Graphene-reinforced Ti / Al3Ti micro-laminate composite material and preparation method thereof

Abstract

This invention discloses a graphene-enhanced Ti / Al 3 This invention relates to the field of metal matrix composite technology, specifically Ti micro-layer composite materials and their preparation methods. The process involves (1) preparing and spraying graphene slurry, (2) sequentially stacking different metal foils, (3) hot-pressing and sintering, and (4) high-temperature annealing after sintering to prepare graphene-reinforced Ti / Al composite materials. 3 Ti microlayer composite materials exhibit Ti layers and graphene-reinforced Al. 3 A stacked microstructure with alternating Ti layers. Graphene-reinforced Al. 3 The Ti layer, as a "hard" phase, ensures the high strength of the composite material; Ti layer, Al 3 The good bonding between the Ti layer and the graphene-reinforced phase interface is conducive to load transfer, giving the composite material good plastic deformation capacity. The Ti layer, as a "soft" phase, can effectively hinder crack propagation, and the micro-stacked structure with alternating soft and hard layers makes the crack propagation path under bending load more tortuous, which can significantly improve the toughness of the composite material.

Description

A graphene-reinforced Ti / Al3Ti microlayer composite material and its preparation method Technical Field

[0001] This invention belongs to the field of metal matrix composite technology, specifically relating to a graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method. Background Technology

[0002] Ti / Al3Ti microlaminated composites possess excellent comprehensive mechanical properties, including high compressive strength, specific modulus, fracture toughness, and low density, demonstrating great application potential in aerospace, marine engineering equipment, automotive, electronics, and defense industries. However, the intermetallic compound Al3Ti exhibits significant room-temperature brittleness, resulting in poor overall mechanical properties of Ti / Al3Ti microlaminated composites (tensile strength < 400 MPa, elongation after fracture < 4%, fracture toughness < 40 MPa·m). 1 / 2 Furthermore, its processing is limited, restricting its wider application.

[0003] In recent years, researchers have explored adding a certain amount of continuous fibers, such as SiC fibers, Al2O3 fibers, and NiTi fibers, to Ti / Al3Ti microlaminated composites to prepare fiber-reinforced Ti / Al3Ti microlaminated composites, thereby improving their tensile and processability. Under the coupling effect of fibers, the tensile strength of the composite material can be increased to ~600 MPa, but its fracture strain is not significantly improved at this point. Compared with continuous fibers, graphene, as a two-dimensional material, possesses superior comprehensive mechanical properties, including higher strength and modulus. Its tensile strength can reach ~130 GPa, and its Young's modulus is 1.0 TPa, while also exhibiting good toughness. Therefore, graphene has a more significant effect on improving the mechanical behavior of metallic materials.

[0004] Currently, graphene has been extensively studied in Ti-based and Al-based composite materials, but graphene-reinforced Ti / Al3Ti microlayer composites have not yet been reported. Therefore, whether graphene can improve the mechanical properties of Ti / Al3Ti composites and how to prepare graphene-reinforced Ti / Al3Ti microlayer composites remain unpredictable. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: First, graphene is uniformly coated on Al foil, and then it is stacked with pure Ti or Ti alloy foil in sequence to obtain a composite foil blank. Then, the composite foil blank is hot-pressed and sintered to obtain a high-density bulk material. Finally, the sintered bulk material is subjected to high-temperature annealing treatment to obtain a graphene-reinforced Ti / Al3Ti micro-stacked composite material with good strength-plasticity and strength-toughness matching, thereby achieving the purpose of the present invention.

[0007] This invention relates to a graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method, the method comprising the following steps:

[0008] (1) Graphene powder is dispersed in a volatile solvent to prepare a graphene slurry;

[0009] (2) The prepared graphene slurry is uniformly coated onto the Al foil by spraying at a temperature of 50-90°C. After spraying, the foil is placed in an oven to dry at a temperature of 60-100°C to obtain the Al foil loaded with graphene.

[0010] (3) Cut the graphene-loaded Al foil and Ti foil into sheets of specific shapes and sizes as required, and then stack the sheets of different materials in sequence. When stacking, the graphene layer in the Al foil is in contact with the Ti foil to obtain a layered composite foil blank.

