Ti-ni alloy frame reinforced magnesium matrix composite material and preparation method and application thereof

Abstract

This invention discloses a Ti-Ni alloy framework-reinforced magnesium matrix composite material, its preparation method, and its application, belonging to the field of magnesium alloy materials technology. The composite material comprises 10 vol.% to 40 vol.% Ti-Ni alloy framework, with the balance being a magnesium matrix; the Ti-Ni alloy framework has a porous structure, with the magnesium matrix filling the porous structure. The preparation method includes: immersing a 3D-printed Ti-Ni alloy framework cooled to room temperature into a molten magnesium matrix for vacuum infiltration, followed by vacuum heat treatment. Utilizing the shape memory function of the martensitic-austenitic phase transformation of Ti, magnesium alloy infiltration is performed in the "memory" expansion state of the titanium framework exhibiting phase transformation characteristics. Subsequent heat treatment causes the titanium framework to fully austenitize and shrink, generating a large radial compressive stress at the interface, similar to hot isostatic pressing, achieving active compaction and densification. This composite material possesses both high strength and plasticity, high density, and tight interfacial bonding.

Description

Technical Field

[0001] This invention relates to the field of magnesium alloy materials technology, and more specifically, to a Ti-Ni alloy framework reinforced magnesium matrix composite material, its preparation method, and its application. Background Technology

[0002] Against the backdrop of increasingly urgent demands for lightweight and intelligent equipment in aerospace, low-altitude economy, and other fields, traditional magnesium-based composite materials face bottlenecks such as difficulty in controlling the distribution of reinforcing phases, weak interfacial bonding, and low strength and plasticity. Existing reinforcement methods are mostly passive, making it difficult to achieve active adaptation of the structure and intelligent control of mechanical properties, especially lacking active intervention methods for the internal stress state and densification process of composite materials.

[0003] Furthermore, titanium-magnesium composite materials prepared by traditional processes have poor overall performance, exhibiting typical low strength, low plasticity, and brittle fracture, which makes the materials prone to early failure during actual service.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a Ti-Ni alloy framework reinforced magnesium matrix composite material, its preparation method and application, in order to solve or improve the above-mentioned technical problems.

[0006] This invention can be implemented as follows: In a first aspect, the present invention provides a Ti-Ni alloy framework reinforced magnesium matrix composite material, wherein, by volume percentage, the Ti-Ni alloy framework reinforced magnesium matrix composite material comprises 10% to 40% Ti-Ni alloy framework, and the balance is magnesium matrix; On an atomic percentage basis, the Ti-Ni alloy framework comprises 45% to 50% Ni and 3% to 9% Nb, with the balance being Ti; the Ti-Ni alloy framework has a porous structure and has an austenitic phase formed by the complete transformation of the martensitic phase; the magnesium matrix fills the porous structure.

[0007] In an optional implementation, the porous structure is in the form of a three-dimensional continuous mesh.

[0008] In an optional implementation, the three-dimensional continuous mesh is in the form of a lattice structure.

[0009] In an optional implementation, the lattice structure includes a three-period minimal surface.

[0010] In optional implementations, the three-period minimum surface includes Primitive, Gyroid, Diamond, or I-WP types.

[0011] In an optional embodiment, the magnesium matrix is ​​a cast magnesium alloy.

[0012] In an optional embodiment, the magnesium matrix includes at least one of WE43 magnesium alloy, AZ91 magnesium alloy, and AM80 magnesium alloy.

[0013] In an optional embodiment, the Ti-Ni alloy framework reinforced magnesium matrix composite material has at least one of the following characteristics: Feature 1: The density of the Ti-Ni alloy framework-reinforced magnesium matrix composite is 2.0 g / cm³. 3 ~3.0g / cm 3 ; Feature 2: The density of Ti-Ni alloy framework-reinforced magnesium matrix composites is ≥98%; Feature 3: The interfacial bonding strength of Ti-Ni alloy framework reinforced magnesium matrix composites is ≥150MPa; Feature 4: The tensile strength of Ti-Ni alloy framework reinforced magnesium matrix composites is ≥500MPa; Feature 5: The compressive strength of the Ti-Ni alloy framework reinforced magnesium matrix composite material is ≥800MPa; Feature 6: The elongation of Ti-Ni alloy framework reinforced magnesium matrix composites is ≥15%.

[0014] In a second aspect, the present invention provides a method for preparing a Ti-Ni alloy framework reinforced magnesium matrix composite material as described in any of the foregoing embodiments, comprising the following steps: cooling the 3D-printed Ti-Ni alloy framework to room temperature, then immersing it in a magnesium matrix melt for vacuum infiltration treatment, and then performing vacuum heat treatment.

[0015] In an optional implementation, 3D printing is performed under a protective atmosphere, and the process parameters for 3D printing include: laser power of 300W~400W, scanning speed of 1000mm / s~1200mm / s, and layer thickness of 20μm~40μm.

[0016] In an optional embodiment, the temperature of the vacuum melting infiltration treatment is 600℃~650℃, and the time of the vacuum melting infiltration treatment is 0.5h~1h.

[0017] In an optional implementation, the vacuum infiltration process is followed by cooling to room temperature.

[0018] In an optional embodiment, the cooling rate after vacuum melting treatment is 1°C / min to 5°C / min.

[0019] In an optional embodiment, vacuum heat treatment includes: treating at 80°C to 200°C for 0.5h to 2h.

