder bed.
• the heating elements can be heating lamps, or a laser.
• the sphericity of a powder can for example be determined using a morphogranulometer
• the flowability of a powder can for example be determined according to the ASTM B213 standard or the ISO 4490:2018 standard. According to the ISO 4490:2018 standard, the flow time is preferably less than 50 seconds;
• the porosity preferably 0 to 5%, more preferably 0 to 2%, even more preferably 0 to 1% by volume.
• the porosity can in particular be determined by electronic scanning microscopy or by helium pycnometry (see standard ASTM B923);
• the powder can be obtained for example by atomization by gas jet, plasma atomization, atomization by water jet, atomization by ultrasound, atomization by centrifugation, electrolysis and spheroidization, or grinding and spheroidization.
• the powder according to the present invention is obtained by gas jet atomization.
• the gas jet atomization process begins with the pouring of molten metal through a nozzle.
• the molten metal is then hit by jets of neutral gases, such as nitrogen or argon, possibly accompanied by other gases, and atomized into very small droplets which cool and solidify as they fall inside. of an atomization tower.
• the powders are then collected in a can.
• the gas jet atomization process has the advantage of producing a powder having a spherical shape, unlike water jet atomization which produces a powder having an irregular shape.
• Another advantage of gas jet atomization is a good powder density, in particular thanks to the spherical shape and the particle size distribution. Yet another advantage of this method is a good reproducibility of the particle size distribution.
• the powder according to the present invention can be steamed, in particular in order to reduce its humidity.
• the powder can also be packaged and stored between its manufacture and its use.
• FIG. 2 shows for example the appearance of a crack on a part formed from an aluminum alloy comprising Zr according to a mass fraction of the order of 1%.
• the crack is surrounded by a circle in the figure.
• the aluminum part had been manufactured by LPBF, the powder having been preheated to 200°C, the manufacture having been followed by a post-manufacturing heat treatment at a temperature of 300°C for two hours. The crack appeared following the post-fabrication heat treatment.
• the inventors estimate that the crack is probably linked to the preheating temperature of the powder, which is not optimal.
• the temperature of the powder bed is generally between 150°C and 200°C.
• the layers formed by the additive manufacturing process can be subjected to such a temperature range for a long period of time, possibly exceeding several hours. These conditions are considered to promote cracking.
• the inventors consider that it is necessary to avoid preheating the powder to temperatures ranging from 160° C. to 290° C.
• the preheating of the powder bed can be carried out at a temperature lower than or equal to 140°C, or, better still, lower than or equal to 130°C.
• the preheat temperature is higher than the ambient temperature.
• the preferred preheating temperature ranges T of the powder bed are: 25°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.
• the use of a post-manufacturing heat treatment makes it possible to create relaxation conditions making it possible to eliminate the residual stresses as well as a precipitation of hardening phases. Also referred to as thermal expansion.
• the inventors have observed that it is preferable for the setpoint temperature T' of the post-manufacture heat treatment to be between 300° C. and 500° C., the duration of the post-manufacture heat treatment being adapted to the temperature used and the volume of the part: in general, the duration of the heat treatment post-fabrication is between 10 minutes and 50 hours.
• a post-fabrication heat treatment temperature T′ of 300° C. to 400° C. is preferred.
• the duration of the post-manufacture heat treatment is preferably between 30 minutes and 10 hours.
• the rise in temperature, initiating the post-manufacturing heat treatment is preferably as fast as possible.
• the rate of rise in temperature DT' (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, and more preferably greater than 20°C per minute and more preferably greater than 40°C per minute, and more preferably greater than 100°C per minute.
• temperature rise is meant the rise in temperature to which the part is subjected during the post-manufacturing heat treatment. It seems optimal for the rise in temperature to be instantaneous, that is to say for the manufactured part to be subjected, from the start of the post-manufacturing heat treatment, to the setpoint 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 setpoint temperature T′, or by rapid heating means of the fluidized bed or molten salt bath type. The rise in temperature can also be ensured by induction heating.
• the temperature variation inside the part depends in particular on the heating medium (liquid or air or inert gas) as well as on the shape of the part.
• the temperature in the thickness or at the surface of the part may be different. This is the reason why the rise in temperature mentioned above corresponds to the temperature outside the room.
• the preheating temperature corresponds to the conditions under which effective expansion can be obtained.
• the temperature range T can then be comprised from 300°C to 500°C. It is considered that at this temperature range, the manufacturing conditions of the part generate fewer residual stresses.
• a post-manufacture expansion heat treatment as previously described is also relevant.
