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

Abstract

The invention belongs to the technical field of composite material preparation, and discloses an integrated forming method of an aluminum-based porous composite material 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 present invention relates to the technical field of composite material preparation, and in particular to an integrated molding method of an aluminum-based porous composite material sandwich panel. Background Art

[0002] The modernization of weaponry places higher demands on the impact protection of military armor, requiring it to possess excellent impact resistance and energy absorption properties. Hollow sphere-reinforced aluminum-based porous composites, combining hollow spheres with a metal matrix, achieve strong mechanical properties while maintaining a low density. Compared to porous aluminum foams, they offer controllable pore structure and a simpler preparation process, showing great potential for application in impact protection.

[0003] The sandwich panel structure is the core component of composite armor, and 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 has poor bonding strength. The bonding strength of commonly used epoxy resin adhesives is only about 10MPa; the welding method for preparing sandwich panel structures is complex and the processing shape is limited. It is currently mostly 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 a core layer of hollow sphere reinforced porous material. The ball milling process and preform preparation process will cause a large amount of low-strength hollow spheres to be broken, so this method is not suitable. The preparation of sandwich panel structures with hollow sphere reinforced aluminum-based porous composite materials as the core layer is a good method for preparing high-volume-fraction hollow sphere reinforced aluminum-based porous composite materials. However, the pressure infiltration method for preparing sandwich panel structures has problems such as uneven metallurgical bonding interface and difficulty in accurately controlling the thickness of the core layer. The reason is that during the preparation of the preform, the metal powder with high density in the upper layer enters the hollow sphere powder with low density in the core layer due to gravity, making the bonding interface between the panel and the core layer uneven. In addition, the metal powder falling into the core layer makes it difficult to accurately control the thickness of the core layer according to design requirements. This has also become a key problem in the use of pressure infiltration to achieve integrated molding to prepare aluminum-based porous composite sandwich panel structures. Summary of the Invention

[0004] In order to solve the problems of low adhesive interface strength between the face plate and the core layer in the sandwich panel structure prepared by the existing gluing method, uneven bonding interface of the sandwich panel structure metallurgically bonded with the face plate and the core layer prepared by using metal powder as the face plate, and difficulty in accurately controlling the thickness of the core layer, the present invention proposes an integrated molding method for aluminum-based porous composite sandwich panels.

[0005] The integrated molding 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 40-70% of the hollow balls and the remainder of the aluminum ingot according to the 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 balls in step 1 are one or a combination of alumina hollow balls, glass microsphere hollow balls, fly ash hollow balls, silicon carbide hollow balls, and expanded perlite;

[0010] 2. Panel material preparation

[0011] Take the metal plate or carbon fiber cloth and cut it according to the design requirements, and then remove the impurities on the surface;

[0012] 3. Preparation of sandwich panel prefabricated body

[0013] The sandwich panel prefabricated body is a horizontal sandwich prefabricated body or a vertical sandwich prefabricated body;

[0014] The horizontal sandwich preform is prepared by laying a layer of metal plate or carbon fiber cloth on the bottom of a steel mold as a lower panel of a sandwich panel structure, evenly laying a layer of hollow balls on the lower panel and vibrating them to form a core layer of the sandwich panel structure, and placing another layer of metal plate or carbon fiber cloth on the core layer as an upper panel of the sandwich panel structure to obtain the horizontal sandwich preform;

[0015] The vertical sandwich preform is prepared by vertically placing two metal plates in a steel mold, filling the space between the two metal plates with hollow balls and compacting the space between the two metal plates with vibration to obtain the vertical sandwich preform;

[0016] 4. Preheating and metal matrix preparation:

[0017] 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;

[0018] 5. Liquid metal infiltration:

[0019] The preheated preform obtained in step 4 is placed on the press table 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 heat preservation, and the process is completed.

[0020] The pressure infiltration process in step 5 is as follows: the pressure is 5-10 MPa and the infiltration speed is 0.5-1 mm / s;

[0021] After the pressure impregnation in step 5 is completed, the holding pressure is 5 to 10 MPa and the holding time is 5 to 15 minutes;

[0022] The holding temperature in step 5 is 500-600° C. and the holding time is 10-20 hours;

[0023] The cooling rate in step 5 is 10-20°C / min.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 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, and a metal plate or carbon fiber reinforced aluminum-based porous composite material as the face plate; the quasi-static compressive peak stress of the aluminum-based porous composite material reaches 157.3 MPa, which is significantly improved compared with 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 significantly improved.

