A pure tungsten material active cooling leading edge component and a manufacturing method thereof

Abstract

The application relates to a pure tungsten material active cooling leading edge component and a manufacturing method thereof, and belongs to the technical field of aircraft thermal protection. The manufacturing method is as follows: vacuum low-temperature drying treatment is carried out on pure tungsten material powder; the D10 of the pure tungsten material powder is 45-50 mu m, the D50 is 72-78 mu m, and the D90 is 100-108 mu m; the loose bulk density is greater than or equal to 10.5 g / cm 3 ; the pure tungsten material powder is subjected to electron beam selective additive manufacturing to obtain a blank; the blank is placed in a heat treatment furnace for heat treatment; the heating temperature of the heat treatment is 1100-1300 DEG C, and the holding time is 1-2 h; the surface of the blank is processed twice on a sweating structure layer by using a femtosecond laser to obtain a three-layer three-runner leading edge component. The uniform spreading of the cooling medium outside the leading edge component realizes self-driven thermal protection; moreover, the leading edge component has good high-temperature mechanical properties and fatigue resistance, so that the aircraft can be used back and forth.

Description

Technical Field

[0001] This invention relates to the field of aircraft thermal protection technology, and in particular to an active cooling leading edge component made of pure tungsten and its manufacturing method. Background Technology

[0002] Hypersonic vehicles generate enormous aerodynamic heat due to air friction during supersonic flight, potentially exceeding 10 MW / m². 2 The extreme heat flux density poses a significant challenge to the safe flight of hypersonic vehicles. To enable the vehicle to be used repeatedly for extended periods, non-ablative thermal protection methods must be employed to ensure the safety and reliability of the vehicle's leading edge.

[0003] Self-extraction sweating cooling is a highly efficient and promising active cooling thermal protection method for the leading edge. Its mechanism involves the cooling medium undergoing transport, heat exchange, and phase change processes through a multi-stage flow channel structure driven by capillary force, forming a protective gas film layer on the component surface to isolate the ultra-high temperature heat flow generated by friction between the air and the component. The sweating cooling thermal protection scheme has two main advantages: 1) stronger cooling capacity, primarily because liquids with high specific heat capacity (such as water) are generally chosen as the cooling medium, allowing it to absorb more heat during phase change; 2) the sweating cooling thermal protection uses a multi-stage transport channel similar to a leaf, enabling autonomous transport of the cooling medium under capillary force without the need for an additional power unit, further reducing weight. However, in practical applications, the sweating active cooling thermal protection scheme has not achieved ideal results. Related research has found that the main reason for the reduced thermal protection effect is the immaturity of the multi-stage flow channel structure design and fabrication technology, and the low controllability of the flow channel distribution and dimensions, leading to difficulties in transporting the cooling medium.

[0004] Currently, the processing methods for sweating-type active cooling multi-stage flow channel structures are powder sintering and layer etching. Powder sintering prepares porous media by sintering spherical metal powders or composite materials, but the flow channel distribution and size cannot be controlled. Layer etching etches flow channels on a thin plate and then diffuses and welds them layer by layer. The flow channels are controllable, but the design and processing of complex flow channels results in poor performance and high cost.

[0005] Therefore, there is an urgent need for a sweating-type active cooling thermal protection component with high thermal protection effect and a composite manufacturing method. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a pure tungsten material active cooling leading edge component and its manufacturing method, so as to solve the problem of poor thermal protection effect of existing leading edge components.

[0007] On one hand, the present invention provides a method for manufacturing a pure tungsten material actively cooled leading edge component, comprising the following steps:

[0008] S1: Powder pretreatment, involving vacuum low-temperature drying of pure tungsten powder; the pure tungsten powder has a D10 of 45–50 μm, a D50 of 72–78 μm, and a D90 of 100–108 μm; and a bulk density ≥10.5 g / cm³. 3 ;

[0009] S2: Additive manufacturing, pure tungsten powder is selectively added by electron beam according to the leading edge component model to obtain a blank; the blank consists of an internal dense layer, a middle porous material layer and a surface sweating structure layer.

[0010] S4: Heat treatment, the blank is placed in a heat treatment furnace for heat treatment; the heating temperature of the heat treatment is 1100-1300℃, and the holding time is 1-2h;

[0011] S5: Machining, removing sintered powder and impurities from the surface of the heat-treated blank, and then processing it;

[0012] S6: A three-layer, three-channel leading edge component is produced by performing two processing operations on the surface sweating structure layer of the blank using a femtosecond laser.

[0013] Furthermore, in step S1, the flowability of the dried pure tungsten powder is ≤6.5s / 50g.

[0014] Furthermore, the purity of the pure tungsten powder is ≥99.95%.

[0015] Furthermore, in step S2, before additive manufacturing, the pure tungsten powder is preheated at a temperature of 900-1100℃.

[0016] Furthermore, the preheating treatment adopts an electron beam defocusing heating method, with the following process parameters: beam current 10-20mA, scanning speed 3-6m / s, and powder thickness 40-60μm.

[0017] Furthermore, in step S2, the additive manufacturing employs selective electron beam melting. When preparing the internal dense layer and the surface sweating structure layer, the process parameters are: beam current 15-20mA; scanning speed 0.5-1.0m / s; overlap spacing 80-100μm; powder thickness 40-60μm.

