A noble metal low-defect laser powder bed fusion forming method and noble metal component

Abstract

The present application belongs to the technical field of precious metal additive manufacturing, and particularly relates to a low-defect laser powder bed fusion forming method for precious metals and a precious metal component. The present application first determines or obtains the absorption rate of the precious metal powder under the laser wavelength condition of the laser powder bed fusion equipment, and converts the nominal volume energy density into an effective absorption volume energy density index; then determines the laser power, scanning speed, scanning spacing and precious metal powder layer thickness based on the low-defect effective absorption volume energy window, to realize the low-defect forming of the precious metal. The present application considers the absorption rate of the precious metal material, converts the empirical process parameters into a quantifiable and transferable forming window, realizes the stable preparation of the dense component and the dot array complex component of the precious metal, and solves the problems of narrow process window, defect sensitivity, difficult parameter transfer and difficult stable forming of complex structures in the process of laser powder bed fusion forming of the precious metal.

Description

Technical Field

[0001] This invention belongs to the field of precious metal additive manufacturing technology, specifically relating to a method for forming a low-defect laser powder bed of precious metals and a precious metal component. Background Technology

[0002] Platinum group metals include platinum, palladium, iridium, rhodium, ruthenium, and osmium. These materials possess excellent chemical stability, corrosion resistance, high-temperature mechanical properties, and catalytic activity, making them irreplaceable in applications such as high-end functional devices, components for highly corrosive environments, electrochemical functional components, and high-temperature load-bearing structural parts.

[0003] Pure platinum, as a typical representative of the platinum group metals, has a high melting point and expensive raw material costs. Furthermore, its powder absorption rate under near-infrared laser light is relatively low, resulting in a narrow range of stable processing options when using laser powder bed melting (LPBF). Traditional manufacturing methods such as casting, forging, and machining are limited by the difficult-to-machine characteristics of precious metals and the geometric limitations of the processes themselves. This makes it difficult to efficiently fabricate complex three-dimensional configurations, lightweight lattice structures, and integrated precision precious metal components, thus hindering structural innovation and engineering applications of precious metal functional components.

[0004] Laser powder bed fusion additive manufacturing (LPBF) technology offers a high degree of freedom in structural design, providing a feasible path for the integrated manufacturing of complex precious metal components. However, when precious metals undergo LPBF forming, incomplete fusion porosity, spherical pores, and keyhole-type voids are easily generated, accompanied by multiple defects such as molten metal splashing and thermal stress-induced structural instability, making it difficult to guarantee the density, dimensional accuracy, and performance of the components. Summary of the Invention

[0005] The purpose of this invention is to provide a method for low-defect laser powder bed fusion forming of precious metals and precious metal components. The method provided by this invention takes into account the material absorption rate and transforms empirical process parameters into quantifiable and transferable forming windows, thereby achieving stable fabrication of dense precious metal components and complex lattice components, and solving the problems of narrow process windows, defect sensitivity, difficulty in parameter transfer, and difficulty in stable forming of complex structures in the laser powder bed fusion forming (LPBF) process of precious metals.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for determining low-defect forming parameters in noble metal laser powder bed melting, wherein the low-defect forming parameters include: laser power, scanning speed, scanning spacing, and the thickness of the noble metal powder bed layer; the method includes the following steps: Determine or obtain the absorption rate of precious metal powder under the laser wavelength λ of a laser powder bed melting device. Establish an effective absorbed volumetric energy density index for precious metal powders, wherein the effective absorbed volumetric energy density index is the actual absorbed energy per unit volume, and the calculation formula for the actual absorbed energy per unit volume is as shown in formula (1): Formula (1); In formula (1): This represents the actual energy absorbed per unit volume. The absorption rate of precious metal powder under the laser wavelength λ in a laser powder bed melting device. P is Laser power, For laser scanning rate, h For scanning spacing, t The thickness of the powder layer for precious metal powder; Based on the low-defect effective absorption volume energy window of noble metal powder In order to satisfy Under the given conditions, the low-defect forming parameters are determined according to formula (1); E low To avoid defects such as insufficient melting and / or lack of fusion, the lower limit of the actual energy absorbed per unit volume of precious metal powder is determined. E high To avoid any of the defects such as overheating, deep melting, keyholes, and spattering, the upper limit of the actual energy absorbed per unit volume of precious metal powder.