[0011] (4) The layered composite foil blank is placed in a cemented carbide mold and hot-pressed for sintering: First, it is pre-sintered in an environment with a temperature of 400-500℃ and a pressure of 30-50MPa for 1-3 hours to make the composite foil blank more compact; then, it is hot-pressed for sintering in an environment with a temperature of 550-700℃ and a pressure of 3-5MPa for 1-3 hours to prevent the softened Al from being extruded; after sintering, it is air-cooled to obtain the graphene-reinforced Ti / Al3Ti micro-layered composite material blank.

[0012] (5) The graphene-reinforced Ti / Al3Ti micro-layer composite material blank obtained by hot pressing and sintering is subjected to subsequent high-temperature annealing treatment to improve the interfacial bonding between graphene and Al3Ti. The annealing temperature is 800-1000℃, the holding time is 1-6h, and the blank is air-cooled after the holding time is completed to obtain the graphene-reinforced Ti / Al3Ti micro-layer composite material.

[0013] Preferably, the Ti foil is a pure Ti foil or a Ti alloy foil, with a thickness of 90–150 μm.

[0014] Preferably, the concentration of the graphene slurry prepared in step (1) is 1 mg / mL to 3 mg / mL.

[0015] Preferably, in step (2), when the prepared graphene slurry is uniformly coated onto the Al foil, the spraying flow rate is 2-4 L / h, the single spraying time is 10-20 s, the spraying interval is not less than 20 s to prevent the slurry from overflowing, and the number of spraying times is 6-15.

[0016] Preferably, the Al foil has a thickness of 60–100 μm.

[0017] Preferably, the hot pressing reaction sintering temperature in step (4) is 575-680℃, and the holding time is 1-2h.

[0018] Preferably, the high-temperature annealing temperature in step (5) is 900-950℃ and the holding time is 3-4h.

[0019] The present invention also relates to a graphene-reinforced Ti / Al3Ti micro-layer composite material, comprising an Al foil layer and a Ti foil layer, which are stacked sequentially, wherein the surface of the Al foil layer is loaded with a graphene layer, which is in contact with the Ti foil.

[0020] The beneficial effects of this invention are:

[0021] (1) The present invention relates to a graphene-reinforced Ti / Al3Ti micro-laminated composite material and its preparation method. The micro-laminated composite material is formed by hot pressing and sintering pure Ti or Ti alloy foil, Al foil and graphene. During the sintering process, as the Al foil softens and under the coupling effect of pressure, the graphene gradually moves into the Al layer. With the extension of the holding time, the Al foil and Ti or Ti alloy foil completely react to form Al3Ti, thus obtaining a graphene-reinforced Al3Ti layer. As a "hard" phase, it ensures the high strength of the material. The good bonding between the Ti layer, Al3Ti layer and graphene-reinforced phase interface is conducive to the transfer of load, thereby giving the composite material good plastic deformation ability. At the same time, the Ti layer, as a "soft" phase, can effectively hinder crack propagation, and the alternating soft and hard micro-laminated structure makes the propagation path of cracks generated under bending load more tortuous, which can significantly improve the toughness of the composite material. Therefore, the graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared by this method has good strength-plasticity and strength-toughness matching.

[0022] (2) When the graphene is sprayed onto the Al foil surface in the method of the present invention, the graphene content is controlled by the graphene slurry concentration and the number of spraying times, thereby avoiding the defects of excessive graphene content on the foil due to the high graphene slurry concentration and the excessive number of spraying times, which can easily lead to mutual aggregation and clustering, thus limiting the strengthening and toughening effect of graphene on the Al3Ti layer and affecting the comprehensive mechanical properties of the composite material.

