Interlayer toughened carbon-glass hybrid composite material and preparation method thereof

Abstract

The invention relates to an interlayer toughened carbon-glass hybrid composite material and a preparation method thereof, and belongs to the technical field of composite material molding. The method comprises the steps that a carbon fiber layer and a glass fiber layer are laid in sequence, and in the laying process, a fiber web tire layer composed of chopped fibers is laid between the carbon fiber layer and the glass fiber layer, so that a laying layer structure is obtained; infiltrating the laminated structure with a resin material and curing to obtain an interlayer toughened carbon-glass hybrid composite material; wherein the carbon fiber layer comprises carbon fiber fabrics which are continuously laid, and the glass fiber layer comprises glass fiber fabrics which are continuously laid. A layer of fiber net tire is introduced between macroscopic heterogeneous laying layer interfaces of carbon fibers and glass fibers, and the damage mode of the material is converted into ductile damage from brittle layering by forming a modulus gradient transition area, so that the damage tolerance and reliability of the material are remarkably enhanced.

Description

Technical Field

[0001] This invention belongs to the field of composite material molding technology, specifically relating to an interlayer toughened carbon-glass hybrid composite material and its preparation method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Carbon fiber composites are widely used in many fields due to their lightweight and high strength, but they are expensive, have low elongation at break, and are prone to damage after impact. While glass fiber has relatively lower tensile strength and elastic modulus, its low cost, high elongation, and good vibration and impact energy absorption make it a good option for blending carbon and glass fibers to balance cost and performance. However, the modulus mismatch between carbon and glass fibers causes stress to concentrate at the macroscopic interface of the heterogeneous materials under stress, leading to brittle and catastrophic delamination. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an interlayer toughened carbon-glass hybrid composite material and its preparation method. A porous, flexible fiber mesh interlayer composed of short-cut random fibers is introduced between a rigid continuous carbon fiber layup and a relatively flexible continuous glass fiber layup to form a carbon-glass hybrid layup structure with a transition layer. The composite material is then obtained by resin impregnation and curing.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: Firstly, a method for preparing an interlayer toughened carbon-glass hybrid composite material includes the following steps: S1. Lay carbon fiber layer and glass fiber layer in sequence. During the laying process, lay a fiber mesh layer composed of short chopped fibers between the carbon fiber layer and the glass fiber layer to obtain the layup structure. S2. Impregnate the layered structure with resin material and cure it to obtain a carbon-glass hybrid composite material with interlayer toughening; The carbon fiber layer includes continuously laid carbon fiber fabric, and the glass fiber layer includes continuously laid glass fiber fabric.

[0006] Secondly, the interlayer toughened carbon-glass hybrid composite material prepared by the above-mentioned method is an interlayer toughened carbon-glass hybrid composite material.

[0007] The beneficial effects of this invention are as follows: 1. This invention constructs a modulus gradient transition zone, fundamentally improving stress concentration at the interface of heterogeneous materials: After curing, the fiber mesh layer forms a gradient transition zone with a modulus between the carbon fiber layer and the glass fiber layer. This structure can smooth the huge stress abrupt change caused by modulus mismatch between heterogeneous materials, fundamentally alleviating interface stress concentration and improving the reliability and durability of the structure under complex loads. The randomly distributed short chopped fibers in the mesh layer are partially embedded in the gaps between the upper and lower layers of fabric, forming a three-dimensional mechanical interlock, realizing three-dimensional stress transfer and crack pinning, far exceeding the intermolecular forces at the interface of pure resin. When the crack propagates, these fibers generate closing stress on the crack tip through the "fiber bridging" effect, forcing the crack to deflect and branch, and consuming a large amount of energy, thereby changing the interface failure mode from brittle fracture to ductile tearing.