[0007] Preferably, the noble metal powder is a platinum group metal; the platinum group metal includes at least one of Ru, Rh, Pd, Os, Ir and Pt.

[0008] Preferably, the noble metal powder is pure platinum powder; when the laser wavelength λ of the laser powder bed melting equipment is 1070 nm, the absorption rate of the pure platinum powder is... It is 0.2963.

[0009] Preferably, the noble metal powder is pure platinum powder; the pure platinum powder has a low-defect effective absorption volumetric energy window. 48~73 J / mm 3 .

[0010] Preferably, the pure platinum powder has a low-defect effective absorption volume energy window. The center value is 59 J / mm 3 In order to satisfy Equal to the low-defect effective absorption volume energy window Under the condition of the center value, the low-defect forming parameters of pure platinum powder are determined according to formula (1).

[0011] This invention provides a method for low-defect laser powder bed melting and forming of noble metals, comprising the following steps: A precious metal powder is provided, and low-defect forming parameters are obtained according to the determination method described in the above technical solution; the precious metal component is formed by laser powder bed melting method according to the low-defect forming parameters.

[0012] Preferably, the precious metal powder is pure platinum powder, and when the laser wavelength λ of the laser powder bed melting equipment is 1070 nm, the low-defect forming parameters include: laser power of 160~240 W, scanning spacing of 0.095 mm, powder layer thickness of precious metal powder of 0.020 mm, and scanning speed of 470~750 mm / s.

[0013] The present invention provides a precious metal component, characterized in that the precious metal component is prepared by the precious metal low-defect laser powder bed melting forming method described in the above technical solution.

[0014] Preferably, the precious metal component is a pure platinum dense component or a target material component, and the relative density of the pure platinum dense component measured by CT is not less than 99%.

[0015] Preferably, the precious metal component includes a lattice component, a porous component, a thin-walled component, a curved surface component, or a complex three-dimensional component with internal interconnecting channels.

[0016] This invention provides a method for determining low-defect forming parameters in laser powder bed melting (LPBF) of noble metals, and a method for forming low-defect laser powder bed melting of noble metals. This invention's research found that current LPBF process parameter selection and optimization generally rely on nominal volumetric energy density (VOD). VED=P / vht ) Conduct trial and error, in the formula P For laser power, v For laser scanning rate, h For scanning spacing, t To achieve a thicker powder layer, VED The nominal volumetric energy density (LBF) is the energy density at which the laser outputs the light source. This index only reflects the input energy of the laser and does not consider the differences in absorption of specific wavelengths of laser light by different metal powders. For noble metal materials, the powder laser absorptivity varies significantly with the material type and laser wavelength. The nominal volumetric energy density cannot characterize the actual energy coupled and absorbed by the powder, resulting in poor adaptability of the LPBF process parameters. When changing the laser power, powder layer thickness, scanning spacing, or noble metal material system, the debugged process parameters cannot be directly reused, exhibiting poor parameter transferability. Extensive repeated experiments and iterations are required, leading to high R&D costs and making it difficult to achieve stable, low-defect fabrication of dense noble metal components and complex porous lattice components. This invention provides a method for low-defect laser powder bed melting of noble metals based on an effective absorption volumetric energy density window. This method first obtains the absorptivity of the noble metal powder at the laser wavelength and then... The nominal process parameters are converted into effective absorbed volumetric energy density; subsequently, the laser power, scanning speed, scanning spacing, and powder layer thickness are determined based on the effective absorbed volumetric energy window for low defects, thus achieving low-defect forming of noble metals. For pure platinum powder, under 1070 nm laser conditions, the preferred effective absorbed volumetric energy window is 48~73 J / mm. 3 The center of the window is approximately 59 J / mm. 3 This invention further utilizes this process window to fabricate precious metal lattice components such as TPMS. This method can reduce incomplete fusion holes, keyholes, and thermal instability defects during precious metal printing, and enables the transferable fabrication of dense and complex lattice components. Compared with existing technologies, the advantages of this invention are: (1) The present invention upgrades the traditional nominal volumetric energy density to the effective absorbed volumetric energy density, which can reflect the actual energy coupling state of noble metal powder under a specific laser wavelength.

