A high-strength and tough aviation thin plate imitating an armadillo with a shell and a preparation method thereof

Abstract

The present invention discloses a high-strength and tough aviation thin plate imitating an armadillo with a shell and a preparation method thereof, relating to the fields of aviation materials and laser additive manufacturing technology. The high-strength and tough aviation thin plate of the present invention includes a plurality of connection layers arranged in parallel, and a sparse grid layer and a dense grid layer located between adjacent connection layers. The sparse grid layer and the dense grid layer include closely arranged hollow block units, and the connection layer, the sparse grid layer and the dense grid layer form a closed cavity. The preparation method of the present invention uses laser melting deposition additive manufacturing technology to form the connection layer, the sparse grid layer and the dense grid layer, and selective laser melting additive manufacturing technology to form the sparse hollow blocks and the dense hollow blocks. The high-strength and tough thin plate of the present invention can be used for load-bearing structural parts and heat dissipation structural parts in fields such as aerospace.

Description

Technical Field

[0001] The present invention relates to the fields of aviation materials and metal laser additive manufacturing technology, and particularly relates to a high-strength and tough aviation thin plate imitating the shell of an armadillo and a preparation method thereof. Background Art

[0002] With the development of additive manufacturing technology, more and more metal components printed by additive manufacturing technology are applied in fields such as aerospace. At present, for the printed metal components, while ensuring excellent mechanical properties, it is particularly important to reduce the weight and improve the high-temperature resistance of the metal components. Nickel-based superalloys (such as Inconel 718) are the most widely used among the three types of high-temperature alloys of iron, cobalt, and nickel-based. They are a type of high-temperature alloy with high strength, good oxidation resistance, good heat resistance, and excellent resistance to gas corrosion, and are widely used in aviation, aerospace, chemical industry, petrochemical industry, and other special applications in the marine application field.

[0003] The body of an armadillo is covered with a shell, which is composed of bony plates of tough keratinized skin. Its shell is composed of overlapping epidermal scales, and these scale structures have excellent mechanical properties and high hardness. When the armadillo curls up in a defensive posture, its shell can bounce back bullets. Taking the nine-banded armadillo as an example: the shell of the armadillo includes a front shell, a banded shell, and a rear shell. The structures of these three parts of the shell are similar, but the structure of the banded shell is more complex. The front and rear parts of each banded shell overlap and connect, and the rear part is on the outside and the front part is on the inside. The internal pores in the front part of the banded shell are much larger than those in the rear part and present a hollow brick structure. This banded shell structure not only ensures excellent mechanical properties but also effectively reduces the weight, and at the same time, this structure can also effectively dissipate heat.

[0004] Currently, there are two methods in metal additive manufacturing: powder bed fusion and powder feeding. Among them, the selective laser melting technology (powder bed fusion) for metal additive manufacturing is mature and can process precision metal structures and complex metal structures;

[0005] The laser metal deposition technology (powder feeding) can efficiently and rapidly form metal forming parts. Summary of the Invention

[0006] In view of the above analysis, the purpose of the present invention is to provide a high-strength and tough aviation thin plate imitating the shell of an armadillo and a preparation method thereof. For any load-bearing and heat-dissipating structural parts in current aerospace, combining the excellent mechanical properties of the armadillo shell, a thin plate structure with a fast heat dissipation, high hardness, and a combination of dense and sparse layers is provided, and a laser additive manufacturing method combining powder bed fusion and powder feeding is adopted, using the nickel-based superalloy Inconel 718 material with excellent mechanical properties.

[0007] The purpose of the present invention is mainly achieved through the following technical solutions:

[0008] A high-strength and high-toughness aviation thin plate imitating an armadillo with a shell, including a first connection layer, a second connection layer, and a third connection layer arranged in parallel in sequence.

[0009] The first connection layer and the second connection layer are connected by a sparse mesh layer.

[0010] Sparse hollow blocks are arranged in the mesh holes of the sparse mesh layer.

[0011] The second connection layer and the third connection layer are connected by a dense mesh layer.

[0012] Dense hollow blocks are arranged in the mesh holes of the dense mesh layer.

[0013] Further, the thicknesses of the first connection layer, the second connection layer, and the third connection layer are 0.5 mm.

[0014] Further, the cross-sectional shapes of the sparse mesh layer and the dense mesh layer are both equi-wall square meshes arranged closely.

[0015] Further, the heights of the sparse mesh layer and the dense mesh layer are both 1.5 mm.

[0016] Further, the wall thickness in the sparse mesh layer and the dense mesh layer is 1 mm.

[0017] Further, the shapes of the cross-sections of the sparse hollow blocks and the dense hollow blocks in the vertical direction are both equi-wall quadrilaterals.

[0018] Further, the equi-wall quadrilateral is an equi-wall square.

[0019] Further, the outer dimensions of the sparse hollow block are length: width: height = 6:6:1.5 mm, and the inner dimensions are length: width: height = 5:5:1 mm;

[0020] The wall thickness of the cross-section of the sparse hollow block perpendicular to the vertical direction is 0.5 mm, and the wall thickness in the vertical direction is 0.25 mm.

