Light composite metal material and preparation method thereof

Abstract

The invention belongs to the technical field of metal composite materials. The invention provides a light composite metal material. The light composite metal material comprises a bone-meat reinforcer and a skeleton reinforcer, the skeleton reinforcing body is provided with a bionic structure, and the bionic structure is a dandelion-imitating structure or a dandelion-imitating honeycomb combined structure. According to the invention, a natural biological structure is taken as a bionic object, and the strength and toughness of the light composite metal material are synergistically improved by introducing a dandelion seed umbrella-shaped structure and a honeycomb spatial layout of dandelion group arrangement. The density of the lightweight composite material prepared by the preparation method can reach 99.9%, the room-temperature tensile yield strength can reach 657 MPa, and the after-fracture uniform elongation can reach 30%. In addition, the light composite metal material has the advantages of low cost, high yield and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal composite materials, and particularly relates to a light composite metal material and a preparation method thereof. BACKGROUND

[0002] Metal materials, as the cornerstone of human social development, play an irreplaceable role in the fields of aerospace, automobile, electronics, construction, etc. With the rapid development of modern science and technology and the progress of industrial manufacturing technology, the performance of traditional metal materials in lightweight, high strength, high temperature resistance, corrosion resistance, etc. cannot fully meet the needs of high-end manufacturing fields. Especially in the aerospace, automobile engine, precision instrument and other industries, materials need to serve in extreme environments for a long time, while also having excellent comprehensive performance. Under this background, titanium-aluminum-based composite materials have gradually become a research hotspot due to their unique performance advantages, and have shown broad application prospects in high-temperature structural materials, light-weight wear-resistant materials, etc.

[0003] Titanium-aluminum alloy is a typical light-weight high-temperature structural material, which has low density, high specific strength, high-temperature oxidation resistance and corrosion resistance, and is particularly suitable for high-temperature service environments such as aircraft engine blades, combustion chamber liners, automobile turbochargers, etc. However, traditional titanium-aluminum alloys generally have low toughness, limited fatigue life and poor machinability, which limits their large-scale application. In order to improve the mechanical properties and service life of titanium-aluminum alloys, scientists have proposed a new material design idea-bionic structural materials.

[0004] The research inspiration of biomimetic materials comes from natural biological materials such as shells, bones, and nacre, which exhibit high strength, toughness, wear resistance, and excellent energy absorption capacity through unique microstructure and component interactions. The introduction of biomimetic structures not only enhances the overall performance of titanium-aluminum composite materials but also expands new possibilities for their industrial applications. First, biomimetic design can optimize the microstructure of materials by constructing nano-reinforced phases, layered structures, or interpenetrating network structures to improve the strength and toughness of materials, enabling them to maintain stable mechanical properties under high-temperature conditions. Second, biomimetic structures can effectively improve the fatigue resistance and fracture resistance of materials. Traditional metal materials are prone to crack under high-cycle fatigue and alternating load, while biomimetic structures can reduce crack propagation rates through energy dispersion mechanisms, significantly improving fatigue life. In addition, biomimetic structures can optimize the thermal physical properties of materials, enabling them to have stronger anti-creep ability under high-temperature service environments, meeting the needs of the aerospace and high-temperature manufacturing industries. In terms of application, biomimetic structure titanium-aluminum composite materials have great potential in the aerospace, automotive manufacturing, and high-end equipment manufacturing industries. For example, in the aerospace industry, this material can be used to manufacture high-temperature structural components such as turbine blades and supersonic missile shells to reduce weight and improve flight efficiency; in the automotive manufacturing industry, it can be used in engine valves, turbochargers, and other components to improve fuel efficiency and extend service life; in precision instruments and medical devices, titanium-aluminum composite materials can be used to manufacture high-precision mechanical components due to their excellent corrosion resistance.

[0005] In summary, biomimetic structure titanium-aluminum composite materials combine the microstructure advantages of natural biological materials and the high-performance characteristics of modern metal materials, providing a new solution for the next generation of lightweight, high-strength, and high-temperature-resistant structural materials. With the continuous development of advanced manufacturing technology, this type of material will play an increasingly important role in future industrial applications. Therefore, biomimetic structures of natural biological materials have become a potential approach to developing high-performance lightweight metal materials, especially as they provide new ideas for achieving synergistic enhancement of strength and fracture toughness.