[0017] (2) The present invention screens the parameters of laser powder bed melting (LPBF) of noble metals by absorbing energy density window, which can avoid the defects of incomplete fusion in the low energy region and the defects of keyhole, spatter and thermal instability in the high energy region.

[0018] (3) The present invention provides a parameter migration formula, which can convert parameters between different laser powers, scanning intervals, powder layer thicknesses and precious metal materials, reducing repeated trial and error.

[0019] (4) The present invention can realize high density and low defect forming of precious metals such as pure platinum, and is applicable to dense blocks, thin-walled structures, lattice structures and complex three-dimensional components.

[0020] (5) The present invention extends the low-defect forming window to lattice structures such as TPMS, which can improve the structural design freedom of precious metal components, reduce material usage, and realize the integrated manufacturing of complex functional components. Attached Figure Description

[0021] Figure 1 This is a flowchart of the method for forming low-defect laser powder bed of precious metals according to the present invention; Figure 2 This is a physical image of a pure platinum solid component formed by laser powder bed melting (LPBF) according to the present invention; Figure 3 This is a physical image of a pure platinum lattice component formed by laser powder bed melting (LPBF) according to the present invention; Figure 4 This is a 3D overall pore distribution diagram obtained from a CT scan of Embodiment 1 of the present invention; Figure 5 This is a pore volume distribution diagram obtained from a CT scan of Embodiment 1 of the present invention; Figure 6 This is a 3D overall pore distribution diagram obtained from a CT scan of Comparative Example 1 of this invention; Figure 7 This is a pore volume distribution diagram from a CT scan of Comparative Example 1 of the present invention; Figure 8 The design drawing of the platinum lattice component provided by the present invention. Detailed Implementation

[0022] This invention provides a method for determining low-defect forming parameters in noble metal laser powder bed melting, wherein the low-defect forming parameters include: laser power, scanning speed, scanning spacing, and the thickness of the noble metal powder bed layer; the method includes the following steps: Determine or obtain the absorption rate of precious metal powder under the laser wavelength λ of a laser powder bed melting device. Establish an effective absorbed volumetric energy density index for precious metal powders, wherein the effective absorbed volumetric energy density index is the actual absorbed energy per unit volume, and the calculation formula for the actual absorbed energy per unit volume is as shown in formula (1): Formula (1); In formula (1): This represents the actual energy absorbed per unit volume. The absorption rate of precious metal powder under the laser wavelength λ in a laser powder bed melting device. P is Laser power, For laser scanning rate, h For scanning spacing, t The thickness of the powder layer for precious metal powder; Based on the low-defect effective absorption volume energy window of noble metal powder In order to satisfy Under the given conditions, the low-defect forming parameters are determined according to formula (1); E low To avoid defects such as insufficient melting and / or lack of fusion, the lower limit of the actual energy absorbed per unit volume of precious metal powder is determined. E high To avoid any of the defects such as overheating, deep melting, keyholes, and spattering, the upper limit of the actual energy absorbed per unit volume of precious metal powder.

[0023] In this invention, E low To avoid the lower limit of the actual volumetric energy absorbed by precious metal powders with defects such as insufficient melting and / or lack of fusion, this invention defines it as the lower limit of the effective volumetric energy absorption window for low defects. E highTo avoid any of the defects such as overheating, deep melting, keyholes, and spattering, the upper limit of the actual volumetric energy absorbed by precious metal powder is defined in this invention as the upper limit of the effective volumetric energy absorption window for low defects.

[0024] In this invention, the noble metal powder has a low-defect effective absorption volume energy window. Preferably, the forming performance is determined based on the forming properties of the precious metal component. The lower limit of the forming performance is to avoid incomplete melting and / or lack of fusion defects, and the upper limit of the forming performance is to avoid any one of the following defects: overheating, deep melting, keyhole, and spatter. The precious metal component is a dense precious metal component. The forming performance of the precious metal component is preferably characterized by at least one of the following performance test results: forming state, solid component density test, CT measurement defect analysis and calculation of relative density, microstructure analysis, mechanical property test, and single-pass cladding analysis.

[0025] In a specific embodiment of the present invention, the noble metal powder is pure platinum powder; the noble metal component is a pure platinum dense component, and the CT measurement defects of the pure platinum dense component and the calculated relative density of not less than 99% are used as the low-defect effective absorption volume energy window. The defining indicators.