• the post-manufacturing heat treatment can be replaced or supplemented by hot isostatic pressing, at a temperature between 300°C and 500°C.
• the CIC treatment can in particular make it possible to further improve the elongation properties and the fatigue properties.
• Hot isostatic pressing can be performed before, after, or instead of post-manufacturing heat treatment.
• the CIC treatment can be carried out at a pressure of 500 to 3000 bars and for a duration of 0.5 to 10 hours.
• the metal forming the powder 15 is an aluminum alloy comprising at least the following alloying elements:
• These elements can make it possible to increase the mechanical resistance of the alloy by solid solution and/or by formation of dispersoids which can appear during the manufacture of the part and/or during post-manufacture heat treatments.
• the elements, Zr, Sc, HF and Ti can also make it possible to control the granular structure during laser melting by promoting the appearance of equiaxed grains.
• Mg optionally Mg, according to a mass fraction of less than 0.30%, preferably less than 0.10%, more preferably less than 0.05%;
• This element can make it possible to increase the mechanical resistance of the alloy by solid solution. However, it can be sensitive to evaporation during laser melting, which can lead to the formation of fumes and instabilities of the melted zones. For these reasons, the addition of this element should be limited and preferably avoided. - optionally Zn, according to a mass fraction of less than 0.30%, preferably less than 0.10%, more preferably less than 0.05%;
• This element can make it possible to increase the mechanical resistance of the alloy by solid solution. However, it can be sensitive to evaporation during laser melting, which can lead to the formation of fumes and instabilities of the melted zones. For these reasons, the addition of this element should be limited and preferably avoided.
• These elements can make it possible to increase the mechanical resistance of the alloy by solid solution and/or by formation of dispersoids which can appear during the manufacture of the part and/or during post-manufacture heat treatments.
• W, Nb, Ta, Y, Nd, Ce, Co, Mo and/or mischmetal optionally at least one element chosen from: W, Nb, Ta, Y, Nd, Ce, Co, Mo and/or mischmetal, according to a mass fraction less than or equal to 5.00%, preferably less than or equal to 3 % each, and less than or equal to 15.00%, preferably less than or equal to 12%, more preferably less than or equal to 5% in total;
• - optionally at least one element chosen from: Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and/or Sn, according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.5%, preferably less than or equal to 0.3%, more preferably less than or equal to 0.1%, even more preferably less than or equal to 700 ppm each, and less than or equal to 2.00%, of preferably less than or equal to 1% in total;
• - optionally Fe according to a mass fraction of 0.50 to 7.00%, preferably from 1.00 to 6.00% according to a first variant, or according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.5%, preferably less than or equal to 0.3%, more preferably less than or equal to 0.1%, even more preferably less than or equal to 700 ppm according to a second variant;
• This element can make it possible to increase the mechanical resistance of the alloy by solid solution and/or by formation of dispersoids which can form during the manufacture of the part and/or during post-manufacture heat treatments.
• the Li can make it possible to increase the mechanical resistance of the alloy by solid solution. However, it can be sensitive to evaporation during laser melting, which can lead to the formation of fumes and instabilities of the melted zones. For these reasons, the addition of this element should be limited, preferably avoided.
• the Ag can make it possible to increase the mechanical resistance of the alloy by solid solution and to facilitate the germination of other hardening precipitates, such as precipitates of the Al2Cu type for example.
• other hardening precipitates such as precipitates of the Al2Cu type for example.
