Continuous carbon fiber reinforced composite material with high lightning stroke resistance toughness

Abstract

The invention provides a high-lightning-stroke-resistant toughness continuous carbon fiber reinforced composite material, which is obtained by paving a plurality of layers of continuous carbon fiber resin prepregs and intercalation layers to obtain a preform and curing the preform through a conventional composite material molding process, each resin-based prepreg layer used in a preset layer number range close to the anti-lightning side is a first resin prepreg layer, the other resin-based prepreg layers are second resin prepreg layers, an intercalation is arranged between every two adjacent second resin prepreg layers, and the intercalation material is a micron conductive material with the surface density of 2-20 g / m < 2 >; wherein the resin in each resin-based prepreg layer is added with 2-10wt% of carbon nanomaterial, and the compressive strength of the rest resin-based prepreg layers after impact is higher than 250MPa. The composite material provided by the invention realizes integrated compounding of high lightning stroke resistance and high impact toughness. The anti-lightning performance of the composite material can meet the requirements of no internal layering and low fiber damage on the surface, and meanwhile, the compression strength CAI after impact can reach more than 200MPa.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and more specifically to a continuous carbon fiber reinforced composite material with high lightning resistance toughness. Background Art

[0002] At present, continuous carbon fiber reinforced resin-based composite materials are increasingly being used in the field of civil aviation. For example, Boeing 787, Airbus A380 and other aircraft use resin-based composite materials in large quantities. However, due to the inherent insulation of the resin, this type of material has insufficient conductivity. When struck by lightning, it cannot effectively evacuate the lightning current, resulting in serious damage to the interior and affecting the safety of the aircraft. Therefore, the solutions in the prior art are all aimed at lightning protection of this material. For example, the lightning protection of composite materials of existing aircraft is mainly achieved by covering the surface of the aircraft with a metal mesh. However, this protection method requires an additional surface paving process and brings about significant weight gain. In recent years, research on composite materials with high lightning resistance has been carried out both at home and abroad. This type of material does not require an additional conductive sacrificial layer, so the weight gain caused is very small, and the paving process of the additional conductive layer is reduced. It is hailed as the future lightning resistance composite material technology. In order to meet the application requirements, composite materials with good lightning resistance performance need to meet the following conditions: (1) no large area of ​​stratification occurs under simulated lightning conditions; (2) no large number of fiber breakage occurs under simulated lightning conditions; (3) the material has a low damage depth (usually ≤0.3mm).

[0003] Another concern of composite materials in aircraft applications is the low-speed impact resistance of the materials. Low-speed impact can cause interlayer delamination of composite materials, resulting in a significant decrease in the compressive strength of composite materials, which will affect flight safety. Improving the toughness of composite materials can effectively improve the impact resistance of composite materials. The main indicator for evaluating the impact resistance of composite materials is the post-impact compressive strength (CAI). According to the literature (Science and Technology Review, 2018, 36(19): 52-63), the CAI of basic epoxy resin-based composite materials is generally 100-170MPa, the CAI of the first-generation tough epoxy resin-based composite materials is about 170-250MPa, and the CAI of the second-generation high-toughness epoxy resin-based composite materials can reach 250-315MPa. At present, most aircraft are still using the first or second generation tough composite materials. When the CAI of the composite material reaches 200MPa, it can meet the application of some domestic occasions.

[0004] Solving the problem of composite materials' lightning damage resistance is mainly achieved by improving the electrical conductivity of the composite materials. Typical methods include: (1) resin modification, such as introducing conductive carbon nanomaterials such as carbon nanotubes into the resin. (2) interlayer modification, such as introducing buckypaper, carbon nanotube film, nickel-plated carbon fiber felt and other materials into the interlayer, which have improved the electrical conductivity and lightning resistance. However, the use of buckypaper, carbon nanotube film, nickel-plated carbon fiber felt or serious degradation of the interlayer interface leads to a decrease in material performance or serious surface damage of the composite material, which actually fails to meet the application requirements of low lightning damage. At present, the toughness of the materials prepared by the above methods in the prior art is difficult to improve. Typically, the post-impact compressive strength (CAI) is 150-170 MPa, which does not meet the requirements. In addition, there is a conflict between electrical conductivity and toughness (especially CAI). Modification of electrical conductivity, especially modification with high content of conductive nanomaterials, often has a serious negative effect on the toughness of the material.

[0005] In order to simultaneously improve the conductivity and toughness of composite materials, academia and industry have conducted a lot of research. Typically, for example, a highly conductive modified toughening layer is inserted between layers. The conductivity of such modified composite materials is significantly improved, and the lightning protection performance is also improved. However, such materials either still have severe delamination and fiber breakage after lightning strikes, or the interlayer interface performance is poor, which is similar to the above-mentioned interlayer modification technical solution, so it cannot meet application requirements. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] The technical problem to be solved by the present invention is that it is difficult for existing composite materials to have both high lightning resistance and high toughness.