[0021] Further, the outer dimensions of the dense hollow block are length: width: height = 2.5:2.5:1.5 mm, and the inner dimensions are length: width: height = 2:2:1 mm;

[0022] The wall thickness of the dense hollow block is 0.25 mm.

[0023] Further, the preparation method of the above high-strength and high-toughness aviation thin plate includes the following steps:

[0024] S1, select Inconel 718 nickel-based superalloy powder or Inconel 625 nickel-based superalloy powder or other aviation materials such as TiAl alloy with a purity above 99.9% and a particle size of 15 μm - 30 μm, 50 μm - 150 μm;

[0025] S2. Establish the structure of the high-strength and high-toughness aviation thin plate as described above through 3D modeling software, perform slicing processing, generate a path, and then import it into the printing device;

[0026] S3. Combine two additive manufacturing methods, namely laser melting deposition additive manufacturing and selective laser melting additive manufacturing, to sequentially form the first connection layer, sparse hollow blocks, sparse grid layer, second connection layer, dense hollow blocks, dense grid layer, and third connection layer of the high-strength and high-toughness aviation thin plate.

[0027] The laser melting deposition additive manufacturing method includes the following steps:

[0028] Step A: Import the thin-layer structure model, generate the printing trajectory program for the first connection layer, and conduct a trial run;

[0029] Step B: Select Inconel 718 powder with a purity above 99.9% and a particle size of 50μm - 150μm, place a sufficient amount of powder in a vacuum drying oven at 150°C for 1.5h for drying treatment, and then put the treated powder into a three-tube coaxial powder feeder;

[0030] Step C: Provide an Inconel 718 nickel-based superalloy substrate, polish it flat with a grinding machine to remove the surface oxide layer, then clean the surface oil stain of the substrate with alcohol, and then put the substrate into the printing box and adjust the position of the substrate;

[0031] Step D: Select argon with a purity of 99.99% as the protective gas, fill argon in the printing box until the oxygen concentration in the box drops from 5000PPM to about 500PPM, and maintain this concentration;

[0032] Step E: Select argon with a purity of 99.999% as the powder feeding gas;

[0033] Step F: According to the thin-layer model data, use laser melting deposition to print the corresponding first connection layer model part of the thin-layer model on the surface of the substrate, that is, print the connection layer structure on the substrate surface, with a laser power of 200W - 400W (for example, 230W), a scanning speed of 150mm / s - 250mm / s (for example, 120mm / s), a scanning spacing of 100μm - 120μm (for example, 100μm), a spot diameter of 200μm, and the total powder feeding amount of the four powder feeding tubes of 3.6g / min - 4.2g / min (for example, 3.7g / min);

[0034] Step G: Repeat steps E - F until the preparation of the thin plate is completed to obtain the substrate - first connection layer structure, and the flatness of the surface of the connection layer meets the requirements of selective laser melting additive manufacturing.

[0035] Further, selective laser melting technology is adopted for additive manufacturing of hollow blocks (or the hollow blocks in the same layer form a hollow block layer as a whole).

[0036] Further, the selective laser melting additive manufacturing method includes the following steps:

[0037] Step a: Import a thin plate model and generate model data of hollow blocks (or the hollow blocks in the same layer form a hollow block layer as a whole).

[0038] Step b: Select Inconel 718 powder with a purity above 99.9% and a particle size of 15μm - 30μm, place a sufficient amount of powder in a vacuum drying oven at 150°C for heat preservation for 1.5h for drying treatment, and place the treated powder in a powder cylinder.

[0039] Step c: In the first connection layer formed by the above laser melting deposition additive manufacturing, use the substrate - first connection layer obtained in step G as a new substrate, place it in the forming cylinder and adjust the position of the substrate, that is, the upper surface of the substrate - first connection layer is the surface of the new substrate.

[0040] Step d: Select argon with a purity of 99.999% as the protective gas until the oxygen concentration in the cavity drops to 0PPM.

[0041] Step e: Lay a powder layer on the new substrate, and the thickness of the powder layer is 0.02mm - 0.05mm (for example, 0.04mm).

[0042] Step f: According to the thin plate model data, use selective laser melting to process the hollow blocks in the sparse grid layer corresponding to the thin plate model in the powder layer, with a laser power of 200W - 300W (for example, 210W), a scanning speed of 450mm / s - 570mm / s (for example, 460mm / s), and a scanning spacing of 60μm - 90μm (for example, 80μm).

[0043] Step g: Repeat steps e - f until the preparation of the thin plate is completed, and obtain a new substrate - hollow block (or the hollow blocks in the same layer form a hollow block layer as a whole).

[0044] Further, laser melting deposition technology is adopted for additive manufacturing of the sparse grid layer and the second connection layer, and the second connection layer serves as a structure connecting the sparse grid layer and the dense grid layer.