[0006] CN118699068B discloses a vacuum-encapsulated rolling composite process: 2mm-thick titanium and 6mm-thick aluminum plates undergo surface texturing (Ra = 6-10μm), followed by a short-term hold at 530°C for 5 minutes under argon protection. The titanium and aluminum plates then undergo two hot rolling passes (total deformation of 57-65%). Combined with a diffusion annealing process at 300°C for 15 hours, the process achieves a measured interfacial shear strength of 163MPa (a 63% increase over conventional explosive composites), and exhibits no delamination after bending through 180°. However, due to the limitations of solid-state rolling, the interfacial transition layer is only 4-6μm thick, and the brittle TiAl₃ phase is not fully suppressed. The cyclic corrosion current density is 0.85μA / cm² (greater than the aerospace standard of 0.5μA / cm²). Furthermore, the vacuum-encapsulated welding tooling is complex (involving 16 sets of cylinder linkages), resulting in a mass production rate of ≤5 tons / day. CN119530587A discloses a method for preparing a titanium-aluminum composite material by ball milling-hot isostatic pressing: titanium powder (D50 = 5-50 μm) and aluminum powder (D50 = 5-65 μm) are ball milled and mixed for 12-48 hours in a mass ratio of 1-5:1, and then molded. The mold size is diameter (250-350 mm) × thickness (450 mm-550 mm), and the mold density is 51-65%. Then, hot isostatic pressing is performed at 300-500 ° C and 100-120 MPa for 2-7 hours. This method enables the preparation of large-scale green bodies (Φ350×550mm) with a density of up to 99% (porosity <1%), making it suitable for sputtering targets. However, its process cycle is as long as 55 hours (ball milling + hot pressing), and the powder cost accounts for 70% of the total material cost. Moreover, due to the difference in melting points between titanium and aluminum (Ti: 1668°C, Al: 660°C), a composition segregation band (width >20μm) exists at the interface. CN119704799B discloses an innovative liquid aluminum sandwich casting method: titanium foil thinned to 0.015-0.06mm by rolling is preheated to 600°C, and molten aluminum at 680°C is injected. The spacing between the two solid titanium sheets is 0.09-0.36mm. The semi-solid composite material is then diffused at 420°C / 40min and cold rolled in multiple passes (deformation per pass ≤20%). This method successfully produced ultra-thin titanium-aluminum layered metal composite plates (0.05-0.2mm), with an interface transition layer thickness of 3-6μm, a resistance of ≤10.5μΩ·cm, and a bending strength of ≥140MPa. However, the process window is extremely narrow, and cold rolling requires an ultra-high pressure of 500MPa (increasing roller loss by 300%), making it only suitable for micro-nano devices such as micro fuel cell bipolar plates. The NAMP process of the Institute of Metal Research, Chinese Academy of Sciences, has disclosed a 3D printing technology that eliminates pores and refines the structure. Through the step-by-step implementation of hot isostatic pressing (eliminating pores to <0.01%) and sub-second pulsed laser remelting (refining grains to 10-20μm), the fatigue strength of Ti-6Al-4V reaches 978MPa (conventional hot isostatic pressing parts are only 520MPa).The service life of the aero-engine blade is increased by 300% through 15000 cycle load tests, but the high-energy beam melting is prone to porosity / unfused defects, and the subsequent hot isostatic pressing can eliminate the porosity but cause the organization to be coarse, so that the two targets are optimized by step-by-step control. Therefore, the development trend at the present stage changes from single performance optimization to three-dimensional cooperation of "gradient interface-defect control-topology innovation", and the problems of NAMP process mass production bottleneck and multi-material integration of titanium-aluminum interpenetrating network structure (oxygen sensitivity control) need to be solved.

[0007] In summary of the above research, although the existing titanium-aluminum composite materials improve the interface bonding force and material performance through different methods, there are still problems of large brittleness, complex process, high cost and the like. Therefore, developing a new type of titanium-aluminum bionic composite material with optimized structure, controllable process, low cost and excellent mechanical properties and a preparation method thereof has important significance for promoting the industrial application of the material. SUMMARY

[0008] The purpose of the present application is to provide a light composite metal material which has high strength and high toughness by specific bionic structure design. In addition, the present application also provides a preparation method of the light composite metal material to ensure the uniformity and stability of the composite metal material.

[0009] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions: The present application provides a light composite metal material comprising a bone-meat reinforcing body and a skeleton reinforcing body. The skeleton reinforcing body has a bionic structure which is a bionic dandelion structure or a bionic dandelion honeycomb combined structure.

[0010] Preferably, the material of the skeleton reinforcing body is titanium alloy with a particle size of 20-37 μm, and the material of the bone-meat reinforcing body is aluminum alloy.

[0011] Preferably, when the bionic structure is a bionic dandelion structure, the skeleton reinforcing body is composed of a plurality of spatial network structures stacked in layers. The spatial network structure is composed of a plurality of branches connected to each other. The plurality of branches are a plurality of branches extending radially outward from the core node.

[0012] Preferably, the branch level of the plurality of branches is 3, the length of each single branch is 0.4-0.5 mm, the diameter of the branch decreases step by step along the radial direction from the core outward, the diameter of the first branch is 0.2-0.3 mm, the diameter of the last branch is 0.15-0.2 mm, and the radial distance between adjacent branches is 0.2-0.4 mm. The stacking units of the space network structure are periodically arranged in the axial direction, and the center distance of adjacent stacking units is 0.4-0.6 mm.

[0013] As preferred, when the biomimetic structure is a dandelion-like honeycomb combined structure, the skeleton reinforcing body is a three-level toughened skeleton. The three-level toughened skeleton is composed of a plurality of second-level honeycomb networks arranged in a staggered stack along the axial direction, and the basic cells of adjacent second-level honeycomb networks are arranged in a 60-90° rotational stagger. The second-level honeycomb network is composed of a plurality of branch ends of basic cells connected to each other, and the center distance of adjacent basic cells is 2-6 mm. The basic cell is composed of a radial branch unit.

