Fe / Al layered composite material based on continuous carbon fibers and preparation method of Fe / Al layered composite material

Abstract

The invention relates to the technical field of metal-intermetallic compound layered composite materials, and discloses a Fe / Al layered composite material based on continuous carbon fibers and a preparation method thereof.The preparation method comprises the steps that continuous carbon fiber tows are subjected to alcohol impregnation and then pretreated, and pretreated continuous carbon fiber tows are obtained; carrying out double-plating gradient modification on the pretreated continuous carbon fiber tow; and polishing a stainless steel thin foil, then etching the stainless steel thin foil to obtain a standby stainless steel thin foil, stacking the standby stainless steel thin foil and the modified continuous carbon fiber tow, and placing the stacked stainless steel thin foil and the modified continuous carbon fiber tow in a graphite mold for fixed sintering to obtain the Fe / Al layered composite material based on the continuous carbon fibers. The obtained layered composite material has excellent interface bonding, and interface cracking and obvious defects do not occur between the continuous fibers and the transition layer. Compared with a traditional Fe / Al layered composite material, the overall mechanical performance of the composite material prepared through the preparation technology is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal-intermetallic compound layered composite materials, and in particular to a Fe / Al layered composite material based on continuous carbon fibers and a preparation method thereof. Background Art

[0002] Metal-intermetallic compound layered composites are a novel material that mimics the laminated structure of natural shells. Shells possess a unique "brick-and-mortar" structure (interweaving brittle and ductile layers), which significantly enhances both strength and toughness. First, layered composites utilize deformation and bridging within the metal layers to blunt cracks. The deflection of cracks at the metal-intermetallic compound interface hinders crack propagation, resulting in significant advantages in strength, plasticity, toughness, and impact resistance. Second, the comprehensive mechanical properties of layered composites can be determined by the composition and thickness of the foils, and the type and volume fraction of the resulting phases can be controlled by adjusting the foil stacking pattern and fabrication process. These characteristics make them ideal for achieving engineered microstructures with specific properties. Furthermore, to further enhance the plastic deformation capacity of composites, the introduction of reinforcements into intermetallic compounds is a new avenue for the development of layered composites. Reinforcements vary widely, primarily including continuous long fibers and short fibers. In addition, layered composites are also very suitable for the production of scalable structural materials for commercial and dual-use military and civilian purposes (for example, civilian armor, tank armor, etc.) and aerospace applications that require light weight and high specific performance.

[0003] So far, Ti / Al MIL composites have been widely and deeply studied in the whole MIL composite family. It is the only phase formed by reaction sintering, and the intermetallic compound is a hard and brittle phase, which greatly limits the flexible adjustment of material properties. In order to seek composite materials with excellent comprehensive mechanical properties and save costs, Fe / Al composite materials have gradually been studied in depth. There are as many as five intermetallic compounds in the Fe / Al system, and these five intermetallic compounds can undergo phase transformation in a lower temperature range, which makes the material itself highly designable. Secondly, the preparation cost of the raw material Fe foil is much lower than that of the Ti-Al system Ti foil, which makes the research of Fe / Al composite materials have a very broad application prospect.

[0004] In the field of MIL composite material preparation technology, various techniques have been developed, including rolling lamination, explosive lamination, spark sintering, and vacuum hot pressing. To better meet the demands for material preparation quality and efficiency, rapid hot pressing (FHP) has been introduced as a new material preparation method. Firstly, the raw materials are placed in a high-vacuum heating zone according to a designed composite method, and a high-pressure hydraulic ram provides stable pressure output to ensure uniform microstructure. Secondly, rapid heating maintains a high interdiffusion rate among the elements in the composite material, ultimately achieving a good metallurgical bond.

[0005] Based on this, providing a Fe / Al layered composite material based on continuous carbon fibers prepared by a rapid hot pressing sintering method and a preparation method thereof has important practical significance. Summary of the Invention

[0006] In view of this, the present invention proposes an Fe / Al layered composite material based on continuous carbon fibers and a preparation method thereof, aiming to solve at least one of the above-mentioned background technical problems.

[0007] The present invention provides a method for preparing a Fe / Al layered composite material based on continuous carbon fibers, comprising the following steps: impregnating the continuous carbon fiber tow with alcohol, and then pretreating the tow to obtain a pretreated continuous carbon fiber tow; performing double-layer gradient modification on the pretreated continuous carbon fiber tow to obtain a modified continuous carbon fiber tow; The stainless steel thin foil is polished and then etched to obtain a spare stainless steel thin foil; The spare stainless steel thin foil and the modified continuous carbon fiber tow are stacked, placed in a graphite mold and fixed and sintered to obtain the Fe / Al layered composite material based on continuous carbon fiber.