• impurities according to a mass fraction of less than 0.05% each (ie 500 ppm) and less than 0.15% in total;
• the metal 15 forming the powder is an aluminum alloy comprising at least the following alloying elements:
• - Zr and at least one element chosen from: Ti, V, Sc, Hf, Er, Tm, Yb and Lu, according to a mass fraction greater than or equal to 0.30%, preferably 0.30-2.5%, 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%, even more preferably 0.80-1.20% in total, knowing that Zr represents from 10 to less than 100% of the ranges of percentages given above;
• Mg optionally Mg, according to a mass fraction of less than 0.30%, preferably less than 0.10%, more preferably less than 0.05%;
• Ni, Mn, Cr and/or Cu optionally at least one element chosen from: Ni, Mn, Cr and/or Cu, according to a mass fraction of 0.50 to 7.00%, preferably 1.00 to 6.00% each; preferably, according to a mass fraction of less than 25.00%, preferably less than 20.00%, more preferably less than 15.00% in total;
• W, Nb, Ta, Y, Nd, Ce, Co, Mo and/or mischmetal optionally at least one element chosen from: W, Nb, Ta, Y, Nd, Ce, Co, Mo and/or mischmetal, according to a mass fraction less than or equal to 5.00%, preferably less than or equal to 3 % each, and less than or equal to 15.00%, preferably less than or equal to 12%, more preferably less than or equal to 5% in total;
• - optionally at least one element chosen from: Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and/or Sn, according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.5%, preferably less than or equal to 0.3%, more preferably less than or equal to 0.1%, even more preferably less than or equal to 700 ppm each, and less than or equal to 2.00%, of preferably less than or equal to 1% in total;
• - optionally Fe according to a mass fraction of 0.50 to 7.00%, preferably from 1.00 to 6.00% according to a first variant, or according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.5%, preferably less than or equal to 0.3%, more preferably less than or equal to 0.1%, even more preferably less than or equal to 700 ppm according to a second variant;
• the metal forming the powder 15 is an aluminum alloy comprising at least the following alloying elements:
• - Zr according to a mass fraction greater than or equal to 0.30%, preferably 0.30-2.50%, 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%, even more preferably 0.80-1.20;
• Mg optionally Mg, according to a mass fraction of less than 0.30%, preferably less than 0.10%, more preferably less than 0.05%;
• Ni, Mn, Cr and/or Cu optionally at least one element chosen from: Ni, Mn, Cr and/or Cu, according to a mass fraction of 0.50 to 7.00%, preferably 1.00 to 6.00% each; preferably, according to a mass fraction of less than 25.00%, preferably less than 20.00%, more preferably less than 15.00% in total;
• Hf Hf
• Ti Er, W, Nb, Ta, Y, Yb, Nd, Ce, Co, Mo, Lu, Tm, V and/or mischmetal, according to a lower mass fraction or equal to 5.00%, preferably less than or equal to 3% each, and less than or equal to 15.00%, preferably less than or equal to 12%, more preferably less than or equal to 5% in total;
• - optionally at least one element chosen from: Si, La, Sr, Ba, Sb, Bi, Ca, P, B, In and/or Sn, according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.5%, preferably less than or equal to 0.3%, more preferably less than or equal to 0.1%, even more preferably less than or equal to 700 ppm each, and less than or equal to 2.00%, of preferably less than or equal to 1% in total;
• - optionally Fe according to a mass fraction of 0.50 to 7.00%, preferably from 1.00 to 6.00% according to a first variant, or according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.5%, preferably less than or equal to 0.3%, more preferably less than or equal to 0.1%, even more preferably less than or equal to 700 ppm according to a second variant;
• the alloy according to the present invention comprises a mass fraction of at least 80%, more preferentially of at least 85% of aluminium.
• the melting of the powder can be partial or total. Preferably 50 to 100% of the exposed powder melts, more preferably 80 to 100%.
• the aluminum alloy comprises:
• - Zr according to a mass fraction from 0.50 to 3.00%, preferably from 0.50 to 2.50%, preferably from 0.60 to 1.40%, more preferably from 0.70 to 1.30 %, even more preferably from 0.80 to 1.20%, even more preferably from 0.85 to 1.15%; even more preferably from 0.90 to 1.10%;
• - optionally Fe 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%; and preferably greater than or equal to 0.05, preferably greater than or equal to 0.10%;
• Si optionally Si, according to a mass fraction less than or equal to 1.00%, preferably less than or equal to 0.50%;
• the composition of mischmetal is generally around 45 to 50% cerium, 25% lanthanum, 15 to 20% neodymium and 5% praseodymium. According to one embodiment, the addition of La, Bi, Mg, Er, Yb, Y, Sc and/or Zn is avoided, the preferred mass fraction of each of these elements then being less than 0.05%, and preferably less than 0.01%.
• the addition of Fe and/or Si is avoided.
• these two elements are generally present in the alloys of common aluminum at contents as defined above.
• the contents as described above can therefore also correspond to contents of impurities for Fe and Si.
• the elements Ag and Li can act on the strength of the material by hardening precipitation or by their effect on the properties of the solid solution.
• the alloy can also comprise at least one element for refining the grains, for example AITiC or AITÎB2 (for example in AT5B or AT3B form), according to an amount less than or equal to 50 kg/tonne, preferably less than or equal to 20 kg/ton, even more preferably less than or equal to 12 kg/ton each, and less than or equal to 50 kg/ton, preferably less than or equal to 20 kg/ton in total.
• AITiC or AITÎB2 for example in AT5B or AT3B form
• a heating construction plate or heating by a laser, by induction, by heating lamps or by heating resistors which can be placed below and/or inside build plate, and/or around the powder bed.
