Laser powder bed melting (LPBF) Mar-M247 alloy forming method for reducing cost

Abstract

The invention provides a laser powder bed melting (LPBF) Mar-M247 alloy forming method for reducing cost, and belongs to the technical field of metal additive manufacturing. The method aims at solving the technical problems that in the prior art, when Mar-M247 alloy is formed, a process window is narrow, and cracks and air holes are likely to be generated. The method comprises the steps that a substrate used for forming is preheated, and the temperature of the substrate is made to reach 120 DEG C to 150 DEG C; under the protection of inert atmosphere, Mar-M247 alloy powder is laid on the substrate layer by layer; and laser scanning is carried out on the alloy powder by cooperatively regulating and controlling the laser power, the scanning speed and the scanning interval, so that the energy density in the forming process is 55.28 J / mm < 3 >-73.2 J / mm < 3 >. According to the method, through combination of base plate preheating and precise energy density control, cracks and air holes in the forming process are effectively restrained, a high-quality formed part with the density higher than 99.9% can be stably obtained, the mechanical property of the high-quality formed part is superior to that of a traditional casting part, and a stable and reliable technical basis is provided for industrial additive manufacturing of the alloy.

Description

Technical Field

[0001] This application relates to the field of metal additive manufacturing technology, and in particular to a laser powder bed melting (LPBF) method for forming Mar-M247 alloy for cost reduction. Background Technology

[0002] Mar-M247 is a precipitation-strengthened nickel-based superalloy with excellent high-temperature strength, creep resistance, and hot corrosion resistance, making it a promising candidate for use in key hot-end components such as turbine blades in aero-engines. Laser powder bed melting, as an advanced additive manufacturing technology, enables the integrated, near-net-shape forming of such complex structural components, providing a new avenue for the application of Mar-M247 alloy.

[0003] However, Mar-M247 alloy is a highly crack-sensitive material. Under the extremely rapid heating and cooling rates of laser powder bed melting technology, enormous thermal stress is easily generated inside the formed part, inducing defects such as metallurgical cracks and porosity, resulting in unstable forming quality and severely restricting its engineering applications. Existing technologies have attempted to prepare Mar-M247 alloy using selective laser melting (SLM) technology and proposed optimizing process parameters to obtain high-density parts. However, these existing technologies have failed to provide a stable and reliable process window. For highly crack-sensitive alloys like Mar-M247, even small fluctuations in process parameters can lead to severe cracking or porosity defects, resulting in unstable forming quality. Furthermore, existing technologies have not revealed the precise correspondence between powder bed thickness, energy input, and final forming quality, making it difficult to balance production efficiency and cost control. To address these issues, the industry typically employs alloying modification with added alloying elements or expensive hot isostatic pressing (HIP) post-treatment, but this significantly increases manufacturing costs and process cycles, limiting the widespread application of this technology. Summary of the Invention

[0004] The purpose of this application is to provide a laser powder bed melting (LPBF) method for forming Mar-M247 alloy to reduce costs. It aims to solve the technical problems of narrow process window, unstable forming quality, easy cracking and porosity, and difficulty in balancing high quality and low cost when forming Mar-M247 alloy using laser powder bed melting technology in the prior art.

[0005] To achieve the above objectives, this application provides a cost-reducing laser powder bed melting (LPBF) method for forming Mar-M247 alloy, comprising the following steps: preheating a substrate for forming to a temperature of 120°C to 150°C; layering Mar-M247 alloy powder onto the substrate under an inert atmosphere; and performing laser scanning on the Mar-M247 alloy powder by coordinating and controlling the laser power, scanning speed, and scanning spacing to achieve a volume energy density of 55.28 J / mm² during the forming process. 3 Up to 73.2 J / mm 3 .

[0006] Optionally, the temperature of the substrate reaches 150°C.

[0007] Furthermore, the powder layer thickness is 30 μm; and the volume energy density is 68.97 J / mm². 3 Up to 73.2 J / mm 3 .

[0008] Furthermore, the laser power is 162W, the scanning speed is 827 mm / s, and the scanning interval is 0.09mm.

[0009] Furthermore, the powder layer thickness is 40 μm; and the volume energy density is 55.28 J / mm². 3 Up to 68.97 J / mm 3 .

