Bionic micro-nano layered Nb / Nb5Si3 composite material and preparation method thereof

Abstract

The present application relates to a kind of bionic micro-nano layered Nb / Nb5Si3 Composite material and its preparation method.The bionic micro-nano layered Nb / Nb5Si3 Composite material includes Nb5Si3 Phase and lamellar Nb phase, wherein lamellar Nb phase is significantly parallel staggered arrangement, Nb phase layer thickness is 10~800nm, interval is 50~800nm.The preparation method of the composite material includes the following steps: a certain amount of raw material Nb powder is ball milled into Nb sheet under vacuum condition, then Nb sheet is vacuum dried, and small particle size nanometer Nb sheet is screened out;Raw material Si powder and screened small particle size nanometer Nb sheet are weighed according to proportion, ball milled together, uniformly mixed, vacuum dried to obtain composite powder;After the composite powder is loaded into graphite mold, the composite powder in graphite mold is treated by ultrasonic vibration or metal microsheet rapid directional paving, and composite powder with certain arrangement direction is obtained;The composite powder is together with graphite mold and is carried out vacuum discharge plasma sintering, and bionic micro-nano layered Nb / Nb5Si3 Composite material is prepared.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composite materials and their preparation technology, specifically relating to a biomimetic micro / nano layered Nb / Nb5Si3 composite material and its preparation method. Background Technology

[0002] The Nb / Nb5Si3 composite material has a high melting point (2520℃), a high service temperature (>1600℃), and a low density (7.16 g / cm³). 3 With its high stiffness, high strength, and good oxidation resistance, Nb / Nb5Si3 is considered a key high-temperature structural material for future applications in aero-engines, replacing current nickel-based superalloys, and has significant application prospects. Methods for preparing Nb / Nb5Si3 composite materials mainly include casting, vacuum arc remelting, electron beam melting, and powder metallurgy. Among these, vacuum arc remelting is a commonly used method for preparing Nb / Nb5Si3 composite materials, and this method has played a positive role in promoting the development and application of Nb / Nb5Si3 composite materials. However, this method requires long-term high-temperature heat treatment of the material, resulting in a long preparation cycle, high energy consumption, and complex procedures.

[0003] Currently, the Nb / Nb5Si3 composite materials prepared using the above methods exhibit poor toughness and cold / hot working ability at room temperature, thus hindering their application in high-temperature structural materials. Although the toughness of this Nb / Nb5Si3 composite material can be improved to 10 MPa·m using in-situ composite preparation methods... 1 / 2 The above are not sufficient to meet the requirements for high-temperature structural materials in aero engines, which is a key factor hindering their application in aero engines.

[0004] The micro- and nano-layered structures in biomaterials, with typical layer thicknesses at the submicron or even nanoscale, exhibit a uniform, parallel arrangement of brittle and ductile phases, resulting in both high strength and toughness. This overcomes the strength-toughness inversion bottleneck inherent in traditional metallic and synthetic composite materials, providing excellent inspiration for designing and controlling the comprehensive performance of metallic structural materials. The microstructure of Nb / Nb5Si3 composites consists of brittle Nb5Si3 and ductile Nb phases, providing ideal conditions for preparing biomimetic micro- and nano-layered Nb / Nb5Si3 composites. Therefore, a novel method is proposed to comprehensively improve the strength and toughness of Nb / Nb5Si3 composites by constructing biomimetic micro- and nano-layered structures, promoting their application in aero-engines. Currently, there are very few existing methods for preparing Nb / Nb5Si3 composites with lamellar structures. The main methods are directional solidification and physical vapor deposition. However, the thickness of the Nb phase lamellars in the Nb / Nb5Si3 composites prepared by the above methods is still at the micrometer level, and it is difficult to obtain a micro-nano layered structure. The room temperature fracture toughness of the composites prepared is still insufficient. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, the present invention aims to provide a biomimetic micro / nano layered Nb / Nb5Si3 composite material and its preparation method. The invention utilizes the construction of a biomimetic micro / nano layered structure to comprehensively optimize the Nb / Nb5Si3 composite material, thereby solving the problem of low room temperature toughness of the Nb / Nb5Si3 alloy.

