Additive manufacturing method for manufacturing a metal part comprising inclusions of at least one phosphor compound

Abstract

The invention relates to a method for manufacturing a metal alloy part by additive manufacturing, said metal alloy comprising a metal element A and said part further comprising inclusions of a phosphor compound consisting of a metal oxide doped by said metal element A, said method comprising at least one step of forming a layer comprising said metal alloy comprising a metal element A and inclusions of said phosphor compound by an additive manufacturing technique selected from laser metal deposition and laser powder bed fusion, from a mixture comprising a metal alloy powder comprising the metal element A and a precursor powder of said phosphor compound, said precursor powder consisting of a powder of said metal oxide optionally doped with a metal element B different from said metal element A, said phosphor compound being formed in situ, during the implementation of the additive manufacturing technique, by atomic diffusion of a portion of the metal element A of the metal alloy to the metal oxide and exchange of said metal element A with a metal element of the metal oxide.

Description

[0001]40437DEL-P 1 Method for manufacturing by additive manufacturing a metal part comprising inclusions of at least one luminophoric compound Description 5 TECHNICAL FIELD The present invention relates to a method for manufacturing by additive manufacturing a metal alloy part, such as a steel part, comprising at least one luminophoric compound. The present invention naturally finds its10 application in all types of industries wishing to design metal parts having optical properties by incorporating luminophoric compound(s) into said parts. Conventionally, metal alloy parts comprising additives are prepared by a step of mechanical and very energetic co-grinding (for example,15 via a ball mill or an attritor) of a powder of a metal alloy intended to be part of the composition of the part and a powder of the luminophoric compound,said co-grinding step being followed by a step of sintering the mixture of powders to form the desired metal part. The manufacture of metal alloy parts by this route does not make it easy to obtain parts with overly complex shapes, due to the difficulty of obtaining suitable molds for this type of shape. Thus, in view of what already exists, the authors of the present invention have proposed to develop a method for manufacturing a metal alloy part using a specific additive manufacturing technique and the advantages resulting therefrom, such as the operating conditions to allow the formation of the luminophoric compound(s) included in said part and a greater variety of shapes that can be achieved, which thus makes it possible to broaden the scope of application in all fields requiring the use of metal parts with luminophoric properties. 40437DEL-P 2 DISCLOSURE OF THE INVENTION Thus,the invention relates to a method for manufacturing a metal alloy part by additive manufacturing, said metal alloy comprising a metal element A and said part further comprising inclusions of a luminophor compound consisting of a metal oxide doped with said metal element A, said method comprising at least one step of forming a layer comprising said metal alloy comprising a metal element A and inclusions of said luminophor compound by an additive manufacturing technique chosen from laser melting of projected powder and laser melting on a powder bed, from a mixture comprising a metal alloy powder comprising the metal element A and a precursor powder of said luminophor compound, said precursor powder consisting of a powder of said metal oxide optionally doped with a metal element B different from said metal element A, said luminophor compound being formed in situ,when implementing the additive manufacturing technique, by atomic diffusion of a portion of the metallic element A of the metallic alloy to the metallic oxide and exchange of said metallic element A with a metallic element of the metallic oxide. The metallic alloy of the metallic alloy powder may be chosen from iron alloys, aluminum alloys, titanium alloys, nickel alloys, copper alloys and steels. The metallic element A present in the metallic alloy powder may be chosen from In, Sn, Pb, Sb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Pd, Ag, Ir, Pt and Au. In an advantageous variant, this metallic element A is chosen from Cr, Ce, Fe and Mn. In a preferred variant, this metallic element A is Cr. In a particular embodiment, the steels are stainless steels, that is to say steels comprising, as metallic element A,chromium. More specifically, the metal alloy may be steel comprising, in addition to chromium, one or more elements selected from manganese, phosphorus, sulfur, silicon, nickel, molybdenum, cobalt and mixtures thereof. 