High-strength porous magnesium alloys and their preparation methods

Abstract

This application discloses a high-strength porous magnesium alloy and its preparation method. The high-strength porous magnesium alloy is made of elements comprising the following mass percentages: Zn, 2-10%; Zr, 0.1-0.5%; Fe, 0.001-0.05%; Mn, 0.001-0.05%; Ni, 0.001-0.05%; 1-5% reinforcing agent; the balance being Mg; wherein the reinforcing agent is Ti-containing ceramic particles. This application improves the dense structure and mechanical properties of the porous magnesium alloy material by adding a reinforcing agent, resulting in a porous magnesium alloy with good mechanical strength. The preparation method of the high-strength porous magnesium alloy of this application can improve material preparation efficiency while reducing production costs.

Description

Technical Field

[0001] This invention relates to the field of magnesium alloys and additive manufacturing technology, and in particular to a high-strength porous magnesium alloy and its additive manufacturing method. Background Technology

[0002] Magnesium alloys are alloys composed of magnesium as a base and other alloying elements. As biomedical materials, magnesium and magnesium alloys have many advantages over existing biomedical metallic materials: ① excellent biocompatibility; ② excellent mechanical compatibility; ③ biodegradability. As biomedical materials, the unique porous structure of porous magnesium and magnesium alloys is conducive to the proliferation and growth of surrounding osteoblasts, thereby generating new bone tissue, enabling the implant to form a good bio-integration with the human body, and ultimately forming a unified whole. Furthermore, the three-dimensional interconnected pore structure of porous magnesium alloys is beneficial for the exchange and transport of nutrients and metabolites, promoting tissue regeneration and reconstruction during material degradation and absorption, and accelerating the healing process. Therefore, porous magnesium alloys are a bone tissue engineering material with promising clinical applications.

[0003] With the rapid development of laser additive manufacturing technology, more possibilities have emerged for processing customized, high-precision, and high-performance complex parts. Laser additive manufacturing can produce more porous magnesium alloy additive materials that meet specific needs. However, due to the poor structural controllability of magnesium alloys prepared by laser additive manufacturing in actual use, their mechanical properties are unstable. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] In view of this, the present invention provides a high-strength porous magnesium alloy with good structural density and good mechanical strength.

[0006] The present invention also provides an additive manufacturing method for high-strength porous magnesium alloys. This additive manufacturing method for high-strength porous magnesium alloys is simple and convenient, and can improve material preparation efficiency while reducing production costs.

[0007] According to a first aspect of the present invention, the high-strength porous magnesium alloy is mainly composed of the following elements in mass percentage: Zn, 2-10%; Zr, 0.1-0.5%; Fe, 0.001-0.05%; Mn, 0.001-0.05%; Ni, 0.001-0.05%; reinforcing agent, 1-5%; balance Mg; wherein the reinforcing agent is ceramic particles containing Ti.

[0008] The high-strength porous magnesium alloy according to embodiments of the present invention, on the one hand, incorporates a portion of Zn element within the magnesium alloy product. The addition of Zn effectively improves the grain refinement during the fabrication process of the porous magnesium alloy additive, thereby significantly enhancing the microhardness and compressive strength of the magnesium alloy additive product. Simultaneously, the solid solubility of Zn increases. According to the solid solution strengthening theory, higher solid solubility causes lattice distortion in the crystal, thus restricting dislocation slip. By increasing the solid solubility of Zn, the microhardness and mechanical properties of the porous magnesium alloy additive material are improved.

[0009] On the other hand, this application adds a reinforcing agent to the porous magnesium alloy material. Since both Ti and Mg have a close-packed hexagonal crystal structure, this can ensure a good interfacial bond between Ti and Mg. Therefore, Ti can form a dispersed reinforcing phase with high thermal stability in the magnesium alloy, thereby further improving the dense structure and mechanical properties of the porous magnesium alloy additive material, and thus enabling the final porous magnesium alloy additive product to have good mechanical strength.

