A porous metal composite based on 3D printing with a large melting-boiling point difference and application thereof

Abstract

This invention relates to the field of materials technology, specifically to a porous metal composite material with a large melting-boiling point difference based on 3D printing and its applications. This porous metal composite material is obtained by integrated 3D printing of two or more different metals with large melting-boiling point differences using multi-material L-PBF (Liquid-Pulse-Film Processing). The melting-boiling point difference between the two or more different metals is between 220 and 2000℃. During the integrated 3D printing of the multi-material L-PBF, the interface treatment uses a remelting method: a layer of metal powder to be printed is laid on the surface of the previously printed metal layer, and remelted according to the laser parameters of the layer to be printed. The porous metal composite material of this invention exhibits good interfacial compatibility and introduces no other impurities.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to a porous metal composite material with a large melting and boiling point difference based on 3D printing and its applications. Background Technology

[0002] Metal matrix composites, due to their ability to combine the excellent properties of multiple materials, such as high specific strength, high hardness, good thermal conductivity, and corrosion resistance, have shown broad application prospects in aerospace, nuclear industry, biomedicine, and electronic devices. However, traditional preparation methods, such as powder metallurgy and casting technology, have significant limitations in practical applications. On the one hand, these methods have long production cycles and high costs; on the other hand, and more critically, they are difficult to precisely control the internal structure of materials, especially the localized deployment of different materials in three-dimensional space and the construction of complex structures, thus limiting the performance optimization of components under specific working conditions.

[0003] To overcome the bottlenecks of traditional manufacturing techniques, multi-material additive manufacturing technology has emerged. This technology, with its high forming precision and unprecedented structural design flexibility, provides a new approach to achieving integrated, near-net-shape manufacturing of multi-metal composite materials. For example, bimetallic parts can be manufactured using laser powder bed melting technology, combining nickel-based superalloys with copper alloys for use in high-temperature components of aerospace engines. However, printing metals with vastly different physical properties (especially melting and boiling points) can lead to serious interface problems. During the printing process, significant thermophysical differences (typically ≥700℃) result in substantial residual thermal stress at the interface, inducing defects such as microcracks and voids. These problems severely affect the bonding quality of the interface and the final performance of the component.

[0004] Currently, strategies for solving the intermetallic interface problem with large melting and boiling point differences mainly include introducing a transition layer metal or designing a composition gradient structure. However, both methods have inherent limitations: introducing a transition layer inevitably introduces a third or more materials, which may lead to new interface problems or introduce unnecessary impurities; while composition gradient design cannot achieve clear functional zoning in most cases, causing the final component to have reduced performance in certain areas that require the superior performance of a single material, thus defeating the original purpose of multi-material composites.

[0005] Therefore, there is an urgent need in the field for an integrated preparation technology that can overcome the large differences in melting and boiling points, solve the interfacial compatibility problem, and avoid the introduction of impurities, so as to achieve the precise forming of high-performance porous metal composite materials. This has become a technical problem that needs to be solved in the field. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a porous metal composite material with a large melting-boiling point difference based on 3D printing and its application. This invention involves multi-material L-PBF integrated 3D printing of two or more different metals with a large melting-boiling point difference (220-2000℃), and then laying a layer of metal powder to be printed on the surface of the printed layer of metal material. The metal powder is then remelted according to the laser parameters of the layer to be printed, resulting in a porous metal composite material with good interfacial compatibility and no other impurities introduced.

[0007] Therefore, the present invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a porous metal composite material with a large melting-boiling point difference based on 3D printing in an optional embodiment, wherein two or more different metals with a large melting-boiling point difference are integrated into a multi-material L-PBF 3D printing process to obtain the porous metal composite material with a large melting-boiling point difference.

[0009] Among them, the melting and boiling point difference of the two or more different metals with large melting and boiling point differences is 220-2000℃;

[0010] During the integrated 3D printing of the multi-material L-PBF, the interface treatment employs a remelting method as follows:

[0011] The next layer of metal powder to be printed is spread on the surface of the already printed metal material, and then remelted according to the laser parameters of the next layer of metal material to be printed.

[0012] In this invention, the large melting-boiling point difference refers to the boiling point of one metal being less than the melting point of another metal.

[0013] Preferably, the two or more different metals with large melting and boiling point differences are selected from one of Ta-based, Ti-based, Zn-based and Mg-based metals, and more preferably Ti-based and Zn-based metals.