[0008] (II) Technical solution

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] The present invention provides a continuous carbon fiber reinforced composite material with high lightning strike toughness. The composite material has a connection side for connecting to an aircraft and a lightning strike resistant side away from the aircraft. The composite material is obtained by paving a preform of multiple layers of continuous carbon fiber resin prepreg and an intercalation layer, and is obtained by a curing molding process. Each resin-based prepreg layer within a preset number of layers of the composite material close to the lightning strike resistant side is a first resin prepreg layer, and the remaining resin-based prepreg layers are second resin prepreg layers. The first resin prepreg layer and the second resin prepreg layer are sequentially stacked and superimposed in a thickness direction. The intercalation layer is provided between two adjacent layers of the second resin prepreg layer. The material of the intercalation layer is a micron conductive material, and the surface density of the micron conductive material is 2 to 20 g / m 2; Wherein, the value of the preset layer number range N satisfies: 4≤N≤10 and N is a positive integer, 2 to 10 wt% of carbon nanomaterials are added to each layer of the first resin prepreg layer, and the performance of the second resin prepreg layer should satisfy: the post-impact compressive strength of the composite material prepared entirely by the second resin prepreg layer is higher than 250 MPa.

[0011] Preferably, the carbon nanomaterial includes at least one of carbon nanotubes, graphene, carbon nanofibers, and carbon black.

[0012] Preferably, the micron conductive material includes at least one of carbon fiber powder and graphite powder.

[0013] Preferably, when the micron conductive material comprises carbon fiber powder, the length of the carbon fiber powder is 50-200 μm; when the micron conductive material comprises graphite powder, the graphite powder has a particle size of 20-50 μm and a surface density of 3-15 g / m 2 .

[0014] Preferably, the micron conductive material is metal-plated carbon fiber powder.

[0015] Preferably, the length of the metal-coated carbon fiber powder is 50 to 200 μm, and the surface density is 8 to 20 g / m 2 .

[0016] Preferably, the micron conductive material is carbon fiber felt.

[0017] Preferably, the surface density of the carbon fiber felt is 2 to 10 g / m 2 .

[0018] Preferably, the thickness-wise electrical conductivity of the continuous carbon fiber reinforced composite material with high lightning strike toughness is not less than 0.2 S / cm.

[0019] (III) Beneficial effects

[0020] The above technical solution of the present invention has at least the following advantages:

[0021] In the present invention, 2-10wt% of carbon nanomaterials are added to the first prepreg layer near the lightning-resistant side of the composite material. The carbon nanomaterials can construct extremely high-density conductive paths in the resin matrix, thereby achieving highly dispersed lightning Joule heat effect. The second resin prepreg layer has a post-impact compression strength higher than 250MPa, and it has high toughness. An intercalation layer is provided between two adjacent layers of the second resin prepreg layer, and the intercalation material is a micron conductive material, which can assist in reducing the lightning Joule heat effect, thereby making the second resin prepreg layer have a certain lightning resistance while having high toughness performance. The composite material has good lightning resistance, and there is no internal stratification after lightning strike in the 2A zone. The lightning damage is mainly manifested as mild ablation damage of the first layer and small area of ​​second layer damage. In addition, the composite material has high toughness, and the post-impact compression strength CAI reaches more than 200MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic structural diagram of a continuous carbon fiber reinforced composite material with high lightning resistance toughness provided by an embodiment of the present invention.

[0024] Figure 2 The surface damage of the test plates of Example 1 and Comparative Example 4 provided by the present invention after being struck by lightning in zone 2A.

[0025] Figure 3 It is a schematic diagram of the relationship between the number of plies with high carbon nanomaterial content and the lightning delamination area used in two types of composite materials with different thickness and conductivity provided in an embodiment of the present invention.

[0026] Figure 4 Schematic diagram of the relationship between the amount of interlayer micron conductive material provided by an embodiment of the present invention and the CAI of the CCF800 / AC631 composite material.

[0027] The reference numerals in the figures are:

[0028] 1. Insertion layer; 2. First prepreg layer; 3. Second prepreg layer. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly located on the other element or indirectly located on the other element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element.

[0031] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention, and do not indicate that a device or element must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating relative importance or indicating the number of technical features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The specific implementation of the present invention is described in more detail below in conjunction with specific embodiments:

[0033] like Figure 1 As shown, an embodiment of the present invention provides a continuous carbon fiber reinforced composite material with high lightning resistance toughness. The composite material has a connection side for connecting to an aircraft and a lightning resistance side away from the aircraft. The composite material is obtained by paving a preform of multiple layers of continuous carbon fiber resin prepreg and intercalation layers, and is obtained by a curing molding process. Each resin-based prepreg layer within a preset number of layers of the composite material close to the lightning resistance side is a first resin prepreg layer 2, and the remaining resin-based prepreg layers are second resin prepreg layers 3. The first resin prepreg layer 2 and the second resin prepreg layer 3 are stacked in sequence along the thickness direction. An intercalation layer 1 is provided between two adjacent layers of the second resin prepreg layer 3. The material of the intercalation layer 1 is a micron conductive material, and the surface density of the micron conductive material is 2 to 20 g / m 2 ; Wherein, the value of the preset layer range N satisfies: 4≤N≤10 and N is a positive integer, 2-10wt% of carbon nanomaterials are added to each first resin prepreg layer 2, and the performance of the second resin prepreg layer should satisfy: the post-impact compression strength of the composite material prepared entirely from the second resin prepreg layer is higher than 250MPa. It should be noted that when the preset layer range N is 4, it means that each resin-based prepreg layer within the 4-layer range of the composite material close to the lightning protection side is the first resin prepreg layer 2, and when the preset layer range N is 10, it means that each resin-based prepreg layer within the 10-layer range of the composite material close to the lightning protection side is the first resin prepreg layer 2.