[0010] The high-strength porous magnesium alloy according to embodiments of the present invention may also have the following additional technical features:

[0011] According to one embodiment of the present invention, the high-strength porous magnesium alloy is mainly composed of the following elements in mass percentage: Zn, 5-7%, Zr, 0.3-0.5%, Fe, 0.005-0.01%, Mn, 0.005-0.01%, Ni, 0.005-0.01%, and reinforcing agent, 3-5%; the balance being Mg; wherein the mass fraction of Ti in the reinforcing agent is ≥15%.

[0012] According to one embodiment of the present invention, the reinforcing agent includes any one or more of TiC, TiB2, or TiN.

[0013] According to one embodiment of the present invention, the particle size of the reinforcing agent is 15-50 μm.

[0014] According to a second aspect of the present invention, an additive manufacturing method for high-strength porous magnesium alloy includes the following steps: S1, raw material preparation: taking each component in the formula and mixing them, collecting the mixture and ball milling it, sieving and collecting the dried ball milling material; S2, substrate treatment: taking a titanium alloy plate and grinding it, using acetone as the cleaning medium, ultrasonically cleaning it and collecting the treated substrate; S3, single-layer preparation: spreading the dried ball milling material evenly on the surface of the treated substrate to form a powder layer, then placing the substrate on the surface of the worktable in the additive manufacturing device, setting the scanning path of the additive manufacturing device and starting the laser device to perform additive manufacturing; S4, repeated cladding: after the first powder layer in the additive manufacturing process is clad, lowering the worktable by one powder layer thickness and repeating step S3 until the additive manufacturing process is completed.

[0015] According to one embodiment of the present invention, in step S1, the particle size of the dried ball milling material is 45-100 μm.

[0016] According to one embodiment of the present invention, in step S2, the roughness of the treated substrate is Ra0.1~0.5μm.

[0017] According to an embodiment of the present invention, in step S3, during the additive manufacturing process, the parameters of the laser device are set to a laser power of 300W, a scanning rate of 1200mm / s, and a scanning spacing of 100μm.

[0018] According to one embodiment of the present invention, in step S3, the thickness of the powder layer is 0.2 to 0.4 mm.

[0019] According to one embodiment of the present invention, in step S3, the protective gas used in the additive manufacturing process is argon.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0021] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] The following describes in detail the high-strength porous magnesium alloy and its additive manufacturing method according to embodiments of the present invention.

[0023] First, the high-strength porous magnesium alloy according to embodiments of the present invention is mainly composed of the following elements in mass percentage: Zn, 2-10%; Zr, 0.1-0.5%; Fe, 0.001-0.05%; Mn, 0.001-0.05%; Ni, 0.001-0.05%; reinforcing agent, 1-5%; balance Mg; wherein the reinforcing agent is ceramic particles containing Ti.

[0024] Therefore, the high-strength porous magnesium alloy according to embodiments of the present invention, on the one hand, incorporates a portion of Zn element within the magnesium alloy additive material. The addition of Zn effectively improves the grain refinement during the preparation process of the porous magnesium alloy additive material, thereby significantly enhancing the microhardness and compressive properties of the magnesium alloy additive product. Simultaneously, the solid solubility of Zn element in the porous magnesium alloy matrix increases. According to the solid solution strengthening theory, higher solid solubility causes lattice distortion in the crystal, thereby restricting dislocation slip. Therefore, by increasing the solid solubility of Zn element, the microhardness and mechanical properties of the porous magnesium alloy additive material are improved.

[0025] On the other hand, this application adds a reinforcing agent to the porous magnesium alloy material. Since both Ti and Mg have a close-packed hexagonal crystal structure, this can ensure a good interfacial bond between Ti and Mg. Therefore, Ti can form a dispersed reinforcing phase with high thermal stability in the magnesium alloy, thereby further improving the dense structure and mechanical properties of the porous magnesium alloy additive material, and thus enabling the final porous magnesium alloy additive product to have good mechanical strength.

[0026] According to one embodiment of the present invention, the high-strength porous magnesium alloy is mainly composed of the following elements in mass percentage: Zn, 5-7%, Zr, 0.3-0.5%, Fe, 0.005-0.01%, Mn, 0.005-0.01%, Ni, 0.005-0.01%, and reinforcing agent, 3-5%; the balance being Mg; wherein the mass fraction of Ti in the reinforcing agent is ≥15%.

