A face-centered cubic based vertical-horizontal mixed enhanced selective laser melting dot structure and a preparation method thereof

Abstract

The application discloses a face-centered cubic (FCC) based vertical-horizontal mixed enhanced selective laser melting dot array structure and a preparation method thereof. The method starts from a basic FCC dot array unit, first forms a transition dot array structure FCC-H (FCC- Horizontal) with in-plane enhancement through the intersection of inclined main rods and auxiliary rods perpendicular to the main rods, further constructs a continuous bridging grid by optimizing the connection mode and diameter ratio of the rods, and finally obtains the FCC-VH (FCC-Vertical Horizontal) dot array structure with vertical-horizontal mixed enhancement. Through the synergistic effect of the inclined main rods and the auxiliary rods perpendicular to the main rods, the structure significantly improves the compressive strength, specific stiffness, specific strength and specific energy absorption while maintaining lightweight. In the experiment, 316L stainless steel powder is used to prepare the FCC-VH dot array structure through selective laser melting technology (SLM), and the compression deformation mode of the FCC-VH dot array structure is changed from local buckling of the basic FCC to multi-node cooperative bearing, so that the overall compression performance is more significantly improved.

Description

Technical Field

[0001] This invention relates to the field of lattice structure optimization design, specifically to a vertical-horizontal hybrid enhanced selective laser melting lattice structure based on face-centered cubic (FCC) and its preparation method. Background Technology

[0002] Face-centered cubic (FCC) lattice structures, as a typical lightweight porous structure, have shown broad application prospects in aerospace, biomedical, and automotive industries due to their excellent specific strength, energy absorption characteristics, and designability. A basic FCC lattice consists of four sets of spatially diagonally intersecting main members, forming periodically arranged cubic units in three-dimensional space, exhibiting high structural symmetry and uniform mechanical properties. However, when subjected to compressive or shear loads, basic FCC structures often experience buckling failure due to localized stress concentration, limiting their load-bearing efficiency and energy absorption capacity.

[0003] The rapid development of additive manufacturing technology has provided new possibilities for the precise fabrication of complex lattice structures, with hybrid reinforcement designs for (face-centered cubic) lattice structures showing significant advantages. By introducing vertical or horizontal reinforcing members into the basic FCC structure, this optimized design can effectively disperse stress concentration and suppress local buckling, thereby significantly improving the mechanical properties of the structure. Specifically, the hybrid reinforcement design increases the number of nodes by adjusting the diameter ratio and spatial distribution of the main and auxiliary members, thus dispersing stress concentration and improving its specific strength, specific stiffness, and specific energy absorption. This structural optimization causes the material to exhibit multi-node, layer-by-layer collapse deformation characteristics under quasi-static compression conditions, making the energy absorption efficiency of the hybrid reinforcement structure far exceed that of the base homogeneous structure. This makes FCC lattice structures promising for applications in lightweight load-bearing components for aerospace and automotive collision energy absorption devices. With the continuous improvement of additive manufacturing process precision, further optimization of the spatial arrangement of members and node connection methods is expected to enable large-scale applications of this type of hybrid reinforcement lattice structure in more engineering fields such as impact protection and vibration absorption.

[0004] Selective Laser Melting (SLM) is a typical metal additive manufacturing technology. Through layer-by-layer cyclic powder deposition, scanning melting, and interlayer remelting, metal powder undergoes a rapid melting-solidification process, achieving precise bottom-up accumulation of a three-dimensional lattice structure. This process offers advantages such as high forming accuracy and short manufacturing cycle, making it particularly suitable for near-net-shape manufacturing of small and medium-sized precision parts. Therefore, it has been widely used in the fabrication of metal lattice structures and is applicable to the manufacturing of the hybrid reinforced lattice structure in this invention. Summary of the Invention

[0005] To address the issue that basic FCC structures often experience buckling failure due to localized stress concentration when subjected to compressive or shear loads, thus limiting their load-bearing efficiency and energy absorption capacity, this invention proposes a vertical-horizontal hybrid enhanced selective laser melting lattice structure based on face-centered cubic (FCC).