[0045] Further, the laser melting deposition additive manufacturing method includes the following steps:

[0046] Step A: Import a thin plate model, generate a printing trajectory program for the sparse grid layer and the second connection layer, and run it for a trial.

[0047] Step B: Select Inconel 718 powder with a purity above 99.9% and a particle size of 50 μm to 150 μm. Place a sufficient amount of the powder in a vacuum drying oven at 150 °C and keep it warm for 1.5 h for drying treatment. Then put the treated powder into a three-tube coaxial powder feeder.

[0048] Step C: In the above-mentioned laser selective melting additive manufacturing of the dense grid layer hollow block, use the new substrate-sparse grid layer inner hollow block obtained in step g as the new substrate. Then put the substrate into the printing box and adjust the position of the substrate.

[0049] Step D: Select argon with a purity of 99.99% as the protective gas. Fill the printing box with argon until the oxygen concentration in the box drops from 5000 PPM to about 500 PPM and maintain this concentration.

[0050] Step E: Select argon with a purity of 99.999% as the powder feeding gas.

[0051] Step F: According to the thin plate data, adopt the sparse grid layer and the second connection layer models corresponding to the laser melting deposition thin plate model, that is, additively manufacture and form the sparse grid layer and the second connection layer in sequence between the hollow blocks of the sparse hollow block (or the whole of the sparse hollow blocks in the same layer forms a sparse hollow block layer). The laser power is 200 W to 400 W (for example, 230 W), the scanning speed is 150 mm / s to 250 mm / s (for example, 120 mm / s), the scanning spacing is 100 μm to 120 μm (for example, 100 μm), the spot diameter is 200 μm, and the total powder feeding amount of the four powder feeding tubes is 3.6 g / min to 4.2 g / min (for example, 3.7 g / min).

[0052] Step G: Repeat steps E to F until the preparation of the thin plate is completed, and obtain the new substrate-sparse hollow block (or the whole of the sparse hollow blocks in the same layer forms a sparse hollow block layer), that is, the first connection layer-sparse hollow block (or the whole of the sparse hollow blocks in the same layer forms a sparse hollow block layer)-sparse grid layer-second connection layer.

[0053] Furthermore, adopt the laser selective melting technology to additively manufacture the dense hollow block layer (or the whole of the dense hollow blocks in the same layer forms a sparse hollow block layer).

[0054] Furthermore, the laser selective melting additive manufacturing method includes the following steps:

[0055] Step a: Import the thin plate structure model and generate the model data of the dense hollow block layer (or the whole of the dense hollow blocks in the same layer forms a sparse hollow block layer).

[0056] Step b: Select Inconel 718 powder with a purity above 99.9% and a particle size of 15μm - 30μm. Place a sufficient amount of the powder in a vacuum drying oven at 150°C and keep it warm for 1.5h for drying treatment. Then place the treated powder in the powder cylinder.

[0057] Step c: In the above laser melting deposition additive manufacturing to form a sparse grid layer and a second connection layer, use the first connection layer - sparse hollow block obtained in step G (or the sparse hollow blocks in the same layer as a whole form a sparse hollow block layer) - sparse grid layer - second connection layer as the new substrate. Place it in the forming cylinder and adjust the position of the new substrate, that is, the upper surface of the second connection layer in the new substrate is the surface of the new substrate.

[0058] Step d: Select argon with a purity of 99.999% as the protective gas until the oxygen concentration in the cavity drops to 0PPM.

[0059] Step e: Lay a powder layer on the new substrate, and the thickness of the powder layer is 0.02mm - 0.05mm (for example, 0.04mm).

[0060] Step f: According to the thin plate model data, use selective laser melting to form the dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer) corresponding to the thin plate model in the powder layer. The laser power is 200W - 300W (for example, 210W), the scanning spacing is 60μm - 90μm (for example, 80μm), and the scanning speed is 450mm / s - 570mm / s (for example, 460mm / s).

[0061] Step g: Repeat steps e - f until the preparation of the thin plate is completed, and obtain the new substrate - dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer), that is, the first connection layer - sparse hollow block (or the sparse hollow blocks in the same layer as a whole form a sparse hollow block layer) - sparse grid layer - second connection layer - dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer).

[0062] Furthermore, use laser melting deposition technology for additive manufacturing of a dense grid layer and a third connection layer. The third connection layer serves as a structure connecting the dense grid layer and the outside.

[0063] Furthermore, the laser melting deposition additive manufacturing method includes the following steps:

[0064] Step A: Import the thin plate model, generate the printing trajectory program for the dense grid layer and the third connection layer, and run it for a trial.

[0065] Step B: Select Inconel 718 powder with a purity above 99.9% and a particle size of 50μm - 150μm. Place a sufficient amount of the powder in a vacuum drying oven at 150°C and keep it warm for 1.5h for drying treatment. Then put the treated powder into a three-tube coaxial powder feeder.