[0014] Furthermore, the two or more different metals with large melting and boiling point differences are Ti-based metals and Zn-based metals, respectively.

[0015] Preferably, the remelting method involves performing two laser melting processes on the interface layer between different materials during the printing process.

[0016] Preferably, the Ta-based metal is selected from one or more of pure Ta, Ta-Nb-Zr alloy, and Ta-W alloy; and / or, the Ti-based metal is selected from one or more of pure Ti, Ti6Al4V alloy, or Ti-0.3Mo-0.8Ni alloy; and / or, the steel-based alloy is selected from one or more of 304L stainless steel, 316L stainless steel, or martensitic aging steel; and / or, the Cu-based metal is selected from one or more of pure Cu, Cu-Cr-Zr alloy, or CuSn10 tin bronze; and / or, the Zn-based metal is selected from one or more of pure Zn, Zn-Mg alloy, or Zn-Li alloy; and / or, the Mg-based metal is selected from one or more of pure Mg, Mg-Zn alloy, or Mg-Al alloy; and / or, the Fe-based metal is selected from one or more of pure Fe, Fe-Mn alloy, or Fe-Ca alloy; and / or, the Mo-based metal is selected from one or more of pure Mo, Mo-Ti-Zr alloy, or TZM alloy.

[0017] Preferably, when the metal is a Ta-based metal, the laser parameters of the laser powder bed are: power 180-400W, scanning speed 100-300mm / s, and layer thickness 20-60μm; and / or, when the metal is a Ti-based metal, the laser parameters of the laser powder bed are: power 120-300W, scanning speed 200-600mm / s, and layer thickness 20-50μm; and / or, when the metal is a steel-based alloy, the laser parameters of the laser powder bed are: power 150-400W, scanning speed 150-600mm / s, and layer thickness 15-60μm; and / or, when the metal is a Zn-based metal, the laser parameters of the laser bed are: power 180-400W, scanning speed 100-300mm / s, and layer thickness 20-60μm. The laser power is 30-120W, the scanning speed is 100-800mm / s, and the layer thickness is 20-40μm; and / or, when the metal is Mg-based, the laser bed parameters are: power 40-60W, scanning speed 200-450mm / s, and layer thickness 20-40μm; and / or, when the metal is Fe-based, the laser bed parameters are: power 100-400W, scanning speed 200-800mm / s, and layer thickness 20-50μm; and / or, when the metal is Mo-based, the laser bed parameters are: power 100-500W, scanning speed 100-900mm / s, and layer thickness 20-50μm.

[0018] Furthermore, the difference in melting and boiling points between the two or more different metals with large melting and boiling point differences is between 650 and 1050°C.

[0019] Secondly, in optional embodiments, the present invention provides an application of the above-mentioned porous metal composite material based on 3D printing with a large melting and boiling point difference in the fields of biomedicine, industrial catalysis, energy storage, or aerospace.

[0020] Thirdly, in an optional embodiment, the present invention provides a heterogeneous metal bone implant, which is prepared using the above-mentioned porous metal composite material with a large melting and boiling point difference based on 3D printing.

[0021] Fourthly, in optional embodiments, the present invention provides the application of the above-mentioned heterogeneous metal bone implant in the preparation of orthopedic and / or dental metal bone implants.

[0022] Compared with the prior art, the present invention has one of the following beneficial effects:

[0023] 1. This invention achieves a porous metal composite material with good interfacial compatibility and no other impurities by performing multi-material L-PBF integrated 3D printing of two or more different metals with large melting and boiling point differences (220-2000℃), and by laying a layer of metal powder to be printed on the surface of the printed layer of metal material, and remelting according to the laser parameters of the layer of metal material to be printed.

[0024] 2. This invention selects two biocompatible metal materials with different electrode potentials and employs multi-material laser powder bed melting (L-PBF) technology. Through dynamic powder switching and interface remelting processes, metallurgical bonding is achieved at the interface of heterogeneous materials, significantly improving the interface bonding strength and fracture resistance. This ensures that heterogeneous implants with complex three-dimensional through-pore structures maintain structural integrity and functionality under harsh physiological conditions in vivo. It solves the core technical problem of weak interface bonding and easy failure in multi-material implants and addresses the issue of significant differences in melting and boiling points between the two metal materials.

