Graphitized carbon fiber reinforced magnesium-based composite material with multi-layer interface structure and preparation method of graphitized carbon fiber reinforced magnesium-based composite material
By forming a multi-layer interface structure on the carbon fiber surface, the problem of poor bonding between carbon fiber and magnesium matrix is solved, higher interface bonding strength and stress transfer are achieved, and the mechanical properties and thermal conductivity of magnesium-based composite materials are improved.
Patent Information
- Application Number
- CN202510938707.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2025-10-03
Smart Images
Figure CN120738573A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of magnesium alloys and relates to a graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure and a preparation method thereof. Background Art
[0002] Magnesium is the lightest metal among structural metals, with a density of only 1.74g / cm2, about 2 / 3 of that of aluminum. 3 . Magnesium alloys have the advantages of high specific strength, high specific stiffness, excellent damping coefficient, dimensional stability and electromagnetic shielding capability, and large reserves. In recent years, researchers have extensively explored a variety of methods to introduce reinforcements to construct composite materials in order to improve the comprehensive performance of magnesium alloys. Among them, carbon fiber, as a high-strength, lightweight material, has been considered as one of the ideal reinforcements for magnesium alloys because of its significant reinforcement effect on magnesium alloys. Carbon fiber can significantly improve the comprehensive performance of composite materials by forming a composite structure with the magnesium matrix, especially in terms of enhanced strength and certain physical properties.
[0003] However, in the existing preparation process of carbon fiber reinforced magnesium-based composite materials, the interface bonding is often not ideal due to the low wettability of carbon fiber and magnesium metal. In addition, the use of alloying elements such as AZ and AM alloys to improve interface bonding often leads to the production of hard and brittle interface products, which not only damages the carbon fiber, but also produces great stress concentration, causing the material to fail prematurely. How to ensure the formation of good interface products between carbon fiber and magnesium matrix during the preparation process and form moderate interface bonding to improve its overall performance has become an important challenge in research in this field. Summary of the Invention
[0004] In view of this, one of the objects of the present invention is to provide a graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure; the second object is to provide a preparation method of a graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure.
[0005] In order to achieve the above object, the present invention provides the following technical solutions:
[0006] 1. A graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure, wherein the composite material is a zirconium-containing rare earth magnesium alloy dispersed with graphitized carbon fibers, and the graphitized carbon fibers are sequentially wrapped from the inside to the outside by a rare earth sesquioxide layer, a zirconium carbide layer, and a magnesium rare earth layer.
[0007] Preferably, the composite material contains at least two rare earth elements selected from the group consisting of Y, Nd and Gd.
[0008] Preferably, in terms of mass percentage, the zirconium content in the composite material is not less than 0.5 wt.%, and the total rare earth element content is not less than 4 wt.%.
[0009] Preferably, the zirconium-containing rare earth magnesium alloy is one of Mg-Y-Nd-Gd-Zr alloy, Mg-Gd-Nd-Zn-Zr alloy, Mg-Gd-Nd-Mn-Zr alloy, Mg-Y-Gd-Zr alloy or Mg-Y-Nd-Zr alloy.
[0010] Preferably, the Mg-Y-Nd-Gd-Zr alloy consists of the following components by mass percentage: 3.5-5wt.% Y, 1.5-3wt.% Nd, 0.7-1.3wt.% Gd, 0.5-0.7wt.% Zr, unavoidable impurities ≤0.25wt.%, and the balance Mg.
[0011] Preferably, the graphitized carbon fiber is prepared as follows:
[0012] Heat the carbon fiber cloth to 1100-1500°C under vacuum conditions and keep it warm for 2-6 hours, then continue to heat it to 2700-3300°C and keep it warm for 1-3 hours.
[0013] Preferably, the vacuum condition is as follows: the vacuum degree is not higher than 1×10 -1 Pa.
