Lightweight composite reinforcing material

Abstract

The lightweight composite reinforced material is a novel composite material combining a carbon fiber laminated structure and a high-strength alloy inner core, the toughness and the impact resistance of the alloy inner core are improved through a core-shell structure and a dynamic aging process, high strength and lightweight are provided for carbon fiber lamination through magnetic field assisted orientation and nano interface strengthening, and the two parts are combined, so that the strength and the weight of the carbon fiber lamination are improved. The problem of microcracks caused by difference of thermal expansion coefficients is solved through a low-temperature rapid curing and interface treatment technology, and the overall performance is improved through a synergistic effect; according to the material system, through multi-scale structural design and process innovation, the bottleneck of strength-toughness contradiction and interface failure of a traditional composite material is broken through, and the material system has the characteristics of light weight, high bearing capacity and multiple functions and is suitable for high-performance equipment manufacturing under extreme working conditions. The method is used for applications requiring high-strength and light-weight equipment, such as aerospace, energy traffic and the like.

Description

Technical Field

[0001] A lightweight composite reinforcement material is a new type of composite material that combines a carbon fiber laminated structure with a high-strength alloy core. This material system breaks through the strength-toughness contradiction and interface failure bottleneck of traditional composite materials through multi-scale structural design and process innovation. It has the characteristics of lightweight, high load-bearing capacity and multi-function, and is suitable for high-performance equipment manufacturing under extreme working conditions. Background Art

[0002] Existing technology defects: a) Strength-toughness imbalance: When the yield strength of traditional 7xxx series aluminum alloy is >500MPa, the elongation is <8% (GB / T228.1 standard); b) Significant anisotropy: the transverse tensile strength of the extruded material is 30-40% lower than that of the longitudinal tensile strength; c) Composite interface failure: Micro cracks are caused by the difference in thermal expansion coefficient when composited with carbon fiber. The carbon fiber layers are only mechanically anchored by resin, and the shear strength is usually <50MPa (ASTM D2344 standard); d) Anisotropy contradiction: 0° / 90° orthogonal ply leads to >100 times difference in in-plane thermal conductivity (X / Y direction vs Z direction); e) Process defects: porosity of hand-laid layers > 2%, energy consumption of autoclave molding accounts for more than 60% of production costs. Summary of the invention

[0003] A new type of lightweight composite reinforcement material combines a carbon fiber laminate structure with a high-strength alloy core. The composition and structural design of the composite material (alloy core + carbon fiber laminate + interface transition layer), core-shell structure and dynamic aging process make the alloy core more tough and impact-resistant. Magnetic field-assisted orientation and nano-scale interface strengthening provide high strength and lightweight for the carbon fiber laminate. The micro-crack problem caused by the difference in thermal expansion coefficient is solved through low-temperature rapid curing and interface treatment technology.

[0004] High-strength alloy inner core, outer layer covered with carbon fiber / epoxy resin prepreg (laying angle ±45°), there is a mechanical-chemical composite interface between the inner core and the outer layer, including a laser texturing area with a depth of 50~200μm, and the carbon fiber prepreg is infiltrated by in-situ curing resin to form a three-dimensional interlocking.

[0005] The high-strength alloy core-shell structure is designed to adapt to thermal expansion, and the surface is coated with a nanocrystalline gradient layer (grain size 50-200nm) to suppress microcracks caused by the temperature difference between the alloy and the carbon fiber.

[0006] Cross-scale interface regulation: Preparation of micron-scale dovetail grooves + nanoscale oxidation anchor points on the alloy surface by laser cladding; nanoscale interface strengthening, functionalized graphene (plasma grafting + electrochemical deposition double-step treatment), interlayer insertion of electrospun PVDF nanofiber membranes (diameter 200-500nm, porosity >85%) to form a covalent bond bridging network (chemical bond density increased by 3 times).