[0034] In one embodiment, the carbon nanomaterial includes at least one of carbon nanotubes, graphene, carbon nanofibers, and carbon black.

[0035] In one embodiment, the micron conductive material includes at least one of carbon fiber powder and graphite powder. When the micron conductive material includes carbon fiber powder, the length of the carbon fiber powder is 50 to 200 μm, and when the micron conductive material includes graphite powder, the graphite powder has a particle size of 20 to 50 μm and a surface density of 3 to 15 g / m 2 .

[0036] In one embodiment, the micron conductive material is metal-coated carbon fiber powder. The metal-coated carbon fiber powder has a length of 50 to 200 μm and a surface density of 8 to 20 g / m 2 .

[0037] In one embodiment, the micron conductive material is carbon fiber felt. The surface density of the carbon fiber felt is 2 to 10 g / m 2 .

[0038] In one of the embodiments, the thickness conductivity of the continuous carbon fiber reinforced composite material with high lightning resistance toughness is not less than 0.2 S / cm.

[0039] The following are specific examples and comparative examples provided in this application, and their corresponding test data:

[0040] Embodiment 1: The implementation process of this embodiment is as follows:

[0041] (1-1) A unidirectional ZT7H carbon fiber reinforced high-content carbon nanotube modified epoxy resin prepreg was made by the Composite Materials Center of the Manufacturing Institute. The single-layer cured thickness was 0.125 mm and the single-layer fiber surface density was 135 g / m 2 , the carbon nanotube content in the resin is 7.2wt%, and the resin content is 32.2wt%. 16 prepregs of 300mm×300mm are cut as the first resin prepreg layer 2, of which 8 have a fiber orientation of 0° and 8 have a fiber orientation of 45°.

[0042] (1-2) Take a unidirectional ZT7H carbon fiber reinforced high-toughness epoxy resin prepreg (ZT7H / AC531), a product of AVIC Composite Materials Co., Ltd., with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m 2 , the CAI of the prepreg is 300 MPa. 32 sheets of 300 mm×300 mm prepreg are cut as the second resin prepreg layer 3, of which 16 sheets have a fiber orientation of 0° and 16 sheets have a fiber orientation of 45°.

[0043] (1-3) Take carbon fiber powder, carbon fiber T700, with an average length of 0.1 mm, as the material for forming the intercalation layer 1, and evenly sprinkle the carbon fiber powder on the surface of each ZT7H / AC531 by a powder sprinkling method, with an amount of 10 g / m 2 , hot roller compaction was performed to obtain ZT7H / AC531C prepreg with carbon fiber powder attached to the surface (C represents conductive particle modification, the same below).

[0044] (1-4) The prepregs of (1-1) and (1-3) are laid in the following order: (1) for lightning strike test, the ply is ([45,0,-45,90]2)([90,-45,0,45]2); (2) for CAI test, the ply is ([45,0,-45,90]2)([45,0,-45,90]2[90,-45,0,45]4). Then, the prepregs are cured according to the standard curing process of ZT7H / AC531, cooled to below 60°C, and demolded to obtain a ZT7H reinforced epoxy resin composite material with high lightning strike toughness. In the above-mentioned ply sequence, the first group is the carbon nanotube modified prepreg in (1-1), and the second group is the ZT7H / AC531C prepreg with carbon fiber powder attached to the surface in (1-3). The first group of plies and the second group of plies refer to the plies in the first bracket and the plies in the second bracket of the ply sequence, respectively, and the same applies hereinafter.

[0045] After testing, the carbon fiber composite material with high lightning resistance toughness obtained in this embodiment has good lightning resistance performance, the thickness conductivity of the composite material is 0.607S / cm, and the post-impact compression strength of the composite material is 212MPa.

[0046] Embodiment 2:

[0047] The implementation process of this embodiment is as follows:

[0048] (2-1) Take a unidirectional CCF800 carbon fiber reinforced high-content carbon nanotube modified epoxy resin prepreg, which is made by the Composite Materials Center of the Manufacturing Institute. The single-layer cured thickness is 0.125 mm and the single-layer fiber surface density is 135 g / m 2 The carbon nanotube content in the resin is 2.2wt%, the graphene content is 3.1wt%, and the resin content is 33.4wt%. Eight prepregs of 300mm×300mm are cut as the first resin prepreg layer 2, of which four have a fiber orientation of 0° and four have a fiber orientation of 45°.

[0049] (2-2) Take a unidirectional CCF800 carbon fiber reinforced high-toughness epoxy resin prepreg (CCF800 / 1316), a product of AVIC Composite Materials Co., Ltd., with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m 2, the CAI of the prepreg is 260 MPa. 40 sheets of 300 mm×300 mm prepreg are cut as the second resin prepreg layer 3, of which 20 sheets have a fiber orientation of 0° and 20 sheets have a fiber orientation of 45°.

[0050] (2-3) Take graphite powder with an average diameter of 37 μm as the material for forming intercalation layer 1, and evenly sprinkle the graphite powder on the surface of each CCF800 / 1316 by a powder sprinkling method, with an amount of 8 g / m 2 , hot roller compaction was used to obtain CCF800 / 1316C prepreg with graphite powder on the surface.

