Nickel-based superalloy powder and single crystal additive manufacturing thereof

Abstract

The present disclosure relates to additive manufacturing of nickel-based superalloys, in particular to the manufacturing of single-crystal components of such nickel-based superalloys. By adjusting the alloy powder composition, shaping the laser beam and optimizing the process parameters, the successful production of dense, crack-free single-crystal microstructures of nickel-based superalloys is achieved.

Description

Technical Field

[0001] The present disclosure relates to the field of additive manufacturing, and more particularly to the additive manufacturing of nickel-based superalloy powders. Background Art

[0002] Powder-bed-based additive manufacturing (AM) technologies, such as laser powder bed fusion (PBF-LB), use lasers to melt and solidify metal powder layer by layer to create components with high precision and complex geometries. This technology offers numerous advantages in metal component production, including reduced material waste, shorter production cycles, and support for lightweight design. Consequently, it is widely used in the manufacture of high-performance components in aerospace, energy, and medical applications.

[0003] High-performance nickel-based high-temperature alloys (γ'-Ni3(Al,Ti) precipitation-strengthened types, such as classic grades Alloy713(K418), Alloy738, etc.) are widely used in the aerospace field due to their excellent high-temperature strength, corrosion resistance, and creep resistance. Especially in extreme working environments such as aircraft engines and gas turbines, the demand for the preparation of single-crystal components of this type of nickel-based high-temperature alloys is becoming more and more urgent. At present, single-crystal components are mainly manufactured by directional solidification technology, but this method has problems such as low yield, severe solidification segregation, long processing cycle, and low material utilization rate. It is also difficult to manufacture complex components, which limits its development. In contrast, PBF-LB technology can achieve near-net forming of complex components and has significant advantages, but it still faces some challenges:

[0004] 1. The high crack sensitivity (difficulty in welding) of γ'-Ni3(Al,Ti) precipitation-strengthened nickel-based superalloys, combined with the high residual stress inherent in additive manufacturing, makes crack suppression a major technical challenge in additive manufacturing of these superalloy components. Therefore, further research is needed to optimize their composition to reduce crack sensitivity and achieve effective crack suppression using PBF-LB technology.

[0005] 2. The existing PBF-LB technology generally uses a Gaussian laser beam with high energy distribution at the center and low energy at the edges in the manufacture of nickel-based high-temperature alloys. This easily causes a high-temperature gradient in the molten pool, resulting in melting characteristics such as deep melting and strong convection, which is not conducive to the preparation of single crystals. Diffractive optical elements (DOEs), as high-diffraction-efficiency optical elements based on diffraction optics theory, have been widely used in beam shaping technology by compensating the phase of the input beam to change the transmission characteristics and intensity of the beam. However, it is still impossible to prepare single crystals of nickel-based high-temperature alloys by beam shaping alone without optimizing process parameters (such as spot size and laser energy distribution).

[0006] 3. Existing beam shaping technologies struggle to achieve dynamic adjustment and lack the ability to freely switch between different spot shapes. In particular, they lack the ability to switch DOEs without disassembling the original optical path to reduce re-installation errors. This limitation limits the ability to achieve high-degree-of-freedom control of the melt heat flux vector, making it difficult to meet the requirements of single crystal preparation. Summary of the Invention

[0007] The present disclosure proposes a nickel-based high-temperature alloy powder and its additive manufacturing method and device, which successfully achieves the preparation of dense, crack-free nickel-based high-temperature alloy single crystal structure through composition optimization, beam shaping and process parameter regulation.

[0008] In a first aspect, the present disclosure provides an additively manufactured nickel-based high-temperature alloy component having the following grain boundary structure characteristics: within the grain boundary angle range of 15° to 30°, the grain boundary length density does not exceed 35.2 (1 / mm); within the grain boundary angle range of more than 30°, the grain boundary length density does not exceed 2.6 / (1 / mm).

[0009] In a second aspect, the present disclosure provides a powder for additive manufacturing of the nickel-based high-temperature alloy component described in the first aspect, wherein the composition of the powder comprises the following elements in weight percentage: chromium (Cr): 12wt% to 14wt%, molybdenum (Mo): 4.5wt% to 5.7wt%, niobium (Nb): 1.5wt% to 2.3wt%, aluminum (Al): 5.5wt% to 6.5wt%, titanium (Ti): 0.5wt% to 1wt%, carbon (C): 0.1wt% to 0.28wt%, zirconium (Zr): 0.02wt% to 0.1wt%, boron (B): ≤0.01wt%, silicon (Si): ≤0.5wt%, manganese (Mn): ≤0.25wt%, iron (Fe): ≤2.5wt%, copper (Cu): ≤0.5wt%, nickel (Ni): balance.

[0010] According to a preferred embodiment of the second aspect, the constituent elements of the powder include one or more of the following: C is selected as 0.1wt% to 0.19wt%, Mo is selected as 4.5wt% to 5.1wt%, B is selected as 0.001wt% to 0.01wt%, Zr is selected as 0.05wt% to 0.1wt%, and Nb is selected as 1.8wt% to 2.3wt%.

[0011] In a third aspect, the present disclosure provides a powder for additive manufacturing of the nickel-based high-temperature alloy component of the first aspect, wherein the composition of the powder comprises the following elements by weight percentage: chromium (Cr): 15.7 wt% to 16.3 wt%, aluminum (Al): 3.2 wt% to 3.7 wt%, titanium (Ti): 3.2 wt% to 3.7 wt%, molybdenum (Mo): 1.5 wt% to 2.5 wt%, niobium (Nb): 0.6 wt% to 1.4 wt%, zirconium (Zr): 0.02 wt% to 0. 1wt%, boron (B): 0.003wt% ~ 0.015wt%, carbon (C): 0.05wt% ~ 0.13wt%, tantalum (Ta): 1.5wt% ~ 2.3wt%, tungsten (W): 2.4wt% ~ 3.0wt%, cobalt (Co): 2.0wt% ~ 8.0wt%, iron (Fe): ≤0.05wt%, manganese (Mn): ≤0.02wt%, silicon (Si): ≤0.3wt%, sulfur (S): ≤0.015wt%, nickel (Ni): balance.

