4d printed bidirectional intelligent temperature control lattice structure and preparation method therefor

Abstract

A 4D printed bidirectional intelligent temperature control lattice structure and a preparation method therefor. The 4D printed bidirectional intelligent temperature control lattice structure comprises a plurality of microporous lattice unit cells, and the microporous lattice unit cells are arrayed and mirrored to obtain the 4D printed bidirectional intelligent temperature control lattice structure; and each microporous lattice unit cell is a lattice unit cell obtained by stretching a truncated octahedron in the horizontal direction or a lattice unit cell obtained by compressing a truncated octahedron in the horizontal direction, a micropore is one of a rhombic micropore stretched in the horizontal direction, a rhombic micropore compressed in the horizontal direction, a square micropore stretched in the horizontal direction or a square micropore compressed in the horizontal direction, and the truncated octahedron is obtained by truncating a hollow regular octahedron.

Description

A 4D printing bidirectional intelligent temperature control lattice structure and its preparation method

[0001] This application claims priority to Chinese Patent Application No. 202410216762.9 filed on February 28, 2024, and the contents of the above-mentioned Chinese patent application disclosure are hereby incorporated by reference in their entirety as a part of this application. Technical Field

[0002] The present invention belongs to the technical field of additive manufacturing of lattice metals, and specifically relates to a 4D printing bidirectional intelligent temperature control lattice structure and a preparation method thereof. Background Art

[0003] In recent years, with the rapid development of aerospace technology, aircraft have become increasingly high-speed, high-end, and precise. Lattice structures have attracted widespread attention in the aerospace field due to their lightweight, high specific density, and high specific stiffness. Lattice metals not only offer lightweight properties, but also function-driven lattice metal designs can impart more functional properties to the structure.

[0004] However, high-speed flight introduces severe aerodynamic heating. When speeds exceed Mach 6, the leading edge temperature of the aircraft exceeds 1000K. Such high temperatures pose a serious threat to the safe flight of the aircraft and also limit the further iteration and upgrade of high-speed spacecraft. Currently, the multifunctionalization of lattice structures focuses on vibration and noise reduction, as well as buffering and energy absorption. Research on temperature regulation is relatively limited.

[0005] Nickel-titanium alloys have high application potential in the aerospace field due to their excellent shape memory effect and superelastic properties. Utilizing the shape memory effect of nickel-titanium alloys can give lattice structures the functional characteristics of intelligent temperature control. That is, using shape memory alloys to sense changes in ambient temperature, it is possible to enable the lattice structure to intelligently open and close to achieve temperature control. Currently, the shape memory effect of nickel-titanium alloys is used to automatically open the closed-cell lattice structure when the ambient temperature rises and automatically close when the temperature drops, thereby controlling the outflow rate of the coolant and achieving the effect of intelligent temperature control. This design concept of achieving temperature control through the intelligent opening and closing of the lattice structure is rarely reported in the aerospace field. At the same time, the phase transition temperature of existing nickel-titanium shape memory alloy materials is generally low, making it difficult to meet the application requirements of the temperature control function during the flight of aerospace aircraft. The lattice structure that can achieve two-way intelligent temperature control is even less well known to the public.

[0006] Nickel-titanium alloys have superelastic properties and high toughness, which makes it very easy to wear the tool during processing. Traditional processing technology makes it difficult to prepare complex configurations such as lattice metals, which also severely limits the application of nickel-titanium shape memory alloys in the aerospace field. The emergence of additive manufacturing technology has made it possible to prepare nickel-titanium shape memory alloys with complex configurations. Additive manufacturing is also known as 3D printing. The production of three-dimensional objects based on 3D printing that can self-transform physical properties under predetermined stimuli (such as heating, pressurization, electricity, magnetic field, light, etc.) is called 4D printing. 4D-printed products can spontaneously change according to the specific needs of the application scenario and the specific action conditions of the stimulus factors, and exhibit corresponding characteristics.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to provide a 4D printing bidirectional intelligent temperature control lattice structure and a preparation method thereof.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] A 4D-printed bidirectional intelligent temperature-control lattice structure includes a plurality of microporous lattice cells, which are arrayed and mirrored along the x, y, and z directions to obtain a 4D-printed bidirectional intelligent temperature-control lattice structure; the microporous lattice cells are lattice cells obtained by stretching a truncated octahedron in the horizontal direction or by compressing it in the horizontal direction; the micropores are one of diamond micropores stretched in the horizontal direction, diamond micropores compressed in the horizontal direction, square micropores stretched in the horizontal direction, or square micropores compressed in the horizontal direction; and the truncated octahedron is obtained by truncating a regular octahedron with a hollow interior.