[0010] Furthermore, the laser power is 185W, the scanning speed is 908 mm / s, and the scanning interval is 0.07mm.

[0011] Optionally, the Mar-M247 alloy powder is a spherical gas-atomized powder with a particle size distribution of 15-53 μm.

[0012] Optionally, the inert atmosphere is argon.

[0013] Furthermore, according to the method of claim 3, the Mar-M247 alloy powder is a spherical gas-atomized powder with a particle size distribution of 15-53 μm; and the inert atmosphere is argon.

[0014] Furthermore, according to the method of claim 5, the Mar-M247 alloy powder is a spherical gas-atomized powder with a particle size distribution of 15-53 μm; and the inert atmosphere is argon.

[0015] Compared with the prior art, the technical solution provided in this application has the following beneficial effects: 1. Significantly improves forming quality. By moderately preheating the substrate and precisely controlling the bulk energy density within a specific optimized range based on the powder layer thickness, the synergistic effect of these two measures effectively reduces the thermal stress gradient during the forming process and suppresses the crack sensitivity of the Mar-M247 alloy, thereby significantly reducing cracks and porosity defects and enabling the density of the formed parts to stably reach over 99.9%.

[0016] 2. Improve production efficiency and reduce costs. This method optimizes parameters to support efficient production with a larger powder layer thickness, which can significantly shorten the forming cycle. At the same time, due to the high quality of the formed parts, expensive post-processing steps such as hot isostatic pressing are reduced or avoided, thereby significantly reducing manufacturing costs.

[0017] 3. Ensuring excellent mechanical properties: The molded parts prepared by this method have better yield strength, tensile strength and elongation at room temperature than the traditional cast Mar-M247 alloy, achieving a balance between efficiency, cost and performance.

[0018] 4. Providing a stable process window, this invention clarifies the optimized volume energy density range for achieving high-quality forming under different layer thicknesses, providing a stable and reliable technical foundation for the industrialization and low-cost additive manufacturing of complex Mar-M247 alloy components. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic flow diagram of a laser powder bed melting (LPBF) Mar-M247 alloy forming method for reducing costs, provided for embodiments of this application; Figure 2 This is a schematic diagram showing the results of process parameter optimization when the powder layer thickness is 30 μm in an embodiment of this application; Figure 3 This is a schematic diagram showing the results of process parameter optimization when the powder layer thickness is 40 μm in an embodiment of this application; Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments. It is understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0022] Example 1: This embodiment provides a cost-reducing laser powder bed melting (LPBF) forming method for Mar-M247 alloy, aiming to achieve high-quality, high-density forming with a powder bed thickness of 30 μm through precise process control. Please refer to... Figure 1 The figure shows a schematic diagram of the overall process of the method provided in the embodiments of this application. The forming method mainly includes: powder preparation and equipment setting step S101, substrate preheating step S102, setting powder layer thickness step S103, coordinating and controlling laser parameters to control volume energy density step S104, layer-by-layer scanning forming step S105, and finally obtaining a high-quality formed part step S106.

[0023] Specifically, the detailed execution process of this embodiment is as follows: Step S101 involves powder preparation and equipment setup. In this embodiment, the raw material selected is Mar-M247 nickel-based superalloy powder. To ensure good flowability of the powder during the powder spreading process, high absorption rate during melting, and good packing density, spherical powder prepared by gas atomization is preferred. It should be noted that the particle size distribution of the powder has a significant impact on the forming quality. Powder that is too coarse is not easy to melt completely, while powder that is too fine has poor flowability and is prone to agglomeration. Therefore, this embodiment selects Mar-M247 alloy powder with a particle size distribution of 15-53 μm. This particle size range ensures that the powder layer has suitable porosity and good laser absorption characteristics. The forming equipment can be a commercial laser powder bed melting device, such as the M290 model from EOS GmbH, Germany. Before forming begins, the forming chamber of the equipment needs to be purified by vacuuming and repeatedly refilling with high-purity protective gas to control the oxygen content in the forming chamber to an extremely low level, for example, below 0.1%. In one specific implementation of this application, argon is chosen as the inert atmosphere because argon is stable, does not easily react with high-temperature molten metal, and is relatively cost-effective. It can effectively prevent active elements (such as aluminum and titanium) in Mar-M247 alloy from being oxidized at high temperatures, thereby ensuring the purity of the chemical composition and the excellent microstructure of the formed parts.

