High modulus aluminum-based composite material for aviation, transportation tool and preparation method

Abstract

The present invention belongs to the technical field of aluminum matrix composites, and relates to a high-modulus aluminum matrix composite for aviation, a transportation vehicle and a preparation method. The aluminum matrix composite, by weight percentage, comprises 0.5% to 2.0% of a modulus improvement phase and the balance of 7050 aluminum alloy; wherein, the 7050 aluminum alloy comprises the following elements in mass percentage: Mg: 1.6% to 3%, Zn: 5.0% to 6.5%, Cu: 1.5% to 2.6%, Mn: 0.05% to 0.1%, the balance being Al and other inevitable impurities including Fe and Si, and the impurities ≤ 0.45%; the modulus improvement phase comprises two or more of graphene, carbon nanotubes and silicon nitride. The cabin section for an aviation transportation vehicle made of the aluminum matrix composite has a tensile strength R m reaching ≥ 600 MPa or more (20% higher than 7050), and a proof strength R P reaching ≥ 500 MPa (10% higher than 7050), an elastic modulus E reaching 85 to 101 GPa (more than 30% higher than 7050), and an elongation after fracture reaching 8%, showing comprehensive mechanical properties of high strength, high toughness and high modulus.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum-based composite materials, and in particular relates to a high-modulus aluminum-based composite material for aviation, a transportation vehicle and a preparation method. Background Art

[0002] Aluminum alloy is a general term for alloys based on aluminum. The main alloying elements are copper, silicon, magnesium, zinc, manganese, and secondary alloying elements such as nickel, iron, titanium, chromium, and lithium. Aluminum alloys have been widely used in aviation, aerospace, automobile, machinery manufacturing, shipbuilding and chemical industries. Aluminum alloys have low density, high specific strength, good plasticity, can be processed into various profiles, and have excellent electrical conductivity, thermal conductivity and corrosion resistance. Therefore, they have been widely used in aviation transportation vehicles, especially aluminum alloys with a yield strength of more than 500MPa. The most common one is the super-hard aluminum with a grade of 7 series. This series of aluminum alloys was originally developed in the context of aerospace applications. At present, it has developed into the main structural material of military and civilian aircraft in various countries in the world, accounting for 70-80% of the proportion in aircraft structural parts, and has replaced expensive titanium alloys in many fields, becoming an indispensable and important lightweight structural material. With the continuous development of modern aerospace, nuclear industry, and transportation industry, higher requirements are put forward for the comprehensive performance of structural parts. The new generation of ultra-high-strength aluminum alloys with light weight, high strength, high toughness and high modulus are undoubtedly the first choice. For example, 7050 high-strength aluminum alloy has high strength and good fracture toughness, and is often used in aircraft fuselage frames, wing skins, bulkheads, girders, stiffeners, brackets, landing gear support components, etc. Its tensile strength can reach more than 500MPa, but its elastic modulus is generally about 72GPa. If the load-bearing parts of modern aviation transportation structures are to be further reduced in weight, in addition to further improving tensile strength and yield strength, they also need to improve their deformation resistance, and it is undoubtedly necessary to improve the elastic modulus.

[0003] The main methods for improving the elastic modulus of aluminum alloys are alloying and compounding. Among them, the alloying method mainly prepares aluminum-lithium alloys by adding lithium (Li). For example, Chinese patent document CN105648283A discloses a low-density, high-rigidity cast aluminum-lithium alloy and its preparation method, with an elastic modulus of not less than 78GPa; the compounding method mainly adds SiC, Ti 2 B particles to prepare aluminum-based composite materials, such as Chinese patent document CN106834833A discloses a high modulus, ultra-high strength TiB 2A particle-reinforced Al-Zn-Mg-Cu composite material and a preparation method thereof can obtain a high-modulus aluminum alloy with an elastic modulus of not less than 82 GPa; Chinese patent document CN109868397A discloses a high-modulus, ultra-high-strength aluminum alloy material: Mg: 2.5-6.0%, one or two of the rare earth elements Ce and La: 0.01-1.2%, one or two or more of Mn, Cr, and V: 2.0-10.0%, the remainder is Al, impurities ≤0.45%, the elastic modulus is about 85-92 GPa, the tensile strength is 320-390 MPa, the yield strength is 200-220 MPa, and the elongation is 6-8.5%.

[0004] The above-mentioned method of melting and casting by adding alloy elements or the method of producing aluminum-based composite materials by powder metallurgy cannot fully meet the requirements of high strength, high toughness and high modulus for aerospace, and its static strength and elastic modulus need to be further improved. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention aims to provide a high modulus aluminum-based composite material for aviation, a transportation vehicle and a preparation method. The key technical problem to be solved by the present invention is to optimize the alloy composition, use 7050 aluminum alloy as the base material, add any two or more modulus-improving phases of graphene, carbon nanotubes and silicon nitride in trace amounts, coordinate Al, Zn, Mg, Cu, Mn and impurities Fe and Si as components, and obtain a structural load-bearing part for aviation transportation vehicles composed of a low-cost high modulus aluminum-based composite material by ball milling with a required heating of no more than 500°C, vacuum hot isostatic pressing, milling, cleaning and isothermal forging.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, a high modulus aluminum-based composite material for aviation includes, by weight percentage, 0.5% to 2.0% of a modulus-improving phase and the remainder of 7050 aluminum alloy; wherein:

[0008] The 7050 aluminum alloy includes the following elements in mass percentage: Mg: 1.6% to 3%, Zn: 5.0% to 6.5%, Cu: 1.5% to 2.6%, Mn: 0.05% to 0.1%, and the balance is Al and other inevitable impurities including Fe and Si, and the impurities are ≤ 0.45%;

[0009] The modulus-improving phase includes two or more of graphene, carbon nanotubes and silicon nitride.

