A high-pressure-bearing three-dimensional interconnected multi-level pore structure and its preparation method

Abstract

The present invention relates to a high-pressure-bearing three-dimensional interconnected multi-level pore structure and a preparation method thereof, including: a plurality of elementary cells, each elementary cell including a vertical enclosure and a horizontal enclosure. Horizontal enclosures are provided between the upper and lower parts of the tube walls of adjacent two vertical enclosures, and notches are provided on both the upper and lower sides of the middle of each horizontal enclosure; the central angle corresponding to each horizontal enclosure is 90°; the elementary cells are spliced with each other to form a three-dimensional interconnected multi-level pore structure. The beneficial effects of the present invention are: holes provided on the outer wall of the channels of the three-dimensional interconnected multi-level pore structure and multi-level pore structures of different sizes formed by the enclosure of each channel; while reducing the weight of the three-dimensional structure, this structure has both the structural function of bearing axial load and the material transmission function. When a path needs to be provided for material migration, this porous structure promotes the inward migration and infiltration of materials in the pores, and at the same time ensures its high mechanical properties. Therefore, it can be widely used in various fields such as aerospace and biomedicine.

Description

Technical Field

[0001] The present invention belongs to the technical field of structural design, and particularly relates to a high-pressure-bearing three-dimensional connected multi-level pore structure and a preparation method thereof. Background Art

[0002] Tension, compression, shear, torsion, and bending are conventional stress modes in engineering applications. Among them, while achieving weight reduction and light weight, improving the compressive bearing capacity is the scene requirement of specific engineering applications such as aviation, aerospace, and transportation. Compared with a dense solid structure, as one of the effective ways to achieve lightweight design, a porous structure can reduce the elastic modulus of the material, avoid the generation of stress shielding effects, and at the same time further reduce the mass, save materials, and reduce costs. However, if the pore diameter of the porous structure is set too small, it will hinder the diffusion rate of the medium, and for the transmission of substances with larger-sized molecules, a single pore size system will prevent molecules from entering its pores, and even the diffusion path of the molecules entering the pores will be restricted, causing loss or blockage to the porous structure, greatly reducing the medium transportation efficiency, adsorption efficiency, adsorption capacity, etc.

[0003] In practical applications, the existence of a multi-level pore structure is beneficial to reducing the mass transfer resistance of substance molecules, increasing the mass transfer rate, shortening their diffusion paths inside the porous structure, enabling media of different scales to diffuse or adsorb quickly, and facilitating the exchange and transportation between different media. In addition, using a porous structure in the field of biomedicine can also obtain a porous implant similar to human bone in mechanical properties, and when pores of different sizes of millimeters and micrometers are combined, it is also beneficial to the growth of osteoblasts. Therefore, the multi-level pore structure is also a good matching structure for the biomedical implantation process.

[0004] However, with the increase in porosity, although the existence of multi-level pores reduces the structural modulus and improves the mass transfer efficiency of substances, it will also significantly weaken the mechanical properties of the material, and its compressive strength will decrease exponentially, and the two cannot simultaneously meet the usage requirements of high bearing capacity and lightweight application scenarios.

[0005] In addition, in order to ensure the efficient transmission of substances, the porous structure is mostly designed as a lattice structure composed of multiple rods, and the unit cells of its lattice are mostly symmetric structures connected by rods. When stressed, the rods bend, and stress concentration is likely to occur at their junctions. Therefore, the material utilization rate is not high, and the high specific stiffness and specific strength characteristics of the lattice porous structure cannot be fully utilized, and the bearing capacity is poor.

[0006] Therefore, designing and constructing a multi-level pore structure with diverse functions such as high-efficiency bearing and fluid mass transfer is of great significance for realizing the lightweight of high-bearing structures. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a high-pressure-bearing three-dimensional connected multi-level pore structure and a preparation method thereof.