[0027] By adopting the above technical solution, this application optimizes the formulation of each component, resulting in porous magnesium alloy additives with superior mechanical properties. Simultaneously, this application limits the mass fraction of Ti in the reinforcing agent; by increasing the Ti content, the dense structure and mechanical properties of the porous magnesium alloy additive material are further improved, thus giving the final porous magnesium alloy additive material good mechanical strength.

[0028] In some specific embodiments of the present invention, the reinforcing agent includes any one or more of TiC, TiB2, or TiN.

[0029] This application optimizes the composition of the reinforcing agent. Since TiC, TiB2, or TiN have finer particle sizes, they are less prone to agglomeration, resulting in no pollution or inclusions during production. Therefore, selecting any one or more of TiC, TiB2, or TiN as the reinforcing agent can effectively improve the mechanical properties of porous magnesium alloy additive materials without producing other side effects.

[0030] In some specific embodiments of the present invention, the particle size of the reinforcing agent is 15–50 μm.

[0031] This application optimizes the particle size of the reinforcing agent. On the one hand, the reinforcing agent at this particle size will not agglomerate due to excessively low particle size. On the other hand, the reinforcing agent with optimized particle size can be more uniformly dispersed in the raw materials during the mixing process. Thus, in the process of modifying porous magnesium alloy additive materials, the uniform structure of magnesium alloy additive materials is further optimized, and the mechanical properties of magnesium alloy additive materials are improved.

[0032] This application also provides an additive manufacturing method for high-strength porous magnesium alloys, comprising the following preparation steps:

[0033] S1. Raw material preparation: Take each component in the formula and stir and mix them. Collect the mixture and ball mill it. Sieve and collect the dry ball mill material.

[0034] S2. Substrate treatment: Take a titanium alloy plate and grind it. Use acetone as the cleaning medium, ultrasonically clean it, and collect the treated substrate.

[0035] S3. Single-layer preparation: The dried ball milling material is spread evenly on the surface of the treated substrate to form a powder layer. Then, the substrate is placed on the worktable surface in the additive manufacturing device, the scanning route of the additive manufacturing device is set, and the laser device is started to carry out additive preparation.

[0036] S4. Repeated cladding: After the first powder layer in the additive manufacturing process is clad, the worktable is lowered by one powder layer thickness and step S3 is repeated until the additive manufacturing process is completed.

[0037] The technical solution of this application prepares alloy materials through laser additive manufacturing. In the laser additive manufacturing process, a high-power-density laser is used to melt and deposit the alloy powder layer by layer. This not only meets the requirements for preparing porous magnesium alloy additive materials with various structural settings, but also, according to the additive manufacturing scheme of the embodiments of this application, the prepared porous magnesium alloy additive materials have high precision and fast processing speed, which effectively improves the efficiency of additive manufacturing and reduces the cost of additive manufacturing.

[0038] According to one embodiment of the present invention, in step S1, the particle size of the dried ball milling material is 45-100 μm.

[0039] In the technical solution of this application, by fully ball milling the raw materials and optimizing their particle size, the high-speed collisions that occur during ball milling cause severe plastic deformation of the magnesium alloy powder particles, generating a large number of crystal defects such as dislocations inside the material. The lattice distortion and micro-strain increase accordingly. Due to the increased dislocation density in the high-strain region, dislocation rearrangement occurs, causing the original coarse grains to split into multiple subgrains with low-angle grain boundaries. The subgrains gradually refine and evolve into even finer grains, thereby making the structural properties of the finally prepared porous magnesium alloy additive material more superior and further improving the mechanical strength of the porous magnesium alloy additive material.

[0040] In some specific embodiments of the present invention, the roughness of the substrate after step S2 is Ra0.1~0.5μm. In the technical solution of this application, the roughness of the substrate is optimized to make its surface structure smooth, thereby improving the morphology and structure of the porous magnesium alloy forming, so that the prepared porous magnesium alloy additive has good size effect and mechanical strength.

[0041] Furthermore, in step S3, during additive manufacturing, the parameters of the laser device are set as follows: laser power of 300W, scanning rate of 1200mm / s, and scanning spacing of 100μm.