[0020] In an optional embodiment, during the vacuum heat treatment process, the temperature is increased to 80°C to 200°C at a heating rate of 5°C / min to 10°C / min.

[0021] Thirdly, the present invention provides an application of the Ti-Ni alloy framework reinforced magnesium matrix composite material as described in any of the foregoing embodiments, wherein the Ti-Ni alloy framework reinforced magnesium matrix composite material is used to prepare aerospace structural components, rail transit structural components or 3C electronic devices.

[0022] The beneficial effects of this invention include: This invention uses a three-dimensional continuous mesh Ti-Ni shape memory alloy as a reinforcing framework. The reinforcement is spatially continuously distributed in the matrix through 3D printing, forming a skeletal-like biomimetic load-bearing network. Furthermore, the phase transformation properties of the shape memory alloy endow the composite material with adaptive capabilities.

[0023] The preparation method of this Ti-Ni alloy framework reinforced magnesium matrix composite material firstly obtains a Ti-Ni alloy framework by 3D printing, which is in a martensitic state at room temperature; then, the framework is subjected to magnesium alloy melt infiltration process and cooled to room temperature, where the framework remains in a martensitic state; finally, a vacuum heat treatment process is performed to transform the martensite into an austenitic phase, causing volume shrinkage and generating a large radial compressive stress similar to hot isostatic pressing at the interface, which promotes the active compaction and densification effect of the internal magnesium matrix.

[0024] The prepared Ti-Ni alloy framework reinforced magnesium matrix composite material has both high strength and plasticity, high density, and tight interfacial bonding, which can meet the application requirements of lightweight structural components. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is a macroscopic morphology image of the 3D-printed Ti-Ni alloy framework in Example 1; Figure 2 The image shows the SEM microstructure of the 3D-printed Ti-Ni alloy framework in Example 1. Figure 3 The image shows the SEM microstructure of the Ti-Ni alloy framework-reinforced magnesium matrix composite material in Example 1. Figure 4This is a magnified SEM image of the interface of the Ti-Ni alloy framework-reinforced magnesium matrix composite material in Example 1. Figure 5 This is an interface element distribution diagram of the Ti-Ni alloy framework-reinforced magnesium matrix composite material in Example 1; Figure 6 This is a tensile curve of the Ti-Ni alloy framework-reinforced magnesium matrix composite material in Example 1; Figure 7 This is a compression curve of the Ti-Ni alloy framework-reinforced magnesium matrix composite material in Example 1; Figure 8 This is a macroscopic morphology image of the 3D-printed Ti-Ni alloy framework in Example 2; Figure 9 The image shows the SEM microstructure of the 3D-printed Ti-Ni alloy framework in Example 2. Figure 10 The image shows the SEM microstructure of the Ti-Ni framework melt-infiltrated magnesium alloy in Example 2. Figure 11 The image shows the internal crack morphology of the magnesium matrix in the Ti-Ni framework melt-infiltrated magnesium alloy in Comparative Example 10. Figure 12 The image shows the pore morphology of the interface in the Ti-Ni framework melt-infiltrated magnesium alloy in Comparative Example 11. Detailed Implementation

[0027] 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.

[0028] The following is a detailed description of the Ti-Ni alloy framework reinforced magnesium matrix composite material, its preparation method, and its application provided by the present invention.

[0029] The present invention provides a Ti-Ni alloy framework reinforced magnesium matrix composite material, which comprises 10% to 40% Ti-Ni alloy framework by volume percentage, with the balance being magnesium matrix.

[0030] That is, in Ti-Ni alloy framework reinforced magnesium matrix composites, the volume percentage of Ti-Ni alloy framework can be 10%, 15%, 20%, 25%, 30%, 35% or 40%, or other values ​​within the range of 10% to 40%.

[0031] By controlling the volume fraction of the Ti-Ni alloy framework within the aforementioned range, both the strength and ductility of the alloy framework itself can be guaranteed, while the overall density remains low. If the volume fraction of the Ti-Ni alloy framework is too small, the overall density of the composite material will be high; if the volume fraction of the Ti-Ni alloy framework is too large, the strength and ductility of the framework itself will be low, which is not conducive to fully utilizing the strengthening and toughening effect of the framework reinforcement.

[0032] In this invention, the Ti-Ni alloy framework comprises 45% to 50% Ni, 3% to 9% Nb, and the balance is Ti, by atomic percentage.

[0033] In some alternative embodiments, the atomic percentage of Ni contained in the Ti-Ni alloy framework can be 45%, 46%, 47%, 48%, 49%, or 50%, or other values ​​in the range of 45% to 50%.

[0034] The atomic percentage of Ni affects the shape memory effect of the Ti-Ni framework. If the atomic percentage of Ni in the Ti-Ni alloy framework is below 45%, it is not conducive to obtaining a sufficiently high phase transformation temperature and will form a brittle phase. Ni content is the most sensitive factor in regulating the martensitic phase transformation temperature (Ms point). The lower the Ni content, the higher the phase transformation temperature. If the phase transformation temperature is too high, the subsequent heat treatment temperature will be too high, which will have a significant impact on the magnesium matrix structure. At the same time, if the atomic percentage of Ni is too low, hard and brittle Ti2Ni intermetallic compounds are easily precipitated at the grain boundaries in titanium-rich Ni-Ti alloys. These precipitates will severely cleave the matrix, significantly reduce the alloy's plasticity, toughness, and processing properties, and may become crack initiation sites, leading to brittle fracture of the material. If the atomic percentage of Ni in the Ti-Ni alloy framework is above 50%, it is easy to lead to an excessively low phase transformation temperature. For every 0.1% increase in Ni, the Ms point decreases by about 10℃. When the Ni content is too high, the Ms point may drop to far below room temperature, causing the material to remain in a stable austenitic state at room temperature, preventing martensitic transformation and thus losing the shape memory effect. Furthermore, excessive Ni content may damage the stable titanium oxide passivation layer on the surface, hindering interfacial bonding and causing excessive precipitation of nickel-rich phases such as Ni3Ti or Ni3Ti2, leading to embrittlement and fracture.

