Heat-resistant high-strength aluminum alloy material and preparation method thereof

Abstract

The application provides a heat-resistant high-strength aluminum alloy material and a preparation method thereof. Raw material components of the aluminum alloy material are as follows in percentage by mass: 0.3-0.6wt% of Fe, 0.8-1.5wt% of Mg, 0.1-0.3wt% of Mn, 0.7-0.9wt% of Zn, 0.2-0.3wt% of Cr, 0.2-0.3wt% of Ti, 1.5-3wt% of Ni, 0.5-1.0wt% of Co, 0.3-0.8wt% of Sc, 1.2-3.6wt% of modified graphene, and the balance of Al; wherein the modified graphene is a copper / graphene / silicon composite material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal materials, in particular to a heat-resistant high-strength aluminum alloy material and a preparation method thereof. BACKGROUND

[0002] Graphene is a two-dimensional material composed of carbon atoms in sp 2 hybridized orbitals arranged in a hexagonal honeycomb lattice. It has attracted much attention due to its unique physical and chemical properties. Graphene has extremely high thermal and electrical conductivity, as well as mechanical strength, making it have wide application prospects in electronics, energy, biomedicine and other fields. The thickness of graphene is only one carbon atom, but its mechanical strength is 200 times that of steel. At the same time, graphene has extremely high electron mobility, making the movement of electrons in graphene extremely fast, so graphene has great application potential in electronic devices. In addition, graphene also has extremely high thermal conductivity, making it have important application value in thermal management.

[0003] Copper, as a common metal element, can significantly improve the performance of graphene when doped. Copper-doped graphene refers to introducing copper elements into the graphene structure to change its electronic structure and surface properties, thereby improving the performance of graphene. Copper doping can significantly improve the electrical conductivity and thermal conductivity of graphene. The introduction of copper elements can increase the electron density of graphene, thereby improving its electrical conductivity. At the same time, the high thermal conductivity of the doped copper elements also helps to improve the thermal conductivity performance of graphene. In addition, copper doping can also improve the mechanical properties of graphene, so that copper-doped graphene (copper / graphene composite material) exhibits better mechanical properties during stretching and compression.

[0004] According to the characteristics of the above copper / graphene composite material, adding the copper / graphene composite material to the aluminum alloy can improve the heat resistance and mechanical properties of the aluminum alloy. However, adding the copper / graphene composite material to the aluminum alloy brings new problems. Although the copper / graphene composite material can improve the mechanical properties of the aluminum alloy, the graphene in the copper / graphene composite material is easy to react with aluminum at high temperatures after contact, generating a brittle aluminum-carbon phase Al4C3. The aluminum-carbon phase Al4C3 has hygroscopicity, which reduces the mechanical properties and heat resistance of the aluminum alloy material, affecting the service life of the aluminum alloy.

[0005] Therefore, it is urgent to develop a heat-resistant high-strength aluminum alloy material to ensure that no brittle aluminum-carbon phase Al4C3 is formed after adding the copper / graphene composite material to the aluminum alloy, to ensure good mechanical properties and heat resistance, so as to meet the actual needs of industrial production. SUMMARY

[0006] In view of the problem that the existing aluminum alloy is easy to form brittle aluminum-carbon phase Al4C3 after adding copper / graphene composite material, which reduces the mechanical properties and heat resistance of the aluminum alloy material and affects the service life of the aluminum alloy, the application provides a heat-resistant high-strength aluminum alloy material and a preparation method thereof.

[0007] In one aspect, the application provides a heat-resistant high-strength aluminum alloy material, the raw material components of the aluminum alloy material are as follows in percentage by mass: 0.3-0.6wt% of Fe, 0.8-1.5wt% of Mg, 0.1-0.3wt% of Mn, 0.7-0.9wt% of Zn, 0.2-0.3wt% of Cr, 0.2-0.3wt% of Ti, 1.5-3wt% of Ni, 0.5-1.0wt% of Co, 0.3-0.8wt% of Sc, 1.2-3.6wt% of modified graphene, and the balance is Al; wherein the modified graphene is a copper / graphene / silicon composite material.