• this laser is preferably defocused, and can be either co-axial with the main laser which is used for melting the powder, or separated from the main laser.
• the method can be a construction method with a high deposition rate.
• the deposition rate may for example be greater than 4 mm 3 /s, preferably greater than 6 mm 3 /s, more preferably greater than 7 mm 3 /s.
• the deposition rate is calculated as the product between the scanning speed (in mm/s), the vector deviation (in mm) and the layer thickness (in mm).
• the method can use a laser, and optionally several lasers.
• suitable for structural hardening alloys solution treatment followed by quenching and tempering of the formed part and/or hot isostatic pressing can be carried out.
• Hot isostatic pressing can in this case advantageously replace solution treatment.
• the method according to the invention is advantageous because it preferably does not require any solution treatment followed by quenching. Dissolution can have a detrimental effect on the mechanical resistance in certain cases by participating in a coarsening of the dispersoids or of the fine intermetallic phases.
• the quenching operation could lead to distortion of the parts, which would limit the primary advantage of using additive manufacturing, which is obtaining parts directly in their shape. final or near-final.
• the method according to the present invention also 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 the roughness and/or improve the resistance to corrosion and/or improve the resistance to the initiation of fatigue cracks.
• the alloy used was an aluminum alloy comprising: Mn: 4% - Ni: 2.85% - Cu: 1.93% - Zr: 0.88%.
• the composition was determined by ICP-MS (induced Coupled Plasma Mass Spectrometry: mass spectrometry coupled to an inductive plasma).
• a powder was obtained by gas jet atomization (Argon). The particle size ranged essentially from 3 ⁇ m to 100 ⁇ m, with a D10 (10% fractile) of 27 ⁇ m, a D50 (median diameter) of 43 ⁇ m and a D90 (90% fractile) of 62 ⁇ m. From the powder, the specimens were formed using LPBF EOSM290 equipment (supplier EOS).
• the operating parameters were: laser power: 370 W - scanning speed: 1400 mm/s - vector deviation 0.11 mm - thickness of each layer: 60 ⁇ m - heating temperature of the plate (temperature preheat): 100°C.
• the specimens were placed on a plate 250 mm ⁇ 250 mm in size and 20 mm thick.
• the test specimens were kept integral with the plate, the latter having been cut into portions of section 30 mm ⁇ 30 mm, of thickness 20 mm, each portion of the plate being connected to a test specimen. Part of the specimens, attached to a portion of the plate, was subjected to stress relief by post-manufacturing heat treatment.
• Maintaining the specimens secured to the plate is a common practice of those skilled in the art, which, without being bound by theory, makes it possible not to relax the residual stresses induced by the process.
• LPBF fabrication before post-fabrication heat treatment If the specimens had been separated from the platen before the post-fabrication heat treatment, then there could have been a distortion of the specimens, in particular in the case of a complex geometry.
• the specimens were: - either placed in a hot oven, already brought to the expansion temperature: the rise in temperature is then considered to be instantaneous.
• Table 1 represents the results obtained on eight test specimens. [Table 1]
• the tests show that an instantaneous rise in temperature, obtained by placing the specimen in the furnace, already brought to the post-manufacturing heat treatment temperature, is optimal (absence of cracking) when the treatment temperature post-manufacturing temperature is greater than 300°C.
• the comparison of tests 8 (gradual rise in temperature up to 300° C.) and 5 (instantaneous rise to the temperature of 300° C.) shows that it is preferable for the rise in temperature to be rapid, even instantaneous. Thus, to avoid the appearance of cracking during expansion, it is preferable for the temperature rise to be as rapid as possible.
• SLS Selective Laser Sintering
• SHS Selective Heat Sintering
• EBM Electro Beam Melting
• DED Direct Energy Deposition
• DMD Direct Metal Deposition
• DLD Direct Laser Deposition
• LFMT - laser freeform manufacturing technology
• LMD Laser Metal Deposition
• CSC Cold Spray Consolidation

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• 2021
  • 2021-05-28 FR FR2105626A patent/FR3123235A1/fr active Pending
• 2022
  • 2022-05-24 WO PCT/FR2022/050981 patent/WO2022208037A1/fr active Application Filing
  • 2022-05-24 KR KR1020237045059A patent/KR20240014505A/ko unknown
  • 2022-05-24 JP JP2023573046A patent/JP2024521805A/ja active Pending
  • 2022-05-24 DE DE22733191.5T patent/DE22733191T1/de active Pending
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