[0025] 3. This invention, through an innovative interfacial remelting process, effectively overcomes the problem of uneven interfacial bonding quality caused by different printing directions. The essence of this problem lies in the significant thermophysical differences between heterogeneous materials, making the printing order crucial to the success of the interface. This process, by applying precise and controllable secondary laser scanning, actively intervenes in and reshapes the bonding process of the interfacial region, thereby breaking this directional dependence. This ensures that regardless of the printing order, equally superior interfacial performance is achieved, thus granting greater freedom in product design. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the preparation process of the heterogeneous metal bone implant provided in Embodiment 1 of the present invention;

[0028] Figure 2 The schematic diagram and general shape of the heterogeneous metal bone implant Zn / Ti designed in Embodiment 1 of the present invention;

[0029] Figure 3 The images show the microscopic characterization of the heterogeneous Zn / Ti metal bone implant prepared in Example 1 and the pure Zn metal bone implant prepared in Comparative Example 1, where a is the microscopic characterization of pure Zn, b is the microscopic characterization of Zn / Ti, and c is a schematic diagram of the interface bonding of Zn / Ti.

[0030] Figure 4 This is a microstructure diagram of the heterogeneous metal bone implant Zn / Ti prepared in Comparative Example 2 of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0032] The following examples and comparative examples all use heterogeneous metal bone implants as examples to demonstrate the preparation of porous metal composite materials.

[0033] The experimental materials and equipment involved in the examples mainly include, but are not limited to:

[0034] Reagents:

[0035] Table 1 Main Reagents

[0036]

[0037] instrument:

[0038] Table 2 Main Instruments

[0039]

[0040] The technical solution of the present invention will be described below with reference to the embodiments.

[0041] Example 1

[0042] This embodiment provides a method for preparing a porous Zn / Ti heterogeneous metal bone implant, including the following steps:

[0043] Step 1: 3D Modeling and Composition Partitioning

[0044] Based on CT data of femoral condyle bone defects in rats, a three-dimensional model was reconstructed using software. The implant size was preset to φ2.8mm × 4.8mm, and its axis was divided into two zones, each deploying one of two metals. Among biomedical metals, Ti exhibits excellent biocompatibility and mechanical properties, making it the preferred bone repair material. However, considering its non-degradability, insufficient antibacterial properties, and stress shielding risk, a biodegradable metal was introduced. This metal can gradually degrade in body fluids, promoting tissue repair through its degradation products. Zn-based metals possess biodegradability, antibacterial properties, and the ability to promote bone regeneration. Pure Zn has poor mechanical properties (yield strength of 30MPa, elongation of 2%), making it unsuitable for load-bearing bone defects. Furthermore, the degradation rate of Zn-based metals is slower than the bone regeneration rate, requiring acceleration. Therefore, this invention selects pure Ti and pure Zn for deployment in the two zones. Pure Ti zone 5 provides mechanical support, while pure Zn zone 6 degrades and provides both antibacterial and osteogenic functions.

[0045] Step 2: Design of cross-material pore structures

[0046] This invention is based on the triple-period minimum surface (TPMS) with its zero average cell curvature and large surface area. The TPMS-based scaffold has a smooth transition, enabling uniform stress distribution. It also possesses topological features and curvature similar to human bone trabeculae, thus improving tissue regeneration. Furthermore, considering the significant impact of TPMS-based scaffold pore size on biocompatibility and osteogenic activity, this invention selected a pore size of 400–600 μm as suitable for osteogenic and osteointegrative processes, and found that higher porosity leads to faster material degradation. Therefore, based on the invention's objective of accelerating degradation and promoting osteogenic growth, the pore structure chosen is the Gyriod structure from TPMS, with a porosity of 60%.

[0047] Pure Ti region 5: pore unit size 2mm, porosity 60%, adopting the Gyriod structure in TPMS.

[0048] Pure Zn region 6: pore unit size 2mm, porosity 60%, using the Gyriod structure in TPMS.

[0049] Step 3: Multi-material L-PBF printing

[0050] Pure Ti and pure Zn powders with a particle size distribution of 15~53μm were prepared by vacuum inert gas atomization. Before printing, the powders were dried at 100℃ for 5h to remove moisture. The oxygen content was controlled to ≤100ppm using an L-PBF machine under argon protection.

[0051] Laser parameters:

[0052] Pure Ti region: Laser 1 power 80W, scanning speed 450mm / s, incubation space 80μm, layer thickness 40μm.

