Bionic structure titanium alloy frame reinforced magnesium-based composite material and preparation method and application thereof

Abstract

This invention discloses a biomimetic structural titanium alloy frame reinforced magnesium matrix composite material, its preparation method, and its application, belonging to the technical field of magnesium alloy composite materials. The biomimetic structural titanium alloy frame reinforced magnesium matrix composite material comprises a magnesium alloy matrix and a multi-layered mesh-like titanium alloy frame, with the multi-layered mesh-like titanium alloy frame stacked within the magnesium alloy matrix. The volume of all solid titanium alloy frame portions accounts for 5% to 50% of the total volume of the biomimetic structural titanium alloy frame reinforced magnesium matrix composite material. The thickness of a single titanium alloy frame layer is 1 mm to 3 mm, the mesh volume percentage is 10% to 80%, and the size of a single mesh opening in the titanium alloy frame is 0.1 mm to 0.5 mm. This magnesium matrix composite material exhibits high density, uniform composition, and excellent comprehensive mechanical properties, making it suitable for manufacturing structural components such as mobile phone casings.

Description

Technical Field

[0001] This invention relates to the field of magnesium alloy composite materials technology, and more specifically, to a biomimetic structure titanium alloy frame reinforced magnesium matrix composite material, its preparation method and application. Background Technology

[0002] Magnesium alloys are hailed as highly promising lightweight structural materials due to their low density, but their inherently low strength and modulus limit their widespread application in critical load-bearing components. To overcome this bottleneck, inspired by reinforced concrete structures, a biomimetic reinforcement strategy of introducing a metal framework into the magnesium matrix has become an important direction for improving its comprehensive mechanical properties. However, the current mainstream technology for preparing composite materials using magnesium alloy melt infiltration has significant drawbacks: the high-temperature melt infiltration process easily triggers a violent interfacial reaction between the reinforcement and the matrix, forming brittle compounds that weaken the interfacial bonding strength, and compositional segregation easily occurs within the magnesium matrix; simultaneously, magnesium melt is highly susceptible to oxidation, leading to a decrease in matrix purity, and is prone to defects such as porosity due to solidification shrinkage, making it difficult to achieve complete densification of the microstructure; moreover, magnesium melt is difficult to completely fill the pores within the titanium alloy framework. These factors collectively restrict the full realization of the final mechanical properties of magnesium-based composite materials.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a biomimetic structure titanium alloy frame reinforced magnesium matrix composite material, its preparation method and application, so as to solve or improve the above-mentioned technical problems.

[0005] This invention can be implemented as follows: In a first aspect, the present invention provides a biomimetic structure titanium alloy frame reinforced magnesium matrix composite material, the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material comprising a magnesium alloy matrix and a multi-layered mesh sheet structure titanium alloy frame, the multi-layered mesh sheet structure titanium alloy frame being stacked in the magnesium alloy matrix. The volume of all solid titanium alloy frame components is 5% to 50% of the total volume of the biomimetic titanium alloy frame reinforced magnesium matrix composite material. The thickness of a single-layer titanium alloy frame is 1mm to 3mm, the volume ratio of all meshes in the single-layer titanium alloy frame is 10% to 80%, and the size of a single mesh in the titanium alloy frame is 0.1mm to 0.5mm. Along the vertical direction, the mesh size in the multi-layer titanium alloy frame gradually increases from bottom to top; the mesh size is the same in the same layer of titanium alloy frame.

[0006] In an optional implementation, the mesh shape in the single-layer titanium alloy frame includes circular, rectangular, or hexagonal shapes.

[0007] In an optional embodiment, the biomimetic structural titanium alloy frame reinforced magnesium matrix composite material has at least one of the following characteristics: Feature 1: The density of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material is 1.8 g / cm³. 3 ~3.0g / cm 3 ; Feature 2: The density of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material is ≥99%; Feature 3: The interfacial bonding strength of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material is ≥200MPa; Feature 4: The tensile strength of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material is ≥600MPa; Feature 5: The compressive strength of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material is ≥1000MPa; Feature 6: The elongation of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material is ≥10%.

[0008] In a second aspect, the present invention provides a method for preparing a biomimetic structure titanium alloy frame reinforced magnesium matrix composite material as described in any of the foregoing embodiments, comprising the following steps: spreading a first layer of magnesium alloy powder, placing a first layer of titanium alloy frame on the first layer of magnesium alloy powder, and then continuing to set the first layer of magnesium alloy powder followed by the titanium alloy frame until a preset number of layers is reached; then performing hot pressing sintering and hot isostatic pressing.

[0009] In an optional embodiment, the average particle size of the magnesium alloy powder is 50 μm to 100 μm.

[0010] In an optional embodiment, the thickness of the first layer of magnesium alloy powder is 2mm to 5mm.

[0011] In an optional embodiment, the titanium alloy frame is fabricated by 3D printing, with the following 3D printing conditions: laser power of 100W~300W and scanning speed of 500mm / s~1000mm / s.

[0012] In an optional implementation, 3D printing is performed under a protective atmosphere.

[0013] In an optional embodiment, the hot pressing sintering conditions include: a pressure of 30 MPa to 50 MPa, a temperature of 500°C to 580°C, and a time of 1 to 2 hours.

[0014] In an optional embodiment, the heating rate during hot pressing sintering is 5°C / min to 10°C / min.

[0015] In an optional embodiment, after hot pressing and sintering, the temperature is reduced at a rate of 1°C / min to 5°C / min.