[0008] 2. The interfacial properties and toughening effect of the carbon-glass hybrid composite material obtained by this invention are significantly improved: The most direct effect of this invention is a substantial improvement in the interlaminar properties of the composite material. Experimental data show that its interlaminar shear strength can be increased by 13.82%, and its ultimate load displacement can be increased by 13.51%. This means that the material transforms from a brittle failure mode prone to catastrophic delamination to a ductile failure mode with high damage tolerance, effectively suppressing the unstable propagation of cracks.

[0009] 3. Process-Friendliness and Cost-Effectiveness: This invention is perfectly compatible with existing mainstream molding processes such as vacuum casting, prepreg, and autoclave molding, with almost no increase in manufacturing complexity or time cost. Furthermore, the porous nature of the mesh layer facilitates resin transfer, improving resin impregnation efficiency. This method achieves a qualitative leap in interfacial performance at extremely low weight and cost, possessing extremely high engineering application value and cost-effectiveness. Attached Figure Description

[0010] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0011] Figure 1 This is a schematic diagram of the layered structure in Example 1.

[0012] Figure 2 The images show the surface damage morphology of the samples from Example 1 and Comparative Example 1, where (a) is Example 1 and (b) is Comparative Example 1.

[0013] Figure 3 This is a schematic diagram of the layered structure in Example 2.

[0014] The structure consists of: 1. Carbon fiber layer; 2. Fiber mesh layer; 3. Fiberglass layer. Detailed Implementation

[0015] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0016] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0017] One or more embodiments of the present invention provide a method for preparing an interlayer toughened carbon-glass hybrid composite material, comprising the steps of: S1. Lay carbon fiber layer and glass fiber layer in sequence. During the laying process, lay fiber mesh layer between carbon fiber layer and glass fiber layer to obtain layered structure. S2. Impregnate the layered structure with resin material and cure it to obtain a carbon-glass hybrid composite material with interlayer toughening; The carbon fiber layer includes continuously laid carbon fiber fabric, and the glass fiber layer includes continuously laid glass fiber fabric.

[0018] Optionally, the carbon fiber layer includes one or more of a woven fabric containing carbon fibers, a unidirectional fabric, and a prepreg.

[0019] Optionally, the fiberglass layer may include one or more of a woven fabric containing glass fibers, a unidirectional fabric, and a prepreg.

[0020] Optionally, the chopped fibers in the fiber web layer include one or more of glass fibers, aramid fibers, basalt fibers, and polyethylene fibers; their common feature is "a porous flexible thin layer composed of randomly distributed chopped fibers".

[0021] Optionally, the modulus of the carbon fiber layer is 60~100Gpa, and the modulus of the glass fiber layer is 15~30Gpa; the modulus of the fiber mesh layer is between that of the carbon fiber layer and the mesh layer, preferably 20~40Gpa; the large difference in modulus between the carbon fiber layer and the glass fiber layer can lead to brittleness, delamination and other problems under stress, resulting in failure; after curing, the mesh layer forms a resin-rich composite material layer with randomly distributed fibers, and its effective modulus is between that of the carbon fiber layer and the glass fiber layer, thereby smoothing the stress change at the interface and significantly reducing the peak shear stress of the composite material after overall molding.

[0022] Optionally, the length of the chopped fibers is 10~50mm; the randomly distributed chopped fibers will be partially embedded in the gaps between the upper and lower layers of fabric to form a three-dimensional mechanical interlock. When the crack expands, these fibers will change the failure mode of the interface from brittle fracture to ductile tearing through the "fiber bridging" effect.

[0023] Optionally, the chopped fibers undergo surface modification treatment, including: silane coupling agent surface modification, plasma grafting, or ultraviolet light grafting.

[0024] Optionally, the fiber mesh layer is laid at a density of 5~120 g / m². 2 Excessively high areal density fiber mesh interlayer may cause interlayer strength discontinuity in carbon-glass composite structures, affecting interface performance.

[0025] Optionally, in S2, the method for impregnating and curing the resin material includes: autoclave process, RTM process, or VARI process.