[0051] (2-4) The above materials are laid in the following order: (1) for lightning strike test, the ply is ([45,0,-45,90])([45,0,-45,90][90,-45,0,45]2); (2) for CAI test, the ply is ([45,0,-45,90])([45,0,-45,90]3[90,-45,0,45]4). Then, the materials are cured according to the standard curing process of CCF800 / 1316, cooled to below 60°C, and demolded to obtain CCF800 reinforced epoxy resin composite materials with high lightning strike toughness. In the above ply order, the first group is carbon nanotube modified prepreg, and the second group is CCF800 / 1316C prepreg with graphite powder attached to the surface.

[0052] After testing, the high lightning resistance toughness carbon fiber composite material obtained in this embodiment has good lightning resistance performance, the thickness conductivity of the composite material is 0.901S / cm, and the post-impact compression strength of the composite material is 231MPa.

[0053] Embodiment 3:

[0054] The implementation process of this embodiment is as follows:

[0055] (3-1) Take a unidirectional CCF800 carbon fiber reinforced high-content carbon nanomaterial modified epoxy resin prepreg, which is made by the Composite Materials Center of the Manufacturing Institute. The single-layer cured thickness is 0.125 mm and the single-layer fiber surface density is 135 g / m 2 The carbon nanotube content in the resin is 2.3wt%, and the resin content is 32.1wt%. 12 prepregs of 300mm×300mm are cut as the first resin prepreg layer 2, of which 6 have a fiber orientation of 0° and 6 have a fiber orientation of 45°.

[0056] (3-2) Take a unidirectional CCF800 carbon fiber reinforced high-toughness epoxy resin prepreg (CCF800 / AC531), a product of AVIC Composite Materials Co., Ltd., with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m2 , the CAI of the prepreg is 300 MPa. 36 sheets of 300 mm×300 mm prepreg are cut as the second resin prepreg layer 3, of which 18 sheets have a fiber orientation of 0° and 18 sheets have a fiber orientation of 45°.

[0057] (3-3) Cut 36 sheets of 300 mm × 300 mm carbon fiber felt as intercalation layer 1. The fiber used in the carbon fiber felt is CCF800 with a surface density of 5 g / m 2 .

[0058] (3-4) The above materials were laid in the following order: (1) for lightning strike test, the ply was ([45,0,-45,90,45,0])([I,-45,I,90,I,90,I,-45,I,0,I,45,I,90,I,-45,I,0,I,45]); (2) for CAI test, the ply was ([45,0,-45,90,45,0])([I,-45,I,90][I,45,I,0,I,-45,I,90]2[I,90,I,-45,I,0,I,45]4). Then, the materials were cured according to the standard curing process of CCF800 / AC531, cooled to below 60°C and demolded to obtain CCF800 reinforced epoxy resin composite materials with high lightning strike toughness. In the above-mentioned plying sequence, the first group is carbon nanotube modified prepreg, the second group is CCF800 / AC531C, and I represents an inserted carbon fiber felt.

[0059] After testing, the high lightning resistance toughness carbon fiber composite material obtained in this embodiment has good lightning resistance performance, the thickness conductivity of the composite material is 0.328S / cm, and the post-impact compression strength of the composite material is 237MPa.

[0060] Embodiment 4:

[0061] The implementation process of the technical solution of the present invention is as follows:

[0062] (4-1) Take a unidirectional CCF800 carbon fiber reinforced high-content carbon nanotube modified bismaleimide resin prepreg, which is made by the Composite Materials Center of the Manufacturing Institute. The single-layer cured thickness is 0.125 mm and the single-layer fiber surface density is 135 g / m 2 , the content of graphene in the resin is 4.2wt%, the content of carbon nanofiber is 1wt%, and the content of resin is 33.5wt%. 20 prepregs of 300mm×300mm are cut as the first resin prepreg layer 2, of which 10 have a fiber orientation of 0° and 10 have a fiber orientation of 45°.

[0063] (4-2) Take a unidirectional CCF800 carbon fiber reinforced high-toughness bismaleimide resin prepreg (CCF800 / AC631), a product of AVIC Composite Materials Co., Ltd., with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m 2 , the CAI of the prepreg is 305 MPa. 44 prepregs of 300 mm×300 mm are cut, of which 22 have a fiber orientation of 0° as the second resin prepreg layer 3 and 22 have a fiber orientation of 45°.

[0064] (4-3) Take nickel-plated carbon fiber powder, carbon fiber T700, with an average length of 0.1 mm and a nickel content of 60 wt%, as the material for forming the intercalation layer 1, and evenly sprinkle the carbon fiber powder on the surface of each CCF800 / AC631 prepreg by a powder sprinkling method, with an amount of 17.5 g / m 2 , hot roller compaction was used to obtain CCF800 / AC631C prepreg with nickel-plated carbon fiber powder on the surface.

[0065] (4-4) The above materials are laid in the following order: (1) For the lightning strike test, the ply is ([45,0,-45,90]2[45,0])([-45,90][45,0,-45,90][90,-45,0,45]4); (2) For the CAI test, the ply is ([45,0,-45,90]2[45,0])([-45,90][45,0,-45,90][90,-45,0,45]4) (same as the lightning strike test, 32 layers are used). Then, the materials are cured according to the standard curing process of CCF800 / AC631, cooled to below 60°C, demolded and taken out to obtain a CCF800 reinforced bismaleimide resin composite material with high lightning strike toughness. In the above-mentioned ply sequence, the first group is graphene-modified prepreg, and the second group is CCF800 / AC631C with nickel-plated carbon fiber powder attached to the surface.