[0011] Furthermore, the length: width: height ratio of the lattice unit cell obtained by stretching in the horizontal direction is 2-4:1:1, the length of the lattice unit cell obtained by stretching in the horizontal direction is 5 mm to 30 mm, the length ratio of the two diagonal lines of the diamond micropores stretched in the horizontal direction is 2-4:1, the short diagonal size of the diamond micropores stretched in the horizontal direction is 0.2 mm to 1 mm, and the diagonal size of the square micropores stretched in the horizontal direction is 0.2 mm to 1 mm; the length: width: height ratio of the lattice unit cell obtained by compressing in the horizontal direction is 0.25 to 0. 5:1:1, the length of the lattice unit cell obtained by compression in the horizontal direction is 5mm~10mm, the length ratio of the two diagonal lines of the diamond micropores compressed in the horizontal direction is 0.25~0.5:1, the short diagonal size of the diamond micropores compressed in the horizontal direction is 0.2mm~1mm, and the diagonal size of the square micropores compressed in the horizontal direction is 0.4mm~4mm. The porosity range of the 4D printed bidirectional intelligent temperature control lattice structure is 15%~65%, and the thickness of the lattice structure plate and shell is 1.5mm~4.4mm.

[0012] Furthermore, when the ambient temperature reaches a preset temperature, the lattice structure automatically opens and the coolant can flow out from the lattice openings. When the ambient temperature is lower than the preset temperature, the lattice structure automatically closes. The preset temperature is 80°C to 110°C.

[0013] Furthermore, a method for preparing a 4D printed bidirectional intelligent temperature-controlled lattice structure is prepared and processed using a selective laser melting additive manufacturing process. The specific steps are as follows:

[0014] Step 1: Using 3D design software to design the hole structure process adaptability of the lattice structure and establish a 3D model of the lattice structure;

[0015] Step 2: Slice the lattice structure three-dimensional model established in step 1 using slicing software, and prepare the lattice structure using a selective laser melting additive manufacturing process characterized by low volume energy density and high scanning speed;

[0016] Step 3: The lattice structure obtained in step 2 is quasi-statically compressed in the direction perpendicular to the working surface until the opening is closed and then maintained under pressure. After unloading, the closed-pore lattice structure is heated up and then cooled to room temperature. The above operation is repeated for 15 to 50 cycles to obtain the final 4D printed bidirectional intelligent temperature-controlled lattice structure.

[0017] Furthermore, the low body energy density in step 2 is 26.67 J / mm 3 ~125J / mm 3 , the maximum scanning speed is 800mm / s~1500mm / s; laser power is 100W~300W, scanning interval is 20μm~125μm, scanning angle is 45°~90°, and layer thickness is 20μm~50μm.

[0018] Furthermore, in step three, the pressure of the quasi-static compression is 450 MPa to 750 MPa, the holding time is 10 seconds to 20 seconds, and the temperature is raised to 120° C. to 200° C.

[0019] Furthermore, the matrix material for preparing the 4D printed bidirectional intelligent temperature control lattice structure is nickel-titanium shape memory alloy powder, the mass fraction of nickel element in the nickel-titanium shape memory alloy powder is 54.2% to 54.8%, and the powder particle size is 15 μm to 53 μm.

[0020] Furthermore, the 4D printed bidirectional intelligent temperature control lattice structure is used to prepare high-temperature service components for aerospace vehicles.

[0021] Beneficial effects of the present invention:

[0022] 1. Bidirectional intelligent opening and closing: The present invention combines lattice metal design with shape memory alloy, adopts nickel-titanium alloy powder with a nickel element mass fraction of 54.2-54.8%, utilizes the shape memory effect of nickel-titanium alloy under temperature excitation conditions, and combines the characteristics of selective laser melting additive manufacturing process to integrate the 4D printed bidirectional intelligent temperature-controlled lattice structure. Under temperature excitation conditions, the bidirectional intelligent temperature-controlled lattice structure prepared by the present invention can be intelligently opened and closed, and the coolant can control whether to flow out of the lattice structure openings according to the ambient temperature.