[0016] In an optional implementation, the hot isostatic pressing conditions include: a pressure of 80 MPa to 120 MPa, a temperature of 500°C to 580°C, and a time of 1.5 h to 2 h.

[0017] In an optional implementation, the heating rate during hot isostatic pressing is 5°C / min to 10°C / min.

[0018] In an optional embodiment, after hot isostatic pressing, the temperature is reduced at a rate of 1°C / min to 5°C / min.

[0019] Thirdly, the present invention provides an application of the biomimetic structural titanium alloy frame reinforced magnesium matrix composite material as described in any of the foregoing embodiments, for example, using it to prepare structural components.

[0020] In an alternative implementation, the structural component includes a mobile phone casing.

[0021] The beneficial effects of this invention include: The method for preparing magnesium-based composite materials provided by this invention, which involves alternating layers of mesh-like titanium alloy mesh and magnesium alloy powder, combined with hot pressing sintering and hot isostatic pressing, offers significantly improved overall performance and superior oxidation control compared to traditional frame-based melting infiltration magnesium alloy processes. This method, through layer-by-layer powder laying and stacking molding, ensures that magnesium alloy powder is uniformly filled within the titanium alloy mesh framework. Hot pressing sintering further densifies the structure, and hot isostatic pressing further eliminates porosity, resulting in a substantial reduction in internal defects within the magnesium matrix. Furthermore, because the oxidation environment of magnesium alloy powder is easier to control than molten magnesium during powder metallurgy, the oxidation behavior of the magnesium matrix is ​​significantly reduced, leading to a purer microstructure. Regarding interfacial bonding, the hot pressing and hot isostatic pressing processes promote strong metallurgical bonding between the magnesium alloy and the titanium alloy mesh through diffusion in the solid state. This tight and continuous interfacial bonding effectively avoids problems such as poor bonding, voids, and brittle phase aggregation that may occur in melting infiltration methods due to differences in melt flowability, solidification shrinkage, and interfacial reactions. These structural advantages collectively result in composite materials exhibiting higher tensile strength, compressive strength, and elongation, with comprehensive optimization of mechanical properties. They are particularly suitable for precision structural components such as mobile phone casings, where lightweighting, strength, ductility, and aesthetic integrity are required, and have significant application prospects. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1This is a schematic diagram of the titanium alloy frame in Example 1; Figure 2 This is a schematic diagram of the titanium alloy frame in Example 2; Figure 3 This is a schematic diagram of the titanium alloy frame in Example 3; Figure 4 This is a SEM image of the fracture surface of the biomimetic titanium alloy frame reinforced magnesium matrix composite material in Example 1; Figure 5 This is a high-magnification SEM image of the fracture surface of the biomimetic titanium alloy frame reinforced magnesium matrix composite material in Example 1; Figure 6 This is a graph showing the tensile strength results of the biomimetic titanium alloy frame-reinforced magnesium matrix composite material in Example 1; Figure 7 The graph shows the compressive strength results of the biomimetic titanium alloy frame-reinforced magnesium matrix composite material in Example 1. Figure 8 This is a morphology diagram of the severely oxidized interior of the magnesium matrix prepared by melt infiltration in Comparative Example 1. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0025] The following is a detailed description of the biomimetic structural titanium alloy frame reinforced magnesium matrix composite material, its preparation method, and its application provided by the present invention.

[0026] The biomimetic titanium alloy frame-reinforced magnesium matrix composite material provided by this invention includes a magnesium alloy matrix and a multi-layered, mesh-like titanium alloy frame, which is stacked within the magnesium alloy matrix. Except for the solid regions of the titanium alloy frame, the magnesium alloy matrix is ​​vertically connected.

[0027] The aforementioned titanium alloy frame is beneficial for achieving efficient load transfer and uniform stress distribution, and it can also provide some constraint on the magnesium alloy matrix, suppressing local deformation and crack initiation.

[0028] The volume of all titanium alloy frame solid parts is 5% to 50% of the total volume of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material, such as 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%, or other values ​​within the range of 5% to 50%.

[0029] If the volume percentage of the solid portion of the titanium alloy frame is less than 5%, the strengthening effect of the titanium alloy reinforcing phase is insufficient, which is detrimental to the improvement of the overall mechanical properties of the material (especially strength and stiffness), and the advantages of composite materials cannot be fully utilized. If the volume percentage of the solid portion of the titanium alloy frame is greater than 50%, the density of the material increases significantly, the lightweight advantage is weakened, and the proportion of the magnesium matrix as a continuous phase is too low, which is not conducive to maintaining the toughness and subsequent processing performance of the material, and may lead to a sharp increase in cost. Preferably, the volume of all solid portions of the titanium alloy frame is 15% to 35% of the total volume of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material.

[0030] The thickness of a single-layer titanium alloy frame can be 1mm to 3mm, such as 1mm, 1.5mm, 2mm, 2.5mm or 3mm, or other values ​​within the range of 1mm to 3mm.

[0031] If the thickness of the single-layer titanium alloy frame is too thin, its structural strength and stiffness will be insufficient, making it prone to deformation or damage during powder laying and subsequent pressing. It will not be able to serve as an effective load-bearing skeleton to provide stable reinforcement for the composite material. At the same time, an excessively thin frame will also lead to a relatively reduced interface area between the frame and the magnesium matrix, which is not conducive to stress transfer and improvement of interface bonding strength. If the thickness of the single-layer titanium alloy frame is too thick, it will significantly increase the rigidity of the single-layer structure, which may affect the density and uniformity of multi-layer powder laying and stacking, leading to weakened interlayer bonding. At the same time, an excessively thick solid part will reduce the topology optimization effect of the biomimetic structure, making the material tend to be a bulky laminate structure, weakening its advantages of lightweight and biomimetic design, and may become a source of stress concentration due to abrupt changes in local stiffness.