[0035] The atomic percentage of Nb in the Ti-Ni alloy framework can be 3%, 4%, 5%, 6%, 7%, 8%, or 9%, or other values ​​within the range of 3% to 9%.

[0036] The core purpose of adding Nb to Ti-Ni alloys is to prepare a shape memory alloy framework with wide hysteresis characteristics. This wide hysteresis effect (hysteresis width ΔT can reach over 100℃) mainly relies on the strong pinning effect of soft β-Nb particles formed after deformation on the martensitic reversal transformation. When the atomic percentage of Nb is below 3%, the pinning effect is weak, and the thermal hysteresis width of the alloy is similar to that of ordinary binary Ni-Ti alloys (only 20℃~30℃), failing to form a sufficient wide hysteresis effect and reducing the controllability of the phase transformation temperature. However, when the atomic percentage of Nb is above 9%, excessive Nb significantly deteriorates the material's processing performance, leading to increased hardness, strength, and deformation resistance, and a significant decrease in room temperature plasticity. Simultaneously, excessively high Nb content strongly lowers the martensitic phase transformation onset temperature (Ms point), potentially causing the alloy to remain entirely in a stable austenitic state at room temperature, thus losing the thermally induced shape memory effect. Furthermore, this leads to a sharp decrease in shape recovery and the easy precipitation of harmful brittle intermetallic compounds. These brittle phases severely hinder the phase transformation process, becoming crack initiation sites and impairing the material's toughness and fatigue life. Therefore, the Nb content must be controlled within a reasonable range to balance the wide hysteresis effect with overall performance.

[0037] In this invention, the Ti-Ni alloy framework has a porous structure and an austenitic phase formed by the complete transformation of the martensitic phase; the magnesium matrix fills the porous structure.

[0038] In some optional embodiments, the porous structure is in the form of a three-dimensional continuous mesh. Preferably, the three-dimensional continuous mesh is a lattice structure. The lattice structure can be exemplary, but not limited to, a three-period minimal surface (TPMS). A three-period minimal surface (TPMS) is a special type of lattice structure defined as a minimal surface exhibiting periodic variations in three independent directions. Periodic repeating units are generated through mathematical expressions, and these units extend infinitely in space while maintaining topological consistency, possessing the fundamental characteristic of a lattice structure forming an infinite network by translating repeating units. Exemplarily, the three-period minimal surface can be Primitive (P-type, resembling an interpenetrating array of columns), Gyroid (G-type, a complex surface with spiral interlacing), Diamond (D-type, resembling a diamond crystal structure appearing as a curve), or I-WP type. The aforementioned three-period minimal surfaces are described in related prior art.

[0039] This invention uses a three-dimensional continuous mesh Ti-Ni shape memory alloy as a reinforcing framework. The reinforcement is spatially continuously distributed in the matrix through 3D printing, forming a skeletal-like biomimetic load-bearing network. Furthermore, the phase transformation properties of the shape memory alloy endow the composite material with adaptive capabilities.

[0040] In some alternative embodiments, the magnesium matrix is ​​a cast series magnesium alloy, such as at least one of WE43 magnesium alloy, AZ91 magnesium alloy and AM80 magnesium alloy.

[0041] By using cast magnesium alloys, it is possible to achieve better fluidity and better fill the porous structure of the Ti-Ni alloy framework.

[0042] In this invention, the special structural design of the Ti-Ni alloy framework-reinforced magnesium matrix composite material can significantly improve the bonding strength and mechanical properties of the composite material.

[0043] For example, the interfacial bonding strength of this composite material is significantly improved compared to traditional particle-reinforced systems. This may be due to the combined effect of the mechanical interlocking at the nodes of the three-dimensional continuous mesh and the radial compressive stress generated by the phase transformation. In some optional embodiments, the interfacial bonding strength of the Ti-Ni alloy framework-reinforced magnesium matrix composite material is ≥150MPa, such as 150MPa~237MPa.

[0044] For example, the tensile strength of this composite material can be at least twice that of the magnesium alloy matrix, possibly because the three-dimensional continuous mesh structure can effectively transfer loads and suppress crack propagation. In some alternative embodiments, the tensile strength of the Ti-Ni alloy framework-reinforced magnesium matrix composite material is ≥500 MPa, such as 500 MPa to 620 MPa.

[0045] For example, the compressive strength of this composite material can be significantly improved compared to the magnesium alloy matrix, possibly due to the combination of the supporting effect of the three-dimensional continuous mesh unit and the phase transformation prestress. In some alternative embodiments, the compressive strength of the Ti-Ni alloy framework reinforced magnesium matrix composite material is ≥800MPa, such as 800MPa~883MPa.

[0046] For example, the composite material can maintain a high elongation during the strengthening process, which may be due to the hyperelastic deformation capability of the Ti-Ni alloy and the stress redistribution function of the grid structure. In some alternative embodiments, the elongation of the Ti-Ni alloy frame-reinforced magnesium matrix composite material is ≥15%, such as 15%~18%.