[0023] (3) In the method of the present invention, the hot-pressing reaction sintering temperature is 550-700℃. If the sintering temperature is lower than 550℃, the Ti or Ti alloy foil cannot react completely with the Al foil to form Al3Ti due to the low temperature, which is not conducive to improving the strength of the composite material. At the same time, at a lower temperature, the Al foil softens to a limited extent, and graphene cannot move into the Al layer during the sintering process. Instead, it concentrates at the interface between the two metal foils and cannot exert the strengthening and toughening effect of graphene on the Al3Ti intermetallic compound. When the hot-pressing sintering temperature is higher than 700℃, the Al foil melts completely due to the high sintering temperature. Under pressure, the Al liquid will flow out along the gap between the composite foil and the mold, resulting in preparation failure. On the other hand, at this temperature, graphene reacts rapidly with Ti and Al, resulting in its consumption in large quantities, which weakens the strengthening and toughening effect of graphene on the composite material.

[0024] (4) In the method of the present invention, the subsequent high-temperature annealing temperature is 800-1000℃. When the annealing temperature is below 800℃, the reaction degree between Al3Ti and graphene is low, and the interfacial bonding strength between the two is limited, resulting in poor comprehensive mechanical properties of the composite material. When the annealing temperature is above 1000℃, graphene and Al3Ti will react rapidly and violently to generate a brittle phase, which weakens the reinforcing and toughening effect of graphene on the Al3Ti layer, resulting in a reduction in the strength-plasticity and strength-toughness matching of the composite material.

[0025] (5) The graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared by the method of the present invention has a tensile strength of ~750MPa, a tensile fracture strain of ~8.0%, and a fracture toughness of ~60MPa·m. 1 / 2 The results are significantly superior to traditional Ti / Al3Ti micro-laminated composites and continuous fiber-reinforced Ti / Al3Ti micro-laminated composites. The graphene-reinforced Ti / Al3Ti micro-laminated composite of this invention exhibits excellent strength-plasticity and toughness matching, along with low density, making it promising for broad applications in both civilian and military industries. Detailed Implementation

[0026] The technical solution of the present invention will be further described in detail below with reference to the embodiments. Obviously, the embodiments described herein are only used to explain the present invention, but the present invention is not limited to these embodiments.

[0027] In the following examples, the graphene purity was >90%, the Al foil thickness was 60–100 μm, and the pure Ti or Ti alloy foil thickness was 90–150 μm. 200 sheets of each type of foil were stacked. The density of the composite material was measured using the Archimedes displacement method with a JA2003 electronic balance. Tensile strength and elongation were measured according to GB / T228-2002 using tensile stress-strain curves obtained from quasi-static tensile tests. Fracture toughness was measured using an Instron 5500R electronic universal testing machine according to the ASTM E399-06 fracture toughness test standard.

[0028] Example 1

[0029] A graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method are disclosed below.

[0030] (1) Graphene powder was dispersed in anhydrous ethanol solvent and stirred with a magnetic stirrer to ensure uniform mixing. The magnetic stirrer speed was 300 rpm and the time was 40 min to prepare a graphene slurry with a concentration of 2 mg / mL.

[0031] (2) The prepared graphene slurry was uniformly coated onto the Al foil using a fully automatic spraying machine. The Al foil thickness was 80 μm, the spraying temperature was 50℃, the spraying flow rate was 4 L / h, the single spraying time was 10 s, the spraying interval was 20 s, and the number of spraying times was 10. After the spraying was completed, the foil was placed in an oven to dry at a temperature of 60℃ to obtain the Al foil loaded with graphene.

[0032] (3) The graphene-loaded Al foil and pure Ti foil are cut into sheets of specific shapes and sizes as required. The thickness of the Ti foil is 90 μm. Then, the different sheets are stacked in sequence. When stacking, the graphene layer in the Al foil is in contact with the Ti foil to obtain a layered composite foil blank.

[0033] (4) The layered composite foil blank is placed in a cemented carbide mold and hot-pressed in a vacuum hot-pressing sintering furnace. The sintering process is divided into two steps: First, pre-sintering is carried out under the process conditions of 450℃ and 35MPa for 2 hours to make the composite foil blank more compact; then reaction sintering is carried out at 680℃, and the sintering pressure is reduced to 3MPa to prevent the softened Al from being squeezed out. The holding time is 2 hours. After sintering, it is air-cooled to obtain the graphene-reinforced Ti / Al3Ti micro-layered composite material blank.