[0014] As preferred, the basic cell is composed of a main branch extending three-dimensionally radially from a central core, the number of main branches is 3-6, the length of the main branch is 0.8-2 mm, the root diameter of the main branch is 0.2-0.4 mm, and the tip diameter of the main branch is 0.02-0.1 mm. The main branch branches into a secondary branch to form a space network structure, and each main branch branches into The number of secondary branches is 2-3, and the length of the secondary branch is 0.4-1 mm. Adjacent second-level honeycomb networks are connected through natural crosslinking points of branches, and the equivalent connection length of the branch crosslinking point is 0.4-0.8 mm.

[0015] As preferred, the mass percentage of the skeleton reinforcing body is 30-50%, and the rest is the flesh reinforcing body.

[0016] The application also provides a preparation method of the lightweight composite metal material, comprising the following steps: 1) Design and establish a three-dimensional model of a skeleton reinforcing body with a dandelion-like structure or a dandelion-like honeycomb combined structure through Solidworks modeling software; 2) Prepare the skeleton reinforcing body by selective laser melting 3D printing; 3) Perform sintering treatment on the skeleton reinforcing body and the flesh reinforcing body to obtain a lightweight composite metal material.

[0017] As preferred, the parameters of the selective laser melting 3D printing in step 2) are as follows: the laser power is 200-400 W, the scanning speed is 1000-1250 mm / s, the scanning interval is 60-100 μm, the powder laying thickness is 20-30 μm, the preheating temperature of the substrate is 120-130 °C, the temperature of the powder tank is 110-115 °C, and the printing layer thickness is ≤30 μm.

[0018] Preferably, the infiltration treatment is performed under electromagnetic stirring, the frequency of the electromagnetic stirring is 45-50 Hz, and the current intensity is 100-150 A; The temperature of the infiltration treatment is 720-800 DEG C, the time of the infiltration treatment is 15-45 min, and the heating rate for heating to the temperature of the infiltration treatment is 20-30 DEG C / min.

[0019] The present application has the following advantages: 1) The present application takes natural biological structure as the bionic object, realizes the synergistic promotion of the strength and toughness of the lightweight composite metal material by introducing the umbrella-shaped structure of the dandelion seed and the honeycomb-like spatial layout of the dandelion colony. The umbrella-shaped ray structure of the dandelion can realize the multidirectional diffusion and dispersion of the load, and has excellent impact resistance and energy absorption capacity; and the dandelion honeycomb structure simulates the characteristics of close arrangement and high space utilization in nature, and can enhance the stability and force transmission uniformity in three-dimensional directions.

[0020] 2) The material of the skeleton reinforcing body in the present application is titanium alloy, the flowability index of the titanium alloy powder is > 85%, the composition is stable, and the mature SLM process is matched, so that the accurate design and control can be realized, and the yield is high.

[0021] 3) The introduction of the bionic structure in the present application not only optimizes the stress transmission path, but also activates the toughening mechanisms such as crack deflection, crack passivation and multi-path expansion, so as to realize the toughening of the overall structure. At the same time, the skeleton reinforcing body and the flesh reinforcing body are interconnected in three-dimensional space, so as to ensure the stable release and synergistic enhancement of the mechanical properties.

[0022] 4) In the present application, the lightweight composite metal material takes high-melting-point titanium alloy as the skeleton reinforcing body material, and low-melting-point and lightweight aluminum alloy as the flesh reinforcing body material, which not only has the advantage of lower cost compared with traditional titanium alloy, but also can realize the interphase composite structure with high density through the infiltration process. The difference in melting point between the two materials is more than twice, which can effectively prevent the skeleton from deforming or melting during the infiltration process.

[0023] 5) The lightweight composite metal material prepared by the preparation method of the present application has good density and excellent comprehensive performance in mechanical properties such as strength and plasticity. The density of the lightweight composite metal material can reach 99.9%, the tensile yield strength at room temperature can reach 657 MPa, and the uniform elongation after fracture can reach 30%. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a three-dimensional model cell diagram of the lightweight composite metal material with dandelion structure obtained in Example 1; Figure 2 It is a three-dimensional model diagram of the dandelion structure skeleton reinforcing body in Example 1. Figure 3 This is a graph showing the tensile mechanical properties of the dandelion-like structure skeleton reinforcement in Example 1; Figure 4 This is a three-dimensional model diagram of the dandelion-like honeycomb combined structure skeleton reinforcement body in Example 2; Figure 5 This is a graph showing the tensile mechanical properties of the dandelion-like honeycomb combined structure skeleton reinforcement in Example 2; Figure 6 This is a three-dimensional model diagram of the lightweight composite metal material with a dandelion-like honeycomb structure obtained in Example 2; Figure 7 This is a microscopic morphology of the interface between the dandelion-like honeycomb combined structure skeleton reinforcement and the bone-flesh reinforcement in Example 2. DETAILED DESCRIPTION

[0025] The present invention provides a lightweight composite metal material, which includes a flesh reinforcement body and a skeleton reinforcement body; The skeleton reinforcement body has a bionic structure, and the bionic structure is a dandelion-like structure or a dandelion-like honeycomb-combined structure.