[0066] Step C: Use the above-mentioned laser selective melting to fabricate a dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer). The new substrate - dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer) obtained in step g, that is, the first connection layer - sparse hollow block (or the sparse hollow blocks in the same layer as a whole form a sparse hollow block layer) - sparse grid layer - second connection layer - dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer) as the new substrate. Then put the substrate into the printing box and adjust the position of the substrate.

[0067] Step D: Take argon with a purity of 99.99% as the protective gas. Fill the printing box with argon until the oxygen concentration in the box drops from 5000PPM to about 500PPM and maintain this concentration.

[0068] Step E: Select argon with a purity of 99.999% as the powder feeding gas.

[0069] Step F: According to the thin layer model data, use laser melting deposition to fabricate the corresponding dense grid layer and the third connection layer model of the thin plate model, that is, sequentially additively manufacture and form a dense grid layer and a third connection layer between the hollow blocks of the dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer). The laser power is 200W - 400W (for example, 230W), the scanning speed is 150 - 250mm / s (for example, 120mm / s), the scanning spacing is 100μm - 120μm (for example, 100μm), the spot diameter is 200μm, and the total powder output of the four powder tubes is 3.6 - 4.2g / min (for example, 3.7g / min).

[0070] Step G: Repeat steps E - F until the preparation of the thin plate is completed to obtain a dense grid layer - connection layer.

[0071] Regarding Inconel 718:

[0072] Inconel 718 alloy is a precipitation-hardened nickel-chromium-iron alloy containing niobium and molybdenum, which has high strength at 700°C, good toughness, and corrosion resistance in both high and low temperature environments. The supply state can be solution treatment or precipitation hardening state.

[0073] The chemical composition is:

[0074]

[0075]

[0076] For the vacuum drying oven:

[0077] Model: DZF-6056

[0078] The metal powder is heat-insulated at a preset temperature and in a vacuum state to keep the metal powder raw material in a dry state. Preferably, the Inconel 718 nickel-based superalloy is heat-insulated in a vacuum environment at 150°C for 1.5 h.

[0079] For the selective laser melting additive manufacturing technology:

[0080] Model: BSLS001-L laser

[0081] Before the laser beam starts scanning, the powder spreading device first pushes the metal powder flat onto the substrate of the forming cylinder, and then the laser beam selectively melts the powder on the substrate according to the filling contour line of the current layer to process the current layer. Then the forming cylinder descends a layer thickness distance, the powder cylinder rises a certain thickness distance, and the powder spreading device spreads the metal powder on the processed current layer again. The device loads the data of the next layer contour for processing, and processes layer by layer like this until the whole part is processed. The whole processing process is carried out in a processing chamber filled with inert gas protection to prevent the metal from reacting with other gases at high temperatures.

[0082] For the laser metal deposition additive manufacturing technology:

[0083] Model: Hanbang HD80D

[0084] The metal powder material in the three-barrel coaxial powder feeder is transported and sprayed by the drive of an inert gas flow. The powder is sent out by four powder feeding pipes around the laser, and the powder feeding axes of the four powder feeding pipes coincide with the axis of the laser. The powder sprayed and melted in real time by the laser solidifies on the substrate and realizes the three-dimensional manufacturing of the part with the movement of the substrate or the laser head.

[0085] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0086] a) A high-strength and tough aviation thin plate imitating the armadillo's shell provided by the present invention has a grid structure containing hollow blocks from the inside to the outside and from sparse to dense, which is an armadillo-like shell structure, has high strength, and the hollow structure can greatly reduce the structural weight compared with the solid structure and also has good heat dissipation performance;

[0087] b) The preparation method of the thin plate provided by the present invention combines the advantages of the additive manufacturing methods of selective laser melting and laser metal deposition. The complex and dense sparse and dense hollow block layers are manufactured by selective laser melting technology (or the dense hollow blocks in the same layer form a sparse hollow block layer as a whole). In this way, a soft-hard combination structure will appear at the joints within the grid layer, which can effectively improve the specific strength and specific stiffness of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0089] Figure 1 is an exploded view of the thin plate;

[0090] Figure 2 is a positive triaxial side view of the thin plate.

[0091] Figure 3 is the front view of the thin plate

[0092] Figure 4 is a partial cross-sectional view of the sparse layer of the thin plate

[0093] Figure 5 is a partial cross-sectional view of the dense layer of the thin plate

[0094] REFERENCE SIGNS:

[0095] 1 - First connection layer; 2 - Sparse hollow block (or the sparse hollow blocks in the same layer form a sparse hollow block layer as a whole); 3 - Sparse grid layer; 4 - Third connection layer; 5 - Dense grid layer; 6 - Dense hollow block (or the dense hollow blocks in the same layer form a sparse hollow block layer as a whole); 7 - Second connection layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0096] The following will clearly and completely describe the technical solutions in the embodiments of the present disclosure with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present disclosure.