[0034] (5) The graphene-reinforced Ti / Al3Ti micro-layer composite material blank obtained by hot pressing and sintering is subjected to subsequent high-temperature annealing treatment to improve the interfacial bonding between graphene and Al3Ti. The annealing temperature is 920℃, the holding time is 3h, and the blank is air-cooled after the holding time is completed to obtain the graphene-reinforced Ti / Al3Ti micro-layer composite material.

[0035] The graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared in this embodiment has a density of 99.3%, a tensile strength of 745 MPa, an elongation after fracture of 8.1%, and a fracture toughness of 57.8 MPa·m. 1 / 2 .

[0036] Example 2

[0037] A graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method are disclosed below.

[0038] (1) Graphene powder was dispersed in anhydrous ethanol solvent and stirred with a magnetic stirrer to ensure uniform mixing. The magnetic stirrer speed was 200 rpm and the time was 30 min to prepare a graphene slurry with a concentration of 3 mg / mL.

[0039] (2) The prepared graphene slurry was uniformly coated onto the Al foil using a fully automatic spraying machine. The Al foil thickness was 100 μm, the spraying temperature was 90℃, the spraying flow rate was 2 L / h, the single spraying time was 10 s, the spraying interval was 20 s, and the number of spraying times was 15. After the spraying was completed, the foil was placed in an oven to dry at a temperature of 60℃ to obtain the Al foil loaded with graphene.

[0040] (3) Cut the graphene-loaded Al foil and pure Ti foil into sheets of specific shapes and sizes as required. The thickness of the Ti foil is 150 μm. Then, stack the different sheets in sequence. When stacking, the graphene layer in the Al foil is in contact with the Ti foil to obtain a layered composite foil blank.

[0041] (4) The layered composite foil blank is placed in a cemented carbide mold and hot-pressed in a vacuum hot-pressing sintering furnace. The sintering process is divided into two steps: first, pre-sintering is carried out at a temperature of 500℃ and a pressure of 30MPa for 1h to make the composite foil blank more compact; then, reaction sintering is carried out at 700℃, and the sintering pressure is reduced to 3MPa to prevent the softened Al from being squeezed out. The holding time is 3h. After sintering, it is air-cooled to obtain the graphene-reinforced Ti / Al3Ti micro-stacked composite material blank.

[0042] (5) The graphene-reinforced Ti / Al3Ti micro-layer composite material blank obtained by hot pressing and sintering is subjected to subsequent high-temperature annealing treatment to improve the interfacial bonding between graphene and Al3Ti. The annealing temperature is 1000℃, the holding time is 4h, and the blank is air-cooled after the holding time is completed to obtain the graphene-reinforced Ti / Al3Ti micro-layer composite material.

[0043] The graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared in this embodiment has a density of 99.7%, a tensile strength of 730 MPa, an elongation after fracture of 7.4%, and a fracture toughness of 54.1 MPa·m. 1 / 2 .

[0044] Example 3

[0045] A graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method are disclosed below.

[0046] (1) Graphene powder was dispersed in anhydrous ethanol solvent and stirred with a magnetic stirrer to ensure uniform mixing. The magnetic stirrer speed was 300 rpm and the time was 30 min to prepare a graphene slurry with a concentration of 2 mg / mL.

[0047] (2) The prepared graphene slurry was uniformly coated onto the Al foil using a fully automatic spraying machine. The Al foil thickness was 60 μm, the spraying temperature was 80℃, the spraying flow rate was 2 L / h, the single spraying time was 10 s, the spraying interval was 30 s, and the number of spraying times was 6. After the spraying was completed, the foil was placed in an oven to dry at a temperature of 100℃ to obtain the Al foil loaded with graphene.

[0048] (3) Cut the graphene-loaded Al foil and pure Ti foil into sheets of specific shapes and sizes as required. The thickness of the Ti foil is 100 μm. Then, stack the different sheets in sequence. When stacking, the graphene layer in the Al foil is in contact with the Ti foil to obtain a layered composite foil blank.