[0012] According to a preferred embodiment of the third aspect, the constituent elements of the powder include one or more of the following: molybdenum (Mo) is selected as 1.6wt% to 2.1wt%, niobium (Nb) is selected as 0.7wt% to 1.2wt%, carbon (C) is selected as 0.08wt% to 0.12wt%, tantalum (Ta) is selected as 1.6wt% to 2.1wt%, tungsten (W) is selected as 2.5wt% to 2.9wt%, zirconium (Zr) is selected as 0.02wt% to 0.07wt%, boron (B) is selected as 0.003wt% to 0.011wt%, and cobalt (Co) is selected as 2.0wt% to 6.0wt%.

[0013] According to a preferred embodiment of the third aspect, the content of aluminum + titanium (Al + Ti) is selected to be 6.5 wt % to 7.4 wt %.

[0014] In a fourth aspect, the present disclosure provides a method for additive manufacturing of a nickel-based high-temperature alloy single crystal component formed from powder according to any one of the second aspect or the third aspect, the method comprising: controlling a laser beam that is shaped by a diffraction optical element in the form of a flat-top spot at least during the additive manufacturing process according to a preset scanning path and process parameters, and selectively melting the powder layer by layer on a substrate to form stacked and consolidated layers until the manufacture of the single crystal component is completed.

[0015] According to a preferred embodiment of the fourth aspect, the process parameters include one or more of a laser power of 50 to 500 W, a laser scanning speed of 50 to 1500 mm / s, a scanning line spacing of 0.02 to 0.18 mm, a layer thickness of 40 to 60 μm, a spot diameter of 50 to 1000 μm, a ratio of the molten pool width to the molten pool depth of 2 to 5, a ratio of the molten pool width to the scanning line spacing of 2 to 5, and a ratio of the molten pool depth to the layer thickness of 1.1 to 3.

[0016] In a fifth aspect, the present disclosure provides a device for realizing the switching of the diffraction optical element in the method described in any one of the fourth aspects, wherein the device is constructed in the optical path before the laser beam enters the deflection mirror and is configured to include: a supporting portion, which is fixed in the optical path; a separating portion, which is detachably fixed to the supporting portion; and a mounting portion, which is fixed to the separating portion and is used to mount the diffraction optical element; wherein, when switching the diffraction optical element, the diffraction optical element is separated from the optical path by removing the separating portion from the supporting portion.

[0017] According to a preferred embodiment of the fifth aspect, the supporting portion is fixed between the beam expander and the deflection mirror in the optical path and is not disassembled when the diffractive optical element is switched.

[0018] According to a preferred embodiment of the fifth aspect, the mounting portion includes at least one displacement adjuster for adjusting the displacement of the diffractive optical element in the X-axis and / or Y-axis directions.

[0019] According to a preferred embodiment of the fifth aspect, the separation portion is embedded in the support portion so that the diffractive optical element is embedded in at least a portion of the groove of the support portion in the installed state.

[0020] In a sixth aspect, the present disclosure provides an additive manufacturing device comprising the apparatus described in any one of the fifth aspects.

[0021] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate one or more embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure and to enable one of ordinary skill in the relevant art to make and use the disclosure.

[0023] Figure 1 A schematic diagram of an additive manufacturing device according to an embodiment of the present disclosure is shown;

[0024] Figure 2shows a cross-sectional image of a nickel-based high-temperature alloy component specimen prepared according to Test Example 1 of the present disclosure;

[0025] Figure 3 The crystal orientation characterization results of the SEM-EBSD test on the cross section of the sample prepared according to Test Example 1 of the present disclosure are shown;

[0026] Figure 4 The crystal orientation characterization results of the SEM-EBSD test on the cross section of the sample prepared according to Test Example 2 of the present disclosure are shown;

[0027] Figure 5 A schematic diagram of the exploded structure of the DOE fast switching device in the optical path according to an embodiment of the present disclosure is shown;

[0028] Figure 6 A schematic diagram of the structure of the DOE fast switching device in use state in an optical path according to an embodiment of the present disclosure is shown;

[0029] Figure 7 A schematic diagram of the structure of a local use state of a DOE fast switching device in an optical path according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0030] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments may be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, the description of these embodiments is intended to make this disclosure more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a deeper understanding of the embodiments of the present disclosure.

[0031] Additive Manufacturing (AM), as described in this disclosure, is a 3D printing technology that creates components by gradually adding powdered material and then melting and solidifying it layer by layer using a laser beam. Based on a digital model generated by computer-aided design (CAD) software, this technology precisely controls the melting and solidification of each layer, gradually producing a complete component.

[0032] Nickel-based high-temperature alloy powder (Alloy713 (K418))

[0033] As previously described in the background section, nickel-based superalloys, especially gamma-prime precipitate strengthened high-performance nickel-based superalloys such as Alloy 713 (K418), are prone to significant cracking phenomena during PBF-LB processes due to the high inherent cracking susceptibility of the material and the high inherent residual stresses of the process. Therefore, a fine-tuned optimization of their composition is required to reduce the cracking susceptibility in order to effectively control and suppress crack formation in additive manufacturing. Some embodiments of the present disclosure are directed to the optimization of the composition of nickel-based superalloy powders, in particular to the composition optimization of hard-to-weld nickel-based superalloys such as the classic Alloy 713 (K418) to reduce the cracking susceptibility to achieve effective crack suppression of components in PBF-LB technology. The composition optimization of the present disclosure is mainly directed to an increase of the carbon (C) and molybdenum (Mo) content and a reduction of the boron (B), zirconium (Zr) and niobium (Nb) content.

[0034] (Pre-optimization)

[0035] The pre-optimized nickel-based superalloy powder composition generally comprises 12-14 wt% chromium (Cr), 3.8-5.2 wt% molybdenum (Mo), 1.8-2.8 wt% niobium (Nb), 5.5-6.5 wt% aluminum (Al), 0.5-1 wt% titanium (Ti), 0.08-0.2 wt% carbon (C), 0.05-0.15 wt% zirconium (Zr), 0.005-0.015 wt% boron (B), <0.5 wt% silicon (Si), <0.25 wt% manganese (Mn), <2.5 wt% iron (Fe), <0.5 wt% copper (Cu) and the balance nickel (Ni) by weight percentage.