40437DEL-P 3 More particularly, the metal alloy of the metal part may be austenitic steel, for example, an austenitic steel of grade 1.4404, 304L or 316L. The luminophor compound consisting of a metal oxide doped with said metal element A may be a metal oxide doped with chromium (in which case the metal element A corresponds to chromium), it being understood that this metal oxide thus doped must have luminophor properties, that is to say an ability to emit light after excitation. The metal oxide of the precursor powder of the phosphor compound10 may be an oxide of one or more metals chosen from Li, K, Mg, Ca, Sr, Ba, Sc, Y, La, Lu, Ti, Zr, Hf, V, Nb, Ta, Zn,Cd, B, Al, Ga, Si and Ge. This metal oxide may be a simple metal oxide and be advantageously chosen from Li2O, K2O, MgO, CaO, SrO, BaO, Sc2O3, Y2O3, La2O3, Lu2O3, TiO2, ZrO2, HfO2, V2O5, Nb2O5, Ta2O5, ZnO, CdO, B2O3, Al2O3, Ga2O3, SiO2 and GeO2. 15 This metal oxide may also be a mixed metal oxide and be advantageously chosen from Y3Al5O, 12 , YAlO3, Y4Al2O9, Sr4Al2O7, Sr3Al2O6, SrAl2O4, SrAl4O7, Sr4Al 12 O 19 , SrAl 12 O 19 , LiAlO2, LaAlO3, MgGa2O4, CaAl2O 4, ZnAl2O 4, CaGa2O 4, CaGa4O, BaAl2O4, CaAl4O7, LiAl5O8, KAI 11 O 17 , KGa 11 O 17 , BaMgAl 10 O 17 and that 0.5 Ba 0.5 Al 12 O 19. This mixed metal oxide can more particularly be chosen from among garnets, spinels and perovskites. When this mixed metal oxide is a garnet, it has the general chemical formula X3Z5O 12 and can notably be Y3Al5O 12 . When this mixed metal oxide is a spinel, it has the general chemical formula XZ2O4 and can in particular be SrAl2O4, BaAl2O4, MgGa2O4, CaAl2O4, CaGa2O4 or ZnAl2O4. When this mixed metal oxide is a perovskite, it has the general chemical formula XZO3 and can in particular be YAlO3 or LaAlO3. In a preferred variant, the mixed metal oxide of the precursor powder of the luminophore compound is chosen from Y3Al5O 12 , BaAl2O4, SrAl2O4 and YAlO3. 40437DEL-P 4 In an even more preferred variant, this mixed metal oxide of the precursor powder of the luminophor compound is the garnet-type oxide corresponding to the formula Y3Al5O 12. As indicated above, the metal oxide of the precursor powder of the 5 phosphor compound may optionally be doped with a metallic element B, it being specified that this metallic element B is then different from the metallic element A present in the metallic alloy powder. This metallic element B may in particular be chosen from In, Sn, Pb, Sb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Pd, Ag, Ir, Pt and Au. In an advantageous variant, this metallic element B is chosen from Cr, Ce, Fe and Mn. In particular, when the metallic element A is not Cr, the metallic element B is advantageously Cr. 15 In a preferred variant, and in particular (but not only) when the metallic element A is Cr, the metallic element B is Ce. Examples of luminophore compounds that can be formed in situ when implementing the additive manufacturing technique include: Y3Al5O 12:Ce 3+ , YAlO3:Ce 3+ , Y3Al5O 12 : Me 3+ , YAlO3:Eu 3+ , Y4Al2O9:Eu 3+ , YAlO3:Sm 3+ ,20 YAlO3:Tb 3+ , Al2O3:Cr 3+ , Y2O3:Eu 3+ , LiAlO2:Fe 3+ , LiAlO2:Mn 2+ , LaAlO3:Eu 3+ , LaAlO3:Sm 3+ , MgAl2O4:Mn 2+ , MgGa2O4:Mn 2+ , CaAl2O4:Mn 2+ , CaAl2O4:Eu 2+ , ZnAl2O4:Mn 2+ , ZnGa2O4:Mn 2+ , CaGa2O4:Mn 2+ , CaGa4O:Mn 2+ , SrAl2O4:Eu 2+ , BaAl2O4:Eu 2+ , CaAl4O7:Pb 2+ Mr 2+ , LiAl5O8:Fe 3+ , LiAl5O8:Mn 2+ , FOOD 11 O 17 : Tea + , KGa 11 O 17 :Mr 2+ , BaMgAl 10 O 17 :Ce 3+ , BaMgAl 10 O 17 : Me 2+ , BaMgAl 10 O 17 : Me 2+ Mr 2+ , ca 0.5 Ba 0.5 Al 12 O 19 :Ce 3+ Mr2+ , SrAl 12 O 19 :Eu 2+ ,Mn 2+ , SrGa 12 O 19 :Mn 2+ ,25 SrAl 12 O 19 :This 3+ ,Mn 2+ and Y3Al5O 12 :This 3+ ,Cr 3+ The luminophor compound can thus be a garnet-type oxide corresponding to the formula Y3Al5O 12 (also known by the acronym YAG) doped with chromium (called YAG: Cr 3+ ), which means in other words that part of the aluminum in the YAG is substituted by chromium, said oxide being able to be doped, in addition, by another30 metallic element B, such as cerium. Thus, more specifically, the compound 40437DEL-P 5 phosphor can be a garnet-type oxide corresponding to the formula Y3Al5O 12 doped with cerium and chromium (called Y3Al5O 12 :This 3+ ,Cr 3+), cerium being substituted on the dodecahedral sites of yttrium and chromium being substituted on the octahedral sites of aluminum. The YAG compound doped, at the same time, by chromium Cr 3+ and 5 cerium Ce 3+ exhibits luminescence in both the red (i.e. between 650 nm and 750 nm) due to in situ doping of Cr 3+ and a luminescence in the green / yellow (between 500 nm and 575 nm) due to Ce 3+initially present in the YAG crystal. Alternatively, the phosphor compound may be a spinel-type oxide doped with chromium. 