[0049] (4) The layered composite foil blank is placed in a cemented carbide mold and hot-pressed in a vacuum hot-pressing sintering furnace. The sintering process is divided into two steps: first, pre-sintering is carried out at a temperature of 500℃ and a pressure of 30MPa for 1h to make the composite foil blank more compact; then, reaction sintering is carried out at 575℃, and the sintering pressure is reduced to 5MPa to prevent the softened Al from being squeezed out. The holding time is 3h. After sintering, it is air-cooled to obtain the graphene-reinforced Ti / Al3Ti micro-stacked composite material blank.

[0050] (5) The graphene-reinforced Ti / Al3Ti micro-layer composite material blank obtained by hot pressing and sintering is subjected to subsequent high-temperature annealing treatment to improve the interfacial bonding between graphene and Al3Ti. The annealing temperature is 950℃, the holding time is 1h, and the blank is air-cooled after the holding time is completed to obtain the graphene-reinforced Ti / Al3Ti micro-layer composite material.

[0051] The graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared in this embodiment has a density of 99.0%, a tensile strength of 705 MPa, an elongation after fracture of 7.5%, and a fracture toughness of 51.9 MPa·m. 1 / 2 .

[0052] Example 4

[0053] A graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method are disclosed below.

[0054] (1) Graphene powder was dispersed in anhydrous ethanol solvent and stirred with a magnetic stirrer to ensure uniform mixing. The magnetic stirrer speed was 200 rpm and the time was 30 min to prepare a graphene slurry with a concentration of 1 mg / mL.

[0055] (2) The prepared graphene slurry was uniformly coated onto the Al foil using a fully automatic spraying machine. The Al foil thickness was 60 μm, the spraying temperature was 80℃, the spraying flow rate was 2 L / h, the single spraying time was 10 s, the spraying interval was 20 s, and the number of spraying times was 12. After the spraying was completed, the foil was placed in an oven to dry at a temperature of 60℃ to obtain the Al foil loaded with graphene.

[0056] (3) The graphene-loaded Al foil and pure Ti foil are cut into sheets of specific shapes and sizes as required. The thickness of the Ti foil is 90 μm. Then, the different sheets are stacked in sequence. When stacking, the graphene layer in the Al foil is in contact with the Ti foil to obtain a layered composite foil blank.

[0057] (4) The layered composite foil blank is placed in a cemented carbide mold and hot-pressed in a vacuum hot-pressing sintering furnace. The sintering process is divided into two steps: first, pre-sintering is carried out at a temperature of 500℃ and a pressure of 40MPa for 3 hours to make the composite foil blank more compact; then, reaction sintering is carried out at 640℃, and the sintering pressure is reduced to 3MPa to prevent the softened Al from being squeezed out. The holding time is 1 hour. After sintering, it is air-cooled to obtain the graphene-reinforced Ti / Al3Ti micro-stacked composite material blank.

[0058] (5) The graphene-reinforced Ti / Al3Ti micro-layer composite material blank obtained by hot pressing and sintering is subjected to subsequent high-temperature annealing treatment to improve the interfacial bonding between graphene and Al3Ti. The annealing temperature is 900℃, the holding time is 3h, and the blank is air-cooled after the holding time is completed to obtain the graphene-reinforced Ti / Al3Ti micro-layer composite material.

[0059] The graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared in this embodiment has a density of 99.3%, a tensile strength of 695 MPa, an elongation after fracture of 7.4%, and a fracture toughness of 53.7 MPa·m. 1 / 2 .

[0060] Example 5

[0061] A graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method are disclosed below.

[0062] (1) Graphene powder was dispersed in anhydrous ethanol solvent and stirred with a magnetic stirrer to ensure uniform mixing. The magnetic stirrer speed was 200 rpm and the time was 30 min to prepare a graphene slurry with a concentration of 1 mg / mL.

[0063] (2) The prepared graphene slurry was uniformly coated onto the Al foil using a fully automatic spraying machine. The Al foil thickness was 100 μm, the spraying temperature was 80℃, the spraying flow rate was 2 L / h, the single spraying time was 10 s, the spraying interval was 30 s, and the number of spraying times was 9. After the spraying was completed, the foil was placed in an oven to dry at a temperature of 60℃ to obtain the Al foil loaded with graphene.