[0042] In this application, the parameters of additive manufacturing are optimized. During additive manufacturing, when the powder in the central region of the laser spot is fully melted, the powder at the edge of the spot may not absorb enough energy, resulting in incomplete melting and severe spheroidization around the pores. This reduces the mechanical properties and strength of the additive material. This application optimizes the laser power, scanning rate, and scanning spacing to reduce spheroidization to a certain extent, thereby further improving the mechanical strength and properties of the additive material.

[0043] Furthermore, in step S3, the thickness of the powder layer is 0.2–0.4 mm.

[0044] In the technical solution of this application, by optimizing the thickness of the dry ball milling material, the structural stability of the single-layer magnesium alloy additive material is improved in the actual additive manufacturing process, and the single-layer structure of the magnesium alloy is optimized, so that the porous magnesium alloy additive material finally prepared has good mechanical properties and mechanical strength.

[0045] Furthermore, the protective gas used in step S3 of the additive manufacturing process is argon.

[0046] In summary, the high-strength porous magnesium alloy additive manufacturing method of this application incorporates Zn into the magnesium alloy additive material. The addition of Zn effectively improves the grain refinement during the fabrication process, thereby enhancing the microhardness and compressive properties of the magnesium alloy additive material. Furthermore, the increased solid solubility of Zn in the porous magnesium alloy matrix, according to solid solution strengthening theory, leads to lattice distortion in the crystal, thus limiting dislocation slip. Increasing the solid solubility of Zn enhances the microhardness and mechanical properties of the porous magnesium alloy additive material.

[0047] On the other hand, this application adds a reinforcing agent to the porous magnesium alloy additive material. Since both Ti and Mg have a close-packed hexagonal crystal structure, this can ensure a good interfacial bond between Ti and Mg. Therefore, Ti can form a dispersed reinforcing phase with high thermal stability in the magnesium alloy, thereby further improving the dense structure and mechanical properties of the porous magnesium alloy additive material, and thus enabling the final porous magnesium alloy additive product to have good mechanical strength.

[0048] Meanwhile, in the preparation scheme of this application, the raw materials are thoroughly ball-milled and their particle size is optimized. The high-speed collision during ball milling causes severe plastic deformation of the magnesium alloy powder particles, generating numerous crystal defects such as dislocations within the material, resulting in a corresponding increase in lattice distortion and microstrain. Due to the increased dislocation density in the high-strain region, dislocation rearrangement occurs, causing the original coarse grains to split into multiple subgrains with low-angle grain boundaries. These subgrains gradually refine, evolving into even finer grains, thus resulting in superior structural properties of the prepared porous magnesium alloy additive material and further improving its mechanical strength.

[0049] Furthermore, the additive manufacturing parameters are optimized in this application. During additive manufacturing, when the powder in the central region of the laser spot is fully melted, the powder at the edge of the spot may not absorb enough energy, resulting in incomplete melting and severe spheroidization around the pores. This reduces the mechanical properties and strength of the additive material. This application optimizes the laser power, scanning rate, and scanning spacing to reduce spheroidization to some extent, thereby further improving the mechanical strength and properties of the additive material.

[0050] The high-strength porous magnesium alloy and its additive manufacturing method according to the present invention will be described in detail below with reference to specific embodiments.

[0051] Preparation Example

[0052] Preparation Example 1

[0053] TiC particles and TIN particles were stirred and mixed, ground, and the Ti mass fraction was adjusted to 15% to prepare reinforcing agent 1 with a particle size of 15 μm.

[0054] Preparation Example 2

[0055] TiB2 particles and TIN particles were mixed and ground, and the Ti mass fraction was adjusted to 17% to prepare reinforcing agent 2 with a particle size of 30 μm.

[0056] Preparation Example 3

[0057] TiB2 particles, TiC particles and TIN particles were mixed and ground, and the Ti mass fraction was adjusted to 20% to prepare reinforcing agent 3 with a particle size of 50 μm.

[0058] Example

[0059] Example 1

[0060] S1. Raw material preparation

[0061] By mass percentage, take 2% Zn; 0.1% Zr; 0.001% Fe; 0.001% Mn; 0.001% Ni; 1% reinforcing agent 1; and the balance is Mg. Mix the components, collect the mixture, ball mill it, sieve it, and collect the dry ball milling material with a particle size of 45 μm.