[0026] 2. The present invention adopts a metal plate as a panel to prepare a preform instead of using the powder metallurgy method to lay out layers of powder to prepare a sandwich panel structure, thereby avoiding the problems 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, as well as the difficulty in accurately controlling the thickness of each layer.

[0027] 3. The present invention adopts a pressure infiltration process of preheating the preform under atmosphere protection, slow cooling and demoulding, and then heat preservation to avoid high-temperature oxidation of the metal plate; slow cooling and demoulding avoids cracking of the interface between the metal plate and the core layer; high-temperature insulation in a heating furnace after demoulding can promote the diffusion of the core layer metal Al in the metal of the metal plate to form a diffusion layer, thereby achieving strong interface bonding.

[0028] 4. The present invention is highly designable, and the material selection and thickness of the metal plate and core layer can be adjusted according to different application scenarios. The integrated molding operation is simple, reducing processing and manufacturing costs, and has a wider range of engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1This is a macroscopic photograph of the metallurgically bonded sandwich structure obtained in Example 1. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is not limited to the specific implementation methods listed below, but also includes any reasonable combination of the specific implementation methods.

[0031] Specific embodiment 1: The integrated molding method of the aluminum-based porous composite sandwich panel of this embodiment is carried out according to the following steps:

[0032] 1. Weighing

[0033] Weigh 40-70% of the hollow balls and the remainder of the aluminum ingot according to volume fraction;

[0034] 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;

[0035] The hollow balls in step 1 are one or a combination of alumina hollow balls, glass microsphere hollow balls, fly ash hollow balls, silicon carbide hollow balls, and expanded perlite;

[0036] 2. Panel material preparation

[0037] Take the metal plate or carbon fiber cloth and cut it according to the design requirements, and then remove the impurities on the surface;

[0038] 3. Preparation of sandwich panel prefabricated body

[0039] The sandwich panel prefabricated body is a horizontal sandwich prefabricated body or a vertical sandwich prefabricated body;

[0040] The horizontal sandwich preform is prepared by laying a layer of metal plate or carbon fiber cloth on the bottom of a steel mold as a lower panel of a sandwich panel structure, evenly laying a layer of hollow balls on the lower panel and vibrating them to form a core layer of the sandwich panel structure, and placing another layer of metal plate or carbon fiber cloth on the core layer as an upper panel of the sandwich panel structure to obtain the horizontal sandwich preform;

[0041] The vertical sandwich preform is prepared by vertically placing two metal plates in a steel mold, filling the space between the two metal plates with hollow balls and compacting the space between the two metal plates with vibration to obtain the vertical sandwich preform;

[0042] 4. Preheating and metal matrix preparation:

[0043] The sandwich panel preform obtained in step 4 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;

[0044] 5. Liquid metal infiltration:

[0045] The preheated preform obtained in step 4 is placed on the press table 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 heat preservation, and the process is completed.

[0046] The pressure infiltration process in step 5 is as follows: the pressure is 5-10 MPa and the infiltration speed is 0.5-1 mm / s;

[0047] After the pressure impregnation in step 5 is completed, the holding pressure is 5 to 10 MPa and the holding time is 5 to 15 minutes;

[0048] The holding temperature in step 5 is 500-600° C. and the holding time is 10-20 hours;

[0049] The cooling rate in step 5 is 10-20°C / min.

[0050] This embodiment has the following beneficial effects:

[0051] 1. This embodiment uses an aluminum-based porous composite material prepared by a pressure infiltration method as the core layer of the sandwich panel structure, and a metal plate or carbon fiber reinforced aluminum-based porous composite material as the face plate; the quasi-static compressive peak stress of the aluminum-based porous composite material reaches 157.3 MPa, which is significantly improved compared to 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 significantly improved.

[0052] 2. This embodiment uses metal plates as panels to prepare preforms instead of using the powder metallurgy method to lay out layers of powder to prepare sandwich panel structures. This avoids the problems of uneven contact interfaces between metal powder and hollow microspheres during the filling process and pressure infiltration process caused by the large density difference between metal powder and hollow spheres, as well as the difficulty in accurately controlling the thickness of each layer.

[0053] 3. This embodiment adopts a pressure infiltration process of preheating the preform under atmosphere protection, slow cooling and demoulding, and then heat preservation to avoid high-temperature oxidation of the metal plate; slow cooling and demoulding avoids cracking of the interface between the metal plate and the core layer; high-temperature insulation in a heating furnace after demoulding can promote the diffusion of the core layer metal Al in the metal of the metal plate to form a diffusion layer, thereby achieving strong bonding at the interface.

