Integrated forming method of aluminum-based porous composite material sandwich panel

Abstract

The invention discloses an integrated forming method of an aluminum-based porous composite material sandwich panel, and relates to a preparation method of a sandwich panel. The problems that in a sandwich board structure prepared through an existing gluing method, the bonding interface strength of a panel and a core layer is low, the bonding interface of the panel and core layer metallurgical bonding sandwich board structure prepared from metal powder as the panel is uneven, and the thickness of the core layer is difficult to precisely regulate and control are solved. The aluminum-based porous composite material prepared by a pressure infiltration method is used as the core layer of the sandwich panel structure, and the metal plate or the carbon fiber reinforced aluminum-based porous composite material is used as the panel, so that the energy absorption characteristic of the sandwich panel structure is greatly improved; and the problems that the contact interface of the metal powder and the hollow microspheres is uneven and the thickness of each layer is difficult to accurately regulate and control are solved, the designability is high, and the material selection and the thickness of the metal plate and the core layer can be regulated and controlled according to different application scenes. And the integrated forming operation is simple, the processing and manufacturing cost is reduced, and the engineering application is wider.

Description

Technical Field

[0001] The invention relates to a method for preparing an aluminum-based porous composite material sandwich panel. Background Art

[0002] The modernization of weapons and equipment has put forward higher requirements for the impact protection of military armor, which requires it to have good impact resistance and energy absorption characteristics. Hollow sphere reinforced aluminum-based porous composite materials use hollow spheres and metal matrix to composite, while maintaining low density and having strong mechanical properties; compared with foam aluminum porous materials, the pore structure is controllable and the preparation process is relatively simple, which has great application potential in the field of impact protection.

[0003] The sandwich panel structure is the core component of composite armor, which is generally composed of a face plate and a core layer. In order to achieve high specific strength, specific stiffness and low weight, the face plate is usually made of a high-strength metal sheet, and the core material is usually made of a low-density porous material. The common methods for connecting the face plate and the core material are bonding, welding and powder metallurgy. The sandwich panel structure prepared by the gluing method is prone to stress concentration at the gluing interface and debonding failure, and the bonding strength is poor. The bonding strength of the commonly used epoxy resin adhesive is only about 10MPa; the welding method for preparing the sandwich panel structure is complicated and the processing shape is limited. It is currently used to prepare sandwich panel structures with closed-cell foam aluminum as the core layer; powder metallurgy is a common method for preparing sandwich panel structures with foam metal as the core layer. The method is used to prepare the core layer of hollow sphere reinforced porous material. The ball milling process and the preform preparation process will cause a large number of low-strength hollow spheres to be broken, so this method is not suitable for the preparation of hollow spheres. A sandwich panel structure with a core ball reinforced aluminum-based porous composite material as the core layer; currently, a good method for preparing high volume fraction hollow ball reinforced aluminum-based porous composite materials is pressure infiltration, but the use of pressure infiltration to prepare sandwich panel structures has problems such as uneven metallurgical bonding interface, low interface bonding strength, and difficulty in accurately controlling the core layer thickness. The reason is that during the preparation of the preform, the metal powder with high density in the upper layer enters the hollow ball powder with low density in the core layer under the action of gravity, making the bonding interface between the panel and the core layer uneven. In addition, the falling of metal powder into the core layer will make it difficult to accurately control the thickness of the core layer according to design requirements. Summary of the invention

[0004] In order to solve the problems of low interface strength, uneven interface and difficulty in accurately controlling the thickness of the core layer in the existing sandwich panel structure, the present invention proposes an integrated molding method for an aluminum-based porous composite material sandwich panel.

[0005] The integrated forming method of the aluminum-based porous composite sandwich panel of the present invention is carried out according to the following steps:

[0006] 1. Weighing

[0007] Weigh 30-70% of the hollow balls and the remainder of the aluminum ingot according to volume fraction;

[0008] The aluminum ingot described in step 1 is one of pure Al, Al-Si alloy, Al-Si-Cu alloy, Al-Cu-Mg alloy, Al-Zn-Cu alloy, Al-Zn-Mg-Cu alloy, Al-Si-Cu-Mg alloy, or a combination of several thereof;

[0009] The hollow spheres described in step 1 are one or a combination of hollow alumina spheres, hollow glass microspheres, hollow fly ash spheres, hollow silicon carbide spheres, and expanded perlite;