10 Furthermore, the method may comprise at least one step of forming a layer consisting of said metal alloy comprising a metal element A by an additive manufacturing technique chosen from laser melting of projected powder and laser melting on a powder bed from a powder consisting of a metal alloy powder comprising the metal element A.15 Thus, the method covers the manufacture of the following parts: - a part in which each layer formed by the method is a layer comprising said metal alloy comprising a metal element A and inclusions of said luminophoric compound, in which case the formation step mentioned just above will not be implemented; 20 - in the opposite case, that is to say, in the case where the formation step mentioned just above will be implemented one or more times, a part in which at least one of the layers formed by the method is a layer comprising said metal alloy comprising a metal element A and inclusions of said luminophoric compound and at least one of the layers formed by the method is a layer consisting of said metal alloy comprising a metal element A and this independently of the way in which these layers are arranged relative to each other.Whether for one or other of the aforementioned formation steps, these are implemented by a specific additive manufacturing technique chosen from laser powder fusion and laser powder bed fusion.40437DEL-P 6 In particular, according to a first embodiment, each step of forming a layer comprising said metal alloy comprising a metal element A and inclusions of said luminophor compound and, where appropriate, each step of a layer consisting of said metal alloy comprising a metal element A 5 can be implemented by a laser melting process of projected powder, also known under the following names: direct laser manufacturing process or even more precisely, direct manufacturing process by laser melting of projected powder or LMD process (corresponding to the English terminology “Laser Metal Deposition”) or DED process (corresponding to the English terminology “Directed Energy Deposition”).Generally speaking, the laser melting process of projected powder is based on the combined use of a power laser and a powder distribution device (conventionally, a nozzle) that is coaxial or has a lateral injection. From a concrete point of view, for each layer to be deposited, the powder or the mixture of powders, transported by a vector gas (for example, argon, helium, nitrogen) is melted, in whole or in part, in contact with the laser beam, the melting being able to be completed in contact with the liquid metal bath formed on the substrate (or manufacturing plate) resulting from the laser-material interaction, before solidification of the whole (molten powder + liquid metal bath resulting from the melting of the lower layers). The movement of the laser, the powder distribution device and the substrate are controlled20 in relation to a digital model defined in the formation of the part to be obtained.The laser melting process of projected powder depends on several parameters and, in particular, the characteristics of the powder or the mixture of powders, the nature and power of the laser, the laser scanning speed, the powder flow rate, the desired layer thickness, the distance between each manufacturing bead. 25 The person skilled in the art will determine, if necessary, by prior tests, these different parameters, depending on the metal part that he wishes to obtain.In particular, when the phosphor compound is a cerium- and chromium-doped YAG-type compound and the sprayed powder mixture comprises a 316L steel powder and a cerium-doped YAG powder, the parameters of the step(s) 40437DEL-P 7 of forming the layer comprising 316L steel and cerium- and chromium-doped YAG inclusions may be as follows: -for an OPTOMEC machine, a ytterbium-doped fiber laser, a wavelength of 1064 nm and a laser spot of 1.2 mm for a fixed working distance of 5 to 12 mm; -a laser power ranging from 300 W to 1000 W; -a scanning speed ranging from 1 mm / s to 100 mm / s; - a powder flow rate ranging from 0.5 rpm to 20 rpm (rpm corresponding to the rotation speed of the powder distribution motor); 10 - an inter-cord distance ranging from 0.1 mm to 2 mm and a layer thickness of 0.1 mm to 2 mm.More specifically, when the luminophor compound is a YAG type compound doped with cerium and chromium and the precursor powder of said compound is a powder of a YAG type compound doped with cerium, the laser fluence, during the formation step, advantageously ranges from 265 W / mm. 2 at 900 W / mm 2. In particular, when the projected powder is a 316L steel powder, the parameters of the step(s) of forming the layer made of 316L steel are as follows: -a spherical powder morphology and advantageously having a particle size ranging from 45 µm to 106 µm; -for an OPTOMEC machine, a ytterbium-doped fiber laser, a wavelength of 1064 nm and a laser spot of 1.2 mm for a working distance of 12 mm between the laser projection nozzle and the substrate; -a laser power ranging from 100 W to 1500 W; -a scanning speed ranging from 1 mm / s to 100 mm / s; -a powder flow rate ranging from 0.5 rpm to 20 rpm (rpm corresponding to the rotation speed of the powder distribution motor); - an inter-cord distance ranging from 0.1 mm