[0036] In one example, the pre-optimized nickel-based superalloy powder composition comprises 13 wt% Cr, 4.5 wt% Mo, 2.3 wt% Nb, 6 wt% Al, 0.75 wt% Ti, 0.14 wt% C, 0.01 wt% B, 0.1 wt% Zr, 0.25 wt% Si, 0.125 wt% Mn, 1.25 wt% Fe, 0.25 wt% Cu and the balance Ni by weight percentage.

[0037] This composition design has already provided a good high-temperature strength and corrosion resistance, but during additive manufacturing, especially laser melting, its cracking tendency is still significant.

[0038] (Post-optimization)

[0039] Generally speaking, the optimized nickel-based high-temperature alloy powder composition includes, by weight percentage, 12wt% to 14wt% Cr, 4.5wt% to 5.7wt% Mo, 1.5wt% to 2.3wt% Nb, 5.5wt% to 6.5wt% Al, 0.5wt% to 1wt% Ti, 0.1wt% to 0.28wt% C, 0.02wt% to 0.1wt% Zr, ≤0.01wt% B, ≤0.5wt% Si, ≤0.25wt% Mn, ≤2.5wt% Fe, ≤0.5wt% Cu and the balance Ni.

[0040] In a preferred embodiment, the C, Mo, B, Zr, Nb or a combination thereof of the optimized nickel-based high-temperature alloy powder is selected to be 0.1wt% to 0.19wt% of C, 4.5wt% to 5.1wt% of Mo, 0.001wt% to 0.01wt% of B, 0.05wt% to 0.1wt% of Zr and 1.8wt% to 2.3wt% of Nb.

[0041] In one example, the optimized nickel-based high-temperature alloy powder composition includes, by weight percentage, 13wt% Cr, 5.1wt% Mo, 1.9wt% Nb, 6wt% Al, 0.75wt% Ti, 0.19wt% C, 0.005wt% B, 0.06wt% Zr, 0.25wt% Si, 0.125wt% Mn, 1.25wt% Fe, 0.25wt% Cu, and the balance Ni.

[0042] In one example, the optimized nickel-based high-temperature alloy powder composition includes, by weight percentage, 13wt% Cr, 4.8wt% Mo, 2.05wt% Nb, 6wt% Al, 0.75wt% Ti, 0.145wt% C, 0.0055wt% B, 0.075wt% Zr, 0.25wt% Si, 0.125wt% Mn, 1.25wt% Fe, 0.25wt% Cu, and the balance Ni.

[0043] In practice, the optimized nickel-based superalloy powder performed particularly well in PBF-LB, particularly in reducing cracking while maintaining overall material performance. This optimization not only involves adjusting a single element, but also controls the interactions between multiple elements to achieve comprehensive performance improvements.

[0044] C is a key element in the formation of carbides, which can effectively prevent slip at grain boundaries, thereby improving the material's high-temperature strength and creep resistance. In the optimized composition, a moderate increase in the C content (controlled within 0.1wt% to 0.28wt%, especially within 0.1wt% to 0.19wt%) not only improves the alloy's high-temperature mechanical properties, but also, to a certain extent, consumes solidification segregation elements at the grain boundaries through the formation of carbides, thereby reducing the material's cracking sensitivity. Mo, as a strong solid solution strengthening element, can not only improve the alloy's creep resistance, but also reduce the material's plastic deformation in the high-temperature range; at the same time, Mo is also a carbide-forming element. By appropriately increasing the Mo content (controlled within 4.5wt% to 5.7wt%, especially within 4.5wt% to 5.1wt%), not only the alloy's high-temperature mechanical properties are improved, but also the amount of carbide formation is optimized to reduce the material's cracking sensitivity.

[0045] B and Zr are usually used as grain boundary strengthening elements in alloys to improve the grain boundary strength and high-temperature performance of the material. However, excessive B and Zr will increase the cracking sensitivity of the alloy, especially in additive manufacturing, where higher B and Zr contents will trigger liquefaction cracking effects. During the optimization process, the cracking sensitivity of the alloy was significantly reduced by reducing the B content to ≤0.01wt% (especially controlling it to 0.001wt%~0.01wt%) and controlling the Zr content to 0.02wt%-0.1wt% (especially controlling it to 0.05wt%~0.1wt%). This reduction not only did not significantly affect the high-temperature performance of the alloy, but instead enabled it to suppress cracking during the PBF-LB process. Nb, as an important γ' strengthening phase stabilizing element, was also moderately reduced during the optimization process. Before optimization, the Nb content was between 1.8wt% and 2.8wt%, while after optimization, the Nb content was reduced to 1.5wt% to 2.3wt%, especially to 1.8wt% to 2.3wt%, which can reduce the solidification segregation of Nb and thus reduce the cracking sensitivity of the alloy.

[0046] By adjusting the above elements, the cracking sensitivity of nickel-based high-temperature alloys during the PBF-LB process has been significantly reduced, which is crucial for cracking suppression.

[0047] In addition, the nickel-based superalloy powder with optimized composition also meets the requirements for single crystal preparation. The optimized powder, combined with the PBF-LB process, including DOE beam shaping technology, can achieve precise shaping and control of the molten pool, and thus achieve dynamic single crystal selection, resulting in a single crystal structure with strong texture and no high-angle grain boundaries, or a near-single crystal structure with strong texture but a small amount of high-angle grain boundaries. Such single crystal / near-single crystal structure can maintain excellent mechanical properties (high strength and creep resistance) in high-temperature environments, and its single crystal / near-single crystal components are crucial in the hot end of aircraft engines and gas turbines.

[0048] Nickel-based high-temperature alloy powder (Alloy738)

[0049] Some embodiments of the present disclosure involve optimizing the composition of nickel-based superalloy powders, particularly those of difficult-to-weld nickel-based superalloys such as the classic Alloy 738, to reduce crack susceptibility and effectively suppress cracking in components using PBF-LB techniques. The composition optimization disclosed herein primarily involves increasing the contents of Mo, Nb, C, Ta, and W, and reducing the contents of boron, Zr, B, and Co.