[0066] After testing, the high lightning resistance toughness carbon fiber composite material obtained in this embodiment has good lightning resistance performance, the thickness conductivity of the composite material is 0.527S / cm, and the post-impact compression strength of the composite material is 245MPa.

[0067] Embodiment 5:

[0068] The implementation process of this embodiment is as follows:

[0069] (5-1) Take a unidirectional CCF800 carbon fiber reinforced high-content carbon nanotube modified bismaleimide resin prepreg, which is made by the Composite Materials Center of the Manufacturing Institute. The single-layer cured thickness is 0.125 mm and the single-layer fiber surface density is 135 g / m 2, the carbon nanotube content in the resin is 2.7wt%, the carbon black content is 5.2wt%, and the resin content is 34.1wt%. 16 prepregs of 300mm×300mm are cut, of which 8 have a fiber orientation of 0° and 8 have a fiber orientation of 45°.

[0070] (5-2) Take a unidirectional CCF800 carbon fiber reinforced high-toughness bismaleimide resin prepreg (CCF800 / 5429), a product of AVIC Composite Materials Co., Ltd., with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m 2 , the CAI of the prepreg is 255 MPa. 48 prepregs of 300 mm×300 mm were cut, of which 12 had a fiber orientation of 0° and 12 had a fiber orientation of 45°.

[0071] (5-3) Cut 48 pieces of 300mm×300mm carbon fiber felt, the carbon fiber is T700, and the surface density is 10g / m 2 .

[0072] (5-4) The above materials are laid in the following order: (1) for lightning strike test, the ply is ([45,0,-45,90]2)([I,45,I,0,I,-45,I,90]2[I,90,I,-45,I,0,I,45]4); (2) for CAI test, the ply is ([45,0,-45,90]2)([I,45,I,0,I,-45,I,90]2[I,9 0,I,-45,I,0,I,45]4 (same as the lightning test, 32 layers are used). Then, the material is cured according to the standard curing process of CCF800 / 5429, cooled to below 60°C, demolded and taken out to obtain a CCF800 reinforced bismaleimide resin composite material with high lightning resistance toughness. In the above ply order, the first group is carbon nanomaterial modified prepreg, the second group is CCF800 / 5429 prepreg, and I represents a carbon fiber felt inserted.

[0073] The high lightning resistance toughness carbon fiber composite material obtained in this embodiment has good lightning resistance performance, the thickness conductivity of the composite material is 0.418S / cm, and the post-impact compression strength of the composite material is 215MPa.

[0074] Embodiment 6:

[0075] The implementation process of this embodiment is as follows:

[0076] (6-1) Take a unidirectional CCF800 carbon fiber reinforced high-content carbon nanotube and graphene co-modified epoxy resin prepreg, which is made by the Composite Materials Center of the Manufacturing Institute. The single-layer cured thickness is 0.125 mm and the single-layer fiber surface density is 135 g / m 2, the carbon nanotube content in the resin is 1.2wt%, the graphene content is 0.8wt%, and the resin content is 32.7wt%. 16 prepregs of 300mm×300mm are cut as the first resin prepreg layer 2, of which 8 have a fiber orientation of 0° and 8 have a fiber orientation of 45°.

[0077] (6-2) Take a unidirectional CCF800 carbon fiber reinforced high-toughness epoxy resin prepreg (CCF800 / 1316), a product of AVIC Composite Materials Co., Ltd., with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m 2 , the CAI of the prepreg is 260 MPa. 32 sheets of 300 mm×300 mm prepreg are cut as the second resin prepreg layer 3, of which 16 sheets have a fiber orientation of 0° and 16 sheets have a fiber orientation of 45°.

[0078] (6-3) Take graphite powder with an average diameter of 24 μm as the material for forming intercalation layer 1, and evenly sprinkle the graphite powder on the surface of each CCF800 / 1316 by a powder sprinkling method, with an amount of 15 g / m 2 , hot roller compaction was used to obtain CCF800 / 1316C prepreg with graphite powder on the surface.

[0079] (6-4) The above materials are laid in the following order: (1) for lightning strike test, the ply is ([45,0,-45,90]2)([90,-45,0,45]2); (2) for CAI test, the ply is ([45,0,-45,90]2)([45,0,-45,90]2[90,-45,0,45]4). Then, the materials are cured according to the standard curing process of CCF800 / 1316, cooled to below 60°C, and demolded to obtain CCF800 reinforced epoxy resin composite materials with high lightning strike toughness. In the above ply order, the first group is carbon nanotube modified prepreg, and the second group is CCF800 / 1316C prepreg with graphite powder attached to the surface.

[0080] After testing, the high lightning resistance toughness carbon fiber composite material obtained in this embodiment has good lightning resistance performance, the thickness conductivity of the composite material is 0.730S / cm, and the post-impact compression strength of the composite material is 207MPa.