[0023] 2. High preset temperature: The present invention effectively improves the preset temperature of the intelligent temperature-controlled dot matrix switch through alloy composition design and additive manufacturing process control. The preset temperature of the intelligent temperature-controlled bidirectional dot matrix structure switch can be freely adjusted in the range of 80°C to 110°C. This temperature is close to the extreme response temperature of this type of shape memory alloy material, effectively broadening the application scope of nickel-titanium shape memory alloy in the aerospace field.

[0024] 3. Controllable coolant flow rate: The present invention designs an intelligent temperature-controlled bidirectional lattice structure with a smaller opening size. The minimum diagonal size of the model opening is only 0.2mm~1mm. After the additive manufacturing lattice structure is post-processed and formed, the minimum diagonal size of the lattice opening can be intelligently changed within the range of 0mm~1mm according to the ambient temperature. The change in the lattice opening size can effectively control the coolant flow rate, meeting the application requirements of the intelligent temperature-controlled bidirectional lattice structure in the aerospace field.

[0025] 4. Strong Designability: This invention utilizes a selective laser melting additive manufacturing process to produce the intelligent temperature-controlled, bidirectional lattice structure switch. This allows for flexible adjustment of the switch's appearance and morphology to meet specific aerospace and other applications, offering a high degree of design freedom. Furthermore, leveraging the unique characteristics of additive manufacturing, the manufacturing process requires no mold processing and is unconstrained by the alloy system or workpiece shape. This allows for highly flexible molding of complex intelligent temperature-controlled, bidirectional lattice structure switches. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic diagram of the axial side of a unit cell of a 4D printed bidirectional intelligent temperature control lattice structure of Example 1.

[0027] Figure 2 is a schematic diagram of the axial side of a unit cell of the 4D printed bidirectional intelligent temperature control lattice structure of Example 2.

[0028] FIG3 is a schematic diagram of the axial side of a unit cell of a 4D printed bidirectional intelligent temperature control lattice structure of Example 3.

[0029] FIG4 is a schematic diagram of the axial side of a unit cell of a 4D printed bidirectional intelligent temperature control lattice structure of Example 4.

[0030] FIG5 is a schematic diagram of the axial side of a unit cell of a 4D printed bidirectional intelligent temperature control lattice structure of Example 5.

[0031] FIG6 is a front view schematic diagram of a microporous lattice unit cell of Example 1.

[0032] FIG7 is a schematic front view of a microporous lattice unit cell of Example 2.

[0033] FIG8 is a front view schematic diagram of a microporous lattice unit cell of Example 3.

[0034] FIG9 is a schematic front view of a microporous lattice unit cell of Example 4.

[0035] FIG10 is a schematic front view of a microporous lattice unit cell of Example 5.

[0036] FIG11 is a schematic diagram of a 4D printed bidirectional intelligent temperature control lattice structure according to Example 1.

[0037] FIG12 is a schematic diagram of a dot matrix of a 4D-printed bidirectional intelligent temperature control dot matrix structure according to Example 4.

[0038] Figure 13 is the morphology of the 4D printed bidirectional intelligent temperature control lattice structure sample before closure.

[0039] Figure 14 is the morphology of the 4D printed bidirectional intelligent temperature control lattice structure sample after pore closing.

[0040] Figure 15 is the DSC curve of the 4D printed bidirectional intelligent temperature-controlled lattice structure matrix material. DETAILED DESCRIPTION

[0041] The preparation method of the present invention will be described in detail below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention. The lattice structure is an integral structural component prepared by an additive manufacturing process and does not require additional processing steps such as welding.

[0042] A 4D-printed bidirectional intelligent temperature-control lattice structure includes a plurality of microporous lattice cells, which are arrayed and mirrored along the x, y, and z directions to obtain a 4D-printed bidirectional intelligent temperature-control lattice structure; the microporous lattice cells are lattice cells obtained by stretching a truncated octahedron in the horizontal direction or by compressing it in the horizontal direction; the micropores are one of diamond micropores stretched in the horizontal direction, diamond micropores compressed in the horizontal direction, square micropores stretched in the horizontal direction, or square micropores compressed in the horizontal direction; and the truncated octahedron is obtained by truncating a regular octahedron with a hollow interior.