[0026] In the present invention, the material of the skeleton reinforcement is preferably titanium alloy, more preferably Ti-6Al-4V, and the particle size of the titanium alloy is preferably 20-37 μm, more preferably 25-30 μm, and more preferably 22-23 μm; The material of the bone reinforcement is preferably aluminum alloy, more preferably 5 series aluminum alloy, and more preferably 5 series aluminum alloy 5052 and 5 series aluminum alloy 5083.

[0027] In the present invention, when the bionic structure is a dandelion-like structure, the skeleton reinforcement is preferably composed of a plurality of space network structures stacked in layers; The spatial network structure is preferably composed of multiple levels of branches connected to each other; The multi-level branches are preferably multi-level branches that extend three-dimensionally from a core node.

[0028] In the present invention, the porosity of the spatial network structure is preferably 40 to 70%, and more preferably 50~60%, more preferably 55%.

[0029] In the present invention, the number of branches of the multi-level branches is preferably 3, and the length of each single-level branch is The diameter of the core is preferably 0.4-0.5 mm, further preferably 0.44-0.46 mm, and more preferably 0.45 mm; the diameter of the branch is preferably gradually decreased in the radial direction from the core, the diameter of the primary branch is preferably 0.2-0.3 mm, further preferably 0.24-0.26 mm, and more preferably 0.25 mm, the diameter of the final branch is preferably 0.15-0.2 mm, further preferably 0.16-0.18 mm, and more preferably 0.17 mm, and the radial distance between adjacent branches is preferably 0.2-0.4 mm, further preferably 0.25-0.35 mm, and more preferably 0.3 mm; The stacking units of the spatial network structure are preferably periodically arranged in the axial direction, and the center distance between adjacent stacking units is preferably 0.4-0.6 mm, further preferably 0.45-0.55 mm, and more preferably 0.5 mm.

[0030] In the present application, when the bionic structure is a dandelion honeycomb combined structure, the skeleton reinforcing body is preferably a three-stage toughened skeleton. The three-stage toughened skeleton is preferably composed of a plurality of secondary honeycomb networks arranged in axial staggered stacking. The basic cells of adjacent secondary honeycomb networks are preferably arranged in 60-90° rotational staggered arrangement, further preferably 70-80°, and more preferably 75°. The secondary honeycomb network is preferably composed of a plurality of branch ends of basic cells connected to each other, and the center distance between adjacent basic cells is preferably 2-6 mm, further preferably 3-5 mm, and more preferably 4 mm. The basic cell is preferably composed of a radial branch unit.

[0031] In the present application, the basic cell is preferably composed of a main branch extending three-dimensionally radially from the central core, the number of main branches is preferably 3-6, further preferably 4-5, the length of the main branch is preferably 0.8-2 mm, further preferably 1-1.8 mm, and more preferably 1.5 mm, the root diameter of the main branch is preferably 0.2-0.4 mm, further preferably 0.25-0.35 mm, and more preferably 0.3 mm, and the tip diameter of the main branch is preferably 0.02-0.1 mm, further preferably 0.04-0.08 mm, and more preferably 0.06 mm. The main branch is preferably bifurcated into a secondary branch to form a spatial network structure, the number of secondary branches bifurcated from each main branch is preferably 2-3, further preferably 3, and the length of the secondary branch is preferably 0.4-1 mm, further preferably 0.5-0.8 mm, and more preferably 0.6 mm. ​The adjacent secondary honeycomb networks are preferably connected through branch natural cross-linking points, and the equivalent connection length of the branch cross-linking points is preferably 0.4-0.8 mm, further preferably 0.5-0.7 mm, more preferably 0.6 mm.

[0032] In the application, the mass percentage of the skeleton reinforcer is preferably 30-50%, further preferably 35-45%, more preferably 40%, and the rest is preferably the flesh reinforcer.

[0033] The application also provides a preparation method of the lightweight composite metal material, comprising the following steps: 1) designing and establishing a three-dimensional model of a skeleton reinforcer with a dandelion structure or a dandelion honeycomb combined structure through Solidworks modeling software; 2) preparing the skeleton reinforcer through selective laser melting (SLM) 3D printing; 3) performing infiltration treatment on the skeleton reinforcer and the flesh reinforcer to obtain the lightweight composite metal material.

[0034] In the application, the parameters of the selective laser melting 3D printing in step 2) are as follows: the laser power is preferably 200-400 W, further preferably 250-350 W, more preferably 300 W, the scanning speed is preferably 1000-1250 mm / s, further preferably 1050-1200 mm / s, more preferably 1100-1150 mm / s, the scanning interval is preferably 60-100 μm, further preferably 70-90 μm, more preferably 80 μm, the powder laying thickness is preferably 20-30 μm, further preferably 24-26 μm, more preferably 25 μm, the preheating temperature of the substrate is preferably 120-130°C, further preferably 124-126°C, more preferably 125°C, the temperature of the powder tank is preferably 110-115°C, further preferably 112°C, and the printing layer thickness is preferably ≤30 μm, further preferably ≤25 μm.

[0035] In the application, after the printing of the skeleton reinforcer in step 2) is completed, the skeleton reinforcer is preferably stored in an argon atmosphere to avoid oxidation.

[0036] In the application, the skeleton reinforcer and the flesh reinforcer in step 3) are preferably placed in a vacuum infiltration furnace for infiltration treatment, and the vacuum degree of the vacuum infiltration furnace is preferably -0.05 to -0.01 MPa, further preferably -0.04 to -0.02 MPa, more preferably -0.03 MPa.