[0062] S2, Matrix Treatment

[0063] A titanium alloy plate was taken and polished to a roughness of Ra0.1μm. Acetone was used as the cleaning medium, and the plate was ultrasonically cleaned and the treated substrate was collected.

[0064] S3, Single-layer preparation

[0065] S3. Single-layer preparation: Dry ball milling material is spread evenly on the surface of the treated substrate to form a powder layer with a thickness of 0.2 mm. The substrate is then placed on the worktable surface in the additive manufacturing device. The scanning path of the additive manufacturing device is set and the laser device is started. Additive preparation is carried out in an argon atmosphere with a laser power of 300 W, a scanning rate of 1200 mm / s, a scanning spacing of 100 μm.

[0066] S4. Repeated cladding: After the first powder layer in the additive manufacturing process is clad, lower the worktable by one powder layer thickness and repeat step S3 until the additive manufacturing process is completed.

[0067] Example 2

[0068] S1. Raw material preparation

[0069] By mass percentage, take 5% Zn; 0.3% Zr; 0.005% Fe; 0.005% Mn; 0.005% Ni; 3% reinforcing agent 2; and the balance is Mg. Mix the components, collect the mixture, ball mill it, sieve it, and collect the dry ball milling material with a particle size of 80 μm.

[0070] S2, Matrix Treatment

[0071] A titanium alloy plate was taken and polished to a roughness of Ra0.2μm. Acetone was used as the cleaning medium, and the plate was ultrasonically cleaned and the treated substrate was collected.

[0072] S3. Single-layer preparation: Dry ball milling material is spread evenly on the surface of the treated substrate to form a powder layer with a thickness of 0.3 mm. The substrate is then placed on the worktable surface in the additive manufacturing device. The scanning path of the additive manufacturing device is set and the laser device is started. Additive preparation is carried out in an argon atmosphere with a laser power of 300 W, a scanning rate of 1200 mm / s, a scanning spacing of 100 μm.

[0073] S4. Repeated cladding: After the first powder layer in the additive manufacturing process is clad, lower the worktable by one powder layer thickness and repeat step S3 until the additive manufacturing process is completed.

[0074] Example 3

[0075] S1. Raw material preparation

[0076] By mass percentage, take 7% Zn; 0.5% Zr; 0.01% Fe; 0.01% Mn; 0.01% Ni; 5% reinforcing agent 3; with the balance being Mg. Mix the components, collect the mixture, ball mill it, sieve it, and collect the dry ball milling material with a particle size of 80 μm.

[0077] S2, Matrix Treatment

[0078] A titanium alloy plate was taken and polished to a roughness of Ra0.2μm. Acetone was used as the cleaning medium, and the plate was ultrasonically cleaned and the treated substrate was collected.

[0079] S3. Single-layer preparation: Dry ball milling material is spread evenly on the surface of the treated substrate to form a powder layer with a thickness of 0.3 mm. The substrate is then placed on the worktable surface in the additive manufacturing device. The scanning path of the additive manufacturing device is set and the laser device is started. Additive preparation is carried out in an argon atmosphere with a laser power of 300 W, a scanning rate of 1200 mm / s, a scanning spacing of 100 μm.

[0080] S4. Repeated cladding: After the first powder layer in the additive manufacturing process is clad, lower the worktable by one powder layer thickness and repeat step S3 until the additive manufacturing process is completed.

[0081] Example 4

[0082] S1. Raw material preparation

[0083] By mass percentage, take 10% Zn; 0.5% Zr; 0.05% Fe; 0.05% Mn; 0.05% Ni; 5% reinforcing agent 3; with the balance being Mg. Mix the components, collect the mixture, ball mill it, sieve it, and collect the dry ball milling material with a particle size of 100 μm.

[0084] S2, Matrix Treatment

[0085] A titanium alloy plate was taken and polished to a roughness of Ra0.5μm. Acetone was used as the cleaning medium, and the plate was ultrasonically cleaned and the treated substrate was collected.