[0050] (Before optimization)

[0051] Generally speaking, the composition of the nickel-based high-temperature alloy powder before optimization includes, by weight percentage, 15.7wt% to 16.3wt% Cr, 3.2wt% to 3.7wt% Al, 3.2wt% to 3.7wt% Ti, 1.5wt% to 2.0wt% Mo, 0.6wt% to 1.1wt% Nb, 0.05wt% to 0.15wt% Zr, 0.005wt% to 0.015wt% B, 0.15wt% to 0.2wt% C, 1.5wt% to 2.0wt% Ta, 2.4wt% to 2.8wt% W, 8.0wt% to 9.0wt% Co, ≤0.05wt% Fe, ≤0.02wt% Mn, ≤0.3wt% Si, ≤0.015wt% S and the balance Ni.

[0052] In one example, the nickel-based high-temperature alloy powder composition before optimization includes, by weight percentage, 16wt% Cr, 3.45wt% Al, 3.45wt% Ti, 1.75wt% Mo, 0.85wt% Nb, 0.1wt% Zr, 0.01wt% B, 0.175wt% C, 1.75wt% Ta, 2.6wt% W, 8.5wt% Co, 0.025wt% Fe, 0.01wt% Mn, 0.15wt% Si, 0.0075wt% S, and the balance Ni.

[0053] (After optimization)

[0054] Generally speaking, the optimized nickel-based high-temperature alloy powder composition includes, by weight percentage, 15.7wt% to 16.3wt% Cr, 3.2wt% to 3.7wt% Al, 3.2wt% to 3.7wt% Ti, 1.5wt% to 2.5wt% Mo, 0.6wt% to 1.4wt% Nb, 0.02wt% to 0.1wt% Zr, 0.003wt% to 0.015wt% B, 0.05wt% to 0.13wt% C, 1.5wt% to 2.3wt% Ta, 2.4wt% to 3.0wt% W, 2.0wt% to 8.0wt% Co, ≤0.05wt% Fe, ≤0.02wt% Mn, ≤0.3wt% Si, ≤0.015wt% S and the balance Ni.

[0055] In a preferred embodiment, the Mo, Nb, B, Zr, Nb or their combinations in the optimized nickel-based high-temperature alloy powder are selected to be 1.6wt% to 2.1wt% of Mo, 0.7wt% to 1.2wt% of Nb, 0.08wt% to 0.12wt% of C, 1.6wt% to 2.1wt% of Ta, 2.5wt% to 2.9wt% of W, 0.02wt% to 0.07wt% of Zr, 0.003wt% to 0.011wt% of B and 2.0wt% to 6.0wt% of Co.

[0056] In a preferred embodiment, the combination of aluminum and titanium (Al+Ti) is selected to be 6.5 wt% to 7.4 wt%.

[0057] In one example, the optimized nickel-based high-temperature alloy powder composition includes, by weight percentage, 16wt% Cr, 3.45wt% Al, 3.45wt% Ti, 2wt% Mo, 1wt% Nb, 0.06wt% Zr, 0.009wt% B, 0.09wt% C, 1.9wt% Ta, 2.7wt% W, 5wt% Co, 0.025wt% Fe, 0.01wt% Mn, 0.15wt% Si, 0.0075wt% S, and the balance Ni.

[0058] In the optimized composition, controlling the C content to 0.05wt% to 0.13wt%, particularly 0.08wt% to 0.12wt%, not only improves the alloy's high-temperature mechanical properties but also, to a certain extent, reduces the material's cracking susceptibility by consuming solidification segregation elements at grain boundaries through the formation of carbides. Mo, as a strong solid-solution strengthening element, not only improves the alloy's creep resistance but also reduces plastic deformation in the high-temperature range; Mo is also a carbide-forming element. By controlling the Mo content to 1.5wt% to 2.5wt%, particularly 1.6wt% to 2.1wt%, the material's high-temperature strength is effectively improved while reducing cracking susceptibility. Nb is a key element in the formation of the γ' strengthening phase, promoting its formation and stabilization in the alloy, thereby improving strength and hardness at high temperatures. However, excessive Nb content can lead to solidification segregation, increasing the risk of cracking. Therefore, after optimization, the Nb content is increased to 0.6wt% to 1.4wt%, and particularly preferably to 0.7wt% to 1.2wt%, in order to achieve a balance between strength and toughness and ensure that Alloy738 has good crack resistance during the PBF-LB process. Ta and W, as effective γ' strengthening phase elements, can further enhance the high-temperature strength and hardness of the alloy. Ta is increased to 1.5wt% to 2.3wt%, especially controlled at 1.6wt% to 2.1wt% in the preferred embodiment, while W is increased to 2.4wt% to 3.0wt%, preferably 2.5wt% to 2.9wt%, which can improve the material's resistance to high-temperature deformation and reduce the tendency to cracking caused by thermal cycling, so as to facilitate the formation of a stable strengthening phase structure during the PBF-LB process and inhibit the generation of cracks.

[0059] Zr and B act as grain boundary strengthening elements in nickel-based alloys, improving grain boundary strength and the material's high-temperature performance. However, excessive Zr and B content can lead to liquefaction cracking during additive manufacturing, especially during rapid heating and cooling. By controlling the Zr content to 0.02wt% to 0.1wt%, preferably 0.02wt% to 0.07wt%, and reducing the B content to 0.003wt% to 0.015wt%, preferably 0.003wt% to 0.011wt%, cracking sensitivity can be effectively reduced without affecting the material's high-temperature performance. Co can improve oxidation resistance in nickel-based alloys, but excessive Co content can affect the material's thermal stability and generate high residual stresses during PBF-LB, increasing the risk of cracking. Therefore, reducing the Co content to 2.0wt% to 8.0wt%, preferably 2.0wt% to 6.0wt%, can significantly reduce the impact of residual stress while retaining the necessary oxidation resistance, improving its suitability for PBF-LB.

[0060] Al and Ti, as key elements in the γ' strengthening phase, significantly impact the alloy's high-temperature strength and structural stability. By optimizing the combined Al and Ti content to 6.5wt% to 7.4wt%, a stable γ' phase distribution can be achieved during the PBF-LB process, further improving the material's high-temperature strength and creep resistance while effectively reducing cracking tendencies.

[0061] Through the above-mentioned composition optimization, the cracking sensitivity of Alloy738 powder in the PBF-LB process was significantly reduced. The optimized alloy can maintain high-temperature strength and creep resistance while reducing cracking, making it suitable for the preparation of single crystal or near-single crystal structures in additive manufacturing.