[0006] The technical problem solved by the present invention is achieved by the following technical solution: a biomimetic micro-nano layered Nb / Nb5Si3 composite material, wherein the biomimetic micro-nano layered Nb / Nb5Si3 composite material includes an Nb5Si3 phase and a lamellar Nb phase, wherein the lamellar Nb phase is arranged in parallel and interlaced with each other.

[0007] Specifically, the thickness of the lamellar Nb phase is 10~800nm, and the spacing between the lamellar Nb phases is 50~800nm.

[0008] Specifically, the biomimetic micro / nano layered Nb / Nb5Si3 composite material is made of Nb and Si in an atomic ratio of 1:13~25.

[0009] The biomimetic micro / nano layered Nb / Nb5Si3 composite material is prepared by the following method: raw material Si powder and small-diameter nano Nb flakes are mixed evenly and dried to obtain composite powder; the composite powder is subjected to ultrasonic vibration or rapid orientation and planarization of metal microflakes to obtain composite powder with a certain alignment direction; the composite powder with a certain alignment direction is subjected to vacuum discharge plasma sintering to prepare the biomimetic micro / nano layered Nb / Nb5Si3 composite material.

[0010] The small-particle-size Nb nanosheets have a diameter of 10~30μm and a thickness of 100~800nm.

[0011] The small-particle-size nano-Nb flakes are obtained by wet ball milling and drying of Nb powder.

[0012] The atomic ratio of raw material Si powder to small-particle-size nano Nb sheets is 13~25:1.

[0013] The duration of the ultrasonic vibration is 1-2 days, and the ultrasonic vibration power is 800-2500W.

[0014] The method for rapid orientation and flattening of metal micro-flakes involves applying voltage and magnetic field while ultrasonically vibrating the composite powder. The ultrasonic vibration time is 30-240 min, the ultrasonic vibration power is 800-2500 W, the applied voltage is 3-50 V, and the applied magnetic field is 0.2-0.5 T.

[0015] This invention also provides a method for preparing biomimetic micro / nano layered Nb / Nb5Si3 composite materials, the method comprising the following steps:

[0016] Step 1: Ball mill the raw material Nb powder into Nb flakes under vacuum conditions and then vacuum dry it, and then screen out small-diameter nano Nb flakes; weigh the raw material Si powder and the screened small-diameter nano Nb flakes according to the ratio, ball mill and mix them evenly, and then vacuum dry to obtain composite powder;

[0017] Step 2: The composite powder prepared in Step 1 is loaded into a graphite mold, and the composite powder in the graphite mold is subjected to ultrasonic vibration or rapid orientation and flattening of metal micro-sheets to obtain a composite powder with a certain alignment direction.

[0018] Step 3: The composite powder with a certain alignment direction prepared in Step 2, together with the graphite mold, is subjected to vacuum discharge plasma sintering to prepare the biomimetic micro-nano layered Nb / Nb5Si3 composite material.

[0019] Preferably, in step one, the ball milling method used for the raw material Nb powder is wet ball milling with alcohol as a dispersant, the ball-to-material mass ratio is 10:1, the ball milling speed is 400 r / min, the ball milling time is 2 hours, and the ball milling process is carried out under argon protection.

[0020] Preferably, in step one, when ball milling the raw material Nb powder, the ball milling jar needs to be subjected to a "vacuuming-argon filling" operation and repeated multiple times to ensure that the air inside the ball milling jar is discharged to achieve the vacuum condition.

[0021] Specifically, the small-particle-size Nb nanosheets screened in step one have a diameter of 10~30μm and a thickness of 100~800nm.

[0022] Preferably, in step one, the ball milling method used for the raw material Si powder and the screened small-particle-size nano Nb flakes is wet ball milling with alcohol as a dispersant, the ball-to-material mass ratio is 10:1, the ball milling speed is 250 r / min, the ball milling time is 4 hours, and the ball milling process is carried out under argon protection.

[0023] Preferably, the vacuum drying temperature in step one is 95°C and the vacuum drying time is 3 hours.

[0024] Specifically, in step two, the ultrasonic vibration time is 1-2 days and the ultrasonic vibration power is 800-2500W.