[0018] When preparing the intermediate porous material layer, the process parameters for electron beam selective sintering are: beam current 10-20mA; scanning speed 3-6m / s; and powder thickness 40-60μm.

[0019] Furthermore, the thickness of the surface sweating structure layer is 500-800 μm, the thickness of the inner dense layer is 10-15 mm, and the density of the inner dense layer and the surface sweating structure layer is above 99%.

[0020] Furthermore, the thickness of the intermediate porous material layer is 5-10 mm, and the porosity of the intermediate porous material layer is 30-50%.

[0021] Furthermore, in the femtosecond laser processing, the two femtosecond laser processes are femtosecond laser drilling and femtosecond laser surface microstructure processing:

[0022] The process parameters for femtosecond laser drilling are as follows: laser spot diameter 10-20μm; laser pulse width 500-800fs; laser wavelength 1030nm; single pulse energy 40-50μJ; repetition frequency 500-700kHz; scanning rate 200-400mm / s.

[0023] The parameters for femtosecond laser surface microstructure processing are as follows: laser spot diameter 50-70μm; pulse width 100-300fs; laser wavelength 1030nm; single pulse energy 40-50μJ; repetition frequency 1-3kHz; and scanning rate 0.5-1.0mm / s.

[0024] On the other hand, the present invention provides a pure tungsten material active cooling leading edge component, which comprises, from the inside out, an inner dense layer, an intermediate porous material layer, and a surface sweating structure layer. The inner dense layer is provided with conventional fractal channels with a pore size ≥ 1 mm; the intermediate porous material layer is provided with three-dimensional void channels with a diameter of 60 μm-200 μm; and the surface sweating structure layer is provided with microscale sweating channels with a pore size of 30-50 μm.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] 1. This invention provides a method for manufacturing a sweating active cooling leading edge component, which is used to prepare a leading edge component made of pure tungsten material. By combining additive manufacturing and femtosecond laser processing, a leading edge component with a surface sweating structure layer, a middle porous material layer and an internal dense layer can be prepared. The three layers are metallurgically bonded, and each of the three layers contains a conventional fractal flow channel, a three-dimensional void flow channel and a microscale sweating flow channel, and the flow channels are interconnected. The dimensional accuracy is high. In addition, the preparation method is relatively simple and easy to control.

[0027] 2. In this invention, by designing the model and controlling the process parameters and scanning strategy in the additive manufacturing process, it is possible to form three-dimensional void channels with a diameter of 60-200 μm and conventional fractal channels with a pore size of ≥1 mm in the middle porous material layer and the inner dense layer, respectively. Finally, microscale sweating channels with a pore size of 30-50 μm are processed on the surface sweating structure layer by femtosecond laser, resulting in high forming efficiency.

[0028] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from the description and drawings, which are particularly pointed out. Attached Figure Description

[0029] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0030] Figure 1 This is a schematic diagram of the leading edge component of a certain type of aircraft.

[0031] Figure 2 This is a schematic cross-sectional view of a leading-edge component of a certain type of aircraft.

[0032] Figure 3 Microscale sweating pathway diagram using femtosecond laser;

[0033] In the figure, 1. Surface sweating structure layer; 2. Middle porous material layer; 3. Internal dense layer; 4. Microscale sweating channel; 5. Three-dimensional void channel; 6. Conventional fractal channel; 7. Cooling medium. Detailed Implementation

[0034] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0035] Leading-edge components are critical structural parts in aircraft, facing severe thermal protection challenges during high Mach number flight. Self-suction active cooling allows the leading edge to achieve autonomous cooling without power, enabling it to operate at higher temperatures. Currently, the main fabrication processes for leading-edge components include powder sintering, lamination etching, and additive manufacturing. However, existing processes suffer from poor stability, high control difficulty, and low forming accuracy, making it impossible to fabricate complex flow channels and potentially clogging the sweating channels, thus affecting the cooling effect.

[0036] Therefore, the present invention provides a method for manufacturing a pure tungsten material actively cooled leading edge component, characterized by comprising the following steps:

[0037] S1: Powder pretreatment, involving vacuum low-temperature drying of pure tungsten powder; the pure tungsten powder has a D10 of 45–50 μm, a D50 of 72–78 μm, and a D90 of 100–108 μm; and a bulk density ≥10.5 g / cm³. 3 ;

[0038] S2: Additive manufacturing, pure tungsten powder is selectively added by electron beam according to the leading edge component model to obtain a blank; the blank consists of an internal dense layer, a middle porous material layer and a surface sweating structure layer.

[0039] S4: Heat treatment, the blank is placed in a heat treatment furnace for heat treatment; the heating temperature of the heat treatment is 1100-1300℃, and the holding time is 1-2h;

[0040] S5: Machining, removing sintered powder and impurities from the surface of the heat-treated blank, and then processing it;

[0041] S6: A three-layer, three-channel leading edge component is produced by performing two processing operations on the surface sweating structure layer of the blank using a femtosecond laser.