[0008] Preferably, the parameters of the alcohol impregnation are: placing the continuous carbon fiber tow in ethanol and letting it stand for 30 to 35 minutes; the pretreatment specifically includes: transferring the continuous carbon fiber tow after alcohol impregnation into new anhydrous ethanol for rinsing to remove dissolved oil impurities, and finally draining; the stainless steel foil includes 0.04 mm 1060 aluminum foil, 0.04 mm 430SS foil, and 0.2 mm 304SS foil.

[0009] Preferably, the double-layer gradient modification is specifically as follows: a 50-100 nm Ni-P alloy transition layer is deposited on the surface of the pretreated continuous carbon fiber tow by magnetron sputtering technology, and then a 20-50 nm Ni-P alloy transition layer is coated by a sol-gel method. Nano coating.

[0010] Preferably, the parameters of the magnetron sputtering technology are: vacuum degree is - , working pressure is 0.3Pa-0.5Pa; sputtering power is 280W-320W, atmosphere is Ar gas; The sol-gel method is specifically as follows: aluminum nitrate and citric acid are added to ethanol in sequence, stirred at a speed of 300r / min-400r / min for 3h-4h in a constant temperature water bath at 50°C-60°C to form a transparent and uniform sol, and then allowed to stand and age at room temperature for 24h-36h; an immersion-pulling method is used for coating, and the pretreated continuous carbon fiber tow is immersed in the sol for 30s-40s, and then taken out at a uniform pulling speed of 2mm / s-3mm / s, and dried at room temperature for 10min-15min; then placed in a vacuum drying oven and dried at 80°C-100°C for 2h-3h; wherein the molar ratio of the aluminum nitrate: citric acid: ethanol is 1:1.2:8~1:1.5:10.

[0011] Preferably, the polishing of the stainless steel foil is specifically performed by: polishing the stainless steel foil using a low-temperature plasma bombardment method, the parameters of the low-temperature plasma bombardment method are: power 300~350W, time 2~4min; the atmosphere of the low-temperature plasma bombardment method is Ar gas.

[0012] Preferably, the etching is specifically performed by etching the surface of the stainless steel foil using an ultrasonic-assisted electrochemical etching process to form a nano-scale concave-convex structure.

[0013] Preferably, the ultrasonic assisted electrochemical etching process is specifically as follows: a stainless steel foil is used as the anode, a platinum sheet is used as the cathode, the electrode spacing is controlled at 30mm-40mm; the electrolyte is 0.5mol / L-0.8mol / L solution, the electrolyte temperature is 25℃-30℃; ultrasonic assistance is introduced during the etching process, the ultrasonic power is 250W-300W, the ultrasonic frequency is 40kHz-50kHz; the DC current density applied is After etching is completed, the stainless steel foil is quickly taken out and rinsed with deionized water 3-5 times to remove the residual electrolyte on the surface. It is then placed in anhydrous ethanol for ultrasonic cleaning for 10-15 minutes, and finally dried in a vacuum drying oven at 60-80°C for 1-2 hours.

[0014] Preferably, the stacking is performed with 304SS foil-multi-thin foil micro-unit-304SS foil as a stacking unit, and a single sample contains five of the stacking units, wherein the specific stacking method of the multi-thin foil micro-unit is: Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al.

[0015] Preferably, the sintering includes a first sintering stage and a second sintering stage. The first sintering stage is: rapidly heating to 550°C at a heating rate of 100°C / min, then heating to 600°C-650°C at a heating rate of 50°C / min and keeping warm; the second sintering stage is: heating to 850°C-950°C at a heating rate of 100°C / min and keeping warm.

[0016] The present invention also provides a Fe / Al layered composite material based on continuous carbon fibers, and the Fe / Al layered composite material based on continuous carbon fibers is obtained by the preparation method described in the above technical solution.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) Compared with the traditional sintering process, the Fe / Al composite material prepared by the present invention through the "multi-thin foil and two-stage method" process has a faster reaction speed, a shorter preparation cycle, and a higher yield rate. Secondly, compared with Ti / Al-based layered composite materials, it also has obvious advantages such as low cost and high specific performance.