[0026] Optionally, in S2, the resin material is a thermosetting resin or a thermoplastic resin.

[0027] One or more embodiments of the present invention provide a method for preparing the above-mentioned interlayer toughened carbon-glass hybrid composite material.

[0028] Example 1 A carbon-glass hybrid composite material with interlayer toughening, wherein the raw materials for preparing the carbon fiber layer include 200 g / m 2 Specification T300-3K plain weave dry fabric (modulus 60 GPa), the raw materials for preparing the glass fiber layer include 400 g / m 2 Plain weave dry fabric (modulus 20 GPa), the raw materials for preparing the fiber web layer include 50 g / m 2 Specifications: carbon fiber mesh (modulus 30 GPa), the carbon fiber length in the carbon fiber mesh is 35 ± 5 mm and no surface modification treatment is performed.

[0029] Since the moduli of the carbon fiber layer and the glass fiber layer are 60 GPa and 20 GPa respectively, there is a significant difference in modulus between the two. Under stress, the stress is more likely to concentrate at the macroscopic interface of the heterogeneous materials, leading to brittle and catastrophic delamination.

[0030] Its preparation method includes the following steps: S1. Lay out the fibers in the following sequence: carbon fiber plain weave dry fabric 0° / carbon fiber plain weave dry fabric 45° / carbon fiber plain weave dry fabric 0° / carbon fiber plain weave dry fabric 45° / carbon fiber plain weave dry fabric 0° / carbon fiber mesh / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0°. The resulting layer structure is as follows: Figure 1As shown, it includes an upper carbon fiber layer 1 and a lower glass fiber layer 3. The carbon fiber layer 1 is composed of 5 layers of carbon fiber plain weave dry cloth, and the glass fiber layer 3 is composed of 6 layers of glass fiber dry cloth. A fiber mesh layer 2 is sandwiched between the carbon fiber layer 1 and the glass fiber layer 3.

[0031] S2. Using the VARI molding process, thermosetting epoxy resin material is impregnated in the layered structure and cured. After demolding, a carbon-glass hybrid composite material with interlayer toughening is obtained. In the VARI molding process, the vacuum degree is ≤-0.094Mpa, and the curing temperature rise process includes: 45℃ for 0.5h, 65℃ for 1h, and 80℃ for 3h.

[0032] The overall thickness of the prepared interlayer toughened carbon-glass hybrid composite material is 2.5 mm.

[0033] Comparative Example 1 A carbon-glass hybrid composite material, wherein the raw materials for preparing the carbon fiber layer include 200 g / m 2 Specification T300-3K plain weave dry fabric, the raw materials for preparing the fiberglass layer include 400g / m 2 Plain weave dry cloth.

[0034] Its preparation method includes the following steps: S1. The fiber mesh layer is laid out in the following sequence: carbon fiber plain weave dry cloth 0° / carbon fiber plain weave dry cloth 45° / carbon fiber plain weave dry cloth 0° / carbon fiber plain weave dry cloth 45° / carbon fiber plain weave dry cloth 0° / glass fiber plain weave dry cloth 0° / glass fiber plain weave dry cloth 0° / glass fiber plain weave dry cloth 0° / glass fiber plain weave dry cloth 0° / glass fiber plain weave dry cloth 0° / glass fiber plain weave dry cloth 0° / glass fiber plain weave dry cloth 0°. The difference from Example 1 is that no fiber mesh layer is set.

[0035] S2. Using the VARI molding process, thermosetting epoxy resin material is impregnated in the layered structure and cured. After demolding, carbon-glass hybrid composite material is obtained. In the VARI molding process, the vacuum degree is ≤-0.094Mpa, and the curing temperature rise process includes: 45℃ for 0.5h, 65℃ for 1h, and 80℃ for 3h.