[0026] In this invention, the relative density is calculated by comparing the measured defect volume of the precious metal component with the overall volume of the sample to obtain density data. The formula for calculating the relative density by CT measurement is: CT relative density = (overall volume - defect volume) / overall volume.

[0027] In this invention, the noble metal powder has a low-defect effective absorption volume energy window. The preferred method for determining the precious metal component sample includes: using precious metal powder as raw material, forming it using a laser powder bed melting method, and preparing a series of precious metal component samples under different forming parameters; analyzing the forming performance of the precious metal component samples, and determining that when the forming performance of the precious metal component sample meets the requirements, it is a low-defect qualified precious metal component sample; substituting the forming parameters of the low-defect qualified precious metal component sample into formula (1), the maximum value obtained is the [value to be filled in]. The minimum value is In this invention, before judging the forming performance, the invention preferably includes visually inspecting the appearance of the precious metal component samples and rejecting those with obviously unqualified appearances. The visual inspection involves observing whether the actual dimensions of the precious metal component samples differ significantly, and whether abnormal sparks occur during the forming process. In severe cases, this can lead to violent splashing, forming failure, and the inability to obtain a precious metal component.

[0028] In this invention, the precious metal powder is pure platinum powder; the precious metal component sample is a pure platinum dense component sample. When the relative density of the pure platinum dense component sample measured by CT is not less than 99%, it is determined to be a low-defect qualified pure platinum dense component sample; substituting the forming parameters of the low-defect qualified pure platinum dense component sample into formula (1), the maximum value obtained is... The minimum value is This means obtaining the low-defect effective absorption volume energy window of pure platinum powder. .

[0029] In this invention, the noble metal powder is preferably a platinum group metal. The platinum group metal preferably includes at least one selected from Ru, Rh, Pd, Os, Ir, and Pt. In a specific embodiment of this invention, the noble metal powder is pure platinum powder.

[0030] In this invention, the precious metal powder is pure platinum powder; when the laser wavelength λ of the laser powder bed melting equipment is 1070 nm, the absorption rate of the pure platinum powder is... It is 0.2963.

[0031] In this invention, the low-defect effective absorption volumetric energy window of the pure platinum powder is preferably 48~73 J / mm². 3 The center value of the low-defect effective absorption volumetric energy window of the pure platinum powder is preferably 59 J / mm². 3 The present invention satisfies Equal to the low-defect effective absorption volume energy window Under the condition of the center value, the low-defect forming parameters of pure platinum powder are determined according to formula (1).

[0032] In this invention, the nominal volumetric energy density window corresponding to the pure platinum powder is preferably 162~246 J / mm². 3 .

[0033] In this invention, the laser scanning rate v Determined by formula (2): ;in, E abs Take any value within the low-defect effective absorption volume energy window. In this invention, the laser scanning rate... v The range is determined by formula (3): (3); This invention provides a method for low-defect laser powder bed melting and forming of noble metals, comprising the following steps: A precious metal powder is provided, and low-defect forming parameters are obtained according to the determination method described in the above technical solution; the precious metal component is formed by laser powder bed melting method according to the low-defect forming parameters.

[0034] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0035] In this invention, the precious metal powder is preferably pure platinum powder, and the particle size range of the precious metal powder is 10~53 μm.

[0036] In this invention, the precious metal powder is preferably pure platinum powder, and when the laser wavelength λ of the laser powder bed melting equipment is preferably 1070 nm, the low-defect forming parameters include: laser power of 160~240 W (most preferably 220 W), scanning spacing of 0.095 mm, powder layer thickness of precious metal powder of 0.020 mm, and scanning speed of 470~750 mm / s.

[0037] In this invention, the method for forming a low-defect laser powder bed of noble metals preferably includes the following steps: Step 1: Obtaining precious metal powder and its optical absorption parameters Precious metal powder is selected as the printing material, including platinum group metals, preferably pure platinum powder. The absorbance of the powder at the laser wavelength λ of a laser powder bed melting device is measured or obtained. η λ .

[0038] For pure platinum powder, when the laser wavelength of the device is 1070 nm, the powder absorption rate is η. λ = 0.2963.

[0039] Step 2: Establish an effective absorption volumetric energy density index According to laser power P Laser scanning rate v Scanning Spacing h and the thickness of the powder layer t Calculate the nominal volumetric energy density: Further introduce the powder absorption rate η λ By correcting the nominal volumetric energy density, we obtain the absorbed energy density: ;in, E abs This represents the actual energy absorbed per unit volume of the material.