[0064] (3) The graphene-loaded Al foil and TC4 titanium alloy foil are cut into sheets of specific shapes and sizes as required. The thickness of the TC4 foil is 120 μm. Then, the different sheets are stacked in sequence. When stacking, the graphene layer in the Al foil is in contact with the TC4 foil to obtain a layered composite foil blank.

[0065] (4) The layered composite foil blank is placed in a cemented carbide mold and hot-pressed in a vacuum hot-pressing sintering furnace. The sintering process is divided into two steps: first, pre-sintering is carried out at a temperature of 400℃ and a pressure of 50MPa for 1h to make the composite foil blank more compact; then, reaction sintering is carried out at 550℃, and the sintering pressure is reduced to 3MPa to prevent the softened Al from being squeezed out. The holding time is 3h. After sintering, it is air-cooled to obtain the graphene-reinforced Ti / Al3Ti micro-stacked composite material blank.

[0066] (5) The graphene-reinforced Ti / Al3Ti micro-layer composite material blank obtained by hot pressing and sintering is subjected to subsequent high-temperature annealing treatment to improve the interfacial bonding between graphene and Al3Ti. The annealing temperature is 800℃, the holding time is 6h, and the blank is air-cooled after the holding time is completed to obtain the graphene-reinforced Ti / Al3Ti micro-layer composite material.

[0067] The graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared in this embodiment has a density of 98.8%, a tensile strength of 730 MPa, an elongation after fracture of 6.5%, and a fracture toughness of 55.3 MPa·m. 1 / 2 .

[0068] Comparative Example 1

[0069] A graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method are disclosed below.

[0070] (1) Graphene powder was dispersed in anhydrous ethanol solvent and stirred with a magnetic stirrer to ensure uniform mixing. The magnetic stirrer speed was 300 rpm and the stirring time was 40 min to prepare a graphene slurry with a concentration of 4 mg / mL.

[0071] (2) The prepared graphene slurry was uniformly coated onto the Al foil using a fully automatic spraying machine. The Al foil thickness was 80 μm, the spraying temperature was 50℃, the spraying flow rate was 4 L / h, the single spraying time was 10 s, the spraying interval was 20 s, and the number of spraying times was 20. After the spraying was completed, the foil was placed in an oven to dry at a temperature of 60℃ to obtain the Al foil loaded with graphene.

[0072] (3) The graphene-loaded Al foil and pure Ti foil are cut into sheets of specific shapes and sizes as required. The thickness of the Ti foil is 90 μm. Then, the different sheets are stacked in sequence. When stacking, the graphene layer in the Al foil is in contact with the Ti foil to obtain a layered composite foil blank.

[0073] (4) The layered composite foil blank is placed in a cemented carbide mold and hot-pressed in a vacuum hot-pressing sintering furnace. The sintering process is divided into two steps: first, pre-sintering is carried out at a temperature of 450℃ and a pressure of 35MPa for 1h to make the composite foil blank more compact; then, reaction sintering is carried out at 680℃, and the sintering pressure is reduced to 3MPa to prevent the softened Al from being squeezed out. The holding time is 2h. After sintering, it is air-cooled to obtain the graphene-reinforced Ti / Al3Ti micro-stacked composite material blank.

[0074] (5) The graphene-reinforced Ti / Al3Ti micro-layer composite material blank obtained by hot pressing and sintering is subjected to subsequent high-temperature annealing treatment to improve the interfacial bonding between graphene and Al3Ti. The annealing temperature is 920℃, the holding time is 3h, and the blank is air-cooled after the holding time is completed to obtain the graphene-reinforced Ti / Al3Ti micro-layer composite material.

[0075] The graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared in this comparative example has a density of 99.1%, a tensile strength of 625 MPa, an elongation after fracture of 5.3%, and a fracture toughness of 38.5 MPa·m. 1 / 2 .

[0076] As can be seen from Example 1 and Comparative Example 1, under the same foil thickness and sintering and annealing conditions, when the graphene slurry concentration is too high and the number of spraying times is too many, the strength, elongation after fracture and fracture toughness of the graphene-reinforced Ti / Al3Ti micro-stacked composite material are significantly reduced, and a good balance between strength and toughness cannot be achieved.

[0077] Comparative Example 2

[0078] A graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method are disclosed below.