[0053] Pure Zn region: Laser power 60W, scanning speed 350mm / s, incubation space 70μm, layer thickness 30μm.

[0054] Since Zn has a lower melting and boiling point than Ti (420℃ and 907℃ respectively), Zn evaporation during material preparation can lead to severe interfacial cracks or porosity. To address this issue, this invention employs an interfacial remelting process, which involves performing two laser scans on the Ti-Zn interface using the parameters of the material to be printed.

[0055] Material replacement process: After completing the pure Ti layer printing, replace the powder feeder with pure Zn powder 4, clean the residual pure Ti powder 2 from the forming chamber, adjust the laser parameters, and complete the material printing (see...). Figure 2 ).

[0056] Step 4: Post-processing

[0057] After the printed parts cool to room temperature, the powder in the molding chamber is recovered, the parts are separated from the substrate by wire cutting, the powder on the surface is cleaned by compressed air, and vacuum annealing is performed to optimize the mechanical properties.

[0058] Example 2

[0059] This embodiment provides a method for preparing LPBF of Ta-steel heterogeneous metal components for high-temperature aerospace parts, aiming to solve the contradictory requirements of ultra-high temperature oxidation resistance and high strength and toughness load-bearing capacity that are difficult to meet simultaneously with a single material.

[0060] Step 1: 3D Modeling and Axial Functional Zoning

[0061] Based on the service conditions of a certain type of engine turbine blade, its 3D model was reconstructed using 3D modeling software. The blade was divided into two functional blocks along the main stress direction (Z-axis of height). Given that Ta-10W alloy possesses extremely high melting points, excellent resistance to hot corrosion, and creep resistance in ultra-high temperature (>1500℃) combustion gas scouring environments, this invention selected it as the material for the high-temperature zone of the blade crown and upper blade body. Simultaneously, considering that the blade tenon needs to withstand enormous mechanical loads and connect to the impeller, maraging steel (18Ni300 steel) possesses ultra-high strength, good toughness, and fatigue performance. Based on this, this invention divides the blade into: an upper high-temperature zone (near the blade crown, material: Ta-10W alloy) and a lower load-bearing zone (tenon, material: 18Ni300 steel).

[0062] Step 2: Multi-material LPBF printing

[0063] Ta-10W and 18Ni300 steel powders with a particle size distribution of 15~53μm were prepared by vacuum inert gas atomization. Before printing, the powders were dried at 120℃ for 6h to remove moisture, and the oxygen content was controlled to ≤50ppm using an L-PBF machine under argon protection.

[0064] Laser parameters:

[0065] Ta-10W alloy region: laser power 300W, scanning speed 400mm / s, scanning spacing 100μm, layer thickness 30μm.

[0066] 18Ni300 steel zone: laser power 320W, scanning speed 900mm / s, scanning spacing 100μm, layer thickness 40μm.

[0067] Interface remelting: Select the parameters of the material to be printed to perform interface remelting.

[0068] Step 3: Post-processing

[0069] After printing, the component is cooled to below 80°C along with the forming chamber. It is then separated from the substrate using wire cutting. To eliminate residual stress and optimize performance, the component is placed in a vacuum furnace for heat treatment: first, it is heated to 850°C at a rate of 10°C / min and held for 2 hours for stress-relief annealing; then it is furnace cooled to 480°C and aged for 5 hours to strengthen the steel areas. Finally, the blade profile is precision polished.

[0070] Example 3

[0071] This embodiment provides a method for preparing an LPBF (Limited Particulate Flow) vascular stent of Fe-Mg heterogeneous metal biodegradable type. The aim is to achieve the temporal synergy of two functions, namely "rapid early endothelial healing" and "long-term radial support", through a simple axial segmentation design of the material, so as to reduce the risk of restenosis and late thrombosis.

[0072] Step 1: 3D Modeling and Axial Segmentation Design

[0073] Based on anatomical data of the rat abdominal aorta, a three-dimensional model of a rhomboid mesh vascular stent was designed. The pre-defined implant size was φ0.1mm × 5.0mm, clearly divided axially (lengthwise) into two functional segments: the "healing-promoting segments" at both ends and the "support segment" in the middle. Since the stent needs to provide continuous mechanical support for 6-12 months after implantation to prevent elastic recoil of the blood vessel, Fe-30Mn alloy (yield strength > 400 MPa) was selected as the material for the middle support segment due to its moderate and controllable degradation period (approximately 12-24 months) and excellent support strength. Simultaneously, to achieve rapid endothelialization at both ends in contact with the vessel wall after stent implantation, the material needs a faster degradation rate to release metal ions that promote endothelial cell growth. Mg-2Zn alloy was selected as the material for the healing-promoting segments at both ends due to its degradation period of approximately 3-6 months and good biocompatibility.

