Cross-layer matrix bridging strengthening method for heterogeneous interface of fiber metal laminate and application of cross-layer matrix bridging strengthening method

Abstract

The invention discloses a cross-layer matrix bridging strengthening method for a heterogeneous interface of a fiber metal laminate and application. The cross-layer matrix bridging strengthening method aims at solving the problem that the bonding strength of the heterogeneous interface between layers of the fiber metal laminate is low. A large number of micro-diameter through hole structures are machined in a metal layer of the fiber metal laminate; the resin in the composite material prepreg layer adjacent to the metal layer flows through the micropores of the metal layer and then is subjected to a cross-linking reaction with the resin in the composite material prepreg layer on the other side by utilizing the fluidity of the resin in the composite material prepreg under the heating and pressurizing conditions, so that dense micro-diameter needle-shaped resin columns are formed; the small-diameter needle-shaped resin columns serve as embedded convex bodies and adhesives, the metal micropores serve as embedded concave bodies, and the embedded convex bodies and the metal micropores form an embedded interlayer interface similar to a'resin bridge 'in shape. After curing, the small-diameter needle-shaped resin columns connect the composite material layers on the two adjacent sides of the metal layer together in a cross-layer mode, and the effect of improving the heterogeneous interface bonding strength of the fiber metal laminate based on the cross-layer matrix bridging effect is achieved.

Description

Technical Field

[0001] This invention relates to the field of composite material mechanics and structural design technology, and more particularly to a method and application of cross-layer matrix bridging reinforcement for heterogeneous interfaces of fiber-metal laminates. Background Technology

[0002] Fiber-metal laminate composites are hybrid composites formed by alternating layers of thin metal sheets and fiber prepregs. During the preparation of the fiber-metal laminates, the temperature is insufficient to melt the metal layers. Therefore, the fiber-metal heterogeneous interface is mainly connected by the adhesive effect of the matrix material in the composite material. The composite material layer and the metal layer are typical heterogeneous interfaces. The bonding strength of the heterogeneous interface mainly depends on the shear strength of the matrix. Therefore, the heterogeneous interface becomes the weak link in the overall mechanical properties of the fiber-metal laminate.

[0003] Factors influencing the mechanical properties of fiber-metal heterojunction interfaces include metal layer thickness, metal ductility, composite layup, adhesive materials, and interface pretreatment methods. Adding additional media to the fiber-metal heterojunction interface can help achieve higher transverse elastic modulus and transverse shear strength. For example, using interfacial nanofillers (additives to improve adhesion) or interfacial hybrid bonding methods (e.g., low-temperature brazing of the metal layer and gold-plated fiber layer) can slightly improve the interfacial mechanical properties, but adding new materials inevitably introduces more uncertainties. Metal surface strengthening treatment is an effective way to improve the bonding strength of heterojunction interfaces. For example, metal surface texturing (metal burrs embedded in resin to form a mechanical anchoring effect), metal surface microtexturing (etching microstructures on the metal surface), and metal surface grooving (fibers and resin embedded in grooves on the metal surface to form a mechanical interlocking effect) can all significantly improve the interfacial bonding strength. How to improve the heterojunction bonding strength of fiber-metal laminates by utilizing the original material properties without introducing new interfaces is a technical challenge that requires further research. Summary of the Invention

[0004] To address the problem of low interfacial bonding strength in fiber-metal laminates, which hinders the realization of their macroscopic mechanical properties, this invention proposes a method and application for cross-layer matrix bridging reinforcement of heterogeneous interfaces in fiber-metal laminates. Utilizing the densely packed microporous structure of the metal layers and the flow-filling characteristics of the matrix material in the composite material under hot-pressing conditions, a "resin bridge"-like interfacial interface is introduced into the composite / metal / composite laminate structure, achieving cross-layer matrix bridging reinforcement of the fiber-metal laminate. This method provides a technical approach for strengthening the interface of fiber-metal laminates and offers a technical reference for enhancing the performance of interfacial structures in heterogeneous composite materials.