[0018] (2) Microstructural observation of the Fe / Al layered composite material prepared by the present invention revealed excellent interfacial bonding, and no interfacial cracking or obvious defects were observed between the continuous fibers and the transition layer. The compressive strength reached 3019 MPa and the flexural strength reached 855 MPa perpendicular to the lamination direction, while the compressive strength reached 2090 MPa and the flexural strength reached 687 MPa parallel to the lamination direction. Compared with conventional Fe / Al layered composite materials, the overall mechanical properties of the composite material prepared by this process were significantly superior to those of the former. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings: Figure 1 Schematic diagram of the stacking method of original foil and continuous carbon fiber; Figure 2 This is a SEM image of the microscopic morphology of the reaction interface of the composite material of the present invention; Figure 3 X-ray diffraction pattern of the continuous carbon fiber reinforced Fe / Al layered composite material prepared by the present invention; Figure 4 The present invention is a layered composite material along the vertical / parallel to the lamination direction of the flexural stress - strain curve; Figure 5 It is the quasi-static compressive stress-strain curve of the layered composite material of the present invention along the direction perpendicular to / parallel to the stacking direction. DETAILED DESCRIPTION

[0020] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0021] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated value or intervening value in the stated range is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0022] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0023] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0024] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0025] The present invention provides a method for preparing a Fe / Al layered composite material based on continuous carbon fibers, comprising the following steps: impregnating the continuous carbon fiber tow with alcohol, and then pretreating the tow to obtain a pretreated continuous carbon fiber tow; performing double-layer gradient modification on the pretreated continuous carbon fiber tow to obtain a modified continuous carbon fiber tow; The stainless steel thin foil is polished and then etched to obtain a spare stainless steel thin foil; The stainless steel thin foil and the modified continuous carbon fiber tow are stacked, placed in a graphite mold, and fixed and sintered to obtain the Fe / Al layered composite material based on the continuous carbon fiber.

[0026] impregnating the continuous carbon fiber tow with alcohol, and then pretreating the tow to obtain a pretreated continuous carbon fiber tow; The present invention firstly impregnates the continuous carbon fiber tow with alcohol to efficiently remove oil stains, organic impurities and other components on its surface. Alcohol, as a polar solvent, can quickly strip off such impurities by dissolving them. Combined with the subsequent step of "transferring to new anhydrous ethanol for rinsing", the dissolved impurities can be further removed to avoid their secondary adsorption on the surface of the tow, providing a uniform, impurity-free attachment base for the subsequent "double-layer gradient modification", avoiding impurities-induced defects such as pinholes and shedding in the coating, and ensuring the quality of interface bonding.

[0027] In the present invention, the parameters of the alcohol impregnation are preferably: placing the continuous carbon fiber tow in ethanol and letting it stand for 30 to 35 minutes; the pretreatment is specifically preferably: transferring the continuous carbon fiber tow after alcohol impregnation into new anhydrous ethanol for rinsing to remove dissolved oil impurities, and finally draining; the stainless steel foil preferably includes 0.04 mm 1060 aluminum foil, 0.04 mm 430SS foil, and 0.2 mm 304SS foil.

[0028] performing double-layer gradient modification on the pretreated continuous carbon fiber tow to obtain a modified continuous carbon fiber tow; In the present invention, the double-layer gradient modification is preferably: a 50-100 nm Ni-P alloy transition layer is deposited on the surface of the pretreated continuous carbon fiber tow by magnetron sputtering technology, and then a 20-50 nm Ni-P alloy transition layer is coated by sol-gel method. Nano coating.

[0029] Continuous carbon fibers need to be composited with two matrices at the same time: stainless steel (Fe-based) and aluminum foil (Al-based). However, the interface wettability of carbon fibers with Fe and Al is quite different. Double-layer gradient modification achieves precise matching through "layered adaptation": in the inner Ni-P alloy transition layer (50-100nm), the Ni element is highly compatible with the Fe element of the stainless steel matrix (430SS foil, 304SS foil), and can form a stable metal bond through diffusion welding, thus avoiding the interface peeling problem caused by poor wettability when the carbon fibers are in direct contact with the Fe matrix; the outer layer Nano coating (20-50nm) can form good physical adsorption and chemical bonding with the Al matrix. The chemical stability can avoid direct reaction between Al and carbon fiber, solving the technical pain point that a single coating cannot adapt to both Fe and Al matrix at the same time, and significantly improving the interface bonding strength between carbon fiber and the two metal matrices.

[0030] In addition, the double-layer gradient modification can also inhibit the formation of brittle phases and ensure the toughness of the composite material. In the subsequent sintering process, if the carbon fiber directly contacts the Al matrix, chemical reactions are likely to occur to generate brittle phases. (The brittle phase tends to aggregate at the interface, resulting in a decrease in the fracture toughness of the composite material). Nano coating can act as a physical barrier to block the direct diffusion channel between carbon fiber and Al atoms, thus inhibiting the At the same time, the inner Ni-P alloy transition layer has a certain plasticity, which can buffer the interface stress through slight deformation when subjected to stress, avoiding interface cracking caused by stress concentration, and taking into account the strength and toughness of the composite material.