[0042] Compared with existing technologies, the preparation method provided by this invention, through the combination of additive manufacturing and femtosecond laser processing, can fabricate a leading edge component with a three-layer structure, consisting of a surface sweating structure layer 1, a middle porous material layer 2, and an inner dense layer 3, from the outside to the inside. Furthermore, microscale sweating channels 4, three-dimensional void channels 5, and conventional fractal channels 6 are respectively fabricated on the three-layer structure, and these channels are interconnected. Cooling medium 7 sequentially flows through the conventional fractal channel 6, the three-dimensional void channel 5, and the microscale sweating channel 4. Under capillary action, the cooling medium 7 seeps out from the microscale sweating channel 4, undergoing a phase change and absorbing heat; and a gas film is formed on the leading edge surface, thereby achieving the purpose of cooling. The leading edge component obtained by this invention has high channel dimensional accuracy, does not have the problem of channel blockage, and the preparation method is relatively simple and easy to control.

[0043] It should be noted that in this invention, the raw material powder is the initial material for preparing the leading edge component, and its properties directly affect the quality of the leading edge component. Therefore, the pure tungsten powder needs to be dried to control its flowability to ≤6.5s / 50g (Hall flow rate), which facilitates the subsequent preparation of the leading edge component and ensures the formation and precision of the flow channel.

[0044] Specifically, in step S1, the loose packing density of the dried pure tungsten powder is ≥10.5 g / cm³. 3 .

[0045] It should be noted that in this invention, the loose packing density has a significant impact on the density of the additive material. A lower loose packing density is prone to generating incomplete fusion defects inside the material, which can seriously affect the formation of the flow channel.

[0046] Specifically, in step S1, the pure tungsten powder has a D10 of 45-50 μm, a D50 of 72-78 μm, and a D90 of 100-108 μm.

[0047] It should be noted that, in this invention, uniformly distributed powder can improve the stability of powder spreading, resulting in a defect-free leading edge component and ensuring the forming and precision of the flow channel.

[0048] Specifically, the purity of the pure tungsten powder is ≥99.95%.

[0049] It should be noted that in this invention, high-purity pure tungsten powder is selected, which has less impurity content, making it easier to form in additive manufacturing and preventing particulate impurities from clogging the channels during the preparation process of the surface sweating structure layer, the middle porous material layer and the internal dense layer.

[0050] Specifically, in step S2, before additive manufacturing, the pure tungsten powder is preheated at a temperature of 900-1100℃.

[0051] It should be noted that in this invention, the additive sample model is divided from the inside to the surface into an internal dense layer, an intermediate porous material layer, and a surface sweating structure layer of different thicknesses. During the additive manufacturing process, a layer of pure tungsten powder is uniformly spread on the substrate, and different process parameters are set according to the internal dense layer, the intermediate porous material layer, and the surface sweating structure layer. After the first layer of pure tungsten powder is formed, powder is spread again on the basis of the first layer, and the above process is repeated to obtain a blank with a three-layer structure.

[0052] When spreading the first layer of pure tungsten powder, it is necessary to preheat it. On the one hand, this can provide initial energy to prevent cracks from appearing on the resulting blank, which would affect its strength. On the other hand, it can give the pure tungsten powder better thermal conductivity, electrical conductivity and mechanical stability, which will facilitate the subsequent spreading, sintering or melting of pure tungsten powder.

[0053] Preferably, the preheating temperature is 950-1000℃.

[0054] Specifically, the substrate is made of 316L stainless steel.

[0055] Specifically, the preheating treatment adopts an electron beam defocusing heating method, with the following process parameters: beam current 10-20mA, scanning speed 3-6m / s, and powder thickness 40-60μm.

[0056] When pure tungsten powder is preheated using the above method, the temperature distribution of the pure tungsten powder is uniform, and there will be no stress concentration problem, which facilitates the subsequent preparation of blanks layer by layer.

[0057] It should be noted that in this invention, pure tungsten blanks are prepared using electron beam selective additive manufacturing equipment. In order to ensure the density of the internal dense layer, the surface sweating structure layer and the middle porous material layer, as well as to facilitate subsequent femtosecond laser processing and channel precision, the preparation parameters for each layer are different.

[0058] Specifically, in step S2, the additive manufacturing employs selective electron beam melting. When preparing the internal dense layer and the surface sweating structure layer, the process parameters are: beam current 15-20mA; scanning speed 0.5-1.0m / s; overlap spacing 80-100μm; powder thickness 40-60μm.

[0059] With the above process parameters, a high-density internal dense layer and surface sweating structure layer were obtained, both with a density exceeding 99% and high strength. During service, the surface sweating structure layer of the leading edge component is in direct contact with the air and bears the highest heat; its main function is protection. Therefore, the thickness of the surface sweating structure layer in the manufactured leading edge component is above 500 μm. However, when its thickness gradually increases to above 800 μm, it becomes difficult to prepare subsequent microscale sweating channels. Therefore, the thickness of the surface sweating structure layer is controlled at 500-800 μm, and the thickness of the internal dense layer is 10-15 mm.

[0060] Specifically, in step S2, when preparing the intermediate porous material layer, the process parameters for electron beam selective sintering are: beam current 10-20mA; scanning speed 3-6m / s; and powder thickness 40-60μm.

