A method for manufacturing a metallic part by additive manufacturing, comprising inclusions of at least one luminescent compound

Abstract

The invention relates to a method for manufacturing a part made of a metal alloy 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 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 phosphor compound by an additive manufacturing technique selected from laser melting of projected powder and laser melting of powder bed, from a powder of metal alloy 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 different from said metal element A, said phosphor compound being formed in situ,During the implementation of the additive manufacturing technique, atomic diffusion of a portion of the metallic element A from the metallic alloy towards the metallic oxide and exchange of said metallic element A with a metallic element from the metallic oxide.

Description

Title of the invention: Method for manufacturing by additive manufacturing a metal part comprising inclusions of at least one luminescent compound technical field

[0001] 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 phosphor compound. The present invention naturally finds its application in all types of industries wishing to design metal parts exhibiting optical properties through the incorporation of phosphor compound(s) into said parts.

[0002] Conventionally, metal alloy parts containing additives are prepared by a high-energy mechanical co-grinding step (for example, using a ball mill or an attrition mill) of a powder of the metal alloy intended for use in the part and a powder of the phosphor compound. This co-grinding step is followed by a sintering step of the powder mixture to form the desired metal part. Manufacturing metal alloy parts by this method does not easily allow for the production of parts with highly complex shapes, due to the difficulty of obtaining suitable molds for such shapes.

[0003] Thus, in view of what already exists, the authors of the present invention have proposed to develop a method for manufacturing a part in metallic alloy using a specific additive manufacturing technique and the resulting advantages, such as the operating conditions to allow the formation of the luminophore compound(s) included in said part and a greater variety of shapes that can be achieved, which makes it possible to broaden the field of application in all areas requiring the use of metallic parts with luminophore properties. Description of the invention

[0004] Thus, the invention relates to a method for manufacturing a part made of a metal alloy by additive manufacturing, said metal alloy comprising a metal element A and said part further comprising inclusions of a luminescent 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 luminescent compound by an additive manufacturing technique selected from laser powder melting and laser powder bed fusion, from a metal alloy powder comprising the metal element A and a precursor powder of said compound luminophore, said precursor powder consisting of a powder of said metal oxide optionally doped with a metal element different from said metal element A, said luminophore compound being formed in situ, during the implementation of the additive manufacturing technique, by atomic diffusion of a part of the metal element A from the metal alloy to the metal oxide and exchange of said metal element A with a metal element of the metal oxide.

[0005] The metallic alloy may be steel comprising chromium as element A. More specifically, the metallic 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.

[0006] More particularly, the metal alloy of the metal part can be austenitic steel, for example, an austenitic steel of grade 1.4404 or 316L.

[0007] The phosphorous compound consisting of a metal oxide doped with said metal element A may be a metal oxide doped with chromium (in which case element A corresponds to chromium), it being understood that this doped metal oxide must exhibit luminophoric properties, that is to say, an ability to emit light after excitation. More particularly, the phosphorous compound may be a garnet-type oxide with the formula Y3Al50i2 (also known by the acronym YAG) doped with chromium (denoted YAG: Cr3+), which means in other words that a portion of the aluminum in YAG is substituted by chromium, said oxide being able to be doped, in addition, with another metallic element, such as cerium.More specifically, the luminescent compound can be a garnet-type oxide with the formula Y3 A15O12 doped with cerium and chromium, with cerium substituting at the dodecahedral sites of yttrium and chromium substituting at the octahedral sites of aluminum. The YAG compound doped with both chromium Cr3+ and cerium Ce3+ exhibits luminescence in both the red (between 650 nm and 750 nm) due to the in situ doping of Cr3+ and the green / yellow (between 500 nm and 575 nm) due to the Ce3+ initially present in the YAG crystal.

[0008] Alternatively, the luminophore compound may be a chromium-doped spinel-type oxide.

[0009] In addition, the process may include at least one step of forming a layer made up of said metal alloy comprising a metal element A by an additive manufacturing technique selected from laser melting of projected powder and laser melting of powder bed from a powder consisting of a metal alloy powder comprising the metal element A.

[0010] Thus, the process covers the manufacture of the following parts:

[0011] -a part wherein each layer formed by the process is a layer comprising said metallic alloy comprising a metallic element A and inclusions of said luminophore compound, in which case there will be no implementation of the formation step mentioned just above;

[0012] -in the contrary case, that is to say, in the case where there will be implementation, one or more times, of the formation step mentioned just above, a part of which at least one of the layers formed by the process is a layer comprising said metal alloy comprising a metal element A and inclusions of said luminophore compound and at least one of the layers formed by the process is a layer made up of said metal alloy comprising a metal element A and this regardless of the way in which these layers are arranged with respect to each other.