[0014] 2. The preparation method of the graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure is as follows:
[0015] Add zirconium-containing rare earth magnesium alloy to the graphitized carbon fiber, heat to 700-750° C. under vacuum conditions until the zirconium-containing rare earth magnesium alloy is melted, apply pressure to allow the molten zirconium-containing rare earth magnesium alloy to infiltrate the graphitized carbon fiber, and cool.
[0016] Preferably, the vacuum condition is as follows: the vacuum degree is not higher than 1×10 -1 Pa.
[0017] Preferably, the pressurizing comprises applying a pressure of 6-10 MPa.
[0018] The beneficial effects of the present invention are as follows: the present invention provides a graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure and a preparation method thereof, wherein the graphitized carbon fiber in the composite material is sequentially wrapped by a rare earth sesquioxide layer, a zirconium carbide layer and a magnesium rare earth layer from the inside to the outside to form a multi-layer interface structure (such as Figure 1As shown), this structure can significantly improve the interfacial bonding strength between carbon fiber and magnesium matrix, effectively prevent the occurrence of interface cracking and debonding, optimize the microstructure of the composite material, and thus effectively transfer the load, overcoming the problem of weak or strong stress transmission caused by poor interface bonding in traditional carbon fiber reinforced magnesium-based composite materials, effectively improving the reinforcing effect of carbon fiber in the magnesium matrix, and ultimately improving the tensile strength of the magnesium-based composite material. Among them, the tensile strength of the magnesium-based composite material in the present invention is 500-700MPa, the elastic modulus is 300-400GPa, and the thermal conductivity is 300-400W·m -1 ·K -1 In addition, the process flow of the present invention has a wide operating window and strong controllability, and has significant economic benefits and application prospects.
[0019] In the present invention, Zr and rare earth solute atoms gather at the interface between carbon fiber and magnesium matrix, forming a multilayer interface structure composed of rare earth sesquioxide layer, zirconium carbide layer and magnesium rare earth layer. Among them, due to the high interfacial energy of the fiber / matrix interface, rare earth elements preferentially segregate here, and this segregation initiates two synergistic strengthening mechanisms: one involves chemical reaction, i.e., the formation of nano-scale rare earth sesquioxide layer (Y2O3, Nd2O3, Gd2O3), which presents a relatively uneven distribution and has an irregular diffusion pattern extending from the matrix to the interior of the fiber, so this layer is close to the graphitized carbon fiber; on the other hand, the formation of Mg-RE second phase (Mg2O3) which further enhances the physical and mechanical bite. 24 Y5, MgNd, MgGd), this layer is closer to the magnesium matrix. At the same time, carbon atoms diffuse from the fiber into the metal matrix, unidirectionally diffusing in the solid state within the in-situ generated ZrCx layer. After passing through the ZrCx layer, they react with the Zr element in the matrix, further increasing the thickness of the ZrCx layer, which is located between the rare earth sesquioxide layer and the Mg-RE layer.
[0020] In terms of mechanical properties, the interface reaction layer produced by the addition of Zr and RE elements makes C fThe relationship between ZrCx and Mg changes from relying entirely on mechanical and physical adhesion to relying mainly on chemical bonds. This process significantly improves wettability and promotes stress transfer. In addition, the emergence of the three-layer interface also prevents fiber damage that may occur during the infiltration process. Among them, the rare earth sesquioxide layer and the ZrCx layer exhibit high strength and hardness, and exist continuously on the surface of the carbon fiber. They have excellent bonding with both the matrix and the fiber, which promotes the deflection of the crack when it extends to the interface under a relatively low load, and transforms the original stress concentration and fiber cutting loading behavior into continuing to propagate along the interface layer, that is, continuing to extend along the fiber along the loading direction. This process can be regarded as a stress relaxation process and enables the material to withstand greater external loads. In addition, due to the continuous presence of these two interface layers on the fiber surface, a bridging effect can be generated between the transverse and longitudinal fibers, allowing the crack to transfer between different transverse fibers through the longitudinal fibers, thereby dispersing the local stress concentration in the material. Furthermore, the magnesium rare earth layer can fill any gaps between the fiber and the matrix, increasing the density of the composite and preventing cracks in the gaps. Its unique fragmented and dense morphology also greatly enhances the roughness between the fiber and the matrix. These two phenomena improve the stress transfer between the fiber and the matrix from the perspective of physical bonding. As a result, the graphitized carbon fiber reinforced magnesium matrix composite material can obtain excellent mechanical properties under the synergistic strengthening mechanism of the three interfaces.