[0008] In another aspect, the application provides a preparation method of a heat-resistant high-strength aluminum alloy material, comprising the following preparation steps: S1, preparing modified graphene: configuring a divalent copper solution as an electrolyte, and preparing the modified graphene by using a two-time electroplating method under the action of direct current; wherein the specific operation of the electroplating method is as follows: selecting two copper foils as a cathode and an anode respectively, coating graphene on the copper foil as the anode, performing first-time electroplating, electrically treating the graphene, and generating a copper / graphene composite material on the cathode; taking out the copper foil with the copper / graphene composite material and using it as the cathode for second-time electroplating, using a copper foil coated with nano-silicon as the anode, and electroplating the copper foil with the copper / graphene composite material to prepare a copper / graphene / silicon composite material; S2, preparing an aluminum alloy material: mixing Fe, Mg, Mn, Zn, Cr, Ti, Ni, Co, Sc, Al and the modified graphene prepared in S1 according to the proportion to obtain a first mixture, performing ball milling treatment on the first mixture to obtain a second mixture, and then performing heat treatment on the second mixture to obtain the aluminum alloy material.

[0009] As an implementation form, in S1, the surface area and thickness of the copper foil used for the anode in the two-time electroplating method are consistent.

[0010] As an implementation form, in S1, the divalent copper solution in the electrolyte is a copper sulfate solution or a copper pyrophosphate solution, and / or the concentration of the divalent copper solution is 30g / L-210g / L.

[0011] As an implementation form, in S1, the mass ratio of the nano-silicon particles to the graphene is (3-8):1.

[0012] As an implementation form, in the S1, the direct current has a current size of 50 mA-200 mA.

[0013] As an implementation form, in the S1, the electroplating method has a reaction time of 8 h-20 h.

[0014] As an implementation form, in the S2, the first mixture is subjected to a ball milling treatment, a ball-to-material ratio is (3-8):1, a ball-to-material rotation speed is 200 rpm-500 rpm, and a ball milling time is 5 h-10 h.

[0015] As an implementation form, in the S2, the second mixture is subjected to a heat treatment, and the heat treatment comprises vacuum high-temperature sintering of the second mixture.

[0016] As an implementation form, the sintering temperature is 570℃-700℃, and the sintering time is 20 min-90 min.

[0017] The heat-resistant high-strength aluminum alloy material provided in the application has the following effects:

[0018] (1) The heat-resistant high-strength aluminum alloy material prepared in the application adds the copper / graphene / silicon composite material to the aluminum alloy, which can not only improve the heat resistance and dispersion performance of the aluminum alloy, but also improve the mechanical performance of the aluminum alloy. In the copper / graphene / silicon composite material, the graphene is coated by the nano-silicon particles and copper. The graphene will not contact the aluminum, which avoids the interface reaction and the generation of brittle aluminum-carbon phase Al4C3 at high temperature. The silicon crystal has a high melting point of 1410℃, high temperature resistance, high hardness, and low chemical activity at room temperature. The silicon crystal can be used to coat the graphene together with the copper, and further improve the heat resistance and mechanical performance of the aluminum alloy through its own performance, thereby increasing the service life of the aluminum alloy.

[0019] (2) The copper / graphene / silicon composite material is prepared by the electroplating method, which has a simple process, low cost, and is suitable for industrial production. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the application clearer, the application will be further described in detail below with reference to examples. It should be understood that the specific examples described herein are only used to explain the application and not to limit the application.

[0021] In order to illustrate the technical scheme of the application, the following specific examples are used for illustration.

[0022] In one aspect, the present application provides a heat-resistant high-strength aluminum alloy material, raw material components of the aluminum alloy material are as follows in percentage by mass: 0.3-0.6wt% of Fe, 0.8-1.5wt% of Mg, 0.1-0.3wt% of Mn, 0.7-0.9wt% of Zn, 0.2-0.3wt% of Cr, 0.2-0.3wt% of Ti, 1.5-3.0wt% of Ni, 0.5-1.0wt% of Co, 0.3-0.8wt% of Sc, 1.2-3.6wt% of modified graphene, and the balance of Al; wherein the modified graphene is a copper / graphene / silicon composite material.