[0006] This invention provides a face-centered cubic (FCC) vertical-horizontal hybrid enhanced selective laser melting (SLM) lattice structure, comprising FCC lattice units; each FCC lattice unit is a tetrahedron formed by connecting the ends of two cylindrical main rods in pairs, each face of the tetrahedron consisting of two intersecting cylindrical main rods, with the intersection point located at the center point of the cylindrical main rods; obliquely intersecting auxiliary rods perpendicular to the main rods are introduced horizontally within the FCC lattice unit to form an FCC-H lattice unit with in-plane horizontal enhancement; based on the FCC-H lattice unit, obliquely intersecting auxiliary rods perpendicular to the main rods are introduced vertically to reconstruct the in-plane horizontal enhancement structure into a vertical-horizontal hybrid enhanced FCC-VH lattice unit; the FCC-VH lattice units are stacked along the X, Y, and Z axes to form a face-centered cubic vertical-horizontal hybrid enhanced FCC-VH lattice structure; within the same layer of the FCC-VH lattice structure, adjacent FCC-VH lattice units share cylindrical rods, and the top surfaces of the same layer are flush.

[0007] Furthermore, the horizontal and vertical diagonal cross auxiliary rods are symmetrical about the intersection point of the main rod; the perpendicular points of the auxiliary rods to the main rods are located at 1 / 4 and 3 / 4 of the main rod; the apexes of the diagonal cross auxiliary rods of adjacent main rods are spliced ​​together.

[0008] Furthermore, the diameter of the main rod is 0.2~1.6mm; the diameter ratio of the main rod to the auxiliary rod is 1:0.15~0.9; the height of the vertical-horizontal hybrid reinforced FCC-VH lattice unit is 2~4mm; and the diameter of the main rod is less than or equal to 2 / 5 of the height of the lattice unit.

[0009] Furthermore, the relative density of the face-centered cubic vertical-horizontal hybrid reinforced lattice structure is 7.5%~50%.

[0010] Furthermore, at the same relative density, the vertical-horizontal hybrid reinforced lattice structure based on face-centered cubic (FCC) has a 41%~65% increase in specific strength, a 42%~85% increase in specific stiffness, and a 120%~170% increase in specific energy absorption compared to the FCC lattice structure.

[0011] This invention provides a method for preparing a face-centered cubic vertical-horizontal hybrid reinforced lattice structure. The method uses metal powder with a particle size of 15~53 μm as raw material and prepares the face-centered cubic vertical-horizontal hybrid reinforced lattice structure by selective laser melting technology.

[0012] Further, the method comprises:

[0013] Step 1: designing a vertical-horizontal hybrid reinforced lattice structure by using three-dimensional design software, performing x×x×x array arrangement on a vertical-horizontal hybrid reinforced FCC-VH lattice unit with a main rod diameter of a mm, an auxiliary rod diameter of b mm, and a length×width×height of v mm×v mm×v mm along X, Y and Z axis directions, and constructing a structure with a size of and a relative density of m% (7.5<m<50) vertical-horizontal hybrid reinforced lattice structure;

[0014] Step 2: performing slicing and layering treatment on the vertical-horizontal hybrid reinforced lattice structure model, importing the layered data into laser scanning path software to generate a printing file; importing the printing file into selective laser melting equipment, and setting laser printing parameters;

[0015] Step 3: flatly laying pretreated metal powder on a corresponding metal substrate through a powder feeding device;

[0016] Step 4: performing preparation according to the slicing path and preset parameters under the protection of protective gas until printing is completed to the required height; after all printing is completed and cooled, the formed vertical-horizontal hybrid reinforced lattice structure is obtained.