[0062] PBF-LB process

[0063] According to an embodiment of the present disclosure, the described PBF-LB process is a method for performing PBF-LB additive manufacturing on any of the optimized nickel-based superalloy powders provided above to form a nickel-based superalloy single crystal component, i.e., a 3D printing method for nickel-based superalloy single crystal components. The method generally involves controlling a laser beam, shaped by a diffractive optical element (DOE) to form a flat-top spot, according to a preset scanning path and process parameters, to selectively melt the nickel-based superalloy powder layered on a substrate to form stacked and consolidated layers until the single crystal component is completed.

[0064] Figure 1 It should be understood that the above-mentioned 3D printing method involved in the present disclosure is to use Figure 1 The conventional 3D printing method mainly involves using a control system 18 to drive the following operations: driving the powder in the powder storage 12 to be supplied to the working plane 19 of the printing chamber 11 or, in other embodiments, using a powder drop container arranged in the printing chamber 11 to release the powder on the substrate 14, thereafter driving the powder spreading device 16 (blade / roller) to move along the working plane to evenly cover the powder on the substrate 14 with a powder layer having a specific layer thickness, thereafter driving the laser beam according to a preset scanning path and process parameters (configured in the 3D model) to selectively melt the powder layer spread on the substrate 14 to form a solidified layer, thereafter driving the forming cylinder 13 to descend a distance of a layer thickness and continue to supply powder, spread powder and melt the powder layer, accumulating layer by layer until the forming preparation of the component 17 matching the designed 3D model structure is completed on the substrate 14 (i.e., in the powder bed 15). In addition, there are some other operations involved, such as the supply and control of protective gas and wind field, monitoring of the printing process, etc., which will not be expanded one by one here.

[0065] It should be understood that the laser beam is processed by various optical elements configured in the optical path to achieve precise melting scanning on the powder layer. The optical elements configured in the optical path include, for example, a laser 21, a collimator 22, a beam expander 23 (which may be eliminated in other embodiments), a deflection mirror 25 (galvanometer), and a focusing mirror 26 (F-Theta lens) along the propagation path of the laser beam. After being emitted from the laser 21, the laser beam is collimated by the collimator 22, expanded in diameter by the beam expander 23, deflected and controlled by the deflection mirror 25, and precisely focused by the focusing mirror 26 before irradiating the powder layer.

[0066] According to an embodiment of the PBF-LB process disclosed herein, a diffractive optical element 24 (DOE) is configured in the optical path. For example, the diffractive optical element 24 can be configured in the optical path between the beam expander 23 and the deflection mirror 25 to shape the laser beam emitted from the beam expander 23 from a Gaussian laser beam with a Gaussian spot distribution to a flat-top laser beam with a flat-top spot distribution (e.g., a circular flat-top laser beam). The shaped laser beam then passes through the deflection mirror 25 and the focusing mirror 26 in sequence to irradiate the powder layer.

[0067] The present disclosure introduces beam shaping technology into the PBF-LB process to manufacture nickel-based high-temperature alloy single crystal components, which can significantly improve the control ability of the molten pool morphology and the flexibility of adjusting the heat flux vector at the solidification front. It should be understood that the traditional Gaussian laser beam will produce a high temperature gradient during the melting process, which easily leads to deep melting and strong convection, which is very unfavorable for single crystal growth. By using a diffractive optical element 24 to shape the laser beam into a flat-top distribution, the laser energy can be more evenly distributed in the molten pool, reducing the temperature gradient of the molten pool and reducing Marangoni convection. In addition, the flat-top laser beam not only improves the dynamic behavior of the molten pool, but the resulting heat conduction molten pool also promotes a stable and controllable melting and solidification process. Because the molten pool profile and solidification direction are more stable and the molten pool width-to-depth ratio is larger, the material can grow better along the construction direction during solidification, which is crucial for the formation of strong textures along the construction direction. At the same time, the optimized flat-top spot size and the precise matching of other PBF-LB process parameters cause the solidification heat flux vector to periodically deflect to at least two of the target single crystal orientation configurations. <100> crystal orientation, thereby inducing a single crystal dynamic crystal selection effect, which is crucial for the formation of single crystal / near single crystal structure.

[0068] This paper systematically optimizes the process of difficult-to-weld nickel-based high-temperature alloys represented by Alloy713 (K418) and Alloy738, aiming to effectively control the melting heat flux vector to achieve dense, crack-free single crystal / near-single crystal PBF-LB additive manufacturing.

[0069] According to the disclosed PBF-LB process implementation, the process optimization design not only introduces a DOE to shape the laser beam spot into a flat-top spot, but also involves optimizing process parameters. The optimized process parameters include a laser power of 50-500W, a laser scanning speed of 50-1500mm / s, a scan line spacing of 0.02-0.18mm, a layer thickness of 40-60μm, and a spot diameter of 50-1000μm. Precise control of these parameters not only affects the efficiency of the melting process but also directly affects the microstructure and performance of the final component.

[0070] For example, in one specific example, the optimized process parameters were set to 380W laser power, 500mm / s laser scanning speed, 0.055mm scanning line spacing, 60μm layer thickness, and 200μm spot diameter. This combination not only achieves a good balance between energy input and material melting, but also ensures sufficient bonding between the layers, which is beneficial to the density and uniformity of the final component. Through this process optimization, single crystal components can be produced with higher precision and lower defect rates.

[0071] According to the embodiment of the PBF-LB process disclosed herein, the optimized process parameters further include: a ratio of the molten pool width to the molten pool depth of 2 to 5, a ratio of the molten pool width to the scan line spacing of 2 to 5, and a ratio of the molten pool depth to the layer thickness of 1.1 to 3.

[0072] It should be understood that controlling the ratio of the molten pool width to the depth between 2 and 5 can maintain the balanced shape of the molten pool, avoid the molten pool being too deep or too shallow, facilitate the control of the heat flow vector during melting, and reduce crack sensitivity. Controlling the ratio of the molten pool width to the scanning line spacing between 2 and 5 can make the overlap of the molten pool sufficient but not excessive, thereby improving the interlayer bonding effect and the density of the component. Controlling the ratio of the molten pool depth to the layer thickness between 1.1 and 3 can enable the molten pool to achieve sufficient melting and good metallurgical bonding during the deposition process of each layer, so as to obtain a dense and uniform component structure. By reasonably controlling these three geometric ratios, the optimized PBF-LB process can achieve morphological stability and energy input uniformity of the molten pool, making the melting process more controlled and providing process support for the realization of single crystal or near-single crystal components.