[0043] Example 1

[0044] The 4D printed bidirectional intelligent temperature control lattice structure is prepared using a selective laser melting additive manufacturing process. The specific steps are as follows:

[0045] Step 1. Use three-dimensional design software to design the hole structure process adaptability of the lattice structure and establish a three-dimensional model of the lattice structure; the length: width: height of the lattice unit cell obtained by stretching in the horizontal direction is 2:1:1, and the length of the lattice unit cell obtained by stretching in the horizontal direction is 15 mm. The axial side schematic diagram of the 4D printed bidirectional intelligent temperature control lattice structure unit cell of Example 1 is shown in Figure 1. The length ratio of the two diagonals of the diamond micropores stretched in the horizontal direction is 2:1, the short diagonal size of the diamond micropores stretched in the horizontal direction is 1 mm, and the diagonal size of the square micropores stretched in the horizontal direction is 1 mm. The porosity of the 4D printed bidirectional intelligent temperature control lattice structure is 48%, and the thickness of the lattice structure plate shell is 2 mm. Figure 6 is a front view schematic diagram of the microporous lattice unit cell of Example 1. The microporous lattice unit cell is arrayed and mirrored along the x, y, and z directions to obtain a 4D printed bidirectional intelligent temperature control lattice structure. The lattice schematic diagram of the 4D printed bidirectional intelligent temperature control lattice structure of Example 1 is shown in Figure 11.

[0046] Step 2: Use slicing software to slice the lattice structure three-dimensional model established in step 1, and use the selective laser melting additive manufacturing process characterized by low body energy density and high scanning speed to prepare the lattice structure. The low body energy density is 66.67J / mm 3 The maximum scanning speed was 1200 mm / s, the laser power was 200 W, the scanning interval was 125 μm, the scanning angle was 90°, and the layer thickness was 20 μm. The matrix material for preparing the intelligent temperature-controlled bidirectional lattice structure was nickel-titanium shape memory alloy powder. The nickel mass fraction of the nickel-titanium shape memory alloy was 54.2% to 54.8%, and the powder particle size was 15 μm to 53 μm. The morphology of the 4D-printed bidirectional intelligent temperature-controlled lattice structure sample before pore closure is shown in Figure 13.

[0047] Step 3: The lattice structure obtained in step 2 is subjected to 650 MPa quasi-static compression in the direction perpendicular to the working surface until the opening is closed and then maintained at pressure for 15 seconds. After unloading, the closed-pore lattice structure is heated to 150°C and cooled to room temperature. The above operation is repeated for 40 cycles to obtain the final 4D printed bidirectional intelligent temperature-controlled lattice structure sample after closing the pores, as shown in Figure 14.

[0048] When the ambient temperature of the 4D-printed bidirectional intelligent temperature-controlled lattice structure prepared in this embodiment reaches a preset temperature of 95°C, the openings of the lattice structure automatically open, and the coolant can flow out of the lattice openings. When the ambient temperature is lower than the preset temperature, the openings of the lattice structure automatically close. The DSC curve of the matrix material of the 4D-printed bidirectional intelligent temperature-controlled lattice structure is shown in Figure 15.

[0049] Comparative Example 1

[0050] Compared with Example 1, Comparative Example 1 uses a higher volume energy density and a lower scanning speed, and the higher volume energy density is 160 J / mm 3 , the lower scanning speed is 500 mm / s, and the other experimental parameters are exactly the same as those in Example 1.

[0051] According to the experimental scheme of comparative example 1, when the ambient temperature reaches 45°C, the opening of the 4D printed bidirectional intelligent temperature control lattice structure is automatically opened.

[0052] Comparative Example 2

[0053] Compared with Example 1, the lattice structure of Comparative Example 2 was subjected to only one compression and pore closing treatment.

[0054] Step 3: The lattice structure obtained in step 2 was subjected to 650 MPa quasi-static compression along the direction perpendicular to the working surface until the opening was closed and the pressure was maintained for 15 seconds without subsequent heating and cooling loading cycle treatment. Other experimental parameters and steps were exactly the same as those in Example 1.

[0055] The lattice structure of Comparative Example 2 can slowly open its openings when the ambient temperature rises to a preset temperature of 95°C. However, after cooling to the preset temperature of 95°C, or even below room temperature, the openings of the lattice structure remain unchanged. The openings of the lattice structure cannot be closed during the subsequent heating and cooling processes. The above experimental method cannot obtain a 4D printed bidirectional intelligent temperature-controlled lattice structure.