[0079] (1) Graphene powder was dispersed in anhydrous ethanol solvent and stirred with a magnetic stirrer to ensure uniform mixing. The magnetic stirrer speed was 200 rpm and the time was 30 min to prepare a graphene slurry with a concentration of 1 mg / mL.

[0080] (2) The prepared graphene slurry was uniformly coated onto the Al foil using a fully automatic spraying machine. The Al foil thickness was 60 μm, the spraying temperature was 80℃, the spraying flow rate was 2 L / h, the single spraying time was 10 s, the spraying interval was 20 s, and the number of spraying times was 12. After the spraying was completed, the foil was placed in an oven to dry at a temperature of 60℃ to obtain the Al foil loaded with graphene.

[0081] (3) The graphene-loaded Al foil and pure Ti foil are cut into sheets of specific shapes and sizes as required. The thickness of the Ti foil is 90 μm. Then, the different sheets are stacked in sequence. When stacking, the graphene layer in the Al foil is in contact with the Ti foil to obtain a layered composite foil blank.

[0082] (4) The layered composite foil blank is placed in a cemented carbide mold and hot-pressed in a vacuum hot-pressing sintering furnace. The sintering process is divided into two steps: first, pre-sintering is carried out at a temperature of 500℃ and a pressure of 40MPa for 3 hours to make the composite foil blank more compact; then, reaction sintering is carried out at 450℃, the sintering pressure is 3MPa, the holding time is 1 hour, and after sintering, it is air-cooled to obtain the graphene-reinforced Ti / Al3Ti micro-layered composite material blank.

[0083] (5) The graphene-reinforced Ti / Al3Ti micro-layer composite material blank obtained by hot pressing and sintering is subjected to subsequent high-temperature annealing treatment to improve the interfacial bonding between graphene and Al3Ti. The annealing temperature is 900℃, the holding time is 3h, and the blank is air-cooled after the holding time is completed to obtain the graphene-reinforced Ti / Al3Ti micro-layer composite material.

[0084] The graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared in this comparative example has a density of 95.8%, a tensile strength of 415 MPa, an elongation after fracture of 6.9%, and a fracture toughness of 24.2 MPa·m. 1 / 2 .

[0085] As can be seen from Example 4 and Comparative Example 2, under the same conditions of graphene content, sintering pressure, and subsequent annealing temperature, when the reaction sintering temperature is low, although the graphene-reinforced Ti / Al3Ti micro-stacked composite material still has good plastic deformation ability, its strength and fracture toughness are significantly reduced, and it is impossible to achieve a good match between strength and plasticity and strength and toughness.

[0086] Comparative Example 3

[0087] A graphene-reinforced Ti / Al3Ti micro-layer composite material and its preparation method are disclosed below.

[0088] (1) Graphene powder was dispersed in anhydrous ethanol solvent and stirred with a magnetic stirrer to ensure uniform mixing. The magnetic stirrer speed was 200 rpm and the time was 30 min to prepare a graphene slurry with a concentration of 1 mg / mL.

[0089] (2) The prepared graphene slurry was uniformly coated onto the Al foil using a fully automatic spraying machine. The Al foil thickness was 60 μm, the spraying temperature was 80℃, the spraying flow rate was 2 L / h, the single spraying time was 10 s, the spraying interval was 20 s, and the number of spraying times was 12. After the spraying was completed, the foil was placed in an oven to dry at a temperature of 60℃ to obtain the Al foil loaded with graphene.

[0090] (3) The graphene-loaded Al foil and pure Ti foil are cut into sheets of specific shapes and sizes as required. The thickness of the Ti foil is 90 μm. Then, the different sheets are stacked in sequence. When stacking, the graphene layer in the Al foil is in contact with the Ti foil to obtain a layered composite foil blank.

[0091] (4) The layered composite foil blank is placed in a cemented carbide mold and hot-pressed in a vacuum hot-pressing sintering furnace. The sintering process is divided into two steps: first, pre-sintering is carried out at a temperature of 500℃ and a pressure of 40MPa for 3 hours to make the composite foil blank more compact; then, reaction sintering is carried out at 640℃, and the sintering pressure is reduced to 3MPa to prevent the softened Al from being squeezed out. The holding time is 1 hour. After sintering, it is air-cooled to obtain the graphene-reinforced Ti / Al3Ti micro-stacked composite material blank.