[0013] Whether for one or the other of the aforementioned training steps, these are implemented by a specific additive manufacturing technique chosen from laser melting of projected powder and laser melting on powder bed.

[0014] In particular, according to a first embodiment, each step of the formation of a layer comprising said metal alloy including a metal element A and inclusions of said luminophore compound and, where applicable, each step of a layer made up of said metal alloy including a metal element A 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 Anglo-Saxon terminology "Laser Metal Deposition") or DED process (corresponding to the Anglo-Saxon terminology "Directed Energy Deposition").In general, the laser powder bed fusion process relies on the combined use of a high-power laser and a powder delivery device (typically a nozzle) with coaxial or side-injection. In practical terms, for each layer to be deposited, the powder or powder mixture, carried by a carrier gas (e.g., argon, helium, nitrogen), is melted, in whole or in part, upon contact with the laser beam. The melting process can be completed upon contact with the liquid metal bath formed on the substrate (or build platform) resulting from the laser-material interaction, before the entire assembly (molten powder + liquid metal bath resulting from the melting of the lower layers) solidifies. The movement of the laser, the powder delivery device, and the substrate is controlled relative to a digital model defined during the development of the part to be produced.

[0015] The laser melting process of projected powder depends on several parameters, including the characteristics of the powder or powder mixture, the nature and power of the laser, the laser scanning speed, the powder flow rate, the desired layer thickness, and the distance between each manufacturing bead. The man of the The craftsman will determine, if necessary, through preliminary tests, these different parameters, depending on the metal part he wishes to obtain.

[0016] In particular, when the phosphor compound is a cerium- and chromium-doped YAG compound and the sprayed powder mixture comprises 316L steel powder and cerium-doped YAG powder, the parameters of the layer formation step(s) comprising 316L steel and cerium- and chromium-doped YAG inclusions may be as follows:

[0017] -for an OPTOMEC machine, an ytterbium-doped fiber laser, a wavelength of 1064 nm and a laser spot of 1.2 mm for a working distance fixed at 12 mm;

[0018] -a laser power ranging from 300 W to 1000 W;

[0019] -a scanning speed ranging from 1 mm / s to 100 mm / s;

[0020] -a powder flow rate ranging from 0.5 rpm to 20 rpm (rpm corresponding to the rotation speed of the powder distribution motor);

[0021] -an inter-cord distance ranging from 0.1 mm to 2 mm and a layer thickness of 0.1 mm to 2 mm.

[0022] More specifically, when the luminophore compound is a cerium and chromium doped YAG type compound and the precursor powder of said compound is a cerium doped YAG type compound powder, the laser fluence, during the formation step, advantageously ranges from 265 W / mm2 to 900 W / mm2.

[0023] In particular, when the sprayed powder is 316L steel powder, the parameters of the step(s) for forming the layer made of 316L steel are as follows:

[0024] - a spherical powder morphology and advantageously exhibiting a particle size ranging from 45 pm to 106 pm;

[0025] -for an OPTOMEC machine, an 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;

[0026] -a laser power ranging from 100 W to 1500 W;

[0027] -a scanning speed ranging from 1 mm / s to 100 mm / s;

[0028] -a powder flow rate ranging from 0.5 rpm to 20 rpm (rpm corresponding to the speed of rotation of the powder distribution motor);

[0029] -an inter-cord distance ranging from 0.1 mm to 2 mm and a layer thickness of 0.1 mm to 2 mm.

[0030] For each step of forming a layer comprising said metal alloy including a metal element A and inclusions of said luminophore compound, the metal alloy powder and the precursor powder of said luminophore 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 tanning via two separate powder dispensers.

[0031] In the case where the metal alloy powder and the precursor powder of said luminescent compound are dispensed simultaneously via two separate powder dispensers (it being understood that both types of powders must exhibit good flowability), the metal alloy powder and the precursor powder of said luminescent 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, it is possible to independently adjust the flow rate of the metal alloy powder and the flow rate of the precursor powder according to the desired percentage of luminescent compound incorporation. For example, to obtain a 6.25% incorporation of the luminescent compound during the manufacturing of the layer in question, the flow rate of the metal alloy powder can be set to 3.75 rpm and the flow rate of the precursor powder can be set to 0.75 rpm.