[0008] This high-pressure-bearing three-dimensional connected multi-level pore structure includes: a number of elementary cells, each elementary cell including a vertical enclosure and a horizontal enclosure. A horizontal enclosure is provided between the upper and lower parts of the tube walls of two adjacent vertical enclosures, and notches are provided on both the upper and lower sides of the middle of the horizontal enclosure; the central angle corresponding to each horizontal enclosure is 90°;

[0009] The elementary cells are spliced with each other to form a three-dimensional connected multi-level pore structure. The three-dimensional connected multi-level pore structure includes a crossbeam channel and a column channel. The crossbeam channel and the column channel are hollow inside. Four holes are circumferentially opened in the middle of each crossbeam channel, and the holes are formed by splicing the notches in the middle of the horizontal arc-shaped plates; the two ends of each crossbeam channel are vertically connected to the side walls of the column channel, and the upper and lower ends of the column channel are through; the crossbeam channel and the column channel enclose to form a cavity on the plane, and several cavities in the three-dimensional connected multi-level pore structure communicate with each other;

[0010] The crossbeam channel, the column channel, the holes in the middle of the crossbeam channel and the cavity constitute a multi-level pore structure.

[0011] Preferably: each elementary cell includes four or six vertical enclosures, and the horizontal enclosures in each elementary cell enclose a square, a rectangle or a hexagon on the horizontal plane; when each elementary cell includes four vertical enclosures, the central angle corresponding to each vertical enclosure is 90°; when each elementary cell includes six vertical enclosures, the central angle corresponding to each vertical enclosure is 120°.

[0012] Preferably: cavities are enclosed between the crossbeam channels, and the cavities are square, rectangular or hexagonal. A circumferential cavity is enclosed by two adjacent column channels and the two crossbeam channels connected thereto, and the circumferential cavity is square or rectangular.

[0013] Preferably: four vertical enclosures are provided in each elementary cell, and support plates are provided on the vertical enclosures. The two end faces of the support plates are respectively connected to the two end faces of the vertical enclosures; the support plates are folded plates or arc-shaped folded plates, and cross-plate supports are provided longitudinally in the column channels of the three-dimensional connected multi-level pore structure formed by splicing the elementary cells.

[0014] Preferably: the side length of a single elementary cell is less than 10 mm, and the thickness of the vertical enclosures and the horizontal enclosures in the elementary cell is 0.1 - 0.75 mm; the diameter of each level of pores in the multi-level pore structure is greater than or equal to 18 μm.

[0015] Preferably: by replacing the vertical enclosures and the horizontal enclosures with flat plates with pore structures, the three-dimensional connected multi-level pore structure formed by splicing the elementary cells is composed of vertical flat plates and horizontal flat plates.

[0016] The preparation method of this high-pressure-bearing three-dimensional connected multi-level pore structure includes the following steps:

[0017] Step 1: Edit and design basic cells through modeling software;

[0018] Step 2: As needed, the basic cells obtained in step 1 are arrayed in the modeling software to expand into a three-dimensional interconnected multi-level pore structure;

[0019] Step 3: Slice the established 3D model and set the printing trajectory;

[0020] Step 4: The three-dimensional interconnected multi-level pore structure is manufactured layer by layer through a material jetting or powder bed fusion 3D printing system until a final formed blank is obtained by printing.

[0021] Preferably, in step 2: after the basic cell array is formed into a three-dimensional interconnected multi-level hole structure as needed, the outermost layer of the three-dimensional interconnected multi-level hole structure is completed so that all vertical enclosures and horizontal enclosures are spliced ​​into complete beam channels and column channels.

[0022] The beneficial effects of the present invention are:

[0023] 1. The three-dimensional interconnected multi-level pore structure provided by the present invention is composed of a plurality of cubic-based cell arrays. When subjected to load, a plurality of hollow channels are deformed simultaneously, and the load can be borne by a plurality of hollow structure beams and columns. At the same time, a cross plate support is arranged inside the column pipe. Compared with a lattice structure of the same mass connected by rods or plates, its stress distribution is more uniform, and it also has better mechanical properties, especially in modulus, strength and energy absorption.

[0024] 2. The holes arranged on the outer wall of the three-dimensional interconnected multi-level pore structure channel and the multi-level pore structure of different sizes formed by the channels in the present invention; this structure has both the structural function of bearing axial load and the function of transmitting substances while reducing the weight of the three-dimensional structure. When it is necessary to provide a path for the migration of substances, the porous structure promotes the migration and infiltration of substances in the pores, while ensuring that it has high mechanical properties. Therefore, it can be widely used in various fields such as aerospace or biomedicine.

