Copper-aluminum-magnesium composite material and preparation method and application thereof

Abstract

The invention provides a copper-aluminum-magnesium composite material and a preparation method and application thereof, and belongs to the technical field of copper-aluminum-magnesium composite materials. The preparation method comprises the following steps: 1) mechanically stirring heated semi-solid magnesium to obtain semi-solid slurry; and 2) injecting the semi-solid slurry into a mold in which a copper-aluminum alloy plate and an aluminum foil are preset, and sequentially carrying out rolling, cold rolling and aging treatment to obtain the copper-aluminum-magnesium composite material. Through the synergistic effect of the semi-solid process and the aluminum foil transition layer, the interfacial shear strength of the composite material is improved to 60 MPa or above (only 30-40 MPa in a traditional process), the problem of interfacial stress caused by the difference of thermal expansion coefficients of magnesium and copper-aluminum alloy is effectively solved, and generation of brittle intermetallic compounds is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of copper-aluminum-magnesium composite materials, and in particular to a copper-aluminum-magnesium composite material and a preparation method and application thereof. Background Art

[0002] When metal composites are prepared by traditional solid-state sintering methods, due to differences in the chemical bond types of the metal bonds, the interfacial wettability is poor, resulting in insufficient bonding strength (usually <40 MPa). At the same time, the solid-state diffusion rate is low, making it difficult to completely eliminate pores, and the density of the composite materials is generally less than 95%. Especially during high-temperature sintering, adverse interfacial reactions (such as the formation of brittle phases) are prone to occur between metals, further deteriorating performance. Existing technologies improve wettability by adding active metals, but nanoscale interface regulation is insufficient, and problems of interfacial porosity and stress concentration still exist.

[0003] The thermal expansion coefficients of copper-aluminum alloys (such as Cu-10% Al) and magnesium are significantly different (CuAl: 17×10 -6 / Kvs Mg:25×10 -6 / K), the interface is prone to shear stress under thermal cycle load, which triggers micro cracks and expands. During traditional diffusion welding or hot pressing, Mg-CuAl interface will form Mg 17 Al 12 , MgCu2 and other brittle intermetallic compounds, whose hardness is greater than 500HV but fracture toughness is less than 2MPa·m 1 / 2 Existing technologies use pure aluminum transition layers to alleviate stress, but the layer thickness control accuracy is insufficient (greater than 100μm affects thermal conductivity, and less than 50μm has poor buffering effect), making it difficult to balance strength and reliability.

[0004] The existing methods for combining copper-aluminum alloys with magnesium result in weak interface strength between the two phases, resulting in insufficient strength in the composite material. This limits its application in areas requiring high strength, such as building exteriors, streetlight poles, and automotive battery cases. Therefore, developing a high-strength copper-aluminum-magnesium composite material is a currently unresolved technical challenge. Summary of the Invention

[0005] The purpose of the present invention is to provide a copper-aluminum-magnesium composite material and a preparation method and application thereof, so as to solve the above technical problems.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a copper-aluminum-magnesium composite material, comprising the following steps:

[0008] 1) mechanically stirring the heated semi-solid magnesium to obtain a semi-solid slurry;

[0009] 2) The semi-solid slurry is injected into a mold pre-set with a copper-aluminum alloy plate and an aluminum foil, and rolling, cold rolling and aging treatment are performed in sequence to obtain a copper-aluminum-magnesium composite material.

[0010] Furthermore, the heating temperature of the semi-solid magnesium is 580-620° C., and the solid phase ratio is 40-60%.

[0011] Furthermore, in the step 1), the rotation speed of the mechanical stirring is 300 to 500 rpm, and the time of the mechanical stirring is 10 to 20 minutes.

[0012] Furthermore, the rolling temperature is 550-600° C., and the rolling reduction is 30-50%.

[0013] Furthermore, the deformation amount of the cold rolling is 10-30%, the temperature of the aging treatment is 150-200° C., and the time of the aging treatment is 4-12 hours.

[0014] The present invention also provides a copper-aluminum-magnesium composite material prepared by the above preparation method.