[0086] S3. Single-layer preparation: Dry ball milling material is spread evenly on the surface of the treated substrate to form a powder layer with a thickness of 0.4 mm. The substrate is then placed on the worktable surface in the additive manufacturing device. The scanning path of the additive manufacturing device is set and the laser device is started. Additive preparation is carried out in an argon atmosphere with a laser power of 300 W, a scanning rate of 1200 mm / s, a scanning spacing of 100 μm.

[0087] S4. Repeated cladding: After the first powder layer in the additive manufacturing process is clad, lower the worktable by one powder layer thickness and repeat step S3 until the additive manufacturing process is completed.

[0088] Comparative Example

[0089] Comparative Example 1: A high-strength porous magnesium alloy additive was prepared. Compared with Example 1, no reinforcing agent was added to Comparative Example 1, but the other preparation conditions and component ratios were the same as those in Example 1.

[0090] Comparative Example 2: A high-strength porous magnesium alloy additive was prepared. Compared with Example 1, Comparative Example 2 used Ti particles of equal mass and particle size to replace the reinforcing agent used in Example 1. The other preparation conditions and component ratios were the same as those in Example 1.

[0091] Comparative Example 3: A high-strength porous magnesium alloy additive was prepared. Compared with Example 1, the particle size of the dry ball milling material in Comparative Example 3 was 120 μm, and the other preparation conditions and component ratios were the same as those in Example 1.

[0092] Comparative Example 4: A high-strength porous magnesium alloy additive was prepared. Compared with Example 1, the substrate was not polished during the additive preparation process of Comparative Example 4, and the other preparation conditions and component ratios were the same as those of Example 1.

[0093] Performance testing

[0094] The high-strength porous magnesium alloy additives prepared in Examples 1-4 and Comparative Examples 1-4 were subjected to performance tests.

[0095] Microhardness: The microhardness of the polished sample's cross-section and longitudinal section was measured using an HXD-1000TMC / LCD microhardness tester. A load of 50g was applied, and the holding time was 10s. To eliminate possible errors from a single measurement, the microhardness value of the sample was the average value obtained from 20 points selected on the sample surface. The microhardness used in the experiment was Vickers hardness.

[0096] Compression performance test: The compression test was carried out on an RGM-4100 electronic universal testing machine at a compression speed of 1 mm / min, and its compressive strength and elastic modulus were measured.

[0097] The experimental results are shown in the table below:

[0098] Table 1: Comparison of experimental mechanical properties of high-strength porous magnesium alloy additive manufacturing in Examples 1-4 and Comparative Examples 1-4

[0099] project Microhardness / HV Compressive strength / MPa Elastic modulus / GPa Example 1 72 125.3 1.568 Example 2 75 128.7 1.587 Example 3 78 132.4 1.593 Example 4 73 126.4 1.572 Comparative Example 1 57 105.2 1.325 Comparative Example 2 58 106.8 1.346 Comparative Example 3 61 107.6 1.385 Comparative Example 4 63 110.5 1.396

[0100] As can be seen from Table 1, the high-strength porous magnesium alloy additives prepared in Examples 1-4 have good mechanical properties. Combined with the mechanical strength data in Comparative Examples 1-2, it can be seen that the technical solution of this application adds a reinforcing agent inside the magnesium alloy additive material. Since Ti and Mg are both close-packed hexagonal crystal structures, this can ensure good interfacial bonding between Ti and Mg. Therefore, Ti can form a dispersed reinforcing phase with high thermal stability in the magnesium alloy, thereby further improving the dense structure and mechanical properties of the porous magnesium alloy additive material, so that the finally prepared porous magnesium alloy additive has good mechanical strength.

[0101] Comparative Example 3 and Example 1 were compared in terms of performance. Comparative Example 3 showed a change in the particle size of the dried ball milling material, resulting in a decrease in its mechanical properties. This demonstrates that the technical solution of this application involves thorough ball milling of the raw materials and optimization of their particle size. The high-speed collision during ball milling causes severe plastic deformation of the magnesium alloy powder particles, generating numerous dislocations and other crystal defects within the material, leading to a corresponding increase in lattice distortion and microstrain. Due to the increased dislocation density in the high-strain region, dislocation rearrangement occurs, causing the original coarse grains to split into multiple subgrains with low-angle grain boundaries. These subgrains gradually refine, evolving into even finer grains, resulting in superior structural properties of the prepared porous magnesium alloy additive material and further improving its mechanical strength.