[0032] According to a second embodiment, each step of forming a layer comprising said metal alloy including a metal element A and inclusions of said luminophore compound and, where appropriate, each step of forming a layer made up of said metal alloy including a metal element A can be carried out by a laser powder bed fusion process, also known as LPBF (corresponding to the Anglo-Saxon terminology "Laser Powder Bed Fusion") or SLM (corresponding to the Anglo-Saxon terminology "Selective Laser Melting") or LBM (corresponding to the Anglo-Saxon terminology "Laser Beam Melting").In general, the LPBF process involves spreading powder onto a build platform and then passing a laser over the powder to melt it. The molten material then solidifies upon cooling. This sequence of steps is repeated as many times as necessary until the desired part is obtained. The laser path is defined by a digital file (CAD file followed by a slicer that cuts the part into layers).

[0033] The laser powder bed fusion process depends on several parameters, including the characteristics of the powder, the type and power of the laser, the laser scanning speed, the layer thickness, and the distance between each fabrication bead. Those skilled in the art will determine these various parameters, if necessary, through preliminary tests, depending on the metal part they wish to produce.

[0034] In particular, when the phosphor compound is a cerium- and chromium-doped YAG type compound and the mixture comprises 316L steel powder and cerium-doped YAG powder, the parameters of the layer formation step(s) comprising 316L steel and cerium- and chromium-doped YAG inclusions may be as follows:

[0035] -for a TruPrint 1000 machine, an ytterbium-doped fiber laser, a wavelength of 1064 nm and a laser spot of 55 pm;

[0036] -a laser power ranging from 20 W to 200 W;

[0037] -a scanning speed ranging from 10 mm / s to 1300 mm / s;

[0038] -a layer thickness ranging from 10 pm to 100 pm;

[0039] -an inter-cord distance ranging from 10 pm to 150 pm.

[0040] More specifically, when the luminophore compound is a cerium and chromium doped YAG type compound and the precursor powder of said compound is a cerium doped YAG type compound powder, the laser fluence, at each formation step, advantageously ranges from 8400 W / mm2 to 84000 W / mm2.

[0041] In particular, when the powder is 316L steel powder, the parameters of the step(s) for forming the layer made of 316L steel are as follows:

[0042] -for a TruPrint 1000 machine, an ytterbium-doped fiber laser, a wavelength of 1064 nm and a laser spot of 55 pm;

[0043] -a laser power ranging from 20 W to 500 W;

[0044] -a scanning speed ranging from 10 mm / s to 3000 mm / s;

[0045] -a layer thickness ranging from 10 pm to 100 pm;

[0046] -an inter-cord distance ranging from 10 pm to 150 pm.

[0047] The powders for the LPBF process should advantageously have a spherical morphology and a particle size ranging from 15 pm to 45 pm.

[0048] Whether for the laser powder projection fusion technique and laser powder bed fusion, the authors of the present invention have been able to demonstrate the in situ formation of the luminophore compound concurrently with the implementation of the chosen technique, the energy engaged during this implementation allowing the atomic diffusion of said metal element A in the metal oxide and the exchange of said metal element A with a metal element of the metal oxide, this process being able to be demonstrated by laser spectroscopy tests and by analyzing the luminescent emission bands of the luminophore compound obtained.

[0049] When the luminophore compound is a garnet-type compound of formula Y3A150i2 doped with chromium and cerium, the precursor powder of said luminophore compound may be a powder of garnet-type compound of formula Y3A150i2 doped with cerium.

[0050] Before implementing the aforementioned formation steps, and when the technique used is the LPBF technique or, failing that, when the technique used is the laser powder fusion technique and one of the powders does not exhibit good flowability, the process may include a preliminary mixing step comprising the powder of said metal alloy and a precursor powder of said luminescent compound. This preliminary mixing step is This preparation step is advantageously suited when at least one of the powders does not have a morphology conducive to good flowability (for example, a powder with a spherical morphology and a particle size ranging from 45 µm to 106 µm, in the case where the chosen technique is laser melting on projected powder). This preparation step may consist of bringing the metal alloy powder into contact with the precursor powder and subjecting the resulting mixture to any mixing techniques that improve its flowability. In particular, the contact may be carried out in a rotary mixer or in a container subjected to agitation by attachment to a stirrer.

[0051] In the latter case, deagglomerating objects, such as marbles, can be added to the container.