to 2 mm and a layer thickness of 0.1 mm to 2 mm.40437DEL-P 8 For each step of forming a layer comprising said metal alloy comprising a metal element A and inclusions of said phosphor compound, the metal alloy powder and the precursor powder of said phosphor compound may be dispensed via a single powder dispenser (in which case, the two powders form a mixture in the dispenser) or may be dispensed simultaneously via two separate powder dispensers. In the case where the metal alloy powder and the precursor powder of said phosphor compound are dispensed simultaneously via two separate powder dispensers (it being understood that both types of powders must have good flowability), the metal alloy powder and the precursor powder of said phosphor compound will advantageously have a spherical morphology with a particle size ranging from 45 µm to 106 µm.With the use of two separate powder dispensers, there is a possibility to independently adjust the flow rate of metal alloy powder and the flow rate of precursor powder according to the desired percentage15 of phosphor compound insertions. For example, to achieve a phosphor compound incorporation of 6.25% during the fabrication of the relevant layer, the flow rate of metal alloy powder can be set at 3.75 rpm and the flow rate of precursor powder can be set at 0.75 rpm.According to a second embodiment, each step of forming a layer comprising said metal alloy comprising a metal element A and inclusions of said luminophor compound and, where appropriate, each step of forming a layer consisting of said metal alloy comprising a metal element A can be implemented by a laser powder bed fusion process, also known as the LPBF (corresponding to the English terminology “Laser Powder Bed Fusion”) or SLM (corresponding to the English terminology “Selective Laser Melting”) or LBM (corresponding to the English terminology “Laser Beam Melting”) process.Generally speaking, the LPBF process consists of spreading powder on a manufacturing plate and then passing a laser over the powder thus spread to melt said powder, the molten material then solidifying by cooling, this sequence of steps being repeated as many times as necessary 40437DEL-P 9 until the desired part is obtained. The trajectory of the laser is defined by a digital file (CAD file then slicer which will cut the part into layers). The laser powder bed fusion process depends on several parameters and, in particular, the characteristics of the powder, the nature and power 5 of the laser, the laser scanning speed, the layer thickness and the distance between each manufacturing bead. The person skilled in the art will determine, if necessary, by preliminary tests, these different parameters, depending on the metal part he wishes to obtain.In particular, when the phosphor compound is a compound of the 10 YAG type doped with cerium and chromium and the mixture comprises a 316L steel powder and a YAG powder doped with cerium, the parameters of the step(s) for forming the layer comprising 316L steel and inclusions of YAG doped with cerium and chromium may be as follows: - for a TruPrint 1000 machine, a fiber laser doped with ytterbium, a wavelength of 1064 nm and a laser spot of 55 µm; - a laser power ranging from 20 W to 200 W; - a scanning speed ranging from 10 mm / s to 1300 mm / s; - a layer thickness ranging from 10 µm to 100 µm; - an inter-bead distance ranging from 10 µm to 150 µm. 20 More specifically, when the luminophor compound is a YAG type compound doped with cerium and chromium and the precursor powder of said compound is a powder of a YAG type compound doped with cerium, the laser fluence, during each formation step, advantageously ranges from 8400 W / mm.2 at 84000W / mm 2. In particular, when the powder is a 316L steel powder, the parameters of the step(s) for forming the layer made of 316L steel are as follows: - for a TruPrint 1000 machine, a ytterbium-doped fiber laser, a wavelength of 1064 nm and a laser spot of 55 µm; - a laser power ranging from 20 W to 500 W; - a scanning speed ranging from 10 mm / s to 3000 mm / s; 40437DEL-P 10 - a layer thickness ranging from 10 µm to 100 µm; - an inter-bead distance ranging from 10 µm to 150 µm. Powders for the LPBF process must advantageously have a spherical morphology and a particle size ranging from 15 µm to 45 µm.5 Whether for the projected powder laser fusion technique or the powder bed laser fusion technique, the authors of the present invention were able to demonstrate the in situ formation of the luminophoric compound concomitantly with the implementation of the chosen technique, the energy used during this implementation allowing the atomic diffusion of said metallic element A in the metallic oxide and the exchange10 of said metallic element A with a metallic element of the metallic oxide, this process being able to be demonstrated by laser spectroscopy tests and by analyzing the luminescent emission bands of the luminophoric