[0010] Furthermore, the modulus-improving phase consists of graphene, carbon nanotubes and silicon nitride.

[0011] Furthermore, the impurities include: Fe: 0.05% to 0.15%, Si: 0.05% to 0.15%.

[0012] Furthermore, the graphene has a particle size of 5-8 μm and a layer number of no more than 3 layers.

[0013] Furthermore, the particle size of the silicon nitride is 3 to 5 μm.

[0014] Furthermore, the elastic modulus of the high modulus aluminum-based composite material for aviation is 85 to 101 GPa.

[0015] In a second aspect, an aviation transportation vehicle comprises the structural load-bearing member for aviation transportation vehicle, wherein the structural load-bearing member for aviation transportation vehicle is made of the high modulus aluminum-based composite material for aviation.

[0016] Furthermore, the structural load-bearing member for aviation transportation vehicles is a cabin section.

[0017] In a third aspect, a method for preparing the high modulus aluminum-based composite material for aviation use includes preparing alloy powder of the 7050 aluminum alloy, and preparing an aluminum-based composite material composed of the alloy powder and the modulus-improving phase;

[0018] The alloy powder preparation includes the steps of baking, smelting, refining and atomizing powder making;

[0019] The preparation of the aluminum-based composite material includes the steps of ball milling, hot isostatic pressing, isothermal forging and solution treatment; the temperature of the heating treatment involved in the preparation of the aluminum-based composite material does not exceed 500°C.

[0020] Furthermore, the preparation method comprises the following steps:

[0021] (1) Baking: preheating and keeping the Al, Zn, Mg, Mn and Cu raw materials separately;

[0022] (2) Melting: During the melting process, at the first temperature, the Al and Cu raw materials obtained in (1) are added and stirred until they are completely melted; when the temperature of the melt is raised to the second temperature, the Zn raw material and the Mn raw material obtained in (1) are added until they are completely melted; when the temperature of the melt is lowered to the third temperature, the Mg raw material obtained in (1) is added and melted, and pressed into the melt and stirred until it is completely melted;

[0023] (3) Refining: The melt is heated to the refining temperature, and a refining agent is added for refining; the scum is skimmed off and the melt is allowed to stand; a covering agent is added to the melt and stirred in a protective atmosphere; finally, a refiner is added for refining, and the scum is skimmed off to obtain a 7050 aluminum alloy melt;

[0024] (4) Powdering: The 7050 aluminum alloy melt is heated to a powdering temperature and atomized to obtain the alloy powder;

[0025] (5) hot isostatic pressing of a blank: adding at least two of the modulus-improving phases to the alloy powder, introducing liquid nitrogen into the powder for ball milling and mixing; hot isostatic pressing the mixed ingredients to obtain an aluminum-based composite blank of a 7050 aluminum alloy reinforced with the modulus-improving phase;

[0026] (6) Isothermal forging: milling and cleaning the blank obtained in step (5), and then isothermal forging to obtain a forging blank;

[0027] (7) Solution treatment: The forging blank obtained in step (6) is subjected to heating, heat preservation, water cooling and aging treatment to obtain the aluminum-based composite material.

[0028] Furthermore, the Al, Zn and Mg raw materials are selected from industrial pure aluminum, industrial pure zinc and industrial pure magnesium respectively.

[0029] Furthermore, the Cu raw material is selected from aluminum-copper master alloy.

[0030] Furthermore, the Mn raw material is selected from aluminum-manganese master alloy.

[0031] Furthermore, the preheating and heat preservation temperature is 200-300° C., and the time is 0.5-2 hours.

[0032] Furthermore, the first temperature is 200-300°C.

[0033] Furthermore, the second temperature is 740-800°C.

[0034] Furthermore, the third temperature is 720-740°C.

[0035] Furthermore, the refining temperature is 735-745°C.

[0036] Furthermore, in the refining step (3), the refining agent is added for refining for 10 to 20 minutes.

[0037] Furthermore, a covering agent is added to the melt in a protective atmosphere N 2 Stir in air for 5 to 10 minutes.

[0038] Furthermore, the covering agent includes MgCl 2 A mixture of KCl with a mass ratio of 3:2.

[0039] Furthermore, the added amount of the covering agent is 0.2% to 1.5% of the total mass of the melt.

[0040] Furthermore, the refiner comprises an aluminum-titanium-boron master alloy.

[0041] Furthermore, in the step (4) of powder making, the powder making temperature is 825-835°C.

[0042] Furthermore, the atomization pressure is 0.5-1.5 MPa.

[0043] Furthermore, the atomizing gas is N 2 .

[0044] Furthermore, the particle size of the alloy powder is 5 to 20 μm.

[0045] Furthermore, in step (5) of hot isostatic pressing the blank, the ball milling time is 3 to 5 hours.

[0046] Furthermore, the heating rate of the hot isostatic pressing is 1-3°C / min.

[0047] Furthermore, the holding temperature of the hot isostatic pressing is 470-490°C.

[0048] Furthermore, the pressing pressure of the hot isostatic pressing is 35-45 MPa.

[0049] Furthermore, the heat preservation and pressure holding time of the hot isostatic pressing is 3 to 5 hours.

[0050] Furthermore, in step (7) solution treatment, the heating and heat preservation temperature is 450-500° C. and the time is 8-30 hours.

[0051] Furthermore, the water temperature of the water cooling is 0-80°C.