[0056] Example 2

[0057] The 4D printed bidirectional intelligent temperature control lattice structure is prepared using a selective laser melting additive manufacturing process. The specific steps are as follows:

[0058] Step 1. Use three-dimensional design software to design the hole structure process adaptability of the lattice structure and establish a three-dimensional model of the lattice structure; the length: width: height of the lattice unit cell obtained by stretching in the horizontal direction is 3:1:1, and the length of the lattice unit cell obtained by stretching in the horizontal direction is 5 mm. The axial side schematic diagram of the 4D printed bidirectional intelligent temperature control lattice structure unit cell of Example 2 is shown in Figure 2. The length ratio of the two diagonals of the diamond micropores stretched in the horizontal direction is 3:1, the short diagonal size of the diamond micropores stretched in the horizontal direction is 0.2 mm, and the diagonal size of the square micropores stretched in the horizontal direction is 0.2 mm. The porosity of the 4D printed bidirectional intelligent temperature control lattice structure is 15%, and the thickness of the lattice structure plate shell is 3.5 mm. Figure 7 is a front view schematic diagram of the microporous lattice unit cell of Example 2. The 4D printed bidirectional intelligent temperature control lattice structure is obtained after the microporous lattice unit cell is arrayed and mirrored along the x, y, and z directions.

[0059] Step 2: Use slicing software to slice the lattice structure three-dimensional model established in step 1, and use the selective laser melting additive manufacturing process characterized by low body energy density and high scanning speed to prepare the lattice structure. The low body energy density is 26.67J / mm 3 The maximum scanning speed is 1500 mm / s, the laser power is 100 W, the scanning interval is 50 μm, the scanning angle is 45°, and the layer thickness is 50 μm. The base material for preparing the intelligent temperature-controlled bidirectional lattice structure is nickel-titanium shape memory alloy powder. The nickel mass fraction of the nickel element in the nickel-titanium shape memory alloy is 54.2% to 54.8%, and the powder particle size is 15 μm to 53 μm.

[0060] Step 3: The lattice structure obtained in step 2 is subjected to quasi-static compression at 450 MPa in the direction perpendicular to the working surface until the opening is closed and then maintained at pressure for 10 seconds. After unloading, the closed-pore lattice structure is heated to 120°C, cooled to room temperature, and the above operation is repeated for 15 cycles to obtain the final bidirectional intelligent temperature-controlled lattice structure.

[0061] When the ambient temperature of the 4D printed bidirectional intelligent temperature control lattice structure prepared in this embodiment reaches a preset temperature of 80°C, the opening of the lattice structure automatically opens, and the coolant can flow out from the lattice opening. When the ambient temperature is lower than the preset temperature, the opening of the lattice structure automatically closes.

[0062] Example 3

[0063] The 4D printed bidirectional intelligent temperature control lattice structure is prepared using a selective laser melting additive manufacturing process. The specific steps are as follows:

[0064] Step 1. Use three-dimensional design software to design the hole structure process adaptability of the lattice structure and establish a three-dimensional model of the lattice structure; for the lattice unit cell obtained by stretching in the horizontal direction, the length: width: height is 4:1:1, and the length of the lattice unit cell obtained by stretching in the horizontal direction is 30 mm. The axial side schematic diagram of the 4D printed bidirectional intelligent temperature control lattice structure unit cell of Example 3 is shown in Figure 3. The diagonal size of the square micropores stretched in the horizontal direction is 4:1, the short diagonal size of the diamond micropores stretched in the horizontal direction is 0.5 mm, and the diagonal size of the square micropores on the surface of the unit cell is 0.5 mm. The porosity of the 4D printed bidirectional intelligent temperature control lattice structure is 65%, and the thickness of the lattice structure plate shell is 4.4 mm. Figure 8 is a front view schematic diagram of the microporous lattice unit cell of Example 3. The 4D printed bidirectional intelligent temperature control lattice structure is obtained by arraying and mirroring the microporous lattice unit cell along the x, y, and z directions.

[0065] Step 2: Use slicing software to slice the lattice structure three-dimensional model established in step 1, and use the selective laser melting additive manufacturing process characterized by low body energy density and high scanning speed to prepare the lattice structure. The low body energy density is 125J / mm 3 , with a maximum scanning speed of 1000 mm / s. Other process parameters include a laser power of 100W, a scanning interval of 20μm, a scanning angle of 67°, and a layer thickness of 40μm. The matrix material for preparing the intelligent temperature-controlled bidirectional lattice structure is a nickel-titanium shape memory alloy powder, in which the mass fraction of nickel in the nickel-titanium shape memory alloy is 54.2% to 54.8%, and the powder particle size is 15μm to 53μm.