[0010] 2. Panel material preparation

[0011] The panel material is a metal plate or a carbon fiber cloth; the metal plate or the carbon fiber cloth is cut according to the design requirements, and then the surface is cleaned; the metal plate is hot-dip aluminum-plated;

[0012] The method for hot-dip aluminum plating of the metal plate is as follows: taking an aluminum ingot of the same material as in step 1 and heating it to prepare a molten aluminum liquid, immersing the metal plate in an ammonium chloride plating solution, taking it out and drying it at 250-300° C., immersing the dried metal plate in the molten aluminum liquid, keeping it for 5 minutes, taking it out, and placing it in the air to cool naturally;

[0013] The ammonium chloride auxiliary plating solution is composed of 10% NH4Cl, 20% ZnCl2, 1% NaF and the balance water in terms of mass fraction;

[0014] 3. Preparation of sandwich panel prefabricated body

[0015] The sandwich panel preform is a horizontal sandwich preform or a vertical sandwich preform;

[0016] The preparation method of the horizontal sandwich preform is as follows: a layer of the metal plate or carbon fiber cloth obtained in step 2 is laid flat on the bottom of the steel mold as the lower panel of the sandwich panel structure, a layer of hollow balls is evenly laid on the lower panel and compacted as the core layer of the sandwich panel structure, and another layer of the metal plate or carbon fiber cloth obtained in step 2 is placed on the core layer as the upper panel of the sandwich panel structure to obtain the horizontal sandwich preform;

[0017] The method for preparing the vertical sandwich preform is as follows: vertically placing two metal plates obtained in step 2 in a steel mold, filling hollow balls between the two metal plates and compacting them, thereby obtaining a vertical sandwich preform;

[0018] 4. Preheating and metal matrix preparation:

[0019] The sandwich panel preform obtained in step 3 is placed with the mold in a heating furnace, and a protective gas is introduced and preheated to obtain a preheated preform; then, the aluminum ingot weighed in step 1 is heated to 250 to 450° C. above the melting point under the protective gas to obtain a molten metal matrix;

[0020] 5. Liquid metal infiltration:

[0021] The preheated preform obtained in step 4 is placed with the mold on the table of the press, the molten metal matrix is ​​poured into the mold, and pressure infiltration is performed until the molten metal matrix is ​​completely infiltrated into the preform. After the pressure infiltration is completed, the pressure is maintained, and the preform is demoulded after cooling to room temperature; finally, the obtained aluminum-based porous composite sandwich panel is placed in a heating furnace for heat preservation, and the process is completed;

[0022] The pressure infiltration process described in step 5 is: the pressure is 5-10 MPa, and the infiltration speed is 0.5-1 mm / s;

[0023] After the pressure impregnation in step 5 is completed, the pressure is maintained at 5 to 10 MPa, and the pressure is maintained for 5 to 15 minutes;

[0024] The temperature of the insulation in step 5 is 500-600° C., and the insulation time is 3-10 hours;

[0025] The cooling rate in step five is 10-20°C / min.

[0026] Beneficial effects of the present invention:

[0027] 1. The present invention adopts an aluminum-based porous composite material prepared by a pressure infiltration method as the core layer of the sandwich panel structure. The quasi-static compressive peak stress of the aluminum-based porous composite material reaches 157.3 MPa, which is higher than that of foamed aluminum (the quasi-static compressive peak stress is 10-20 MPa). Therefore, the energy absorption characteristics of the integrated molded sandwich panel structure prepared by the present invention are greatly improved.

[0028] 2. The present invention uses carbon fiber cloth and then composites it with a matrix after subsequent infiltration, and integrates it into a carbon fiber reinforced metal composite material as a panel, which can reduce the weight while ensuring the strength of the panel, and realize the lightweight of the porous composite sandwich panel. The method of using metal plates as panels to prepare preforms instead of laying each layer of powder to prepare the sandwich panel structure avoids the problems of uneven contact interface between metal powder and hollow microspheres caused by the large difference in density between metal powder and hollow microspheres during the filling process and the pressure infiltration process, as well as the difficulty in accurately controlling the thickness of each layer.

[0029] 3. The present invention adopts a pressure infiltration process of preheating the preform under atmosphere protection, and slowly cooling, demolding and then keeping warm to avoid high-temperature oxidation of the metal plate; slow cooling and demolding avoids cracking at the interface between the metal plate and the core layer; high-temperature insulation in a heating furnace after demolding can promote the diffusion of the core layer metal Al in the metal plate metal to form a diffusion layer, and cooperates with hot-dip aluminum plating on the surface of the metal plate to achieve metallurgical bonding of the interface, which has the advantages of resistance to high-temperature oxidation, wear resistance and corrosion resistance.