compound obtained. When the luminophoric compound is a garnet-type compound of formula Y3Al5O. 12 doped with chromium and cerium, the precursor powder of said phosphor compound15 may be a garnet-type compound powder of formula Y3Al5O 12doped with cerium. Before implementing the aforementioned formation steps and when the technique implemented is the LPBF technique or, failing that, when the technique implemented is the projected powder laser fusion technique and one of the powders20 does not have good flowability, the method may comprise a step of preliminary preparation of the mixture comprising the powder of said metal alloy and a precursor powder of said phosphor compound. This preliminary mixing step is advantageously suitable when at least one of the powders does not have a morphology suitable for good flowability (for example, a powder having a spherical morphology with a particle size ranging from 45 µm to 106 µm in the case where the technique chosen is projected powder laser fusion).This preparation step may consist of bringing said metal alloy powder and said precursor powder into contact and subjecting the resulting mixture to any mixing techniques that make it possible in particular to improve its flowability. In particular, the contacting may be carried out in a rotary mixer or in a container subjected to stirring by attachment to a stirrer. In the latter case, deagglomeration objects, such as beads, may be added to the container. In particular, these deagglomeration objects, such as beads, have sufficient strength and do not cause pollution of the powder mixture. They may be, in particular, ceramic beads or metal beads and, more specifically, steel beads. The beads may have a diameter ranging from 5 mm to 15 mm, preferably from 3 mm to 7 mm and, even more specifically, beads having a diameter of approximately 5 mm.The volume ratio between the deagglomeration objects, such as beads, and the powders (atomized powder + oxide powder(s)) can range from 0.5 to 3. The tank, in which the powders and the powder deagglomeration objects are placed, can be a tank made of plastic or metal material, it being understood that the material must be sufficiently strong to withstand the shocks induced by the mixing operation. The tank can be a tank having a volume ranging from 1 to 2 liters. The tank advantageously has a filling rate ranging from 30 to 70% (for example, equal to 40%), this filling rate corresponding to the % of total volume of the tank occupied by the powders and the powder deagglomeration objects. The tank is attached to an agitator which will impart an agitating movement to the tank, this agitator being able to be in particular a three-dimensional agitator, such as those marketed under the Turbula® brand.In such a stirrer, the reservoir is subjected to a three-dimensional movement due to the action of the stirrer and the contents of the reservoir (namely, the powders and the powder deagglomeration objects) are thus subjected to a continuously changing pulsed movement. 40437DEL-P 12 Finally, regardless of the additive manufacturing technique chosen, the layer formation steps are repeated as many times as possible until the desired part with a chosen thickness and shape is obtained. Other advantages and characteristics of the invention will appear in the 5 non-limiting detailed description below. BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] represents a photograph of a section of the sample with insertion of the phosphor compound obtained according to Example 1, the dark particles corresponding to the luminescent particles, the enlarged views above the 10 photograph corresponding to the different spots for the laser spectroscopy tests. [Fig.2] is a graph illustrating the evolution of the intensity I (in arbitrary units u.) as a function of the wavelength λ (in nm), curve a) corresponding to spot 1 of the sample in Figure 1, curve b) to spot 2 of the sample in Figure 1, curve c) to spot 3 of the sample in Figure 1 and curve d) to spot 4 of the sample15 in Figure 1. [Fig. 3] represents a photograph of a section of the sample with insertion of the phosphor compound obtained according to Example 2. [Fig. 4] represents a graph illustrating the evolution of the intensity I (in arbitrary units u.a) as a function of the wavelength λ (in nm), curve a)20 corresponding to spot 2 of the sample of figure 3, curve b) to spot 4 of the sample of figure 3, curve c) to spot 5 of the sample of figure 3, curve d) to spot 6 of the sample of figure 3, curve e) to spot 7 of the sample of figure 3, curve f) to spot 9 of the sample of figure 3, curve g) to spot 10 of the sample of figure 3, curve h) to spot 15 of the sample of figure 3, curve i) to spot 1825 of the sample of figure 3 and curve j) to spot 20 of the sample of figure 3. DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS EXAMPLE 1 40437DEL-P 13 This example illustrates the implementation of the method