[0024] Step S102 involves preheating the substrate. Due to its high strength and complex phase structure, the Mar-M247 alloy exhibits extremely high crack sensitivity during the rapid solidification process of laser powder bed melting. This is primarily because a significant temperature gradient exists between the laser scanning area and the surrounding solidified area, resulting in substantial thermal stress. When this thermal stress exceeds the material's yield strength at high temperatures, solidification cracks will occur. To effectively mitigate this problem, this embodiment preheats the substrate before powder laying and laser scanning. Specifically, the equipment's built-in substrate heating system is activated to heat the substrate to 150°C, and this temperature is maintained constant throughout the forming process. Preheating the substrate to 150°C significantly reduces the temperature gradient between the molten pool and the formed portion, thereby reducing thermal stress and effectively suppressing crack initiation and propagation. It is understood that this preheating temperature is a preferred point, providing significant stress reduction without being too high and causing powder sintering or affecting the normal operation of the equipment.

[0025] Step S103 involves setting the powder layer thickness. The powder layer thickness is one of the key parameters affecting forming efficiency and forming quality. In this embodiment, the powder layer thickness is set to 30 μm. This is a relatively thin layer thickness, which is beneficial for achieving fine structures and high-quality surfaces, but it also places higher demands on the precise control of energy input.

[0026] Step S104 involves synergistically controlling laser parameters to manage the bulk energy density. Bulk energy density is a comprehensive process parameter characterizing the laser energy absorbed per unit volume of powder, and its calculation formula is as follows: Where E is the volume energy density (unit: J / mm²) 3 P represents laser power (W), v represents scanning speed (mm / s), h represents scanning spacing (mm), and t represents powder layer thickness (mm). The volume energy density directly determines the melting state of the powder, the size and stability of the molten pool, and is the core factor in controlling forming defects.

[0027] In this embodiment, for a powder layer thickness of 30 μm, an optimized bulk energy density range of 68.97 J / mm was discovered through extensive process experiments. 3 Up to 73.2 J / mm 3 When the volume energy density falls within this range, the formed part with the highest density and fewest defects can be obtained. To achieve this optimized volume energy density, this embodiment sets a preferred set of laser process parameters: laser power P is 162W, scanning speed v is 827 mm / s, and scanning spacing h is 0.09 mm. The volume energy density is calculated according to the above formula. This value falls precisely within the aforementioned optimized volume energy density range (68.97 J / mm).3 Up to 73.2 J / mm 3 )Inside.

[0028] Please see Figure 2 The figure is a schematic diagram of the optimization results of process parameters when the powder layer thickness is 30μm. (a) is a data diagram of process parameters of LPBF Mar-M247 alloy with a layer thickness of 30μm (the measured optimal parameters are marked in red); (b) is a light microscope image of the optimal parameters. Figure 2 The data typically includes a data table and metallographic microscope images. The data table clearly shows the volume energy density values ​​and their corresponding porosity of the formed parts under multiple sets of different parameter combinations. From the data, it can be observed that when the volume energy density is below 68.97 J / mm²... 3 At that time, due to insufficient energy input, the powder failed to melt completely, resulting in numerous irregular unfused voids inside the formed part, leading to a lower density. Correspondingly, when the bulk energy density exceeds 73.2 J / mm², 3 At this point, excessively high energy input causes the molten pool to overheat and become less stable, easily leading to the "keyhole" effect and the formation of spherical pores. Simultaneously, intense evaporation and splashing can also entrain gases, forming pores. Metallurgical microscope images visually confirm this pattern; only when the volume energy density is at 68.97 J / mm²... 3 Up to 73.2 J / mm 3 Within the optimized range, the microstructure of the formed part is most dense, with almost no observable porosity or crack defects. This embodiment uses 72.5 J / mm². 3 The volume energy density is precisely the best practice point within this optimization range.