[0081] Embodiment 7:

[0082] The implementation process of this embodiment is as follows:

[0083] (7-1) Take a unidirectional CCF800 carbon fiber reinforced high-content multi-carbon nanomaterial modified epoxy resin prepreg, which is made by the Composite Materials Center of the Manufacturing Institute. The single-layer cured thickness is 0.125 mm and the single-layer fiber surface density is 136 g / m2 , the carbon nanotube content in the resin is 3.0wt%, the graphene content is 5.0wt%, the carbon black content is 2.0wt%, and the total resin content is 34.2wt%. 16 prepregs of 300mm×300mm are cut as the first resin prepreg layer 2, of which 8 have a fiber orientation of 0° and 8 have a fiber orientation of 45°.

[0084] (7-2) Take a unidirectional CCF800 carbon fiber reinforced high-toughness epoxy resin prepreg (CCF800 / 1316), a product of AVIC Composite Materials Co., Ltd., with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m 2 , the CAI of the prepreg is 260 MPa. 32 sheets of 300 mm×300 mm prepreg are cut as the second resin prepreg layer 3, of which 16 sheets have a fiber orientation of 0° and 16 sheets have a fiber orientation of 45°.

[0085] (7-3) Cut 48 pieces of 300mm×300mm carbon fiber felt, the carbon fiber is T800, and the surface density is 2g / m 2 .

[0086] (7-4) The above materials are laid in the following order: (1) for lightning strike test, the ply is ([45,0,-45,90]2)([I,90,I,-45,I,0,I,45]2); (2) for CAI test, the ply is ([45,0,-45,90]2)([I,45,I,0,I,-45,I,90]2[I,90,I,-45,I,0,I,45]4 (32 layers are used). Then, the materials are cured according to the standard curing process of CCF800 / 1316, cooled to below 60°C, demolded and taken out to obtain CCF800 reinforced epoxy resin composite materials with high lightning strike toughness. In the above ply order, the first group is carbon nanomaterial modified prepreg, the second group is CCF800 / 5429 prepreg, and I represents a carbon fiber felt inserted.

[0087] The high lightning resistance toughness carbon fiber composite material obtained in this example has good lightning resistance performance, the thickness conductivity of the composite material is 0.382S / cm, and the post-impact compression strength of the composite material is 221MPa.

[0088] The implementation process of this comparative example is as follows:

[0089] (D1-1) A unidirectional ZT7H carbon fiber reinforced high-content carbon nanomaterial modified epoxy resin prepreg was made by the Composite Materials Center of the Manufacturing Institute. The single-layer cured thickness was 0.125 mm and the single-layer fiber surface density was 135 g / m 2, the carbon nanotube content in the resin is 7.2wt%, and the resin content is 32.2wt%. 64 prepregs of 300mm×300mm are cut, of which 32 have a fiber orientation of 0° and 32 have a fiber orientation of 45°.

[0090] (D1-2) The above materials are laid in a quasi-isotropic order: (a) [45, 0, -45, 90, 45] 2s , used for lightning strike experiments; (b) [45, 0, -45, 90, 45] 4s , used for post-impact compression strength test. Then, the prepreg is cured according to the standard curing process, i.e., 135℃ / 1h+180℃ / 2h, cooled to below 60℃, demoulded and taken out to obtain a high lightning resistance composite material.

[0091] The high lightning resistance toughness carbon fiber composite material obtained in this comparative example has good lightning resistance performance, the thickness conductivity of the composite material is 0.337S / cm, and the post-impact compression strength of the composite material is 179MPa.

[0092] The implementation process of this comparative example is as follows:

[0093] (D2-1) Take a unidirectional CCF800 carbon fiber reinforced high-toughness bismaleimide resin prepreg (CCF800 / AC631), a product of the Institute's Composites Center, with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m 2 , the CAI of the prepreg is 300 MPa. 64 prepregs of 300 mm×300 mm were cut, of which 32 had a fiber orientation of 0° and 32 had a fiber orientation of 45°.

[0094] (D2-2) Lay the above materials in the following order: (a) [45, 0, -45, 90, 45, 0] 2s , used for lightning strike experiments; (b) [45,0,-45,90,45,0] 4s , used for post-impact compression strength test. Then, it is cured according to the standard curing process of CCF800 / AC531, cooled to below 60°C, demoulded and taken out, and a high-toughness CCF800 reinforced bismaleimide resin composite material is obtained.

[0095] The high lightning resistance toughness carbon fiber composite material obtained in this comparative example was severely damaged by lightning, the thickness conductivity of the composite material was 0.0053S / cm, and the post-impact compression strength of the composite material was 302MPa.

[0096] The implementation process of this comparative example is as follows:

[0097] (D3-1) Take a unidirectional CCF800 carbon fiber reinforced high-toughness bismaleimide resin prepreg (CCF800 / AC631), a product of the Institute's Composites Center, with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m 2 , the CAI of the prepreg was tested to be 305 MPa. 64 prepregs of 300 mm×300 mm were cut, of which 32 had a fiber orientation of 0° and 32 had a fiber orientation of 45°.

[0098] (D2-2) Cut 63 pieces of carbon fiber felt of 300mm×300mm, the carbon fiber is T700, and the surface density is 8g / m 2 .

[0099] (D2-3) The above materials are laid in the following order: (1) For lightning strike experiment, the layer is [45,0,-45,90,45,0] 2s , one layer of carbon fiber felt is inserted between all layers; (2) For CAI test, the ply is [45,0,-45,90,45,0] 4s , one layer of carbon fiber felt is inserted between all layers. Then, it is cured according to the standard curing process of CCF800 / AC631, cooled to below 60°C, demoulded and taken out, and a CCF800 reinforced bismaleimide resin composite material with toughness and modified for lightning resistance is obtained.