[0023] In the heat-resistant high-strength aluminum alloy material provided by the application, 0.3-0.6wt% of Fe can improve the cutting machinability and wear resistance of the alloy; Mg is mainly used to improve the strength and toughness of the aluminum alloy, while reducing the weight, and the range of 0.8-1.5wt% optimizes the strength-weight ratio, wherein the lower value (0.8%) ensures sufficient formability, and the higher value (1.5%) maximizes the strengthening effect and avoids stress corrosion cracking caused by excessive amount; Mn is mainly used to improve the weldability and corrosion resistance of the aluminum alloy, and by forming fine dispersed phases, it prevents intergranular corrosion and improves thermal stability, and 0.1-0.3wt% of Mn ensures that the welding performance is optimized without compromising toughness, wherein the lower value (0.1%) avoids brittleness, and the higher value (0.3%) enhances corrosion protection; after the addition of Mn, the aluminum alloy is more durable in marine or high-humidity environments; it can also refine the grains and improve the overall mechanical properties. Zn is mainly used to improve the corrosion resistance of the aluminum alloy, and is often used for corrosion prevention treatment, and by forming a protective oxide layer or synergistically acting with other elements, 0.7-0.9wt% of Zn balances the corrosion prevention effect and cost. The lower value (0.7%) prevents stress corrosion caused by excessive zinc, and the higher value (0.9%) enhances protection; Cr is mainly used to enhance the corrosion resistance and high-temperature stability of the aluminum alloy, and 0.2-0.3wt% of Cr is intended to fine-tune the corrosion resistance without affecting the machinability.The lower value (0.2%) reduces the cost, and the higher value (0.3%) strengthens the protection; Ti is mainly used in the aluminum alloy to enhance the heat resistance and fatigue resistance of the aluminum alloy, specifically, 0.2-0.3wt% of Ti optimizes the grain refinement effect, the lower value (0.2%) ensures the economy, and the higher value (0.3%) maximizes the high-temperature performance, after the addition of titanium, the alloy is more durable (fatigue resistance) under cyclic loading, and the high melting point improves the thermal stability; Ni is mainly used in the aluminum alloy to improve the high-temperature strength and corrosion resistance, among them, 1.5-3wt% of Ni aims to enhance the thermal stability, the lower value (1.5%) avoids brittleness, and the higher value (3%) optimizes the high-temperature strength; Co is mainly used in the aluminum alloy to improve the hardness and wear resistance, or as an alloying element to enhance the comprehensive performance, among them, 0.5-1.0wt% of Co aims to balance the strengthening and cost, the lower value (0.5%) reduces the influence, and the higher value (1.0%) enhances the mechanical properties, at the same time, Co can improve the high-temperature behavior of the aluminum alloy; Sc is mainly used in the aluminum alloy for grain refinement or to improve the weldability, among them, 0.3-0.8wt% of Sc aims to optimize the refinement effect, the lower value (0.3%) prevents excess, and the higher value (0.8%) enhances the strength, after the addition of Sc, the toughness and crack resistance of the aluminum alloy are improved to a certain extent; finally, 1.2-3.6wt% of modified graphene is added, and the modified graphene is specifically a copper / graphene / silicon composite material, the addition of the copper / graphene / silicon composite material to the aluminum alloy not only improves the heat resistance and dispersion performance of the aluminum alloy, but also improves the mechanical properties of the aluminum alloy, and in the copper / graphene composite material, the graphene is coated by nano-silicon particles and newly deposited copper, after the graphene is not in contact with aluminum, the interface reaction between the two at high temperature and the generation of brittle aluminum-carbon phase Al4C3 are avoided, at the same time, the melting point of the silicon crystal is 1410°C, the melting point is high and resistant to high temperature, the hardness is large, the chemical properties are not active at room temperature, and the copper / graphene can be coated, at the same time, the heat resistance and mechanical properties of the aluminum alloy are further improved by the performance of the silicon crystal, and the service life of the aluminum alloy is increased.