[0047] For example, the composite material exhibits high density, which may be due to the directional volume change generated during the phase transformation of the shape memory alloy, creating a continuous endogenous compressive stress field within the composite material. This stress field generates radial compaction pressure during cooling, significantly increasing the final density and reducing the porosity of the composite material. This endogenous compaction mechanism not only avoids the high cost and equipment limitations of traditional hot isostatic pressing processes but also creates a favorable compressive stress state in the interface region, significantly improving the service life of the composite material. In some optional embodiments, the density of the Ti-Ni alloy framework-reinforced magnesium matrix composite material is ≥98%, such as 98%~99.6%.

[0048] Furthermore, in some alternative embodiments, the density of the Ti-Ni alloy framework-reinforced magnesium matrix composite is 2.0 g / cm³. 3 ~3.0g / cm 3 It meets the requirements for lightweight design.

[0049] In other words, the Ti-Ni alloy framework reinforced magnesium matrix composite material provided by this invention has both high strength and plasticity, high density, and tight interfacial bonding, which can meet the application requirements of lightweight structural components.

[0050] Accordingly, the present invention also provides a method for preparing the above-mentioned Ti-Ni alloy framework reinforced magnesium matrix composite material, comprising the following steps: cooling the Ti-Ni alloy framework obtained by 3D printing to room temperature, then immersing it in the magnesium matrix melt for vacuum infiltration treatment, and then performing vacuum heat treatment.

[0051] It should be noted that each step in the preparation method provided by this invention has a decisive impact on the final performance of the composite material. If only a dense, non-connected pore Ti-Ni alloy framework is prepared by 3D printing and then magnesium alloy is melt-infiltrated, the lack of continuous, interconnected pore channels makes it difficult for the molten magnesium alloy to fully fill the interior of the framework, resulting in a large number of closed pores not filled by the matrix. This leads to a significant reduction in the actual load-bearing area of ​​the composite material, and the interfacial bonding relies only on limited external surface wetting, resulting in an interfacial bonding strength of less than 50 MPa. Without a vacuum melting process, the oxide layer and adsorbed gases on the alloy surface cannot be effectively removed. During the melting process, MgO and brittle reaction layers are easily formed at the interface, which not only hinder metallurgical bonding but also become the source of crack initiation and propagation. Without a heat treatment intelligent densification process, the composite material relies solely on natural solidification and shrinkage during melting, resulting in an internal residual porosity as high as 3% to 5%. Furthermore, the residual stress generated by the difference in thermal expansion coefficients between the Ti-Ni alloy framework and the magnesium matrix is ​​mostly tensile stress, which will further weaken the interfacial bonding and promote early failure.

[0052] The method provided by this invention first obtains a Ti-Ni alloy framework by 3D printing, which is in a martensitic state at room temperature; then, the framework is subjected to a magnesium alloy infiltration process and cooled to room temperature, where the framework remains in a martensitic state; finally, a vacuum heat treatment process is performed to transform the martensite into an austenitic phase, causing volume shrinkage and generating a large radial compressive stress similar to hot isostatic pressing at the interface, which promotes the active compaction and densification effect of the internal magnesium matrix.

[0053] In some alternative implementations, 3D printing is performed under a protective atmosphere, which may be, for example, a nitrogen atmosphere, an argon atmosphere, etc.

[0054] The laser power for 3D printing is 300W~400W, such as 300W, 320W, 350W, 380W or 400W, or other values ​​within the range of 300W~400W.

[0055] The laser power mentioned above will affect the stability of the molten pool, the forming accuracy, and the internal metallurgical quality. If the laser power is less than 300W, it is easy to cause insufficient melting of powder, resulting in incomplete fusion defects, abnormally high porosity, and decreased interlayer bonding strength. If the laser power is greater than 400W, it is easy to cause overheating of the molten pool, spheroidization, increased sputtering, and even element burn-off, grain coarsening, and deformation of the formed parts.

[0056] The scanning speed of 3D printing can be 1000mm / s to 1200mm / s, such as 1000mm / s, 1050mm / s, 1100mm / s, 1150mm / s or 1200mm / s, or other values ​​within the range of 1000mm / s to 1200mm / s.

[0057] The layer thickness of 3D printing can be 20μm~40μm, such as 20μm, 25μm, 30μm, 35μm or 40μm, or other values ​​in the range of 20μm~40μm.

[0058] It should be noted that the preparation of Ti-Ni alloy frameworks can be found in relevant existing technologies, and will not be elaborated upon here.

[0059] In some alternative embodiments, the vacuum infiltration temperature can be 600°C to 650°C, such as 600°C, 610°C, 620°C, 630°C, 640°C or 650°C, or other values ​​within the range of 600°C to 650°C.

[0060] If the vacuum infiltration temperature is below 600℃, it is not conducive to the full flow, diffusion and wetting of the matrix by the infiltrator, resulting in discontinuous infiltrated layer, uneven thickness or unfilled pores; if the vacuum infiltration temperature is above 650℃, it is not conducive to controlling the degree of interface reaction, which may lead to the formation of excessive brittle intermetallic compounds, damaging the matrix properties or causing workpiece deformation.

[0061] The vacuum melting time can be 0.5h to 1h, such as 0.5h, 0.8h or 1h, or other values ​​within the range of 0.5h to 1h.

[0062] After vacuum melting and infiltration, the material is cooled to room temperature. The cooling rate can be 1℃ / min to 5℃ / min (e.g., 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min or 5℃ / min, etc.).