[0021] The high modulus of elasticity of the rare earth sesquioxide and zirconium carbide layers also contributes to the composite's elastic modulus, nearly reaching the theoretical value achieved by the law of mixtures. The creation of several interfacial layers also reduces the resistance to phonon and electron transmission between the carbon fiber and magnesium matrix, resulting in the material's excellent thermal conductivity.
[0022] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:
[0024] Figure 1 Schematic diagram of the multilayer interface structure in the graphitized carbon fiber reinforced magnesium-based composite material of the present invention;
[0025] Figure 2This is a SEM-EDS surface scanning result distribution diagram of the graphitized carbon fiber reinforced magnesium-based composite material prepared in Example 1 of the present invention;
[0026] Figure 3 TEM-EDS image of the graphitized carbon fiber reinforced magnesium-based composite material prepared in Example 1 of the present invention;
[0027] Figure 4 TEM-SEAD results of the graphitized carbon fiber reinforced magnesium-based composite material prepared in Example 1 of the present invention;
[0028] Figure 5 This is a graph showing the thermal conductivity test results of the graphitized carbon fiber reinforced magnesium-based composite material prepared in Example 1 of the present invention;
[0029] Figure 6 Graphs showing the mechanical properties test results of the graphitized carbon fiber reinforced magnesium-based composite materials prepared in Examples 1 to 3 of the present invention and the Mg-Y-Nd-Gd-Zr alloy in Example 1. DETAILED DESCRIPTION
[0030] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.
[0031] Example 1
[0032] Preparation of graphitized carbon fiber reinforced magnesium matrix composites
[0033] S1. Ingredients by volume percentage: 35.52 vol.% graphitized carbon fiber, the balance being Mg-Y-Nd-Gd-Zr alloy; the Mg-Y-Nd-Gd-Zr alloy is composed of the following components by mass percentage: 4 wt.% Y, 2 wt.% Nd, 1 wt.% Gd, 0.5 wt.% Zr, unavoidable impurities ≤ 0.25 wt.%, and the balance being Mg;
[0034] S2. Cut the carbon fiber cloth into a size of 150 mm × 100 mm and lay it out in the installed mold. Heat it to 1200 ° C and keep it for 2 hours under a vacuum degree of 0.1 Pa. Then continue to heat it to 2950 ° C and keep it for 1 hour to obtain graphitized carbon fiber. Then add Mg-Y-Nd-Gd-Zr alloy, heat it to 700 ° C until the alloy melts, and apply a pressure of 8 MPa to make the molten alloy infiltrate into the graphitized carbon fiber, and cool it.
[0035] The graphitized carbon fiber reinforced magnesium matrix composite material prepared in Example 1 was characterized by scanning electron microscopy and energy dispersive spectrometer. Figure 2 As shown by Figure 2 It can be seen that there are a large number of fine dispersed second phases at the interface of the composite material, among which rare earth elements are segregated, and O, Y, Nd, Gd, and Zr elements are segregated on the surface of carbon fiber.
[0036] The graphitized carbon fiber reinforced magnesium matrix composite material prepared in Example 1 was characterized by transmission electron microscopy and energy dispersive spectrometer. Figure 3 As shown by Figure 3 It can be seen that there are multi-layer interfaces in the composite material, in which Y, Nd and Gd elements are segregated in the precipitated phase, Zr and C elements are segregated in the interface near the magnesium matrix (region I), and Y, Nd, Gd and O elements are enriched in the interface near the carbon fiber (region II), and the boundaries between each interface layer are clearly visible.