[0031] During the transfer and stacking process from pretreatment to sintering, the surface of continuous carbon fiber is prone to slight oxidation due to contact with air, or absorbs tiny impurities in the environment, affecting the subsequent bonding effect with the metal matrix. The nano-coating is dense (porosity ≤ 3%) and can form a stable protective layer on the surface of the carbon fiber, isolating it from air and impurities, and preventing secondary contamination or oxidation of the carbon fiber surface. At the same time, the Ni-P alloy transition layer can enhance the carbon fiber's resistance to high-temperature oxidation, providing protection for subsequent high-temperature sintering at 850°C-950°C, preventing the carbon fiber from structural degradation at high temperatures, and ensuring process stability. The magnetron sputtering and sol-gel methods used in the double-layer modification are both low-temperature, low-damage processes: magnetron sputtering is carried out in a vacuum environment, the target temperature is controlled at 40°C-60°C, and the carbon fiber bundles move at a uniform speed to avoid local overheating; after coating, the sol-gel method only requires vacuum drying at 80°C-100°C, and no high-temperature sintering is required. Both processes will not destroy the carbon skeleton structure of the carbon fiber, and can ensure that the tensile strength retention rate of the modified carbon fiber monofilament is ≥95%, avoiding damage to the carbon fiber core reinforcement performance due to the modification process, and providing reliable strength support for the composite material.

[0032] In the present invention, the parameters of the magnetron sputtering technology are preferably: vacuum degree is - , the working pressure is 0.3Pa-0.5Pa; the sputtering power is 280W-320W, the atmosphere is Ar gas; further preferably: the vacuum degree is ~ , the working gas pressure is 0.3Pa-0.4Pa; the sputtering power is 280W-300W, and the atmosphere is Ar gas.

[0033] The sol-gel method is specifically preferably as follows: aluminum nitrate and citric acid are added to ethanol in sequence, stirred at a speed of 300r / min-400r / min for 3h-4h in a constant temperature water bath at 50°C-60°C to form a transparent and uniform sol, and then allowed to stand and age at room temperature for 24h-36h; an immersion-pulling method is used for coating, the pretreated continuous carbon fiber tow is immersed in the sol for 30s-40s, and then taken out at a uniform pulling speed of 2mm / s-3mm / s, and dried at room temperature for 10min-15min; then placed in a vacuum drying oven and dried at 80°C-100°C for 2h-3h; wherein the molar ratio of aluminum nitrate: citric acid: ethanol is 1:1.2:8~1:1.5:10.

[0034] The stainless steel thin foil is polished and then etched to obtain a spare stainless steel thin foil; During production and storage, thin stainless steel foil naturally forms a dense chromium oxide film and absorbs impurities such as oil and dust. These substances can hinder direct bonding with aluminum foil and carbon fibers, resulting in interfacial voids or insufficient bonding strength. The present invention uses low-temperature plasma bombardment to polish thin stainless steel foil. The physical bombardment of high-energy plasma particles rapidly strips away the surface oxide film and loose impurities, and the Ar atmosphere prevents secondary oxidation of the stainless steel foil during polishing. Compared to traditional polishing with a scouring pad, this method leaves no mechanical friction residue and does not physically scratch or deform ultra-thin stainless steel foil (such as 0.04mm 430SS foil), thus ensuring the integrity of the foil. Subsequent ultrasonic-assisted electrochemical etching further removes residual oxide film fragments and tiny impurities. Electrochemical action dissolves stubborn surface oxide layers, while ultrasonic cavitation accelerates impurity desorption, ultimately leaving the stainless steel foil surface clean and free of oxidation and impurities. This provides a clean substrate for subsequent diffusion welding with the aluminum foil and interfacial bonding with the carbon fibers.

[0035] In addition, the synergistic effect of the two treatment processes can construct a controllable nano-scale rough structure on the surface of the stainless steel foil: Ultrasonic-assisted electrochemical etching can accurately form a nano-scale concave-convex structure with an Ra of 50nm~100nm on the surface of the stainless steel foil, greatly increasing the surface specific area. This micro-rough structure can form a "mechanical bite" effect with the adjacent Al foil during the sintering process - Al atoms are more likely to fill the pits on the surface of the stainless steel foil, forming an anchoring structure to avoid interlayer sliding; at the same time, it can also enhance the surface of the modified carbon fiber (containing The physical adsorption area of ​​the nanocoating (likely a nanostructured coating) is increased, reducing interfacial voids and increasing interlayer bonding strength by over 30% (compared to an unetched smooth surface). Low-temperature plasma bombardment provides a preliminary surface roughening, creating a uniform initial surface condition for subsequent electrochemical etching to create a "nano-concave-convex structure." This prevents uneven etching due to variations in initial surface flatness and ensures consistent batch processing. Furthermore, while removing impurities, low-temperature plasma bombardment also introduces active groups (such as hydroxyl and carboxyl groups) onto the stainless steel foil surface, placing surface atoms in a highly excited state. Subsequent electrochemical etching further exposes active Fe and Cr atoms within the stainless steel foil. These activated surface states significantly increase the diffusion reaction rate between the stainless steel foil and the Al foil during sintering. During the first sintering stage (550°C–650°C), Al atoms more readily form stable intermetallic compounds with Fe and Cr atoms on the stainless steel surface, rather than simply physically bonding. This upgrades the interfacial bonding from "physical bonding" to a dual bonding mode of "chemical bonding + physical interlocking," significantly improving interlayer debonding resistance.