[0063] If the cooling rate is too slow, it will not be conducive to suppressing the precipitation or coarsening of brittle phases, and may reduce the interfacial bonding strength and material toughness; if the cooling rate is too fast, it will not be conducive to the uniform release of stress, and may lead to crack initiation or workpiece cracking due to excessive thermal stress.

[0064] In some optional embodiments, vacuum heat treatment includes treating at 80°C to 200°C for 0.5 h to 2 h. Exemplarily, the temperature can be increased to 80°C to 200°C at a heating rate of 5°C / min to 10°C / min (e.g., 5°C / min, 8°C / min, or 10°C / min, etc.).

[0065] The vacuum heat treatment temperature can be 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, or 200℃, or other values ​​within the range of 80℃ to 200℃. In some preferred embodiments, the vacuum heat treatment temperature is 130℃ to 200℃.

[0066] The vacuum heat treatment time can be 0.5h, 0.8h, 1h, 1.5h or 2h, or other values ​​within the range of 0.5h to 2h.

[0067] The aforementioned vacuum heat treatment process can promote the transformation of the Ti-Ni alloy framework from martensite to austenite.

[0068] If the vacuum heat treatment temperature is below 80℃ or the vacuum heat treatment time is less than 0.5h, the driving force for the martensitic phase transformation will be insufficient, the phase transformation will be incomplete, and the martensitic structure cannot be fully obtained, which will seriously affect the shape memory performance of the material. If the vacuum heat treatment temperature is above 200℃ or the vacuum heat treatment time is longer than 1h, it will lead to excessive grain growth, material over-aging, and unnecessary phase decomposition or oxidation, thereby reducing the strength, fatigue life and functional stability of the material.

[0069] Building upon the above, the present invention provides a solution that enhances the performance of composite materials by combining specific materials and specific preparation processes, achieving a balance between high strength and good toughness while maintaining lightweight properties. Specifically, this includes, but is not limited to: a three-dimensional continuous mesh structure that enables efficient load transfer and uniform stress distribution; a compressive stress field generated by phase transformation that improves the interfacial bonding state and pre-suppresses micro-defects; the constraint effect of mesh elements on the matrix that inhibits local deformation and crack initiation; and the strain hardening and hyperelastic deformation of the Ti-Ni alloy itself absorbing part of the strain energy.

[0070] In addition, the present invention also provides an application of the above-mentioned Ti-Ni alloy framework reinforced magnesium matrix composite material, such as its use in the preparation of aerospace structural components, rail transit structural components or 3C electronic devices.

[0071] In some typical implementations, the aforementioned Ti-Ni alloy frame-reinforced magnesium matrix composite material can be used as a lightweight structural material for low-altitude economical aircraft.

[0072] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0073] Example 1 This embodiment provides a Ti-Ni alloy framework-reinforced magnesium matrix composite material. By volume percentage, the Ti-Ni alloy framework comprises 40% Ti-Ni alloy framework, with the balance being a magnesium matrix. By atomic percentage, the Ti-Ni alloy framework comprises 45% Ni and 3% Nb, with the balance being Ti. The Ti-Ni alloy framework has a porous structure (specifically, a D-type with a three-dimensional minimum surface, similar to a diamond crystal structure), and the Ti-Ni alloy framework has an austenitic phase formed by the complete transformation of the martensitic phase; the magnesium matrix fills the porous structure of the Ti-Ni alloy framework.

[0074] The preparation method of this Ti-Ni alloy framework reinforced magnesium matrix composite material includes: S1: 3D printed Ti-Ni alloy frame (denoted as Ti-45Ni-3Nb alloy frame).

[0075] The printing material was Ti-45Ni-3Nb alloy powder (particle size 70μm~80μm) containing 45 at.% Ni, 3 at.% Nb, and 52 at.% Ti. 3D printing was performed under a high-purity (99.99%) argon atmosphere, with a laser power of 400W, a scanning speed of 1000mm / s, and a layer thickness of 20μm.

[0076] S2: Melting and infiltrating WE43 magnesium alloy.

[0077] Under a high-purity argon protective atmosphere, the Ti-Ni alloy framework, cooled to room temperature, was slowly immersed in a magnesium alloy melt for vacuum infiltration treatment. The vacuum infiltration treatment temperature was 650°C, and the treatment time was 1 hour. Subsequently, it was slowly cooled to room temperature at a rate of 2°C / min.

[0078] S3: Intelligent compaction under vacuum heat treatment.

[0079] Heating to 150°C at a rate of 5°C / min and holding for 0.5 h promotes the complete transformation of the Ti-Ni alloy framework from martensite to austenite.

[0080] Example 2 This embodiment provides a Ti-Ni alloy framework-reinforced magnesium matrix composite material. By volume percentage, the Ti-Ni alloy framework comprises 30% Ti-Ni alloy framework, with the balance being magnesium matrix. By atomic percentage, the Ti-Ni alloy framework comprises 48% Ni and 5% Nb, with the balance being Ti. The Ti-Ni alloy framework has a porous structure (specifically, a P-type structure with three-dimensional minimum curved surfaces, resembling an interpenetrating array structure), and the Ti-Ni alloy framework has an austenitic phase formed by the complete transformation of the martensitic phase; the magnesium matrix fills the porous structure of the Ti-Ni alloy framework.

[0081] The preparation method of this Ti-Ni alloy framework reinforced magnesium matrix composite material includes: S1: 3D printed Ti-Ni alloy frame (denoted as Ti-48Ni-5Nb alloy frame).