[0024] In another aspect, the present application provides a preparation method of a heat-resistant high-strength aluminum alloy material, comprising the following steps:

[0025] S1, preparing modified graphene: configuring a divalent copper solution as an electrolyte, and using a two-time electroplating method to prepare modified graphene under the action of direct current; wherein the specific operation of the electroplating method is: selecting two pieces of copper foil as cathode and anode respectively, coating graphene on the copper foil as anode, carrying out the first electroplating, and electrically treating the graphene to generate copper / graphene composite material on the cathode; taking out the copper foil with copper / graphene composite material and using it as the cathode for the second electroplating, using the copper foil coated with nano-silicon as the anode, and electroplating the copper foil with copper / graphene composite material to prepare copper / graphene / silicon composite material; S2, preparing aluminum alloy material: mixing Fe, Mg, Mn, Zn, Cr, Ti, Ni, Co, Sc, Al and the modified graphene prepared in S1 according to the proportion to obtain a first mixture, ball milling the first mixture to obtain a second mixture, and then heat treating the second mixture to obtain the aluminum alloy material.

[0026] Specifically, in S1, the electroplating method as a simple and economical process technology maintains the inherent properties of graphene in the preparation process, so that the performance of the obtained composite material is better. In S2, the ball milling treatment can ensure that the metal powder and the modified graphene are mixed uniformly and fully contacted, and the heat treatment can ensure the full combination of the metal elements and the modified graphene, so that the aluminum alloy material with excellent performance is prepared.

[0027] Specifically, the electroplating method keeps the inherent properties of graphene during the preparation of the composite material, so that the performance of the composite material is better. Most of the existing electroplating methods directly use graphene film as a cathode sheet for electroplating. However, due to the smooth surface of the graphene film and the chemical inertness, the graphene film is easy to separate from the newly deposited copper layer on its surface, and it is difficult to prepare copper / graphene composite material. In the present application, graphene is used as raw material, graphene is coated on the copper foil as anode, graphene is used as the coating of the anode, then by using electron transfer (electrophoresis), under the action of direct current power, the graphene attached to the surface of the anode will be stripped from the surface of the copper sheet under the strong oxidation reaction near the anode and the physical disturbance of the bubbles generated, and dispersed into the electrolyte containing divalent copper. When the negatively charged cathode surface is receiving the reduction and deposition of copper layer by divalent copper ions, the graphene particles dispersed in the electrolyte will also reach the cathode surface; these graphene particles will be mechanically embedded into the growing copper lattice, and the newly deposited copper atoms will tightly wrap these graphene particles, thereby forming a stable copper / graphene composite material, and the copper particles are coated on the surface of the graphene by the interelectronic force and do not change the characteristic structure. Subsequently, the copper foil with copper / graphene composite material is taken out and placed in another electroplating tank, the copper foil with copper / graphene composite material is used as the cathode for the second electroplating, the copper foil coated with nano-silicon is used as the anode, and the copper foil with copper / graphene composite material is electroplated. The dispersion operation is carried out on the electrolyte containing divalent copper, which includes ultrasonic treatment of the electrolyte or adding dispersants such as sodium dodecyl sulfate and polyvinylpyrrolidone into the electrolyte, so that the nano-silicon particles can be dispersed in the solution environment of the electrolyte to form a stable suspension. For micrometer / nanometer scale particles, there is a solvent drag effect, which is often stronger than the electrostatic force acting directly on the particles, so the negatively charged nano-silicon particles will actually move together with the liquid flow towards the cathode, and therefore the negatively charged nano-silicon particles will also migrate to the cathode under the wrapping of divalent copper ions. The divalent copper ions together with the negatively charged nano-silicon particles are attached to the surface of the copper / graphene composite material, and the nano-silicon particles and the newly deposited copper layer completely wrap the copper / graphene composite material, thereby preparing a copper / graphene / silicon composite material.

[0028] As an embodiment, in S1, the surface area and thickness of the copper foil used as the anode in the two electroplating methods are consistent, which reduces the difficulty of the two electroplating operations.

[0029] As an embodiment, in S1, the divalent copper solution in the electrolyte is a copper sulfate solution or a copper pyrophosphate solution, and / or the concentration of the divalent copper solution is 30 g / L-210 g / L.