[0073] Test Example 1

[0074] According to a specific test example of the present disclosure, the nickel-based high-temperature alloy powder described above (optimized Alloy713 (K418)) was used, and the composition was selected as 13wt% Cr, 4.8wt% Mo, 2.05wt% Nb, 6wt% Al, 0.75wt% Ti, 0.145wt% C, 0.0055wt% B, 0.075wt% Zr, 0.25wt% Si, 0.125wt% Mn, 1.25wt% Fe, 0.25wt% Cu and the balance Ni as the powder raw material for the PBF-LB process. The material was prepared, and the DOE shaping scheme described above was introduced in the PBF-LB process to shape the Gaussian laser beam into a circular flat-top laser beam. At the same time, the optimized process parameters were adopted, and the laser power of 380 W, the laser scanning speed of 500 mm / s, the scanning line spacing of 0.055 mm, the layer thickness of 60 μm and the spot diameter of 200 μm were selected for specific melting scanning control. During the scanning process, the ratio of the molten pool width to the molten pool depth was controlled to be 3.4, the ratio of the molten pool width to the scanning line spacing was controlled to be 4.6, and the ratio of the molten pool depth to the layer thickness was controlled to be 1.3. Finally, the nickel-based high-temperature alloy component specimens were prepared.

[0075] Tissue Characterization of Test Case 1

[0076] The prepared nickel-based high-temperature alloy component samples were sampled by wire-cutting and polished according to the standard metallographic sample preparation method. The samples were observed using an optical microscope. Figure 2 As shown in the figure, there are no cracks on the surface of the sample, only a small amount of pores caused by insufficient fusion, and the density can reach more than 98%. Figure 3 As shown in Figure 2, SEM-EBSD testing was performed on an area of ​​600μm × 1200μm within the sample, revealing a near-single-crystalline structure. The grain boundary angle is a key parameter for describing single-crystalline, near-single-crystalline, and polycrystalline materials. It refers to the difference in crystal orientation between two adjacent grains, expressed as an angle. When the maximum grain boundary angle is less than 15°, the material is defined as single crystal; when the maximum grain boundary angle is less than 30°, the material is defined as near-single crystal. Using conventional processes to manufacture the nickel-based superalloy described above, the grain boundary length density per unit area in the range of 15° to 30° was 14.8 (1 / mm), and the grain boundary length density per unit area above 30° was 16.7 (1 / mm). The nickel-based high-temperature alloy described above was manufactured using the process provided in Test Example 1 of the present disclosure. The grain boundary length density per unit area of ​​the sample in the range of 15° to 30° was 26.39 (1 / mm), and the grain boundary length density per unit area above 30° was 1.81 (1 / mm). The grain boundaries above 30° were basically eliminated, indicating that the sample had a near-single crystal structure.

[0077] It should be understood that grain boundary length density refers to the total length of grain boundaries per unit area, and is usually used to express the number or length density of grain boundaries. The unit "1 / mm" represents the concept of grain boundary length density - that is, the total length of grain boundaries per unit area (mm 2 ) The total length of the grain boundary within the grain boundary (mm). This unit of expression comes from the ratio of length to area in the calculation (mm / mm 2 ), thus simplifying to 1 / mm.

[0078] In microstructural characterization, MUD (Maximum Uniform Density) usually reflects texture strength. Specifically, MUD is used to quantify the preference of grains for a specific orientation. The higher the MUD value, the more concentrated the grain orientation is in a specific direction, and the greater the texture strength; the lower the MUD value, the more uniform and random the grain orientation distribution is, and the weaker the texture strength. When the nickel-based high-temperature alloy described above is manufactured using a conventional process, the MUD value of the sample is 10; and when the nickel-based high-temperature alloy described above is manufactured using the process provided in Test Example 1 of the present disclosure, the MUD value of the sample is 16. This shows that the sample prepared using the technology disclosed in this disclosure has a strong texture.

[0079] Test Example 2

[0080] According to a specific test example of the present disclosure, the nickel-based high-temperature alloy powder described above (optimized Alloy738) was used, and the composition was selected as 16wt% Cr, 3.45wt% Al, 3.45wt% Ti, 2wt% Mo, 1wt% Nb, 0.06wt% Zr, 0.009wt% B, 0.09wt% C, 1.9wt% Ta, 2.7wt% W, 5wt% Co, 0.025wt% Fe, 0.01wt% Mn, 0.15wt% Si, 0.0075wt% S and the balance Ni as PBF-L The powder raw materials of process B were used, and the DOE shaping scheme described above was introduced in the PBF-LB process to shape the Gaussian laser beam into a circular flat-top laser beam. At the same time, the optimized process parameters were adopted, and the laser power of 390W, the laser scanning speed of 1050mm / s, the scanning line spacing of 0.177mm, the layer thickness of 40μm and the spot diameter of 200μm were selected for specific melting scanning control. During the scanning process, the ratio of the molten pool width to the molten pool depth was controlled to be 3.6, the ratio of the molten pool width to the scanning line spacing was controlled to be 2.7, and the ratio of the molten pool depth to the layer thickness was controlled to be 2.3, and finally a nickel-based high-temperature alloy component specimen was prepared.

[0081] Tissue Characterization of Test Case 2

[0082] like Figure 4As shown, SEM-EBSD testing was performed on the area of ​​513μm×1138μm inside the sample, and the results showed that the interior of the sample showed a near-single crystal structure. The nickel-based high-temperature alloy described above was manufactured using the process provided in Test Example 2 of the present disclosure. The grain boundary length density per unit area of ​​the sample in the range of 15° to 30° was 35.12 (1 / mm), and the grain boundary length density per unit area above 30° was 2.52 (1 / mm). The grain boundaries above 30° were basically eliminated, indicating that the sample had a near-single crystal structure. The nickel-based high-temperature alloy described above was manufactured using a conventional process, and the MUD value of the sample was 10; while the nickel-based high-temperature alloy described above was manufactured using the process provided in Test Example 2 of the present disclosure, the MUD value of the sample was 17, indicating that the sample prepared using the technology disclosed in the present disclosure has a strong texture.