[0052] Furthermore, the aging treatment is carried out at a temperature of 100 to 225° C. for 8 to 25 hours.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] (1) The aluminum-based composite material of the present invention uses 7050 aluminum alloy as a substrate, and adds a trace amount of any two or more of graphene, carbon nanotubes, and silicon nitride as modulus-improving phases, and coordinates Al, Zn, Mg, Cu, Mn, and impurities Fe and Si as components to optimize the alloy composition. The composite phases are well compatible and show comprehensive mechanical properties of high strength, high toughness, and high modulus, and are suitable for the aerospace field.

[0055] (2) The preparation method of aluminum-based composite materials of the present invention has a simple process flow and stable process parameters. In a vacuum hot isostatic pressing furnace, the powder is kept warm and pressurized to form a blank in one step, which reduces the process steps and saves time and cost. Among metal-based composite materials, the C / Al composite material is the most sensitive to the interface. Generally, the composite interface between C and Al will generate more Al at 500°C.4 C 3 reactants, the process of the present invention better prevents Al 4 C 3 Generated to ensure product quality.

[0056] (3) The high modulus aluminum-based composite material for aviation of the present invention has excellent quality, and the tensile strength R of the load-bearing parts of the aviation transportation vehicle structure made of it is m Reach ≥600MPa (20% higher than 7050), specify non-proportional elongation strength R P It reaches ≥500MPa (10% higher than 7050), elastic modulus E reaches 85-101GPa (30% higher than 7050), and elongation after break reaches 8%, showing comprehensive mechanical properties of high strength, high toughness and high modulus. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a schematic diagram of a structural load-bearing member (cabin section) of an aviation transportation vehicle made of the aluminum-based composite material of the present invention. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The embodiments of the present invention are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and processes are given, but the protection scope of the present invention is not limited to the following embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0059] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0060] In the present invention, unless otherwise specified and / or described, all numerical values ​​involving the amount of components are "mass or mass percentage" from beginning to end. The process parameters without specific conditions in the following examples are usually based on conventional conditions. The raw materials described in the following examples can all be obtained from public commercial channels.

[0061] According to a first aspect of the present invention, a high modulus aluminum-based composite material for aviation includes, by weight percentage, 0.5% to 2.0% of a modulus-improving phase and the remainder of 7050 aluminum alloy; wherein:

[0062] The 7050 aluminum alloy includes the following elements in mass percentage: Mg: 1.6% to 3%, Zn: 5.0% to 6.5%, Cu: 1.5% to 2.6%, Mn: 0.05% to 0.1%, and the balance is Al and other inevitable impurities including Fe and Si, and the impurities are ≤ 0.45%;

[0063] The modulus-improving phase includes two or more of graphene, carbon nanotubes, and silicon nitride.

[0064] The aluminum-based composite material of the present invention uses 7050 aluminum alloy as a substrate, adds any two or more of graphene, carbon nanotubes and silicon nitride in trace amounts as modulus-improving phases, and coordinates Al, Zn, Mg, Cu, Mn and impurities Fe and Si as components to optimize alloy composition. When the modulus-improving phase is 0.5 to 2.0% (wt) of at least two of the graphene, carbon nanotubes and silicon nitride, the aluminum-based composite material has good compatibility among various phases and excellent quality, exhibits comprehensive mechanical properties of high strength, high toughness and high modulus, and is suitable for the field of aerospace.

[0065] Generally, in order to further improve the tensile strength, yield strength and elongation of aluminum alloys, various reinforcing phases are added to the aluminum matrix to meet the high strength and toughness requirements of aerospace. Graphene is regarded as an ideal reinforcing and toughening material for lightweight structural composites due to its superb mechanical properties and perfect one-dimensional structure. Theoretical studies have shown that the tensile strength of graphene is 125GPa and the Young's modulus is about 42N / m 2 , is the strongest material known so far. Composite materials with graphene as the reinforcement phase have excellent properties such as light weight, high strength and wear resistance. 3 N 4 ) is a covalent bond compound with high bonding strength between Si-N, and the room temperature strength can reach 700-1000MPa. It has excellent properties such as high strength, wear resistance, corrosion resistance, and oxidation resistance. It has been used in many fields as a reinforcement phase. During the research and development process, the inventor creatively used conventional reinforcement phase materials graphene, carbon nanotubes, and silicon nitride as elastic modulus improvement phases, and found that any two or more of them have good addition, compatibility, and elastic modulus improvement effects in 7050 aluminum alloy, and the elastic modulus of the resulting composite material can reach 85-101GPa.

[0066] In the 7050 aluminum alloy of the present invention, the Zn element is 5.0% to 6.5% of the total mass of the aluminum alloy. The Zn content should not be too high or too low. If it is too high, the cracking tendency of the alloy will increase, and if it is too low, the precipitation strengthening effect will be reduced and the strength will be reduced. As an optional embodiment, the mass percentage of the Zn element can be typically but not limitatively selected as 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, 6.1%, 6.2%, 6.3%, 6.4%, etc. of the total mass of the aluminum alloy. The Cu element accounts for 1.5% to 2.6% of the total mass of the aluminum alloy. As an optional embodiment, the mass percentage of the Cu element can be typically but not limitatively selected as 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5% or the like of the total mass of the aluminum alloy.