[0030] Specifically, the electrolyte provides divalent copper ions (Cu²⁺) and carries the graphene particles dispersed in the electrolyte to the cathode, and Cu²⁺ is reduced to Cu atoms; graphene is reduced on the surface of the cathode and embedded in the copper lattice to form a copper / graphene composite material. Among them, the divalent copper solution in the electrolyte is a copper sulfate solution or a copper pyrophosphate solution, even if the electroplating reaction time is too long, no toxic gas will be electrolyzed out; further, the concentration of the divalent copper solution can be any value in 30g / L-210g / L, such as 30g / L, 50g / L, 70g / L, 90g / L, 120g / L, 150g / L, 170g / L, 190g / L, 210g / L. Increasing the concentration of the divalent copper solution is conducive to increasing the copper content in the copper / graphene composite material and improving the thermal conductivity and mechanical properties of the copper / graphene composite material.

[0031] As an implementation, in S1, the mass ratio of the nano-silicon particles to the graphene is (3-8):1. The mass ratio of the nano-silicon particles to the graphene can be any value in (3-8):1, such as 3:1, 4:1, 5:1, 6:1, 7:1, 8:1. The reason for using nano-silicon particles is that the nano-silicon is negatively charged in the solution system, and there is a solvent drag effect on micron / nano-scale particles, which is often stronger than the electrostatic force acting directly on the particles. Therefore, the negatively charged nano-silicon particles will actually move together with the liquid flow towards the cathode, thereby adhering to the surface of the copper / graphene composite material and being coated with the newly deposited copper. The mass ratio of the nano-silicon particles to the graphene is controlled to be (3-8):1, and the excess of the nano-silicon ensures that it can completely coat the graphene in the copper / graphene composite material, thereby avoiding the generation of brittle aluminum carbon phase when the aluminum alloy is prepared subsequently. At the same time, the melting point of the silicon crystal is 1410℃, which is high in melting point, high in temperature resistance, large in hardness, and chemically inert at room temperature. Therefore, the nano-silicon particles can not only be used to coat the copper / graphene composite material, but also can further improve the heat resistance and mechanical properties of the aluminum alloy and increase the service life of the aluminum alloy.

[0032] As an implementation, in S1, the current size of the direct current is 50mA-200mA. The current size of the direct current can be any value in 50mA-200mA, such as 50mA, 60mA, 70mA, 80mA, 90mA, 100mA, 110mA, 120mA, 130mA, 140mA, 150mA, 160mA, 170mA, 180mA, 190mA, 200mA.

[0033] Specifically, by controlling the current size of the direct current, and further controlling the moving speed of the graphene, nano-silicon particles and divalent copper ions in the solution environment, in the first electroplating, the direct current source provides a large current to make the graphene dispersed into the electrolyte, and the divalent copper ions in the electrolyte come to the cathode, and then the divalent copper ions in the electrolyte are reduced to elemental copper in the form of inserting into the graphene structure, and in the second electroplating, the current size of the direct current is reduced, so that the negatively charged nano-silicon can be slowly and uniformly attached to the copper / graphene composite material, ensuring the integrity and uniformity of the nano-silicon coating.

[0034] As an embodiment, in S1, the reaction time of the electroplating method is 8h-20h. Wherein, the reaction time of the electroplating method can be any value in 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, etc.

[0035] As an embodiment, in S1, the reaction time of the electroplating method is 10h-15h.

[0036] Specifically, the electroplating method is a continuous deposition process, and the copper content in the copper / graphene composite material increases with the increase of the electroplating time, and increasing the reaction time helps to increase the copper content in the copper / graphene composite material, and further improves the thermal conductivity and mechanical properties of the composite material.

[0037] As an embodiment, in S2, the first mixture is subjected to ball milling treatment, the ball-to-material ratio is (3-8):1, the ball-to-material rotation speed is 200rpm-500rpm, and the ball milling time is 5h-10h.

[0038] As an embodiment, in S2, the first mixture is subjected to ball milling treatment, the ball-to-material ratio is (4-6):1, the ball-to-material rotation speed is 300rpm-400rpm, and the ball milling time is 6h-8h.