[0005] The technical means employed in this invention are as follows: A method for cross-layer matrix bridging reinforcement of heterogeneous interfaces in fiber-metal laminates includes the following steps: The metal layer embedded in the fiber metal laminates is processed to form a dense micro-hole structure; The fiber reinforced resin-based composite material prepreg layers and the metal layer are laid up in a predetermined order to form a composite material prepreg / metal / composite material prepreg laminated structure, and the metal layer forms a heterogeneous interface with the composite material prepreg layers on both sides; The laminated structure is subjected to heating and pressure treatment, and the matrix material in the composite material prepreg layer on one side of the metal layer flows through the micro-holes of the metal layer, and the matrix material in the composite material prepreg layer on the other side of the metal layer undergoes crosslinking reaction and bonding; After the composite material prepreg is cured, the matrix material column is filled in all the micro-holes of the metal layer, and the matrix material column and the metal micro-hole form a "resin bridge" embedded interlayer interface, which improves the bonding strength of the fiber metal heterogeneous interface through the cross-layer matrix bridging effect.

[0006] Further, the fiber metal laminates are made of fiber reinforced resin-based composite material prepreg layers and a metal layer embedded in the middle, the composite material prepreg layer refers to a carbon fiber reinforced resin-based composite material prepreg layer, the reinforcing phase is carbon fiber, and the matrix phase is resin. The nominal thickness of a single layer of the composite material prepreg is in the range of 0.125-0.2 mm.

[0007] Further, the metal layer refers to a titanium alloy thin layer to ensure that the metal and carbon fiber do not undergo galvanic corrosion, and the thickness of a single layer of the metal layer is in the range of 0.2-0.5 mm.

[0008] Further, the dense micro-hole structure of the metal layer refers to a large number of regularly arranged micro-sized through holes formed on the titanium alloy thin layer by laser drilling process, wherein the micro-hole diameter is in the range of 1.0-1.5 mm, and the hole area ratio of the metal layer is 10%-20%.

[0009] Further, the matrix material column refers to the resin in the carbon fiber reinforced resin-based composite material prepreg adjacent to the metal layer flowing through the micro-holes of the metal layer under the action of heat and pressure load, and the resin in the carbon fiber reinforced resin-based composite material prepreg on the other side undergoes crosslinking reaction, and a micro-diameter needle-shaped resin column is formed after curing.

[0010] Further, the "resin bridge" embedded interlayer interface refers to a micro-diameter needle-shaped resin column as an embedded convex body and an adhesive, and a metal micro-hole as an embedded concave body, both of which form a "glue rivet hybrid connection" interlayer interface of the composite material / metal / composite material cross-layer structure through embedding.

[0011] Further, the cross-layer matrix bridging refers to that the micro-diameter needle-shaped resin column embedded in the metal micropore connects the carbon fiber reinforced resin matrix composite prepreg layers on both sides of the metal layer together through cross-linking reaction in the form of "resin bridge", thereby improving the effect of heterogeneous interface bonding strength.

[0012] The application further discloses a cross-layer resin bridge chimeric heterogeneous interface reinforced fiber metal laminated plate prepared based on the method, the fiber metal laminated plate comprising an embedded metal layer and fiber reinforced composite prepreg layers on both sides, the metal layer having a dense micropore structure, the micropore being filled with a micro-diameter needle-shaped resin column, the resin column and the metal micropore constituting a "resin bridge" chimeric interlayer interface, the resin column connecting the composite prepreg layers on both sides together, and realizing heterogeneous interface reinforcement.

[0013] Compared with the prior art, the application has the following advantages: 1. The application provides a channel for resin flow and cross-layer connection through the design of the titanium alloy thin layer opening, realizes cross-layer homogenous interface bonding of the composite material layers on both sides of the metal layer, improves the interface bonding strength of the composite material / metal / composite material laminated structure, and avoids the uncertainty of new interfaces without adding additional media.

[0014] 2. The application utilizes the flow and interstitial filling characteristics, cross-linking reaction and bonding characteristics of the matrix material under the heating and high pressure conditions in the forming process of the fiber metal laminated plate, so that the matrix material flowing through the metal micropore forms a micro-diameter needle-shaped matrix material column, and the resin column convex body and the metal micropore concave body constitute a "resin bridge" chimeric interlayer interface.