[0067] Meanwhile, as an optional embodiment, the mass percentage of the Mg element can be typically but not limitedly selected as 1.7%, 1.9%, 2.1%, 2.3%, 2.5%, 2.7%, 2.9% etc. of the total mass of the aluminum alloy; the mass percentage of the Mn element can be typically but not limitedly selected as 0.06%, 0.07%, 0.08%, 0.09% etc. of the total mass of the aluminum alloy. The total mass percentage of other unavoidable impurity elements can be typically but not limitedly selected as 0.45%, 0.40%, 0.35%, 0.30%, 0.25%, 0.20%, 0.15%, 0.10%, 0.05% etc. of the total mass of the aluminum alloy. Preferably, among the impurities, the mass percentage of Fe element can be typically but not limitedly selected as 0.06%, 0.08%, 0.10%, 0.12%, 0.14% etc. of the total mass of the aluminum alloy, and the mass percentage of Si element can be typically but not limitedly selected as 0.06%, 0.08%, 0.10%, 0.12%, 0.14% etc. of the total mass of the aluminum alloy.

[0068] The modulus improvement phase of the present invention: graphene particle size is 5-8μm, and the number of layers does not exceed 3; carbon nanotubes; silicon nitride particle size is 3-5μm; the total content of any two or more of the above accounts for 0.5% to 2.0% of the mass of the aluminum-based composite material, and the content should not be too high or too low. If it is too high, the plasticity of the alloy will be reduced, and if it is too low, the strength and elastic modulus will be reduced. As an optional embodiment, the particle size of graphene can be typically but not limitedly selected as 5.1μm, 5.3μm, 5.5μm, 5.7μm, 5.9μm, 6.1μm, 6.3μm, 6.5μm, 6.7μm, 6.9μm, 7.1μm, 7.3μm, 7.5μm, 7.7μm, 7.9μm, etc., and the number of graphene layers can be typically but not limitedly selected as 1 layer, 2 layers, 3 layers and any combination. If there are too many layers, the particle size will be too large; The particle size of silicon nitride can be typically but not limitedly selected as 3.1 μm, 3.3 μm, 3.5 μm, 3.7 μm, 3.9 μm, 4.1 μm, 4.3 μm, 4.5 μm, 4.7 μm, 4.9 μm, etc.; the total content of any two or more of the graphene, carbon nanotubes and silicon nitride can be typically but not limitedly selected as 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, etc. of the mass of the aluminum-based composite material. Preferably, the modulus-improving phase consists of graphene, carbon nanotubes and silicon nitride.

[0069] According to a second aspect of the present invention, an aviation transportation vehicle comprises the structural load-bearing member for aviation transportation vehicle, wherein the structural load-bearing member for aviation transportation vehicle is made of the high modulus aluminum-based composite material for aviation.

[0070] As an optional implementation of the aviation transportation vehicle of the present invention, the structural load-bearing member for the aviation transportation vehicle is a cabin section.

[0071] According to a third aspect of the present invention, a method for preparing the aluminum-based composite material comprises preparing alloy powder of the 7050 aluminum alloy, and preparing an aluminum-based composite material composed of the alloy powder and the modulus-improving phase;

[0072] The alloy powder preparation includes the steps of baking, smelting, refining and atomizing powder making;

[0073] The preparation of the aluminum-based composite material includes the steps of ball milling, hot isostatic pressing, isothermal forging and solution treatment; the temperature of the heating treatment involved in the preparation of the aluminum-based composite material does not exceed 500°C.

[0074] The process of the present invention is simple. In a vacuum hot isostatic pressing furnace, the powder is kept warm and pressurized to form a blank in one step, which reduces the process steps and saves time and cost. In addition, when preparing composite materials, it is found that among metal-based composite materials, C / Al composite materials are most sensitive to the interface. Generally, the composite interface of C and Al will generate more Al at 500°C. 4 C 3 reactants, in the process of the present invention, the relevant heating temperature is controlled not to exceed 500°C during the composite preparation, which better prevents Al 4 C 3 Generated to ensure product quality.

[0075] In fact, the preparation method of the aluminum-based composite material is the same as the preparation method of the structural load-bearing member for aviation transportation vehicles, and the preparation method of the structural load-bearing member for aviation transportation vehicles includes preparing the alloy powder of the 7050 aluminum alloy, and compounding the alloy powder with the modulus improvement phase to prepare the structural load-bearing member for aviation transportation vehicles;

[0076] The alloy powder preparation includes the steps of baking, smelting, refining and atomizing powder making;

[0077] The preparation of the structural load-bearing parts for aviation transportation vehicles includes the steps of ball milling mixing of the alloy powder and the modulus-improving phase, hot isostatic pressing, isothermal forging and solution treatment, wherein the temperature involved in the heating treatment does not exceed 500°C.

[0078] More specifically:

[0079] The method for preparing the aluminum-based composite material or the structural load-bearing member for aviation transportation vehicles comprises the following steps:

[0080] (1) Baking: preheating and keeping the Al, Zn, Mg, Mn and Cu raw materials separately;

[0081] (2) Melting: During the melting process, at the first temperature, the Al and Cu raw materials obtained in (1) are added and stirred until they are completely melted; when the temperature of the melt is raised to the second temperature, the Zn raw material and the Mn raw material obtained in (1) are added until they are completely melted; when the temperature of the melt is lowered to the third temperature, the Mg raw material obtained in (1) is added and melted, and pressed into the melt and stirred until it is completely melted;

[0082] (3) Refining: The melt is heated to the refining temperature, and a refining agent is added for refining; the scum is skimmed off and the melt is allowed to stand; a covering agent is added to the melt and stirred in a protective atmosphere; finally, a refiner is added for refining, and the scum is skimmed off to obtain a 7050 aluminum alloy melt;

[0083] (4) Powdering: The 7050 aluminum alloy melt is heated to a powdering temperature and atomized to obtain the alloy powder;

[0084] (5) hot isostatic pressing of a blank: adding at least two of the modulus-improving phases to the alloy powder, introducing liquid nitrogen into the powder for ball milling and mixing; hot isostatic pressing the mixed ingredients to obtain an aluminum-based composite blank of a 7050 aluminum alloy reinforced with the modulus-improving phase;

[0085] (6) Isothermal forging: milling and cleaning the blank obtained in step (5), and then isothermal forging to obtain a forging blank;

[0086] (7) Solution treatment: The forging blank obtained in step (6) is subjected to heating, heat preservation, water cooling and aging treatment to obtain the aluminum-based composite material / the structural load-bearing component for aviation transportation vehicles.