[0040] Step 3: Establish the effective absorption volumetric energy window for low defects By printing dense samples, density testing, CT defect analysis, microstructure analysis, and / or single-pass cladding analysis, the low defect absorption energy window of noble metal materials can be obtained, enabling... satisfy: ;in, E lowTo avoid the lower limit of insufficient melting and lack of fusion defects, E high The upper limit is set to avoid overheating, deep melting, keyhole voids, and spatter defects.

[0041] For pure platinum powder, under 1070 nm laser conditions, The preferred low-defect absorption energy window is: 48≤ E abs ≤73 J / mm 3 ; The preferred center of the window is: E abs ∗ ≈ 59 J / mm 3 ; The corresponding nominal volumetric energy density window is: 162≤ VED ≤246 J / mm 3 ; The preferred center of the window is: VED∗ ≈ 200 J / mm 3 Step 4: Calculate the printing parameters based on the effective absorption volume energy window. Given the absorption rate of noble metal powder η λ Laser power P Scanning Spacing h and the thickness of the powder layer t In this case, the scanning speed is determined by the following formula: When using the window center value, the recommended scan speed is: ; When using a window range, the recommended scan speed range is: ; For pure platinum powder, when η λ = 0.2963、 h = 0.095 mm t When the radius is 0.020 mm, the recommended laser power range is: P = 160~240 W, with a recommended window center of approximately 220 W; the recommended scanning speed range is 470~750 mm / s, with a recommended window center of approximately 580 mm / s.

[0042] Step 5: Perform laser powder bed melting and forming In an inert atmosphere, noble metal powder is layered and laser-scanned to form dense or complex three-dimensional components. During the printing process, the laser power, laser scanning rate, scanning spacing, and powder layer thickness should meet the absorption energy density window determined in steps 3 and 4.

[0043] Step 6: Fabrication of noble metal lattice components Based on the aforementioned low-defect process window, noble metal lattice components were designed and fabricated.

[0044] This invention provides a precious metal component, which is prepared by the precious metal low-defect laser powder bed melting forming method described in the above technical solution.

[0045] In this invention, the precious metal component is preferably a pure platinum dense component or a target material. The CT-calculated relative density of the pure platinum dense component is preferably not less than 99%.

[0046] In this invention, the noble metal component is preferably a lattice component, a porous component, a thin-walled component, a curved surface component, or a complex three-dimensional component with internally connected channels. The lattice component preferably includes a three-period minimal surface (TPMS) structure, a crystal structure, a porous structure, or a continuous curved surface structure. More preferably, the lattice component is a three-period minimal surface (TPMS) structure. The TPMS structure is preferably a diamond-type structure. Even more preferably, the lattice component is a TPMS Diamond structure.

[0047] In this invention, the cell size of the lattice component is preferably 0.5~2.0 mm, more preferably 1~2 mm. The relative density of the lattice component is preferably 30%~70%. The wall thickness of the lattice component is preferably 0.12~0.60 mm, more preferably 0.15~0.60 mm. In this invention, the lattice component preferably comprises an integrally formed main body structure and a connecting structure. In this invention, for structures with smaller cell sizes and lower wall thicknesses, printability can be improved by increasing the wall thickness, increasing the cell size, adjusting the relative density, or optimizing the toner removal channel.

[0048] The present invention provides the application of the precious metal components described above in catalytic components, electrochemical components, high-temperature corrosion-resistant components, lightweight precious metal structural components, or complex precious metal functional components.

[0049] To further illustrate the present invention, the technical solutions provided by the present invention are described in detail below with reference to embodiments, but these should not be construed as limiting the scope of protection of the present invention. The following embodiments are based on... Figure 1 The flowchart shown is for a method of low-defect laser powder bed melting forming of precious metals.

[0050] Example 1 Pure platinum powder was used as the raw material, with a particle size ranging from 10 to 53 μm. The laser powder bed melting equipment employed a 1070 nm fiber laser, and the pure platinum powder layer thickness was 20 μm. At this wavelength, the absorption rate of the pure platinum powder was... η λ It is 0.2963.