[0074] Step Two: Cross-Material Interface and Structural Design

[0075] The support structure has a uniform rhombic mesh topology with a pore size of 80 μm and a porosity of 70%. At the junctions, the mesh nodes are adjusted to achieve a smooth geometric transition of the mesh structure and avoid stress concentration. The Fe-30Mn alloy zone (3 mm) and the Mg-2Zn alloy zone (1 mm at each end) are directly connected by a planar metallurgical bond.

[0076] Step 3: Multi-material LPBF printing

[0077] Spherical Fe-30Mn alloy powder and Mg-2Zn alloy powder with a particle size distribution of 20-53 μm were prepared by gas atomization. The storage, transfer and loading of Mg alloy powder were completed in a glove box (oxygen content < 10 ppm).

[0078] Laser parameters:

[0079] Fe-30Mn alloy region: laser power 180W, scanning speed 1200mm / s, scanning spacing 50μm, layer thickness 20μm.

[0080] Mg-2Zn alloy region: laser power 55W, scanning speed 800mm / s, scanning spacing 40μm, layer thickness 20μm.

[0081] Interface remelting: Select the parameters of the material to be printed to perform interface remelting.

[0082] Step 4: Post-processing

[0083] After printing is complete, the bracket is removed from the substrate under the protection of a glove box.

[0084] Surface cleaning: Low-temperature plasma polishing is performed to remove powder particles adhering to the surface and obtain a smooth surface.

[0085] Example 4

[0086] This embodiment provides a method for preparing LPBF (Liquid Polymerization) Mo-Cu heterogeneous metal components for heat dissipation substrates of high-power electronic devices, aiming to achieve a reliable combination of efficient heat dissipation, high strength, and low thermal expansion through alternating layered structures.

[0087] Step 1: 3D Modeling and Alternating Layered Partition Design

[0088] A 3D model of the heat dissipation substrate was created using 3D modeling software. The substrate was designed as a layered structure along the thickness direction (Z-axis) consisting of seven alternating metal layers. Layers 1, 3, 5, and 7 are copper base layers, while layers 2, 4, and 6 are molybdenum base layers. Since the heat dissipation substrate needs to be directly connected to the ceramic package or chip, the material must have a low coefficient of thermal expansion matching that of the ceramic or silicon to prevent thermal cycling failure. Molybdenum-titanium-zirconium alloy (TZM alloy) was selected as the load-bearing and matching layer material due to its low coefficient of thermal expansion and high stiffness. Simultaneously, to rapidly diffuse the heat generated by the chip laterally to the edge heat dissipation fins, the material needs to have extremely high in-plane thermal conductivity. Chromium-zirconium-copper alloy (CuCrZr) was selected as the thermally conductive functional layer material. This "copper-molybdenum-copper" sandwich structure utilizes the copper layer for rapid heat conduction and the molybdenum layer to constrain overall expansion.

[0089] Step Two: Cross-Material Interface and Macrostructural Design

[0090] All dissimilar material interfaces are flat two-dimensional planes. Within each CuCrZr layer, a serpentine distribution of macro-grooves (1.5 mm wide and 1.0 mm deep) is designed. These grooves form naturally during printing and can be subsequently embedded with heat pipes or filled with phase change materials to further enhance heat dissipation. The TZM layer is a fully dense solid, providing the main structural rigidity. The back side of the entire substrate (the bottom CuCrZr layer) features an array of through-holes for bolt fixing.

[0091] Step 3: Multi-material LPBF printing

[0092] Spherical TZM alloy powder and CuCrZr alloy powder with a particle size distribution of 15-53 μm were prepared by gas atomization. Before printing, the powder was dried in a vacuum drying oven at 80℃ for 4 hours. Using an LPBF device equipped with a dual powder feeding system, printing was performed under argon protection (oxygen content ≤100ppm) strictly following the sequence of "from bottom to top, alternating layers".

[0093] Laser parameters:

[0094] TZM alloy layer: laser power 420W, scanning speed 320mm / s, scanning spacing 90μm, layer thickness 40μm.