[0054] 4. This embodiment is highly designable, allowing the material selection and thickness of the metal plate and core layer to be adjusted according to different application scenarios. The integrated molding process is simple to operate, reduces processing and manufacturing costs, and has a wider range of engineering applications.

[0055] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the average particle size of the hollow spheres described in step 1 is 15 to 200 μm.

[0056] Specific embodiment three: This embodiment differs from specific embodiment one or two in that the metal plate in step two is made of steel, aluminum alloy, titanium alloy or magnesium alloy.

[0057] Specific embodiment 4: This embodiment differs from any one of specific embodiments 1 to 3 in that the thickness of the metal plate in step 2 is 1 to 50 mm.

[0058] Specific embodiment 5: This embodiment differs from any one of specific embodiments 1 to 4 in that the carbon fiber cloth described in step 2 is M40J carbon fiber cloth.

[0059] Specific embodiment 6: The difference between this embodiment and any one of the specific embodiments 1 to 5 is 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.

[0060] Specific embodiment seven: This embodiment differs from any one of specific embodiments one to six in that the ply thickness of the carbon fiber cloth in the horizontal sandwich preform described in step three is 1 to 50 mm.

[0061] Specific embodiment eight: This embodiment differs from any one of specific embodiments 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.

[0062] Specific embodiment 9: This embodiment differs from any one of specific embodiments 1 to 8 in that: in the vertical sandwich preform described in step 3, the two metal plates are arranged in parallel with a spacing of 10 to 100 mm.

[0063] Specific embodiment ten: This embodiment differs from any one of specific embodiments 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.

[0064] Example 1

[0065] The integrated molding method of the aluminum-based porous composite sandwich panel of this embodiment is carried out according to the following steps:

[0066] 1. Weighing

[0067] Weigh 60% of the hollow glass microspheres and the remainder of the aluminum ingot according to volume fraction;

[0068] The aluminum ingot in step 1 is an Al-12Si alloy; the mass fraction of Si in the Al-12Si alloy is 12%;

[0069] The average particle size of the hollow spheres in step 1 is 20 μm;

[0070] 2. Panel material preparation

[0071] Take the metal plate and cut it according to the design requirements, then remove the impurities on the surface;

[0072] The metal plate in step 2 is made of Q235 steel;

[0073] The thickness of the metal plate in step 2 is 2 mm;

[0074] 3. Preparation of sandwich panel prefabricated body

[0075] The sandwich panel prefabricated body is a vertical sandwich prefabricated body;

[0076] The vertical sandwich preform is prepared by vertically placing two metal plates in a steel mold, filling the space between the two metal plates with hollow balls and compacting the space between the two metal plates with vibration to obtain the vertical sandwich preform;

[0077] In the vertical sandwich preform described in step 3, the two metal plates are arranged in parallel with a spacing of 10 mm;

[0078] 4. Preheating and metal matrix preparation:

[0079] The sandwich panel preform obtained in step 4 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;

[0080] The protective gas in step 4 is argon gas, and the gas pressure is 0.1 MPa;

[0081] 5. Liquid metal infiltration:

[0082] The preheated preform obtained in step 4 is placed on the press table 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.

[0083] The pressure infiltration process in step 5 is as follows: the pressure is 10 MPa and the infiltration speed is 1 mm / s;

[0084] After the pressure impregnation in step 5 is completed, the holding pressure is 10 MPa and the holding time is 10 minutes;

[0085] The holding temperature in step 5 is 550° C. and the holding time is 12 h.

[0086] The cooling rate in step 5 is 10°C / min.

[0087] Figure 1 This is a macroscopic photograph of the metallurgically bonded sandwich structure obtained in Example 1. It can be seen that the interface between the faceplate and core layer of the prepared sandwich panel is smooth, and the metallurgical bonding layer formed provides a high bond strength between the faceplate and core layer. The bond strength between the faceplate and core layer of the aluminum-based porous composite sandwich panel prepared in Example 1 is 27.5 MPa, 3.6 times the adhesive bond strength (7.6 MPa) of the comparative example.