[0051] The laser power was set to 220 W, the laser scanning rate to 635 mm / s, the scanning spacing to 0.095 mm, and the powder layer thickness to 0.020 mm. These parameters were used to print a pure platinum sample with dimensions of 4 × 2 × 2 mm.

[0052] Example 2 The difference from Example 1 is that the laser scanning rate is 580 mm / s.

[0053] Example 3 Based on the low-defect process window determined in Example 1, a TPMS Diamond lattice structure was designed. The lattice dimensions are 4×2×2 mm, the cell size is 1.0 mm, the relative density is 50%, and the wall thickness is 0.21 mm.

[0054] The difference from Example 1 is that the laser power is 200 W.

[0055] Example 4 The difference from Examples 1 and 3 is that the laser power is 160 W, the laser scanning rate is 750 mm / s, the scanning spacing is 0.045 mm, the cell size is 0.5 mm, the relative density is 70%, and the wall thickness is 0.15 mm.

[0056] Comparative Example 1 The difference from Example 1 is that the laser scanning rate is 360 mm / s.

[0057] Comparative Example 2 The difference from Example 1 is that the laser power is 350 W, the laser scanning rate is 200 mm / s, and the scanning interval is 0.120 mm.

[0058] Comparative Example 3 The difference from Example 4 is that the lattice structure has a relative density of 30% and a wall thickness of 0.06 mm. Figure 3 It can be seen that the relative density of the unit cell prepared in Comparative Example 3 is too low and the wall thickness is too small, so the component cannot be formed.

[0059] Test case Figure 2 These are physical images of laser powder bed melting (LPBF) formed samples of pure platinum solid components in Examples 1, 2, Comparative Examples 1 and 2 of this invention. Figure 3 These are physical images of the laser powder bed melting (LPBF) formed samples of pure platinum lattice components in Examples 3, 4 and Comparative Example 3 of this invention. Figures 4-5This is a CT scan 3D overall pore distribution map and pore volume distribution map of Embodiment 1 of the present invention. Figures 6-7 This is a CT scan 3D overall pore distribution map and pore volume distribution map of Comparative Example 1 of the present invention.

[0060] Table 1. Forming of pure platinum solid components under the conditions of Examples 1-2 and Comparative Examples 1-2

[0061] Table 2. Forming of pure platinum lattice components under the conditions of Examples 3-4 and Comparative Example 3.

[0062] Note: The relative density control in Table 2 is designed by software. The corresponding density can be obtained by printing directly according to the relative density control design parameters.

[0063] In summary, in the laser powder bed melting (LPBF) forming process of pure platinum solid components under 1070 nm laser conditions, strict control of energy input parameters is necessary to achieve low-defect, high-density formed parts. This invention demonstrates that pure platinum powder exhibits low-defect effective absorption volumetric energy (VBOE) under 1070 nm laser conditions. E abs ) Window size 48≤ E abs ≤73 J / mm 3 The corresponding nominal volumetric energy density ( VED ) Window size 162≤ VED ≤246 J / mm 3 Regarding the specific process parameter settings, when the platinum powder absorption rate... η λ =0.2963, scanning interval h =0.095 mm, powder layer thickness t When the diameter is 0.020 mm, it is recommended to control the laser power within the range of 160~240 W, with the optimal laser power being approximately [missing value]. P =220 W; it is recommended to control the laser scanning rate within the range of 470~750 mm / s, with the optimal laser scanning rate being approximately 580 mm / s. Using the above optimized parameter window for printing pure platinum samples can effectively ensure the quality and density of the formed parts.

[0064] In the laser powder bed fusion (LPBF) forming process of lattice platinum components, the geometric characteristics of the lattice structure have a significant impact on the forming quality. When using a small cell size (e.g., 0.5 mm) and a relative density set to 30% or 50%, the structure wall thickness is too thin, often making it difficult to maintain stability during the forming process or even preventing forming altogether. Conversely, as the cell size or wall thickness increases, the forming clarity and dimensional fidelity of the lattice structure are effectively improved. Considering both printability and structural integrity, it is recommended to prioritize the diamond topology (TPMS Diamond structure) within the three-period minimal surface (TPMS) family, with a cell size of 1.0–2.0 mm and a relative density of 50%–70%. Printing within this parameter range can better ensure the forming quality and mechanical properties of the lattice platinum components.