[0017] Further, the Boolean operation comprises a Boolean union operation and a Boolean difference set operation, wherein the Boolean union operation merges each unit, and the Boolean difference set operation removes redundant materials at corners and edges.

[0018] Further, 316L stainless steel powder is selected as the metal powder; the 316L stainless steel powder is pretreated by drying, the drying temperature is 100~120°C, and the drying time is 4~6h.

[0019] Further, the laser power P L is set to 140~240 W; the scanning speed v is set to 500~1500mm / s.

[0020] The beneficial effects of the present invention are:

[0021] (1) This invention provides a design method for a vertical-horizontal hybrid reinforced lattice structure based on face-centered cubic (FCC). Using a basic FCC lattice structure as the base configuration, and by breaking through the constraints of the in-plane connection method of FCC lattice units, while maintaining the unit size, an auxiliary support structure of vertical main rods is first introduced to form an FCC-H transition configuration. Further optimization of the rod connection method is achieved by improving the auxiliary rods into a network connection, ultimately obtaining an FCC-VH lattice structure. This design significantly enhances the load-bearing capacity of the structure through the synergistic effect of the main rods and auxiliary rods. The hybrid reinforcement design transforms the deformation mode of the structure from local buckling to multi-node collaborative load-bearing. The vertical auxiliary rod network effectively disperses stress concentration, significantly improving the yield strength of the structure. Simultaneously, the introduction of horizontal auxiliary rods strengthens the axial load-bearing capacity of the main rods, making them less prone to bending deformation. By optimizing the structure of the main rods and auxiliary rods, the optimal balance between structural stiffness and energy absorption efficiency is achieved while ensuring the feasibility of additive manufacturing processes.

[0022] (2) This invention provides a design method for a vertical-horizontal hybrid reinforced lattice structure based on face-centered cubic (FCC). The lattice structure is formed using selective laser melting (SLM) technology. Its layer-by-layer accumulation and selective melting processing characteristics provide greater design freedom and process flexibility for the manufacturing of lattice structures. Compared to traditional processing methods, SLM technology can more efficiently form complex structures while significantly reducing production costs and manufacturing cycles, providing an economically feasible solution for the engineering application of lattice structures.

[0023] (3) The hybrid lattice structure design method provided by the present invention can be used, but is not limited to, selective laser melting technology using 316L stainless steel powder as raw material. The design concept can be extended to the performance improvement scheme of FCC lattice structure of other materials or preparation technologies. Attached Figure Description

[0024] Figure 1 A schematic diagram of the hybrid lattice unit design is shown below; (a) is a two-dimensional diagram of the FCC lattice structure with a rod diameter of 0.42 mm and dimensions of 2 mm × 2 mm × 2 mm, and (a1) is the FCC lattice structure after Boolean operation; (b) is a two-dimensional stacked diagram of the FCC-H lattice unit with a main rod diameter of 0.40 mm, an auxiliary rod diameter of 0.20 mm, and dimensions of 2 mm × 2 mm × 2 mm, and (b1) is the lattice unit after Boolean operation; (c) is a two-dimensional diagram of the FCC-VH hybrid reinforced lattice unit with a main rod diameter of 0.38 mm, an auxiliary rod diameter of 0.19 mm, and dimensions of 2 mm × 2 mm × 2 mm, and (c1) is the hybrid reinforced lattice unit after Boolean operation;

[0025] Figure 2The diagram shows a lattice structure model with dimensions of 10 mm × 10 mm × 10 mm and a relative density of 16%; where (a) is the FCC lattice structure; (b) is the FCC-H lattice structure; and (c) is the FCC-VH lattice structure.