[0030] 4. The present invention has strong designability, and the material selection and thickness of the metal plate and the core layer can be adjusted according to different application scenarios. The integrated molding operation is simple, and compared with the gluing method and the welding method, the subsequent processing steps are reduced, the processing and manufacturing costs are reduced, and it has a wider range of engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a macroscopic structural photograph of the metallurgically bonded sandwich structure obtained in Example 1. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any reasonable combination of the specific implementation modes.

[0033] Specific implementation method 1: The integrated molding method of the aluminum-based porous composite sandwich panel of this implementation method is carried out according to the following steps:

[0034] 1. Weighing

[0035] Weigh 30-70% of the hollow balls and the remainder of the aluminum ingot according to volume fraction;

[0036] The aluminum ingot described in step 1 is one of pure Al, Al-Si alloy, Al-Si-Cu alloy, Al-Cu-Mg alloy, Al-Zn-Cu alloy, Al-Zn-Mg-Cu alloy, Al-Si-Cu-Mg alloy, or a combination of several thereof;

[0037] The hollow spheres described in step 1 are one or a combination of hollow alumina spheres, hollow glass microspheres, hollow fly ash spheres, hollow silicon carbide spheres, and expanded perlite;

[0038] 2. Panel material preparation

[0039] The panel material is a metal plate or a carbon fiber cloth; the metal plate or the carbon fiber cloth is cut according to the design requirements, and then the surface is cleaned; the metal plate is hot-dip aluminum-plated;

[0040] The method for hot-dip aluminum plating of the metal plate is as follows: taking an aluminum ingot of the same material as in step 1 and heating it to prepare a molten aluminum liquid, immersing the metal plate in an ammonium chloride plating solution, taking it out and drying it at 250-300° C., immersing the dried metal plate in the molten aluminum liquid, keeping it for 5 minutes, taking it out, and placing it in the air to cool naturally;

[0041] The ammonium chloride auxiliary plating solution is composed of 10% NH4Cl, 20% ZnCl2, 1% NaF and the balance water in terms of mass fraction;

[0042] 3. Preparation of sandwich panel prefabricated body

[0043] The sandwich panel preform is a horizontal sandwich preform or a vertical sandwich preform;

[0044] The preparation method of the horizontal sandwich preform is as follows: a layer of the metal plate or carbon fiber cloth obtained in step 2 is laid flat on the bottom of the steel mold as the lower panel of the sandwich panel structure, a layer of hollow balls is evenly laid on the lower panel and compacted as the core layer of the sandwich panel structure, and another layer of the metal plate or carbon fiber cloth obtained in step 2 is placed on the core layer as the upper panel of the sandwich panel structure to obtain the horizontal sandwich preform;

[0045] The method for preparing the vertical sandwich preform is as follows: vertically placing two metal plates obtained in step 2 in a steel mold, filling hollow balls between the two metal plates and compacting them, thereby obtaining a vertical sandwich preform;

[0046] 4. Preheating and metal matrix preparation:

[0047] The sandwich panel preform obtained in step 3 is placed with the mold in a heating furnace, and a protective gas is introduced and preheated to obtain a preheated preform; then, the aluminum ingot weighed in step 1 is heated to 250 to 450° C. above the melting point under the protective gas to obtain a molten metal matrix;

[0048] 5. Liquid metal infiltration:

[0049] The preheated preform obtained in step 4 is placed with the mold on the table of the press, the molten metal matrix is ​​poured into the mold, and pressure infiltration is performed until the molten metal matrix is ​​completely infiltrated into the preform. After the pressure infiltration is completed, the pressure is maintained, and the preform is demoulded after cooling to room temperature; finally, the obtained aluminum-based porous composite sandwich panel is placed in a heating furnace for heat preservation, and the process is completed;

[0050] The pressure infiltration process described in step 5 is: the pressure is 5-10 MPa, and the infiltration speed is 0.5-1 mm / s;

[0051] After the pressure impregnation in step 5 is completed, the pressure is maintained at 5 to 10 MPa, and the pressure is maintained for 5 to 15 minutes;

[0052] The temperature of the insulation in step 5 is 500-600° C., and the insulation time is 3-10 hours;

[0053] The cooling rate in step five is 10-20°C / min.