[0025] Specifically, the method for rapid orientation and flattening of metal micro-sheets in step two includes applying voltage and magnetic field while ultrasonically vibrating the composite powder, wherein the ultrasonic vibration time is 30~240min, the ultrasonic vibration power is 800~2500W, the applied voltage is 3~50V, and the applied magnetic field is 0.2~0.5T.

[0026] Specifically, in step three, the sintering vacuum degree is -0.09 to -0.1 MPa, the sintering pressure is 50 MPa, the sintering holding time is 30 to 40 minutes, and the sintering temperature is 1500 to 1600℃.

[0027] By adopting the above technical solution, the biomimetic micro / nano layered Nb / Nb5Si3 composite material provided by the present invention has the following beneficial effects:

[0028] Currently, alloying is the main method used to optimize the toughness of Nb / Nb5Si3. Research results show that alloying has a limited effect on improving toughness; its toughness still cannot meet the application requirements and is significantly lower than that of the target material, nickel-based superalloys. Furthermore, some alloying elements, while improving room-temperature toughness, can reduce the strength or oxidation resistance of the composite material. Compared to Nb / Nb5Si3 prepared by traditional alloying, this invention uses a biomimetic micro / nano layered structure to comprehensively optimize the Nb / Nb5Si3 composite material, achieving a room-temperature fracture toughness of nearly 35 MPa·m. 1 / 2 At the same time, its room temperature strength is maintained above 2300MPa, achieving both strong and tough mechanical properties.

[0029] Secondly, in the preparation method of the biomimetic micro / nano layered Nb / Nb5Si3 composite material provided by this invention, the composite powder undergoes rapid orientation and planarization of metal micro-flakes. Under the action of an electromagnetic field, small-diameter Nb flakes with a diameter of 15-30 μm and a thickness at the nanometer level generate an Ampere force through current. Under the action of ultrasonic vibration and the downward component of the generated Ampere force, the small-diameter Nb flakes rapidly exhibit directional alignment, achieving a planarization effect of thinner, larger, and more regular small-diameter Nb flakes in a very short time. The resulting parallel and interlaced distribution of two-dimensional layered Nb flakes is beneficial for the uniform dissipation or dispersion of energy load, reducing stress concentration, promoting deformation delocalization, and preventing crack initiation and propagation, thereby improving the strength and toughness of the Nb / Nb5Si3 composite material. In addition, the micro / nano layered structure in the Nb / Nb5Si3 composite material has a large number of tortuous interfaces. This important feature can significantly consume interfacial slip energy and crack propagation failure energy, thereby comprehensively improving the strength and toughness of the Nb / Nb5Si3 composite material. Attached Figure Description

[0030] Appendix Figure 1 This is a cross-sectional microstructure diagram of the biomimetic micro / nano layered Nb / Nb5Si3 composite material in Example 1 of the present invention.

[0031] Appendix Figure 2 This is a cross-sectional microstructure diagram of the biomimetic micro / nano layered Nb / Nb5Si3 composite material in Example 2 of the present invention.

[0032] Appendix Figure 3 This is a cross-sectional microstructure diagram of the biomimetic micro / nano layered Nb / Nb5Si3 composite material in Example 3 of the present invention. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0034] This invention provides a biomimetic micro / nano layered Nb / Nb5Si3 composite material, comprising an Nb5Si3 phase and a lamellar Nb phase, wherein the lamellar Nb phases are arranged in parallel and interlaced patterns, and the microstructure exhibits lamellar Nb phases with a thickness of 10-800 nm and a spacing of 50-800 nm between the lamellar Nb phases. This biomimetic micro / nano layered Nb / Nb5Si3 composite material is made from elemental Si and elemental Nb with an atomic ratio of 13-25:1, and the preparation process includes the following steps:

[0035] Step 1: A certain amount of raw material Nb powder, steel balls, and alcohol are loaded into a ball mill jar. The ball mill jar is subjected to a "vacuum-argon filling" operation, which is repeated several times to ensure that the air inside the ball mill jar is discharged. The ball-to-material mass ratio is 10:1, the ball milling speed is 400 r / min, and the ball milling time is 2 hours to ball mill the Nb powder into Nb flakes. The prepared Nb flakes are first vacuum dried and then sieved to screen out small-diameter nano-Nb flakes with a diameter of 10~30μm. The screened small-diameter nano-Nb flakes and raw material Si powder are loaded into a ball mill jar at an atomic ratio of 1:13~25, and a certain amount of alcohol is added. The ball-to-material mass ratio is 10:1, the ball milling speed is 250 r / min, and the ball milling time is 4 hours. After ball milling and mixing evenly under argon protection, vacuum drying is performed at a drying temperature of 95℃ for 3 hours to obtain composite powder.