[0100] The lightning-resistant modified tough carbon fiber composite material obtained in this comparative example suffered serious lightning damage, with 3 damaged layers and a delamination area of ​​about 8600 mm2. The thickness-wise conductivity of the composite material was 0.692 S / cm.

[0101] Comparative Example 4:

[0102] The implementation process of this comparative example is as follows:

[0103] (D4-1) Take a unidirectional CCF800 carbon fiber reinforced high-toughness bismaleimide resin prepreg (CCF800 / AC631), a product of the Institute's Composites Center, with a single-layer cured thickness of 0.125 mm and a single-layer fiber surface density of 135 g / m 2 , the CAI of the prepreg is 300 MPa. 48 prepregs of 300 mm×300 mm were cut, of which 24 had a fiber orientation of 0° and 24 had a fiber orientation of 45°.

[0104] (D4-2) All the above prepreg surfaces are coated with nickel-plated carbon fiber powder, with a coating surface density of 17.5 g / m 2 ,CCF800 / AC631C with a layer of nickel-plated carbon fiber powder on the surface was obtained by hot ironing.

[0105] (D4-3) The above CCF800 / AC631C prepreg was laid in the following order: (1) For lightning strike test, the ply was [45, 0, -45, 90, 45, 0] 2s ; (2) For CAI test, the layer is [45,0,-45,90,45,0] 4s Then, the composite material is cured according to the standard curing process of CCF800 / AC631, cooled to below 60°C, and demoulded to obtain a CCF800 reinforced bismaleimide resin composite material with toughness and lightning resistance modification.

[0106] The lightning-resistant modified tough carbon fiber composite material obtained in this comparative example was severely damaged by lightning, with 3 damaged layers and a delamination area of ​​about 10700 mm 2 The thickness conductivity of the composite material is 0.539S / cm.

[0107] Table 1 summarizes the material parameters and composite material properties of the above examples and comparisons. The definition standard of the damage condition in the composite material property item in Table 1 refers to the damage condition of the fiber layer analyzed visually and under a microscope after the fiber hairs in the resin vaporized and coked areas on the surface of the composite material board after the lightning strike are fully scraped off; the definition standard of the delamination area in the composite material property item in Table 1 refers to the joint analysis of the non-destructive C-scan test and the destructive cross-sectional microscopic analysis test after the fiber in the resin vaporized and coked areas on the surface of the composite material board after the lightning strike is fully scraped off.

[0108] Table 1. Material parameters of various embodiments and comparative examples

[0109]

[0110]

[0111] In the present invention, by adding a high content of carbon nanomaterials to the first resin prepreg layer 2, the carbon nanomaterials form an extremely high density conductive path in the resin, achieving the purpose of highly dispersing the Joule heat effect of lightning strikes. As a comparison (Comparative Examples 3 and 4), the use of micron materials for modification cannot meet the requirements of low damage from lightning strikes. The content of carbon nanomaterials should meet 2-10wt%. When it is lower than 2%, the conductive paths formed by the carbon nanomaterials between the layers are too few and insufficient to form a high-density conductive network that meets the requirements. When the content of carbon nanomaterials is higher than 10wt%, the conductive paths between the layers have been fully formed. Further increasing the content of carbon nanomaterials cannot effectively improve the lightning resistance of the composite material, but will cause a decrease in other properties of the material.

[0112] In the scheme of the present invention, the latter layers of the composite material are designed to reduce the Joule heating effect of lightning strikes and provide high toughness at the same time. By arranging an intercalation layer of micron conductive material between the layers of the second resin prepreg layer 3 with high toughness, the second resin prepreg layer 3 maintains high toughness while also reducing the Joule heating effect of lightning strikes, thereby avoiding the generation of internal stratification when two prepregs (the first resin prepreg layer 2 and the second resin prepreg layer 3) are laid together. As a comparison (Comparative Example 1), when only nano-conductive materials such as carbon nanotubes, graphene, etc. are introduced into the first resin prepreg layer 2 to form a higher conductive path density, the toughness performance of the composite material cannot be maintained; directly using high-toughness prepreg without conductive modification (Comparative Example 2), the latter layers lack effective conductive paths, which will lead to excessively high Joule heating effects of lightning strikes in these layers, and lightning strikes will cause serious stratification damage in these layers. The corresponding test pieces of the composite materials of Example 1 and Comparative Example 4 after the 2A zone lightning strike test are shown in the figure. Figure 2 As shown (Note: the test board of Example 1 has been cleaned of surface damage and raised fibers, and the test board of Comparative Example 4 has been cleaned of obvious delamination areas).