[0082] The printing material was Ti-48Ni-5Nb alloy powder (particle size 60μm~70μm) containing 48 at.% Ni, 5 at.% Nb, and 47 at.% Ti. 3D printing was performed under a high-purity (99.99%) argon atmosphere, with a laser power of 350W, a scanning speed of 1050mm / s, and a layer thickness of 23μm.

[0083] S2: Melting infiltrated AZ91 magnesium alloy.

[0084] Under a high-purity argon protective atmosphere, the Ti-Ni alloy framework, cooled to room temperature, was slowly immersed in a magnesium alloy melt for vacuum infiltration treatment. The vacuum infiltration treatment temperature was 600℃, and the treatment time was 1 hour. Subsequently, it was slowly cooled to room temperature at a rate of 2°C / min.

[0085] S3: Intelligent compaction under vacuum heat treatment.

[0086] Heating to 180°C at a rate of 5°C / min and holding for 0.5h promotes the complete transformation of the Ti-Ni alloy framework from martensite to austenite.

[0087] Example 3 This embodiment provides a Ti-Ni alloy framework-reinforced magnesium matrix composite material. By volume percentage, the Ti-Ni alloy framework comprises 20% Ti-Ni alloy framework, with the balance being magnesium matrix. By atomic percentage, the Ti-Ni alloy framework comprises 49% Ni and 7% Nb, with the balance being Ti. The Ti-Ni alloy framework has a porous structure (specifically, a G-type three-dimensional minimum surface, similar to a complex spirally interwoven surface), and the Ti-Ni alloy framework has an austenitic phase formed by the complete transformation of the martensitic phase; the magnesium matrix fills the porous structure of the Ti-Ni alloy framework.

[0088] The preparation method of this Ti-Ni alloy framework reinforced magnesium matrix composite material includes: S1: 3D printed Ti-Ni alloy frame (denoted as Ti-49Ni-7Nb alloy frame).

[0089] The printing material was Ti-49Ni-7Nb alloy powder (particle size 50μm~60μm) containing 47 at.% Ni, 7 at.% Nb, and 46 at.% Ti. 3D printing was performed under a high-purity (99.99%) argon atmosphere, with a laser power of 300W, a scanning speed of 1000mm / s, and a layer thickness of 25μm.

[0090] S2: AM80 magnesium alloy with melting and infiltration.

[0091] Under a high-purity argon protective atmosphere, the Ti-Ni alloy framework, cooled to room temperature, was slowly immersed in a magnesium alloy melt for vacuum infiltration treatment. The vacuum infiltration treatment temperature was 650°C, and the treatment time was 1 hour. Subsequently, it was slowly cooled to room temperature at a rate of 2°C / min.

[0092] S3: Intelligent compaction under vacuum heat treatment.

[0093] Heating to 200℃ at a rate of 5°C / min and holding for 0.5h promotes the complete transformation of the Ti-Ni alloy framework from martensite to austenite.

[0094] Example 4 This embodiment provides a Ti-Ni alloy framework-reinforced magnesium matrix composite material. By volume percentage, the Ti-Ni alloy framework comprises 10% Ti-Ni alloy framework, with the balance being a magnesium matrix. By atomic percentage, the Ti-Ni alloy framework comprises 50% Ni and 9% Nb, with the balance being Ti. The Ti-Ni alloy framework has a porous structure (same as in Example 1), and the Ti-Ni alloy framework has an austenitic phase formed by the complete transformation of the martensitic phase; the magnesium matrix fills the porous structure of the Ti-Ni alloy framework.

[0095] The preparation method of this Ti-Ni alloy framework reinforced magnesium matrix composite material includes: S1: 3D printed Ti-Ni alloy frame (denoted as Ti-50Ni-9Nb alloy frame).

[0096] The printing material was Ti-50Ni-9Nb alloy powder (particle size 40μm~50 μm) containing 50 at.% Ni, 9 at.% Nb, and 41 at.% Ti. 3D printing was performed under a high-purity (99.99%) argon atmosphere, with a laser power of 350W, a scanning speed of 1050mm / s, and a layer thickness of 30 μm.

[0097] S2: Melting and infiltrating WE43 magnesium alloy.

[0098] Under a high-purity argon protective atmosphere, the Ti-Ni alloy framework, cooled to room temperature, was slowly immersed in molten magnesium alloy for vacuum infiltration treatment. The vacuum infiltration treatment temperature was 620°C, and the treatment time was 1 hour. Subsequently, it was slowly cooled to room temperature at a rate of 5°C / min.

[0099] S3: Intelligent compaction under vacuum heat treatment.

[0100] Heating to 130°C at a rate of 5°C / min and holding for 1 hour promotes the complete transformation of the Ti-Ni alloy framework from martensite to austenite.

[0101] Comparative Example 1 The difference between this comparative example and Example 1 is that in S1, the laser power for 3D printing is 100W.

[0102] Comparative Example 2 The difference between this comparative example and Example 1 is that in S1, the laser power for 3D printing is 500W.

[0103] Comparative Example 3 The difference between this comparative example and Example 1 is that in S1, the Ti-Ni alloy framework is prepared by powder metallurgy sintering, which involves mixing a pore-forming agent, a binder, and Ti alloy powder, followed by cold pressing and then heating and sintering.

[0104] Specifically, Ti alloy powder (composition of TA15) was mixed with pore-forming agent (NaCl) and binder (PEG) in a volume ratio of 85:5:10, then cold-pressed at 200 MPa for 0.5 h, and then sintered at 1100 °C and 35 MPa for 2 h.