[0087] As an optional implementation of the preparation method of the present invention, the Al, Zn and Mg are respectively selected from industrial pure aluminum, industrial pure zinc and industrial pure magnesium; and / or, the Cu is added in the form of an aluminum-copper master alloy; and / or, the Mn is added in the form of an aluminum-manganese master alloy.

[0088] As an optional embodiment of the preparation method of the present invention, the graphene particle size is 5-8μm (specifically 5.1μm, 5.3μm, 5.5μm, 5.7μm, 5.9μm, 6.1μm, 6.3μm, 6.5μm, 6.7μm, 6.9μm, 7.1μm, 7.3μm, 7.5μm, 7.7μm, 7.9μm), and the number of graphene layers does not exceed 3 layers (specifically 1 layer, 2 layers, 3 layers and any combination).

[0089] As an optional embodiment of the preparation method of the present invention, the silicon nitride has a particle size of 3 to 5 μm (specifically 3.1 μm, 3.3 μm, 3.5 μm, 3.7 μm, 3.9 μm, 4.1 μm, 4.3 μm, 4.5 μm, 4.7 μm, 4.9 μm).

[0090] As an optional embodiment of the preparation method of the present invention, the preheating and insulation temperature is 200-300°C (specifically 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C), and the time is 0.5-2h (specifically 0.6h, 0.8h, 1h, 1.2h, 1.4h, 1.6h, 1.8h).

[0091] As an optional embodiment of the preparation method of the present invention, the first temperature is 200-300°C (specifically 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C).

[0092] As an optional implementation of the preparation method of the present invention, the second temperature is 740-800°C (specifically 750°C, 760°C, 770°C, 780°C, 790°C).

[0093] As an optional implementation mode of the preparation method of the present invention, the third temperature is 720-740°C (specifically 721°C, 725°C, 727°C, 730°C, 733°C, 736°C, 738°C).

[0094] As an optional implementation mode of the preparation method of the present invention, the refining temperature is 735-745°C (specifically 736°C, 737°C, 738°C, 739°C, 740°C, 741°C, 742°C, 743°C, 744°C).

[0095] As an optional implementation of the preparation method of the present invention, in the refining step (3), the refining agent is added for refining for 10 to 20 minutes (specifically 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, and 19 minutes).

[0096] As an optional embodiment of the preparation method of the present invention, a covering agent is added to the melt, and a protective atmosphere N 2 Stir in air for 5 to 10 minutes (specifically 6 minutes, 7 minutes, 8 minutes, 9 minutes).

[0097] As an optional embodiment of the preparation method of the present invention, the covering agent is MgCl 2 A mixture of KCl with a mass ratio of 3:2.

[0098] As an optional embodiment of the preparation method of the present invention, the amount of the covering agent added is 0.2% to 1.5% of the total mass of the melt (specifically 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%).

[0099] As an optional implementation of the preparation method of the present invention, the refiner is an aluminum-titanium-boron master alloy.

[0100] As an optional embodiment of the preparation method of the present invention, in the powder making step (4), the powder making temperature is 825-835°C (specifically 826°C, 827°C, 828°C, 829°C, 830°C, 831°C, 832°C, 833°C, 834°C).

[0101] As an optional embodiment of the preparation method of the present invention, the atomization pressure is 0.5-1.5 MPa (specifically 0.6 MPa, 0.8 MPa, 1.0 MPa, 1.2 MPa, 1.4 MPa). And / or, the atomization gas is N 2 .

[0102] As an optional embodiment of the preparation method of the present invention, the particle size of the alloy powder is 5 to 20 μm (specifically 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm).

[0103] In the above technical solution, the particle size of the alloy powder is controlled within the above range, which can make the performance of the composite material better.

[0104] As an optional implementation mode of the preparation method of the present invention, in the step (5) of hot isostatic pressing of the billet, the ball milling time is 3 to 5 h (specifically 3.2 h, 3.5 h, 3.7 h, 4 h, 4.2 h, 4.5 h, 4.7 h).

[0105] As an optional implementation method of the preparation method of the present invention, the heating rate of the hot isostatic pressing is 1 to 3°C / min (specifically 1.2°C / min, 1.5°C / min, 1.7°C / min, 2°C / min, 2.2°C / min, 2.5°C / min, 2.7°C / min).

[0106] As an optional implementation mode of the preparation method of the present invention, the holding temperature of the hot isostatic pressing is 470-490°C (specifically 471°C, 473°C, 475°C, 477°C, 479°C, 481°C, 483°C, 485°C, 487°C, 489°C).

[0107] As an optional implementation of the preparation method of the present invention, the pressing pressure of the hot isostatic pressing is 35-45 MPa (specifically 36 MPa, 38 MPa, 40 MPa, 42 MPa, 44 MPa).