[0097] The present invention provides a high-strength and tough aviation thin plate with an armadillo shell-like structure. Refer to Figures 1 to 2, including a 3-sparse grid layer and a 5-dense hollow block layer (or the dense hollow blocks in the same layer form a sparse hollow block layer as a whole), the 3-sparse grid layer and the 5-dense grid layer respectively contain 2-sparse hollow blocks (or the sparse hollow blocks in the same layer form a sparse hollow block layer as a whole), a 6-dense hollow block layer (or the dense hollow blocks in the same layer form a sparse hollow block layer as a whole), the middle of the sparse and dense grid layers is a dense 7-second connection layer, the 1-first connection layer and the 4-third connection layer can be respectively joined to the adjacent two skins, and the skin and the thin plate form a closed cavity.

[0098] Compared with the prior art, the armadillo-like shell high-strength and high-toughness aviation thin plate structure provided by the present invention has a grid structure with hollow blocks from inside to outside and from sparse to dense, which is an armadillo-like shell structure, has relatively high strength, and the hollow structure can greatly reduce the structural weight compared with the solid structure and also has good heat dissipation performance. Moreover, the additive manufacturing method combining selective laser melting and laser metal deposition technologies takes their respective advantages. The selective laser melting technology is used to manufacture complex and dense sparse hollow blocks (or the sparse hollow blocks in the same layer form a sparse hollow block layer as a whole), and the laser metal deposition technology can continue to additively manufacture the sparse and dense grid layers and the connection layer on the processed parts. Compared with using a single additive manufacturing method, it can better improve the structural performance.

[0099] Exemplarily, in order to obtain such a network structure with hollow blocks from sparse to dense, the above structure is made by an additive manufacturing method. It should be noted that the additive manufacturing technology is a manufacturing technology that stacks layer by layer in ways such as melting, sintering, and photocuring to manufacture complex and dense solid articles. Different from the processing mode of traditional subtractive technologies, it is a "top-down" manufacturing method by material accumulation.

[0100] From the perspective of the forming process and mechanical properties, the inner dimension of the cross-sectional area of each grid of the 3-sparse grid layer is four times that of the cross-sectional area of the 5-dense grid layer. This internal structure conforms to the approximate pore size ratio between the front and the rear in the armadillo-like shell structure, and the internal 2-sparse hollow blocks (or the sparse hollow blocks in the same layer form a sparse hollow block layer as a whole), 6-dense hollow block layer (or the dense hollow blocks in the same layer form a sparse hollow block layer as a whole) are respectively filled in the 3-sparse grid layer and the 5-dense grid layer.

[0101] It should be noted that the structure from inside to outside is from the 3-sparse grid layer to the 5-dense grid layer. The 1-first connection layer and the 4-third connection layer are joined to the adjacent skins on both sides. The interval of the connection layer can realize the function of the soft-hard-soft three-layer structure, which can improve the strength and stiffness of the structure.

[0102] In the above structure, the wall thickness of the corresponding equilateral square cross-section of the 3-sparse grid layer and the 5-dense grid layer is 0.5 mm, and the height is 1.5 mm.

[0103] Similarly, for the above-mentioned 2-sparse hollow blocks (or the sparse hollow blocks in the same layer as a whole form a sparse hollow block layer), the outer dimensions of the hollow block unit are length:width:height = 6:6:1.5 mm, and the inner dimensions are length:width:height = 5:5:1 mm; for the 6-dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer), the outer dimensions of the hollow block unit are length:width:height = 2.5:2.5:1.5 mm, and the inner dimensions are length:width:height = 2:2:1 mm; the wall thickness of the cross-section perpendicular to the additive manufacturing direction of the hollow block unit is 0.5 mm, and the wall thickness in the additive direction is 0.25 mm.

[0104] Similarly, the thicknesses of the 1-first connection layer, 4-third connection layer, and 7-second connection layer are 0.5 mm; the wall thicknesses of the cross-section perpendicular to the additive manufacturing direction and in the additive direction of the hollow block are both 0.25 mm; the thickness of the skin is 0.5 mm to 2 mm.

[0105] From the comprehensive consideration of lightweight and mechanical properties, among the two additive manufacturing technologies, the structure printed by the laser melting deposition technology has a lower density than that of the selective laser melting. Therefore, in this structure composed of sparse-dense grid layers and hollow block units, a soft-hard-soft three-layer structure will appear in the grid layer, which can improve the specific strength and specific stiffness of the structure. The hollow structure also has the advantages of weight reduction and good heat dissipation, and can maintain excellent mechanical properties at high temperatures.

[0106] The present invention also provides a method for preparing a high-strength and tough aerospace thin plate imitating an armadillo with a shell, which respectively uses the selective laser melting technology and the laser melting deposition technology to prepare high-strength and tough thin plates, a method combining the two additive manufacturing technologies.

[0107] It should be noted that the laser melting deposition additive manufacturing technology prints the 1-first connection layer, 3-sparse grid layer, 4-third connection layer, 5-dense grid layer, and 7-second connection layer; the selective laser melting additive manufacturing technology prints the 2-sparse hollow blocks (or the sparse hollow blocks in the same layer as a whole form a sparse hollow block layer), and 6-dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer). The structure manufactured by the selective laser melting technology has a higher density than that of the laser melting deposition technology. The joint between the hollow blocks and the grid layer in the printed grid layer structure will form a soft-hard-soft three-layer structure, greatly improving the strength and stiffness of the structure.