[0052] In particular, these deagglomerating objects, such as beads, exhibit sufficient resistance and do not induce contamination of the powder mixture. These may be, in particular, ceramic beads or metallic beads, and more specifically, steel beads.

[0053] The balls can have a diameter ranging from 5 mm to 15 mm, preferably from 3 mm to 7 mm and, even more specifically, balls with a diameter of about 5 mm.

[0054] The volume ratio between the deagglomerating objects, such as beads, and the powders (atomized powder + oxide powder(s)) can range from 0.5 to 3.

[0055] The reservoir, in which the powders and the powder deagglomerating agents are placed, may be made of plastic or metal, provided that the material is sufficiently strong to withstand the shocks induced by the mixing operation. The reservoir may have a volume of 1 to 2 liters.

[0056] The reservoir advantageously has a filling rate ranging from 30 to 70% (for example, equal to 40%), this filling rate corresponding to the % of the total volume of the reservoir occupied by the powders and the powder deagglomeration objects.

[0057] The tank is attached to an agitator which imparts an agitation motion to the tank. This agitator may be, in particular, a three-dimensional agitator, such as those marketed under the Turbula® brand. In such an agitator, the tank is subjected to a three-dimensional movement due to the action of the agitator, and the contents of the tank (namely, the powders and the powder deagglomerating agents) are thus subjected to a continuously changing pulsating motion.

[0058] Finally, whatever additive manufacturing technique is chosen, the layer formation steps are repeated as many times as possible until the desired part is obtained with a chosen thickness and shape.

[0059] Other advantages and features of the invention will appear in the description detailed but not exhaustive list below. Brief description of the drawings

[0060] [Fig.1] represents a photograph of a cross-section of the sample with insertion of the luminophore compound obtained according to Example 1, the dark particles corresponding to the luminescent particles, the enlarged views above the photograph corresponding to the different spots for the laser spectroscopy tests.

[0061] [Fig.2] is a graph illustrating the evolution of the intensity I (in arbitrary units ua) as a function of the wavelength X (in nm), curve a) corresponds to spot 1 of the sample in [Fig.1], curve b) to spot 2 of the sample in [Fig.1], curve c) to spot 3 of the sample in [Fig.1] and curve d) to spot 4 of the sample in [Fig.1].

[0062] [Fig.3] represents a photograph of a cross-section of the sample with insertion of the luminophore compound obtained according to example 2.

[0063] [Fig.4] represents a graph illustrating the evolution of the intensity I (in ar units bitrary ua) as a function of wavelength X (in nm), curve a) corresponding to spot 2 of the sample in [Fig.3], curve b) to spot 4 of the sample in [Fig.3], curve c) to spot 5 of the sample in [Fig.3], curve d) to spot 6 of the sample in [Fig.3], curve e) to spot 7 of the sample in [Fig.3], curve f) to spot 9 of the sample in [Fig.3], curve g) to spot 10 of the sample in [Fig.3], curve h) to spot 15 of the sample in [Fig.3], curve i) to spot 18 of the sample in [Fig.3] and curve j) to spot 20 of the sample in [Fig.3].

[0064] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS EXAMPLE 1

[0065] This example illustrates the implementation of the process according to the invention for the LMD manufacturing of a part in 316L grade austenitic steel comprising inclusions of a cerium and chromium doped YAG type luminophore compound.

[0066] Before manufacturing the part as such, a powder mixture is prepared in advance comprising the powder consisting exclusively of 316L austenitic steel and a precursor powder of the luminophore compound, this precursor powder consisting exclusively of a cerium Ce3+ doped YAG type compound. To do this, the 316L austenitic steel powder has a particle size ranging from 45 pm to 106 pm, an apparent density of 4.02 g / cm3, a tapped density of 4.77 g / cm3 and a flowability of 17.70 s / 50 g (determined with a Hall cone) and the precursor powder of the luminophore compound has a particle size ranging from 6.6 pm to 37.3 pm at a rate of 5% mass relative to the total mass of the mixture are mixed by mechanosynthesis for 15 hours at a rotation speed of 400 rpm.

[0067] Then, initially, 8 layers are deposited from a powder consisting exclusively of 316L austenitic steel, each layer being deposited using an OPTOMEC laser projection machine with a ytterbium-doped, fiber-reinforced infrared laser having a wavelength of 1064 nm and a spot size of 1.2 mm, the other parameters used being as follows:

[0068] -Working distance: 12 mm;

[0069] -Laser power: 450 W;

[0070] -Scanning speed: 5 mm / s;

[0071] -Powder flow rate: 2 rpm;

[0072] -Inter-cord distance: 0.84 mm and layer thickness: 0.5 mm.