[0061] With the above process parameters, the porosity of the resulting intermediate porous material layer is 30-50%, and its thickness is 5-10 mm. Located between the surface sweating structure layer and the inner dense layer, this intermediate porous material layer is a transitional layer. The cooling medium in the leading edge component diffuses and permeates from the inner dense layer to the surface sweating structure layer. To avoid hindering the diffusion of the cooling medium, the porosity of the intermediate porous material layer is 30-50%. When the porosity of the intermediate porous material layer is greater than 50%, the overall strength of the leading edge component decreases; when the porosity is less than 30%, it hinders the diffusion and permeation of the cooling medium, resulting in a low diffusion rate and inability to form effective protection on the surface sweating structure layer.

[0062] Specifically, to obtain a blank using additive manufacturing, the blank needs to be heat-treated; the heating temperature of the heat treatment is 1100-1300℃, and the holding time is 1-2h, so as to ensure that microscale sweating channels are subsequently formed on the surface of the blank using a femtosecond laser.

[0063] The leading edge component mainly cools itself through the principle of sweating. A three-layer structure blank is obtained by additive manufacturing. The three layers are, from the inside to the outside, an inner dense layer, an intermediate porous material layer, and a surface sweating structure layer. Conventional fractal flow channels and three-dimensional void flow channels are respectively set in the inner dense layer and the intermediate porous material layer, and the two are interconnected. The pore diameter of the conventional fractal flow channel is ≥1mm; the pore diameter of the three-dimensional void flow channel is 60~200μm.

[0064] To achieve the above-mentioned sweating cooling, a femtosecond laser was used to prepare microscale sweating channels with a pore size of 30-50 μm on the surface sweating structure layer. The resulting channels have high precision and do not have clogging problems, thus ensuring the sweating cooling effect of the leading edge component.

[0065] Specifically, the femtosecond laser processing includes the following steps:

[0066] T1: Fix the blank and set parameters;

[0067] T2: Femtosecond laser drilling: Using a femtosecond laser to perform laser drilling on the sweating structure layer on the surface of the blank, ensuring that the laser beam is perpendicular to the surface of the blank;

[0068] T3: Femtosecond laser surface microstructure processing: Using a femtosecond laser to process the surface of a component to form a hydrophilic microstructure, which facilitates the spread of the cooling medium.

[0069] It should be noted that a series of regularly arranged microchannels with apertures ≤50μm are prepared on the surface of the component using femtosecond lasers; at the same time, the surface is modified using femtosecond lasers to improve the wettability of the material on the surface of the component, obtain sufficiently high capillary pressure, overcome the effect of gravity, and realize the self-suction of the cooling medium.

[0070] Specifically, the process parameters for femtosecond laser drilling are as follows: laser spot diameter 10-20μm; laser pulse width 500-800fs; laser wavelength 1030nm; single pulse energy 40-50μJ; repetition frequency 500-700kHz; scanning rate 200-400mm / s.

[0071] Specifically, the femtosecond laser surface microstructure processing parameters are as follows: laser spot diameter 50-70μm; pulse width 100-300fs; laser wavelength 1030nm; single pulse energy 40-50μJ; repetition frequency 1-3kHz; and scanning rate 0.5-1.0mm / s.

[0072] By using a femtosecond laser to drill holes in the surface sweating structure layer, ensuring that the laser beam is perpendicular to the surface sweating structure layer of the blank, it can directly penetrate the surface sweating structure layer and connect with the middle porous material layer. This allows the cooling medium to diffuse directly from the inner dense layer to the surface sweating structure layer through conventional fractal channels, three-dimensional void channels, and microscale sweating channels in sequence, forming a protective layer around the surface sweating structure layer and achieving self-driven thermal protection.

[0073] The pure tungsten material active cooling leading edge component comprises, from the inside out, an inner dense layer, an intermediate porous material layer, and a surface sweating structure layer. The density of the inner dense layer and the surface sweating structure layer is above 99%. The thickness of the surface sweating structure layer is 500-800 μm, and the thickness of the inner dense layer is 10-15 mm. The porosity of the intermediate porous material layer is 30-50%, and its thickness is 5-10 mm. The inner dense layer contains conventional fractal channels with a pore size ≥1 mm. The intermediate porous material layer contains three-dimensional void channels with a diameter of 60 μm-200 μm. The surface sweating structure layer contains microscale sweating channels with a pore size of 30-50 μm. The conventional fractal channels, the three-dimensional void channels, and the microscale sweating channels are interconnected.

[0074] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.

[0075] Example 1

[0076] This embodiment provides a method for manufacturing a pure tungsten material actively cooled leading edge component, including the following steps:

[0077] S1: Powder pretreatment, vacuum low-temperature drying treatment (100-120℃, 1-2h) of pure tungsten powder to improve the flowability of raw materials;

[0078] In this embodiment, the raw material is pure tungsten powder. The tungsten powder has a D10 of 49 μm, a D50 of 73 μm, a D90 of 103 μm, a flowability (Hall flow rate) of 5.5 s / 50 g, and a purity of ≥99.95%; the loose packing density is 10.5 g / cm³. 3 ;

[0079] S2: Additive manufacturing. Based on the structural characteristics of the leading edge component model, slicing is performed to prepare an additive sample model. The additive sample model is then split from the inside to the surface into an internal dense layer, an intermediate porous material layer, and a surface sweating structure layer of different thicknesses. During the additive manufacturing process, a layer of pure tungsten powder is uniformly spread on a 316L stainless steel substrate. Different process parameters are set according to the internal dense layer, the intermediate porous material layer, and the surface sweating structure layer. After the first layer of pure tungsten powder is formed, another layer of powder is spread on top of the first layer. The above process is repeated to obtain a blank with a three-layer structure.