[0025] 3. The present invention adopts material injection or powder bed fusion molding technology to prepare a high-pressure three-dimensional interconnected multi-level pore structure with a porosity of 60% to 90%. The shape, porosity, and pore size of the product are precisely controllable, and the precise preparation of porous materials can be completed based on actual needs; the preparation process is simple, and porous block materials with a size range from tens of microns to hundreds of centimeters can be produced, which is suitable for large-scale industrial production requirements. At the same time, especially for components that need to meet multi-scale medium transmission and high-pressure application scenarios at the same time, the multi-level pore structure of the present invention can be in long-term and stable service. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1aA primitive cell structure of the present invention;

[0027] Figure 1b is Figure 1a a three-dimensional connected multi-level pore structure formed by a corresponding simple array;

[0028] Figure 1c is Figure 1b the top view of;

[0029] Figure 1d is Figure 1c the sectional view of;

[0030] Figure 2 a ceramic solid model of the Figure 1b structure printed by the material jetting method.

[0031] Figure 3a Another unit cell structure of the present invention without a cross-plate support at the center of the radial column;

[0032] Figure 3b is Figure 3a a three-dimensional connected multi-level pore structure formed by a corresponding simple array;

[0033] Figure 3c is Figure 3b the top view of;

[0034] Figure 3d is Figure 3c the sectional view of;

[0035] Figure 4 a ceramic solid model of the Figure 3b structure printed by the material jetting method;

[0036] Figure 5 A schematic diagram of design parameters corresponding to a primitive cell structure of the present invention;

[0037] Figure 6 The ultimate pressure curve of a primitive cell structure of the present invention under different relative densities.

[0038] Explanation of reference numerals: Vertical enclosure 1, support plate 11, horizontal enclosure 2, column channel 3, cross-plate support 31, beam channel 4, hole 41. Detailed implementation manners

[0039] The present invention will be further described below in conjunction with embodiments. The description of the following embodiments is only for helping to understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0040] Embodiment 1

[0041] As an example, Figures 1a to 5 As shown, a high-pressure three-dimensional interconnected multi-level hole structure includes: a plurality of elementary cells, the elementary cells include a vertical enclosure 1 and a horizontal enclosure 2, a horizontal enclosure 2 is provided between the upper and lower parts of two adjacent vertical surface pipe walls, and notches are provided on the upper and lower sides of the middle of the horizontal enclosure 2; the central angle corresponding to each horizontal enclosure 2 is 90°;

[0042] Each primitive cell includes four or six vertical panels 1, and the horizontal panels 2 in each primitive cell are combined on the horizontal plane to form a square, rectangle or hexagon; when each primitive cell includes four vertical panels 1, the central angle corresponding to each vertical panel 1 is 90°; when each primitive cell includes six vertical panels 1, the central angle corresponding to each vertical panel 1 is 120°.

[0043] When the transverse enclosures 2 in each primitive cell are enclosed on the horizontal plane to form a square or rectangle, four vertical enclosures 1 are provided in each primitive cell, and a support plate 11 can also be provided on the vertical enclosure 1 corresponding to the column channel 3 of the primitive cell, and the two end faces of the support plate 11 are respectively connected to the two end faces of the surface structure; the column channel 3 of the three-dimensional interconnected multi-level hole structure formed by splicing the primitive cells is provided with a cross plate support 31 throughout the length, and the cross plate support 31 can be a cross-shaped, cross-flat plate, or a plate with an arc, such as a fan-shaped curved cross structure.

[0044] The vertical enclosure 1 and the horizontal enclosure 2 may also be replaced by a flat plate with a porous structure, so that the three-dimensional interconnected multi-level pore structure formed by splicing the basic cells is composed of the vertical flat plate and the horizontal flat plate.

[0045] The elementary cells are spliced ​​together to form a three-dimensional interconnected multi-level hole structure, which includes a beam channel 4 and a column channel 3. The beam channel 4 and the column channel 3 are hollow inside, and four holes 41 are opened in the middle of each section of the beam channel 4 in a circumferential direction. The holes 41 are formed by splicing the notches in the middle of the transverse enclosure 2; the two ends of each section of the beam channel 4 are vertically connected to the side walls of the column channel 3, and the upper and lower ends of the column channel 3 are connected; the beam channel 4 and the column channel 3 are enclosed to form a cavity on the plane, and several cavities in the three-dimensional interconnected multi-level hole structure are connected to each other. The cross-sectional shape of the beam channel 4 and the column channel 3 is not limited to a circle, but can also be a polygon, specifically a centrally symmetrical shape, as long as it can be obtained by splicing elementary cells. Therefore, the shape of the vertical enclosure 1 and the transverse enclosure 2 is not limited to an arc plate, but can also be a folded plate.