[0095] CuCrZr alloy layer: laser power 380W, scanning speed 600mm / s, scanning spacing 80μm, layer thickness 30μm.

[0096] Interface remelting: Select the parameters of the material to be printed to perform interface remelting.

[0097] Step 4: Post-processing

[0098] After printing, the component is removed from the molding chamber when it cools to below 60°C. After separating the substrate by wire cutting, the following post-processing is performed:

[0099] Hot isostatic pressing: treatment in an argon atmosphere at 1100℃ and 120MPa for 3 hours to eliminate internal porosity and significantly enhance the diffusion bonding strength of the Mo-Cu interlayer interface.

[0100] Solution treatment and aging: The entire component is solution treated (980℃ / 1 hour / water quenching), followed by aging treatment (460℃ / 3 hours / air cooling) to bring the CuCrZr alloy to a balance between peak strength and thermal conductivity.

[0101] Precision machining: The upper surface of the substrate (used for chip mounting) is precision milled and polished to ensure extremely high flatness and surface finish. The pre-fabricated grooves on the back side are cleaned, and the threads for the fixing through holes are machined.

[0102] Comparative Example 1

[0103] This comparative example provides a method for preparing a pure Zn metal bone implant, including the following steps:

[0104] Step 1: 3D Modeling

[0105] Based on CT data of femoral condyle defects in rats, a three-dimensional model was reconstructed using software, with the implant size preset to φ2.8mm×4.8mm.

[0106] Step 2: Pore Structure Design

[0107] The pore unit size is 2mm, the porosity is 60%, and the Gyriod structure in TPMS is adopted.

[0108] Step 3: L-PBF Printing

[0109] Pure Zn powder with a particle size distribution of 15-53 μm was prepared by vacuum inert gas atomization. Before printing, the powder was dried at 100℃ for 5 hours to remove moisture. Printing was completed using an L-PBF machine under argon protection, with the oxygen content controlled to ≤100 ppm.

[0110] Laser parameters: laser power 60W, scanning speed 350mm / s, incubation space 70μm, layer thickness 30μm.

[0111] Step 4: Post-processing

[0112] After the printed parts cool to room temperature, the powder in the molding chamber is recovered, the parts are separated from the substrate by wire cutting, the powder on the surface is cleaned by compressed air, and vacuum annealing is performed to optimize the mechanical properties.

[0113] Comparative Example 2

[0114] This comparative example provides a method for preparing a Zn / Ti composite metal bone implant, including the following steps:

[0115] Step 1: Size Preset

[0116] The preset size is φ2.8mm×4.8mm. Its axis is divided into two sections, and two types of metals are deployed in each section.

[0117] Step 2: Design of cross-material pore structures

[0118] Pure Ti region: pore unit size 2mm, porosity 60%, using the Gyriod structure in TPMS.

[0119] Pure Zn region: pore unit size 2mm, porosity 60%, adopts the Gyriod structure in TPMS, without Zn-Ti transition layer.

[0120] Step 3: Multi-material L-PBF printing

[0121] Pure Ti and pure Zn powders with a particle size distribution of 15~53μm were prepared by vacuum inert gas atomization. Before printing, the powders were dried at 100℃ for 5h to remove moisture. The oxygen content was controlled to ≤100ppm using an L-PBF machine under argon protection.

[0122] Laser parameters:

[0123] Pure Ti region: laser power 80W, scanning speed 450mm / s, incubation space 80μm, layer thickness 40μm.

[0124] Pure Zn region: laser power 60W, scanning speed 350mm / s, incubation space 70μm, layer thickness 30μm.

[0125] The Zn-Ti interface remelting process is not performed.

[0126] Material replacement process: After completing the pure Ti layer printing, replace the powder feeder with pure Zn powder, clean the residual pure Ti powder from the forming chamber, adjust the laser parameters, and then complete the material printing (see...). Figure 2 ).

[0127] Step 4: Post-processing

[0128] After the printed parts cool to room temperature, the powder in the molding chamber is recovered, the parts are separated from the substrate by wire cutting, the powder on the surface is cleaned by compressed air, and vacuum annealing is performed to optimize the mechanical properties.

[0129] Comparative Example 3

[0130] This comparative example provides a method for preparing a Zn / Ti composite metal bone implant, including the following steps:

[0131] Sample preparation: Using the same L-PBF process parameters as in Example 1, porous composite samples with Ti-Zn interfaces were prepared.