[0105] This approach results in the inability to design a porous lattice structure for the Ti-Ni alloy framework, and the pores will be non-connected.

[0106] Comparative Example 4 The difference between this comparative example and Example 1 is that in S1, the printing material is replaced with pure Ti powder. That is, the frame is a pure Ti metal frame.

[0107] Comparative Example 5 The difference between this comparative example and Example 1 is that in S1, the printing material is an alloy powder containing 35 at.% Ni, 6 at.% Nb and 59 at.% Ti.

[0108] Comparative Example 6 The difference between this comparative example and Example 1 is that in S1, the printing material is an alloy powder containing 55 at.% Ni, 6 at.% Nb and 39 at.% Ti.

[0109] Comparative Example 7 The difference between this comparative example and Example 1 is that in S1, Nb in the printing material is replaced with Cu.

[0110] Comparative Example 8 The difference between this comparative example and Example 1 is that the volume percentage of the Ti-Ni alloy framework in the Ti-Ni alloy framework reinforced magnesium matrix composite material is 5%.

[0111] Comparative Example 9 The difference between this comparative example and Example 1 is that the Ti-Ni alloy framework accounts for 45% of the volume of the Ti-Ni alloy framework in the Ti-Ni alloy framework reinforced magnesium matrix composite.

[0112] Comparative Example 10 The difference between this comparative example and Example 1 is that in S2, the temperature of the vacuum melting magnesium treatment is 800°C, which is higher than the Ti-Ni framework phase transition temperature.

[0113] Comparative Example 11 The difference between this comparative example and Example 1 is that step S3 is omitted.

[0114] Comparative Example 12 The difference between this comparative example and Example 1 is that in S3, the vacuum heat treatment temperature is 250°C.

[0115] Experimental Example 1 (1) The following tests were performed on Example 1: The morphology of the 3D-printed Ti-Ni alloy framework in Example 1 was observed, and its macroscopic morphology is as follows: Figure 1 As shown. High-magnification SEM observation of the microstructure yielded the following results. Figure 2 As shown, by Figure 2 It can be seen that the Ti-Ni alloy framework has a uniform pore distribution, which conforms to the diamond lattice structure.

[0116] The SEM images of the microstructure of the Ti-Ni alloy framework-reinforced magnesium matrix composite material obtained in Example 1 after vacuum melting and infiltration of magnesium alloy and intelligent densification by vacuum heat treatment are shown below. Figure 3 The SEM image of the magnified microstructure of its interface is shown below. Figure 4 As shown. By Figure 3 and Figure 4 It can be seen that the magnesium-based composite material has a dense structure, good interfacial bonding, and no obvious defects such as pores and cracks.

[0117] Further EDS energy dispersive spectroscopy was performed to analyze the interfacial elemental distribution of the Ti-Ni alloy framework-reinforced magnesium matrix composite. The results are as follows: Figure 5 As shown. By Figure 5 It can be seen that the elements in the Ti-Ni alloy framework diffuse into the magnesium matrix, effectively promoting the dense bonding of the interface.

[0118] The mechanical properties of the Ti-Ni alloy framework-reinforced magnesium matrix composite were further tested, and the tensile and compressive curves are shown below. 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".

[0119] (2) The following tests were performed on Example 2: The morphology of the 3D-printed Ti-Ni alloy framework in Example 2 was observed, and its macroscopic morphology is as follows: Figure 8 As shown. High-magnification SEM observation of the microstructure yielded the following results. Figure 9 As shown in the figure. The SEM image of the microstructure of the Ti-Ni alloy framework-reinforced magnesium matrix composite material obtained in Example 2 after vacuum infiltration and vacuum heat treatment for intelligent densification is shown in the figure. Figure 10As shown, the magnesium-based composite material has a dense structure, good interfacial bonding, and no obvious defects such as pores or cracks.

[0120] (3) The following tests were performed on comparative examples 10-11: The internal crack morphology of the Ti-Ni alloy framework-reinforced magnesium matrix composite material in Comparative Example 10 was observed, and the results are as follows: Figure 11 As shown. By Figure 11 It can be seen that there are large-sized cracks in the magnesium-based composite material. Because magnesium has a large coefficient of thermal expansion, excessively high vacuum melting and infiltration temperatures can cause local stress concentration in the magnesium matrix during cooling, leading to premature fracture failure.

[0121] The interfacial pore morphology of the Ti-Ni alloy framework-reinforced magnesium matrix composite material in Comparative Example 11 was observed, and the results are as follows: Figure 12 As shown. By Figure 12 It can be seen that there are voids at the interface between the Ti-Ni framework and the magnesium matrix, and a large number of oxides and brittle precipitates are distributed there, which significantly reduces the interfacial bonding strength. This is because the Ti-Ni framework has not undergone a vacuum heat treatment process to stabilize the austenite phase, and its deformation memory recovery function is poor, resulting in a loose bond with the magnesium matrix.

[0122] Experimental Example 2 The magnesium-based composite materials prepared in Examples 1-4 and Comparative Examples 1-12 were compared in terms of some mechanical properties and effects, and the results are shown in Table 1. Tensile strength and elongation were tested according to GB / T 228.1-2021 "Metallic materials – Tensile testing – Part 1: Room temperature test method"; compressive strength was tested according to GB / T 7314-2017 "Metallic materials – Room temperature compression test method"; density was tested according to GB / T 5161-2014 "Determination of effective density of metal powders – Liquid impregnation method"; compactness was tested according to GB / T 231.1-2009 "General methods for microstructure examination of metallic materials"; and interfacial bonding strength was tested according to ASTM D1002-2010 "Standard test method for tensile and shear strength of metal-to-metal bonds".