[0039] Specifically, by controlling the ball-to-material ratio, ball-to-material rotation speed and ball milling time and other parameters in the ball milling treatment, the metal powder and modified graphene can be mixed uniformly and fully contacted. In a long time of ball milling, the metal powder may cause oxidation and agglomeration, at which time anhydrous ethanol anti-welding agent needs to be added.

[0040] As an embodiment, in S2, the second mixture is subjected to heat treatment, and the heat treatment includes vacuum high-temperature sintering of the second mixture.

[0041] As an embodiment, the sintering temperature is 570℃-700℃, and the sintering time is 20min-90min.

[0042] As an implementation, the sintering temperature is 600-650℃, and the sintering time is 30-60min.

[0043] Specifically, the heat treatment can ensure the sufficient combination of the metal elements and the modified graphene, and an aluminum alloy material with excellent performance is prepared.

[0044] The application is further described below through examples. Example 1

[0045] The application provides a heat-resistant high-strength aluminum alloy material, which comprises, in terms of mass percentage, 0.6wt% of Fe, 0.8wt% of Mg, 0.1wt% of Mn, 0.7wt% of Zn, 0.2wt% of Cr, 0.3wt% of Ti, 3.0wt% of Ni, 1.0wt% of Co, 0.8wt% of Sc, 2.5wt% of modified graphene, and the balance of Al.

[0046] The specific preparation steps are as follows:

[0047] S1, preparing modified graphene: 1L of 150g / L copper sulfate solution is configured as an electrolyte, two clean pure copper sheets with a length of 2cm, a width of 5cm and a thickness of 0.05cm are taken as a cathode and an anode for electroplating respectively, the relative distance between the cathode and the anode is 10cm, 2.0g of graphene is weighed and attached to the anode copper sheet, the direct current provided by the direct current power supply is 200mA, the first electroplating is carried out, and the electroplating reaction is carried out for 20h. After the reaction is completed, the cathode is taken out and the product obtained on the cathode copper sheet is washed with deionized water to obtain a copper / graphene composite material; then it is put into another electroplating tank containing 1L of 150g / L copper sulfate solution, the copper foil with the copper / graphene composite material is directly used as the cathode for the second electroplating, a pure copper sheet coated with 10.0g of nano-silicon with a length of 2cm, a width of 5cm and a thickness of 0.05cm is used as the anode, 10g of sodium dodecyl sulfate dispersant is added dropwise into the electrolyte to disperse the nano-silicon particles in the solution environment to form a stable suspension, and then the second electroplating is started, the direct current for the second electroplating is 100mA, the electroplating reaction is carried out for 20h, and the copper / graphene / silicon composite material, i.e., the modified graphene, is obtained at the cathode.

[0048] S2, preparing the aluminum alloy material: 2.5g of Fe, Mg, Mn, Zn, Cr, Ti, Ni, Co, Sc, Al and the modified graphene prepared in S1 are mixed according to the aforementioned proportions to obtain 100g of a first mixture, the first mixture is subjected to ball milling treatment, the ball-to-material ratio is 5:1, the ball-to-material rotation speed is 300rpm, the ball milling time is 8h, at the time of 2h of ball milling, anhydrous ethanol antiforgings are added to the first mixture, the amount of addition is 2ml, after the ball milling, a second mixture is obtained, then the second mixture is subjected to vacuum sintering for 60min, the sintering temperature is 600℃, and the aluminum alloy material is obtained. Example 2

[0049] The difference between this example and Example 1 is that the amount of 0.3wt% of Fe, 1.5wt% of Mg, 0.3wt% of Mn, 0.9wt% of Zn; 0.3wt% of Cr, 0.2wt% of Ti; 1.5wt% of Ni, 0.5wt% of Co, 0.3wt% of Sc, 3.6wt% of modified graphene. Example 3

[0050] The difference between this example and Example 1 is that the amount of 0.5wt% of Fe, 1.2wt% of Mg, 0.2wt% of Mn, 0.8wt% of Zn; 0.2wt% of Cr, 0.3wt% of Ti; 2.3wt% of Ni, 0.7wt% of Co, 0.5wt% of Sc, 1.2wt% of modified graphene.