[0080] The powder was heated to 1100℃ using an electron beam defocusing heating method. The electron beam defocusing process parameters were: beam current 15mA; scanning speed 5m / s; powder thickness 50μm; and high-speed reciprocating scanning strategy.

[0081] Powder was prepared into a blank using selective electron beam additive manufacturing technology. The blank comprises a three-layer structure, consisting of an inner dense layer, a middle porous material layer, and a surface sweating structure layer from the inside out. During the preparation of the inner dense layer and the surface sweating structure layer, the electron beam current for selective melting was 20 mA; the scanning speed was 1.0 m / s; the overlap distance was 90 μm; the powder thickness was 50 μm; the density of the inner dense layer and the surface sweating structure layer was above 99%; and the inner dense layer contained conventional fractal channels with a pore size of 2 mm.

[0082] When preparing the intermediate porous material layer, the electron beam selective sintering process parameters are as follows: beam current 10mA, scanning speed 5m / s, powder thickness 50μm, scanning strategy is high-speed reciprocating scanning, the density of the intermediate porous material layer is 40%, and the intermediate porous material layer contains three-dimensional void channels with pore size of 60-200μm.

[0083] S3: Heat treatment, heat treatment of the blank in a vacuum environment at a temperature of 1200℃ for 2 hours.

[0084] S4: Machining, which involves removing sintered powder and impurities from the surface of the heat-treated blank before machining.

[0085] S5: Using femtosecond lasers to process the surface of the pre-processed blank to create microscale sweat channels, including:

[0086] T1: Fix the processed blank and then set the operating parameters of the femtosecond laser;

[0087] T2: Femtosecond laser drilling: Laser drilling is performed on the surface sweating structure layer of the blank using a femtosecond laser, ensuring that the laser beam is perpendicular to the surface of the blank. The aperture of the microscale sweating channel is 30-50μm and penetrates the surface sweating structure layer.

[0088] The laser spot diameter is 10 μm; the laser pulse width is 500 fs; the laser wavelength is 1030 nm; the single pulse energy is 40 μJ; the repetition frequency is 600 kHz; and the scanning rate is 200 mm / s.

[0089] T3: Femtosecond Laser Surface Microstructure Fabrication: Femtosecond lasers are used to process the surface of components, forming hydrophilic microstructures that facilitate the spread of cooling media. The femtosecond laser surface microstructure fabrication parameters are: laser spot diameter 50 μm; pulse width 300 fs; laser wavelength 1030 nm; single pulse energy 50 μJ; repetition frequency 1 kHz; and scanning rate 0.5 mm / s. A leading-edge component is then fabricated.

[0090] Reference Figure 1 and Figure 2 The leading edge component is conical and consists of a three-layer structure: an inner dense layer, a middle porous material layer, and a surface sweating structure layer, with thicknesses of 10 mm, 5 mm, and 0.5 mm, respectively. The inner dense layer contains conventional fractal channels with pore sizes ≥ 1 mm; the middle porous material layer contains three-dimensional void channels with pore sizes of 60-200 μm; and the surface sweating structure layer contains microscale sweating channels with pore sizes of 30-50 μm (see reference). Figure 3 ).

[0091] Example 2

[0092] The preparation process of Example 2 is largely the same as that of Example 1, except that the electron beam additive manufacturing process is different in Example 2.

[0093] This embodiment provides a method for manufacturing a pure tungsten material actively cooled leading edge component, including the following steps:

[0094] S1: Powder pretreatment, vacuum low-temperature drying treatment (100-120℃, 1-2h) of pure tungsten powder to improve the flowability of raw materials;

[0095] The pure tungsten powder has a D10 of 47 μm, a D50 of 76 μm, a D90 of 104 μm, a flowability (Hall flow rate) of 6.0 s / 50 g, and a purity of ≥99.95%; its loose packing density is 10.5 g / cm³. 3 ;

[0096] S2: Additive manufacturing. Based on the structural characteristics of the leading edge component model, slicing is performed to prepare an additive sample model. The additive sample model is then split from the inside to the surface into an internal dense layer, an intermediate porous material layer, and a surface sweating structure layer of different thicknesses. During the additive manufacturing process, a layer of pure tungsten powder is uniformly spread on a 316L stainless steel substrate. Different process parameters are set according to the internal dense layer, the intermediate porous material layer, and the surface sweating structure layer. After the first layer of pure tungsten powder is formed, another layer of powder is spread on top of the first layer. The above process is repeated to obtain a blank with a three-layer structure.

[0097] The powder was heated to 1000℃ using an electron beam defocusing heating method. The electron beam defocusing process parameters were: beam current 10mA; scanning speed 4m / s; powder thickness 50μm; and high-speed reciprocating scanning strategy.

[0098] Powder is prepared into a blank using an electron beam selective additive manufacturing system. The blank comprises a three-layer structure, consisting of an inner dense layer, a middle porous material layer, and a surface sweating structure layer from the inside out. During the preparation of the inner dense layer and the surface sweating structure layer, the electron beam current for selective melting is 15 mA; the scanning speed is 0.5 m / s; the overlap distance is 80 μm; the powder thickness is 50 μm; the density of the inner dense layer and the surface sweating structure layer is above 99%; and the inner dense layer contains conventional fractal channels with a pore size of 2 mm.