[0032] The volume percentage of all mesh holes in a single-layer titanium alloy frame can be 10% to 80%, such as 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80%, or other values ​​within the range of 10% to 80%.

[0033] If the mesh size is less than 10%, the solid frame is too dense, leading to a significant increase in structural weight and weakening the lightweight advantage of the composite material. Simultaneously, the dense titanium alloy layer excessively restricts the filling of magnesium alloy powder, hindering the formation of a uniform, interlocking composite interface during subsequent hot pressing. Furthermore, excessive segmentation of the magnesium matrix may affect its continuity, reducing the overall toughness of the material. If the mesh size is greater than 80%, the solid skeleton of the frame is too small and sparse, resulting in a significant decrease in its strength and stiffness as the main load-bearing structure. This makes it unable to effectively bear and transfer loads, leading to a weak strengthening effect of the composite material and potentially a decrease in mechanical properties. Moreover, excessive porosity makes the frame more prone to deformation during powder spreading and pressing, making it difficult to maintain the intended biomimetic structural morphology. Ideally, the volume percentage of all meshes in a single-layer titanium alloy frame is 30% to 65%.

[0034] The size of a single mesh in the titanium alloy frame can be 0.1mm to 0.5mm, such as 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm, or other values ​​within the range of 0.1mm to 0.5mm.

[0035] If the size of a single mesh in the titanium alloy framework is less than 0.1 mm, the mesh is too fine and easily blocked by magnesium alloy powder during the preparation process. This makes it difficult for the magnesium matrix to be completely filled and dense, easily forming unfilled micropore defects. At the same time, the excessively small mesh will greatly increase the interface area between the titanium and magnesium phases, which may induce excessive interfacial reactions, generating brittle intermetallic compounds and impairing the interfacial bonding quality and material toughness. If the size of a single mesh in the titanium alloy framework is greater than 0.5 mm, the mesh is too coarse, which will significantly reduce the continuity and load-bearing efficiency of the titanium alloy skeleton, weaken its effective reinforcement and constraint effect on the magnesium matrix, and lead to increased stress concentration in the composite material under stress, resulting in decreased uniformity and stability of mechanical properties. At the same time, excessively large pores may make the magnesium matrix region too large, reverting to the performance characteristics close to pure magnesium alloy, and failing to fully exert the synergistic strengthening effect of micro-composite.

[0036] In this invention, along the vertical direction, the mesh size of the multi-layer titanium alloy frame gradually increases from bottom to top; the mesh size is the same in the same layer of titanium alloy frame. Preferably, the mesh size increases uniformly. That is, in any three adjacent multi-layer titanium alloy frames, from bottom to top, they are defined as the first titanium alloy frame, the second titanium alloy frame, and the third titanium alloy frame, wherein the mesh size of the first titanium alloy frame is d1, the mesh size of the second titanium alloy frame is d2, and the mesh size of the third titanium alloy frame is d3, and d2-d1=d3-d2. More preferably, the difference in mesh size between two adjacent titanium alloy frames, i.e., the range of the above-mentioned d2-d1 or d3-d2 values, is 0.1mm~0.3mm.

[0037] It is more conducive to controlling the volume fraction and spatial distribution of each layer of reinforcement while ensuring the continuity and smooth transition of the gradient structure, optimizing the interfacial bonding state and mechanical property transfer efficiency between the titanium / magnesium phases, so that the composite material can achieve the best synergy of strength and toughness under the premise of lightweight.

[0038] By setting the mesh size in each layer of the titanium alloy frame to increase uniformly from bottom to top, it is beneficial to construct a continuous mechanical gradient structure within the composite material that matches the natural load-bearing path. This structure can more smoothly transfer and disperse external loads, effectively alleviate stress concentration caused by abrupt changes in material properties, and avoid excessive stress concentration at a single interface or region, thereby improving the overall structural stability and mechanical properties of the composite material. Simultaneously, the bottom-to-top mesh size increase arrangement helps the powder effectively fill the pores within the frame under gravity, reducing internal defects and obtaining a denser, more uniform composite structure. It also helps promote the effective filling of the pores within the frame by magnesium alloy powder under gravity during hot-pressing sintering, reducing uneven filling or interface defects caused by abrupt changes in mesh size, reducing internal defects, obtaining a denser, more uniform composite structure, and ensuring the quality of interlayer bonding. Furthermore, controlling the difference in mesh size between two adjacent titanium alloy frames within the range of 0.1mm to 0.3mm is more conducive to controlling the volume fraction and spatial distribution of each layer of reinforcement while ensuring the continuity and smooth transition of the gradient structure. This avoids the formation of local weak interfaces or stress distortion zones due to excessive changes in mesh size between adjacent layers, optimizes the interfacial bonding state and mechanical property transfer efficiency between the titanium and magnesium phases, and enables the composite material to achieve the best synergy of strength and toughness under the premise of lightweighting.

[0039] In some alternative embodiments, the shape of the mesh openings in the single-layer titanium alloy frame may, by way of example but not limitation, include circular, rectangular, or hexagonal shapes. When the mesh opening shape is circular, the size of a single mesh opening refers to the diameter of the circular mesh opening; when the mesh opening shape is rectangular or hexagonal, the size of a single mesh opening refers to the side length of the rectangular or hexagonal mesh opening.