[0108] As an optional implementation mode of the preparation method of the present invention, the heat preservation and pressure holding time of the hot isostatic pressing is 3 to 5 hours (specifically 3.2 hours, 3.5 hours, 3.7 hours, 4 hours, 4.2 hours, 4.5 hours, and 4.7 hours).

[0109] As an optional embodiment of the preparation method of the present invention, in the step (7) solution treatment, the heating and insulation temperature is 450-500°C (specifically 455°C, 460°C, 465°C, 470°C, 475°C, 480°C, 485°C, 490°C, 495°C), and the time is 8-30h (specifically 9h, 11h, 13h, 15h, 17h, 19h, 21h, 23h, 25h, 27h, 29h).

[0110] As an optional implementation mode of the preparation method of the present invention, the water temperature of the water cooling is 0-80°C (specifically 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C).

[0111] As an optional embodiment of the preparation method of the present invention, the aging treatment is to keep warm at 100-225°C (specifically 110°C, 130°C, 150°C, 170°C, 190°C, 210°C) for 8-25h (specifically 9h, 11h, 13h, 15h, 17h, 19h, 21h, 23h).

[0112] The present invention will be further described below by means of specific examples.

[0113] Embodiment 1:

[0114] The high modulus aluminum-based composite material for aviation provided in this embodiment includes, by weight percentage: modulus-improving phase: 1.0% graphene, 1.0% carbon nanotubes and 0.0% silicon nitride, and substrate: 98% 7050 aluminum alloy; the 7050 aluminum alloy is composed of the following elements by mass percentage: Mg: 2.6%, Zn: 5.0%, Cu: 2.0%, Mn: 0.07%, and unavoidable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The preparation method steps are as follows:

[0115] (1) Melting the alloy to obtain an aluminum alloy melt.

[0116] Melting steps: (a) baking, preheating the raw materials at 250°C for 2 hours; (b) melting, setting the melting temperature of the melting furnace to 800°C, when the furnace temperature rises to 300°C, adding industrial pure aluminum and aluminum-copper master alloy until they are completely melted and stirred evenly; heating the melt to 760°C, adding industrial pure zinc and aluminum-manganese master alloy, stirring evenly until they are completely melted; when the melt temperature drops to 720°C, adding industrial pure magnesium, melting, stirring evenly until they are completely melted; (c) refining, when the melt temperature reaches 740°C, adding a refining agent for refining for 10 to 20 minutes, scraping off the surface scum after refining, and letting the melt stand; (d) degassing: when the melt temperature rises to 730°C, adding 60% MgCl 2+40% KCl composition is used as a covering agent, nitrogen is filled and stirred for 5 to 10 minutes; (e) refinement: aluminum titanium boron is added, and after refinement, the scum on the surface of the melt is scraped off to obtain a 7050 aluminum alloy melt.

[0117] (2) Powder making: Powder making is done on the spray forming equipment. After the alloy is refined, it is heated to 1103K and flows into the preheated silicon carbide crucible through the sealed runner. The molten liquid in the crucible flows out through the graphite nozzle with an inner aperture d of 3 to 5 mm and is atomized in the atomizer. The N 2 The pressure is 1.0 MPa; the particle size of the prepared alloy powder is 5 to 20 μm.

[0118] (3) Hot isostatic pressing: Add 1% by weight of graphene (5-8 μm, 1 to 3 layers), 1.0% by weight of carbon nanotubes, and 0.0% by weight of silicon nitride (3 to 5 μm) to the prepared alloy powder; put the prepared powder into a ball mill and introduce liquid nitrogen for ball milling for 4 hours; put the mixed ingredients into an aluminum package and evacuate to 10-1 Pa; put the material into a hot isostatic pressing device and heat it to 480°C at a rate of 1 to 3°C / min, then press it at a pressure of 40 MPa under insulation for 4 hours to obtain an aluminum-based composite material blank.

[0119] (4) Isothermal forging: The blank is milled and cleaned, and then is isothermally forged at 480°C in a die to produce a cabin section forging blank for aviation transportation vehicles made of aluminum-based composite materials.

[0120] (5) Solution treatment: The forging blank is kept at 480°C for 10 hours, water-cooled at 60°C, and kept at 180°C for 10 hours for aging treatment to obtain an aviation transportation vehicle cabin section (such as Figure 1 shown).

[0121] Embodiment 2:

[0122] The difference between Example 2 and Example 1 is that the aluminum-based composite material of Example 2 includes, by weight percentage: modulus-improving phase: graphene 1.0%, carbon nanotubes 0.0%, silicon nitride 1.0%, and substrate: 7050 aluminum alloy 98%; the 7050 aluminum alloy is composed of the following elements by mass percentage: Mg: 2.6%, Zn: 5.0%, Cu: 2.0%, Mn: 0.07%, and unavoidable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0123] Embodiment 3:

[0124] The difference between Example 3 and Example 1 is that the aluminum-based composite material of Example 3 includes, by weight percentage: modulus-improving phase: 0.0% graphene, 1.0% carbon nanotubes, 1.0% silicon nitride, and substrate: 98% 7050 aluminum alloy; the 7050 aluminum alloy is composed of the following elements by mass percentage: Mg: 2.6%, Zn: 5.0%, Cu: 2.0%, Mn: 0.07%, and unavoidable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0125] Embodiment 4:

[0126] The difference between Example 4 and Example 1 is that the aluminum-based composite material of Example 4 includes, by weight percentage: modulus-improving phase: 0.5% graphene, 0.5% carbon nanotubes, 0.5% silicon nitride, and substrate: 98.5% 7050 aluminum alloy; the 7050 aluminum alloy is composed of the following elements by mass percentage: Mg: 2.6%, Zn: 5.0%, Cu: 2.0%, Mn: 0.07%, and unavoidable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0127] Embodiment 5:

[0128] The difference between Example 5 and Example 1 is that the aluminum-based composite material of Example 5 includes, by weight percentage: modulus-improving phase: 1.0% graphene, 0.5% carbon nanotubes, 0.5% silicon nitride, and substrate: 98% 7050 aluminum alloy; the 7050 aluminum alloy is composed of the following elements by mass percentage: Mg: 2.6%, Zn: 5.0%, Cu: 2.0%, Mn: 0.07%, and unavoidable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0129] Comparative Example 1:

[0130] Comparative Example 1 is different from Example 1 in that no modulus-improving phase is added, and the material is 100% 7050 aluminum alloy, and the following elements are composed by mass percentage: Mg: 2.0%, Zn: 5.0%, Cu: 2.0%, Mn: 0.07%, and inevitable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0131] Comparative Example 2:

[0132] Comparative Example 2 is different from Example 1 in that no modulus-improving phase is added, and the material is 100% 7050 aluminum alloy, and the following elements are composed by mass percentage: Mg: 2.3%, Zn: 5.5%, Cu: 2.3%, Mn: 0.07%, and inevitable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0133] Comparative Example 3:

[0134] Comparative Example 3 is different from Example 1 in that no modulus-improving phase is added, and the material is 100% 7050 aluminum alloy, and the following elements are composed by mass percentage: Mg: 2.6%, Zn: 6.0%, Cu: 2.5%, Mn: 0.07%, and inevitable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0135] Comparative Example 4:

[0136] Comparative Example 4 is different from Example 1 in that only graphene is added. The aluminum-based composite material of Comparative Example 4 includes, by weight percentage: modulus-improving phase: 1.0% graphene, 0.0% carbon nanotubes and 0.0% silicon nitride, and substrate: 99% 7050 aluminum alloy; the 7050 aluminum alloy is composed of the following elements by mass percentage: Mg: 2.6%, Zn: 5.0%, Cu: 2.0%, Mn: 0.07%, and unavoidable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0137] Comparative Example 5:

[0138] Comparative Example 5 is different from Example 1 in that only carbon nanotubes are added. The aluminum-based composite material of Comparative Example 5 includes, by weight percentage: modulus-improving phase: 0.0% graphene, 1.0% carbon nanotubes and 0.0% silicon nitride, and substrate: 99% 7050 aluminum alloy; the 7050 aluminum alloy is composed of the following elements by mass percentage: Mg: 2.6%, Zn: 5.0%, Cu: 2.0%, Mn: 0.07%, and inevitable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0139] Comparative Example 6:

[0140] Comparative Example 6 is different from Example 1 in that only silicon nitride is added. The aluminum-based composite material of Comparative Example 6 includes, by weight percentage: modulus-improving phase: 0.0% graphene, 0.0% carbon nanotubes and 1.0% silicon nitride, and substrate: 99% 7050 aluminum alloy; the 7050 aluminum alloy is composed of the following elements by mass percentage: Mg: 2.6%, Zn: 5.0%, Cu: 2.0%, Mn: 0.07%, and unavoidable impurities Fe≤0.1%, Si≤0.1%, and Al balance. The remaining implementation steps are the same as those of Example 1.

[0141] Performance Testing

[0142] In the above specific embodiments and comparative examples, samples were taken at the center of the actual thickness (wall thickness 40mm, sampled at 20mm), and the tensile mechanical properties of the alloy were tested using "GB / T228-2002: Room Temperature Tensile Test Method for Metallic Materials". Tables 1 and 2 respectively provide statistics on the material composition, mechanical properties and elastic modulus of Examples 1 to 5 and Comparative Examples 1 to 6.

[0143] Table 1: Composition table of materials obtained in Examples 1 to 5 and Comparative Examples 1 to 6 (mass fraction, %)

[0144]

[0145] Table 2: Tensile mechanical properties and elastic modulus of the materials obtained in Examples 1 to 5 and Comparative Examples 1 to 6

[0146]

[0147]

[0148] As shown in Tables 1 and 2, the present invention uses 7050 aluminum alloy as the base material, adds any two or more of graphene, carbon nanotubes, and silicon nitride as modulus improvement phases, and coordinates Al, Zn, Mg, Cu, Mn, and impurities Fe and Si as components to optimize the alloy composition to prepare an aluminum-based composite material with good compatibility of the composite phases and excellent quality. The tensile strength R of the load-bearing member of the aviation transportation vehicle structure prepared by the present invention is m Reach ≥600MPa (20% higher than 7050), specify non-proportional elongation strength R P It reaches ≥500MPa (10% higher than 7050), elastic modulus E reaches 85-101GPa (30% higher than 7050), and elongation after break reaches 8%, showing comprehensive mechanical properties of high strength, high toughness and high modulus.

[0149] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A high modulus aluminum-based composite material for aviation, characterized in that: In terms of weight percentage, it comprises 0.5% to 2.0% of a modulus-improving phase and the remainder of a 7050 aluminum alloy; wherein: The 7050 aluminum alloy includes the following elements in mass percentage: Mg: 1.6% to 3%, Zn: 5.0% to 6.5%, Cu: 1.5% to 2.6%, Mn: 0.05% to 0.1%, and the balance is Al and other inevitable impurities including Fe and Si, and the impurities are ≤ 0.45%; The modulus-improving phase includes two or more of graphene, carbon nanotubes and silicon nitride; the graphene has a particle size of 5-8 μm, and the silicon nitride has a particle size of 3-5 μm; The method for preparing the high modulus aluminum-based composite material for aviation includes preparing the alloy powder of the 7050 aluminum alloy, and preparing the aluminum-based composite material of the alloy powder and the modulus-improving phase; The preparation of the aluminum-based composite material includes the steps of hot isostatic pressing, isothermal forging and solution treatment; the temperature of the heating treatment involved in the preparation of the aluminum-based composite material does not exceed 500°C, thereby preventing the generation of Al4C3.