[0046] A hole may also be opened at the junction of the column channel 3 and the beam channel 4 to connect the column channel 3 and the beam channel 4 to form a right-angle interconnected pore structure that is interconnected and has a porosity of 60-90%.

[0047] An upper and lower cavity is formed by enclosing between the crossbeam channels 4. The upper and lower cavities are square, rectangular or hexagonal. An adjacent pair of column channels 3 and the two crossbeam channels 4 connected thereto enclose a circumferential cavity, and the circumferential cavity is square or rectangular. The three-dimensional connected multi-level pore structure is provided with pores in the micron scale. The side length of a single unit cell is less than 10 mm, and the thickness of the vertical baffles 1 and the horizontal baffles 2 in the unit cell is 0.1 - 0.75 mm; the diameter of each level of pores in the multi-level pore structure is greater than or equal to 18 μm.

[0048] The crossbeam channels 4, the column channels 3, the holes 41 in the middle of the crossbeam channels 4 and the cavities constitute a multi-level pore structure. It can meet the requirements of multi-scale medium transfer. At the same time, the high pressure-bearing capacity of its structure can perfectly match the structural components used in the compressed state. For example, in the medical implantation fields such as the hip joint and dental implants in the human body, the micron-scale pore diameter is beneficial to cell differentiation in the early stage of implantation, facilitating the rapid formation of bone tissue and effectively reducing the stress shielding at the interface; while the millimeter-scale pore diameter is more conducive to the transfer of nutrients and the proliferation of bone cells in the middle and late stages of implantation, promoting the rapid growth of bone tissue. The three-dimensional connected multi-level pore structure of the present invention can perfectly match the requirements of multi-scale medium transfer. At the same time, the high pressure-bearing capacity of its structure can provide guarantee for patients in the early stage of implantation, and has good biocompatibility and mechanical compatibility.

[0049] The purpose of the present invention is to provide a three-dimensional connected multi-level pore structure with both high pressure-bearing and multi-scale medium transfer capabilities. This structure can solve the problem that the existing porous structures cannot simultaneously meet the dual requirements of high strength and multi-scale medium fluidity, and has good applicability especially for the mass transfer structural components used in the compressed state.

[0050] This porous structure is expanded from a cubic structure with multi-level pore units as the internal unit cells. Each unit cell is composed of a plurality of crossbeam channels 4 and column channels 3 containing hollow channels. Among them, the column channels 3 or the plate members are the main pressure-bearing components, and the crossbeam channels 4 or the plate members are the lateral force-bearing components and play a mutual support role with the radial components. Considering that the structure of the present invention mainly bears pressure, the stability of the compressed components will play a decisive role in the load-bearing capacity of the overall structure. Combining with Euler's formula, the critical pressure of an ideal compressed rod is:

[0051]

[0052] In the formula: F cr is the critical bearing capacity of the compressed rod; E is the elastic modulus of the material; I is the moment of inertia of the cross-section, representing the flexural rigidity of the cross-section; l is the length of the compressed rod; μ is the calculated length coefficient, representing the support situation of the rod. The stronger the support, the smaller the value. For example, when both ends are fixed, it takes 0.5, and when both ends are hinged, it takes 1.0.

[0053] As known from Euler's formula, when the material is fixed, the critical pressure of a compression bar is directly proportional to its sectional flexural rigidity and inversely proportional to its calculated length. That is, the stronger the flexural capacity of the compression bar and the shorter its length, the greater its critical buckling load. Based on this, in the present invention, the slender compression member, namely the column channel 3, is divided through the mutual support of the crossbeam channel 4 and the column channel 3, greatly reducing its calculated length. And through the additive manufacturing integrated forming technology, the support strength of the through node is ensured, and the value of its calculated length coefficient is reduced. At the same time, the column channel 3 adopts a hollow form to effectively improve its sectional flexural efficiency, and a cross plate is additionally arranged inside to further strengthen the flexural performance in two main axis directions, effectively enhancing the overall stability of the compression bar and preventing local buckling of the thin-walled compression member, thereby improving the compression bearing capacity of the overall structure.