[0040] In some alternative embodiments, the density of the biomimetic structural titanium alloy frame reinforced magnesium matrix composite is 1.8 g / cm³. 3 ~3.0g / cm 3 .

[0041] In some alternative implementations, the density of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material is ≥99%, such as 99.1%~99.8%.

[0042] In some alternative implementations, the interfacial bonding strength of the biomimetic titanium alloy frame reinforced magnesium matrix composite material is ≥200MPa, such as 200MPa~263MPa.

[0043] In some alternative implementations, the tensile strength of the biomimetic titanium alloy frame reinforced magnesium matrix composite material is ≥600MPa, such as 600MPa~632MPa.

[0044] In some alternative embodiments, the compressive strength of the biomimetic titanium alloy frame reinforced magnesium matrix composite material is ≥1000MPa, such as 1000MPa~1158MPa.

[0045] In some alternative implementations, the elongation of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite is ≥10%, such as 10%~18%.

[0046] As mentioned above, the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material provided by this invention has high microstructure density, uniform composition, and excellent comprehensive mechanical properties.

[0047] Accordingly, the present invention also provides a method for preparing the above-mentioned biomimetic structure titanium alloy frame reinforced magnesium matrix composite material, comprising the following steps: spreading a first layer of magnesium alloy powder, placing a first layer of titanium alloy frame on the first layer of magnesium alloy powder, and then continuing to set the first layer of magnesium alloy powder followed by the titanium alloy frame until a preset number of layers is reached; then performing hot pressing sintering and hot isostatic pressing.

[0048] Preferably, in the above preparation process, the final layer is a layer of magnesium alloy powder.

[0049] In some optional embodiments, the average particle size of the magnesium alloy powder used to prepare the biomimetic titanium alloy frame reinforced magnesium matrix composite material can be 50 μm to 100 μm, such as 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm, or other values ​​within the range of 50 μm to 100 μm. By using magnesium alloy powder with the above-mentioned average particle size, it is beneficial to fill the mesh of the titanium alloy frame more fully, thereby increasing the filling density within the mesh.

[0050] In some alternative embodiments, the thickness of the first layer of magnesium alloy powder is 2mm to 5mm, such as 2mm, 3mm, 4mm or 5mm, or other values ​​within the range of 2mm to 5mm.

[0051] More specifically, taking the laying of the second layer of magnesium alloy powder as an example, firstly, the magnesium alloy powder fully fills the mesh of the first layer of titanium alloy frame. Then, magnesium alloy powder is laid on the upper surface of the first layer of titanium alloy frame, so that the thickness of the magnesium alloy powder on the upper surface of the first layer of titanium alloy frame is h1, where h1 is 2mm to 5mm. Similarly, when laying the third layer of magnesium alloy powder, firstly, the magnesium alloy powder fully fills the mesh of the second layer of titanium alloy frame. Then, magnesium alloy powder is laid on the upper surface of the second layer of titanium alloy frame, so that the thickness of the magnesium alloy powder on the upper surface of the second layer of titanium alloy frame is h2, where h2 is 2mm to 5mm. The laying of other layers of magnesium alloy is done in the same way.

[0052] Magnesium alloy powder filling the pores of the titanium alloy frame acts as a mechanical interlock and metallurgical bond with the titanium alloy skeleton, achieving microscale reinforcement and stress transfer. Magnesium alloy powder on the upper surface of the titanium alloy frame connects the upper and lower titanium alloy frame layers, forming a continuous magnesium matrix layer, ensuring material integrity and bearing the main plastic deformation. Setting the thickness of the magnesium alloy powder on the upper surface of the titanium alloy frame to 2mm~5mm avoids problems such as incomplete continuous magnesium matrix layer, weakened interlayer bonding, and easy delamination under load due to excessive thickness. Conversely, it avoids problems such as reduced material lightweight advantages, insufficient reinforcement effect in some areas of the magnesium matrix layer, and increased potential casting or sintering defects due to excessive thickness.

[0053] More preferably, in the biomimetic titanium alloy frame reinforced magnesium matrix composite material, the thickness of the magnesium alloy matrix layer corresponding to the upper surface of each titanium alloy frame is 2.5mm~4mm.

[0054] In some alternative embodiments, the titanium alloy frame can be fabricated using 3D printing, with 3D printing conditions including: laser power of 100W~300W (e.g., 100W, 150W, 200W, 250W or 300W), and scanning speed of 500mm / s~1000mm / s (e.g., 500mm / s, 600mm / s, 700mm / s, 800mm / s or 1000mm / s).

[0055] The above 3D printing process is carried out under a protective atmosphere (such as nitrogen or argon).

[0056] In some optional embodiments, the hot pressing sintering conditions include: a pressure of 30 MPa to 50 MPa, a temperature of 500°C to 580°C, and a time of 1 to 2 hours.

[0057] The pressure for hot pressing sintering can be 30MPa, 35MPa, 40MPa, 45MPa or 50MPa, or other values ​​within the range of 30MPa to 50MPa.

[0058] The temperature for hot pressing sintering can be 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃ or 580℃, or other values ​​within the range of 500℃ to 580℃.

[0059] The hot pressing sintering time can be 1 hour, 1.5 hours, or 2 hours, or other values ​​within the range of 1 hour to 2 hours.

[0060] In the above hot pressing sintering process, the heating rate can be 5℃ / min to 10℃ / min, such as 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min or 10℃ / min, or other values ​​within the range of 5℃ / min to 10℃ / min.