[0037] In the present application, the infiltration treatment in step 3) is preferably carried out under electromagnetic stirring, the frequency of the electromagnetic stirring is preferably 45-50 Hz, further preferably 46-48 Hz, more preferably 47 Hz, and the current intensity is preferably 100-150 A, further preferably 120-140 A, more preferably 130 A.

[0038] In the present application, the alternating magnetic field generated by the electromagnetic stirring can induce eddy current in the melt, destroy the gas film barrier between the melt and the solid interface, and thus enhance the wettability of the melt to the surface of the solid reinforcement (skeleton reinforcement) or matrix (flesh reinforcement).

[0039] In the present application, the temperature of the infiltration treatment in step 3) is preferably 720-800℃, further preferably 740-780℃, more preferably 760℃, the time of the infiltration treatment is preferably 15-45 min, further preferably 20-40 min, more preferably 30 min, and the heating rate to the infiltration treatment temperature is preferably 20-30℃ / min, further preferably 24-26℃ / min, more preferably 25℃ / min.

[0040] In the present application, the infiltration treatment in step 3) is preferably carried out while filling argon, and the vacuum degree of the vacuum infiltration furnace is adjusted to 0.5-1 MPa, preferably 0.6-0.9 MPa, further preferably 0.8 MPa.

[0041] In the present application, after the infiltration treatment in step 3) is completed, the temperature is preferably lowered to room temperature at a cooling rate of 10-20℃ / min, further preferably 15℃ / min, and then the lightweight composite metal material is taken out.

[0042] The technical solutions provided by the present application will be described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present application. Example 1

[0043] In this embodiment, Ti-6Al-4V titanium alloy is selected as the material of the skeleton reinforcement, the skeleton reinforcement has a dandelion structure, 5-series aluminum alloy 5052 is selected as the material of the flesh reinforcement, the mass percentage of the skeleton reinforcement is 38%, and the rest is the flesh reinforcement, a lightweight titanium-aluminum composite metal material with a dandelion structure is prepared, and the three-dimensional model cell diagram thereof is shown in Figure 1 The three-dimensional model diagram of the skeleton reinforcement is shown in Figure 2 The tensile mechanical property curve diagram of the skeleton reinforcement is shown in Figure 3

[0044] The specific preparation method is as follows: ​1) A 3D structural model of a skeleton reinforcement body with a dandelion-like structure was designed and established using SolidWorks modeling software. The skeleton reinforcement body with the dandelion-like structure was composed of a plurality of layered stacked spatial network structures. The spatial network structure (porosity of 50%) was composed of multi-level branches interconnected with each other. The multi-level branches were multi-level branches extending three-dimensionally from a core node. The multi-level branches had three branch levels. The length of each single-level branch was 0.4 mm. The diameter of the branch decreased radially from the core to the outside. The diameter of the first-level branch was 0.2 mm, and the diameter of the last-level branch was 0.15 mm. The radial spacing between adjacent branches was 0.2 mm. The stacking units of the spatial network structure were periodically arranged in the axial direction, and the center distance between adjacent stacking units was 0.4 mm.

[0045] 2) Spherical Ti-6Al-4V titanium alloy powder with a particle size of 20 μm was 3D printed using selective laser melting (SLM) technology to produce a skeleton reinforcement with a dandelion-like structure. The SLM printing parameters were as follows: laser power of 260 W, scanning speed of 1250 mm / s, scanning spacing of 60 μm, powder thickness of 30 μm, substrate preheating temperature of 120°C, powder chamber temperature of 110°C, and print layer thickness of 30 μm. After printing, the skeleton reinforcement was stored in an argon atmosphere.

[0046] 3) The dandelion-structured titanium alloy skeleton reinforcement and the 5 series aluminum alloy 5052 block were placed in a graphite crucible with a boron nitride coated inner wall, and infiltrated in a vacuum infiltration furnace (vacuum degree of -0.05 MPa). The infiltration treatment temperature was 760°C, the time was 30 min, and the heating rate to the infiltration treatment temperature was 25°C / min. Argon was filled during the infiltration treatment, the vacuum degree of the vacuum infiltration furnace was adjusted to 0.5 MPa, and electromagnetic stirring was applied at the same time (the frequency of the electromagnetic stirring was 48 Hz and the current intensity was 130 A). Then, the temperature was cooled at a cooling rate of 20°C / min until room temperature to obtain a lightweight composite metal material.

[0047] The lightweight composite metal material with the dandelion-like structure prepared in this embodiment has a density of 99.2%, a room temperature tensile yield strength of 565 MPa, and a uniform elongation after fracture of 24%. Example 2

[0048] In this embodiment, Ti-6Al-4V titanium alloy is selected as the material of the skeleton reinforcement, and the skeleton reinforcement is a dandelion honeycomb combination structure. 5 series aluminum alloy 5083 is selected as the material of the flesh reinforcement. The mass percentage of the skeleton reinforcement is 44%, and the rest is the flesh reinforcement. A lightweight titanium-aluminum composite metal material with a dandelion honeycomb combination structure is prepared. The three-dimensional model of the skeleton reinforcement is shown in the figure below. Figure 4 As shown in the figure, the tensile mechanical properties curve of the skeleton reinforcement is as follows Figure 5 A three-dimensional model diagram of the lightweight composite metal material with the dandelion-like honeycomb bonding structure is shown in FIG. 1. Figure 6 An interface micro-morphology diagram of the skeleton reinforcer and the flesh reinforcer is shown in FIG. 2.