[0015] 3. The application utilizes the "resin bridge" chimeric interlayer interface to bridge the composite material layers on both sides of the metal layer, realizes the cross-layer matrix bridging reinforcement effect of the composite material / metal / composite material laminated structure, and improves the fiber heterogeneous interface bonding strength. DETAILED DESCRIPTION

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor.

[0017] Figure 1 is a metal layer dense micropore structure illustration; Figure 2 is a fiber metal laminated plate "resin bridge" chimeric interlayer interface formation process schematic diagram; Figure 3Fiber metal heterogeneous interface trans-layer matrix bridging strengthening structure diagram. DETAILED DESCRIPTION

[0018] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0019] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] It should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of the features, steps, operations, devices, components and / or combinations thereof.

[0021] Unless specifically stated otherwise, the relative arrangement of components and steps, numerical expressions, and numerical values set forth in the various embodiments described herein are not limiting. It should be understood that for ease of description and understanding, the dimensions of the various portions shown in the drawings are not drawn to scale. Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the description. In all examples shown and discussed herein, any specific value should be interpreted as merely an example, and not as a limitation. Thus, other examples of the exemplary embodiments can have different values. It should be noted that similar reference numerals and letters in the following drawings represent similar items, and therefore, once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0022] In the description of the application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or positional relationship are generally based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the application and simplifying the description, without the opposite description, these orientation words do not indicate and imply that the device or element indicated must have a specific orientation or be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation on the scope of protection of the application: the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0023] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper" and the like can be used herein to describe the spatial positional relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0024] In addition, it should be noted that the use of "first", "second" and the like to define parts is only for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, therefore it cannot be understood as a limitation on the scope of protection of the application.

[0025] A method for strengthening the interlayer matrix of the heterogeneous interface of a fiber metal laminate, comprising the following steps: Processing the metal layer embedded in the fiber metal laminate to form a dense micro-porous structure; Laying the fiber reinforced resin matrix composite prepreg layer and the metal layer in a predetermined order to form a composite prepreg / metal / composite prepreg laminated structure, and the metal layer forms a heterogeneous interface with the composite prepreg layers on both sides; Heating and pressing the laminated structure to make the matrix material in the composite prepreg layer on one side of the metal layer flow through the micro-porous structure of the metal layer, and cross-linking reaction and bonding with the matrix material in the composite prepreg layer on the other side of the metal layer; After the prepreg of the composite material is cured, the matrix material column is filled in all the micropores of the metal layer to form a "resin bridge" embedded interlayer interface, and the matrix material column and the metal micropore constitute a "resin bridge" embedded interlayer interface, and the cross-layer matrix bridging effect improves the fiber metal heterogeneous interface bonding strength.

[0026] Further, the fiber metal laminate is made of fiber reinforced resin matrix composite material prepreg layers and embedded metal layers, the composite material prepreg layer refers to a carbon fiber reinforced resin matrix composite material prepreg layer, the reinforcing phase is carbon fiber, the matrix phase is resin, and the nominal thickness of a single layer of the composite material prepreg is in the range of 0.125-0.2mm.

[0027] Further, the metal layer refers to a titanium alloy thin layer to ensure that the metal and the carbon fiber do not undergo galvanic corrosion, and the thickness of a single layer of the metal layer is in the range of 0.2-0.5mm.

[0028] Further, the metal layer densely filled with microporous structure refers to a large number of microporous holes with regular arrangement formed on the titanium alloy thin layer by laser drilling process, wherein the micropore diameter is in the range of 1.0-1.5mm, and the metal layer has a hole area ratio of 10%-20%.

[0029] Further, the matrix material column refers to the resin in the carbon fiber reinforced resin matrix composite material prepreg adjacent to the metal layer flowing through the metal layer micropore under the action of heat and pressure load, and cross-linking with the resin in the other side carbon fiber reinforced resin matrix composite material prepreg, and the microporous resin column with a small diameter is formed after curing.

[0030] Further, the "resin bridge" embedded interlayer interface refers to that the microporous resin column with a small diameter acts as an embedded convex body and an adhesive, the metal micropore acts as an embedded concave body, and the two form a "glue rivet mixed connection" interlayer interface of the composite material / metal / composite material cross-layer structure through embedding.