[0036] In the present invention, the polishing of the stainless steel foil is preferably performed by: polishing the stainless steel foil by a low-temperature plasma bombardment method, and the parameters of the low-temperature plasma bombardment method are preferably: power 300~350W, time 2~4min; further preferably: power 300W, time 2min; the atmosphere of the low-temperature plasma bombardment method is Ar gas.

[0037] In the present invention, the etching is preferably performed by etching the surface of the stainless steel foil using an ultrasonic-assisted electrochemical etching process to form a nano-scale concave-convex structure.

[0038] In the present invention, the ultrasonic assisted electrochemical etching process is preferably: a stainless steel foil is used as the anode, a platinum sheet is used as the cathode, the electrode spacing is controlled at 30mm-40mm; the electrolyte is 0.5mol / L-0.8mol / L solution, the electrolyte temperature is 25℃-30℃; ultrasonic assistance is introduced during the etching process, the ultrasonic power is 250W-300W, the ultrasonic frequency is 40kHz-50kHz; the DC current density applied is After etching is completed, the stainless steel foil is quickly taken out and rinsed with deionized water 3-5 times to remove the residual electrolyte on the surface. It is then placed in anhydrous ethanol for ultrasonic cleaning for 10-15 minutes, and finally dried in a vacuum drying oven at 60-80°C for 1-2 hours.

[0039] The stainless steel thin foil and the modified continuous carbon fiber tow are stacked, placed in a graphite mold, and fixed and sintered to obtain the Fe / Al layered composite material based on the continuous carbon fiber.

[0040] The present invention uses a specific method to stack stainless steel foil and modified continuous carbon fiber tows before sintering to create a "strong-tough-reinforced" multi-layer synergistic structure, breaking through the performance bottleneck of a single material. The outer layer of 304SS foil provides overall structural support and corrosion protection. 304SS (0.2mm thick) serves as the "outer frame" of the stacked unit and has excellent mechanical strength and corrosion resistance. Compared with the 0.04mm thick 430SS foil, the thicker 304SS foil provides rigid support for the entire composite material, preventing the stack from deforming due to pressure during the sintering process, while also protecting the material from external impact, wear and other mechanical effects during its service life. 304SS contains 18%-20% Cr and 8%-10.5% Ni, and easily forms a dense chromium oxide passivation film on its surface. This film serves as an "anti-corrosion barrier" for the composite material, reducing the contact between the easily oxidized Al foil and external corrosive media, and improving the overall environmental stability of the material (for example, the corrosion rate in a neutral salt spray test is reduced by more than 40%).

[0041] The multi-thin foil micro-units achieve the precise adaptation of "metal toughness + fiber reinforcement". The multi-thin foil micro-units are repeatedly stacked as "Al-carbon fiber-430SS foil" (a total of 7 layers of Al, 6 layers of carbon fiber, and 6 layers of 430SS), forming an alternating structure of "flexibility-reinforcement-rigidity": Al foil (0.04mm 1060 aluminum foil): As a flexible transition layer, it has good plasticity and low density. It can buffer stress by deformation when subjected to force, avoiding brittle fracture of the material caused by stress concentration; at the same time, Al and 430SS can form Fe-Al intermetallic compounds (such as FeAl, ), combining the rigidity of 430SS with the toughness of Al to balance the strength and plasticity of the material; continuous carbon fiber is used as the core reinforcement and is evenly distributed between Al and 430SS along the stacking direction. Its high strength (tensile strength ≥ 3000MPa) and high modulus properties can significantly improve the overall load-bearing capacity of the composite material and solve the problem of "insufficient strength" of traditional Fe / Al layered materials; and carbon fiber and double coating ( ) to ensure its close bonding with the metal matrix and avoid fiber debonding failure; 430SS foil (0.04mm) acts as a rigid spacer to limit excessive flow of Al foil during high-temperature sintering and maintain the integrity of the micro-unit structure; at the same time, 430SS (ferritic stainless steel) has good compatibility with Fe-Al intermetallic compounds, which can further strengthen the interface bonding and avoid interlayer delamination.

[0042] In the present invention, the stacking is performed with 304SS foil-multi-thin foil micro-unit-304SS foil as one stacking unit, and a single sample contains five of the stacking units, wherein the specific stacking method of the multi-thin foil micro-unit is: Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al.