[0054] Embodiment 2

[0055] As another embodiment, for the high-pressure-bearing three-dimensional connected multi-level pore structure in Embodiment 1, the precise forming of its multi-level pores in the micron scale and the strength requirements of integrated forming pose very high requirements on the forming process of the multi-level pore structure. Therefore, the additive manufacturing process based on the material jetting technology in the present invention can precisely control the forming of a multi-level pore structure with a size of ten microns, effectively realizing the medium transfer ability of the three-dimensional connected multi-level pore structure, weakening its stress shielding effect, and making it meet the performance requirements such as mechanical strength and medium transfer in the application scenario.

[0056] Specifically, it includes the following steps:

[0057] Step 1: Design the model of the three-dimensional connected multi-level pore structure by using modeling software, and edit the primitive cell of the porous structure according to the cubic configuration.

[0058] Step 2: Expand the primitive cell into the required product shape; and set the minimum size that can be precisely printed for each level of pore structure and the wall thickness of each channel to 18 μm.

[0059] Step 3: Perform slicing processing on the established three-dimensional model and set the printing trajectory.

[0060] Step 4: Adopt a material jetting 3D printing system to layer-by-layer manufacture the three-dimensional connected multi-level pore structure until the final formed blank is printed.

[0061] The printing accuracy of the material jetting technology adopted is 5-10 μm. Compared with the porous materials prepared by traditional methods such as adding pore-forming agents, foaming method, freeze-drying, etc., they have low porosity, difficult control of pore size and pore channel penetration rate, single pore structure, and relatively poor mechanical properties. This method can manufacture multi-scale porous materials with both micro and macro porosity, realizing controllable pore size, controllable pore channel structure, and a three-dimensional porous implant structure with completely connected internal pore channels. Moreover, its support material is a water-soluble material, and the support material inside the three-dimensional connected multi-level pore structure is easy to remove, which can not only improve material utilization rate, save time, and reduce costs, but also has the advantages of high efficiency, high precision, and rapid prototyping.

[0062] The above green body is degreased and sintered by using a sintering furnace, and finally a product with a three-dimensional connected multi-level pore structure is obtained through post-treatment.

[0063] Example Three

[0064] As another example, the preparation process of the high-pressure-bearing three-dimensional connected multi-level pore structure according to Example Two is as follows:

[0065] Taking the slurry containing 3Y-TZP zirconia nanoparticle powder with a diameter of 40 nm as the raw material, the primitive cell structure designed by the modeling software is shown in Figure 1a .

[0066] The side length of this primitive cell is 10 mm, the radius r1 of the vertical enclosing plate 1 is 2.5 mm, the wall thickness is 0.75 mm, the thickness of the support plate 11 is 0.35 mm, the thickness t3 of the cross-shaped support 31 formed after splicing is 0.7 mm, the radius r2 of the horizontal enclosing plate 2 is 2 mm, the wall thickness is 0.3 mm, the shape of the notch symmetrically arranged on the outer wall of the horizontal enclosing plate 2 is semi-circular, and its radius r3 is 0.8 mm.

[0067] After expanding this primitive cell by array, a Figure 1b porous structure is formed. The other levels of pore structures are shown in Figure 1c and Figure 1d . The pore sizes are as follows: the length and width dimensions of the rectangular cavity at A are 2.5 mm and 4 mm respectively, the inscribed circle size of the cavity at B is 3.9 mm, and the inscribed circle diameter of the fan-shaped pore C in the column pore channel is 1 mm.

[0068] Use a material jetting printer to prepare a three-dimensional connected multi-level pore structure material, set the layer thickness to 8 μm, and print layer by layer until the final green body is formed. Keep it in a drying oven at 70 °C for 20-30 min for drying treatment; then keep the printed green body at 1400 °C for 1-3 h to obtain the final sintered product as shown in Figure 2 .

[0069] The porosity of the prepared three-dimensional interconnected multi-level pore structure of zirconia is 64%, and the average density is 2.21 g / cm 3 .

[0070] In this embodiment, the three-dimensional interconnected multi-level pore structure made of zirconia has a compressive strength of 750 MPa.

[0071] Example 4

[0072] As another example, the preparation process of the high-pressure-bearing three-dimensional interconnected multi-level pore structure according to Example 2 is as follows:

[0073] Taking the slurry containing 3Y-TZP zirconia nanoparticle powder with a diameter of 40 nm as the raw material, the primitive cell structure designed by the modeling software is shown in Figure 3a , that is, the primitive cell without the support plate 11.