[0132] Remelting process: The printed sample is placed in a traditional box-type heat treatment furnace protected by argon gas.

[0133] Remelting temperature: Two temperature points were set: 420℃ (slightly higher than the melting point of Zn) and 800℃ (lower than the melting point of Ti but much higher than the boiling point of Zn). The holding time for both was 30 minutes.

[0134] Results and Defect Analysis:

[0135] At 420℃: the Zn layer melts, but since the Ti layer remains solid, only a simple solid-liquid contact can be formed. Under the action of surface tension, the molten Zn cannot be stably maintained on the surface of the porous Ti framework, and it aggregates into spheres and flows, severely damaging the designed pore structure. The interface bonding area is a simple mechanical mosaic.

[0136] At 800℃, Zn not only melts completely, but its vapor pressure also rises sharply (boiling point is 907℃), causing it to evaporate and boil violently at high temperatures. This results in a large number of macroscopic pores and collapse in the porous Zn region, which separates from the Ti matrix. The interface strength is extremely low, and it crumbles with the slightest touch.

[0137] Comparative conclusion: Traditional heat treatment remelting cannot achieve localized heating and extremely fast thermal cycling. When dealing with materials with large melting and boiling point differences, it either fails to achieve effective metallurgical bonding or causes low-melting-point materials to evaporate or be lost due to excessive heat input, which completely fails to meet the requirements of precision porous components.

[0138] Experimental Example 1

[0139] The metal bone implants prepared in Examples 1-2 and Comparative Example 1 were subjected to surface treatment, material characterization, and performance testing experiments for verification.

[0140] 1. Surface treatment: The implant was ultrasonically cleaned in acetone, ethanol and deionized water for 10 min to remove loose powder remaining in the scaffold. After the sample was air-dried in an oven at 37℃, the scaffold was polished in a solution containing 5% hydrochloric acid, 5% nitric acid and 90% anhydrous ethanol for 2 min. Then the sample was ultrasonically cleaned in a solution of 10% nitric acid and 90% anhydrous ethanol for 10 s to remove residual Zn particles on the material surface. Finally, it was ultrasonically vibrated in anhydrous ethanol for 5 min to remove residual acid.

[0141] 2. Material Characterization

[0142] The morphology and elemental distribution of the surface and cross-section of the material were observed using a scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS) instrument.

[0143] Results Analysis

[0144] 1. After acid washing, the sample generally showed no excess powder in the Zn region (see [link to sample description]). Figure 2 The scanning electron microscope results show (see below) Figure 3 The Zn region surface was smooth with no unmelted powder adhering to it. No obvious cracks were observed in the interfacial bonding region of the Zn / Ti composite, indicating good bonding between Zn and Ti. Notably, a small amount of Ti was found in the Zn region near the interface, which may be due to the disturbance of the molten pool during Zn printing, causing liquid Ti to be sputtered into the Zn region.

[0145] Experimental Example 2

[0146] The metal bone implant prepared in Comparative Example 2 was characterized.

[0147] The morphology and elemental distribution of the material cross section were observed using a scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS) instrument.

[0148] Results Analysis

[0149] Scanning electron microscopy (SEM) results show that the Zn / Ti interface region exhibits an uneven structure, pores, and granular morphology. This morphology may reflect the physical morphology during material bonding, and the pores or granular defects may affect the interface's compactness and mechanical properties. Simultaneously, a large number of Ti particles are sputtered in the Zn region near the interface, making the Zn-Ti boundary indistinct (see [link to SEM]). Figure 4 ).

[0150] It is evident that when performing multi-material additive manufacturing of dissimilar materials with large differences in melting and boiling points, interfacial remelting can greatly improve the interfacial bonding of the materials.

[0151] Although the principles of the present invention have been described in detail above with reference to preferred embodiments, those skilled in the art should understand that the above embodiments are merely illustrative explanations of the implementation of the present invention and are not intended to limit the scope of the present invention. The details in the embodiments do not constitute a limitation on the scope of the present invention. Any obvious changes, such as equivalent transformations or simple substitutions, based on the technical solutions of the present invention without departing from the spirit and scope of the present invention fall within the protection scope of the present invention.