[0066] Step 3: The lattice structure obtained in step 2 is subjected to 750 MPa quasi-static compression in the direction perpendicular to the working surface until the opening is closed and the pressure is maintained for 20 seconds. After unloading, the closed-pore lattice structure is heated to 200°C, cooled to room temperature, and the above operation is repeated for 50 cycles to obtain the final bidirectional intelligent temperature-controlled lattice structure.

[0067] When the ambient temperature of the 4D printed bidirectional intelligent temperature control lattice structure prepared in this embodiment reaches a preset temperature of 110°C, the opening of the lattice structure automatically opens, and the coolant can flow out from the lattice opening. When the ambient temperature is lower than the preset temperature, the opening of the lattice structure automatically closes.

[0068] Example 4

[0069] The 4D printed bidirectional intelligent temperature control lattice structure is prepared using a selective laser melting additive manufacturing process. The specific steps are as follows:

[0070] Step 1. Use three-dimensional design software to design the hole structure process adaptability of the lattice structure and establish a three-dimensional model of the lattice structure; for the lattice unit cell obtained by compression in the horizontal direction, the length: width: height is 0.25:1:1, and the length of the lattice unit cell obtained by compression in the horizontal direction is 5 mm. The axial side schematic diagram of the 4D printed bidirectional intelligent temperature control lattice structure unit cell of Example 4 is shown in Figure 4. The diagonal size of the square micropores compressed in the single horizontal direction is 0.25:1, and the short diagonal size of the diamond micropores compressed in the horizontal direction is 1 mm. The diagonal size of the square micropores on the surface of the unit cell is 4 mm. The porosity of the 4D printed bidirectional intelligent temperature control lattice structure is 42%, and the thickness of the lattice structure plate shell is 1.5 mm. Figure 9 is a front view schematic diagram of the microporous lattice unit cell of Example 4. The lattice schematic diagram of the 4D printed bidirectional intelligent temperature control lattice structure obtained after the microporous lattice unit cell is arrayed and mirrored along the x, y, and z directions is shown in Figure 12.

[0071] Step 2: Use slicing software to slice the lattice structure three-dimensional model established in step 1, and use the selective laser melting additive manufacturing process characterized by low body energy density and high scanning speed to prepare the lattice structure. The low body energy density is 75J / mm 3 The maximum scanning speed is 800 mm / s, the laser power is 300 W, the scanning interval is 100 μm, the scanning angle is 90°, and the layer thickness is 50 μm. The base material for preparing the intelligent temperature-controlled bidirectional lattice structure is nickel-titanium shape memory alloy powder. The nickel mass fraction of the nickel element in the nickel-titanium shape memory alloy is 54.2% to 54.8%, and the powder particle size is 15 μm to 53 μm.

[0072] Step 3: The lattice structure obtained in step 2 is subjected to quasi-static compression at 700 MPa in the direction perpendicular to the working surface until the opening is closed and then maintained at pressure for 18 seconds. After unloading, the closed-pore lattice structure is heated to 180°C, cooled to room temperature, and the obtained lattice structure is repeated for 45 cycles to obtain the final bidirectional intelligent temperature-controlled lattice structure.

[0073] When the ambient temperature of the 4D printed bidirectional intelligent temperature-controlled lattice structure prepared in this embodiment reaches a preset temperature of 85°C, the opening of the lattice structure automatically opens, and the coolant can flow out from the lattice opening. When the ambient temperature is lower than the preset temperature, the opening of the lattice structure automatically closes.

[0074] Example 5

[0075] The 4D printed bidirectional intelligent temperature control lattice structure is prepared using a selective laser melting additive manufacturing process. The specific steps are as follows:

[0076] Step 1. Use three-dimensional design software to design the hole structure process adaptability of the lattice structure and establish a three-dimensional model of the lattice structure; for the lattice unit cell obtained by compression in the horizontal direction, the length: width: height is 0.5:1:1, and the length of the lattice unit cell obtained by compression in the horizontal direction is 10 mm. The axial side schematic diagram of the 4D printed bidirectional intelligent temperature control lattice structure unit cell of Example 5 is shown in Figure 5. The short diagonal size of the diamond micropores compressed in the horizontal direction is 0.5:1, and the short diagonal size of the diamond micropores compressed in the horizontal direction is 0.2 mm. The diagonal size of the square micropores on the surface of the unit cell is 0.4 mm. The porosity of the 4D printed bidirectional intelligent temperature control lattice structure is 63%, and the thickness of the lattice structure plate shell is 4.2 mm. Figure 10 is a front view schematic diagram of the microporous lattice unit cell of Example 5. The 4D printed bidirectional intelligent temperature control lattice structure is obtained by arraying and mirroring the microporous lattice unit cell along the x, y, and z directions.