[0051] Comparative Example 1

[0052] The difference between this example and Example 1 is that the amount of modified graphene is 0.1wt%.

[0053] Comparative Example 2

[0054] The difference between this example and Example 1 is that only the first electroplating operation is performed in S1, and the electroplating time is extended to 40h.

[0055] Comparative Example 3

[0056] The difference between this example and Example 1 is that graphene is used to replace the modified graphene in the aluminum alloy material, that is, the modified graphene is not prepared in S1, and the modified graphene is not added in S2, but graphene is selected to replace.

[0057] Performance test

[0058] The aluminum alloy material prepared in each of the above examples and comparative examples is subjected to the following tests. The test method is carried out according to the standard GB / T 228.1-2010 for room temperature test and according to the standard GB / T 4338-2006 for high temperature test. The mechanical properties of the aluminum alloy at room temperature and high temperature are tested, including tensile strength, yield strength and elongation after fracture. The yield strength is the critical stress at which the aluminum alloy begins to deform plastically. The tensile strength is the maximum bearing stress of the aluminum alloy. The elongation after fracture is the plastic deformation capacity of the aluminum alloy.

[0059] The test results are shown in Table 1.

[0060] Table 1

[0061]

[0062] It can be known from Comparative Examples 1-3 that the aluminum alloy material of Example 2 has improved mechanical properties and heat resistance due to the addition of a high value (3.6wt%) of modified graphene. The alloy formula and preparation process are optimal. The addition amount of modified graphene in the preparation process will affect the properties of the finally prepared aluminum alloy. It can be known from Comparative Example 1 that when the amount of modified graphene is 0.1wt%, the addition amount is much lower than the 2.5wt% defined in the present application, and the mechanical properties and heat resistance are also much lower than those of Example 1 of the present application. It can be known from Comparative Examples 1 and 2 that when the electrolyte in S1 is not subjected to secondary electroplating, the graphene in the copper / graphene composite material prepared is not coated with nano-silicon particles. The graphene in the copper / graphene composite material is in contact with the metal aluminum and is prone to interface reaction at high temperature to generate brittle aluminum-carbon phase, thereby reducing the mechanical properties and heat resistance of the aluminum alloy material and affecting the service life of the aluminum alloy. Even if the electroplating is continued, the graphene will not be completely covered by the copper that is not completely plated, and the graphene will still be in contact with the metal aluminum. The presence of nano-silicon particles not only avoids the direct contact between graphene and aluminum, but also increases the heat resistance and mechanical properties of the aluminum alloy and increases the service life of the aluminum alloy.

[0063] It can be known from Comparative Examples 1 and 3 that the graphene is used instead of the modified graphene in the aluminum alloy material, i.e. the graphene will be in contact with the metal aluminum and will also generate brittle aluminum-carbon phase, thereby reducing the mechanical properties and heat resistance of the aluminum alloy material and affecting the service life of the aluminum alloy.

[0064] In summary, the aluminum alloy material provided by the present application adds the copper / graphene / silicon composite material to the aluminum alloy, which can improve the heat resistance and mechanical properties of the aluminum alloy, and the copper / graphene / silicon composite material is coated with nano silicon particles and copper, so that the graphene cannot contact with the aluminum, thereby avoiding the interface reaction and the generation of brittle aluminum carbon phase at high temperature, and the silicon crystal has a high melting point of 1410 DEG C, high temperature resistance, high hardness, and is not chemically active at room temperature, so that it can be used to coat the copper / graphene, and further improve the heat resistance and mechanical properties of the aluminum alloy through the performance of the silicon crystal, thereby increasing the service life of the aluminum alloy. The copper / graphene / silicon composite material is prepared by the electroplating method, and the process is simple, the cost is low, and the industrial production is suitable.

[0065] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent ones. These modifications or replacements do not change the essence of the corresponding technical solutions, and should be included in the protection scope of the present application.