[0099] When preparing the intermediate porous material layer, the electron beam selective sintering process parameters are: beam current 20mA, scanning speed 6m / s, powder thickness 50μm, scanning strategy is high-speed reciprocating scanning, the density of the intermediate porous material layer is 40%, and the intermediate porous material layer contains three-dimensional void channels with pore size of 60-200μm.

[0100] S3: Heat treatment, heat treatment of the blank in a vacuum environment at a temperature of 1200℃ for 2 hours.

[0101] S4: Machining, which involves removing sintered powder and impurities from the surface of the heat-treated blank before machining.

[0102] S5: Using femtosecond lasers to process the surface of the pre-processed blank to create microscale sweat channels, including:

[0103] T1: Fix the processed blank and then set the operating parameters of the femtosecond laser;

[0104] T2: Femtosecond laser drilling: Laser drilling is performed on the surface sweating structure layer of the blank using a femtosecond laser, ensuring that the laser beam is perpendicular to the surface of the blank. The aperture of the microscale sweating channel is 30-50μm and penetrates the surface sweating structure layer.

[0105] The laser spot diameter is 10 μm; the laser pulse width is 500 fs; the laser wavelength is 1030 nm; the single pulse energy is 40 μJ; the repetition frequency is 600 kHz; and the scanning rate is 200 mm / s.

[0106] T3: Femtosecond Laser Surface Microstructure Fabrication: Femtosecond lasers are used to process the surface of components, forming hydrophilic microstructures that facilitate the spread of cooling media. The femtosecond laser surface microstructure fabrication parameters are: laser spot diameter 50 μm; pulse width 300 fs; laser wavelength 1030 nm; single pulse energy 50 μJ; repetition frequency 1 kHz; and scanning rate 0.5 mm / s. A leading-edge component is then fabricated.

[0107] Reference Figure 1 and Figure 2 The leading edge component is conical and consists of three layers: an inner dense layer, an intermediate porous material layer, and a surface sweating structure layer, from the inside out. The inner dense layer contains conventional fractal channels with a pore size ≥1mm; the intermediate porous material layer contains three-dimensional void channels with a pore size of 60-200μm; and the surface sweating structure layer contains microscale sweating channels with a pore size of 30-50μm.

[0108] Example 3

[0109] The preparation process of Example 3 is largely the same as that of Example 1, except that the femtosecond laser processing technology is different in Example 3.

[0110] This embodiment provides a method for manufacturing a pure tungsten material actively cooled leading edge component, including the following steps:

[0111] S1: Powder pretreatment, vacuum low-temperature drying treatment (100-120℃, 1-2h) of pure tungsten powder to improve the flowability of raw materials;

[0112] The pure tungsten powder has a D10 of 45 μm, a D50 of 73 μm, a D90 of 101 μm, a flowability (Hall flow rate) of 6.5 s / 50 g, and a purity of ≥99.95%; its loose packing density is 10.5 g / cm³. 3 ;

[0113] S2: Additive manufacturing. Based on the structural characteristics of the leading edge component model, slicing is performed to prepare an additive sample model. The additive sample model is then split from the inside to the surface into an internal dense layer, an intermediate porous material layer, and a surface sweating structure layer of different thicknesses. During the additive manufacturing process, a layer of pure tungsten powder is uniformly spread on a 316L stainless steel substrate. Different process parameters are set according to the internal dense layer, the intermediate porous material layer, and the surface sweating structure layer. After the first layer of pure tungsten powder is formed, another layer of powder is spread on top of the first layer. The above process is repeated to obtain a blank with a three-layer structure.

[0114] The powder was heated to 1100℃ using an electron beam defocusing heating method. The electron beam defocusing process parameters were: beam current 15mA; scanning speed 5m / s; powder thickness 50μm; and high-speed reciprocating scanning strategy.

[0115] Powder is prepared into a blank using an electron beam selective additive manufacturing system. The blank comprises a three-layer structure, consisting of an inner dense layer, a middle porous material layer, and a surface sweating structure layer from the inside out. During the preparation of the inner dense layer and the surface sweating structure layer, the electron beam current for selective melting is 20 mA; the scanning speed is 1.0 m / s; the overlap distance is 90 μm; the powder thickness is 50 μm; the density of the inner dense layer and the surface sweating structure layer is above 99%; and the inner dense layer contains conventional fractal channels with a pore size of 2 mm.

[0116] When preparing the intermediate porous material layer, the electron beam selective sintering process parameters are as follows: beam current 10mA, scanning speed 5m / s, powder thickness 50μm, scanning strategy is high-speed reciprocating scanning, the density of the intermediate porous material layer is 40%, and the intermediate porous material layer contains three-dimensional void channels with pore size of 60-200μm.

[0117] S3: Heat treatment, heat treatment of the blank in a vacuum environment at a temperature of 1200℃ for 2 hours.

[0118] S4: Machining, which involves removing sintered powder and impurities from the surface of the heat-treated blank before machining.