[0026] Figure 3 The images show physical diagrams and cross-sectional views of a lattice structure with dimensions of 10 mm × 10 mm × 10 mm and a relative density of 16%; where: (a) FCC lattice structure; (b) FCC-H lattice structure; (c) FCC-VH lattice structure; (a1) Cross-section of FCC lattice structure; (b1) Cross-section of FCC-H lattice structure; (c1) Cross-section of FCC-VH lattice structure;

[0027] Figure 4 Performance test diagrams for FCC, FCC-H and FCC-VH lattice structures are shown; where (a) is the quasi-static compressive stress-strain curve, (b) is the specific stiffness, (c) is the specific strength, and (d) is the specific energy absorption. Detailed Implementation

[0028] To make the technical solution and implementation of the present invention clearer, the present invention will be further described below with reference to the accompanying drawings.

[0029] This invention discloses a design method for a vertical-horizontal hybrid reinforced selective laser melting lattice structure based on face-centered cubic (FCC). Since the compressive strength of FCC lattice units is closely related to the connection method and diameter ratio of the members, this method first introduces obliquely intersecting auxiliary rods perpendicular to the main rods within the FCC lattice structure, forming an FCC-H (FCC-Horizontal) lattice structure with in-plane horizontal reinforcement. Through the synergistic effect of the inclined main rods and the auxiliary rods perpendicular to the main rods, this structure further improves the load-bearing and energy absorption performance of the structure while maintaining lightweight design. Simultaneously, this lattice structure serves as a transitional lattice structure in the lattice design. Further optimization of the member connection method is achieved within this FCC-H lattice structure, and another set of obliquely intersecting auxiliary rods perpendicular to the main rods is introduced, reconstructing the in-plane horizontal reinforcement structure into a vertical-horizontal hybrid reinforced FCC-VH (FCC-Vertical Horizontal) lattice structure. Using 316L stainless steel powder as raw material, basic FCC lattice structures, FCC-H lattice structures, and FCC-VH lattice structures were fabricated using selective laser melting (SLM) technology. By adding auxiliary rods perpendicular to the main rods to the FCC lattice structures and optimizing the rod connection method and diameter, the compression deformation mode of the FCC-VH was transformed from the local buckling of the FCC to multi-node collaborative load-bearing. The vertical-horizontal auxiliary rod mesh effectively dispersed stress concentration, increasing the overall structure's yield strength during compression. Furthermore, the optimized diameters of the main rods and auxiliary rods maximized the structure's specific strength, specific stiffness, and specific energy absorption while ensuring printability.

[0030] The vertical-horizontal hybrid enhancement selective laser melting lattice structure based on face-centered cubic (FCC) includes face-centered cubic lattice units, each with multiple vertices. Each face of the face-centered cubic lattice unit is a tetrahedron formed by connecting the endpoints of main rods in pairs, with hollow top and bottom surfaces. Each face of the tetrahedron consists of two intersecting main rods, with the intersection point located at the center of the cylindrical rod. Horizontally, obliquely intersecting auxiliary rods perpendicular to the main rods are introduced into the face-centered cubic lattice unit, forming an FCC-H lattice unit with in-plane horizontal enhancement. Based on the FCC-H lattice unit, obliquely intersecting auxiliary rods perpendicular to the main rods are introduced vertically, reconstructing the in-plane horizontal enhancement structure into a vertical-horizontal hybrid enhancement FCC-VH lattice unit. CC-VH lattice units are stacked along the X, Y, and Z axes to form a vertical-horizontal hybrid reinforced FCC-VH lattice structure based on face-centered cubic. Since the cylindrical rods of adjacent FCC-VH lattice units overlap during stacking, Boolean union operations are used to merge the units, and Boolean difference operations are used to remove redundant material at the edges. The resulting FCC-VH lattice structure has FCC-VH lattice units composed of semi-cylinders, each a cylindrical rod cut vertically from the middle. The outer surface of each FCC-VH lattice unit is planar, while the inner surface is curved. Within the same layer of the FCC-VH lattice structure, adjacent FCC-VH lattice units share the same cylindrical rod, and the top surfaces of the FCC-VH lattice units in the same layer are flush.