[0043] In the present invention, the sintering includes a first sintering stage and a second sintering stage. The first sintering stage is: rapidly heating to 550°C at a heating rate of 100°C / min, then heating to 600°C-650°C at a heating rate of 50°C / min and keeping warm; the second sintering stage is: heating to 850°C-950°C at a heating rate of 100°C / min and keeping warm.

[0044] The present invention does not impose any special restrictions on the holding time after the first sintering stage and the second sintering stage, and the total sintering time can be controlled within 4 hours.

[0045] The present invention also provides a Fe / Al layered composite material based on continuous carbon fibers, and the Fe / Al layered composite material based on continuous carbon fibers is obtained by the preparation method described in the above technical solution.

[0046] Example 1 (1) Raw material preparation Continuous carbon fiber tow: T700 grade 12K continuous carbon fiber tow (single fiber diameter 7μm, tensile strength 3430MPa) is selected; Metal foil: 0.2mm thick 304SS foil (composition: Cr 18.5%, Ni 9.5%, Fe balance, purity ≥99.9%), 0.04mm thick 430SS foil (composition: Cr 17%, Fe balance, purity ≥99.9%), 0.04mm thick 1060 aluminum foil (Al content ≥99.6%); Chemical reagents: anhydrous ethanol (purity ≥99.7%), aluminum nitrate (Al(NO3)3・9H2O, purity ≥99%), citric acid ( , purity ≥99.5%), concentrated sulfuric acid (concentration 98%), and deionized water.

[0047] (2) Pretreatment and double-coating modification of continuous carbon fiber tow The T700 continuous carbon fiber tow was completely immersed in anhydrous ethanol at room temperature (25°C) for 32 minutes; then it was transferred to new anhydrous ethanol and rinsed for 10 minutes to remove the dissolved oil and reagent residues; finally, the tow was hung and drained for 10 minutes, and the moisture content was controlled to ≤5% to obtain the pretreated continuous carbon fiber tow.

[0048] Double-layer gradient modification: Magnetron sputtering Ni-P alloy transition layer: DC magnetron sputtering equipment is used, the target material is Ni-P alloy target (Ni 89%, P11%, purity ≥99.95%), the target-substrate distance is 90mm; the vacuum chamber is evacuated to , introduce Ar gas with a purity of ≥99.999%, maintain the working gas pressure at 0.4Pa; set the sputtering power to 300W, control the continuous carbon fiber tow to move at a constant speed of 6mm / min, sputter for 14min, and deposit an 80nm thick Ni-P alloy transition layer on the surface of the tow.

[0049] Sol-gel coating Nano coating: A sol was prepared in a molar ratio of aluminum nitrate: citric acid: ethanol = 1:1.3:9. Aluminum nitrate and citric acid were added to ethanol in sequence, and stirred at 350 r / min for 3.5 h in a constant temperature water bath at 55 ° C to form a transparent sol; after aging at room temperature for 30 h, the sol was coated by the dip-pull method: the carbon fiber tow coated with Ni-P layer was immersed in the sol for 35 s, taken out at a uniform speed of 2.5 mm / s, and dried at room temperature for 12 min; then placed in a vacuum drying oven and dried at 85 ° C for 2.5 h to form a 35 nm thick nanocoating on the surface of the tow. Nano-coating was performed to obtain modified continuous carbon fiber tow (coating porosity ≤ 2.5%).

[0050] (3) Polishing and etching of stainless steel foil Low temperature plasma bombardment polishing: 0.2mm 304SS foil and 0.04mm 430SS foil were treated respectively: low-temperature plasma equipment was used, Ar gas atmosphere (flow rate 200mL / min), set power to 320W, bombardment time 3min, to remove the oxide film and loose impurities on the foil surface and avoid mechanical scratches.

[0051] Ultrasonic assisted electrochemical etching: Construct a two-electrode system: a polished stainless steel foil is used as the anode, a platinum sheet (purity ≥ 99.9%) is used as the cathode, and the electrode spacing is 35 mm. Electrolyte preparation: Mix 98% concentrated sulfuric acid with deionized water to prepare 0.6 mol / L solution, maintaining the electrolyte temperature at 28°C; Etching parameters: ultrasonic power 280W, frequency 45kHz, applied DC current density ; Among them, 0.04mm430SS foil etching time is 3.5min, 0.2mm 304SS foil etching time is 5.5min; Post-processing: After etching, rinse with deionized water 4 times (30 seconds each time), ultrasonically clean with anhydrous ethanol for 12 minutes, and finally dry in a vacuum drying oven at 70°C for 1.5 hours to obtain a spare stainless steel foil with a surface Ra of 75nm nano-concave-convex structure.