[0073] In a second step, the mixture thus obtained is also deposited by LMD on the layers previously deposited by LMD, in the form of two layers, according to a laser fining of 398 W / mm2 (laser power delivered per cm2), whereby the luminophore compound is inserted on the last manufacturing layers of the metallic compound, as illustrated in [Fig.1] representing a photograph of a cross-section of the sample with insertion of the luminophore compound, the dark particles corresponding to the luminescent particles.

[0074] Laser spectroscopy tests for an excitation wavelength of 405 nm were carried out according to different spots (indicated on [Fig.1], spot 1, spot 2, spot 3 and spot 4), the results being reported on [Fig.2], illustrating the evolution of the intensity I (in arbitrary units ua) as a function of the wavelength X (in nm), curve a) corresponding to spot 1 of the sample of [Fig.1], curve b) to spot 2 of the sample of [Fig.1], curve c) to spot 3 of the sample of [Fig.1] and curve d) to spot 4 of the sample of [Fig.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 peaks ranging from 650 nm to 750 nm corresponding to a new phase corresponding to Y3Al50i2: Cr or in other words to the chromium-doped YAG compound.Given that the simultaneous emission of Ce3+ and Cr3+ ions is observed, this proves that the phosphor compound is a YAG compound doped with both cerium (a remnant of the original doping) and chromium (resulting from the in situ atomic diffusion of chromium from the metallic alloy to the YAG compound during LMD deposition, thanks to the high temperatures involved in this deposition). While not bound by theory, the chromium present in 316L steel diffuses towards the precursor YAG compound, Ce, and occupies the space of some of the aluminum at the octahedral sites of the YAG crystallographic structure. The incorporation of chromium induces emission peaks in the red region (between 650 nm and 750 nm).

[0075] The particles of the luminophore compound have an average size of 200 pm, this which corresponds to a size greater than the size of the precursor powder, which could be explained by a coalescence phenomenon during the melting of the powder followed by solidification.

[0076] Alternatively, a metal part was prepared on the basis of the same conditions as those mentioned above, except that the preparation of the mixture was obtained using a three-dimensional Turbula-type agitator.

[0077] To do this, 316L steel powder (237.5 g) and YAG :Ce powder (12.5 g) at a rate of 2% mass relative to the total mass of the powder mixture are placed in the same plastic bottle (of the VWR brand, in translucent PE-BD and IL) in the presence of steel balls (1010 g) of 5 mm diameter, the filling rate of the bottle being 40%.

[0078] The bottle is closed and then fixed 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 1 and agitation is carried out for a period of 18 hours, the container being fixed to a cradle by elastic bands and then rhythmic pulsating three-dimensional movements are applied to it during this period.

[0079] Once the mixing is complete, the contents of the bottle are recovered and the powder and beads are separated using a simple sieve.

[0080] The metal part thus obtained is also subjected to laser spectroscopy tests at an excitation wavelength of 405 nm, which also allow the detection of the chromium-doped YAG phase. This demonstrates that the mixing technique for preparing the powder mixture has no influence on obtaining the phosphor compound. Furthermore, it appears that the chromium-doped YAG phase is present both with the powder mixture containing 2% YAG powder: Ce and with the powder mixture containing 5% YAG powder: Ce, which shows that the quantity of YAG powder: Ce in the mixture has no influence on obtaining this phase. EXAMPLE 2

[0081] This example illustrates the implementation of the process according to the invention for the manufacture of a part in 316L grade austenitic steel comprising inclusions of a cerium and chromium doped YAG type luminophore compound.

[0082] Before manufacturing the part itself, a powder mixture is prepared beforehand, comprising a powder consisting exclusively of 316L austenitic steel and a precursor powder of the phosphor compound, this precursor powder consisting exclusively of a cerium-doped Ce3+ YAG compound. For this purpose, 154 g of 316L austenitic steel powder meeting the same characteristics as those defined below and 8 g of a precursor powder of the phosphor compound, in this case cerium-doped YAG, having a particle size ranging from 6.6 pm to 37.3 pm are placed in a bottle. The bottle is then closed and attached to a Turbula® shaker, the model being similar 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. The bottle is attached to a cradle by elastic bands and then rhythmic pulsating three-dimensional movements are applied to it for 18 hours.