[0031] The main rod diameter is 0.2~1.6mm; the ratio of the main rod to the auxiliary rod diameter is 1:0.15~0.9; the height of the vertical-horizontal hybrid reinforced FCC-VH lattice unit is 2~4mm; the main rod diameter is less than or equal to 2 / 5 of the lattice unit height. The relative density of the face-centered cubic vertical-horizontal hybrid reinforced lattice structure is 7.5%~50%.

[0032] At the same relative density, compared with the FCC lattice structure, FCC-VH has a 41%~65% increase in specific strength, a 42%~85% increase in specific stiffness, and a 120%~170% increase in specific energy absorption.

[0033] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0034] The method for designing a vertical-horizontal hybrid reinforced selective laser melting (SLM) lattice structure based on face-centered cubic (FCC) involves changing the rod diameter of the FCC lattice structure, adding auxiliary rods to form a transitional FCC-H structure and an FCC-VH structure with vertical-horizontal hybrid reinforcement. The method then employs SLM to fabricate 316L stainless steel FCC, FCC-H, and FCC-VH structures layer by layer until the lattice sample is formed. The specific steps are as follows:

[0035] S1. A vertical-horizontal hybrid reinforced FCC-VH lattice structure is designed using 3D design software. Based on a basic FCC lattice unit (composed of four sets of spatial cross rods) with a main rod diameter of b1mm and length × width × height of v mm × v mm × v mm, the cross rods in each plane are reinforced. At the 1 / 4 and 3 / 4 positions of each main rod (along the horizontal direction of the main rod), four auxiliary rods extend vertically into the plane containing the two cross rods. The length of the auxiliary rods is 1 / 4 of the length of the main rod, the diameter is d1 mm, and they are symmetrically distributed on the left and right sides of the main rod intersection point, forming a v mm × v mm × v mm horizontal reinforced FCC-H lattice unit. Based on this, at the 1 / 4 and 3 / 4 positions of each main rod (along the length direction of the main rod), four auxiliary rods extend vertically into the plane containing the two cross rods. The length of the auxiliary rods is 1 / 4 of the length of the main rod, the diameter is d1 mm, and they are symmetrically distributed on the upper and lower sides of the main rod intersection point. A hybrid vertical-horizontal enhanced FCC-VH lattice element with dimensions v mm × v mm × v mm is formed, and then arranged in an x ​​× x × x array along the X, Y, and Z axes. Combined with Boolean operations, a structure with dimensions of [missing information] is constructed. FCC-VH lattice structure with a relative density of n%;

[0036] S2. The proposed FCC-VH series lattice structure is made using 316L stainless steel powder as the raw material and selective laser melting as the forming technology.

[0037] S3. Slice the 3D raster model and set appropriate process parameters;

[0038] S4. Prepare the sample according to the slicing path and predetermined parameters until the sample preparation is complete.

[0039] The present invention also includes the following features:

[0040] The Boolean operation described in S1 is as follows: Boolean union operation merges each unit, and Boolean difference operation removes redundant material from the corners; after the Boolean difference operation, the main rod and auxiliary rod of the lattice unit in the FCC-VH lattice structure are semi-cylindrical rods, which are obtained by cutting a cylindrical rod from the middle in the vertical direction. The outer surface of the FCC-VH lattice unit is a cutting plane, and the inner surface is a curved surface.

[0041] Before the 316L stainless steel powder mentioned in S1 is loaded into the powder feeder of the equipment, it needs to be dried. The drying temperature is 100~120 ℃ and the drying time is 3~4 h.

[0042] The process parameters mentioned in S3 include: laser power P L And scanning speed v; laser power P LSet to 140~240 W; set the scanning speed v to 500~1500 mm / s.