2. The high modulus aluminum-based composite material for aviation according to claim 1, characterized in that: The modulus-modifying phase consists of graphene, carbon nanotubes and silicon nitride; And / or, the impurities include: Fe: 0.05% to 0.15%, Si: 0.05% to 0.15%; And / or, the number of graphene layers does not exceed 3; And / or, the elastic modulus of the high modulus aluminum-based composite material for aviation is 85 to 101 GPa.

3. An air transport vehicle, characterized in that: It comprises the structural load-bearing component for aviation transportation vehicles, and the structural load-bearing component for aviation transportation vehicles is made of the high modulus aluminum-based composite material for aviation according to claim 1 or 2.

4. The aviation transportation vehicle according to claim 3, characterized in that: The structural load-bearing member for aviation transportation means is a cabin section.

5. A method for preparing a high modulus aluminum-based composite material for aviation as claimed in claim 1 or 2, characterized in that: The invention relates to the preparation of alloy powder of the 7050 aluminum alloy and the preparation of aluminum-based composite material composed of the alloy powder and the modulus improvement; The alloy powder preparation includes the steps of baking, smelting, refining and atomizing powder making; The preparation of the aluminum-based composite material includes the steps of ball milling, hot isostatic pressing, isothermal forging and solution treatment; the temperature of the heating treatment involved in the preparation of the aluminum-based composite material does not exceed 500°C.

6. The preparation method according to claim 5, characterized in that: The following steps are involved: (1) Baking: preheating and keeping the Al, Zn, Mg, Mn and Cu raw materials separately; (2) Melting: During the melting process, at the first temperature, the Al and Cu raw materials obtained in (1) are added and stirred until they are completely melted; when the temperature of the melt is raised to the second temperature, the Zn raw material and the Mn raw material obtained in (1) are added until they are completely melted; when the temperature of the melt is lowered to the third temperature, the Mg raw material obtained in (1) is added and melted, and pressed into the melt and stirred until it is completely melted; (3) Refining: The melt is heated to the refining temperature, and a refining agent is added for refining; the scum is skimmed off and the melt is allowed to stand; a covering agent is added to the melt and stirred in a protective atmosphere; finally, a refiner is added for refining, and the scum is skimmed off to obtain a 7050 aluminum alloy melt; (4) Powdering: The 7050 aluminum alloy melt is heated to a powdering temperature and atomized to obtain the alloy powder; (5) hot isostatic pressing of a blank: adding at least two of the modulus-improving phases to the alloy powder, introducing liquid nitrogen into the powder for ball milling and mixing; hot isostatic pressing the mixed ingredients to obtain an aluminum-based composite blank of a 7050 aluminum alloy reinforced with the modulus-improving phase; (6) Isothermal forging: milling and cleaning the blank obtained in step (5), and then isothermal forging to obtain a forging blank; (7) Solution treatment: The forging blank obtained in step (6) is subjected to heating, heat preservation, water cooling and aging treatment to obtain the aluminum-based composite material.

7. The preparation method according to claim 6, characterized in that: The Al, Zn and Mg raw materials are selected from industrial pure aluminum, industrial pure zinc and industrial pure magnesium respectively; And / or, the Cu raw material is selected from aluminum-copper master alloy; And / or, the Mn raw material is selected from aluminum-manganese master alloy; And / or, the preheating temperature is 200-300°C and the time is 0.5-2h; And / or, the first temperature is 200-300° C.; And / or, the second temperature is 740-800° C.; And / or, the third temperature is 720-740° C.; And / or, the refining temperature is 735-745°C.

8. The preparation method according to claim 6, characterized in that: In step (3) of refining, the refining agent is added for refining for 10 to 20 minutes; And / or, adding a covering agent to the melt and stirring for 5 to 10 minutes in a protective atmosphere of N2 gas; And / or, the covering agent is a mixture comprising MgCl2 and KCl in a mass ratio of 3:2; And / or, the amount of the covering agent added is 0.2% to 1.5% of the total mass of the melt; And / or, the refiner comprises an aluminum-titanium-boron master alloy.

9. The preparation method according to claim 6, characterized in that: In step (4) of powder making, the powder making temperature is 825-835°C; And / or, the atomization pressure is 0.5-1.5 MPa; And / or, the atomizing gas is N2; And / or, the particle size of the alloy powder is 5 to 20 μm.

10. The preparation method according to claim 6, characterized in that: In step (5) of hot isostatic pressing the green sheet, the ball milling time is 3 to 5 hours; And / or, the heating rate of the hot isostatic pressing is 1-3°C / min; And / or, the holding temperature of the hot isostatic pressing is 470-490° C.; And / or, the pressing pressure of the hot isostatic pressing is 35-45 MPa; And / or, the heat preservation and pressure holding time of the hot isostatic pressing is 3 to 5 hours; And / or, in step (7) solution treatment, the heating and heat preservation temperature is 450-500° C. and the time is 8-30 h; And / or, the water temperature of the water cooling is 0-80°C; And / or, the aging treatment is carried out at 100-225° C. for 8-25 hours.

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