[0061] In this invention, the hot-pressing sintering pressure is higher than that of conventional hot-pressing sintering, which facilitates more effective filling and densification of magnesium alloy powder. Simultaneously, it forces the magnesium alloy to fully fill all the meshes and interlayer gaps of the titanium alloy frame, establishing a tight titanium / magnesium interface contact. This lays a solid foundation for subsequent interfacial diffusion bonding and further densification through hot isostatic pressing. If the hot-pressing sintering pressure in this invention is less than 30 MPa, insufficient densification of the magnesium alloy powder is likely, resulting in more residual pores. The titanium / magnesium interface will have low bonding strength due to insufficient contact pressure, and the magnesium powder will struggle to completely fill the deep meshes of the frame, forming unfilled defects. However, if the hot-pressing sintering pressure exceeds 50 MPa, excessive pressure may cause localized crushing or deformation of the brittle titanium alloy frame (especially at the edges of its meshes), destroying the intended biomimetic structural integrity. Furthermore, excessive extrusion may lead to uneven magnesium matrix layer thickness or internal shear cracks.

[0062] After hot pressing and sintering, the temperature can be reduced at a rate of 1℃ / min to 5℃ / min (such as 1℃ / min, 3℃ / min or 5℃ / min, etc.).

[0063] Magnesium alloy powder and titanium alloy frame are molded together into a composite material by hot pressing and sintering. The magnesium alloy powder forms a magnesium alloy matrix, and the titanium alloy frame is uniformly distributed in the magnesium alloy matrix. The parts of the magnesium alloy matrix, except for the solid area of ​​the titanium alloy frame, are spatially interconnected.

[0064] In some alternative implementations, the hot isostatic pressing conditions include: a pressure of 80 MPa to 120 MPa, a temperature of 500°C to 580°C, and a time of 1.5 h to 2 h.

[0065] The pressure of hot isostatic pressing can be 80MPa, 90MPa, 100MPa, 110MPa or 120MPa, or other values ​​within the range of 80MPa to 120MPa.

[0066] The temperature for hot isostatic pressing can be 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃ or 580℃, or other values ​​within the range of 500℃ to 580℃.

[0067] The hot isostatic pressing time can be 1.5h or 2h, or other values ​​within the range of 1.5h to 2h.

[0068] During hot isostatic pressing, the heating rate can be 5℃ / min to 10℃ / min, such as 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min or 10℃ / min, or other values ​​within the range of 5℃ / min to 10℃ / min.

[0069] After hot isostatic pressing, the temperature can be reduced at a rate of 1℃ / min to 5℃ / min (e.g., 1℃ / min, 3℃ / min, or 5℃ / min). By performing the above-mentioned hot isostatic pressing treatment after hot pressing sintering, the density of the composite material can be further improved.

[0070] As mentioned above, the preparation method provided by this invention is simple to operate and easy to control, and can effectively obtain biomimetic structural titanium alloy frame reinforced magnesium matrix composite material with active densification and high strength and plasticity.

[0071] Furthermore, the present invention also provides an application of the above-mentioned biomimetic structure titanium alloy frame reinforced magnesium matrix composite material, for example, it can be used to prepare structural components.

[0072] In some alternative implementations, the structural component may, by way of example but not by way of limitation, include a mobile phone casing.

[0073] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0074] Example 1 This embodiment provides a biomimetic structural titanium alloy frame reinforced magnesium-based composite material, the preparation method of which includes: S1: Fabrication of titanium alloy frames (e.g.) Figure 1 (As shown).

[0075] Using 3D printing under the protection of high-purity argon gas, a TA15 alloy mesh frame with circular holes was printed with a laser power of 300W and a scanning speed of 500mm / s.

[0076] The thickness of each single-layer titanium alloy frame is 2mm, and the volume ratio of all mesh holes in the single-layer titanium alloy frame is 40%.

[0077] A total of 5 layers of titanium alloy frames were prepared. In order from bottom to top, the size of a single mesh in the first layer of titanium alloy frame is 0.1 mm; the size of a single mesh in the second layer of titanium alloy frame is 0.2 mm; the size of a single mesh in the third layer of titanium alloy frame is 0.3 mm; the size of a single mesh in the fourth layer of titanium alloy frame is 0.4 mm; and the size of a single mesh in the fifth layer of titanium alloy frame is 0.5 mm.

[0078] S2: Powder Lamination and Stacking In a graphite mold, a 2mm thick layer of AZ91 magnesium alloy powder (average particle size 50μm) is first laid. Then, a first layer of TA15 alloy mesh frame is placed in, and all the mesh openings of the first TA15 alloy mesh frame are filled with AZ91 magnesium alloy powder. Next, AZ91 magnesium alloy powder is laid on the upper surface of the first titanium alloy frame, so that the thickness of the AZ91 magnesium alloy powder on the upper surface of the first TA15 alloy mesh frame is 2mm. Then, a second layer of TA15 alloy mesh frame is placed in, and all the mesh openings of the second TA15 alloy mesh frame are filled with AZ91 magnesium alloy powder. Again, AZ91 magnesium alloy powder is laid on the upper surface of the second titanium alloy frame, so that the thickness of the AZ91 magnesium alloy powder on the upper surface of the second TA15 alloy mesh frame is 2mm. This process is repeated layer by layer until the preset number of layers is reached (the last layer is made of magnesium alloy powder). This step is set according to the preset volume of all titanium alloy frame solid parts being 50% of the total volume of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material.