[0036] To facilitate testing, carbon fiber and glass fiber layers of a set thickness were prepared in both Example 1 and Comparative Example 1. In Example 1, a mesh layer was added to accurately measure the performance improvement effect of a single mesh layer.

[0037] Test case According to the standard ASTM D2344 "Standard Test Method for Short-Beam Strength of Polymer Matrix Composite Materials and Their Laminates", the interfacial bonding strength of the carbon-glass hybrid composite materials obtained in Example 1 and Comparative Example 1 were tested, and the results are shown in Table 1.

[0038] Table 1

[0039] It can be seen that, compared with Comparative Example 1, the shear strength of the short beam in Example 1 increased by 13.82%, and the ultimate load displacement increased by 13.51%, indicating that the interface strength and material toughness of Example 1 were significantly improved.

[0040] The morphology of the sample after testing is as follows Figure 2 As shown, Figure 2 (a) shows the surface damage morphology of the sample from Example 1 after a short beam shear test, with the surface layer being a fiberglass layer. Figure 2 (b) shows the surface damage morphology of the sample of Comparative Example 1 after short beam shear test, and the surface layer is a glass fiber layer. It can be seen that the whitening phenomenon of the sample indicates that there are damages such as interface debonding and matrix cracking inside the material. The white area of ​​Comparative Example 1 is significantly larger than that of Example 1, indicating that the delamination damage area of ​​Comparative Example 1 is larger. The principle is that carbon fiber has a very high modulus and glass fiber has a low modulus. When stress is transmitted between layers, due to the difference in modulus, a huge shear stress will be generated at the interface between the two materials. When the interlaminar shear stress exceeds the ultimate strength of the resin, cracks will quickly initiate at the weakest point of the interface, resulting in severe stress concentration. The cracks will rapidly propagate along the interlaminar or low modulus materials, thus resulting in sudden and severe delamination, which is a typical brittle fracture mode. The reduced damage area of ​​the sample in Example 1 is attributed to the addition of a fiber mesh, which creates a modulus transition zone between the carbon fiber and glass fiber layers, smoothing the stress gradient and effectively reducing the peak shear stress at the interface. From a microscopic perspective, the randomly distributed short fibers interpenetrate between the carbon fiber and glass fiber layers, forming a bridging and interlocking mechanism. This provides additional energy dissipation pathways for initial crack propagation. Crack propagation requires additional processes such as fiber pull-out and path deflection, thus reducing the unstable propagation phenomenon. Macroscopically, this manifests as improved interfacial properties, increased material toughness, and enhanced damage tolerance and reliability. These experimental results demonstrate that the method for improving the interfacial properties of carbon-glass composite structures described in this invention is highly effective and provides important reference for engineering applications and safety design in the field of fiber-reinforced composite materials.

[0041] Existing technologies include methods such as stitching, Z-pinning, and tufting to improve the interlayer interface performance. However, these processes can damage the continuous fibers inside the interlayer. This embodiment does not use such methods. Instead, it adopts a purely physical addition process, which promotes the bonding of the fiber web base layer and the glass fiber / carbon fiber layer through resin impregnation and overall co-curing. This does not damage the continuity of the fibers, thereby achieving a low-cost and non-damaging improvement effect on the interlayer interface performance.

[0042] Example 2 A carbon-glass hybrid composite material with interlayer toughening, wherein the raw materials for preparing the carbon fiber layer include 200 g / m 2 Specification T300-3K plain weave dry fabric, the raw materials for preparing the fiberglass layer include 400g / m 2 Plain weave dry fabric, the raw materials for preparing the fiber web layer include 50g / m 2 The carbon fiber mesh is of specification (modulus of 30 GPa) and the carbon fiber mesh undergoes surface modification treatment with silane coupling agent.