[0054] This embodiment has the following beneficial effects:

[0055] 1. This embodiment adopts an aluminum-based porous composite material prepared by a pressure infiltration method as the core layer of the sandwich panel structure. The quasi-static compressive peak stress of the aluminum-based porous composite material reaches 157.3 MPa, which is much higher than that of foamed aluminum (the quasi-static compressive peak stress is 10-20 MPa). Therefore, the energy absorption characteristics of the integrated molded sandwich panel structure prepared in this embodiment are greatly improved.

[0056] 2. This embodiment uses carbon fiber cloth and then composites it with a matrix after subsequent infiltration, and integrates it into a carbon fiber reinforced metal composite material as a panel, which can reduce the weight while ensuring the strength of the panel, and realize the lightweight of the porous composite sandwich panel. The method of using metal plates as panels to prepare preforms instead of laying each layer of powder to prepare the sandwich panel structure avoids the problem of uneven contact interface between metal powder and hollow microspheres during the filling process and pressure infiltration process caused by the large difference in density between metal powder and hollow microspheres, and the difficulty in accurately controlling the thickness of each layer.

[0057] 3. This embodiment adopts a pressure infiltration process of preheating the preform under atmosphere protection, and slowly cooling, demolding and then keeping warm to avoid high-temperature oxidation of the metal plate; slow cooling and demolding avoids cracking at the interface between the metal plate and the core layer; high-temperature insulation in the heating furnace after demolding can promote the diffusion of the core layer metal Al in the metal plate metal to form a diffusion layer, and cooperate with hot-dip aluminum plating on the surface of the metal plate to achieve metallurgical bonding of the interface, which has the advantages of resistance to high-temperature oxidation, wear resistance and corrosion resistance.

[0058] 4. This embodiment has strong designability, and the material selection and thickness of the metal plate and the core layer can be adjusted according to different application scenarios. The integrated molding operation is simple, and compared with the gluing method and the welding method, the subsequent processing steps are reduced, the processing and manufacturing costs are reduced, and it has a wider range of engineering applications.

[0059] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that the average particle size of the hollow spheres described in step 1 is 15 to 200 μm.

[0060] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that: the metal plate described in step two is made of steel, aluminum alloy, titanium alloy or magnesium alloy.

[0061] Specific implementation method 4: This implementation method is different from any one of specific implementation methods 1 to 3 in that: the thickness of the metal plate described in step 2 is 1 to 50 mm.

[0062] Specific implementation method five: This implementation method is different from any one of specific implementation methods one to four in that: the carbon fiber cloth described in step two is M40J carbon fiber cloth.

[0063] Specific embodiment 6: This embodiment differs from any one of the specific embodiments 1 to 5 in that: the metal plate surface in the horizontal sandwich preform described in step 3 is perforated with a hole diameter of 2 mm and a perforation density of 2 holes / cm 2 Punching is conducive to the smooth progress of pressure infiltration. A porous structure is designed on the surface of the metal plate. During pressure infiltration, the molten aluminum alloy flows into the pore structure of the metal panel, forming a double interpenetrating interface with the metal panel that matches mechanical bite and metallurgical bonding, thereby increasing the interface bonding strength.

[0064] Specific implementation method 7: This implementation method is different from any one of specific implementation methods 1 to 6 in that: the ply thickness of the carbon fiber cloth in the horizontal sandwich preform described in step 3 is 1 to 50 mm.

[0065] Specific implementation eight: This implementation differs from any one of specific implementations one to seven in that the thickness of the hollow sphere layer in the horizontal sandwich preform described in step three is 10 to 100 mm.

[0066] Specific implementation method 9: This implementation method is different from any one of specific implementation methods 1 to 8 in that: in the vertical sandwich preform described in step 3, two metal plates are arranged in parallel with a spacing of 10 to 100 mm.

[0067] Specific implementation method ten: This implementation method is different from any one of specific implementation methods one to nine in that: the protective gas in step four is nitrogen, helium or argon, and the gas pressure is 0.1 MPa to 10 MPa.