[0043] Example 1

[0044] Using 316L stainless steel powder as raw material, an FCC-VH lattice structure was prepared by selective laser melting. The FCC-VH lattice structure consists of periodically arranged 2 mm × 2 mm × 2 mm units, with overall dimensions of 10 mm × 10 mm × 10 mm and a relative density of 16%. Based on the basic FCC lattice structure, by overcoming the constraints of the in-plane connection method of the FCC lattice units, and while maintaining the unit size, an auxiliary support structure with vertical main rods was first introduced to form an FCC-H transition configuration. Further optimization of the rod connection method was achieved by improving the auxiliary rods to a grid-like connection, ultimately obtaining the FCC-VH lattice structure. This design significantly enhances the load-bearing capacity of the structure through the synergistic effect of the main rods and auxiliary rods.

[0045] S1. A vertical-horizontal hybrid reinforced FCC-VH lattice structure is designed using 3D design software; the main rod diameter is 0.38 mm, the auxiliary rod diameter is 0.19 mm, and the length × width × height is 2 mm × 2 mm × 2 mm. Eight auxiliary rods extend vertically into the plane containing the two intersecting main rods at 1 / 4 and 3 / 4 positions of each main rod (along the length direction and along the horizontal direction of the main rod). The length of each auxiliary rod is 1 / 4 of the main rod length, and the diameter is 0.19 mm. mm, and symmetrically distributed on the upper, lower, left and right sides of the main rod intersection. A 2 mm × 2 mm × 2 mm hybrid vertical-horizontal reinforced FCC-VH lattice unit is formed, and then it is arranged in a 5 × 5 × 5 array along the X, Y and Z axes. Combined with Boolean operations, an FCC-VH lattice structure with a size of 10 mm × 10 mm × 10 mm and a relative density of 16% is constructed.

[0046] S2. The FCC-VH lattice structure to be prepared uses 316L stainless steel powder as raw material and selective laser melting as forming technology.

[0047] S3. Slice the 3D raster model and set appropriate process parameters;

[0048] S4. Prepare the sample according to the slicing path and predetermined parameters until the sample preparation is complete.

[0049] The Boolean operations described in S1 are: Boolean union operation to merge all units, and Boolean difference operation to remove redundant materials at the edges and corners;

[0050] The 316L stainless steel powder described in S3 needs to be dried at a temperature of 100 ℃ for 4 hours before being loaded into the powder feeder of the equipment in order to improve the powder flowability and ensure the continuity and stability of the powder during the conveying process.

[0051] Comparative Example 1

[0052] FCC lattice structures were prepared using 316L stainless steel powder as raw material and selective laser melting.

[0053] S1. A vertical-horizontal hybrid reinforced FCC dot matrix structure is designed using 3D design software. The basic FCC dot matrix unit (composed of four sets of spatially intersecting main rods) with a rod diameter of 0.42 mm and a length × width × height of 2 mm × 2 mm × 2 mm is arranged in a 5×5×5 array along the X, Y and Z axes (where x is a positive integer). Combined with Boolean operations, an FCC dot matrix structure with a size of 10 mm × 10 mm × 10 mm and a relative density of 16% is constructed.

[0054] S2. The FCC lattice structure to be prepared uses 316L stainless steel powder as raw material and selective laser melting as forming technology.

[0055] S3. Slice the 3D raster model and set appropriate process parameters;

[0056] S4. Prepare the sample according to the slicing path and predetermined parameters until the sample preparation is complete.

[0057] The Boolean operations described in S1 are: Boolean union operation to merge all units, and Boolean difference operation to remove redundant materials at the edges and corners;

[0058] The 316L stainless steel powder described in S3 needs to be dried at a temperature of 100 ℃ for 4 hours before being loaded into the powder feeder of the equipment in order to improve the powder flowability and ensure the continuity and stability of the powder during the conveying process.

[0059] Comparative Example 2

[0060] FCC-H lattice structures were prepared using 316L stainless steel powder as raw material and selective laser melting was used.