[0083] It can be seen from Test Example 1 and Test Example 2 that the preparation of single crystal structure was successfully achieved through the aforementioned composition optimization, beam shaping and process parameter regulation. Composition optimization makes the high-temperature phase transformation behavior of the alloy more controllable, reduces the cracking sensitivity of the material, enhances its fluidity, and promotes uniform bonding between molten layers. Secondly, the use of flat-top laser beam shaping technology significantly improves the thermal field distribution of the molten pool, reduces the temperature gradient, reduces thermal stress, and thus helps to form a uniform solidification structure. This uniformity effectively prevents macroscopic stress concentration caused by local overheating or cooling during the crystallization process. Finally, the optimized process parameters make the melting and solidification processes more coordinated, thereby achieving good fusion and mutual influence between each layer.

[0084] The nickel-based high-temperature alloy single crystal component disclosed in the present invention has achieved specific grain boundary structure characteristics through composition design and laser powder bed fusion (PBF-LB) process parameter optimization, that is, the grain boundary length density is high in the low angle range and significantly reduced in the high angle range. Specifically, the grain boundary length density of the nickel-based high-temperature alloy single crystal component disclosed in the present invention is effectively controlled to no more than 35.2 (1 / mm) in the grain boundary angle range of 15° to 30°; and in the grain boundary angle range of more than 30°, the grain boundary length density is further controlled to no more than 2.6 (1 / mm). It can be seen that the number of grain boundaries with large angle differences is extremely small or even almost disappears. This feature reflects the high consistency of grain orientation within the component, that is, the structure characteristics close to that of a single crystal.

[0085] From the perspective of microstructure, the grain boundary distribution pattern disclosed in the present invention shows that the orientation differences between most grains in the material are small, concentrated in the range of 15° to 30°, while high-angle grain boundaries exceeding 30° are greatly reduced or even eliminated. Such a significantly reduced density of high-angle grain boundaries can reduce stress concentration points inside the material, avoid microscopic failure mechanisms such as grain boundary sliding that lead to cracking under high temperature or mechanical load, thereby improving the material's high-temperature strength, creep resistance, and crack resistance. At the same time, this distribution method further enhances the material's resistance to thermal fatigue, especially in high-temperature fluctuating environments. Overall, the single crystal components prepared by the process disclosed in the present invention have been optimized in performance, achieving excellent thermal stability and high-temperature performance.

[0086] DOE fast switching device

[0087] To achieve free switching between different spot shapes (circular Gaussian spot / circular / triangular / rectangular flat-top spot) and reduce repeated installation errors during DOE switching, thereby better meeting the spot shape requirements for nickel-based superalloy single crystal production, the present disclosure also relates to a device for achieving rapid DOE switching. This device is used as part of the additive manufacturing equipment disclosed in the present disclosure.

[0088] Figure 5 FIG2 shows a schematic diagram of the exploded structure of the DOE fast switching device in the optical path according to an embodiment of the present disclosure. Figure 6 FIG2 shows a schematic diagram of the structure of the DOE fast switching device in use in the optical path according to an embodiment of the present disclosure. Figure 7 The figure shows a schematic diagram of the local use state of the DOE fast switching device in the optical path according to the embodiment of the present disclosure. Figure 5-7 The device is arranged in the optical path before the laser beam enters the deflection mirror 25, more specifically, in the optical path between the beam expander 23 and the deflection mirror 25 (it should be understood that in the optical path without the beam expander 23, the device can be arranged in the optical path between the collimator 22 and the deflection mirror 25).

[0089] The device includes a supporting portion 31, a separating portion 32 and a mounting portion 33. The supporting portion 31 is fixed in the optical path, the separating portion 32 is detachably fixed to the supporting portion 31, and the mounting portion 33 is fixed to the separating portion 32 and is used to mount the diffractive optical element.

[0090] Specifically, the support portion 31 is fixed to the beam expander 23 and the deflecting mirror 25 respectively by two long positioning pins 34a and 34b for positioning and two long screws 35a and 35b for fixing. The beam expander 23 is sleeved in the connecting plate 30. The long positioning pins 34a and 34b and the long screws 35a and 35b pass through the connecting plate 30 to fix the support portion 31 and the deflecting mirror 25. The separating portion 32 is fixed to the support portion 31 by two short positioning pins 36a and 36b for positioning and two short screws 37a and 37b for fixing.

[0091] When switching the DOE, the support portion 31 remains fixed between the beam expander 23 and the deflecting mirror 25 in the optical path and is not disassembled. The DOE is separated from the optical path by removing the separator 32 from the support portion 31. Specifically, when switching the DOE, the support portion 31 remains fixed in the optical path and is not disassembled, and the mounting portion 33 remains fixed on the separator 32 and is not disassembled. By removing the short positioning pins 36a, 36b and the short screws 37a, 37b between the support portion 31 and the separator 32, the separator 32 can be separated from the support portion 31, that is, the DOE is separated from the optical path, thereby achieving the switching of the DOE without disassembling other original optical path components, reducing the repeated installation error when switching the DOE. This switching mechanism not only improves the convenience of operation, but also provides strong technical support for the efficient manufacturing of high-performance nickel-based high-temperature alloy single crystal parts.

[0092] In some examples, the separator 32 is interlocked with the support portion 31 so that, when installed, the DOE is embedded within at least a portion of the groove of the support portion 31. This effectively utilizes space and meets the need for DOE switching within a compact design space. Any slight displacement or deviation in the optical path can affect the quality and characteristics of the final beam. This interlocking arrangement provides greater mechanical stability in a fixed state, ensuring that the beam's propagation path and quality are not affected by external vibrations or improper operation during laser beam transmission.

[0093] In some examples, the mounting portion 33 also includes a displacement adjuster 33a and / or a displacement adjuster 33b to achieve high-precision fine-tuning of the DOE position in the X-axis and / or Y-axis directions. The displacement adjuster 33a is, for example, configured to adjust the displacement of the DOE in the Y-axis direction, and the displacement adjuster 33b is, for example, configured to adjust the displacement of the DOE in the X-axis direction. This bidirectional adjustment function enables precise control of the propagation path of the laser beam after switching the DOE, ensuring the stability of the spot shape and improving the accuracy of the optical system. In addition, the mounting portion 33 also includes a built-in threaded retaining ring 33c for fixing the DOE. The arrangement of this threaded retaining ring prevents the DOE from being displaced by vibration or other external factors during operation, ensuring the stability of the optical system. Furthermore, through the integrated fixing method, operators can quickly switch DOEs without having to worry about loosening or displacement of components, thereby optimizing the overall workflow.