in accordance with the invention for the manufacture by LMD of a part in austenitic steel of grade 316L comprising inclusions of a luminophor compound of the YAG type doped with cerium and chromium.Before manufacturing the part as such, a mixture of powders is prepared in advance, comprising the powder consisting exclusively of 316L austenitic steel and a precursor powder of the luminophor compound, this precursor powder being consisting exclusively of a YAG type compound doped with cerium Ce. 3+ To do this, the 316L austenitic steel powder has a particle size ranging from 45 µm to 106 µm, an apparent density of 4.02 g / cm 3 , a typed density of 4.77 g / cm 310 and a flowability of 17.70 s / 50 g (determined with a Hall cone) and the precursor powder of the phosphor compound has a particle size ranging from 6.6 µm to 37.3 µm at a rate of 5% by mass relative to the total mass of the mixture are mixed by mechanosynthesis for 15 hours at a rotation speed of 400 rpm. Then, in a first step, 8 layers are deposited from15 a powder consisting exclusively of 316L austenitic steel, each layer being deposited using an OPTOMEC laser projection machine with a fibered and ytterbium-doped infrared laser having a wavelength of 1064 nm and a spot of 1.2 mm, the other parameters used being the following: -Working distance: 12 mm; 20 -Laser power: 450W; -Scanning speed: 5 mm / s; -Powder flow rate: 2 rpm; -Inter-bead distance: 0.84 mm and layer thickness: 0.5 mm.In a second step, the mixture thus obtained is also deposited25 by LMD on the layers previously deposited by LMD, in the form of two layers, according to a laser creep of 398 W / mm. 2 (laser power delivered per cm 2), whereby the luminophoric compound is inserted on the last manufacturing layers of the metallic compound, as illustrated in Figure 1 representing a photograph of a section of the sample with insertion of the luminophoric compound, the dark particles corresponding30 to the luminescent particles. 40437DEL-P 14 Laser spectroscopy tests for an excitation wavelength of 405 nm were carried out according to different spots (indicated in Figure 1, spot 1, spot 2, spot 3 and spot 4), the results being reported in Figure 2, illustrating the evolution of the intensity I (in arbitrary units au) as a function of the wavelength λ (in nm), curve 5 a) corresponding to spot 1 of the sample in Figure 1, curve b) to spot 2 of the sample in Figure 1, curve c) to spot 3 of the sample in Figure 1 and curve d) to spot 4 of the sample in Figure 1.It appears that, for the sample, the emission of cerium is still present, which is characterized by a broad emission band located between 500 and 575 nm but also a new band appears with peaks10 ranging from 650 nm to 750 nm corresponding to a new phase corresponding to Y3Al5O. 12 : Cr or in other words to the YAG compound doped with chromium. Since the simultaneous emission of Ce ions 3+ and Cr ions 3+is observed, this proves that the phosphor compound is a YAG compound doped with both cerium (what remains of the original doping) and chromium (which results from the in situ atomic diffusion of chromium from the metal alloy to the YAG compound during LMD deposition thanks to the high temperatures involved during this deposition). Without being bound by theory, the chromium present in the 316L steel diffuses towards the precursor compound YAG:Ce and takes the place of a part of the aluminum on the octahedral sites of the crystallographic structure of the YAG, the incorporation of chromium inducing emission peaks in the red region (i.e. between 650 nm and 750 nm). The phosphor compound particles have an average size of 200 µm, which corresponds to a size larger than the precursor powder size, which could be explained by a coalescence phenomenon during the melting of the powder followed by solidification.25 Alternatively, a metal part was prepared based on the same conditions as those mentioned above, except that the preparation of the mixture was obtained using a three-dimensional Turbula-type stirrer. To do this, the 316L steel powder (237.5 g) and the YAG:Ce powder (12.5 g) at a rate of 2% by mass relative to the total mass of the powder mixture are placed in the same plastic bottle (VWR brand, translucent PE-LD and 40437DEL-P 15 1L) in the presence of steel balls (1010 g) 5 mm in diameter, the filling rate of the bottle being 40%. The bottle is closed and then attached to a Turbula® brand agitator, the model being close to the Turbula® type T2F, with dimensions of 500*600*400 mm, a maximum container load ranging from 6 to 10 kg and a movement frequency ranging from 23 to 101 min. -1and the stirring is carried out for a period of 18 hours, the container being fixed to a nacelle by elastic bands and then three-dimensional pulsating movements are applied to it during this period. Once the mixing is complete, the contents of the bottle are recovered and the10 powder and the balls are separated using a