[0015] The present invention also provides an application of a copper-aluminum-magnesium composite material in the fields of buildings, new energy vehicle battery boxes, drone fuselage frames, and equipment casings.

[0016] Beneficial effects of the present invention:

[0017] (1) Significantly improved interface bonding strength

[0018] Through the synergistic effect of the semi-solid process and the aluminum foil transition layer, the interface shear strength of the composite material is increased to more than 60MPa (the traditional process is only 30-40MPa), effectively solving the interface stress problem caused by the difference in thermal expansion coefficients between magnesium and copper-aluminum alloys, and avoiding the formation of brittle intermetallic compounds.

[0019] (2) Excellent mechanical properties

[0020] The compressive strength of the composite material reaches 400-500MPa, the tensile strength is 400-450MPa, and the elongation remains above 5%, which is significantly better than the magnesium-copper-aluminum composite material prepared by the traditional melting and casting method (compressive strength <350MPa).

[0021] (3) High process stability

[0022] The semi-solid stirring technology (580-620°C, solid phase ratio 40-60%) is used to avoid high-temperature melt oxidation and component segregation, significantly improving the slurry uniformity, with a composite material density greater than 98% and a porosity less than 1%. The thermal conductivity of the composite material of the present invention is 150-160 W / (m·K), which is comparable to that of pure magnesium, but the thermal expansion coefficient (18-20×10-6 / K) and copper-aluminum alloy (17×10 -6 / K) is better matched, reducing the risk of interface failure under thermal cycling loads.

[0023] (4) The composite material of the present invention has a lower density than traditional steel / aluminum alloys, achieving a weight reduction of 20-30%. Furthermore, through aging treatment and the use of an aluminum foil transition layer, the salt spray corrosion rate is reduced to 0.02 mm / year, meeting the requirements for long-term outdoor use. It is suitable for applications requiring high strength, lightweight, and durability, such as building curtain walls, battery boxes for new energy vehicles, and drone fuselages. For example, in the construction sector, the composite material exhibits wind pressure resistance of 3 kPa (national standard requirement), with an estimated service life of over 30 years. In the automotive sector, the composite material exhibits no cracks in collision tests, achieving a 30% weight reduction while meeting structural safety requirements. In the drone sector, the composite material exhibits a vibration fatigue life that is doubled, significantly improving reliability. DETAILED DESCRIPTION

[0024] The present invention provides a method for preparing a copper-aluminum-magnesium composite material, comprising the following steps:

[0025] 1) mechanically stirring the heated semi-solid magnesium to obtain a semi-solid slurry;

[0026] 2) The semi-solid slurry is injected into a mold pre-set with a copper-aluminum alloy plate and an aluminum foil, and rolling, cold rolling and aging treatment are performed in sequence to obtain a copper-aluminum-magnesium composite material.

[0027] In the present invention, the heating temperature of the semi-solid magnesium is 580-620° C., preferably 590-610° C., and more preferably 600° C.; the solid phase ratio is 40-60%, and preferably 50%.

[0028] In the present invention, in step 1), the rotation speed of the mechanical stirring is 300-500 rpm, preferably 400 rpm, and the mechanical stirring time is 10-20 min, preferably 15 min. The mechanical stirring is carried out under an inert gas atmosphere, and the inert gas is preferably argon or nitrogen.

[0029] In the present invention, the rolling temperature is 550-600° C., preferably 560-580° C., more preferably 570° C.; the rolling reduction is 30-50%, preferably 35-45%, more preferably 40%.

[0030] In the present invention, the cold rolling deformation is 10-30%, preferably 15-25%, and more preferably 20%; the aging treatment temperature is 150-200°C, preferably 180°C; the aging treatment time is 4-12h, preferably 5-10h, and more preferably 6-8h.

[0031] The present invention also provides a copper-aluminum-magnesium composite material prepared by the above preparation method.

[0032] The present invention also provides an application of a copper-aluminum-magnesium composite material in the fields of buildings, new energy vehicle battery boxes, drone fuselage frames, and equipment casings.