[0049] The specific preparation method is as follows: 1) A 3D structure model of the skeleton reinforcer with the dandelion-like honeycomb bonding structure is designed and established by using SolidWorks modeling software. The skeleton reinforcer with the dandelion-like honeycomb bonding structure is a three-stage toughened skeleton, which is composed of a plurality of two-stage honeycomb networks arranged in a staggered stack along the axial direction. The basic cells of adjacent two-stage honeycomb networks are arranged in a 60° rotational staggered manner. The two-stage honeycomb network is composed of the branch ends of a plurality of basic cells connected to each other. The center distance between adjacent basic cells is 4 mm. The basic cell is composed of a radial branch unit. The basic cell is composed of a main branch extending three-dimensionally radially from the center core. The number of main branches is 5. The length of the main branch is 1.5 mm. The root diameter of the main branch is 0.3 mm. The tip diameter of the main branch is 0.08 mm. Two secondary branches branch out from each main branch. The length of the secondary branch is 0.6 mm. Adjacent two-stage honeycomb networks are connected through natural cross-linking points of branches. The equivalent connection length of the branch cross-linking point is 0.4 mm.

[0050] 2) Spherical Ti-6Al-4V titanium alloy powder with a particle size of 37 μm is used to 3D print the skeleton reinforcer with the dandelion-like honeycomb bonding structure by using selective laser melting (SLM) technology. The SLM printing parameters are as follows: the laser power is 240 W, the scanning speed is 1250 mm / s, the scanning interval is 70 μm, the powder laying thickness is 30 μm, the preheating temperature of the substrate is 130 °C, the temperature of the powder tank is 115 °C, the printing layer thickness is 25 μm, and the skeleton reinforcer is stored in an argon atmosphere after printing is completed.

[0051] 3) The dandelion-like honeycomb bonding structure titanium alloy skeleton reinforcer and the 5-series aluminum alloy 5083 block are placed in a graphite crucible coated with boron nitride on the inner wall, and subjected to infiltration treatment in a vacuum infiltration furnace (vacuum degree is -0.03 MPa). The infiltration treatment temperature is 780 °C, the time is 45 min, the heating rate to the infiltration treatment temperature is 25 °C / min, argon is filled during the infiltration treatment, the vacuum degree of the vacuum infiltration furnace is adjusted to 1.0 MPa, and electromagnetic stirring (frequency of electromagnetic stirring is 50 Hz, current intensity is 150 A) is applied. Then, the temperature is decreased at a rate of 15 °C / min until room temperature, to obtain the lightweight composite metal material.

[0052] The density of the lightweight composite metal material with the dandelion-like honeycomb combined structure prepared in the embodiment is 99.7%, the tensile yield strength at room temperature is 652 MPa, and the uniform elongation after fracture is 28%, indicating that the dandelion-like honeycomb combined structure significantly improves the impact toughness and plastic ductility of the composite material through the staggered stacking mechanism, and exhibits excellent mechanical synergistic performance. Example 3

[0053] The embodiment is basically the same as example 1, except that the mass percentage of the skeleton reinforcer is 40%, and the rest is the flesh reinforcer; the structure of the 3D structure model of the skeleton reinforcer of the dandelion-like structure is different, and specifically as follows: the skeleton reinforcer of the dandelion-like structure is composed of a plurality of space network structures stacked in layers, the space network structure (porosity is 40%) is composed of a plurality of levels of branches connected to each other, the plurality of levels of branches are a plurality of levels of branches extending three-dimensionally outward from a core node, the level number of the plurality of levels of branches is 3, the length of each single level of branches is 0.45 mm, the diameter of the branches decreases gradually along the radial direction from the core outward, the diameter of the first level of branches is 0.3 mm, the diameter of the last level of branches is 0.2 mm, the radial distance between adjacent branches is 0.3 mm, and the stacking units of the space network structure are periodically arranged in the axial direction, and the center distance of adjacent stacking units is 0.5 mm.

[0054] The density of the lightweight composite metal material with the dandelion-like structure prepared in the embodiment is 99.4%, the tensile yield strength at room temperature is 572 MPa, and the uniform elongation after fracture is 25%. Example 4

[0055] The embodiment is basically the same as example 1, except that the mass percentage of the skeleton reinforcer is 30%, and the rest is the flesh reinforcer; the structure of the 3D structure model of the skeleton reinforcer of the dandelion-like structure is different, and specifically as follows: the skeleton reinforcer of the dandelion-like structure is composed of a plurality of space network structures stacked in layers, the space network structure (porosity is 70%) is composed of a plurality of levels of branches connected to each other, the plurality of levels of branches are a plurality of levels of branches extending three-dimensionally outward from a core node, the level number of the plurality of levels of branches is 3, the length of each single level of branches is 0.5 mm, the diameter of the branches decreases gradually along the radial direction from the core outward, the diameter of the first level of branches is 0.25 mm, the diameter of the last level of branches is 0.16 mm, the radial distance between adjacent branches is 0.4 mm, the stacking units of the space network structure are periodically arranged in the axial direction, and the center distance of adjacent stacking units is 0.6 mm.