[0036] Step 2: The dried composite powder prepared in Step 1 is loaded into a graphite mold. To make the randomly arranged Nb sheets in the graphite mold directionally aligned, the composite powder in the graphite mold is subjected to ultrasonic vibration or rapid orientation and flattening of metal micro-sheets. The ultrasonic vibration time is 1~2 days and the vibration power is 800~2500W. The rapid orientation and flattening of metal micro-sheets includes applying voltage and magnetic field while ultrasonically vibrating the composite powder in the graphite mold. The ultrasonic vibration time is 30~240 minutes, the ultrasonic vibration power is 800~2500W, the applied voltage is 3~50V, and the applied magnetic field is 0.2~0.5T.

[0037] Step 3: The composite powder with a certain orientation obtained in Step 2, together with the graphite mold, is subjected to vacuum discharge plasma sintering. The sintering vacuum degree is -0.09~-0.1MPa, the sintering pressure is 50MPa, the sintering holding time is 30~40min, and the sintering temperature is 1500~1600℃.

[0038] Comparative Example 1:

[0039] The Nb-15Si-24Ti-4Cr-2Al-2Hf-0.6Y(at.%) alloy prepared by arc melting was subjected to heat treatment. The first stage of heat treatment involved holding at 1450℃ for 48 hours, and the second stage involved holding at 1100℃ for 10 hours. The alloy exhibited a strength of 1102.6 MPa and a room temperature fracture toughness of 32.6 MPa·m. 1 / 2 .

[0040] Comparative Example 2:

[0041] The Nb-16Si-22Ti-4Mn (at.%) alloy prepared by arc melting contains elemental Nb, Si, Ti, and Mn with a purity of over 99.95%. After arc melting, the alloy undergoes heat treatment at 1450℃ for 50 hours. The alloy exhibits a strength of 2400 MPa and a room temperature fracture toughness of 6.3 MPa·m. 1 / 2 .

[0042] Comparative Example 3:

[0043] The 63Nb-12Si-5Mo-20Ti (wt.%) alloy prepared by arc melting contains elemental Nb, Si, Mo, and Ti with a purity of over 99.5%. After arc melting, the alloy undergoes heat treatment at 1500℃ for 100 hours. The alloy exhibits a strength of 1740 MPa and a room temperature fracture toughness of 21 MPa·m. 1 / 2 .

[0044] Comparative Example 4:

[0045] The niobium-based composite material Nb / Nb5Si3, prepared by vacuum hot pressing sintering of Nb foil, consists of a slurry of Nb and Si with a purity of ≥99.9% uniformly coated onto the surface of an Nb foil with an average thickness of 20 μm, forming a slurry layer with a thickness of 10 μm. After drying, it is sintered by vacuum hot pressing at 1500–1750 °C. The room temperature fracture toughness of this composite material is 20 MPa·m. 1 / 2 .

[0046] Example 1:

[0047] This embodiment provides a biomimetic micro / nano-layered Nb / Nb5Si3 composite material, which includes an Nb5Si3 phase and a lamellar Nb phase. This biomimetic micro / nano-layered Nb / Nb5Si3 composite material is made from elemental Nb and elemental Si in an atomic ratio of 1:17.5, and the preparation process includes the following steps:

[0048] Step 1: A certain amount of raw material Nb powder, steel balls, and alcohol are loaded into a ball mill jar. The ball mill jar is subjected to a "vacuuming-argon filling" operation, which is repeated several times to ensure that the air inside the ball mill jar is discharged. The ball-to-material mass ratio is 10:1, the ball milling speed is 400 r / min, and the ball milling time is 2 hours to ball mill the Nb powder into Nb flakes. The prepared Nb flakes are first vacuum dried and then sieved to screen out small-diameter nano-Nb flakes with a diameter of 15~30μm. The screened small-diameter nano-Nb flakes and raw material Si powder are loaded into a ball mill jar at an atomic ratio of 1:17.5, and a certain amount of alcohol is added. The ball-to-material mass ratio is 10:1, the ball milling speed is 250 r / min, and the ball milling time is 4 hours. After ball milling and mixing evenly under argon protection, vacuum drying is performed at a drying temperature of 95℃ for 3 hours to obtain composite powder.