[0037] The graphitized carbon fiber reinforced magnesium matrix composite material prepared in Example 1 was characterized by transmission electron microscopy and selected area electron diffractometer. Figure 4 As shown by Figure 4 It can be seen that the second phase generated at the interface is magnesium-rare earth phase, which is composed of MgNd, MgGd, Mg 24 Y5 composition; Region 1 is composed of several zirconium carbides with different atomic ratios (ZrC x , 0<x≤1); Region 2 is rare earth sesquioxide RE2O3.
[0038] The thermal conductivity of the graphitized carbon fiber reinforced magnesium-based composite material prepared in Example 1 was tested. The results are as follows: Figure 5 As shown by Figure 5 It can be seen that the thermal conductivity of the composite material reaches 359.620 W / (m·K) at room temperature.
[0039] Example 2
[0040] Preparation of graphitized carbon fiber reinforced magnesium matrix composites
[0041] S1. Ingredients by volume percentage: 28.82 vol.% graphitized carbon fiber, the balance being a Mg-Y-Nd-Gd-Zr alloy; the Mg-Y-Nd-Gd-Zr alloy is composed of the following components by mass percentage: 5 wt.% Y, 3 wt.% Nd, 0.7 wt.% Gd, 0.5 wt.% Zr, unavoidable impurities ≤ 0.25 wt.%, and the balance being Mg;
[0042] S2. Cut the carbon fiber cloth into a size of 150mm×100mm and lay it out in the installed mold. Heat it to 1150℃ and keep it for 2h under a vacuum degree of 0.1Pa, then continue to heat it to 3050℃ and keep it for 1h to obtain graphitized carbon fiber; then add Mg-Y-Nd-Gd-Zr alloy, heat it to 720℃ until the alloy melts, and apply a pressure of 9MPa to make the molten alloy infiltrate into the graphitized carbon fiber, and cool it.
[0043] Example 3
[0044] Preparation of graphitized carbon fiber reinforced magnesium matrix composites
[0045] S1. Ingredients by volume percentage: 37.24 vol.% graphitized carbon fiber, the balance being Mg-Y-Nd-Gd-Zr alloy; the Mg-Y-Nd-Gd-Zr alloy is composed of the following components by mass percentage: 4.5 wt.% Y, 2.2 wt.% Nd, 1.3 wt.% Gd, 0.7 wt.% Zr, unavoidable impurities ≤ 0.25 wt.%, and the balance being Mg;
[0046] S2. Cut the carbon fiber cloth into a size of 150 mm × 100 mm and lay it out in the installed mold. Heat it to 1300 ° C and keep it for 2 hours under a vacuum degree of 0.1 Pa. Then continue to heat it to 2850 ° C and keep it for 1 hour to obtain graphitized carbon fiber. Then add Mg-Y-Nd-Gd-Zr alloy, heat it to 710 ° C until the alloy melts, and apply a pressure of 9 MPa to make the molten alloy infiltrate into the graphitized carbon fiber, and cool it.
[0047] Example 4
[0048] Preparation of graphitized carbon fiber reinforced magnesium matrix composites
[0049] S1. Ingredients by volume percentage: 15.52 vol.% graphitized carbon fiber, the balance being Mg-Y-Nd-Gd-Zr alloy; the Mg-Y-Nd-Gd-Zr alloy is composed of the following components by mass percentage: 3.6 wt.% Y, 1.7 wt.% Nd, 0.8 wt.% Gd, 0.5 wt.% Zr, unavoidable impurities ≤ 0.25 wt.%, and the balance being Mg;
[0050] S2. Cut the carbon fiber cloth into a size of 150 mm × 100 mm and lay it out in the installed mold. Heat it to 1150 ° C and keep it for 2 hours under a vacuum degree of 0.1 Pa. Then continue to heat it to 2850 ° C and keep it for 1 hour to obtain graphitized carbon fiber. Then add Mg-Y-Nd-Gd-Zr alloy, heat it to 700 ° C until the alloy melts, and apply a pressure of 7 MPa to make the molten alloy infiltrate into the graphitized carbon fiber, and cool it.