[0056] The density of the lightweight composite metal material with the dandelion-like structure prepared in the embodiment is 99.1%, the tensile yield strength at room temperature is 570 MPa, and the uniform elongation after fracture is 23%. Example 5

[0057] The same as example 1, the difference is that the mass percentage of the skeleton reinforcer is 36%, the rest is the flesh reinforcer; the parameters of 3D printing the skeleton reinforcer with the dandelion structure are different, specifically as follows: the laser power is 200 W, the scanning speed is 1000 mm / s, the scanning interval is 70 μm, the powder laying thickness is 20 μm, the preheating temperature of the substrate is 125 ℃, the temperature of the powder tank is 115 ℃, and the printing layer thickness is 30 μm.

[0058] The density of the lightweight composite metal material with the dandelion structure prepared in the embodiment is 99.3%, the tensile yield strength at room temperature is 573 MPa, and the uniform elongation after fracture is 25%. Example 6

[0059] The same as example 1, the difference is that the parameters of the infiltration treatment of the dandelion structure titanium alloy skeleton reinforcer and the 5 series aluminum alloy 5052 are different, specifically as follows: the temperature of the infiltration treatment is 720 ℃, the time is 45 min, the heating rate for heating to the temperature of the infiltration treatment is 20 ℃ / min, argon is filled during the infiltration treatment, the vacuum degree of the vacuum infiltration furnace is adjusted to 0.8 MPa, and electromagnetic stirring is applied (the frequency of the electromagnetic stirring is 45 Hz, and the current intensity is 100 A).

[0060] The density of the lightweight composite metal material with the dandelion structure prepared in the embodiment is 99.4%, the tensile yield strength at room temperature is 578 MPa, and the uniform elongation after fracture is 24%. Example 7

[0061] The same as example 2, the difference is that the mass percentage of the skeleton reinforcer is 50%, the rest is the flesh reinforcer; the 3D structure model of the skeleton reinforcer of the dandelion honeycomb combined structure is different, specifically as follows: the skeleton reinforcer of the dandelion honeycomb combined structure is a three-level toughening skeleton, the three-level toughening skeleton is composed of a plurality of secondary honeycomb networks which are arranged in a staggered stack along the axial direction, the basic cells of adjacent secondary honeycomb networks are arranged in a 80° rotational staggered manner, the secondary honeycomb network is composed of a plurality of branch ends of basic cells which are connected to each other, the center distance between adjacent basic cells is 2 mm, the basic cell is composed of radial branch units, the basic cell is composed of a main branch which extends three-dimensionally and radially from the center core, the number of the main branch is 3, the length of the main branch is 0.8 mm, the root diameter of the main branch is 0.2 mm, the tip diameter of the main branch is 0.02 mm, 3 secondary branches are bifurcated from each main branch, the length of the secondary branch is 0.4 mm, adjacent secondary honeycomb networks are connected through the natural crosslinking points of the branches, and the equivalent connection length of the crosslinking points of the branches is 0.5 mm. The lightweight composite metal material with the dandelion-like honeycomb structure prepared in this embodiment has a density of 99.4%, a room temperature tensile yield strength of 646 MPa, and a uniform elongation after fracture of 26%. Example 8

[0062] It is basically the same as Example 2, except that: the structure of the 3D structural model of the skeleton reinforcement of the dandelion honeycomb combined structure is different, specifically as follows: the skeleton reinforcement of the dandelion honeycomb combined structure is a three-level toughening skeleton, and the three-level toughening skeleton is composed of a plurality of secondary honeycomb networks stacked and arranged in an axially staggered manner. The basic cells of adjacent secondary honeycomb networks are arranged in a 90° rotational staggered manner. The secondary honeycomb network is composed of the branch ends of a plurality of basic cells connected to each other, and the center spacing between adjacent basic cells is 6 mm. The basic cell is composed of radial branch units, and the basic cell is composed of main branches extending three-dimensionally from the central core to the outside. The number of main branches is 3, the length of the main branch is 2 mm, the root diameter of the main branch is 0.4 mm, and the tip diameter of the main branch is 0.1 mm. Each main branch branches out 3 secondary branches, the length of the secondary branch is 1 mm, and the adjacent secondary honeycomb networks are connected by the natural cross-linking points of the branches, and the equivalent connection length of the branch cross-linking points is 0.8 mm. The lightweight composite metal material with the dandelion-like honeycomb structure prepared in this embodiment has a density of 99.6%, a room temperature tensile yield strength of 654 MPa, and a uniform elongation after fracture of 29%. Example 9

[0063] It is basically the same as Example 2, except that: the parameters of the 3D printing with a dandelion-like honeycomb combined structure skeleton reinforcement by selective laser melting technology are different, specifically as follows: the laser power is 400W, the scanning speed is 1200mm / s, the scanning spacing is 100μm, the powder thickness is 25μm, the preheating temperature of the substrate is 130℃, the temperature of the powder cabin is 110℃, and the printing layer thickness is 20μm.