[0119] S5: Using femtosecond lasers to process the surface of the pre-processed blank to create microscale sweat channels, including:

[0120] T1: Fix the processed blank and then set the operating parameters of the femtosecond laser;

[0121] T2: Femtosecond laser drilling: Laser drilling is performed on the surface sweating structure layer of the blank using a femtosecond laser, ensuring that the laser beam is perpendicular to the surface of the blank. The aperture of the microscale sweating channel is 30-50μm and penetrates the surface sweating structure layer.

[0122] The laser spot diameter is 10 μm; the laser pulse width is 500 fs; the laser wavelength is 1030 nm; the single pulse energy is 50 μJ; the repetition frequency is 500 kHz; and the scanning rate is 200 mm / s.

[0123] T3: Femtosecond laser surface microstructure processing: Femtosecond lasers are used to process the surface of components to form hydrophilic microstructures, which facilitate the spread of cooling media. The parameters for femtosecond laser surface microstructure processing are: laser spot diameter 60μm; pulse width 200fs; laser wavelength 1030nm; single pulse energy 50μJ; repetition frequency 3kHz; and scanning rate 1.0mm / s, to obtain the leading edge component.

[0124] Reference Figure 1 and Figure 2 The leading edge component is conical and consists of three layers: an inner dense layer, an intermediate porous material layer, and a surface sweating structure layer, from the inside out. The inner dense layer contains conventional fractal channels with a pore size ≥1mm; the intermediate porous material layer contains three-dimensional void channels with a pore size of 60-200μm; and the surface sweating structure layer contains microscale sweating channels with a pore size of 30-50μm.

[0125] Comparative Example 1

[0126] This comparative example provides a sintering manufacturing method for a sweating active cooling leading edge component, including the following steps:

[0127] S1: Sieving Process: Based on the service conditions, spherical high-temperature alloy powder materials with the required particle diameter are selected using a vibrating screen. Urea (CO(NH2)2) pore-forming agent is selected, and urea is ground into powders of different particle diameters, which are then sieved to separate urea with the required particle diameter.

[0128] S2: Powder mixing treatment: The high-temperature alloy powder obtained in S1 is combined with urea in different proportions and mechanically dry-mixed in a ball mill for 4 hours to make the material evenly distributed.

[0129] S3: Compression Molding: Before molding, to improve the strength of the compact and prevent segregation of the powder mixture, an appropriate amount of liquid polyvinyl alcohol is added to the powder as a molding agent and ground evenly. The ground powder is then introduced into the leading edge mold and pressed into a conical porous media leading edge blank under static pressure in a large hydraulic press.

[0130] S4: Sintering and Shaping: First, slowly heat from room temperature to 180℃ to fully decompose the pore-forming agent in the porous blank; then heat to 600℃ and hold for 30-60 minutes to completely reduce the surface oxides of the powder particles, forming sintering necks at the particle interfaces; next, heat to the sintering temperature of 1250℃ and hold for 100-150 minutes to allow sintering to proceed fully and near completion. Finally, reduce the temperature to 500℃ and allow it to cool naturally to room temperature.

[0131] Comparative Example 2

[0132] This comparative example provides a method for etching a layer to manufacture a sweating active cooling leading edge component, including the following steps:

[0133] S1: Plate preparation: First, use organic solvents to clean the surface of the high-temperature alloy sheet to remove surface oil, impurities, etc.

[0134] S2: Plate fixing: Fix the high-temperature alloy sheet on the processing platform to ensure that the high-temperature alloy sheet will not move during the micro-groove processing;

[0135] S3: Parameter Settings: Set all operating parameters for the photolithography or chemical etching equipment;

[0136] S4: Flow channel processing: Using photolithography or chemical etching equipment to process at fixed positions on the surface of a high-temperature alloy thin plate to obtain complex internal flow channels.

[0137] S5: Cleaning: Clean the grooves on the surface of the high-temperature alloy sheet to ensure the wettability of the groove walls and the flow performance of the cooling medium. After cleaning, perform drying.

[0138] S6: Welding: Welding metal plates processed by photolithography or chemical etching to form a layer plate leading edge structure, thereby obtaining a layer plate etching leading edge component.

[0139] Comparative Example 3

[0140] This comparative example provides a laser additive manufacturing method for a sweating-type actively cooled leading edge component, including the following steps:

[0141] S1: Powder pretreatment: Vacuum low-temperature drying treatment of raw materials (100-120℃, 1-2h) to improve the flowability of raw materials;

[0142] In this embodiment, the raw material is GH4099 high-temperature alloy powder, with the following mass percentages: 18.81 wt.% Cr, 6.10 wt.% W, 4.19 wt.% Mo, 6.56 wt.% Co, <0.02 wt.% Mn, 2.07 wt.% Al, 1.28 wt.% Ti, 0.039 wt.% C, and the balance being Ni.

[0143] The GH4099 high-temperature alloy powder has a D10 of 15–20 μm, a D50 of 30–35 μm, a D90 of 45–50 μm, a flowability (Hall flow rate) of 17 s / 50 g, and a loose packing density of 4.6 g / cm³. 3 ;

[0144] S2: Model Design: Based on the structural characteristics of the leading edge component, slice the model to prepare the additive prototype model;

[0145] S3: Additive Manufacturing: Based on the sliced ​​model, the leading edge component is formed by selective laser melting. The laser power of selective laser melting additive manufacturing is 300W, the scanning speed is 960mm / s, the overlap distance is 50μm, the powder thickness is 40μm, and the layer-by-layer rotation is 67°.