[0123] Table 1 Comparison of microstructure and mechanical properties of magnesium-based composite materials

[0124] As can be seen from Table 1, the Ti-Ni alloy framework reinforced magnesium-based composite materials obtained in Examples 1-4 of the present invention have higher interfacial bonding strength and mechanical properties compared with the magnesium-based composite materials obtained in Comparative Examples 1-12.

[0125] In summary, this invention creatively utilizes 3D printing technology to design a spatial topological lattice structure of Ti-Ni shape memory alloy within a magnesium matrix. By leveraging its thermally induced phase transformation properties, a directional volume change in the framework is induced during vacuum heat treatment, thereby generating controllable radial compressive stress within the composite material. This achieves active densification and interface strengthening without external pressure. This method is the first to ingeniously combine the intelligent response of shape memory alloys with the preparation process of magnesium-based composite materials. It not only overcomes the functional limitations of traditional passive load-bearing reinforcement phases but also achieves active control of densification and residual stress distribution through an endogenous compaction mechanism.

[0126] 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 Ti-Ni alloy frame-reinforced magnesium-based composite material, characterized by, By volume percentage, the Ti-Ni alloy framework reinforced magnesium matrix composite material comprises 10% to 40% Ti-Ni alloy framework, with the balance being magnesium matrix; The Ti-Ni alloy framework comprises 45% to 50% Ni and 3% to 9% Nb, with the balance being Ti, by atomic percentage. The Ti-Ni alloy framework has a porous structure and has an austenitic phase formed by the complete transformation of the martensitic phase. The magnesium matrix fills the porous structure.

2. The Ti-Ni alloy frame-reinforced magnesium matrix composite material according to claim 1, characterized by, The porous structure is in the form of a three-dimensional continuous mesh.

3. The Ti-Ni alloy frame-reinforced magnesium matrix composite of claim 2, wherein The three-dimensional continuous mesh is in the form of a lattice structure.

4. The Ti-Ni alloy frame-reinforced magnesium matrix composite of claim 3, wherein The lattice structure includes a three-period minimal surface.

5. The Ti-Ni alloy frame-reinforced magnesium matrix composite of claim 4, wherein Three-period minimal surfaces include Primitive, Gyroid, Diamond, or I-WP types.

6. The Ti-Ni alloy frame-reinforced magnesium matrix composite of claim 1, wherein The magnesium matrix is ​​a cast magnesium alloy.

7. The Ti-Ni alloy frame-reinforced magnesium matrix composite of claim 6, wherein The magnesium matrix includes at least one of WE43 magnesium alloy, AZ91 magnesium alloy and AM80 magnesium alloy.

8. The Ti-Ni alloy frame-reinforced magnesium matrix composite according to any one of claims 1 to 7, characterized by, The Ti-Ni alloy framework-reinforced magnesium matrix composite material has at least one of the following characteristics: Feature 1 : The Ti-Ni alloy frame reinforced magnesium matrix composite has a density of 2.0 g / cm 3 3.0 g / cm 3 ; Feature 2: The density of the Ti-Ni alloy framework-reinforced magnesium matrix composite material is ≥98%; Feature 3: The interfacial bonding strength of the Ti-Ni alloy framework-reinforced magnesium matrix composite material is ≥150MPa; Feature 4: The tensile strength of the Ti-Ni alloy framework-reinforced magnesium matrix composite material is ≥500MPa; Feature 5: The compressive strength of the Ti-Ni alloy framework-reinforced magnesium matrix composite material is ≥800MPa; Feature 6: The elongation of the Ti-Ni alloy framework reinforced magnesium matrix composite material is ≥15%.

9. A method of producing a Ti-Ni alloy frame-reinforced magnesium-based composite material according to any one of claims 1 to 8, characterized by, The process includes the following steps: cooling the 3D-printed Ti-Ni alloy frame to room temperature, then immersing it in a magnesium matrix melt for vacuum infiltration, followed by vacuum heat treatment.

10. The method of claim 9, wherein, 3D printing is carried out under a protective atmosphere. The process parameters for 3D printing include: laser power of 300W~400W, scanning speed of 1000mm / s~1200mm / s, and layer thickness of 20μm~40μm.

11. The preparation method according to claim 9, characterized in that, The temperature for vacuum melting infiltration is 600℃~650℃, and the time for vacuum melting infiltration is 0.5h~1h.

12. The method of claim 11, wherein, After vacuum melting and infiltration, the mixture is cooled to room temperature.

13. The method of claim 11, wherein, The cooling rate after vacuum melting and infiltration treatment is 1℃ / min to 5℃ / min.

14. The method of claim 9, wherein, Vacuum heat treatment includes: treatment at 80℃~200℃ for 0.5h~2h.

15. The method of claim 14, wherein, During vacuum heat treatment, the temperature is increased to 80℃~200℃ at a heating rate of 5℃ / min~10℃ / min.

16. Use of a Ti-Ni alloy frame to reinforce a magnesium-based composite material according to any one of claims 1 to 8, characterized in that, The Ti-Ni alloy frame-reinforced magnesium matrix composite material is used to prepare aerospace structural components, rail transit structural components, or 3C electronic devices.

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