[0064] The lightweight composite metal material with the dandelion-like honeycomb structure prepared in this embodiment has a density of 99.5%, a room temperature tensile yield strength of 648 MPa, and a uniform elongation after fracture of 27%. Example 10

[0065] The embodiment 2 is basically the same, except that the mass percentage of the skeleton reinforcer is 48%, the rest is the flesh reinforcer; the parameters for infiltrating the skeleton reinforcer of the dandelion-like honeycomb combined structure titanium alloy and the 5-series aluminum alloy 5083 are different, and the parameters are as follows: the temperature for the infiltration treatment is 800℃, the time is 15 min, the temperature rising rate for rising to the infiltration treatment temperature is 30℃ / min, argon is filled during the infiltration treatment, the vacuum degree of the vacuum infiltration furnace is adjusted to 1.0 MPa, and electromagnetic stirring is applied (the frequency of the electromagnetic stirring is 50 Hz, and the current intensity is 150 A).

[0066] The density of the lightweight composite metal material with the dandelion-like honeycomb combined structure prepared in the embodiment is 99.9%, the tensile yield strength at room temperature is 657 MPa, and the even elongation after breaking is 30%.

[0067] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A lightweight composite metal material, characterized in that: The lightweight composite metal material includes a flesh reinforcement body and a skeleton reinforcement body; The skeleton reinforcement body has a bionic structure, and the bionic structure is a dandelion-like structure or a dandelion-like honeycomb-combined structure.

2. The lightweight composite metal material according to claim 1, characterized in that: The material of the skeleton reinforcement is titanium alloy, and the particle size of the titanium alloy is 20-37 μm; The material of the bone and flesh reinforcement is aluminum alloy.

3. The lightweight composite metal material according to claim 1 or 2, characterized in that: When the bionic structure is a dandelion-like structure, the skeleton reinforcement is composed of multiple spatial network structures stacked in layers; The spatial network structure is composed of multiple levels of branches connected to each other; The multi-level branches are multi-level branches that radiate outward in three dimensions from the core node.

4. The lightweight composite metal material according to claim 3, characterized in that: The multi-stage branch has three stages, the length of each single-stage branch is 0.4-0.5 mm, the diameter of the branch decreases radially from the core to the outside, the diameter of the first-stage branch is 0.2-0.3 mm, the diameter of the last-stage branch is 0.15-0.2 mm, and the radial spacing between adjacent branches is 0.2-0.4 mm; The stacking units of the spatial network structure are periodically arranged in the axial direction, and the center distance between adjacent stacking units is 0.4-0.6 mm.

5. The lightweight composite metal material according to claim 4, characterized in that: When the bionic structure is a dandelion honeycomb combined structure, the skeleton reinforcement is a three-level toughening skeleton; The three-level toughening skeleton is composed of a plurality of secondary honeycomb networks stacked and staggered along the axial direction, and the basic cells of adjacent secondary honeycomb networks are arranged in a 60-90° rotational staggered manner; The secondary cellular network is composed of a plurality of basic cells whose branch ends are connected to each other, and the center distance between adjacent basic cells is 2 to 6 mm; The basic cell is composed of radial branch units.

6. The lightweight composite metal material according to claim 5, characterized in that: The basic cell is composed of main branches extending three-dimensionally from the central core, the number of main branches is 3 to 6, the length of the main branches is 0.8 to 2 mm, the root diameter of the main branches is 0.2 to 0.4 mm, and the tip diameter of the main branches is 0.02 to 0.1 mm; The main branch branches out secondary branches to form a spatial network structure, and each main branch branches out The number of secondary branches is 2 to 3, and the length of secondary branches is 0.4 to 1 mm; Adjacent secondary honeycomb networks are connected through natural cross-linking points of branches, and the equivalent connection length of branch cross-linking points is 0.4~0.8mm.

7. The lightweight composite metal material according to claim 1, characterized in that: The mass percentage of the skeleton reinforcement is 30-50%, and the rest is bone and flesh reinforcement.

8. The method for preparing a lightweight composite metal material according to any one of claims 1 to 7, characterized in that: The steps include: 1) Design and establish a three-dimensional model of a skeleton reinforcement body with a dandelion-like structure or a dandelion-like honeycomb combined structure using Solidworks modeling software; 2) Fabrication of skeleton reinforcement by selective laser melting 3D printing; 3) The skeleton reinforcement and the bone-flesh reinforcement are subjected to infiltration treatment to obtain a lightweight composite metal material.

9. The preparation method according to claim 8, characterized in that Step 2) The parameters of the selective laser melting 3D printing are as follows: laser power of 200-400 W, scanning pitch of 60-100 μm, scanning speed of 1000-1250 mm / s, powder thickness of 20-30 μm, substrate preheating temperature of 120-130°C, powder chamber temperature of 110-115°C, and print layer thickness ≤30 μm.

10. The preparation method according to claim 9, characterized in that Step 3) The infiltration treatment is performed under electromagnetic stirring, the frequency of the electromagnetic stirring is 45-50 Hz, and the current intensity is 100-150 A; The infiltration treatment temperature is 720-800° C., the infiltration treatment time is 15-45 minutes, and the heating rate to the infiltration treatment temperature is 20-30° C. / min.

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