[0077] Step 2: Use slicing software to slice the lattice structure three-dimensional model established in step 1, and use the selective laser melting additive manufacturing process characterized by low body energy density and high scanning speed to prepare the lattice structure. The low body energy density is 85.23J / mm 3 The maximum scanning speed is 1100 mm / s, the laser power is 150 W, the scanning interval is 80 μm, the scanning angle is 75°, and the layer thickness is 20 μm. The base material for preparing the intelligent temperature-controlled bidirectional lattice structure is nickel-titanium shape memory alloy powder. The nickel mass fraction of the nickel element in the nickel-titanium shape memory alloy is 54.2% to 54.8%, and the powder particle size is 15 μm to 53 μm.

[0078] Step 3: The lattice structure obtained in step 2 is subjected to quasi-static compression at 750 MPa in the direction perpendicular to the working surface until the opening is closed and the pressure is maintained for 20 seconds. After unloading, the closed-pore lattice structure is heated to 120°C, cooled to room temperature, and the above operation is repeated for 50 cycles to obtain the final bidirectional intelligent temperature-controlled lattice structure.

[0079] When the ambient temperature of the 4D printed bidirectional intelligent temperature control lattice structure prepared in this embodiment reaches a preset temperature of 90°C, the opening of the lattice structure automatically opens, and the coolant can flow out from the lattice opening. When the ambient temperature is lower than the preset temperature, the opening of the lattice structure automatically closes.

[0080] Example 6

[0081] The 4D printed bidirectional intelligent temperature control lattice structure is prepared using a selective laser melting additive manufacturing process. The specific steps are as follows:

[0082] Step 1. Use three-dimensional design software to design the hole structure process adaptability of the lattice structure and establish a three-dimensional model of the lattice structure; the length: width: height of the lattice unit cell obtained by compression in the horizontal direction is 0.4:1:1, the length size of the lattice unit cell obtained by compression in the horizontal direction is 8mm, the short diagonal size of the diamond micropores compressed in the horizontal direction is 0.4:1, the short diagonal size of the diamond micropores compressed in the horizontal direction is 0.4mm, the diagonal size of the square micropores on the unit cell surface is 1mm, the porosity of the 4D printed bidirectional intelligent temperature control lattice structure is 55%, the thickness of the lattice structure plate and shell is 3.5mm, and the microporous lattice unit cell is arrayed and mirrored along the x, y, and z directions to obtain a 4D printed bidirectional intelligent temperature control lattice structure.

[0083] Step 2: Use slicing software to slice the lattice structure three-dimensional model established in step 1, and use the selective laser melting additive manufacturing process characterized by low body energy density and high scanning speed to prepare the lattice structure. The low body energy density is 66.67J / mm 3The maximum scanning speed is 1000 mm / s, the laser power is 200W, the scanning interval is 100 μm, the scanning angle is 55°, and the layer thickness is 30 μm. The base material for preparing the intelligent temperature-controlled bidirectional lattice structure is nickel-titanium shape memory alloy powder. The nickel mass fraction of the nickel element in the nickel-titanium shape memory alloy is 54.2% to 54.8%, and the powder particle size is 15 μm to 53 μm.

[0084] Step 3: The lattice structure obtained in step 2 is subjected to 450 MPa quasi-static compression in the direction perpendicular to the working surface until the opening is closed and the pressure is maintained for 10 seconds. After unloading, the closed-pore lattice structure is heated to 200°C, cooled to room temperature, and the obtained lattice structure is repeated for 15 cycles to obtain the final bidirectional intelligent temperature-controlled lattice structure.

[0085] When the ambient temperature of the 4D printed bidirectional intelligent temperature control lattice structure prepared in this embodiment reaches a preset temperature of 95°C, the opening of the lattice structure automatically opens, and the coolant can flow out from the lattice opening. When the ambient temperature is lower than the preset temperature, the opening of the lattice structure automatically closes.