[0074] The side length of this primitive cell is 10 mm, the diameter of the vertical baffle 1 is 4 mm, and the wall thickness is 0.3 mm. After splicing, there is no cross-plate support 31 in the center of the column channel 3 formed. The axial pore diameter of the horizontal baffle 2 is 4 mm, and the wall thickness is 0.25 mm. The shapes of the symmetrically arranged notches on the upper and lower outer walls of the horizontal baffle 2 are semi-circular, and their diameter is 1.6 mm.

[0075] After expanding the primitive cell by array, a Figure 3b porous structure is formed. The other levels of pore structures are shown in Figure 3c and Figure 3d . The pore diameters are as follows: the cavity size of the square pore at A is 4 mm, and the cavity at B is also a square cavity with a side length of 4 mm.

[0076] Using a material jet printing machine to prepare the three-dimensional interconnected multi-level pore structure material, the layer thickness is set to 8 μm, and printing is carried out layer by layer until the final green body is formed. Further, the printed green body is kept in a drying oven at 70 °C for 20 - 30 min for drying treatment; then the printed green body is heat-preserved at 1400 °C for 1 - 3 h to obtain the final sintered product shown in Figure 4 . As shown in Figure 4 , the porosity of the prepared three-dimensional interconnected multi-level pore structure of zirconia is 87%, and the average density is 0.81 g / cm 3 .

[0077] In this embodiment, the three-dimensional interconnected multi-level pore structure made of zirconia has a compressive strength of 28 MPa. Obviously, compared with the three-dimensional interconnected multi-level pore structure in Example 3, the porosity is increased by 23%, the axial bearing capacity is significantly decreased, and the mechanical compatibility becomes worse, which proves that setting thin plates arranged in a cross pattern inside the column channel 3 has better mechanical properties.

[0078] Example 5

[0079] As another embodiment, according to the preparation process of the high-pressure-bearing three-dimensional connected multi-level pore structure in Embodiment 3, change the wall thickness of the column channels 3 to 0.1 - 0.5 mm respectively, the wall thickness of the crossbeam channels 4 to 0.05 - 0.1 mm respectively, the cross-plate support 31 to a cross plate with a thickness of 0.1 - 0.7 mm respectively, and keep the diameter of the holes 41 symmetrically arranged on the upper, lower, left, and right outer walls of the crossbeam channels 4 unchanged at 1.6 mm, forming 8 structures with a relative density range of 5% - 34%, as described in the following table. The configuration schematic diagram is shown in Figure 5 .

[0080]

[0081] Using titanium alloy material, the ultimate bearing capacities of the 8 structures can be calculated by using finite element software as Figure 6 shown. Its ultimate bearing pressure can reach 40.5 MPa - 295.3 MPa, having a strong bearing capacity, and approximately being proportional to the 1.1 power of the relative density of the structure.

[0082] Furthermore, for the structure in Embodiment 1, cancel the cross-plate support 31 and keep other configurations unchanged, that is, the porous structure in Embodiment 2. Its relative density decreases by 25.6%. Using finite element software to calculate, its ultimate bearing capacity decreases by 34.2% compared with the structure with the cross-plate support 31, that is, the specific strength decreases by 12%, indicating that the cross-plate support 31 can effectively improve the compressive bearing capacity of the structure and improve the material utilization efficiency.

[0083] Embodiment Six

[0084] As another embodiment, according to the preparation process of the high-pressure-bearing three-dimensional connected multi-level pore structure in Embodiment 3, select titanium alloy powder as the raw material. Use the powder bed fusion forming technology to prepare the three-dimensional connected multi-level pore structure with a scanning rate of 600 mm / s and a layer thickness set at 25 μm, and print layer by layer until the final forming. Further, the porosity of the prepared titanium alloy three-dimensional connected multi-level pore structure is 75%, and the average density is 1.81 g / cm 3 .

[0085] In this embodiment, the compressive strength of the three-dimensional connected multi-level pore structure of TC4 material is 590 MPa. Compare it with the Figure 6 curve obtained in Embodiment Five, and it conforms to this change trend.