[0043] Its preparation method includes the following steps: S1. Lay out the fibers in the following sequence: carbon fiber plain weave dry fabric 0° / carbon fiber plain weave dry fabric 0° / carbon fiber plain weave dry fabric 0° / carbon fiber mesh / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0° / glass fiber plain weave dry fabric 0° / carbon fiber mesh / carbon fiber plain weave dry fabric 0° / carbon fiber plain weave dry fabric 0°. The resulting layup structure is as follows: Figure 3 As shown, there are two carbon fiber layers 1, including a top surface and a bottom surface, with a glass fiber layer 3 sandwiched between the two carbon fiber layers 1, and a fiber mesh layer 2 is respectively provided at the two interlayer interfaces between the glass fiber layer 3 of the two carbon fiber layers 1.

[0044] S2. Using the VARI molding process, thermosetting epoxy resin material is impregnated in the layered structure and cured. After demolding, a carbon-glass hybrid composite material with interlayer toughening is obtained. In the VARI molding process, the vacuum degree is ≤-0.094Mpa, and the curing temperature rise process includes: 45℃ for 0.5h, 65℃ for 1h, and 80℃ for 3h.

[0045] It should be noted that the above-mentioned optional solutions are extended applications that can be deduced by those skilled in the art without creative effort based on the core technical principles disclosed and verified by this invention. These solutions, due to their clear design purpose and similar technical principles, are expected to achieve the beneficial effects described in this invention. The scope of protection of this invention should be determined by the claims and includes all reasonable variations and equivalent substitutions that can be conceived by those skilled in the art based on the concepts disclosed in this specification.

Claims

1. A method for producing an interlayer toughened carbon- glass hybrid composite material, characterized by, The method comprises the steps of: S1, sequentially laying carbon fiber layers and glass fiber layers, and laying a fiber web layer composed of chopped fibers between the carbon fiber layers and the glass fiber layers during the laying process to obtain a layup structure; S2, impregnating the layup structure with a resin material and curing to obtain an interlayer toughened carbon-glass hybrid composite material; The carbon fiber layer comprises a continuous layup of carbon fiber fabric, and the glass fiber layer comprises a continuous layup of glass fiber fabric.

2. The method of making an interlayer toughened carbon- glass hybrid composite of claim 1, wherein, The carbon fiber layer comprises one or more of woven fabric, unidirectional fabric, and prepreg containing carbon fibers.

3. The method of making an interlayer toughened carbon- glass hybrid composite of claim 1, wherein, The glass fiber layer comprises one or more of woven fabric, unidirectional fabric, and prepreg containing glass fibers.

4. The method of making an interlayer toughened carbon- glass hybrid composite of claim 1, wherein, The chopped fibers in the fiber web layer comprise one or more of glass fibers, aramid fibers, basalt fibers, and polyethylene fibers.

5. The method of making an interlayer toughened carbon- glass hybrid composite of claim 4, wherein, The length of the chopped fibers is 10mm-50mm. Alternatively, the chopped fibers are subjected to surface modification treatment, including silane coupling agent surface modification, plasma grafting, or ultraviolet light grafting.

6. The method of making an interlayer toughened carbon- glass hybrid composite of claim 1, wherein, The modulus of the carbon fiber layer is 60-100Gpa, the modulus of the glass fiber layer is 15-30Gpa, and the modulus of the fiber web layer is between the carbon fiber layer and the web layer, preferably 20-40Gpa.

7. The method of making an interlayer toughened carbon- glass hybrid composite of claim 1, wherein, The laid density of the fiber web ply is 5-120 g / m 2 .

8. The method of making an interlayer toughened carbon- glass hybrid composite of claim 1, wherein, In S2, the method of impregnating the resin material and curing comprises a hot press tank process, an RTM process, or a VARI process.

9. The method of making an interlayer toughened carbon- glass hybrid composite of claim 1, wherein, In S2, the resin material is a thermosetting resin or a thermoplastic resin.

10. A method for preparing an interlayer toughened carbon-glass hybrid composite material as claimed in any one of claims 1-9, wherein the interlayer toughened carbon-glass hybrid composite material is prepared by the method.

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