[0033] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1

[0035] 1) Semi-solid magnesium (solid phase ratio 50%) heated to 600° C. was stirred at 400 rpm for 15 minutes under argon protection to obtain a uniform semi-solid slurry.

[0036] 2) The slurry was injected into a mold pre-set with a Cu-10% Al alloy plate and a 50 μm aluminum foil, rolled at 570°C (40% reduction), then cold rolled (20% deformation), and finally aged at 180°C for 8 hours to obtain a composite material.

[0037] The performance test results of the above composite materials are as follows:

[0038] Interface strength: Interface shear strength reaches 69MPa.

[0039] Compressive strength: The compressive strength of the composite material is 450MPa.

[0040] Thermal conductivity: The room temperature thermal conductivity is 156W / (m·K).

[0041] Wind resistance: No deformation after simulating 3kPa wind pressure test, meeting the requirements of building curtain walls.

[0042] Example 2

[0043] 1) Semi-solid magnesium (solid phase ratio 45%) heated to 610° C. was stirred at 350 rpm for 18 minutes under nitrogen protection to obtain a uniform semi-solid slurry.

[0044] 2) The slurry was injected into a mold pre-set with a Cu-10%Al alloy plate and a 50 μm aluminum foil, rolled at 560°C (35% reduction), then cold rolled (25% deformation), and finally aged at 170°C for 10 hours to obtain a composite material.

[0045] The performance test results of the above composite materials are as follows:

[0046] Interface strength: Interface shear strength reaches 72MPa.

[0047] Tensile strength: The composite material has a tensile strength of 420 MPa and an elongation of 5.0%.

[0048] Corrosion resistance: The corrosion rate after 500 hours of salt spray test is 0.02mm / year.

[0049] Example 3

[0050] 1) Semi-solid magnesium (solid fraction 55%) heated to 590° C. was stirred at 450 rpm for 12 minutes under argon protection to obtain a uniform semi-solid slurry.

[0051] 2) The slurry was injected into a mold pre-set with a Cu-10% Al alloy plate and a 50 μm aluminum foil, rolled at 580°C (45% reduction), then cold rolled (15% deformation), and finally aged at 190°C for 6 hours to obtain a composite material.

[0052] The performance test results of the above composite materials are as follows:

[0053] Interface strength: Interface shear strength reaches 65MPa.

[0054] High temperature performance: compressive strength retention rate at 300℃>50%.

[0055] Thermal expansion coefficient: The thermal expansion coefficient of the composite material is 20×10 -6 / K.

[0056] Example 4

[0057] 1) Semi-solid magnesium (solid fraction 55%) heated to 595° C. was stirred at 380 rpm for 17 minutes under argon protection to obtain a uniform semi-solid slurry.

[0058] 2) The slurry was injected into a mold pre-set with a Cu-8%Al alloy plate and a 60 μm aluminum foil, rolled at 565°C (38% reduction), followed by cold rolling (22% deformation), and finally aged at 175°C for 9 hours to obtain a composite material.

[0059] The performance test results of the above composite materials are as follows:

[0060] Interface strength: Interface shear strength reaches 75MPa.

[0061] Compressive strength: 470MPa; thermal conductivity: 158W / (m·K); thermal expansion coefficient: 19×10 -6 / K; Salt spray corrosion rate: 0.018mm / year.

[0062] Application test: Used for street light poles, wind resistance reaches 3.5kPa (exceeding the national standard by 16%)

[0063] Example 5

[0064] 1) Semi-solid magnesium (solid fraction 42%) heated to 615° C. was stirred at 420 rpm for 13 minutes under nitrogen protection to obtain a uniform semi-solid slurry.

[0065] 2) The slurry was injected into a mold pre-set with a Cu-12%Al alloy plate and a 40 μm aluminum foil, rolled at 575°C (42% reduction), then cold rolled (18% deformation), and finally aged at 185°C for 7 hours to obtain a composite material.

[0066] The performance test results of the above composite materials are as follows:

[0067] Interface strength: Interface shear strength reaches 68MPa.