Claims

1. A high-pressure-bearing three-dimensional connected multi-level pore structure, characterized in that, Comprising: A number of elementary cells, each elementary cell including a vertical enclosing plate (1) and a horizontal enclosing plate (2), with horizontal enclosing plates (2) provided between the upper and lower parts of adjacent two vertical enclosing plates (1), and notches provided on both the upper and lower sides of the middle part of the horizontal enclosing plate (2); the central angle corresponding to each horizontal enclosing plate (2) is 90°; The elementary cells are arrayed in different directions to form a three-dimensional connected multi-level pore structure, the three-dimensional connected multi-level pore structure including a crossbeam channel (4) and a column channel (3), the crossbeam channel (4) and the column channel (3) being hollow inside, four holes (41) being circumferentially opened in the middle of each section of the crossbeam channel (4), the holes (41) being formed by splicing the notches in the middle of the horizontal arc-shaped plates (2); both ends of each section of the crossbeam channel (4) are perpendicularly connected to the side walls of the column channel (3), and the upper and lower ends of the column channel (3) are through; the crossbeam channel (4) and the column channel (3) enclose to form a cavity on a plane, and several cavities in the three-dimensional connected multi-level pore structure communicate with each other; The crossbeam channel (4), the column channel (3), the circumferential holes (41) in the middle of the crossbeam channel (4) and the cavities constitute a multi-level pore structure.

2. The high-pressure-bearing three-dimensional connected multi-level pore structure according to claim 1, wherein: Each elementary cell includes four vertical enclosing plates (1), and the horizontal enclosing plates (2) in each elementary cell enclose to form a square, a rectangle or a hexagon on a horizontal plane; when each elementary cell includes four vertical enclosing plates (1), the central angle corresponding to each vertical enclosing plate (1) is 90°.

3. The highly pressure-bearing three-dimensional connected multi-stage pore structure according to claim 2, characterized in that: The cavities are formed by enclosing between the crossbeam channels (4), the cavities being square, rectangular or hexagonal, and the adjacent two column channels (3) and the two crossbeam channels (4) connected thereto enclose to form a circumferential cavity, the circumferential cavity being square or rectangular.

4. The high-pressure-bearing three-dimensional connected multi-level pore structure according to claim 2, characterized in that: Four vertical enclosing plates (1) are provided in each elementary cell, and a support plate (11) is provided on the vertical enclosing plate (1), with the two end faces of the support plate (11) respectively connected to the two end faces of the vertical enclosing plate (1); the support plate (11) is a flat plate or a curved plate, and a cross-plate support (31) is provided throughout the length in the column channel (3) of the three-dimensional connected multi-level pore structure formed by the array of the elementary cells.

5. The high-pressure-bearing three-dimensional connected multi-level pore structure according to claim 1, wherein: The side length of a single elementary cell is less than 10 mm, and the thickness of the vertical enclosing plate (1) and the horizontal enclosing plate (2) in the elementary cell is 0.1 - 0.75 mm; the diameter of each level of pores in the multi-level pore structure is greater than or equal to 18 μm.

6. The high-pressure-bearing three-dimensional connected multi-level pore structure according to claim 1, wherein: By replacing the vertical enclosing plate (1) and the horizontal enclosing plate (2) with a flat plate with a pore structure, the three-dimensional connected multi-level pore structure formed by splicing the elementary cells is composed of a vertical flat plate and a horizontal flat plate.

7. The preparation method of the high-pressure-bearing three-dimensional connected multi-level pore structure according to any one of claims 1 to 6, characterized in that, Including the following steps: Step 1, editing and designing the elementary cell through modeling software; Step 2, arraying the elementary cell obtained in Step 1 in the modeling software as needed to expand it into a three-dimensional connected multi-level pore structure; Step 3, performing slicing processing on the established three-dimensional model and setting the printing track; Step 4, manufacturing the three-dimensional connected multi-level pore structure layer by layer through a material jetting or powder bed fusion 3D printing system until the final formed blank is printed.

8. The preparation method of the high-pressure-bearing three-dimensional connected multi-level pore structure according to claim 7, characterized in that, In Step 2: As needed, after forming a three-dimensionally connected hierarchical pore structure with the primitive cell arrays, the outermost layer of the three-dimensionally connected hierarchical pore structure is completed so that all the vertical baffles (1) and the horizontal baffles (2) are spliced into complete crossbeam channels (4) and column channels (3).

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