[0049] Step 2: The composite powder obtained in Step 1, together with the graphite mold, is subjected to vacuum discharge plasma sintering, wherein the sintering vacuum degree is -0.1MPa, the sintering pressure is 50MPa, the sintering holding time is 30min, and the sintering temperature is 1500℃.

[0050] The microstructure of the biomimetic micro / nano layered Nb / Nb5Si3 composite material prepared in this embodiment is as follows: Figure 1 As shown, this biomimetic micro / nano layered Nb / Nb5Si3 composite material exhibits a strength of 1920 MPa and a room-temperature fracture toughness of 12.36 MPa·m. 1 / 2 .

[0051] Example 2:

[0052] This embodiment provides a biomimetic micro / nano-layered Nb / Nb5Si3 composite material, which includes an Nb5Si3 phase and a lamellar Nb phase. This biomimetic micro / nano-layered Nb / Nb5Si3 composite material is made from elemental Nb and elemental Si in an atomic ratio of 1:17.5. The preparation process in this embodiment differs from that in Example 1 in that the composite powder obtained after step one is subjected to ultrasonic vibration for 24 hours at a power of 1800 W. This causes the randomly arranged Nb sheets within the graphite mold to exhibit directional alignment. The composite powder, along with the graphite mold, is then subjected to vacuum discharge plasma sintering.

[0053] The microstructure of the biomimetic micro / nano layered Nb / Nb5Si3 composite material prepared in this embodiment is as follows: Figure 2As shown in the figure, compared with Example 1, the microstructure of this biomimetic micro / nano layered Nb / Nb5Si3 composite material exhibits a more regular Nb phase with a lamellar structure. However, the thickness of the lamellar Nb phase layers is not uniform and the area is small, showing a certain degree of parallel and interlaced arrangement. This biomimetic micro / nano layered Nb / Nb5Si3 composite material achieves a strength of 2021 MPa at room temperature and a room temperature fracture toughness of 15.2 MPa·m. 1 / 2 .

[0054] Example 3:

[0055] This embodiment provides a biomimetic micro / nano-layered Nb / Nb5Si3 composite material, which includes an Nb5Si3 phase and a lamellar Nb phase. This biomimetic micro / nano-layered Nb / Nb5Si3 composite material is made from elemental Nb and elemental Si in an atomic ratio of 1:17.5. The preparation process in this embodiment differs from that in Example 1 in that the composite powder obtained after step one undergoes rapid orientation and planarization of metal microsheets. This rapid orientation and planarization process involves applying a 5V voltage and a 0.2T magnetic field to the composite powder within a graphite mold, followed by ultrasonic vibration for 120 minutes at a power of 1800W. This causes the randomly arranged Nb sheets within the graphite mold to exhibit directional alignment. The composite powder, along with the graphite mold, is then subjected to vacuum discharge plasma sintering.

[0056] The microstructure of the biomimetic micro / nano layered Nb / Nb5Si3 composite material prepared in this embodiment is as follows: Figure 3 As shown in the figure. Compared with Examples 1 and 2, the microstructure of this biomimetic micro / nano-layered Nb / Nb5Si3 composite material exhibits a thinner, larger, and more regularly arranged, parallel, interlaced lamellar Nb phase. The thinnest part of the lamellar Nb phase is approximately 150 nm, the thickest part is approximately 3.2 μm, and the interlayer spacing is 100–600 nm. This biomimetic micro / nano-layered Nb / Nb5Si3 composite material achieves a strength of 2314 MPa at room temperature and a room temperature fracture toughness of 34.2 MPa·m. 1 / 2Compared with Comparative Examples 1, 2, 3, Example 1, and 2, the biomimetic micro / nano layered Nb / Nb5Si3 composite material of this example achieves both strength and toughness. Compared with Example 2, this example uses rapid orientation and planarization of metal microflakes on the composite powder, which can induce directional alignment of randomly arranged Nb flakes in the graphite mold within 2 hours, greatly shortening the preparation cycle. Compared with Comparative Example 4 and Example 1, the layer thickness and interlayer spacing of the lamellar Nb phase in the biomimetic micro / nano layered Nb / Nb5Si3 composite material of this example are significantly reduced. The rapid orientation and planarization of metal microflakes on the mixed powder plays a significant role in obtaining the micro / nano layered Nb phase structure, thereby comprehensively improving the strength and toughness of the Nb / Nb5Si3 composite material.