[0113] In order to achieve the requirement of low lightning damage to composite materials, fully suppress the occurrence of internal delamination and reduce the damage to the superficial fiber, it is necessary to design the ply of the composite materials. The lightning damage delamination characteristics of composite materials with different plying methods can be seen Figure 3 (The material system adopts the unidirectional ZT7H carbon fiber reinforced high-content carbon nanotube modified epoxy resin prepreg and the unidirectional ZT7H carbon fiber reinforced high-toughness epoxy resin prepreg (ZT7H / AC531) in Example 1 and Comparative Example 1.) z ) and processability, and the prepreg system used, so the material layer design needs to meet the needs of different prepregs. In general, the conductive modification scheme of the present invention can make the composite material σ z Above 0.2S / cm, Figure 3 It can be seen that for high σ z For the composite material group (σz ≥ 0.8S / cm), when the number of high-content carbon nanomaterial layers is less than 4, delamination may occur between the layers after the 2A zone lightning test, while when it is more than 4 layers, no delamination occurs; for low σ z Composite materials (0.2S / cm≥σ z ≥0.4S / cm), the number of high-content carbon nanomaterial prepreg layers reaches 10 to effectively avoid delamination inside the composite material. Therefore, the number of high-content carbon nanomaterial layers is preferably 4 to 12. When the number of layers is higher than 12, the lightning strike performance of the composite material is not improved, but the toughness performance is reduced.

[0114] We found that the amount of micron conductive material has a significant effect on the toughness and lightning resistance of the material. As the amount of micron conductive material increases, the toughness of the composite material shows a downward trend. Figure 4 The figure shows the change of CAI of an ultra-high toughness prepreg CCF800 / AC631 after inserting a micron conductive modified material between the layers as the amount of micron conductive material increases (see Comparative Examples 3 and 4 for the material system). It can be seen from the figure that for ultra-high toughness prepreg, in order to avoid a significant reduction in CAI, the amount of micron conductive modified material also needs to be controlled to 20g / m 2 In order to make the CAI of the composite material reach above 200MPa and meet the requirements of some applications, the CAI of the composite material prepared by all micron conductive modified high-toughness prepreg should be higher than 220MPa, and the CAI of the composite material prepared only by high-toughness prepreg should be higher than 250MPa, and the surface density of the micron conductive material should be controlled to 2-20g / m 2 .

[0115] In summary, through the arrangement of the above scheme, the first several layers of the composite material prepared by the present invention can highly disperse the Joule heating effect of lightning strike, and the latter several layers can effectively reduce the Joule heating effect of lightning strike and provide high toughness at the same time. The composite material has good lightning resistance, and there is no internal stratification after lightning strike in the 2A area. The lightning damage is mainly manifested as mild ablation damage of the first layer and small area of ​​second layer damage. In addition, the composite material has high toughness, and the compression strength CAI of the composite material after impact can reach more than 200MPa.

[0116] 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A continuous carbon fiber reinforced composite material with high lightning resistance toughness, characterized in that: The composite material has a connection side for connecting to an aircraft and a lightning protection side facing away from the aircraft. The composite material is obtained by paving a preform of multiple layers of continuous carbon fiber resin prepreg and intercalation layers, and is obtained through a curing molding process. Each resin prepreg layer within a preset layer number range N close to the lightning protection side of the composite material is a first resin prepreg layer, and the remaining resin-based prepreg layers are second resin prepreg layers. The first resin prepreg layer and the second resin prepreg layer are sequentially stacked and superimposed in the thickness direction. The intercalation layer is provided between two adjacent layers of the second resin prepreg layer. The material of the intercalation layer is a micron conductive material, and the surface density of the micron conductive material is 2 to 20 g / m 2 ; Among them, the value of the preset layer number range N satisfies: 4≤N≤10 and N is a positive integer, 2-10wt% of carbon nanomaterial is added to each layer of the first resin prepreg layer, and the performance of the second resin prepreg layer should satisfy: the post-impact compressive strength of the composite material prepared entirely by the second resin prepreg layer is higher than 250MPa.

2. The continuous carbon fiber reinforced composite material with high lightning resistance toughness according to claim 1, characterized in that: The carbon nanomaterial includes at least one of carbon nanotubes, graphene, carbon nanofibers, and carbon black.

3. The continuous carbon fiber reinforced composite material with high lightning resistance toughness according to claim 1, characterized in that: The micron conductive material includes at least one of carbon fiber powder and graphite powder.

4. The continuous carbon fiber reinforced composite material with high lightning resistance toughness as claimed in claim 3, characterized in that: When the micron conductive material includes carbon fiber powder, the length of the carbon fiber powder is 50-200 μm; when the micron conductive material includes graphite powder, the graphite powder has a particle size of 20-50 μm and a surface density of 3-15 g / m 2 .

5. The continuous carbon fiber reinforced composite material with high lightning resistance toughness according to claim 1, characterized in that: The micron conductive material is metal-plated carbon fiber powder.

6. The continuous carbon fiber reinforced composite material with high lightning resistance toughness as claimed in claim 5, characterized in that: The metal-coated carbon fiber powder has a length of 50 to 200 μm and a surface density of 8 to 20 g / m 2 .

7. The continuous carbon fiber reinforced composite material with high lightning resistance toughness according to claim 1, characterized in that: The micron conductive material is carbon fiber felt.

8. The continuous carbon fiber reinforced composite material with high lightning resistance toughness as claimed in claim 7, characterized in that: The surface density of the carbon fiber felt is 2 to 10 g / m 2 .

9. The continuous carbon fiber reinforced composite material with high lightning resistance toughness according to claim 1, characterized in that: The electrical conductivity in the thickness direction of the continuous carbon fiber reinforced composite material with high lightning resistance toughness is not less than 0.2S / cm.

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