[0083] Then, initially, 434 layers made of 316L austenitic steel are deposited from a powder having a particle size ranging from 15 pm to 45 pm, an apparent density of 4.42 g / cm2, a flowability of 13 s / 50 g (determined using a Hall cone), each layer being deposited by a laser powder bed fusion process (LPBF technique) with an ytterbium-doped, fiber-reinforced infrared laser having a wavelength of 1064 nm and a spot size of 55 pm, the other parameters used being the following:

[0084] -Laser power: 165 W;

[0085] -Scanning speed: 950 mm / s;

[0086] -Inter-cord distance: 50 pm and layer thickness: 30 pm.

[0087] In a second step, 33 layers are deposited from the aforementioned mixture, each layer being deposited by a laser powder bed fusion process (LPBF technique) with an ytterbium-doped, fiber-reinforced infrared laser having a wavelength of 1064 nm and a spot size of 55 pm, the other parameters used being as follows:

[0088] -Laser power: 80 W;

[0089] -Scanning speed: 350 mm / s;

[0090] -Inter-cord distance: 50 pm and layer thickness: 30 pm.

[0091] whereby the luminophore compound is inserted, with a thickness of 1 mm, on the last layers of manufacture of the metallic compound, as illustrated in [Fig.3] representing a photograph of a cross-section of the sample with insertion of the luminophore compound, the dark particles corresponding to the luminescent particles.

[0092] Laser spectroscopy tests for an excitation wavelength of 405 nm were carried out at different spots (indicated in [Fig. 3] by squares numbered 2, 4, 5, 6, 7, 9, 10, 15, 18, and 20, respectively), the results being shown in [Fig. 4], illustrating the evolution of the intensity I (in arbitrary units α) as a function of the wavelength X (in nm), curve a) corresponding to spot 2 of the sample in [Fig. 3], curve b) to spot 4 of the sample in [Fig. 3], curve c) to spot 5 of the sample in [Fig. 3], curve d) to spot 6 of the sample in [Fig. 3], curve e) to spot 7 of the sample in [Fig. 3], curve f) to spot 9 of the sample in [Fig. 3], the curve g) at spot 10 of the sample in [Fig. 3], curve h) at spot 15 of the sample of [Fig.3], curve i) at spot 18 of the sample of [Fig.3] and curve j) at spot 20 of the sample of [Fig.3].

[0093] The spectrum illustrates a broad band with a peak around 540 nm, corresponding 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 leftward shift, 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 from 316L steel in the YAG matrix), thus leading to a shift towards shorter wavelengths. The region from 650 to 750 nm then corresponds to the emission of chromium. In particular, the peak at 688 nm is the characteristic peak of the R-Unes of Cr doped in the YAG matrix.

[0094] It is also noted that the particles do not all exhibit the same intensity. The intensity depends on the crystallinity of the particle, the defects present in the luminescent matrix, and the energy transfer between the cerium and the chromium.

Claims

Demands

1. 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 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 phosphor compound by an additive manufacturing technique selected from laser powder melting and laser powder bed melting, 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 other than said metal element A, said phosphor compound being formed in situ,During the implementation of the additive manufacturing technique, atomic diffusion of a portion of the metallic element A from the metallic alloy towards the metallic oxide and exchange of said metallic element A with a metallic element from the metallic oxide.

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

3. A method according to claim 1 or 2, wherein the metal alloy is steel comprising, as element A, chromium.

4. A process according to any one of the preceding claims, wherein the metal alloy is steel comprising, in addition to chromium, one or more elements selected from manganese, phosphorus, sulfur, silicon, nickel, molybdenum, cobalt and mixtures thereof.

5. A method according to any one of the preceding claims, wherein the metal alloy is an austenitic steel.

6. A method according to any one of the preceding claims, wherein the metal alloy is an austenitic steel of grade 1.4404 or 316L.

7. A method according to any one of the preceding claims, wherein the luminophore compound, where the metallic element A is chromium, is a garnet-type oxide corresponding to the formula Y3Al50i2 doped with chromium.

8. A process according to any one of the preceding claims, wherein the luminophore compound, where the metallic element A is chromium, is a garnet-type oxide corresponding to the formula Y3Al50i2 doped with cerium and chromium.

9. A method according to claim 7, wherein, when the luminophore compound is a garnet-type compound of formula Y3A150i2 doped with chromium and cerium, the precursor powder of said luminophore compound is a garnet-type compound powder of formula Y3A15 On doped with cerium.

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