Claims

1. A porous metal composite material with a large melting-boiling point difference based on 3D printing, characterized in that, Multi-material L-PBF integrated 3D printing of two or more different metals with large melting and boiling point differences is used to obtain the porous metal composite material with large melting and boiling point differences. Among them, the melting and boiling point difference of the two or more different metals with large melting and boiling point differences is 220-2000℃; During the integrated 3D printing of the multi-material L-PBF, the interface treatment employs a remelting method as follows: The next layer of metal powder to be printed is spread on the surface of the already printed metal material, and then remelted according to the laser parameters of the next layer of metal material to be printed.

2. The porous metal composite material with a large melting and boiling point difference based on 3D printing according to claim 1, characterized in that, The two or more different metals with large melting and boiling point differences are selected from one of Ta-based, Ti-based, steel-based, Cu-based, Zn-based, Mg-based, Fe-based, and Mo-based metals.

3. The porous metal composite material with a large melting and boiling point difference based on 3D printing according to claim 1, characterized in that, The two or more different metals with large melting and boiling point differences are Ti-based metals and Zn-based metals, respectively.

4. The porous metal composite material with a large melting and boiling point difference based on 3D printing according to claim 1, characterized in that, The remelting method involves performing two laser melting processes on the interface layers of different metals during the printing process.

5. The porous metal composite material with a large melting and boiling point difference based on 3D printing according to claim 2, characterized in that, The Ta-based metal is selected from one or more of pure Ta, Ta-Nb-Zr alloys, and Ta-W alloys; and / or, The Ti-based metal is selected from one or more of pure Ti, Ti6Al4V alloy, or Ti-0.3Mo-0.8Ni alloy; and / or, The steel-based alloy is selected from one or more of 304L stainless steel, 316L stainless steel, or maraging steel; and / or The Cu-based metal is selected from one or more of pure Cu, Cu-Cr-Zr alloy, or CuSn10 tin bronze; and / or, The Zn-based metal is selected from one or more of pure Zn, Zn-Mg alloys, or Zn-Li alloys; and / or, The Mg-based metal is selected from one or more of pure Mg, Mg-Zn alloys, or Mg-Al alloys; and / or, The Fe-based metal is selected from one or more of pure Fe, Fe-Mn alloys, or Fe-Ca alloys; and / or, The Mo-based metal is selected from one or more of pure Mo, Mo-Ti-Zr alloy, or TZM alloy.

6. The porous metal composite material with a large melting and boiling point difference based on 3D printing according to claim 2, characterized in that, When the metal is a Ta-based metal, the laser parameters of the laser powder bed are: power 180-400W, scanning speed 100-500mm / s, layer thickness 20-60μm; and / or, When the metal is a Ti-based metal, the laser parameters of the laser powder bed are: power 120-300W, scanning speed 200-600mm / s, layer thickness 20-50μm; and / or, When the metal is a steel-based alloy, the laser parameters of the laser powder bed are: power 150-400W, scanning speed 150-600mm / s, layer thickness 15-60μm; and / or, When the metal is a Cu-based metal, the laser parameters of the laser powder bed are: power 200-500W, scanning speed 100-1000mm / s, layer thickness 20-50μm; and / or, When the metal is a Zn-based metal, the laser parameters of the laser bed are: power 30-120W, scanning speed 100-800mm / s, layer thickness 20-40μm; and / or, When the metal is a Mg-based metal, the laser bed parameters are: power 40-60W, scanning speed 200-450mm / s, layer thickness 20-40μm; and / or, When the metal is an Fe-based metal, the laser parameters of the laser bed are: power 100-400W, scanning speed 200-800mm / s, layer thickness 20-50μm; and / or, When the metal is a Mo-based metal, the laser parameters of the laser bed are: power 100-500W, scanning speed 100-900mm / s, and layer thickness 20-50μm.

7. The porous metal composite material with a large melting and boiling point difference based on 3D printing according to claim 1, characterized in that, The difference in melting and boiling points of the two or more different metals with large melting and boiling point differences is between 650 and 1050℃.

8. The application of a porous metal composite material with a large melting and boiling point difference based on 3D printing as described in any one of claims 1-7 in the fields of aerospace, automotive manufacturing, electronic equipment and biomedicine.

9. A heterogeneous metal bone implant, characterized in that, It is prepared using the porous metal composite material with a large melting and boiling point difference based on 3D printing as described in any one of claims 1-7.

10. The use of the heterogeneous metal bone implant of claim 9 in the preparation of orthopedic and / or dental metal bone implants.

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