[0086] Matters not covered by the present invention are known technologies.

[0087] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A 4D printing bidirectional intelligent temperature control lattice structure, characterized in that: The 4D printed bidirectional intelligent temperature control lattice structure includes a plurality of microporous lattice cells, which are arrayed and mirrored along the x, y, and z directions to obtain a 4D printed bidirectional intelligent temperature control lattice structure; the microporous lattice cell is a lattice cell obtained by stretching a truncated octahedron in the horizontal direction or a lattice cell obtained by compressing it in the horizontal direction, and the micropores are one of diamond micropores stretched in the horizontal direction, diamond micropores compressed in the horizontal direction, square micropores stretched in the horizontal direction, or square micropores compressed in the horizontal direction. The truncated octahedron is obtained by truncating a regular octahedron with a hollow interior; when the ambient temperature reaches a preset temperature, the lattice structure automatically opens, and the coolant can flow out from the lattice opening. When the ambient temperature is lower than the preset temperature, the lattice structure automatically closes, and the preset temperature is 80°C to 110°C. The 4D printed bidirectional intelligent temperature control lattice structure is prepared and processed using a selective laser melting additive manufacturing process. The specific steps are as follows: Step 1: Using 3D design software to design the hole structure process adaptability of the lattice structure and establish a 3D model of the lattice structure; Step 2: Slice the lattice structure three-dimensional model established in step 1 using slicing software, and prepare the lattice structure using a selective laser melting additive manufacturing process characterized by low volume energy density and high scanning speed; Step 3: The lattice structure obtained in step 2 is quasi-statically compressed in a direction perpendicular to the working surface until the pores are closed and then maintained under pressure. After unloading, the closed-pore lattice structure is heated up and then cooled to room temperature. The above operation is repeated for 15 to 50 cycles to obtain the final 4D printed bidirectional intelligent temperature-controlled lattice structure. The low body energy density in step 2 is 26.67 J / mm 3 ~125J / mm 3 , the maximum scanning speed is 800mm / s~1500mm / s; The laser power is 100W to 300W, the scanning interval is 20μm to 125μm, the scanning angle is 45° to 90°, and the layer thickness is 20μm to 50μm. The base material for preparing the 4D printed bidirectional intelligent temperature control lattice structure is nickel-titanium shape memory alloy powder, the mass fraction of nickel element in the nickel-titanium shape memory alloy powder is 54.2% to 54.8%, and the powder particle size is 15μm to 53μm.

2. The 4D printing bidirectional intelligent temperature control lattice structure according to claim 1, characterized in that: The length, width and height of the lattice unit cell obtained by stretching in the horizontal direction are 2-4:1:1, the length of the lattice unit cell obtained by stretching in the horizontal direction is 5mm-30mm, the length ratio of the two diagonal lines of the diamond micropores stretched in the horizontal direction is 2-4:1, the short diagonal size of the diamond micropores stretched in the horizontal direction is 0.2mm-1mm, and the diagonal size of the square micropores stretched in the horizontal direction is 0.2mm-1mm; the length, width and height of the lattice unit cell obtained by compressing in the horizontal direction are 0.25-0.5: 1:1, the length of the lattice unit cell obtained by compression in the horizontal direction is 5mm~10mm, the length ratio of the two diagonal lines of the diamond micropores compressed in the horizontal direction is 0.25~0.5:1, the short diagonal size of the diamond micropores compressed in the horizontal direction is 0.2mm~1mm, and the diagonal size of the square micropores compressed in the horizontal direction is 0.4mm~4mm. The porosity range of the 4D printed bidirectional intelligent temperature control lattice structure is 15%~65%, and the thickness of the lattice structure plate and shell is 1.5mm~4.4mm.

3. The 4D printing bidirectional intelligent temperature control lattice structure according to claim 1, characterized in that: In step three, the pressure of the quasi-static compression is 450 MPa to 750 MPa, the holding time is 10 seconds to 20 seconds, and the temperature is raised to 120° C. to 200° C.

4. An application of a 4D printed bidirectional intelligent temperature control lattice structure, using the 4D printed bidirectional intelligent temperature control lattice structure according to claim 1, characterized in that: The 4D printed bidirectional intelligent temperature control lattice structure is used to prepare high-temperature service components for aerospace vehicles.

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