[0031] Further, the cross-layer matrix bridging effect refers to that the microporous resin column with a small diameter embedded in the metal micropore connects the carbon fiber reinforced resin matrix composite material prepreg layers on both sides of the metal layer together through cross-linking reaction in the form of "resin bridge", thereby improving the effect of heterogeneous interface bonding strength.

[0032] The application also discloses a cross-layer resin bridge embedded heterogeneous interface reinforced fiber metal laminate prepared based on the above method, the fiber metal laminate comprises an embedded metal layer and fiber reinforced composite material prepreg layers on both sides, the metal layer has a densely microporous structure, the microporous resin column with a small diameter is filled in the micropore, the resin column and the metal micropore constitute a "resin bridge" embedded interlayer interface, the resin column connects the composite material prepreg layers on both sides through cross-linking reaction, and the heterogeneous interface is reinforced.

[0033] The fiber-reinforced resin-based composite prepreg involved in this invention can be made of materials including continuous fiber carbon fiber reinforced resin-based unidirectional prepreg or continuous fiber glass fiber reinforced resin-based unidirectional prepreg. Examples of continuous fiber carbon fiber reinforced resin-based unidirectional prepregs include T300 / 7901, T800 / X850, and IMS194 / 977-2, while examples of continuous fiber glass fiber reinforced resin-based unidirectional prepregs include J2400 / EM107 and J7781 / EM105. The regular distribution of the densely packed microporous structure involved in this invention can be categorized into rectangular array forms, fractal forms, etc.

[0034] Example 1 This invention discloses a method for cross-layer matrix bridging reinforcement of heterogeneous interfaces in fiber-metal laminates. The cross-layer matrix bridging reinforcement described in this invention mainly involves creating a densely distributed microporous structure in the metal layer of the fiber-metal laminate. Utilizing the flow-filling characteristics of the matrix material in the composite prepreg and the principle of homogeneous matrix cross-linking reaction during the hot-pressing process, the matrix material flows through the microporous structure of the metal layer to form a cross-layer matrix bridging structure. A fiber-metal laminate composed of T300 / 7901 carbon fiber reinforced epoxy resin-based woven composite prepreg and TC4 titanium alloy thin layers is used as an example to illustrate the specific implementation of this invention. The specific steps include: 1) In this embodiment, the geometric dimensions of the fiber metal laminate are 130mm long × 13mm wide × 2.2mm high, and it adopts [(0 / 90)2 / Ti / (90 / 0)2]. S Symmetrical layup, with the length direction of the fiber-metal laminate selected as the 0° reference direction, where the numbers represent the layup angle of each layer of the T300 / 7901 carbon fiber reinforced epoxy resin matrix composite material, the nominal thickness of a single [0 / 90] braided layer is 0.2 mm, Ti represents the location of the TC4 titanium alloy thin layer, and the thickness of a single metal layer is 0.3 mm; 2) Referring to the geometric dimensions of the titanium alloy thin layer (130mm long × 13mm wide × 0.3mm high), 80 micro-sized through holes (16 long × 5 wide) with a diameter of 1.0mm were manufactured in an array on the two titanium alloy thin layers using a continuous laser processing technology. The hole area in each titanium alloy thin layer is approximately 251.2mm². 2 (Approximately 15% of the area of ​​the thin metal layer), such as Figure 1 As shown in the figure, 4 represents the TC4 titanium alloy layer, and 5 represents a through hole with a diameter of 1.0 mm; 3) The T300 / 7901 woven prepreg layers and TC4 titanium alloy layers are placed in the mold according to the designed layering sequence, and then placed in a hot press for hot pressing, the pressure is set to 0.6 MPa, and the temperature is raised to 130℃ at a rate of 2℃ / min and kept for 120 min. During this process, the 7901 epoxy resin of the upper layer of the woven prepreg layer adjacent to the titanium alloy layer flows through the micropores of the TC4 titanium alloy thin layer under the action of hot pressing, and the 7901 epoxy resin of the lower layer of the woven prepreg layer is crosslinked under the action of hot pressing to form a "resin bridge" embedded interlaminar interface, as shown in Figure 2 Figure 1 represents the 0° direction fiber in the T300 / 7901 woven prepreg layer, 2 represents the 90° direction fiber in the T300 / 7901 woven prepreg layer, 3 represents the 7901 epoxy resin in the T300 / 7901 woven prepreg layer, and 6 represents the "resin bridge" embedded interlaminar interface. 4) The temperature is lowered to below 60℃ at a rate of 2℃ / min, and then demolded. The "resin bridge" embedded interface "anchors" the titanium alloy thin layer and the upper and lower layers of T300 / 7901 carbon fiber reinforced resin matrix composite material layers together in a cross-layer matrix bridging form, as shown in Figure 3 Figure 2, to obtain a fiber-metal laminated plate product with heterogeneous interface strengthening.