simple sieve. The metal part thus obtained is also subjected to laser spectroscopy tests for an excitation wavelength of 405 nm, which also make it possible to detect the YAG phase doped with chromium, which demonstrates that the mixing technique for the preparation of the powder mixture has no influence on the obtaining15 of the luminophor compound. Furthermore, it appears that the chromium-doped YAG phase appears both with the powder mixture containing 2% YAG:Ce powder and with the powder mixture containing 5% YAG:Ce powder, which shows that the quantity of YAG:Ce powder in the mixture has no influence on obtaining this phase.EXAMPLE 2 20 This example illustrates the implementation of the method according to the invention for the manufacture of a part made of austenitic steel of grade 316L comprising inclusions of a luminophoric compound of the YAG type doped with cerium and chromium. Before manufacturing the part as such, a mixture of powders is prepared beforehand, comprising the powder consisting exclusively of austenitic steel 316L and a precursor powder of the luminophoric compound, this precursor powder consisting exclusively of a compound of the YAG type doped with cerium Ce. 3+. To do this, a 316L austenitic steel powder (154 g) meeting the same characteristics as those defined below and a precursor powder of the luminophore compound, in this case cerium-doped YAG (8 g) with a particle size ranging from 6.6 µm to 37.3 µm are placed in a bottle. The bottle is then closed and fixed to a Turbula® stirrer, the model being close to the Turbula® type T2F with dimensions of 500*600*400 mm, a maximum bottle load ranging from 6 to 10 kg and a movement frequency ranging from 23 to 101 min -1 The bottle is fixed to a basket by elastic bands and then three-dimensional pulsating movements are applied to it for 18 hours. Then, in a first step, 434 layers of 316L austenitic steel are deposited from a powder with a particle size ranging from 15 µm to 45 µm, an apparent density of 4.42 g / cm 2, a flowability of 13 s / 50 g (determined using a Hall cone), each layer being deposited by a laser powder bed fusion process10 (LPBF technique) with a fibered and ytterbium-doped infrared laser with a wavelength of 1064 nm and a spot size of 55 µm, the other parameters used being the following: -Laser power: 165W; -Scanning speed: 950 mm / s; 15 -Inter-bead distance: 50 µm and layer thickness: 30 µm. In a second step, starting from the above-mentioned mixture, 33 layers are deposited, each layer being deposited by a laser powder bed fusion process (LPBF technique) with a fibered and ytterbium-doped infrared laser having a wavelength of 1064 nm and a spot of 55 µm, the other20 parameters used being the following: -Laser power: 80 W; -Scanning speed: 350 mm / s; -Inter-cord distance: 50 µm and layer thickness: 30 µm.whereby the luminophoric compound is inserted, with a thickness25 of 1 mm, on the last manufacturing layers of the metallic compound, as illustrated in Figure 3 representing a photograph of a section of the sample with insertion of the luminophoric compound, the dark particles corresponding to the luminescent particles. Laser spectroscopy tests for an excitation wavelength30 of 405 nm were carried out according to different spots (indicated in Figure 3, by squares 40437DEL-P 17 numbered respectively 2, 4, 5, 6, 7, 9, 10, 15, 18 and 20), the results being reported in Figure 4, illustrating the evolution of the intensity I (in arbitrary units u.a) as a function of wavelength λ (in nm), curve a) corresponding to spot 2 of the sample in Figure 3, curve b) to spot 4 of the sample in Figure 3, curve c) to spot 5 of sample 5 in Figure 3, curve d) to spot 6 of the sample in Figure 3, curve e) to spot 7 of the sample in Figure 3, curve f) to spot 9 of the sample in Figure 3, curve g) to spot 10 of the sample in Figure 3, curve h) to spot 15 of the sample in Figure 3, curve i) to spot 18 of the sample in Figure 3 and curve j) to spot 20 of the sample in Figure 3. 10 The spectrum illustrates a broad band with a peak around 540 nm, which corresponds to the emission due to cerium.Compared to the initial emission before fabrication (peaks around 570 nm), the cerium band after fabrication is characterized by a shift to the left, which is explained by the fact that the crystalline environment around the Ce ion after fabrication has changed (presence of Cr and potentially other elements of 316L steel in the YAG matrix) and this therefore leads to a shift towards shorter wavelengths. Then, the area from 650 to 750 nm corresponds to the chromium emission. In particular, the peak at 688 nm is the characteristic peak of the R-lines of doped Cr in the YAG matrix. It is also noted that the particles do not all have the same intensity. The intensity depends on the crystallinity of the particle, the defects present in the luminescent matrix as well as the energy transfer between cerium and chromium.