[0108] In addition, nickel-based superalloys (such as Inconel 718) are the most widely used among the three types of iron-based, cobalt-based, and nickel-based superalloys, and are a type of superalloy with high strength, good oxidation resistance, good heat resistance, and excellent resistance to gas corrosion.

[0109] Example 1

[0110] This example provides a high-strength and tough aviation thin plate with an armadillo-like shell and a preparation method. The thin plate is prepared by laser melting deposition technology and selective laser melting technology. The material used is nickel-based superalloy powder, and the equipment used is Hanbang HD80D and BSLS001-L lasers respectively. The specific steps are as follows:

[0111] The laser melting deposition additive manufacturing method includes the following steps:

[0112] Step A: Import the thin layer structure model, generate the printing trajectory program of the first connection layer, and run it for a trial.

[0113] Step B: Select Inconel 718 powder with a purity above 99.9% and a particle size of 50μm - 150μm. Place a sufficient amount of powder in a vacuum drying oven at 150°C for 1.5h for drying treatment, and then put the treated powder into a three-tube coaxial powder feeder.

[0114] Step C: Provide an Inconel 718 nickel-based superalloy substrate, polish it flat with a grinding machine and remove the surface oxide layer, then clean the surface oil stain of the substrate with alcohol, and then put the substrate into the printing box and adjust the position of the substrate.

[0115] Step D: Select argon with a purity of 99.99% as the protective gas, fill argon in the printing box until the oxygen concentration in the box drops from 5000PPM to about 500PPM, and maintain this concentration.

[0116] Step E: Select argon with a purity of 99.999% as the powder feeding gas.

[0117] Step F: According to the thin layer model data, use laser melting deposition to print the corresponding first connection layer model part of the thin layer model, that is, print the connection layer structure on the substrate surface. The laser power is 200W - 400W (for example, 230W), the scanning speed is 150mm / s - 250mm / s (for example, 120mm / s), the scanning spacing is 100μm - 120μm (for example, 100μm), the spot diameter is 200μm, and the total powder feeding amount of the four powder feeding tubes is 3.6g / min - 4.2g / min (for example, 3.7g / min).

[0118] Step G: Repeat steps E - F until the preparation of the thin plate is completed, obtaining the substrate - first connection layer structure, and the flatness of the connection layer surface meets the requirements of selective laser melting additive manufacturing.

[0119] Furthermore, selective laser melting technology is used for additive manufacturing of hollow blocks (or the hollow blocks in the same layer form a hollow block layer as a whole).

[0120] Furthermore, the selective laser melting additive manufacturing method includes the following steps:

[0121] Step a: Import the thin plate model and generate the model data of the sparse hollow blocks (or the sparse hollow block layer formed by the sparse hollow blocks on the same layer).

[0122] Step b: Select Inconel 718 powder with a purity above 99.9% and a particle size of 15μm - 30μm. Place a sufficient amount of the powder in a vacuum drying oven at 150°C for heat preservation for 1.5h for drying treatment, and then place the treated powder in the powder cylinder.

[0123] Step c: In the first connection layer formed by the above laser melting deposition additive manufacturing, use the substrate - first connection layer obtained in step G as the new substrate, place it in the forming cylinder and adjust the position of the substrate, that is, the upper surface of the substrate - first connection layer is the surface of the new substrate.

[0124] Step d: Select argon with a purity of 99.999% as the protective gas until the oxygen concentration in the printing box drops to 0PPM.

[0125] Step e: Lay a powder layer on the new substrate, and the thickness of the powder layer is 0.02mm - 0.05mm (for example, 0.04mm).

[0126] Step f: According to the thin plate model data, use selective laser melting to melt the hollow blocks in the sparse grid layer corresponding to the thin plate model in the powder layer. The laser power is 200W - 300W (for example, 210W), the scanning speed is 450mm / s - 570mm / s (for example, 460mm / s), and the scanning spacing is 60μm - 90μm (for example, 80μm).

[0127] Step g: Repeat steps e - f until the preparation of the thin plate is completed, and obtain the new substrate - sparse hollow blocks (or the sparse hollow block layer formed by the sparse hollow blocks on the same layer).

[0128] Furthermore, use the laser melting deposition technology for additive manufacturing of the sparse grid layer and the second connection layer. The second connection layer is used as the structure connecting the sparse grid layer and the dense grid layer.

[0129] Furthermore, the laser melting deposition additive manufacturing method includes the following steps:

[0130] Step A: Import the thin plate model, generate the printing trajectory program for the sparse grid layer and the second connection layer, and run it for a trial.