[0035] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of strengthening interfacial translayer matrix bridging in a fiber metal laminate, characterized by, The method comprises the following steps: Processing the metal layer embedded in the fiber metal laminates to form a dense micro-hole structure; Laying the fiber reinforced resin-based composite material prepreg layers and the metal layer in a predetermined order to form a composite material prepreg / metal / composite material prepreg laminated structure, and the metal layer and the composite material prepreg layers on both sides form heterogeneous interfaces respectively; Performing heating and pressurizing treatment on the laminated structure, so that the matrix material in the composite material prepreg layer on one side of the metal layer flows through the micro-holes of the metal layer, and cross-linking reaction and bonding occur between the matrix material in the composite material prepreg layer on the other side of the metal layer; After the composite material prepreg is cured, the matrix material columns are filled in all the micro-holes of the metal layer, and the matrix material columns and the metal micro-holes form a "resin bridge" embedded interlayer interface, and the cross-layer matrix bridging effect improves the bonding strength of the fiber metal heterogeneous interface.

2. The method of claim 1, wherein, The fiber metal laminates are made of fiber reinforced resin-based composite material prepreg layers and a metal layer embedded in the middle, the carbon fiber reinforced resin-based composite material prepreg layer has a carbon fiber reinforcing phase and a resin matrix phase, and the nominal thickness of a single layer of the composite material prepreg is in the range of 0.125-0.2 mm.

3. The method of claim 1, wherein, The metal layer refers to a titanium alloy thin layer to prevent galvanic corrosion between the metal and the carbon fiber, and the thickness of a single layer of the metal layer is in the range of 0.2-0.5 mm.

4. The method of claim 1, wherein, The dense micro-hole structure of the metal layer refers to a large number of regularly arranged micro-holes with small sizes formed on the titanium alloy thin layer by a laser drilling process, wherein the diameter of the micro-holes is in the range of 1.0-1.5 mm, and the area ratio of the micro-holes in the metal layer is 10%-20%.

5. The method of claim 1, wherein, The matrix material column refers to a small-diameter needle-shaped resin column formed by the resin in the carbon fiber reinforced resin-based composite material prepreg adjacent to the metal layer flowing through the micro-holes of the metal layer under the action of heat and pressure, and cross-linking reaction occurring between the resin in the carbon fiber reinforced resin-based composite material prepreg on the other side, and the small-diameter needle-shaped resin column being formed after curing.

6. The method of claim 1, wherein, The "resin bridge" embedded interlayer interface refers to the small-diameter needle-shaped resin column as an embedded convex body and an adhesive, the metal micro-holes as an embedded concave body, and the two forming a "glue rivet hybrid connection" interlayer interface of the cross-layer composite material / metal / composite material structure through embedding.

7. The method of claim 1, wherein, The cross-layer matrix bridging effect refers to the small-diameter needle-shaped resin column embedded in the metal micro-holes connecting the carbon fiber reinforced resin-based composite material prepreg layers on both sides of the metal layer together in the form of a "resin bridge" through cross-linking reaction, and thus improving the bonding strength of the heterogeneous interface.

8. A crossply resin-bridged chimeric heterogeneous interface-stiffened fiber metal laminate characterized by, The fiber metal laminates are prepared by the method of any one of claims 1-7. The fiber metal laminates comprise a metal layer embedded in the middle and fiber reinforced composite material prepreg layers on both sides, the metal layer has a dense micro-hole structure, the micro-holes are filled with small-diameter needle-shaped resin columns, the resin columns and the metal micro-holes form a "resin bridge" embedded interlayer interface, the resin columns cross-link the composite material prepreg layers on both sides, and the heterogeneous interface is reinforced.

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