Claims

40437DEL-P 18 CLAIMS 1. A method of manufacturing a metal alloy part by additive manufacturing, said metal alloy comprising a metal element A and said part 5 further comprising inclusions of a luminophor compound consisting of a metal oxide doped with said metal element A, said method comprising at least one step of forming a layer comprising said metal alloy comprising a metal element A and inclusions of said luminophor compound by an additive manufacturing technique chosen from laser melting of projected powder and laser melting on a powder bed, from a mixture comprising a metal alloy powder comprising the metal element A and a precursor powder of said luminophor compound, said precursor powder consisting of a powder of said metal oxide optionally doped with a metal element B different from said metal element A, said luminophor compound being formed in situ,when implementing the additive manufacturing technique, by atomic diffusion of a portion of the metallic element A of the metallic alloy to the metallic oxide and exchange of said metallic element A with a metallic element of the metallic oxide.

2. The method of claim 1, further comprising at least one step of forming a layer consisting of said metallic alloy comprising a metallic element A by an additive manufacturing technique selected from laser melting of projected powder and laser melting on a powder bed from a powder consisting of a metallic alloy powder comprising the metallic element A.

3. The method of claim 1 or 2, wherein the metallic alloy of the metallic alloy powder is selected from iron alloys, aluminum alloys, titanium alloys, nickel alloys, copper alloys and steels, in particular stainless steels. 40437DEL-P 19 4. Method according to claim 3, wherein, when the metal alloy is a steel, this steel is an austenitic steel, advantageously chosen from 316L steel, 304L steel and 1.4404 steel. 5 5. Method according to any one of claims 1 to 4, wherein the metallic element A is chosen from In, Sn, Pb, Sb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Pd, Ag, Ir, Pt and Au, advantageously chosen from Cr, Ce, Fe and Mn and is, preferably, Cr. 10 6. Method according to claim 1 or 2, wherein the metal alloy is steel comprising, as metallic element A, chromium.

7. The method of claim 6, wherein the metal alloy comprises, in addition to chromium, one or more elements selected from manganese, phosphorus, sulfur, silicon, nickel, molybdenum, cobalt and mixtures thereof. 8.Method according to any one of claims 1 to 7, in which the precursor powder consists of a powder of said metal oxide doped with a metal element B different from the metal element A, this metal element B being chosen from In, Sn, Pb, Sb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Pd, Ag, Ir, Pt and Au, advantageously chosen from Cr, Ce, Fe and Mn and being, preferentially, Ce. 25 9. Method according to any one of claims 1 to 8, in which the metal oxide of the precursor powder of the phosphor compound is an oxide of one or more metals chosen from Li, K, Mg, Ca, Sr, Ba, Sc, Y, La, Lu, Ti, Zr, Hf, V, Nb, Ta, Zn, Cd, B, Al, Ga, Si and Ge. 40437DEL-P 20 10. The method of claim 9, wherein the metal oxide of the precursor powder of the phosphor compound is selected from Li2O, K2O, MgO, CaO, SrO, BaO, Sc2O3, Y2O3, La2O3, Lu2O3, TiO2, ZrO2, HfO2, V2O5, Nb2O5, Ta2O5, ZnO, CdO, B2O3, Al2O3, Ga2O3, SiO2, GeO2, Y3Al5O 12 , YAlO3, Y4Al2O9, Sr4Al2O7, Sr3Al2O6, SrAl2O4, SrAl4O7, Sr4Al 12 O 19 , 5 SrAl 12 O 19 , LiAlO2, LaAlO3, MgGa2O4, CaAl2O 4, ZnAl2O 4, CaGa2O 4, CaGa4O, BaAl2O4, CaAl4O7, LiAl5O8, KAI 11 O 17 , KGa 11 O 17 , BaMgAl 10 O 17 and that 0.5 Ba 0.5 Al 12 O 19 , advantageously chosen from garnets, spinels and perovskites, preferentially chosen from Y3Al5O 12 , BaAl2O4, SrAl2O4 and YAlO3 and, more preferably still, is Y3Al5O 12. 10 11. The method of claim 10, wherein the phosphor compound, when the metallic element A is chromium, is a garnet-type oxide having the formula Y3Al5O12 doped with chromium.

12. The method of claim 10, wherein the phosphor compound, when the metallic element A is chromium, is a garnet-type oxide having the formula Y3Al5O 12 doped with cerium and chromium.

13. The method of claim 12, wherein, when the phosphor compound is a garnet-type compound of formula Y3Al5O 12 doped with chromium and cerium, the precursor powder of said luminophor compound is a garnet-type compound powder of formula Y3Al5O 12 doped with cerium.

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