[0068] Embodiment 1:

[0069] The integrated molding method of the aluminum-based porous composite sandwich panel of this embodiment is carried out according to the following steps:

[0070] 1. Weighing

[0071] Weigh 60% of hollow glass microspheres and the remainder of aluminum ingots by volume;

[0072] The aluminum ingot described in step 1 is Al-12Si alloy; the mass fraction of Si in the Al-12Si alloy is 12%;

[0073] The average particle size of the hollow spheres described in step 1 is 20 μm;

[0074] 2. Panel material preparation

[0075] Cut the metal plate according to the design requirements, and then remove impurities from the surface; hot-dip aluminum coating the metal plate;

[0076] The method for hot-dip aluminum plating of the metal plate is as follows: taking an aluminum ingot of the same material as in step 1 and heating it to prepare a molten aluminum liquid, immersing the metal plate in an ammonium chloride plating solution, taking it out and drying it at 250° C., immersing the dried metal plate in the molten aluminum liquid, keeping it for 5 minutes, taking it out, and placing it in the air to cool naturally;

[0077] The ammonium chloride auxiliary plating solution is composed of 10% NH4Cl, 20% ZnCl2, 1% NaF and the balance water in terms of mass fraction;

[0078] The metal plate in step 2 is made of Q235 steel;

[0079] The thickness of the metal plate in step 2 is 2 mm;

[0080] 3. Preparation of sandwich panel prefabricated body

[0081] The sandwich panel preform is a vertical sandwich preform;

[0082] The method for preparing the vertical sandwich preform is as follows: vertically placing two metal plates obtained in step 2 in a steel mold, filling hollow balls between the two metal plates and compacting them, thereby obtaining a vertical sandwich preform;

[0083] In the vertical sandwich preform described in step 3, two metal plates are arranged in parallel with a spacing of 10 mm;

[0084] 4. Preheating and metal matrix preparation:

[0085] The sandwich panel preform obtained in step 3 is placed with the mold in a heating furnace, and a protective gas is introduced and preheated to obtain a preheated preform; then, the aluminum ingot weighed in step 1 is heated to 450° C. above the melting point under the protective gas to obtain a molten metal matrix;

[0086] The protective gas in step 4 is argon gas, and the gas pressure is 0.1 MPa;

[0087] 5. Liquid metal infiltration:

[0088] The preheated preform obtained in step 4 is placed on the table of the press with the mold, the molten metal matrix is ​​poured into the mold, and pressure infiltration is performed until the molten metal matrix is ​​completely infiltrated into the preform. After the pressure infiltration is completed, the pressure is maintained, and the preform is demoulded after cooling to room temperature; finally, the obtained aluminum-based porous composite sandwich panel is placed in a heating furnace for insulation, and the process is completed.

[0089] The pressure infiltration process described in step 5 is: the pressure is 10MPa, and the infiltration speed is 1mm / s;

[0090] After the pressure impregnation in step 5 is completed, the pressure is maintained at 10 MPa, and the pressure maintenance time is 10 min;

[0091] The temperature of the insulation in step 5 is 550° C. and the insulation time is 3 hours;

[0092] The cooling rate in step five is 10°C / min.

[0093] Figure 1 This is a macroscopic structural photograph of the metallurgically bonded sandwich structure obtained in Example 1. It can be seen that the interface between the face plate and the core layer in the prepared sandwich panel structure is flat, and the formed metallurgical bonding layer makes the interface between the face plate and the core layer have a high bonding strength. The bonding strength between the face plate and the core layer of the aluminum-based porous composite sandwich panel prepared in Example 1 is 41.3MPa, which is 5.4 times the bonding strength (7.6MPa) of the comparative adhesive.

[0094] Example 2

[0095] The integrated molding method of the aluminum-based porous composite sandwich panel of this embodiment is carried out according to the following steps:

[0096] 1. Weighing

[0097] Weigh 70% of the hollow glass microspheres and the remainder of the aluminum ingot according to volume fraction;

[0098] The aluminum ingot described in step 1 is A356 aluminum alloy; the mass fraction of Si in the A356 aluminum alloy is 7%;

[0099] The average particle size of the hollow spheres described in step 1 is 20 μm;

[0100] 2. Panel material preparation

[0101] Take the carbon fiber cloth and cut it according to the design requirements, and then remove impurities from the surface;

[0102] The carbon fiber cloth described in step 2 is M40J carbon fiber cloth;

[0103] 3. Preparation of sandwich panel prefabricated body

[0104] The sandwich panel preform is a horizontal sandwich preform; the preparation method of the horizontal sandwich preform is: a layer of carbon fiber cloth obtained in step 2 is laid flat on the bottom of the steel mold as the lower panel of the sandwich panel structure, a layer of hollow balls is evenly laid on the lower panel and compacted as the core layer of the sandwich panel structure, and another layer of carbon fiber cloth obtained in step 2 is placed on the core layer as the upper panel of the sandwich panel structure to obtain the horizontal sandwich preform;