[0094] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the contents disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered as exemplary only, and the present disclosure is not limited to the precise structures described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof.

Claims

1. A method for additively manufacturing a nickel-based high-temperature alloy single crystal component from powder, wherein the powder comprises the following elements by weight: Chromium (Cr): 12wt%~14wt%, Molybdenum (Mo): 4.5wt%~5.7wt%, Niobium (Nb): 1.5wt% to 2.3wt%, Aluminum (Al): 5.5wt% to 6.5wt%, Titanium (Ti): 0.5wt% to 1wt%, Carbon (C): 0.1wt%~0.28wt%, Zirconium (Zr): 0.02wt% to 0.1wt%, Boron (B): ≤0.01wt%, Silicon (Si): ≤0.5wt%, Manganese (Mn): ≤0.25wt%, Iron (Fe): ≤2.5wt%, Copper (Cu): ≤0.5wt%, Nickel (Ni): balance; The method comprises: According to a preset scanning path and process parameters, controlling a laser beam in the form of a flat-top spot, which is shaped by a diffractive optical element at least during the additive manufacturing process, to selectively melt the powder layered on the substrate to form stacked and consolidated layers until the single crystal component is manufactured; The process parameters are as follows: laser power 50-500 W, laser scanning speed 50-1500 mm / s, scanning line spacing 0.02-0.18 mm, layer thickness 40-60 μm, spot diameter 50-1000 μm, ratio of molten pool width to molten pool depth 2-5, ratio of molten pool width to scanning line spacing 2-5, and ratio of molten pool depth to layer thickness 1.1-3.

2. The method according to claim 1, wherein the constituent elements of the powder include one or more selected from the following: Carbon (C) is selected as 0.1wt% to 0.19wt%, Molybdenum (Mo) is selected as 4.5wt% to 5.1wt%, Boron (B) is selected from 0.001wt% to 0.01wt%, Zirconium (Zr) is selected as 0.05wt% to 0.1wt%, Niobium (Nb) is selected to be 1.8wt% to 2.3wt%.

3. A method for additively manufacturing a nickel-based high-temperature alloy single crystal component from powder, wherein the powder comprises the following elements by weight: Chromium (Cr): 15.7wt%~16.3wt%, Aluminum (Al): 3.2wt% to 3.7wt%, Titanium (Ti): 3.2wt% to 3.7wt%, Molybdenum (Mo): 1.5wt%~2.5wt%, Niobium (Nb): 0.6wt% to 1.4wt%, Zirconium (Zr): 0.02wt% to 0.1wt%, Boron (B): 0.003wt%~0.015wt%, Carbon (C): 0.05wt%~0.13wt%, Tantalum (Ta): 1.5wt% to 2.3wt%, Tungsten (W): 2.4wt%~3.0wt%, Cobalt (Co): 2.0wt%~8.0wt%, Iron (Fe): ≤0.05wt%, Manganese (Mn): ≤0.02wt%, Silicon (Si): ≤0.3wt%, Sulfur (S): ≤0.015wt%, Nickel (Ni): balance; The method comprises: According to a preset scanning path and process parameters, controlling a laser beam in the form of a flat-top spot, which is shaped by a diffractive optical element at least during the additive manufacturing process, to selectively melt the powder layered on the substrate to form stacked and consolidated layers until the single crystal component is manufactured; The process parameters are as follows: laser power 50-500 W, laser scanning speed 50-1500 mm / s, scanning line spacing 0.02-0.18 mm, layer thickness 40-60 μm, spot diameter 50-1000 μm, ratio of molten pool width to molten pool depth 2-5, ratio of molten pool width to scanning line spacing 2-5, and ratio of molten pool depth to layer thickness 1.1-3.

4. The method according to claim 3, wherein the constituent elements of the powder include one or more selected from the following: Molybdenum (Mo) is selected as 1.6wt% to 2.1wt%, Niobium (Nb) is selected as 0.7wt% to 1.2wt%, Carbon (C) is selected as 0.08wt% to 0.12wt%, Tantalum (Ta) is selected as 1.6wt% to 2.1wt%, Tungsten (W) is selected as 2.5wt% to 2.9wt%, Zirconium (Zr) is selected as 0.02wt% to 0.07wt%, Boron (B) is selected as 0.003wt% to 0.011wt%, Cobalt (Co) is selected to be 2.0wt% to 6.0wt%.

5. The method according to claim 3, wherein the combination of aluminum and titanium (Al+Ti) is selected to be 6.5 wt% to 7.4 wt%.

6. A nickel-based high-temperature alloy single crystal component obtained according to the method according to any one of claims 1 to 5.

7. The single crystal component according to claim 6, wherein the single crystal component has the following grain boundary structure characteristics: In the range of 15° to 30° grain boundary angle, the grain boundary length density does not exceed 35.2 mm / mm 2 ; In the grain boundary angle range above 30°, the grain boundary length density does not exceed 2.6 mm / mm 2 .

8. A device for implementing the switching of the diffractive optical element in the method according to any one of claims 1 to 5, the device being constructed in the optical path before the laser beam enters the deflection mirror and configured to include: a supporting portion, the supporting portion being fixed in the optical path; a separation portion, the separation portion being detachably fixed to the support portion; as well as a mounting portion, the mounting portion being fixed to the separating portion and being used to mount the diffractive optical element; When the diffractive optical element is switched, the diffractive optical element is separated from the optical path by detaching the separation portion from the support portion. 9 . The device according to claim 8 , wherein the supporting portion is fixed between the beam expander and the deflecting mirror in the optical path and is not disassembled when the diffractive optical element is switched. 10 . The device according to claim 8 , wherein the mounting portion comprises at least one displacement adjuster for adjusting the displacement of the diffractive optical element in the X-axis and / or Y-axis directions. 11 . The device according to claim 8 , wherein the separation portion is engaged with the support portion so that the diffractive optical element is embedded in at least a portion of the groove of the support portion in an installed state.

12. An additive manufacturing device comprising the apparatus according to any one of claims 8 to 11.

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