[0052] (4) Stacking and sintering Stacking assembly: A single sample contained five stacking units consisting of "304SS foil-multi-thin foil micro-unit-304SS foil." The "multi-thin foil micro-unit" was stacked six times in the order of "Al foil-modified carbon fiber tow-430SS foil" (i.e., Al-carbon fiber-430SS-Al-carbon fiber-430SS-…-Al, for a total of seven layers of Al foil, six layers of carbon fiber, and six layers of 430SS foil). During the stacking process, the layers were aligned without misalignment or wrinkles.

[0053] Rapid hot pressing sintering: Place the stack into a graphite mold and fix it in a rapid hot pressing sintering furnace: The first sintering stage: heating to 550°C at a rate of 100°C / min, then to 620°C at a rate of 50°C / min, and holding for 1.2h, during which a pressure of 6MPa was applied; Second sintering stage: heating to 900℃ at a rate of 100℃ / min and holding for 1.2h, during which the pressure was increased to 16MPa; After sintering, the furnace was cooled to room temperature to obtain a Fe / Al layered composite material based on continuous carbon fibers (size: 100 mm × 100 mm × 5 mm).

[0054] Performance and testing like Figure 1 This is a schematic diagram of the specific actual stacking structure of multiple thin foils used in the present invention. This stacking method and foil material selection can ensure that the foils and continuous carbon fibers are stacked on each other and quickly sintered and bonded, greatly shortening the material preparation cycle and greatly improving the yield and mechanical properties, providing an ideal design concept for its widespread application.

[0055] 1. The microstructure and morphology of the Fe / Al layered composite material based on continuous carbon fibers prepared in Example 1 of the present invention were observed by SEM. Scanning was performed at a secondary electron (SE) and a test voltage of 20 KeV, and EDS surface scanning of a typical area was performed to determine the elemental composition of Example 1 of the present invention. The results are as follows Figure 2 As shown in the figure, the experimental data show that the interface between the fiber and the sintered matrix is ​​well bonded. From the EDS data, it can be found that a new compound containing C / Al is formed around the continuous carbon fiber filaments. The specific phase composition shows that the continuous carbon fiber has successfully formed a chemical bond with the substrate and the corresponding transition layer rather than a simple mechanical assembly. This bonding method can ensure that the material has excellent strength and hardness during use and avoid premature failure of the material.

[0056] 2. XRD phase analysis of the Fe / Al layered composite material based on continuous carbon fibers prepared in Example 1 of the present invention was performed. To determine the phases of the final metal layer, transition layer, and newly formed fiber-matrix bond, phase analysis was performed using a Bruker D8 Advance XRD scanner. The scan range was 20-90° at a scan speed of 5° / min. The composition of the specific phase was determined based on the position of the corresponding diffraction peaks.

[0057] The results are as follows Figure 3As shown in the figure, the corresponding data results show that: the matrix product and transition layer phases exist in the (110) and (211) crystal phases respectively, and the reaction product phase of continuous fiber filaments and matrix appears in the two crystal phase families (012) and (014), that is, the new phase: Al4C3 phase.

[0058] 3. The mechanical properties of the Fe / Al layered composite material based on continuous carbon fibers prepared in Example 1 of the present invention were tested using a universal testing machine. In order to verify the mechanical properties and stability of the material in Example 1, three-point bending flexural tests and compressive strength tests were carried out. The MTS Test Works universal testing machine was used to conduct the test. Three groups of parallel samples were tested in two directions, perpendicular to the layer and parallel to the layer, for the two flexural and compressive tests. Among them, the three-point bending test was conducted at a displacement rate of 0.05 mm / Min, and the compressive test was conducted at a displacement rate of 0.5 mm / Min. The results are as follows: Figure 4-5 As shown in the data, the composite material produced by this process exhibits excellent metallurgical bonding at all interfaces and exhibits excellent compressive and flexural strength. In the direction perpendicular to the stacking, the compressive strength reaches 3019 MPa and the flexural strength reaches 855 MPa. Parallel to the stacking, the compressive strength reaches 2090 MPa and the flexural strength reaches 687 MPa. The failure mechanism of this material is the synergistic effect of microcrack initiation and continuous carbon fiber drawing and bridging, ultimately resulting in the composite material's excellent overall mechanical properties.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a Fe / Al layered composite material based on continuous carbon fiber, characterized in that: The following steps are involved: impregnating the continuous carbon fiber tow with alcohol, and then pretreating the tow to obtain a pretreated continuous carbon fiber tow; performing double-layer gradient modification on the pretreated continuous carbon fiber tow to obtain a modified continuous carbon fiber tow; The stainless steel thin foil is polished and then etched to obtain a spare stainless steel thin foil; The spare stainless steel thin foil and the modified continuous carbon fiber tow are stacked, placed in a graphite mold and fixed and sintered to obtain the Fe / Al layered composite material based on continuous carbon fiber.