[0105] The layer thickness of the carbon fiber cloth in the horizontal sandwich preform described in step 3 is 2 mm;

[0106] The thickness of the hollow sphere layer in the horizontal sandwich preform described in step 3 is 10 mm;

[0107] 4. Preheating and metal matrix preparation:

[0108] The sandwich panel preform obtained in step 3 is placed with the mold in a heating furnace, and a protective gas is introduced and preheated to obtain a preheated preform; then, the aluminum ingot weighed in step 1 is heated to 300° C. above the melting point under the protective gas to obtain a molten metal matrix;

[0109] The protective gas in step 4 is nitrogen, and the gas pressure is 5 MPa;

[0110] 5. Liquid metal infiltration:

[0111] The preheated preform obtained in step 4 is placed on the table of the press with the mold, the molten metal matrix is ​​poured into the mold, and pressure infiltration is performed until the molten metal matrix is ​​completely infiltrated into the preform. After the pressure infiltration is completed, the pressure is maintained, and the preform is demoulded after cooling to room temperature; finally, the obtained aluminum-based porous composite sandwich panel is placed in a heating furnace for insulation, and the process is completed.

[0112] The pressure infiltration process described in step 5 is: the pressure is 10MPa, and the infiltration speed is 0.5mm / s;

[0113] After the pressure impregnation in step 5 is completed, the pressure is maintained at 10 MPa for 15 minutes;

[0114] The temperature of the insulation in step 5 is 500° C. and the insulation time is 5 hours;

[0115] The cooling rate in step five is 15°C / min.

[0116] The bonding strength between the face plate and the core layer of the aluminum-based porous composite sandwich panel prepared in Example 2 is 67.1 MPa, which is 8.8 times the bonding strength of the comparative adhesive (7.6 MPa).

[0117] Example 3

[0118] The integrated molding method of the aluminum-based porous composite sandwich panel of this embodiment is carried out according to the following steps:

[0119] 1. Weighing

[0120] Weigh 65% of hollow glass microspheres and the remainder of aluminum ingots by volume;

[0121] The aluminum ingot described in step 1 is Al-12Si alloy; the mass fraction of Si in the Al-12Si alloy is 12%

[0122] The average particle size of the hollow spheres described in step 1 is 20 μm;

[0123] 2. Panel material preparation

[0124] Take the metal sheet cloth and cut it according to the design requirements, then remove impurities from the surface; hot-dip aluminum coating the metal sheet;

[0125] The method for hot-dip aluminum plating of the metal plate is as follows: take an aluminum ingot of the same material as in step 1 and heat it to prepare a molten aluminum liquid, immerse the metal plate in an ammonium chloride plating solution, take it out and dry it at 300° C., immerse the dried metal plate in the molten aluminum liquid, keep it for 5 minutes, take it out, and place it in the air to cool naturally;

[0126] The ammonium chloride auxiliary plating solution is composed of 10% NH4Cl, 20% ZnCl2, 1% NaF and the balance water in terms of mass fraction;

[0127] The metal plate described in step 2 is made of Q235 steel;

[0128] The thickness of the metal plate in step 2 is 2 mm;

[0129] 3. Preparation of sandwich panel prefabricated body

[0130] The sandwich panel preform is a horizontal sandwich preform;

[0131] The preparation method of the horizontal sandwich preform is as follows: a layer of the metal plate obtained in step 2 is laid flat on the bottom of the steel mold as the lower panel of the sandwich panel structure, a layer of hollow balls is evenly laid on the lower panel and compacted as the core layer of the sandwich panel structure, and another layer of the metal plate obtained in step 2 is placed on the core layer as the upper panel of the sandwich panel structure to obtain the horizontal sandwich preform;

[0132] The metal plate surface in the horizontal sandwich preform described in step 3 is punched with holes of 2 mm in diameter and a punching density of 2 holes / cm 2 ; Punching is conducive to the smooth progress of pressure impregnation;

[0133] The thickness of the hollow sphere layer in the horizontal sandwich preform described in step 3 is 20 mm;

[0134] 4. Preheating and metal matrix preparation:

[0135] The sandwich panel preform obtained in step 3 is placed with the mold in a heating furnace, and a protective gas is introduced and preheated to obtain a preheated preform; then, the aluminum ingot weighed in step 1 is heated to 350° C. above the melting point under the protective gas to obtain a molten metal matrix;

[0136] The protective gas in step 4 is helium, and the gas pressure is 5 MPa;

[0137] 5. Liquid metal infiltration:

[0138] The preheated preform obtained in step 4 is placed on the table of the press with the mold, the molten metal matrix is ​​poured into the mold, and pressure infiltration is performed until the molten metal matrix is ​​completely infiltrated into the preform. After the pressure infiltration is completed, the pressure is maintained, and the preform is demoulded after cooling to room temperature; finally, the obtained aluminum-based porous composite sandwich panel is placed in a heating furnace for insulation, and the process is completed.