[0146] S4: Heat treatment: The blank is heat treated in a vacuum environment at a temperature of 1200℃ for 2 hours.

[0147] S5: Machining: Remove sintered powder and impurities from the surface of the heat-treated blank, and then process it; finally obtain the laser additive manufacturing sweating active cooling leading edge component.

[0148] Performance testing

[0149] The leading edge components obtained in Examples 1-3 and Comparative Examples 1-3 were tested. The leading edge components were directly injected with an oxyacetylene flame at a temperature of 1700K and a heat flux density of 0.32. The temperatures of the inner and outer surfaces of the leading edge components before and after the coolant was introduced were measured. The test results are shown in Table 1 (each group was tested three times and the average value was taken).

[0150] Table 1 Test Results

[0151] Example 1 Self-extraction ≥90％ Example 2 Self-extraction ≥90％ Example 3 Self-extraction ≥90％ Comparative Example 1 water pump ≤85％ Comparative Example 2 water pump ≤80％ Comparative Example 3 water pump ≤65％

[0152] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of manufacturing a pure tungsten material active cooled leading edge member, characterized by, Includes the following steps: S1: Powder pretreatment: Pure tungsten powder is vacuum dried at 100-120℃; the pure tungsten powder has a D10 of 45~50µm, a D50 of 72~78µm, and a D90 of 100~108µm; and a loose packing density ≥10.5g / cm³. 3 ; S2: Additive manufacturing, using electron beam selective additive manufacturing on pure tungsten powder according to the leading edge component model to obtain a blank; the blank consists of an internal dense layer, an intermediate porous material layer, and a surface sweating structure layer; the thickness of the surface sweating structure layer is 500-800µm, the thickness of the internal dense layer is 10-15mm, and the density of the internal dense layer and the surface sweating structure layer is above 99%; the thickness of the intermediate porous material layer is 5-10mm, and the porosity of the intermediate porous material layer is 30-50%; S3: Heat treatment, the blank is placed in a heat treatment furnace for heat treatment; the heating temperature of the heat treatment is 1100-1300℃, and the holding time is 1-2h; S4: Machining, which involves removing sintered powder and impurities from the surface of the heat-treated blank before machining. S5: The femtosecond laser is used to perform two processing operations on the surface sweating structure layer of the blank. The two femtosecond laser processing operations are femtosecond laser drilling and femtosecond laser surface microstructure processing, to obtain a three-layer three-channel leading edge component. The leading edge component consists of an inner dense layer, an intermediate porous material layer and a surface sweating structure layer from the inside to the outside. The inner dense layer is provided with conventional fractal channels with a pore size ≥1mm. The intermediate porous material layer is provided with three-dimensional void channels with a diameter of 60µm-200µm. The surface sweating structure layer is provided with microscale sweating channels with a pore size of 30~50µm. The conventional fractal channels, the three-dimensional void channels and the microscale sweating channels are interconnected.

2. The manufacturing method of the pure tungsten material actively cooled leading edge component according to claim 1, characterized in that, In step S1, the flowability of the dried pure tungsten powder is ≤6.5s / 50g.

3. The manufacturing method of the pure tungsten material actively cooled leading edge component according to claim 1, characterized in that, The purity of the pure tungsten powder is ≥99.95%.

4. The method of claim 1, wherein the pure tungsten material active-cooled leading edge member is manufactured by the steps of: In step S2, before additive manufacturing, the pure tungsten powder is preheated at a temperature of 900-1100℃. ​ 5. The method of claim 4, wherein the pure tungsten material active-cooled leading edge member is manufactured by the steps of: The preheating treatment adopts electron beam defocusing heating method, with the following process parameters: beam current 10-20mA, scanning speed 3-6m / s, and powder thickness 40-60µm. ​ 6. The manufacturing method of the pure tungsten material actively cooled leading edge component according to claim 1, characterized in that, In step S2, when preparing the internal dense layer and the surface sweating structure layer, the additive manufacturing adopts electron beam selective melting, with the following process parameters: beam current 15-20mA. The scanning speed is 0.5-1.0 m / s; the overlap distance is 80-100 µm; and the powder thickness is 40-60 µm. In preparing the intermediate porous material layer, the additive manufacturing process employs selective electron beam sintering with the following process parameters: beam current 10-20 mA; scanning speed 3-6 m / s; and powder thickness 40-60 µm.

7. The manufacturing method of the pure tungsten material actively cooled leading edge component according to claim 1, characterized in that, During femtosecond laser processing, the femtosecond laser drilling process parameters are as follows: laser spot diameter 10-20μm; laser pulse width 500-800fs; laser wavelength 1030nm; single pulse energy 40-50µJ; repetition frequency 500-700kHz; scanning rate 200-400mm / s. The parameters for femtosecond laser surface microstructure processing are as follows: laser spot diameter 50-70μm; pulse width 100-300fs; laser wavelength 1030nm; single pulse energy 40-50µJ; repetition frequency 1-3kHz; and scanning rate 0.5-1.0mm / s.

8. A pure tungsten material active cooled leading edge component, characterized by Obtained by the manufacturing method according to any one of claims 1-7.

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