[0061] S1. A vertical-horizontal hybrid reinforced FCC-H lattice structure is designed using 3D design software. The main rod diameter is 0.40 mm, the auxiliary rod diameter is 0.20 mm, and the length × width × height is 2 mm × 2 mm × 2 mm. At the 1 / 4 and 3 / 4 positions of each main rod (along the horizontal direction of the main rod), four auxiliary rods extend vertically into the plane where the two intersecting main rods are located. The length of the auxiliary rods is 1 / 4 of the length of the main rod, the diameter is 0.20 mm, and they are symmetrically distributed on the left and right sides of the intersection of the main rods, forming 2 mm × 2 mm × 2 mm horizontal reinforced FCC-H lattice units. Then, they are arranged in a 5 × 5 × 5 array along the X, Y, and Z axes. Combined with Boolean operations, an FCC-H lattice structure with a size of 10 mm × 10 mm × 10 mm and a relative density of 16% is constructed.

[0062] Depend on Figure 3 As can be seen, the FCC, FCC-H, and FCC-VH lattice structures are fully formed. The overall macroscopic morphology of the structure is consistent with the design model, and the geometric features such as the rod structure and rod diameter variation all meet the design requirements.

[0063] Depend on Figure 4 As can be seen, compared with the FCC lattice structure, the FCC-H lattice structure improves specific stiffness, specific strength, and specific energy absorption performance by 33.87%, 42.07%, and 96.45%, respectively. Furthermore, the FCC-VH lattice structure with a mixed rod diameter design shows even more significant improvements in specific stiffness, specific strength, and specific energy absorption performance, with increases of 56.35%, 72.44%, and 154.81%, respectively.

[0064] As can be seen, the present invention has optimized the design of the uniform FCC lattice structure. By adjusting the rod diameter and adding auxiliary rod diameter, the specific stiffness, specific strength and specific energy absorption performance of the lattice structure are significantly improved.

[0065] This invention provides a vertical-horizontal hybrid reinforcement lattice structure design method based on face-centered cubic (FCC). The FCC-VH lattice structure is formed using selective laser melting (SLM) technology. Compared to traditional processing methods, this method achieves more efficient and precise forming of complex rod meshes while maintaining excellent lightweight characteristics. The FCC-H lattice structure employs a vertical auxiliary rod design, significantly improving the in-plane load-bearing capacity. Further optimized, the hybrid reinforcement FCC-VH lattice structure introduces horizontally bridging auxiliary rod meshes, achieving synergistic load-bearing between the main rods and auxiliary rods, thereby further enhancing the overall stiffness and energy absorption performance of the structure. This hybrid reinforcement design method achieves a synergistic improvement in load-bearing capacity and energy absorption performance. The vertical-horizontal hybrid reinforcement design method provided by this invention can be applied to, but is not limited to, selective laser melting technology using 316L stainless steel powder as raw material. Its design concept can be extended to performance optimization schemes for lightweight lattice structures using other metal materials or additive manufacturing processes.

[0066] Finally, it should be noted that the above embodiments are for illustration only and not for limiting the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A face-centered cubic vertical-horizontal hybrid enhanced selective laser melting lattice structure, characterized in that, The system includes face-centered cubic lattice elements; each face-centered cubic lattice element is a tetrahedron formed by connecting the endpoints of two cylindrical main rods in pairs. Each face of the tetrahedron consists of two intersecting main rods, with the intersection point located at the center of the main rod. Horizontally, obliquely intersecting auxiliary rods perpendicular to the main rods are introduced into the face-centered cubic lattice elements to form an FCC-H lattice element with in-plane horizontal reinforcement. Based on the FCC-H lattice element, obliquely intersecting auxiliary rods perpendicular to the main rods are introduced vertically, reconstructing the in-plane horizontal reinforcement structure into a vertical-horizontal hybrid reinforcement FCC-V. H-type lattice units; the FCC-VH lattice units are stacked along X, Y, and Z to form a face-centered cubic vertical-horizontal hybrid reinforced FCC-VH lattice structure; within the same layer of the FCC-VH lattice structure, adjacent FCC-VH lattice units share a cylindrical main rod, and the top surfaces of the same layer are flush; the obliquely intersecting auxiliary rods in the horizontal and vertical directions are symmetrical about the intersection point of the main rod; the perpendicular points of the auxiliary rods to the main rods are located at 1 / 4 and 3 / 4 of the main rod; the vertices of the obliquely intersecting auxiliary rods of adjacent main rods are spliced ​​together.