[0131] Step B: Select Inconel 718 powder with a purity above 99.9% and a particle size of 50μm - 150μm. Place a sufficient amount of the powder in a vacuum drying oven at 150°C for heat preservation for 1.5h for drying treatment, and then put the treated powder into a three - tube coaxial powder feeder.

[0132] Step C: In the above-mentioned laser selective melting additive manufacturing of the dense grid layer hollow block, use the new substrate-sparse grid layer inner hollow block obtained in step g as the new substrate, then put the substrate into the printing box and adjust the position of the substrate;

[0133] Step D: Take argon with a purity of 99.99% as the protective gas, fill argon in the printing box until the oxygen concentration in the box drops from 5000 PPM to about 500 PPM, and maintain this concentration;

[0134] Step E: Select argon with a purity of 99.999% as the powder feeding gas;

[0135] Step F: According to the thin plate data, use the laser melting deposition to form the corresponding sparse grid layer and the second connection layer model of the thin plate model, that is, additively manufacture and form the sparse grid layer and the second connection layer in sequence between the hollow blocks of the sparse hollow block (or the whole of the sparse hollow blocks in the same layer forms a sparse hollow block layer). The laser power is 200W - 400W (for example, 230W), the scanning speed is 150mm / s - 250mm / s (for example, 120mm / s), the scanning spacing is 100μm - 120μm (for example, 100μm), the spot diameter is 200μm, and the total powder feeding amount of the four powder feeding pipes is 3.6g / min - 4.2g / min (for example, 3.7g / min);

[0136] Step G: Repeat steps E - F until the preparation of the thin plate is completed, and obtain the new substrate-sparse hollow block (or the whole of the sparse hollow blocks in the same layer forms a sparse hollow block layer), that is, the first connection layer-sparse hollow block (or the whole of the sparse hollow blocks in the same layer forms a sparse hollow block layer)-sparse grid layer-second connection layer.

[0137] Furthermore, use the laser selective melting technology to additively manufacture the dense hollow block layer (or the whole of the dense hollow blocks in the same layer forms a sparse hollow block layer).

[0138] Furthermore, the laser selective melting additive manufacturing method includes the following steps:

[0139] Step a: Import the thin plate structure model and generate the model data of the dense hollow block layer (or the whole of the dense hollow blocks in the same layer forms a sparse hollow block layer);

[0140] Step b: Select Inconel 718 powder with a purity of more than 99.9% and a particle size of 15μm - 30μm, place a sufficient amount of powder in a vacuum drying oven at 150°C for heat preservation for 1.5h for drying treatment, and put the treated powder in the powder cylinder;

[0141] Step c: In the above-mentioned laser melting deposition additive manufacturing to form a sparse grid layer and a second connection layer, use the first connection layer-sparse hollow blocks obtained in step G (or the sparse hollow blocks in the same layer form a sparse hollow block layer)-sparse grid layer-second connection layer as the new substrate, place it in the forming cylinder and adjust the position of the new substrate, that is, the upper surface of the second connection layer in the new substrate is the surface of the new substrate;

[0142] Step d: Select argon with a purity of 99.999% as the protective gas until the oxygen concentration in the cavity drops to 0 PPM;

[0143] Step e: Lay a powder layer on the new substrate, and the thickness of the powder layer is 0.02 mm to 0.05 mm (for example, 0.04 mm);

[0144] Step f: According to the thin plate model data, use selective laser melting to form the dense hollow block layer corresponding to the thin plate model in the powder layer (or the dense hollow blocks in the same layer form a sparse hollow block layer), with a laser power of 200 W to 300 W (for example, 210 W), a scanning pitch of 60 μm to 90 μm (for example, 80 μm), and a scanning speed of 450 mm / s to 570 mm / s (for example, 460 mm / s);

[0145] Step g: Repeat steps e to f until the preparation of the thin plate is completed, and obtain the new substrate-dense hollow block layer (or the dense hollow blocks in the same layer form a sparse hollow block layer), that is, the first connection layer-sparse hollow blocks (or the sparse hollow blocks in the same layer form a sparse hollow block layer)-sparse grid layer-second connection layer-dense hollow block layer (or the dense hollow blocks in the same layer form a sparse hollow block layer).

[0146] Furthermore, use laser melting deposition technology for additive manufacturing of a dense grid layer and a third connection layer, and this third connection layer serves as a structure connecting the dense grid layer and the outside world.

[0147] Furthermore, the laser melting deposition additive manufacturing method includes the following steps:

[0148] Step A: Import the thin plate model, generate the printing trajectory program for the dense grid layer and the third connection layer, and run it for a trial;

[0149] Step B: Select Inconel 718 powder with a purity of more than 99.9% and a particle size of 50 μm to 150 μm, place a sufficient amount of powder in a vacuum drying oven at 150 °C for heat preservation for 1.5 h for drying treatment, and then put the treated powder into a three-barrel coaxial powder feeder;

[0150] Step C: Laser selective melting additive manufacturing of dense hollow block layers (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer). The new substrate-dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer) obtained in step g, that is, the first connection layer-sparse hollow block (or the sparse hollow blocks in the same layer as a whole form a sparse hollow block layer)-sparse grid layer-the second connection layer-dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer) is used as the new substrate. Then, put the substrate into the printing box and adjust the position of the substrate well.