[0092] (5) The graphene-reinforced Ti / Al3Ti micro-layer composite material blank obtained by hot pressing and sintering is subjected to subsequent high-temperature annealing treatment to improve the interfacial bonding between graphene and Al3Ti. The annealing temperature is 1100℃, the holding time is 2h, and the blank is air-cooled after the holding time is completed to obtain the graphene-reinforced Ti / Al3Ti micro-layer composite material.

[0093] The graphene-reinforced Ti / Al3Ti micro-laminated composite material prepared in this comparative example has a density of 99.2%, a tensile strength of 450 MPa, an elongation after fracture of 2.9%, and a fracture toughness of 27.1 MPa·m. 1 / 2 .

[0094] As can be seen from Example 4 and Comparative Example 3, under the premise of the same graphene content and sintering process, when the subsequent high-temperature annealing temperature is too high, the tensile strength, elongation after fracture and fracture toughness of the graphene-reinforced Ti / Al3Ti micro-laminated composite material all decrease significantly, resulting in an unsatisfactory match between strength and toughness.

[0095] In summary, the invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered to be within the protection scope of this invention.

Claims

1. A method for preparing graphene-reinforced Ti / Al3Ti micro-layer composite material, characterized in that, The method includes the following steps: (1) dispersing graphene powder in a volatile solvent to prepare a graphene slurry; (2) uniformly coating the prepared graphene slurry onto an Al foil using a spraying method at a temperature of 50-90°C; after spraying, placing the foil in an oven to dry at a temperature of 60-100°C to obtain an Al foil loaded with graphene; (3) cutting the Al foil loaded with graphene into sheets with a thickness of 60-100 μm, and cutting the Ti foil into sheets with a thickness of 90-150 μm (pure Ti foil or Ti alloy foil), and then stacking the sheets of different materials in sequence, with the graphene layer in the Al foil in contact with the Ti foil sheet during placement to obtain a layered composite foil blank; (4) placing the layered composite foil blank into a hard alloy mold for hot pressing and sintering. First, pre-sintering is carried out in an environment with a temperature of 400-500℃ and a pressure of 30-50MPa for 1-3 hours to make the composite foil blank more compact; then, hot pressing reaction sintering is carried out in an environment with a temperature of 550-700℃ and a pressure of 3-5MPa for 1-3 hours to prevent the softened Al from being squeezed out; after sintering, air cooling is performed to obtain graphene-reinforced Ti / Al3Ti micro-stacked composite material blank; (5) The graphene-reinforced Ti / Al3Ti micro-stacked composite material blank obtained by hot pressing sintering is subjected to subsequent high-temperature annealing treatment to improve the interface bonding between graphene and Al3Ti. The annealing temperature is 800-1000℃, the holding time is 1-6 hours, and after the holding time is completed, air cooling is performed to obtain graphene-reinforced Ti / Al3Ti micro-stacked composite material.

2. The method for preparing a graphene-reinforced Ti / Al3Ti micro-layer composite material according to claim 1, characterized in that: The concentration of the graphene slurry prepared in step (1) is 1 mg / mL to 3 mg / mL.

3. The method for preparing a graphene-reinforced Ti / Al3Ti micro-layer composite material according to claim 1, characterized in that: In step (2), when the prepared graphene slurry is uniformly coated onto the Al foil, the spraying flow rate is 2-4 L / h, the single spraying time is 10-20 s, the spraying interval is not less than 20 s to prevent the slurry from overflowing, and the number of spraying times is 6-15.

4. The method for preparing a graphene-reinforced Ti / Al3Ti micro-layer composite material according to claim 1, characterized in that: In step (4), the hot pressing reaction sintering temperature is 575-680℃, and the holding time is 1-2h.

5. The method for preparing a graphene-reinforced Ti / Al3Ti micro-layer composite material according to claim 1, characterized in that: In step (5), the high-temperature annealing temperature is 900-950℃ and the holding time is 3-4h.