2. The face-centered cubic vertical-horizontal hybrid enhanced selective laser melting lattice structure according to claim 1, characterized in that, The diameter of the main rod is 0.2~1.6mm; the diameter ratio of the main rod to the auxiliary rod is 1:0.15~0.9; the height of the vertical-horizontal hybrid reinforced FCC-VH lattice unit is 2~4mm; the diameter of the main rod is less than or equal to 2 / 5 of the height of the lattice unit.

3. The face-centered cubic vertical-horizontal hybrid enhanced selective laser melting lattice structure according to claim 1, characterized in that, The relative density of the face-centered cubic vertical-horizontal hybrid reinforced lattice structure is 7.5%~50%.

4. The face-centered cubic vertical-horizontal hybrid enhanced selective laser melting lattice structure according to claim 1, characterized in that, At the same relative density, the vertical-horizontal hybrid reinforced lattice structure based on face-centered cubic has a 41%~65% increase in specific strength, a 42%~85% increase in specific stiffness, and a 120%~170% increase in specific energy absorption compared with the face-centered cubic lattice structure.

5. A method for fabricating a face-centered cubic vertical-horizontal hybrid enhanced selective laser melting lattice structure as described in any one of claims 1 to 4, characterized in that, Using metal powder with a particle size of 15~53 μm as raw material, a face-centered cubic vertical-horizontal hybrid reinforced lattice structure was prepared by selective laser melting technology.

6. The method for fabricating a face-centered cubic vertical-horizontal hybrid enhanced selective laser melting lattice structure according to claim 5, characterized in that, include: Step 1: Design a vertical-horizontal hybrid enhanced lattice structure using three-dimensional design software, array the vertical-horizontal hybrid enhanced FCC-VH lattice unit with a main rod diameter of a mm, an auxiliary rod diameter of b mm, and a length×width×height of v mm×v mm×v mm in an x×x×x array along the X, Y and Z axes, and combine with Boolean operation to construct a structure with a size of vertical-horizontal hybrid enhanced lattice structure with a relative density of m% (7.5<m<50); Step 2: Slice and layer the vertical-horizontal hybrid enhanced lattice structure model, import the layered data into the laser scanning path software, and generate a print file; Import the print file into the selection area laser melting equipment and set the laser printing parameters; Step 3: The pretreated metal powder is spread evenly on the corresponding metal substrate using a powder feeding device; Step 4: Under the protection of a protective gas, prepare the slicing according to the slicing path and predetermined parameters until the desired height is reached; After all printing is completed and the material has cooled, a vertical-horizontal hybrid reinforced lattice structure is obtained.

7. The method for fabricating a face-centered cubic vertical-horizontal hybrid enhanced selective laser melting lattice structure according to claim 6, characterized in that, The Boolean operations include Boolean union and Boolean difference. Boolean union merges the units, and Boolean difference removes redundant material from the edges and corners.

8. The method for fabricating a face-centered cubic vertical-horizontal hybrid enhanced selective laser melting lattice structure according to claim 6, characterized in that, The metal powder is selected from 316L stainless steel powder; the 316L stainless steel powder is pretreated by drying, with a drying temperature of 100~120℃ and a drying time of 4~6h.

9. The method for fabricating a face-centered cubic vertical-horizontal hybrid enhanced selective laser melting lattice structure according to claim 6, characterized in that, The laser power P L The setting is 140~240 W; the scanning speed v is set to 500~1500 mm / s.

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