[0079] S3: Hot pressing and sintering The mold was placed in a hot-pressing sintering furnace under high-purity argon protection and sintered for 1 hour at a pressure of 40 MPa and a temperature of 500 °C (heating rate of 5 °C / min). It was then cooled to room temperature at a rate of 5 °C / min.

[0080] S4: Hot isostatic pressing The sintered billet after hot pressing and sintering is placed into a sleeve and held at 120 MPa and 500℃ (heating rate of 6℃ / min) for 1.5 hours, and then slowly cooled (cooling rate of 3℃ / min) to room temperature.

[0081] Example 2 The difference between this embodiment and Embodiment 1 is that the mesh shape of the titanium alloy frame is rectangular (e.g., ...). Figure 2 (As shown).

[0082] Example 3 The difference between this embodiment and Embodiment 1 is that the mesh shape of the titanium alloy frame is hexagonal (e.g., ...). Figure 3 (As shown).

[0083] Example 4 The difference between this embodiment and Embodiment 1 is that the thickness of the single-layer titanium alloy frame is 1mm.

[0084] Example 5 The difference between this comparative example and Example 1 is that the thickness of the single-layer titanium alloy frame is 3mm.

[0085] Example 6 The difference between this comparative example and Example 1 is that the thickness of the AZ91 magnesium alloy powder laid on the upper surface of each titanium alloy frame is 5 mm.

[0086] Example 7 This embodiment provides a biomimetic structural titanium alloy frame reinforced magnesium-based composite material, the preparation method of which includes: S1: Fabrication of a titanium alloy frame.

[0087] Using 3D printing, under the protection of high-purity argon gas, a TA15 alloy mesh frame with circular holes was printed with a laser power of 100W and a scanning speed of 550mm / s.

[0088] The thickness of each single-layer titanium alloy frame is 2mm, and the volume ratio of all mesh holes in the single-layer titanium alloy frame is 10%.

[0089] A total of four titanium alloy frames were prepared. In order from bottom to top, the size of a single mesh in the first titanium alloy frame is 0.1 mm; the size of a single mesh in the second titanium alloy frame is 0.2 mm; the size of a single mesh in the third titanium alloy frame is 0.3 mm; and the size of a single mesh in the fourth titanium alloy frame is 0.4 mm. S2: Powder Lamination and Stacking In a graphite mold, a 2mm thick layer of AZ91 magnesium alloy powder (average particle size 80μm) is first laid. Then, a first layer of TA15 alloy mesh frame is placed in, and all the mesh openings of the first TA15 alloy mesh frame are filled with AZ91 magnesium alloy powder. Next, AZ91 magnesium alloy powder is laid on the upper surface of the first titanium alloy frame, resulting in a 2mm thickness of AZ91 magnesium alloy powder on the upper surface of the first TA15 alloy mesh frame. A second layer of TA15 alloy mesh frame is then placed in, and all the mesh openings of the second TA15 alloy mesh frame are filled with AZ91 magnesium alloy powder. Again, AZ91 magnesium alloy powder is laid on the upper surface of the second titanium alloy frame, resulting in a 2mm thickness of AZ91 magnesium alloy powder on the upper surface of the second TA15 alloy mesh frame. This process is repeated layer by layer until the preset number of layers is reached (the last layer is made of magnesium alloy powder). This step is set according to the preset volume of all titanium alloy frame solid parts being 20% ​​of the total volume of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material.

[0090] S3: Hot pressing and sintering The mold was placed in a hot-pressing sintering furnace protected by high-purity argon gas and sintered for 2 hours at a pressure of 30 MPa and a temperature of 550 °C (heating rate of 5 °C / min). Then it was cooled to room temperature at a rate of 1 °C / min.

[0091] S4: Hot isostatic pressing The sintered billet after hot pressing and sintering is placed into a sleeve and held at 80 MPa and 550℃ (heating rate of 6℃ / min) for 2 hours, and then slowly cooled (cooling rate of 3℃ / min) to room temperature.

[0092] Example 8 This embodiment provides a biomimetic structural titanium alloy frame reinforced magnesium-based composite material, the preparation method of which includes: S1: Fabrication of a titanium alloy frame.

[0093] Using 3D printing, under the protection of high-purity argon gas, a TA15 alloy mesh frame with circular holes was printed with a laser power of 200W and a scanning speed of 1000mm / s.

[0094] The thickness of each single-layer titanium alloy frame is 2mm, and the volume ratio of all mesh holes in the single-layer titanium alloy frame is 80%.

[0095] A total of three titanium alloy frames were prepared. From bottom to top, the size of a single mesh in the first titanium alloy frame was 0.1 mm; the size of a single mesh in the second titanium alloy frame was 0.2 mm; and the size of a single mesh in the third titanium alloy frame was 0.3 mm. S2: Powder Lamination and Stacking In a graphite mold, a 2mm thick layer of AZ91 magnesium alloy powder (average particle size 100μm) is first laid. Then, a first layer of TA15 alloy mesh frame is placed in, and all the mesh openings of the first TA15 alloy mesh frame are filled with AZ91 magnesium alloy powder. Next, AZ91 magnesium alloy powder is laid on the upper surface of the first titanium alloy frame, resulting in a 2mm thickness of AZ91 magnesium alloy powder on the upper surface of the first TA15 alloy mesh frame. A second layer of TA15 alloy mesh frame is then placed in, and all the mesh openings of the second TA15 alloy mesh frame are filled with AZ91 magnesium alloy powder. Again, AZ91 magnesium alloy powder is laid on the upper surface of the second titanium alloy frame, resulting in a 2mm thickness of AZ91 magnesium alloy powder on the upper surface of the second TA15 alloy mesh frame. This process is repeated layer by layer until the preset number of layers is reached (the last layer is made of magnesium alloy powder). This step is set according to the preset volume of all titanium alloy frame solid parts being 5% of the total volume of the biomimetic titanium alloy frame reinforced magnesium matrix composite material.