[0057] Example 4:

[0058] This embodiment provides a biomimetic micro / nano-layered Nb / Nb5Si3 composite material, which includes an Nb5Si3 phase and a lamellar Nb phase. This biomimetic micro / nano-layered Nb / Nb5Si3 composite material is made from elemental Nb and elemental Si in an atomic ratio of 1:15, and the preparation process includes the following steps:

[0059] Step 1: A certain amount of raw material Nb powder, steel balls, and alcohol are loaded into a ball mill jar. The ball mill jar is subjected to a "vacuuming-argon filling" operation, which is repeated several times to ensure that the air inside the ball mill jar is discharged. The ball-to-material mass ratio is 10:1, the ball milling speed is 400 r / min, and the ball milling time is 2 hours to ball mill the Nb powder into Nb flakes. The prepared Nb flakes are first vacuum dried and then sieved to screen out small-diameter nano-Nb flakes with a diameter of 10~15 μm. The screened small-diameter nano-Nb flakes and raw material Si powder are loaded into a ball mill jar at an atomic ratio of 1:15, and a certain amount of alcohol is added. The ball-to-material mass ratio is 10:1, the ball milling speed is 250 r / min, and the ball milling time is 4 hours. After ball milling and mixing evenly under argon protection, vacuum drying is performed at a drying temperature of 95℃ for 3 hours to obtain composite powder.

[0060] Step 2: The dried composite powder prepared in Step 1 is loaded into a graphite mold. In order to make the randomly arranged Nb sheets in the graphite mold directional, the composite powder in the graphite mold is subjected to ultrasonic vibration for 1.5 days and the ultrasonic vibration power is 1000W.

[0061] Step 3: The composite powder obtained in Step 3, together with the graphite mold, is subjected to vacuum discharge plasma sintering, wherein the sintering vacuum degree is -0.1MPa, the sintering pressure is 50MPa, the sintering holding time is 30min, and the sintering temperature is 1500℃.

[0062] The biomimetic micro / nano-layered Nb / Nb5Si3 composite material prepared in this embodiment exhibits a relatively regular Nb phase with a lamellar structure. However, the lamellar Nb phase layers are not uniform in thickness and have a small area, showing a certain degree of parallel and interlaced arrangement. This biomimetic micro / nano-layered Nb / Nb5Si3 composite material achieves a strength of 2031 MPa and a room-temperature fracture toughness of 14.3 MPa·m at room temperature. 1 / 2 .

[0063] Example 5:

[0064] This embodiment provides a biomimetic micro / nano-layered Nb / Nb5Si3 composite material, which includes an Nb5Si3 phase and a lamellar Nb phase. This biomimetic micro / nano-layered Nb / Nb5Si3 composite material is made from elemental Nb and elemental Si in an atomic ratio of 1:15. The preparation process in this embodiment differs from that in Example 4 in that the composite powder obtained after step one undergoes rapid orientation and planarization of metal microsheets. This rapid orientation and planarization process involves applying a 32V voltage and a 0.3T magnetic field to the composite powder within a graphite mold, followed by ultrasonic vibration for 180 minutes at a power of 1000W. This causes the randomly arranged Nb sheets within the graphite mold to exhibit directional alignment. The composite powder, along with the graphite mold, is then subjected to vacuum discharge plasma sintering.