[0029] Step S105 is layer-by-layer scanning forming. After setting all parameters, the automatic forming program of the equipment is started. First, the powder spreading mechanism (e.g., a soft scraper or roller) uniformly spreads a 30 μm thick layer of Mar-M247 alloy powder on the preheated substrate. Then, the laser scans the area to be formed in the current layer at a speed of 827 mm / s and a spacing of 0.09 mm, according to a preset power (162 W) and scanning strategy (e.g., strip scanning with 67° interlayer rotation). Wherever the laser beam reaches, the powder rapidly melts to form a tiny molten pool, achieving good metallurgical bonding with the solidified substrate below or the previous layer material. After one layer is scanned, the forming stage descends by one layer thickness (30 μm), the powder spreading mechanism spreads a new layer of powder, and the laser continues to scan the cross-section of the next layer. This process is repeated until all layers of the entire component have been processed.

[0030] Step S106 is to obtain a high-quality molded part. After the molding process is completed and the equipment cools to a safe temperature, the substrate with the molded part is removed from the molding chamber. The molded part is separated from the substrate by wire cutting or other methods, and the unmelted powder adhering to the surface is cleaned off. Testing shows that the Mar-M247 alloy molded part prepared by the method of this embodiment has a stable density of over 99.9%, with a specific measurement value of 99.96%, and no obvious internal cracks or porosity defects.

[0031] The sample prepared in this embodiment was subjected to room temperature tensile property testing, yielding a yield strength of 927±1.2 MPa, a tensile strength of 1107.3±1.2 MPa, and an elongation of 7.2±0.2%. Compared with the typical properties of conventional cast Mar-M247 alloy (e.g., yield strength of approximately 800 MPa, tensile strength of approximately 1000 MPa, and elongation of approximately 5.0%), the formed part prepared in this embodiment exhibits significant advantages in both strength and plasticity. This result demonstrates that this method not only solves the forming defect problem but also yields a material with excellent properties.

[0032] Example 2: This embodiment aims to provide a laser powder bed melting forming method for Mar-M247 alloy that further improves production efficiency while ensuring high-quality forming. As an optional implementation, an effective way to improve production efficiency is to increase the powder bed thickness. This means that when forming components of the same height, the total number of layers required is reduced, thereby shortening the total processing time. In this embodiment, the powder bed thickness is increased to 40 μm, and the process parameters are adjusted accordingly.

[0033] This embodiment also follows Figure 1 The overall process is shown below.

[0034] In step S101, the Mar-M247 alloy powder (spherical, 15-53 μm), forming equipment (such as EOSM290), and protective atmosphere (argon) used are the same as in Example 1.

[0035] In step S102, the substrate is also preheated and kept at a constant temperature of 150°C. Understandably, this step is also crucial for suppressing thermal cracking during the forming process of large-layer-thickness substrates.

[0036] In step S103, the powder layer thickness in this embodiment is set to 40 μm, which is about 33% thicker than the 30 μm in Example 1.

[0037] The key to this embodiment lies in the coordinated control of laser parameters in step S104. As the powder layer thickness increases, the volume of powder that needs to be melted in a single layer also increases. If the high volume energy density of Example 1 is still used, it may lead to excessive energy accumulation, resulting in an excessively large and unstable molten pool, which could easily cause new defects. Therefore, a new and more suitable volume energy density range needs to be matched to the 40 μm powder layer thickness. Experimental studies have shown that when the powder layer thickness is 40 μm, the optimized volume energy density range is 55.28 J / mm². 3 Up to 68.97 J / mm 3 .

[0038] To achieve the energy input within this optimized range, this embodiment sets a new set of laser process parameters: laser power P = 185W, scanning speed v = 908 mm / s, and scanning spacing h = 0.074 mm. Based on these parameters, the volume energy density is calculated. This value is very close to the optimization range (55.28 J / mm). 3 Up to 68.97 J / mm 3 The upper limit of the laser energy ensures that, even with a large layer thickness, the laser energy is sufficient to completely melt through the 40μm powder layer and form a good fusion with the underlying layer.

[0039] Please see Figure 3 This figure illustrates the optimized process parameters for a powder-coated layer thickness of 40 μm. (a) shows the process parameters for a 40 μm thick LPBF Mar-M247 alloy (the measured optimal parameters are marked in red); (b) shows the optical micrograph of the optimal parameters. Figure 2 similar, Figure 3 The data and images show that, for a layer thickness of 40 μm, using 55.28 J / mm 3 Up to 68.97 J / mm 3 The high volumetric energy density effectively balances melting depth and molten pool stability, thereby suppressing crack and porosity formation. The parameter combination used in this embodiment is the optimal solution within this process window.