[0088] Example 2

[0089] The integrated molding method of the aluminum-based porous composite sandwich panel of this embodiment is carried out according to the following steps:

[0090] 1. Weighing

[0091] Weigh 70% of the hollow glass microspheres and the remainder of the aluminum ingot according to volume fraction;

[0092] The aluminum ingot in step 1 is A356 aluminum alloy; the mass fraction of Si in A356 aluminum alloy is 7%;

[0093] The average particle size of the hollow spheres in step 1 is 20 μm;

[0094] 2. Panel material preparation

[0095] Take the carbon fiber cloth and cut it according to the design requirements, then remove impurities from the surface;

[0096] The carbon fiber cloth described in step 2 is M40J carbon fiber cloth;

[0097] 3. Preparation of sandwich panel prefabricated body

[0098] The sandwich panel preform is a horizontal sandwich preform. The preparation method of the horizontal sandwich preform is as follows: a layer of carbon fiber cloth is laid flatly on the bottom of a steel mold as a lower panel of the sandwich panel structure, a layer of hollow balls is evenly laid on the lower panel and vibrated to form a core layer of the sandwich panel structure, and another layer of carbon fiber cloth is placed on the core layer as an upper panel of the sandwich panel structure to obtain the horizontal sandwich preform.

[0099] The thickness of the carbon fiber cloth in the horizontal sandwich preform described in step 3 is 2 mm;

[0100] The thickness of the hollow sphere layer in the horizontal sandwich preform described in step 3 is 10 mm;

[0101] 4. Preheating and metal matrix preparation:

[0102] The sandwich panel preform obtained in step 4 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;

[0103] The protective gas in step 4 is nitrogen, and the gas pressure is 5 MPa;

[0104] 5. Liquid metal infiltration:

[0105] The preheated preform obtained in step 4 is placed on the press table 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.

[0106] The pressure infiltration process in step 5 is as follows: the pressure is 10 MPa and the infiltration speed is 0.5 mm / s;

[0107] After the pressure impregnation in step 5 is completed, the holding pressure is 10 MPa and the holding time is 15 minutes;

[0108] The holding temperature in step 5 is 500° C. and the holding time is 10 h.

[0109] The cooling rate in step 5 is 15°C / min.

[0110] The bonding strength between the face sheet and the core layer of the aluminum-based porous composite sandwich panel prepared in Example 2 is 33.5 MPa, which is 4.4 times the adhesive bonding strength (7.6 MPa) of the comparative example.

[0111] Example 3

[0112] The integrated molding method of the aluminum-based porous composite sandwich panel of this embodiment is carried out according to the following steps:

[0113] 1. Weighing

[0114] Weigh 65% of hollow glass microspheres and the remainder of aluminum ingots by volume;

[0115] The aluminum ingot in step 1 is Al-12Si alloy; the mass fraction of Si in Al-12Si alloy is 12%

[0116] The average particle size of the hollow spheres in step 1 is 20 μm;

[0117] 2. Panel material preparation

[0118] Take the metal sheet cloth and cut it according to the design requirements, then remove impurities from the surface;

[0119] The metal plate in step 2 is made of Q235 steel;

[0120] The thickness of the metal plate in step 2 is 2 mm;

[0121] 3. Preparation of sandwich panel prefabricated body

[0122] The sandwich panel prefabricated body is a horizontal sandwich prefabricated body;

[0123] The horizontal sandwich preform is prepared by laying a layer of metal plate on the bottom of a steel mold as a lower panel of a sandwich panel structure, evenly laying a layer of hollow balls on the lower panel and vibrating them to form a core layer of the sandwich panel structure, and placing another layer of metal plate on the core layer as an upper panel of the sandwich panel structure to obtain the horizontal sandwich preform;

[0124] The metal plate surface of the horizontal sandwich preform 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;

[0125] The thickness of the hollow sphere layer in the horizontal sandwich preform described in step 3 is 20 mm;

[0126] 4. Preheating and metal matrix preparation:

[0127] The sandwich panel preform obtained in step 4 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;

[0128] The protective gas in step 4 is helium, and the gas pressure is 5 MPa;

[0129] 5. Liquid metal infiltration:

[0130] The preheated preform obtained in step 4 is placed on the press table 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.

[0131] The pressure infiltration process in step 5 is as follows: the pressure is 5 MPa and the infiltration speed is 1 mm / s;

[0132] After the pressure impregnation in step 5 is completed, the holding pressure is 10 MPa and the holding time is 5 minutes;

[0133] The holding temperature in step 5 is 550° C. and the holding time is 15 h.

[0134] The cooling rate in step 5 is 10°C / min.