[0007] Dynamic aging process: electromagnetic pulse assisted aging (frequency 5kHz, magnetic field intensity 0.8T), three-dimensional interpenetrating structure design, the magnetic field gradient direction is at an angle of 30°~60° with the ply plane, and the magnetic field is used to induce the carbon fibers to be vertically arranged in the Z direction. The uniformity of the precipitated phase distribution is increased by 60%, thereby increasing toughness and impact resistance.

[0008] Low temperature and fast curing: Using UV light intensity (50-80mW / cm²) vacuum ultraviolet curing resin system, the molding temperature is reduced from the traditional 180℃ to 80℃, shortening the curing time.

[0009] Cross-scale collaborative enhancement: a) The nanocrystalline gradient layer (grain size 50~200nm) of the alloy core and the Z-direction orientation design of the carbon fiber stacking synergistically improve the multi-directional load-bearing capacity; b) Graphene / PVDF nanomembrane constructs a "physical anchoring + chemical bonding" dual-mode interface with a shear strength of 95MPa (ASTM D3165).

[0010] Functional integration breakthrough: a) Realize the anisotropic regulation of electrical and thermal conductivity through magnetic field programming (X / Y direction resistivity <10⁻³Ω·cm, Z direction thermal conductivity >15W / m·K); b) Sc / Zr microalloying (atomic ratio 1.2~1.8) of the alloy core inhibits stress corrosion sensitivity (salt spray corrosion rate 3000h <0.015mm / a).

[0011] This material system breaks through the strength-toughness contradiction and interface failure bottleneck of traditional composite materials through multi-scale structural design and process innovation. It has the characteristics of lightweight, high load-bearing and multifunctionality, and is suitable for high-performance equipment manufacturing under extreme working conditions. Specific implementation methods

[0012] Material system: a) Inner core: Made of high-strength and tough aluminum alloy (Al-Zn-Mg-Sc-Zr system), with yield strength ≥635MPa, elongation >12%, and surface laser cladding to form micron-level dovetail grooves and nano-level alumina anchor points; b) Outer layer: carbon fiber / epoxy resin laminate structure (T800 grade), oriented by magnetic field (Z-direction deflection 15°~75°), with amino-functionalized graphene (mass fraction 5~8%) and PVDF nanofiber membrane embedded between the layers.

[0013] Interface Engineering: a) Mechanical-chemical composite bonding: The aluminum alloy surface is laser textured to a depth of 50-200 μm, and the carbon fiber prepreg is infiltrated by in-situ cured resin to form a three-dimensional interlocking; b) Thermal expansion adaptation: The interface layer is coated with a nanocrystalline gradient layer (grain size 50~200nm) to inhibit the expansion of aluminum (23×10⁻ 6 / ℃) and carbon fiber (0.5×10⁻ 6 / ℃) micro cracks caused by temperature difference.

[0014] Process preparation method: A method for preparing a high-strength and tough aluminum alloy (Al-Zn-Mg-Sc-Zr system) inner core material comprises: a) Semi-continuous casting: cooling rate 50~80℃ / s, obtaining equiaxed ingot (average grain size ≤50μm); b) Multi-directional forging: cumulative deformation > 75%, final forging temperature 350±10℃; c) Electromagnetic pulse aging: Apply alternating magnetic field at 120~150℃ for 8~12h.

[0015] Carbon fiber composite material stacking molding method: a) Laying the prepreg on the mold, each layer contains 5-8% by mass of amino-functionalized graphene, and inserting electrospun PVDF nanofiber membrane (diameter 200-500nm, porosity>85%) between the layers; the resin matrix of the prepreg is a bismaleimide / epoxy resin hybrid system, and the glass transition temperature is ≥220℃; b) The magnetic field generator uses a Halbach permanent magnet array, which applies a 0.5-3T gradient magnetic field to deflect the carbon fiber along the Z axis by 15°~75°, and the magnetic field uniformity error is <5%; c) Pulsed ultraviolet light source (wavelength 365nm, power density 50~80mW / cm², 80℃ / 30min, porosity <0.5%) is used for staged curing in a vacuum environment, and the molding temperature is reduced from the traditional 180℃ to 80℃, shortening the curing time.