[0139] The pressure infiltration process described in step 5 is: the pressure is 5 MPa, and the infiltration speed is 1 mm / s;

[0140] After the pressure impregnation in step 5 is completed, the pressure is maintained at 10 MPa, and the pressure maintenance time is 5 minutes;

[0141] The temperature of the insulation in step 5 is 550° C. and the insulation time is 5 hours;

[0142] The cooling rate in step five is 10°C / min.

[0143] The bonding strength between the face plate and the core layer of the aluminum-based porous composite sandwich panel prepared in Example 3 is 44.7 MPa, which is 5.9 times the bonding strength of the comparative adhesive (7.6 MPa).

[0144] Comparative Example:

[0145] The preparation of the aluminum-based porous composite sandwich panel by the adhesive bonding method in this comparative example is carried out according to the following steps:

[0146] 1. Material preparation

[0147] Weigh 60% of hollow glass microspheres and the remainder of aluminum ingots by volume; weigh epoxy resin and epoxy curing agent; cut the metal plate according to the design requirements, and then remove impurities from the surface;

[0148] The aluminum ingot described in step 1 is Al-12Si alloy; the mass fraction of Si in the Al-12Si alloy is 12%

[0149] The average particle size of the hollow spheres described in step 1 is 20 μm;

[0150] The epoxy resin in step 1 is E-44, and the epoxy curing agent is 650, and the mass ratio is 1:1;

[0151] The metal plate in step 1 is made of Q235 steel;

[0152] The thickness of the metal plate in step 1 is 2 mm;

[0153] 2. Preparation of preform of core aluminum-based porous composite material

[0154] The hollow glass microspheres prepared in step 1 are placed in a mold, compacted and then moved to a heating furnace for preheating to obtain a preheated preform; the aluminum ingot weighed in step 1 is heated to 450° C. above the melting point under a protective atmosphere to obtain a molten metal matrix;

[0155] The protective atmosphere is argon gas, and the gas pressure is 0.1MPa;

[0156] 3. Liquid metal infiltration:

[0157] The preheated preform obtained in step 2 is placed on the table of the press with the mold, and the molten metal matrix is ​​poured onto the preform in the mold for pressure infiltration. After the pressure infiltration is completed, the preform is cooled to room temperature and finally demolded;

[0158] The process of pressure infiltration is as follows: the pressure is 10 MPa and the infiltration speed is 1 mm / s.

[0159] 4. Preparation of composite sandwich panels:

[0160] The epoxy resin (E-44) and epoxy curing agent (650) weighed in step 1 are mixed and stirred evenly, and the epoxy resin adhesive is evenly applied between the metal panel and the core layer, and pressed to make them firmly bonded; then, they are placed in a drying oven at 80°C and kept warm for 2 hours, and then taken out to obtain a composite sandwich panel.

[0161] The bonding strength between the face plate and the core layer of the aluminum-based porous composite sandwich panel prepared by the comparative adhesive method is 7.6 MPa.

Claims

1. An integrated molding method for an aluminum-based porous composite sandwich panel, characterized in that: The integrated molding method of the aluminum-based porous composite sandwich panel is carried out according to the following steps:

1. Weighing Weigh 30-70% of the hollow balls and the remainder of the aluminum ingot according to volume fraction; The aluminum ingot described in step 1 is one of pure Al, Al-Si alloy, Al-Si-Cu alloy, Al-Cu-Mg alloy, Al-Zn-Cu alloy, Al-Zn-Mg-Cu alloy, Al-Si-Cu-Mg alloy, or a combination of several thereof; The hollow spheres described in step 1 are one or a combination of alumina hollow spheres, glass microsphere hollow spheres, fly ash hollow spheres, silicon carbide hollow spheres, and expanded perlite; 2. Panel material preparation The panel material is a metal plate or a carbon fiber cloth; the metal plate or the carbon fiber cloth is cut according to the design requirements, and then the surface is cleaned; the metal plate is hot-dip aluminum-plated; The method for hot-dip aluminum plating of the metal plate is as follows: taking an aluminum ingot of the same material as in step 1 and heating it to prepare a molten aluminum liquid, immersing the metal plate in an ammonium chloride plating solution, taking it out and drying it at 250-300° C., immersing the dried metal plate in the molten aluminum liquid, keeping it for 5 minutes, taking it out, and placing it in the air to cool naturally; The ammonium chloride auxiliary plating solution is composed of 10% NH4Cl, 20% ZnCl2, 1% NaF and the balance water by mass fraction; 3. Preparation of sandwich panel prefabricated body The sandwich panel preform is a horizontal sandwich preform or a vertical sandwich preform; The preparation method of the horizontal sandwich preform is as follows: a layer of the metal plate or carbon fiber cloth obtained in step 2 is laid flat on the bottom of the steel mold as the lower panel of the sandwich panel structure, a layer of hollow balls is evenly laid on the lower panel and compacted as the core layer of the sandwich panel structure, and another layer of the metal plate or carbon fiber cloth obtained in step 2 is placed on the core layer as the upper panel of the sandwich panel structure to obtain the horizontal sandwich preform; The method for preparing the vertical sandwich preform is as follows: vertically placing two metal plates obtained in step 2 in a steel mold, filling hollow balls between the two metal plates and compacting them, thereby obtaining a vertical sandwich preform; 4. Preheating and metal matrix preparation: The sandwich panel preform obtained in step 3 is placed with the mold in a heating furnace, and a protective gas is introduced and preheated to obtain a preheated preform; then, the aluminum ingot weighed in step 1 is heated to 250 to 450° C. above the melting point under the protective gas to obtain a molten metal matrix; 5. Liquid metal infiltration: The preheated preform obtained in step 4 is placed with the mold on the table of the press, the molten metal matrix is ​​poured into the mold, and pressure infiltration is performed until the molten metal matrix is ​​completely infiltrated into the preform. After the pressure infiltration is completed, the pressure is maintained, and the preform is demoulded after cooling to room temperature; finally, the obtained aluminum-based porous composite sandwich panel is placed in a heating furnace for heat preservation, and the process is completed; The pressure infiltration process described in step 5 is: the pressure is 5-10 MPa, and the infiltration speed is 0.5-1 mm / s; After the pressure impregnation in step 5 is completed, the pressure is maintained at 5 to 10 MPa, and the pressure maintenance time is 5 to 15 minutes; The temperature of the insulation in step 5 is 500-600° C., and the insulation time is 3-10 hours; The cooling rate in step five is 10-20°C / min.

2. The integrated molding method of the aluminum-based porous composite sandwich panel according to claim 1, characterized in that: The average particle size of the hollow spheres described in step 1 is 15 to 200 μm.

3. The integrated molding method of the aluminum-based porous composite sandwich panel according to claim 1, characterized in that: The metal plate described in step 2 is made of steel, aluminum alloy, titanium alloy or magnesium alloy.

4. The integrated molding method of aluminum-based porous composite sandwich panel according to claim 1, characterized in that: The thickness of the metal plate in step 2 is 1 to 50 mm.

5. The integrated molding method of aluminum-based porous composite sandwich panel according to claim 1, characterized in that: The carbon fiber cloth described in step 2 is M40J carbon fiber cloth.

6. The integrated molding method of aluminum-based porous composite sandwich panel according to claim 1, characterized in that: The metal plate surface in the horizontal sandwich preform described in step 3 is punched with holes of 2 mm in diameter and a punching density of 2 holes / cm 2 ; Punching is conducive to the smooth progress of pressure infiltration.

7. The integrated molding method of aluminum-based porous composite sandwich panel according to claim 1, characterized in that: The ply thickness of the carbon fiber cloth in the horizontal sandwich preform described in step 3 is 1 to 50 mm.

8. The integrated molding method of aluminum-based porous composite sandwich panel according to claim 1, characterized in that: The thickness of the hollow sphere layer in the horizontal sandwich preform described in step 3 is 10 to 100 mm.

9. The integrated molding method of aluminum-based porous composite sandwich panel according to claim 1, characterized in that: In the vertical sandwich preform described in step 3, two metal plates are arranged in parallel with a spacing of 10 to 100 mm.

10. The integrated molding method of aluminum-based porous composite sandwich panel according to claim 1, characterized in that: The protective gas described in step 4 is nitrogen, helium or argon, and the gas pressure is 0.1MPa to 10MPa.

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