[0135] The bonding strength between the face sheet and the core layer of the aluminum-based porous composite sandwich panel prepared in Example 3 was 29.8 MPa, which was 3.9 times the adhesive bonding strength (7.6 MPa) of the comparative example.

[0136] Comparative Example

[0137] The preparation of the aluminum-based porous composite sandwich panel by the gluing method in this comparative example is carried out according to the following steps:

[0138] 1. Material Preparation

[0139] 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;

[0140] The aluminum ingot in step 1 is Al-12Si alloy; the mass fraction of Si in Al-12Si alloy is 12%

[0141] The average particle size of the hollow spheres in step 1 is 20 μm;

[0142] The epoxy resin in step 1 is E-44, and the epoxy curing agent is 650, with a mass ratio of 1:1;

[0143] The metal plate in step 1 is made of Q235 steel;

[0144] The thickness of the metal plate in step 1 is 2 mm;

[0145] 2. Preparation of preforms of core layer aluminum-based porous composite materials

[0146] 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;

[0147] The protective atmosphere is argon gas, and the gas pressure is 0.1 MPa;

[0148] 3. Liquid metal infiltration:

[0149] The preheated preform obtained in step 2 is placed on the press table 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, it is cooled to room temperature and finally demolded;

[0150] The pressure infiltration process is as follows: the pressure is 10 MPa and the infiltration speed is 1 mm / s.

[0151] 4. Preparation of composite sandwich panels:

[0152] 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 firmly to ensure a firm bond; then, the composite sandwich panel is placed in an 80°C drying oven and kept warm for 2 hours, and then taken out to obtain the composite sandwich panel.

[0153] 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 following steps are involved: (1) Weigh the materials, weigh 40-70% of the hollow balls and the rest of the aluminum ingots according to the volume fraction; (2) Panel material preparation: take metal plates or carbon fiber cloth and cut them according to design requirements, and then remove impurities from the surface; (3) Preparation of sandwich panel preforms, which are prepared into horizontal sandwich preforms or vertical sandwich preforms; (4) Preheating and metal matrix preparation: placing the sandwich panel preform obtained in step (3) with the mold into a heating furnace, introducing a protective gas and preheating to obtain a preheated preform; then heating the aluminum ingot weighed in step (1) under the protective gas to a molten metal matrix; (5) Liquid metal infiltration: the preheated preform obtained in step (4) is placed on the press table 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.

2. The integrated molding method of aluminum-based porous composite sandwich panels according to claim 1, characterized in that: 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.

3. The integrated molding method of aluminum-based porous composite sandwich panels according to claim 1, characterized in that: The hollow balls described in step (1) are one or a combination of several of the following: hollow alumina balls, hollow glass microspheres, hollow fly ash balls, hollow silicon carbide balls, and expanded perlite.

4. The integrated molding method of aluminum-based porous composite sandwich panels according to claim 1, characterized in that: The preparation method of the horizontal sandwich preform described in step (3) is as follows: a layer of metal plate or carbon fiber cloth is flatly laid 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 vibrated as the core layer of the sandwich panel structure, and another layer of metal plate or carbon fiber cloth is placed on the core layer as the upper panel of the sandwich panel structure to obtain a horizontal sandwich preform.

5. The integrated molding method of aluminum-based porous composite sandwich panels according to claim 1, characterized in that: The preparation method of the vertical sandwich preform in step (3) is as follows: two metal plates are placed vertically in a steel mold, hollow balls are filled between the two metal plates and compacted by vibration to obtain a vertical sandwich preform.

6. The integrated molding method of aluminum-based porous composite sandwich panels according to claim 1, characterized in that: The molten metal matrix in step (5) is heated to 250 to 450° C. above its melting point.

7. The integrated molding method of aluminum-based porous composite sandwich panels according to claim 1, characterized in that: The pressure infiltration process described in step (5) is as follows: the pressure is 5-10 MPa, and the infiltration speed is 0.5-1 mm / s.

8. The integrated molding method of aluminum-based porous composite sandwich panels according to claim 1, characterized in that: 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.

9. The integrated molding method of aluminum-based porous composite sandwich panels according to claim 1, characterized in that: The temperature for heat preservation in step (5) is 500-600° C., and the heat preservation time is 10-20 hours.

10. The integrated molding method of aluminum-based porous composite sandwich panels according to claim 1, characterized in that: The cooling rate in step (5) is 10-20°C / min.

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