[0102] Comparing the performance of Comparative Example 4 and Example 1, it was found that the substrate in Comparative Example 4 was not treated, which resulted in a decrease in its mechanical properties. This indicates that the technical solution of this application optimizes the roughness of the substrate, making its surface structure smooth and improving the morphology of the porous magnesium alloy. As a result, the porous magnesium alloy additive produced has good size effect and mechanical strength.

[0103] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A high-strength porous magnesium alloy prepared by additive manufacturing, characterized in that, The high-strength porous magnesium alloy is made of the following elements by mass percentage: Zn, 2-10%; Zr，0.1～0.5％； Fe, 0.001–0.05%; Mn, 0.001–0.05%; Ni, 0.001–0.05%; Enhancer, 1-5%; The balance is Mg; The reinforcing agent is a ceramic particle containing Ti, and the mass fraction of Ti in the reinforcing agent is ≥15%, and the particle size of the reinforcing agent is 15-50 μm; the reinforcing agent includes any one or more of TiB2 or TiN; The additive manufacturing method includes the following steps: S1. Raw material preparation: Take each component in the formula and stir and mix them. Collect the mixture and ball mill it. Sieve and collect the dried ball milling material. The particle size of the dried ball milling material is 45-100μm. S2. Substrate treatment: Take a titanium alloy plate and grind it. Use acetone as the cleaning medium, ultrasonically clean it, and collect the treated substrate. The roughness of the treated substrate is Ra0.1~0.2μm. S3. Single-layer preparation: The dried ball milling material is spread evenly on the surface of the treated substrate to form a powder layer. The substrate is then placed on the worktable surface of the additive manufacturing device. The scanning path of the additive manufacturing device is set and the laser device is started to perform additive preparation. In the additive preparation, the parameters of the laser device are set as follows: laser power of 300W, scanning rate of 1200mm / s, and scanning spacing of 100μm. S4. Repeated cladding: After the first powder layer in the additive manufacturing process is clad, the worktable is lowered by one powder layer thickness and step S3 is repeated until the additive manufacturing process is completed.

2. The high-strength porous magnesium alloy according to claim 1, characterized in that, The high-strength porous magnesium alloy is mainly composed of the following elements by mass percentage: Zn, 5-7%; Zr，0.3～0.5％； Fe, 0.005–0.01%; Mn, 0.005–0.01%; Ni, 0.005–0.01%; Enhancer, 3-5%; The balance is Mg.

3. A method for additive manufacturing of a high-strength porous magnesium alloy as described in any one of claims 1 to 2, characterized in that, The preparation steps include the following: S1. Raw material preparation: Take each component in the formula and stir and mix them. Collect the mixture and ball mill it. Sieve and collect the dried ball milling material. The particle size of the dried ball milling material is 45-100μm. S2. Substrate treatment: Take a titanium alloy plate and grind it. Use acetone as the cleaning medium, ultrasonically clean it, and collect the treated substrate. The roughness of the treated substrate is Ra0.1~0.2μm. S3. Single-layer preparation: The dried ball milling material is spread evenly on the surface of the treated substrate to form a powder layer. The substrate is then placed on the worktable surface of the additive manufacturing device. The scanning path of the additive manufacturing device is set and the laser device is started to perform additive preparation. In the additive preparation, the parameters of the laser device are set as follows: laser power of 300W, scanning rate of 1200mm / s, and scanning spacing of 100μm. S4. Repeated cladding: After the first powder layer in the additive manufacturing process is clad, the worktable is lowered by one powder layer thickness and step S3 is repeated until the additive manufacturing process is completed.

4. The additive manufacturing method for high-strength porous magnesium alloy according to claim 3, characterized in that, In step S3, the thickness of the powder layer is 0.2 to 0.4 mm.

5. The additive manufacturing method for high-strength porous magnesium alloy according to claim 3, characterized in that, In step S3, the protective gas used in the additive manufacturing process is argon.