[0065] As can be seen from the above embodiments, the present invention provides a method for low-defect laser powder bed melting and forming of noble metals based on an effective absorption volume energy density window, and its complex components. This method first obtains the absorption rate of the noble metal powder at the laser wavelength, and then... The nominal process parameters are converted into effective absorbed volumetric energy density; subsequently, the laser power, scanning speed, scanning spacing, and powder layer thickness are determined based on the effective absorbed volumetric energy window for low defects, thus achieving low-defect forming of noble metals. For pure platinum powder, under 1070 nm laser conditions, the preferred effective absorbed volumetric energy window is 48~73 J / mm. 3 The center of the window is approximately 59 J / mm. 3 This invention further utilizes this process window to fabricate precious metal lattice components such as TPMS. This method can reduce incomplete fusion holes, keyholes, and thermal instability defects during precious metal printing, and enables the transferable fabrication of dense components and complex lattice components.

[0066] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for determining low-defect forming parameters for noble metal laser powder bed melting, characterized in that, The low-defect forming parameters include: laser power, scanning speed, scanning spacing, and the thickness of the noble metal powder layer; the method includes the following steps: Determine or obtain the absorption rate of precious metal powder under the laser wavelength λ of a laser powder bed melting device. Establish an effective absorbed volumetric energy density index for precious metal powders, wherein the effective absorbed volumetric energy density index is the actual absorbed energy per unit volume, and the calculation formula for the actual absorbed energy per unit volume is as shown in formula (1): Formula (1); In formula (1): This represents the actual energy absorbed per unit volume. The absorption rate of precious metal powder under the laser wavelength λ in a laser powder bed melting device. P is Laser power, For laser scanning rate, h For scanning spacing, t The thickness of the powder layer for precious metal powder; Based on the low-defect effective absorption volume energy window of noble metal powder In order to satisfy Under the given conditions, the low-defect forming parameters are determined according to formula (1); E low To avoid defects such as insufficient melting and / or lack of fusion, the lower limit of the actual energy absorbed per unit volume of precious metal powder is determined. E high To avoid any of the defects such as overheating, deep melting, keyholes, and spattering, the upper limit of the actual energy absorbed per unit volume of precious metal powder.

2. The determination method according to claim 1, characterized in that, The precious metal powder is a platinum group metal; the platinum group metal includes at least one of Ru, Rh, Pd, Os, Ir and Pt.

3. The determination method according to claim 1, characterized in that, The precious metal powder is pure platinum powder; when the laser wavelength λ of the laser powder bed melting equipment is 1070 nm, the absorption rate of the pure platinum powder is... It is 0.2963.

4. The determination method according to claim 1, characterized in that, The precious metal powder is pure platinum powder; the pure platinum powder has a low-defect effective absorption volumetric energy window. 48~73 J / mm 3 .

5. The determination method according to claim 1, characterized in that, The low-defect effective absorption volume energy window of the pure platinum powder The center value is 59 J / mm 3 In order to satisfy Equal to the low-defect effective absorption volume energy window Under the condition of the center value, the low-defect forming parameters of pure platinum powder are determined according to formula (1).

6. A method for forming a low-defect laser powder bed of precious metals, characterized in that, Includes the following steps: A precious metal powder is provided, and low-defect forming parameters are obtained according to the determination method described in claims 1 to 5; the precious metal component is formed by laser powder bed melting according to the low-defect forming parameters.

7. The method for forming low-defect laser powder bed fusion of noble metals according to claim 6, characterized in that, The precious metal powder is pure platinum powder, and when the laser wavelength λ of the laser powder bed melting equipment is 1070 nm, the low-defect forming parameters include: laser power of 160~240 W, scanning spacing of 0.095 mm, powder layer thickness of precious metal powder of 0.020 mm, and scanning speed of 470~750 mm / s.

8. A precious metal component, characterized in that, The noble metal component is prepared by the noble metal low-defect laser powder bed melting forming method as described in claim 6 or 7.

9. The precious metal component according to claim 8, characterized in that, The precious metal component is a pure platinum dense component or a target material, and the CT-calculated relative density of the pure platinum dense component is not less than 99%.

10. The precious metal component according to claim 8, characterized in that, The precious metal components include lattice components, porous components, thin-walled components, curved surface components, or complex three-dimensional components with internal interconnected channels.

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