[0096] S3: Hot pressing and sintering The mold was placed in a hot-pressing sintering furnace under high-purity argon protection and sintered for 1 hour at a pressure of 50 MPa and a temperature of 580 °C (heating rate of 10 °C / min). It was then cooled to room temperature at a rate of 3 °C / min.

[0097] S4: Hot isostatic pressing The hot-pressed sintered billet is placed into a sleeve and held at 100 MPa and 580℃ (heating rate of 8℃ / min) for 1.5 hours, and then slowly cooled (cooling rate of 2℃ / min) to room temperature.

[0098] Comparative Example 1 The difference between this comparative example and Example 1 is that steps S2 and S3 are replaced by a melt infiltration method. Specifically, after the titanium alloy frame is prepared by 3D printing technology, the magnesium alloy is melted at 650°C and held for 2 hours. Then, the molten magnesium alloy is poured onto the titanium alloy frame and finally cooled to room temperature at a slow rate (cooling rate of 5°C / min).

[0099] Comparative Example 2 The difference between this comparative example and Example 1 is that the thickness of the single-layer titanium alloy frame is 0.5 mm.

[0100] Comparative Example 3 The difference between this comparative example and Example 1 is that the thickness of the single-layer titanium alloy frame is 5 mm.

[0101] Comparative Example 4 The difference between this comparative example and Example 1 is that the volume ratio of all mesh holes in the single-layer titanium alloy frame is 5%.

[0102] Comparative Example 5 The difference between this comparative example and Example 1 is that the volume ratio of all mesh holes in the single-layer titanium alloy frame is 85%.

[0103] Comparative Example 6 The difference between this comparative example and Example 1 is that the size of a single mesh in the titanium alloy frame is 0.05 mm.

[0104] Comparative Example 7 The difference between this comparative example and Example 1 is that the size of a single mesh in the titanium alloy frame is 1 mm.

[0105] Comparative Example 8 The difference between this comparative example and Example 1 is that the volume of all the titanium alloy frame solid parts is 2% of the total volume of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material.

[0106] Comparative Example 9 The difference between this comparative example and Example 1 is that the volume of all the titanium alloy frame solid parts is 55% of the total volume of the biomimetic structure titanium alloy frame reinforced magnesium matrix composite material.

[0107] Comparative Example 10 The difference between this comparative example and Example 1 is that the dimensions in all titanium alloy frames are the same.

[0108] Comparative Example 11 The difference between this comparative example and Example 1 is that the average particle size of the magnesium alloy powder is 20 μm.

[0109] Comparative Example 12 The difference between this comparative example and Example 1 is that the average particle size of the magnesium alloy powder is 120 μm.

[0110] Comparative Example 13 The difference between this comparative example and Example 1 is that the hot pressing sintering pressure is 25 MPa.

[0111] Comparative Example 14 The difference between this comparative example and Example 1 is that the hot pressing sintering pressure is 55 MPa.

[0112] Comparative Example 15 The difference between this comparative example and Example 1 is that the hot isostatic pressing step is omitted.

[0113] Experimental Example 1 (1) The following tests were performed on Example 1: The fracture microstructure of the biomimetic titanium alloy frame-reinforced magnesium matrix composite material obtained in Example 1 was observed by SEM, and the results are as follows: Figure 4 As shown. By Figure 4 It can be seen that the internal pores of the titanium alloy frame are circular, the magnesium matrix structure uniformly fills the pores, and the interface bonding is good.

[0114] High-magnification SEM morphology observation was performed on the magnesium matrix portion of the fracture microstructure of the biomimetic titanium alloy frame-reinforced magnesium matrix composite material obtained in Example 1. The results are as follows: Figure 5 As shown. By Figure 5 It can be seen that the magnesium matrix is ​​relatively dense, with no obvious cracks, oxides, or brittle phases precipitated.

[0115] The mechanical properties of the biomimetic titanium alloy frame-reinforced magnesium matrix composite material obtained in Example 1 were tested. The tensile strength and compressive strength are as follows: Figure 6 and Figure 7 As shown. Among them, the tensile test is conducted in accordance with GB / T 228.1-2021 "Metallic materials - Tensile testing - Part 1: Test method at room temperature", and the compression test is conducted in accordance with GB / T 7314-2017 "Metallic materials - Compression test method at room temperature".

[0116] (2) The magnesium-based composite material obtained in Comparative Example 1 was observed by SEM. The severe oxidation phenomenon inside the magnesium matrix was as follows: Figure 8 As shown.

[0117] Depend on Figure 8 It can be seen that the magnesium-based composite materials prepared by the traditional melt infiltration method exhibit severe oxidation behavior at the interface. Since the preparation temperature is within the liquid phase temperature range of magnesium, compared to the solid phase temperature of powder metallurgy, the high temperature easily leads to severe oxidation.

[0118] Experimental Example 2 The magnesium-based composite materials prepared in Examples 1-8 and Comparative Examples 1-15 were compared in terms of some mechanical properties and effects. The results are shown in Table 1.