[0068] Tensile strength: 435MPa; elongation: 5.8%; 300℃ high temperature strength retention rate: 55%; interface shear strength: 62MPa.

[0069] Application testing: Used in 5G base station housings, it reduces weight by 25% and improves electromagnetic shielding effectiveness by 20%.

[0070] Example 6

[0071] 1) Semi-solid magnesium (solid fraction 48%) heated to 605° C. was stirred at 360 rpm for 16 minutes in an argon / nitrogen mixed atmosphere to obtain a uniform semi-solid slurry.

[0072] 2) The slurry was injected into a mold pre-set with a Cu-15%Al alloy plate and a 70 μm aluminum foil, rolled at 585°C (45% reduction), followed by cold rolling (28% deformation), and finally aged at 195°C for 5 hours to obtain a composite material.

[0073] The performance test results of the above composite materials are as follows:

[0074] Interface strength: Interface shear strength reaches 70MPa.

[0075] Compressive strength: 490MPa; Vibration fatigue life: 1.5×10 7 times (traditional materials are 5×10 6 Thermal cycling performance (-40~150℃): No interface cracking after 1000 cycles.

[0076] Application testing: Used in high-speed rail carriage connectors, reducing weight by 30% and meeting EN 12663 standards.

[0077] Comparative Example 1 (Traditional Melting and Casting Method)

[0078] The magnesium melt (700° C.) was stirred and then poured without using a semi-solid process. Other steps were the same as in Example 1.

[0079] The performance test results of the composite material are as follows:

[0080] Interface strength: The interface shear strength is only 50MPa.

[0081] The compressive strength is only 300MPa, and a brittle phase is generated at the interface.

[0082] Comparative Example 2 (Traditional Hot Pressing Method)

[0083] Magnesium powder and Cu-10% Al powder were mixed and hot pressed at 500°C / 50 MPa for 2 hours.

[0084] The performance test results of the composite material are as follows:

[0085] Interface strength: The interface shear strength is only 38MPa.

[0086] Compressive strength 320MPa, porosity 8%, a large amount of Mg at the interface 17 Al 12 Mutually.

[0087] As can be seen from the above examples, the present invention provides a copper-aluminum-magnesium composite material, its preparation method, and its application. This invention utilizes a semi-solid-state process to significantly enhance the alloy's interfacial strength and mechanical properties, resulting in a composite material suitable for high-load applications. This composite material is suitable for high-strength, lightweight applications such as buildings, new energy vehicle battery boxes, and drone fuselage frames, exhibiting excellent mechanical properties and durability.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a copper-aluminum-magnesium composite material, characterized in that: The following steps are involved: 1) mechanically stirring the heated semi-solid magnesium to obtain a semi-solid slurry; 2) The semi-solid slurry is injected into a mold pre-placed with a copper-aluminum alloy plate and an aluminum foil, and rolling, cold rolling and aging treatment are performed in sequence to obtain a copper-aluminum-magnesium composite material.

2. The method for preparing the copper-aluminum-magnesium composite material according to claim 1, characterized in that: The heating temperature of the semi-solid magnesium is 580-620° C., and the solid phase ratio is 40-60%.

3. The method for preparing the copper-aluminum-magnesium composite material according to claim 1 or 2, characterized in that: In the step 1), the rotation speed of the mechanical stirring is 300 to 500 rpm, and the time of the mechanical stirring is 10 to 20 minutes.

4. The method for preparing the copper-aluminum-magnesium composite material according to claim 3, characterized in that: The rolling temperature is 550-600° C., and the rolling reduction is 30-50%.

5. The method for preparing the copper-aluminum-magnesium composite material according to claim 1, 2 or 4, characterized in that: The deformation amount of the cold rolling is 10-30%, the temperature of the aging treatment is 150-200° C., and the time of the aging treatment is 4-12 hours.

6. The copper-aluminum-magnesium composite material prepared by the preparation method according to any one of claims 1 to 5.

7. Application of the copper-aluminum-magnesium composite material according to claim 6 in the fields of buildings, new energy vehicle battery boxes, drone fuselage frames, and equipment casings.