[0040] In step S105, the equipment manufactures layer by layer according to the parameters set in this embodiment (layer thickness 40 μm, power 185 W, speed 908 mm / s, spacing 0.07 mm). Due to the increased layer thickness, the number of layers required to complete a component of the same height is reduced by 25% compared to Embodiment 1, significantly shortening the forming time. Calculations show that the overall production efficiency is increased by approximately 30%.

[0041] In step S106, the final formed part was tested and found to have a density of up to 99.94%, effectively suppressing macroscopic cracks and internal porosity defects. This demonstrates the effectiveness of the core idea proposed in this application: "matching a specific optimized volumetric energy density range according to the powder layer thickness."

[0042] More noteworthy are its mechanical properties. Room temperature tensile tests were conducted on the samples prepared in this embodiment, revealing a yield strength of 943±5.4 MPa, a tensile strength of 1239±6.9 MPa, and an elongation of 8±0.6%. It should be noted that these mechanical property values ​​are not only significantly superior to those of traditional castings, but also slightly higher in both strength and plasticity than the samples prepared in Example 1 (30μm layer thickness). This indicates that the method described in this embodiment not only achieves a substantial increase in production efficiency and a reduction in cost (reducing post-processing requirements and time costs by approximately 25%), but also yields molded parts with superior performance, achieving a good balance between efficiency, cost, and performance.

[0043] Example 3: This embodiment aims to further verify the optimized volume energy density range (68.97 J / mm²) proposed in Example 1 for a powder layer thickness of 30 μm. 3 Up to 73.2 J / mm 3 The aim is to demonstrate the universality and reliability of the technology. In other words, it aims to prove that within this range, it is not only the specific combination of laser power, scanning speed, and scanning spacing in Example 1 that yields excellent results, but rather that there exists a process window in which high-quality forming can be achieved through different combinations of parameters, as long as the volume energy density falls within this range.

[0044] The process flow in this embodiment is basically the same as that in Embodiment 1, and also follows the same principles. Figure 1 The steps are shown.

[0045] The powder preparation and equipment setup steps S101, the substrate preheating step S102 (preheating to 150°C), and the powder layer thickness setting step S103 (setting to 30μm) are exactly the same as in Example 1.

[0046] In step S104, this embodiment uses a set of laser process parameters different from those in Embodiment 1. Specifically, the laser power P is 200W, the scanning speed v is 952 mm / s, and the scanning spacing h is 0.10 mm. Based on the volume energy density formula, As can be seen, the volumetric energy density value is 70.0 J / mm². 3 Although obtained using a completely different set of P, v, and h parameters, it still stably falls within the optimization range verified in Example 1 (68.97 J / mm). 3 Up to 73.2 J / mm3 Within.

[0047] Subsequent steps S105 and S106 were performed according to the newly set parameters. The resulting molded part, after metallographic analysis and density testing, still maintained a density of over 99.9%, with a dense internal microstructure and very few defects. Its mechanical properties, after testing, showed no significant difference compared to the sample prepared in Example 1, and were also far superior to traditional castings.

[0048] The results of this embodiment strongly demonstrate that the core technical idea disclosed in this application—namely, determining an optimized volume energy density range for a specific powder layer thickness—is key to solving the forming problem of Mar-M247 alloy. Within this range, users can flexibly coordinate and adjust parameters such as laser power, scanning speed, and scanning spacing according to the characteristics and needs of their own equipment. As long as the final volume energy density is within this optimized range, high-quality forming results can be reproduced. This provides great convenience and reliability for the industrial application of this technology.

[0049] Example 4: This embodiment aims to verify the robustness of the method provided in this application under small fluctuations in process parameters, particularly the critical parameter of substrate preheating temperature. In the independent claims, the substrate preheating temperature is limited to a range of 120°C to 150°C. Embodiments 1, 2, and 3 all use the upper limit of this range, 150°C, as the preferred temperature. This embodiment will explore the case where molding is performed using the lower limit of this range.

[0050] The process flow of this embodiment is similar to that of Embodiment 2, and it mainly focuses on verifying the forming of a 40μm layer thickness.