2. The method for preparing the Fe / Al layered composite material based on continuous carbon fiber according to claim 1, characterized in that: The parameters of the alcohol impregnation are as follows: placing the continuous carbon fiber tow in ethanol and letting it stand for 30 to 35 minutes; the pretreatment specifically includes transferring the alcohol-impregnated continuous carbon fiber tow into new anhydrous ethanol for rinsing to remove dissolved oil impurities, and finally draining; the stainless steel foil includes 0.04 mm 1060 aluminum foil, 0.04 mm 430SS foil, and 0.2 mm 304SS foil.

3. The method for preparing the Fe / Al layered composite material based on continuous carbon fiber according to claim 1, characterized in that: The double-layer gradient modification is specifically as follows: a 50-100 nm Ni-P alloy transition layer is deposited on the surface of the pretreated continuous carbon fiber tow by magnetron sputtering technology, and then a 20-50 nm Ni-P alloy transition layer is coated on the surface of the pretreated continuous carbon fiber tow by a sol-gel method. Nano coating.

4. The method for preparing the Fe / Al layered composite material based on continuous carbon fiber according to claim 3, characterized in that: The parameters of the magnetron sputtering technology are: vacuum degree is ~ , working pressure is 0.3Pa-0.5Pa; sputtering power is 280W-320W, atmosphere is Ar gas; The sol-gel method is specifically as follows: aluminum nitrate and citric acid are added to ethanol in sequence, stirred at a speed of 300r / min-400r / min for 3h-4h in a constant temperature water bath at 50°C-60°C to form a transparent and uniform sol, and then allowed to stand and age at room temperature for 24h-36h; an immersion-pulling method is used for coating, and the pretreated continuous carbon fiber tow is immersed in the sol for 30s-40s, and then taken out at a uniform pulling speed of 2mm / s-3mm / s, and dried at room temperature for 10min-15min; then placed in a vacuum drying oven and dried at 80°C-100°C for 2h-3h; wherein the molar ratio of the aluminum nitrate: citric acid: ethanol is 1:1.2:8~1:1.5:

10.

5. The method for preparing the Fe / Al layered composite material based on continuous carbon fiber according to claim 1, characterized in that: The polishing of the stainless steel foil is specifically performed by using a low-temperature plasma bombardment method to polish the stainless steel foil. The parameters of the low-temperature plasma bombardment method are: power 300-350W, time 2-4 minutes; the atmosphere of the low-temperature plasma bombardment method is Ar gas.

6. The method for preparing the Fe / Al layered composite material based on continuous carbon fiber according to claim 1, characterized in that: The etching specifically includes: etching on the surface of the stainless steel foil using an ultrasonic-assisted electrochemical etching process to form a nano-scale concave-convex structure.

7. The method for preparing the Fe / Al layered composite material based on continuous carbon fibers according to claim 6, characterized in that: The ultrasonic-assisted electrochemical etching process is specifically as follows: a stainless steel foil is used as the anode, a platinum sheet is used as the cathode, and the electrode spacing is controlled at 30mm-40mm; The electrolyte is 0.5mol / L-0.8mol / L solution, the electrolyte temperature is 25℃-30℃; ultrasonic assistance is introduced during the etching process, the ultrasonic power is 250W-300W, the ultrasonic frequency is 40kHz-50kHz; the DC current density applied is After etching is completed, the stainless steel foil is quickly taken out and rinsed with deionized water 3-5 times to remove the residual electrolyte on the surface. It is then placed in anhydrous ethanol for ultrasonic cleaning for 10-15 minutes, and finally dried in a vacuum drying oven at 60-80°C for 1-2 hours.

8. The method for preparing a Fe / Al layered composite material based on continuous carbon fibers according to claim 1, wherein: The stacking is performed with 304SS foil-multi-thin foil micro-unit-304SS foil as a stacking unit, and a single sample contains five of the stacking units. The specific stacking method of the multi-thin foil micro-unit is: Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al-carbon fiber-430SS foil-Al.

9. The method for preparing the Fe / Al layered composite material based on continuous carbon fibers according to claim 1, characterized in that: The sintering includes a first sintering stage and a second sintering stage. The first sintering stage is: rapidly heating to 550°C at a heating rate of 100°C / min, then heating to 600°C-650°C at a heating rate of 50°C / min and keeping warm; the second sintering stage is: heating to 850°C-950°C at a heating rate of 100°C / min and keeping warm.

10. A Fe / Al layered composite material based on continuous carbon fibers, characterized in that: The Fe / Al layered composite material based on continuous carbon fibers is obtained by the preparation method according to any one of claims 1 to 9.

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