[0065] The biomimetic micro / nano-layered Nb / Nb5Si3 composite material prepared in this embodiment exhibits a microstructure of thinner, larger, and more regularly arranged parallel and interlaced lamellar Nb phases. The thinnest part of these lamellar Nb phases is approximately 30 nm, and the thickest part is approximately 1.1 μm, with an interlayer spacing of 50–800 nm. This biomimetic micro / nano-layered Nb / Nb5Si3 composite material achieves a strength of 2386 MPa and a room-temperature fracture toughness of 34.6 MPa·m at room temperature. 1 / 2 Compared with Comparative Examples 1, 2, 3, Example 1, and 4, the biomimetic micro / nano layered Nb / Nb5Si3 composite material of this example achieves both strength and toughness. Compared with Example 4, this example uses rapid orientation and planarization of metal microflakes on the composite powder, which can induce directional alignment of randomly arranged Nb flakes in the graphite mold within 3 hours, greatly shortening the preparation cycle. Compared with Comparative Examples 4 and 1, the layer thickness and interlayer spacing of the lamellar Nb phase in the biomimetic micro / nano layered Nb / Nb5Si3 composite material of this example are significantly reduced. The rapid orientation and planarization of metal microflakes on the mixed powder plays a significant role in obtaining the micro / nano layered Nb phase structure, thereby comprehensively improving the strength and toughness of the Nb / Nb5Si3 composite material.

[0066] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope of the present invention.

Claims

1. A biomimetic micro / nano layered Nb / Nb5Si3 composite material, characterized in that, The biomimetic micro-nano layered Nb / Nb5Si3 composite material includes an Nb5Si3 phase and a lamellar Nb phase, wherein the lamellar Nb phase is arranged in a parallel and interlaced manner. The biomimetic micro / nano layered Nb / Nb5Si3 composite material is prepared by the following method: raw material Si powder and small-particle-size nano Nb flakes are mixed evenly and dried to obtain composite powder; the composite powder is subjected to ultrasonic vibration or rapid orientation and planarization of metal microflakes to obtain composite powder with a certain alignment direction; the composite powder with a certain alignment direction is subjected to vacuum discharge plasma sintering to prepare the biomimetic micro / nano layered Nb / Nb5Si3 composite material. The method for rapid orientation and flattening of metal micro-flakes includes applying voltage and magnetic field while ultrasonically vibrating the composite powder. The ultrasonic vibration power is 800~2500W, the applied voltage is 3~50V, and the applied magnetic field is 0.2~0.5T.

2. The biomimetic micro / nano layered Nb / Nb5Si3 composite material according to claim 1, characterized in that, The layered Nb phase has a thickness of 10~800nm ​​and an interlayer spacing of 50~800nm.

3. The biomimetic micro / nano layered Nb / Nb5Si3 composite material according to claim 1, characterized in that, The small-particle-size Nb nanosheets have a diameter of 10~30μm and a thickness of 100~800nm.

4. The biomimetic micro / nano layered Nb / Nb5Si3 composite material according to claim 1, characterized in that, The atomic ratio of the raw material Si powder to the small-particle-size Nb nanosheets is 13~25:

1.

5. A method for preparing a biomimetic micro / nano layered Nb / Nb5Si3 composite material according to any one of claims 1 or 2, characterized in that... The method includes the following steps: Step 1: Ball mill Nb powder into Nb flakes under vacuum conditions and then vacuum dry them, and then screen out small-diameter nano Nb flakes; weigh the raw material Si powder and the screened small-diameter nano Nb flakes in proportion, ball mill them together until uniform, and then vacuum dry them to obtain composite powder; Step 2: After loading the composite powder prepared in Step 1 into a graphite mold, the composite powder in the graphite mold is subjected to ultrasonic vibration or rapid orientation and flattening of metal micro-sheets to obtain composite powder with a certain alignment direction. Step 3: The composite powder with a certain alignment direction prepared in Step 2, together with the graphite mold, is subjected to vacuum discharge plasma sintering to prepare a biomimetic micro-nano layered Nb / Nb5Si3 composite material.

6. The method according to claim 5, characterized in that, In step two, the ultrasonic vibration time is 1-2 days and the ultrasonic vibration power is 800-2500W.

7. The method according to claim 5, characterized in that, The method for rapid orientation and flattening of metal micro-flakes includes applying voltage and magnetic field while ultrasonically vibrating the composite powder, wherein the ultrasonic vibration time is 30~240min, the ultrasonic vibration power is 800~2500W, the applied voltage is 3~50V, and the applied magnetic field is 0.2~0.5T.

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