[0051] The mechanical properties of the graphitized carbon fiber reinforced magnesium-based composite materials prepared in Examples 1 to 3 and the Mg-Y-Nd-Gd-Zr alloy in Example 1 were tested respectively. The results are as follows: Figure 6 As shown by Figure 6 It is known that graphitized carbon fiber reinforced magnesium-based composites have greatly improved mechanical properties compared to simple Mg-Y-Gd-Nd-Zr alloys. Under the premise of keeping rare earth content and zirconium content higher than the minimum standard, its mechanical properties all reach more than 500MPa. In addition, the mechanical properties of composite materials are positively correlated with the volume fraction contained by carbon fiber, and the embodiment 3 of wherein high rare earth content, high carbon fiber volume fraction obtains the most outstanding ultimate tensile strength, which is 682MPa, much higher than the ultimate tensile strength of untreated commercial Mg-Y-Gd-Nd-Zr alloy 176MPa. In addition, it is also known from the elastic phase slope of the stress-strain curve that graphitized carbon fiber reinforced magnesium-based composites have also improved in elastic modulus compared to simple Mg-Y-Gd-Nd-Zr alloys.
[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.
Claims
1. A graphitized carbon fiber reinforced magnesium-based composite material with a multilayer interface structure, characterized in that: The composite material is a zirconium-containing rare earth magnesium alloy dispersed with graphitized carbon fibers, wherein the graphitized carbon fibers are sequentially wrapped from the inside to the outside by a rare earth sesquioxide layer, a zirconium carbide layer and a magnesium rare earth layer.
2. The graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure according to claim 1, characterized in that: The composite material contains at least two rare earth elements of Y, Nd or Gd.
3. The graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure according to claim 2, characterized in that: Calculated by mass percentage, the zirconium content in the composite material is not less than 0.5 wt.%, and the total rare earth element content is not less than 4 wt.%.
4. The graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure according to claim 3, characterized in that: The zirconium-containing rare earth magnesium alloy is one of Mg-Y-Nd-Gd-Zr alloy, Mg-Gd-Nd-Zn-Zr alloy, Mg-Gd-Nd-Mn-Zr alloy, Mg-Y-Gd-Zr alloy or Mg-Y-Nd-Zr alloy.
5. The graphitized carbon fiber reinforced magnesium-based composite material having a multi-layer interface structure according to any one of claims 1 to 4, characterized in that: The graphitized carbon fiber is prepared as follows: Heat the carbon fiber cloth to 1100-1500°C under vacuum conditions and keep it warm for 2-6 hours, then continue to heat it to 2700-3300°C and keep it warm for 1-3 hours.
6. The graphitized carbon fiber reinforced magnesium-based composite material with a multi-layer interface structure according to claim 5, characterized in that: The vacuum condition is specifically: the vacuum degree is not higher than 1×10 -1 Pa.
7. The method for preparing a graphitized carbon fiber reinforced magnesium-based composite material having a multi-layer interface structure according to any one of claims 1 to 6, characterized in that: The preparation method is as follows: Add zirconium-containing rare earth magnesium alloy to the graphitized carbon fiber, heat to 700-750° C. under vacuum conditions until the zirconium-containing rare earth magnesium alloy is melted, apply pressure to allow the molten zirconium-containing rare earth magnesium alloy to infiltrate the graphitized carbon fiber, and cool.
8. The preparation method according to claim 7, wherein The vacuum condition is specifically: the vacuum degree is not higher than 1×10 -1 Pa.
9. The preparation method according to claim 7, wherein The pressurization specifically includes applying a pressure of 6-10 MPa.