[0151] Step D: Take argon with a purity of 99.99% as the protective gas, fill the printing box with argon until the oxygen concentration in the box drops from 5000 PPM to about 500 PPM, and maintain this concentration.

[0152] Step E: Select argon with a purity of 99.999% as the powder feeding gas.

[0153] Step F: According to the thin layer model data, use laser melting deposition to form the dense grid layer and the third connection layer model corresponding to the thin plate model, that is, additively manufacture and form the dense grid layer and the third connection layer in sequence between the hollow blocks of the dense hollow block layer (or the dense hollow blocks in the same layer as a whole form a sparse hollow block layer). The laser power is 200W - 400W (for example, 230W), the scanning speed is 150 - 250mm / s (for example, 120mm / s), the scanning spacing is 100μm - 120μm (for example, 100μm), the spot diameter is 200μm, and the total powder feeding amount of the four powder feeding pipes is 3.6 - 4.2g / min (for example, 3.7g / min).

[0154] Step G: Repeat steps E - F until the preparation of the thin plate is completed to obtain the dense grid layer-connection layer.

[0155] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0156] The above shows and describes the basic principles, main features, and advantages of the present disclosure. Those skilled in the art of this industry should understand that the present disclosure is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present disclosure. Without departing from the spirit and scope of the present disclosure, the present disclosure will have various changes and improvements, and these changes and improvements all fall within the scope of the present disclosure claimed.

Claims

1. A high-strength and tough aviation thin plate imitating an armadillo with a shell, characterized in that, It includes a first connection layer, a second connection layer, and a third connection layer arranged in parallel in sequence. The first connection layer and the second connection layer are connected by a sparse mesh layer. Sparse hollow blocks are arranged in the mesh holes of the sparse mesh layer. The second connection layer and the third connection layer are connected by a dense mesh layer. Dense hollow blocks are arranged in the mesh holes of the dense mesh layer. The middle of the sparse and dense mesh layer is the dense second connection layer. The first connection layer and the third connection layer can be respectively joined to adjacent two skins. The skin and the thin plate form a closed cavity, and an additive manufacturing method combining selective laser melting and laser metal deposition technologies is adopted.

2. The high-strength and high-toughness aviation thin plate according to claim 1, wherein The thicknesses of the first connection layer, the second connection layer, and the third connection layer are 0.5 mm.

3. The high-strength and high-toughness aviation thin plate according to claim 1, wherein The cross-sectional shapes of the sparse mesh layer and the dense mesh layer are both equi-wall square meshes arranged closely.

4. The high-strength and high-toughness aviation thin plate according to claim 1, wherein The heights of the sparse mesh layer and the dense mesh layer are both 1.5 mm.

5. The high-strength and high-toughness aviation thin plate according to claim 1, wherein The wall thicknesses in the sparse mesh layer and the dense mesh layer are 1 mm.

6. The high-strength and high-toughness aviation thin plate according to claim 1, wherein The shapes of the cross-sections of the sparse hollow blocks and the dense hollow blocks in the vertical direction are both equi-wall quadrilaterals.

7. The high-strength and high-toughness aviation thin plate according to claim 6, characterized in that, The equi-wall quadrilateral is an equi-wall square.

8. The high-strength and high-toughness aviation thin plate according to claim 1, wherein, The outer dimensions of the sparse hollow block are length: width: height = 6:6:1.5 mm, and the inner dimensions are length: width: height = 5:5:1 mm. The wall thickness of the cross-section of the sparse hollow block perpendicular to the vertical direction is 0.5 mm, and the wall thickness in the vertical direction is 0.25 mm.

9. The high-strength and high-toughness aviation thin plate according to claim 1, wherein The outer dimensions of the dense hollow block are length: width: height = 2.5:2.5:1.5 mm, and the inner dimensions are length: width: height = 2:2:1 mm. The wall thicknesses of the dense hollow blocks are all 0.25 mm.

10. The high-strength and high-toughness aviation thin plate according to any one of claims 1-9, characterized in that, The preparation method of the high-strength and high-toughness aviation thin plate includes the following steps: S1, Select Inconel 718 nickel-based superalloy powder with a purity of more than 99.9% and particle sizes of 15 μm - 30 μm and 50 μm - 150 μm. S2, Establish the structure of the high-strength and high-toughness aviation thin plate as described in any one of claims 1 - 9 through 3D modeling software, perform slicing processing, generate paths, and then import them into the printing device. S3, Adopt selective laser melting additive manufacturing or selective laser sintering additive manufacturing to prepare the high-strength and high-toughness aviation thin plate, which is formed in sequence as the first connection layer, sparse hollow blocks, sparse mesh layer, second connection layer, dense hollow blocks, dense mesh layer, and third connection layer.

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