[0051] In steps S101 and S103 (set to 40 μm), the materials, equipment, atmosphere, and layer thickness used are the same as in Example 2.

[0052] In step S102, in this embodiment, the substrate preheating temperature is set to 120°C, and the entire forming process is carried out at this constant temperature. Compared to 150°C, the preheating temperature of 120°C is slightly less effective in reducing thermal stress, but it still has a significant mitigating effect, while consuming less energy.

[0053] In step S104, considering that a decrease in preheating temperature may affect the stability of the molten pool, the laser parameters can be fine-tuned. In this embodiment, to ensure sufficient energy input to the molten pool to compensate for the lower ambient temperature, the laser parameters are set as follows: laser power P = 190W, scanning speed v = 908 mm / s, and scanning spacing h = 0.07 mm. The volume energy density can be calculated. .

[0054] It should be noted that the volumetric energy density value (71.2 J / mm²) 3 Although higher than the range optimized for a 40 μm layer thickness in Example 2 (55.28-68.97 J / mm), 3 However, it still falls within the broader overall energy density range defined in this application (55.28 J / mm²). 3 Up to 73.2 J / mm 3 This indicates that when preheating conditions change, the energy input can be appropriately adjusted within permissible limits to adapt to the new thermal environment and still achieve high-quality forming.

[0055] In subsequent forming and testing steps, the final formed part still achieved a density of over 99.9%, and no serious metallurgical defects such as through-cracks were found through metallographic observation. This result fully demonstrates that the technical solution proposed in this application has good process robustness. In other words, within a preheating temperature range of 120℃ to 150℃, by controlling the bulk energy density at 55.28 J / mm²... 3 Up to 73.2 J / mm 3 Within the specified range, the challenges of laser powder bed melting and forming of Mar-M247 alloy can be effectively solved.

[0056] In summary, the laser powder bed melting (LPBF) Mar-M247 alloy forming method provided in this application for cost reduction reduces the basic thermal stress by preheating the substrate to 120°C-150°C, and by coordinating and controlling the laser power, scanning speed, and scanning spacing according to the selected powder bed thickness (e.g., 30μm or 40μm), precisely controlling the bulk energy density within a matching optimized range (overall range of 55.28 J / mm²). 3 Up to 73.2 J / mm 3 This method effectively solves the defect control problem in the forming process of high crack-sensitive alloys such as Mar-M247. It not only reliably yields high-quality formed parts with a density exceeding 99.9% and mechanical properties superior to traditional castings, but also significantly improves production efficiency and reduces manufacturing costs by using larger layer thicknesses. This provides a stable, reliable, and economically viable technical approach for low-cost, industrialized additive manufacturing of complex components made from such high-performance alloys.

[0057] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for forming a laser powder bed fusion (LPBF) Mar-M247 alloy at reduced cost, the method comprising: The method comprises the following steps: preheating a substrate for forming to make the temperature of the substrate reach 120-150 ℃; laying Mar-M247 alloy powder on the substrate layer by layer under the protection of inert atmosphere; The laser scanning was performed on the Mar-M247 alloy powder by synergistically regulating the laser power, scanning speed and scanning interval, so that the bulk energy density in the forming process was 55.28 J / mm 3 to 73.2 J / mm 3 .

2. The method of claim 1, wherein, the temperature of the substrate reaches 150 ℃.

3. The method of claim 2, wherein, The powder layer thickness is 30 μm; and the bulk energy density is 68.97 J / mm 3 to 73.2 J / mm 3 .

4. The method of claim 3, wherein, The laser power is 162 W, the scanning speed is 827 mm / s, and the scanning interval is 0.09 mm.

5. The method of claim 2, wherein, The powder layer thickness is 40 μm; and the bulk energy density is 55.28 J / mm 3 to 68.97 J / mm 3 .

6. The method of claim 5, wherein, The laser power is 185 W, the scanning speed is 908 mm / s, and the scanning interval is 0.074 mm.

7. The method according to any one of claims 1 to 6, characterized in that, The Mar-M247 alloy powder is spherical gas-atomized powder, and the particle size distribution is 15-53 μm.

8. The method according to any one of claims 1 to 6, characterized in that, The inert atmosphere is argon.

Images