Claims

1. A heat-resistant high-strength aluminum alloy material, characterized by comprising, in mass %, The raw material components of the aluminum alloy material are 0.3-0.6wt% of Fe, 0.8-1.5wt% of Mg, 0.1-0.3wt% of Mn, 0.7-0.9wt% of Zn, 0.2-0.3wt% of Cr, 0.2-0.3wt% of Ti, 1.5-3wt% of Ni, 0.5-1.0wt% of Co, 0.3-0.8wt% of Sc, 1.2-3.6wt% of modified graphene, and the balance of Al; wherein the modified graphene is a copper / graphene / silicon composite material. The preparation method of the heat-resistant high-strength aluminum alloy material comprises the following preparation steps; S1, preparing modified graphene: configuring a divalent copper solution as an electrolyte, and preparing the modified graphene by using a two-time electroplating method under the action of direct current; wherein the specific operation of the electroplating method is: selecting two copper foils as cathode and anode respectively, coating graphene on the copper foil as anode, performing first-time electroplating, electrically treating the graphene, and generating copper / graphene composite material on the cathode; taking out the copper foil with the copper / graphene composite material and using it as the cathode for second-time electroplating, using the copper foil coated with nano-silicon as anode, electroplating the copper foil with the copper / graphene composite material, and preparing a copper / graphene / silicon composite material; S2, preparing an aluminum alloy material: mixing Fe, Mg, Mn, Zn, Cr, Ti, Ni, Co, Sc, Al and the modified graphene prepared in S1 according to the proportion, obtaining a first mixture, ball-milling the first mixture to obtain a second mixture, and then heat-treating the second mixture to obtain the aluminum alloy material.

2. A method of producing the heat-resistant high-strength aluminum alloy material according to claim 1, characterized by, Comprise the following preparation steps: S1, preparing modified graphene: configuring a divalent copper solution as an electrolyte, and preparing the modified graphene by using a two-time electroplating method under the action of direct current; wherein the specific operation of the electroplating method is: selecting two copper foils as cathode and anode respectively, coating graphene on the copper foil as anode, performing first-time electroplating, electrically treating the graphene, and generating copper / graphene composite material on the cathode; taking out the copper foil with the copper / graphene composite material and using it as the cathode for second-time electroplating, using the copper foil coated with nano-silicon as anode, electroplating the copper foil with the copper / graphene composite material, and preparing a copper / graphene / silicon composite material; S2, preparing an aluminum alloy material: mixing Fe, Mg, Mn, Zn, Cr, Ti, Ni, Co, Sc, Al and the modified graphene prepared in S1 according to the proportion, obtaining a first mixture, ball-milling the first mixture to obtain a second mixture, and then heat-treating the second mixture to obtain the aluminum alloy material.

3. The method of producing a heat-resistant high-strength aluminum alloy material according to claim 2, characterized by, In the S1, the surface area and thickness of the copper foil used as anode in the two-time electroplating method are consistent.

4. The method of producing a heat-resistant high-strength aluminum alloy material according to claim 2, characterized by, In the S1, the divalent copper solution in the electrolyte is a copper sulfate solution or a copper pyrophosphate solution, and / or the concentration of the divalent copper solution is 30g / L-210g / L.

5. The method of producing a heat-resistant high-strength aluminum alloy material according to claim 2, characterized by, In the S1, the mass ratio of the nano-silicon particles to the graphene is (3-8):

1.

6. The method of producing a heat-resistant high-strength aluminum alloy material according to claim 2, characterized by, The S1, the direct current is 50mA-200mA.

7. The method of producing a heat-resistant high-strength aluminum alloy material according to claim 2, characterized by, The S1, the electroplating method is 8h-20h.

8. The method of producing a heat-resistant high-strength aluminum alloy material according to claim 2, characterized by, The S2, the first mixture is ball milled, the ball to material ratio (3-8):1, the ball milling speed is 200rpm-500rpm, the ball milling time is 5h-10h.

9. The method of producing a heat-resistant high-strength aluminum alloy material according to claim 2, characterized by, The S2, the second mixture is heat treated, the heat treatment includes vacuum high temperature sintering of the second mixture.

10. The method of producing a heat-resistant high-strength aluminum alloy material according to claim 9, characterized by, The sintering temperature is 570℃-700℃, the sintering time is 20min-90min.

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