[0016] Existing example comparison and data support: Example 1: Aerospace wing spar joint (high strength and toughness aluminum alloy Al-Zn-Mg-Sc-Zr system) Alloy composition: Zn7.0%, Mg2.5%, Sc0.20%, Zr0.10% Precipitation phase density: 8.2×10²² / m³ (TEM statistics) Mechanical properties: index Traditional 7075 Example 1 Improvement rate Yield strength (MPa) 503 635 +26% Elongation (%) 7.2 12.8 +78% Fracture toughness KIC 28MPa√m 41MPa√m +46% Example 2: Aerospace cabin structural parts (carbon fiber / epoxy resin laminated structure) Laying method: [(0° / 90°)6]s → improved to [+45° / ~45° / vertical in Z direction]8 Curing conditions: 80℃ UV curing for 30min + post-curing at 120℃ / 2h Performance comparison: index Traditional crafts Example 2 Improvement rate Interlaminar shear strength 48MPa 89MPa +85% Z thermal conductivity 0.8W / mK 12.3W / mK +1437% Porosity 1.8% 0.3% -83% Example 3: New energy vehicle battery tray (traditional aluminum ~ carbon fiber composite structure) Inner core thickness: 2mm, surface laser texturing depth 150μm (dovetail groove width 200μm) Carbon fiber layup: T800 / epoxy resin, 6 layers of quasi-isotropic layup Functional testing: Three-point bending load: conventional structure 18kN → composite structure 32kN (+78%) Interfacial peel strength: 15N / mm → 28N / mm (ASTM D3167) Thermal cycle performance (-40℃↔85℃, 1000 times): No delamination (better than IEC 60068-2-14).

[0017] The performance advantages of the present invention and AI theoretical calculation data: Performance Indicators Traditional aluminum-carbon fiber composite The present invention Improvement rate Specific strength (MPa·cm³ / g) 280 420 +50% Interface peel strength (N / mm) 18 35 +94% Z thermal conductivity (W / m·K) 0.7 15.2 +2071% Impact toughness(kJ / m²) 85 145 +71% Thermal cycle life (-40~120℃) 500 times without failure 1500 times without delamination +200% .

[0018] Sample preparation: a) "Inner core" high-strength and tough aluminum alloy (Al-Zn-Mg-Sc-Zr system) inner core material, including by mass percentage: Zn 6.5~7.2%, Mg 2.1~2.8%, Sc 0.15~0.25%, Zr 0.08~0.12%, Ti≤0.05%, Fe≤0.15%, the balance is Al and unavoidable impurities, among which the Sc / Zr atomic ratio is controlled between 1.2~1.8; b) The “outer layer” carbon fiber (T800 grade) / epoxy resin laminated structure, the resin matrix is ​​a bismaleimide / epoxy resin hybrid system, and each layer contains 5-8% by mass of amino-functionalized graphene.

[0019] Integrated molding process: Step 1: Dynamic aging treatment of aluminum alloy inner core (electromagnetic pulse assisted, 5kHz / 0.8T, precipitate phase uniformity improved by 60%); Step 2: Magnetic field-assisted laying of carbon fiber prepreg (1.5T static magnetic field, Z-direction fiber volume fraction>40%); Step 3: Vacuum UV curing (80°C / 30min, porosity <0.5%).

[0020] Key process parameters: Magnetic field gradient: 0.5~3T / mm (Halbach permanent magnet array); Curing pressure: 0.6~1.2MPa (flexible air bag pressurization).

[0021] Test method: Optimize structural stress distribution through finite element analysis (FEA); Declare material performance certification method in SAE J2340 (automobile collision standard).

[0022] Application scenarios: a) Aerospace: satellite brackets, wing beam joints (weight reduction of 30%+, meeting MIL-STD-810G vibration standards); b) New energy vehicles: battery box, chassis structure (electromagnetic shielding effectiveness> 70dB, lightning damage area reduced by 60%); c) High-end equipment: lightweight robot arm (dynamic load tolerance increased by 55%, JISB 8432 standard).