[0119] Among them, tensile strength and elongation were tested according to GB / T 228.1-2021 "Metallic materials - Tensile testing - Part 1: Test method at room temperature", compressive strength was tested according to GB / T 7314-2017 "Metallic materials - Compression test method at room temperature", density was tested according to GB / T 5161-2014 "Determination of effective density of metal powder - Liquid impregnation method", compaction density was tested according to GB / T 231.1-2009 "General method for examination of microstructure of metallic materials", and interfacial bond strength was tested according to ASTM D1002-2010 "Standard test method for tensile shear strength of metal-to-metal bonding".

[0120] Table 1 Test Results

[0121] As can be seen from Table 1, the biomimetic titanium alloy frame reinforced magnesium-based composite materials obtained in Examples 1-8 of the present invention have higher density and mechanical properties compared with the magnesium-based composite materials obtained in Comparative Examples 1-15.

[0122] In summary, by setting the thickness of the titanium alloy frame, the mesh ratio, the mesh size, and the thickness of the magnesium alloy powder layer within a specific range, and combining hot pressing sintering and hot isostatic pressing processes, dynamic adjustment of the tensile and compressive strength of the material is achieved. The resulting biomimetic titanium alloy frame reinforced magnesium matrix composite material has high microstructure density, uniform composition, and excellent comprehensive mechanical properties, making it suitable for manufacturing structural components such as mobile phone casings.

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A biomimetic structured titanium alloy frame reinforced magnesium matrix composite material, characterized in that, The biomimetic structure titanium alloy frame reinforced magnesium matrix composite material includes a magnesium alloy matrix and a multi-layered mesh-sheet titanium alloy frame, wherein the multi-layered mesh-sheet titanium alloy frame is stacked in the magnesium alloy matrix. The volume of all the titanium alloy frame solid parts is 5% to 50% of the total volume of the biomimetic titanium alloy frame reinforced magnesium matrix composite material; The thickness of a single layer of the titanium alloy frame is 1mm to 3mm, the volume ratio of all mesh holes in the single layer of the titanium alloy frame is 10% to 80%, and the size of a single mesh hole in the titanium alloy frame is 0.1mm to 0.5mm. Along the vertical direction, the mesh size in the multi-layer titanium alloy frame gradually increases from bottom to top; the mesh size is the same in the same layer of titanium alloy frame.

2. The bionically structured titanium alloy frame reinforced magnesium matrix composite of claim 1, wherein, The shape of the mesh in the single-layer titanium alloy frame includes circular, rectangular, or hexagonal shapes.

3. The bio-inspired structured titanium alloy frame reinforced magnesium matrix composite material of claim 1 or 2, wherein, The biomimetic structure titanium alloy frame reinforced magnesium matrix composite material has at least one of the following characteristics: Feature 1 : The density of the biomimetic structured titanium alloy frame reinforced magnesium matrix composite is 1.8 g / cm 3 3.0 g / cm 3 ; Feature 2: The density of the biomimetic titanium alloy frame-reinforced magnesium matrix composite material is ≥99%; Feature 3: The interfacial bonding strength of the biomimetic titanium alloy frame reinforced magnesium matrix composite material is ≥200MPa; Feature 4: The tensile strength of the biomimetic titanium alloy frame reinforced magnesium matrix composite material is ≥600MPa; Feature 5: The compressive strength of the biomimetic titanium alloy frame reinforced magnesium matrix composite material is ≥1000MPa; Feature 6: The elongation of the biomimetic titanium alloy frame reinforced magnesium matrix composite material is ≥10%.

4. A method for preparing a biomimetic structured titanium alloy frame reinforced magnesium matrix composite material according to any one of claims 1 to 3, characterized in that, Includes the following steps: The first layer of magnesium alloy powder is laid flat, and the first layer of titanium alloy frame is placed on the first layer of magnesium alloy powder. Then, the magnesium alloy powder is laid first and the titanium alloy frame is laid in sequence until the preset number of layers is reached. Then, hot pressing sintering and hot isostatic pressing are performed.

5. The preparation method according to claim 4, characterized in that, The average particle size of the magnesium alloy powder is 50μm~100μm.

6. The preparation method according to claim 4, characterized in that, The thickness of the first layer of magnesium alloy powder is 2mm to 5mm.

7. The preparation method according to claim 4, characterized in that, The titanium alloy frame is fabricated using 3D printing. The 3D printing conditions include: laser power of 100W~300W and scanning speed of 500mm / s~1000mm / s.

8. The preparation method according to claim 7, characterized in that, 3D printing is performed under a protective atmosphere.

9. The preparation method according to claim 4, characterized in that, The hot pressing sintering conditions include: pressure of 30MPa~50MPa, temperature of 500℃~580℃, and time of 1h~2h.

10. The preparation method according to claim 9, characterized in that, During the hot pressing sintering process, the heating rate is 5℃ / min~10℃ / min.

11. The preparation method according to claim 9, characterized in that, After hot pressing and sintering, the temperature is reduced at a rate of 1℃ / min to 5℃ / min.

12. The method of claim 4, wherein, Hot isostatic pressing conditions include: pressure of 80MPa~120MPa, temperature of 500℃~580℃, and time of 1.5h~2h.

13. The method of claim 12, wherein, During hot isostatic pressing, the heating rate is 5℃ / min to 10℃ / min.

14. The method of claim 13, wherein, After hot isostatic pressing, the temperature is reduced at a rate of 1℃ / min to 5℃ / min.

15. Use of a biomimetic structured titanium alloy frame to reinforce a magnesium-based composite material according to any one of claims 1 to 3, characterized in that, The biomimetic titanium alloy frame reinforced magnesium matrix composite material is used to manufacture structural components.

16. The use according to claim 15, characterized in that, The structural component includes a mobile phone casing.

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