[0023] The basic principles, main features and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention shall be defined by the attached claims and their equivalents.

Claims

1. A lightweight composite reinforced material, characterized by: A new type of composite material that combines a carbon fiber laminated structure with a high-strength alloy core. The composition and structural design of the composite material (alloy core + carbon fiber laminated + interface transition layer), core-shell structure and dynamic aging process make the alloy core more tough and impact-resistant. Magnetic field-assisted orientation and nano-scale interface strengthening provide high strength and light weight for the carbon fiber laminated structure. Low-temperature rapid curing and interface treatment technology are used to solve the microcrack problem caused by the difference in thermal expansion coefficient. This material system has broken through the strength-toughness contradiction and interface failure bottleneck of traditional composite materials through multi-scale structural design and process innovation, and has the characteristics of light weight, high load-bearing capacity and multi-function, making it suitable for high-performance equipment manufacturing under extreme working conditions.

2. A lightweight composite reinforced material according to claim 1, characterized in that: A novel composite material comprising a carbon fiber laminate structure and a high-strength alloy inner core, wherein the high-strength alloy inner core is coated with a carbon fiber / epoxy resin prepreg (laying angle ±45°) on the outer layer, and a mechanical-chemical composite interface is provided between the inner core and the outer layer, including a laser texturing area with a depth of 50-200μm, and the carbon fiber prepreg is infiltrated by in-situ cured resin to form a three-dimensional interlocking.

3. The lightweight composite reinforced material according to claim 1, characterized in that: The high-strength alloy core-shell structure is designed to adapt to thermal expansion, and the surface is coated with a nanocrystalline gradient layer (grain size 50-200nm) to suppress microcracks caused by the temperature difference between the alloy and the carbon fiber.

4. The lightweight composite reinforced material according to claim 1, characterized in that: Cross-scale interface regulation, preparation of micron-scale dovetail grooves + nano-scale oxidation anchor points on the alloy surface by laser cladding; nano-scale interface strengthening, functionalized graphene ("plasma grafting + electrochemical deposition" two-step treatment), interlayer insertion of electrospun PVDF nanofiber membranes (diameter 200-500nm, porosity >85%) to form a covalent bond bridging network.

5. The lightweight composite reinforced material according to claim 1, characterized in that: The dynamic aging process uses electromagnetic pulse assisted aging (frequency 5kHz, magnetic field intensity 0.8T), a three-dimensional interpenetrating structure design, and the magnetic field gradient direction is at an angle of 30°-60° with the ply plane. The magnetic field induces the carbon fibers to be vertically arranged in the Z direction, and the uniformity of the precipitated phase distribution is increased by 60%, thereby increasing toughness and impact resistance.

6. The lightweight composite reinforced material according to claim 1, characterized in that: Fast curing, using UV light intensity (50-80mW / cm²) vacuum ultraviolet curing resin system, the molding temperature is reduced from the traditional 180℃ to 80℃, shortening the curing time.

7. The lightweight composite reinforced material according to claim 1, characterized in that: Cross-scale collaborative enhancement: a) The nanocrystalline gradient layer (grain size 50-200nm) of the alloy core and the Z-direction orientation design of the carbon fiber stacking work together to improve the multi-directional load-bearing capacity; b) Graphene / PVDF nanomembrane constructs a "physical anchoring + chemical bonding" dual-mode interface.

8. The lightweight composite reinforcement material according to claim 1 is characterized in that: Integrated Breakthrough: a) Realize the anisotropic regulation of electrical and thermal conductivity through magnetic field programming (X / Y direction resistivity <10⁻³Ω·cm, Z direction thermal conductivity >15W / m·K); b) Sc / Zr microalloying (atomic ratio 1.2-1.8) of the alloy core inhibits stress corrosion sensitivity (salt spray corrosion rate 3000h <0.015mm / a).