A titanium-aluminum-titanium laminated metal composite plate, its processing method and application

Abstract

The present invention relates to the technical field of metal composite materials, and particularly relates to a titanium-aluminum-titanium laminated metal composite plate and its processing method and application. The titanium-aluminum-titanium laminated metal composite plate includes a metal composite plate body, and the metal composite plate body includes a first titanium metal layer, an aluminum metal layer, and a second titanium metal layer; a first interface transition layer is formed between the first titanium metal layer and the aluminum metal layer, and a second interface transition layer is formed between the second titanium metal layer and the aluminum metal layer; the thickness of the metal composite plate body is 0.05 - 0.2 mm. The metal composite plate body is formed by pouring molten aluminum liquid between two solid titanium sheets after thinning treatment, and after solidification, it is successively subjected to diffusion heat treatment and rolling. The thickness of the present invention can be controlled between 0.05 - 0.2 mm, and the ultra-thin thickness makes the composite plate have light weight, high flexibility and excellent mechanical properties, and is suitable for fields with strict requirements on weight and volume. This metal composite plate not only has high strength and good electrical conductivity, but also has excellent corrosion resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of metal composite materials and their processing, and particularly relates to a titanium-aluminum-titanium laminated metal composite plate, its processing method and application. Background Art

[0002] Metal composite materials, as a breakthrough in the performance limitations of traditional single-metal materials, aim to integrate the best characteristics of different metals to create new materials that combine high strength, corrosion resistance, excellent electrical and thermal conductivity. These characteristics make them play a crucial role in many key fields such as aerospace, automotive manufacturing, electronic information, and new energy. Especially in new energy technologies, metal composite materials have shown extraordinary potential in improving the electrical conductivity, stability, and energy density of electrode materials.

[0003] Ultra-thin metal composite materials, as a frontier exploration in the field of metal composite materials, have received extensive attention and research in recent years in the academic and industrial circles. It not only retains the advantages of traditional metal composite materials such as high strength, corrosion resistance, electrical conductivity, and thermal conductivity, but also realizes lightweight, high flexibility, and excellent mechanical properties through precise control of the material thickness, bringing disruptive changes to many high-tech fields.

[0004] In the field of new energy, the application of ultra-thin metal composite materials is particularly important. In the field of lithium-ion batteries, using ultra-thin copper foil or aluminum foil as current collectors can not only significantly reduce the battery volume, improve the energy density, but also maintain excellent electron transport ability, thus extending the cycle life of the battery. In the field of fuel cells, ultra-thin metal composite materials not only help to improve the electrical conductivity and stability of electrode materials, but also accelerate the transport efficiency of reactants by optimizing the design of the gas diffusion layer, thereby comprehensively improving the overall performance of fuel cells.

[0005] In related technologies, there are various preparation methods for ultra-thin metal composite materials, including:

[0006] 1. Welding and bonding method: The principle is to use the regulation of welding solder and welding parameters to achieve the bonding and processing of raw materials and composite materials. It has the advantages of high processing accuracy, high joint strength, and cost savings. Through welding, the composite material can obtain better bending stiffness and strength indicators. Disadvantages: During the welding process, defects such as welding cracks, pores, and solid inclusions may be generated, which will reduce the strength and sealing performance of the composite material. In addition, the heat-affected zone of welding may cause a decline in material properties, especially in high-strength and high-hardness materials. Multiple superimposed welds may also lead to the generation of cracks, making the structure prone to fatigue fracture.

[0007] 2. Fusion method, principle: Two different metal elements are melted together to manufacture metal matrix composites. Generally, the mother sheet is made of one metal element material, and then the surface of the mother sheet is sprayed with another metal element material, and high-temperature heating is used to achieve the fusion of the composite material. Characteristics: The process is relatively simple, but due to the limited quality of the mother sheet and the sprayed material, this method can only be used to manufacture relatively simple metal matrix composites. Disadvantages: The fusion method has high requirements for the quality of raw materials, and factors such as temperature control and time control during the fusion process have a great impact on the quality of the final product. In addition, the fusion method may produce defects such as pores and inclusions, affecting the performance of the composite material.

[0008] 3. Metallurgical method, principle: Metal elements are mixed, dissolved and melted, and then cooled in a high-temperature furnace to make metal matrix composites. It mainly evolves into metal mixtures and metal solid solutions. Characteristics: It can prepare metal matrix composites with complex compositions and excellent properties. Disadvantages: The metallurgical method usually needs to be carried out at high temperatures, with high energy consumption. In addition, problems such as impurities and segregation that may occur during the metallurgical process will also affect the performance of the composite material.

[0009] 4. Hot pressing method, principle: After mixing more than two metal elements, they are plastically deformed under high temperature and pressure to form metal matrix composites. Characteristics: It can manufacture thin sheets, long sheets and flat plates of composite materials, and realize the hot deformation processing of composite materials under limited pressure and temperature conditions, saving labor intensity and improving the gravity strength of products. Disadvantages: The hot pressing method has low productivity and high cost, and due to the action of pressure, the shape of the composite material may be single, making it difficult to meet the needs of products with complex shapes.

[0010] In addition, in the published patent CN108620436B, a titanium-aluminum-copper composite material and its preparation method are disclosed, belonging to the technical field of composite material manufacturing. The titanium-aluminum-copper composite material of the present invention includes a titanium layer, an aluminum layer, and a copper layer arranged in sequence. The preparation method of the titanium-aluminum-copper composite material of the present invention includes the following steps: arranging titanium plates and copper plates at intervals to form a gap between the titanium plates and the copper plates, pouring aluminum liquid into the gap between the titanium plates and the copper plates, and then rolling to obtain the composite material. The titanium-aluminum-copper composite material of the present invention combines the properties of titanium, aluminum, and copper. It not only realizes the substitution of copper with aluminum but also saves titanium with aluminum, and can exhibit the advantages of high conductivity, high thermal conductivity, corrosion resistance, and low cost of the titanium-aluminum-copper composite plate. The titanium-aluminum-copper composite material includes a titanium layer, an aluminum layer, and a copper layer that are sequentially laminated. The thickness of the titanium layer is 0.5 mm. The thickness of the aluminum layer is 2 mm. The thickness of the copper layer is 1.5 mm. The disadvantage of this process is that this process obtains a composite plate by arranging titanium plates and copper plates at intervals, pouring aluminum liquid, and then rolling. However, when preparing ultra-thin metal composite materials, precise control of the thickness becomes particularly difficult. Since the melting points of titanium, aluminum, and copper are different, among which the melting point of titanium is the highest, about 1668 °C, the melting point of aluminum is 660 °C, and the melting point of copper is 1083 °C, this melting point difference will cause thermal expansion mismatch between metal layers during the preparation of the composite material, resulting in stress and deformation during the rolling process. Aluminum liquid has good fluidity during the pouring process, but the solid-state metals of titanium and copper have poor fluidity during rolling. This fluidity difference will cause the aluminum layer to be unable to be evenly distributed during the rolling process, thus affecting the uniformity and thickness control of the composite material. The thermal expansion coefficients of titanium, aluminum, and copper are also different, which may cause internal stress during the heating and cooling processes, thereby affecting the bonding strength and performance of the composite material. Therefore, when the base thickness exceeds 4 mm and the thickness of the titanium layer is 0.5 mm, it is very difficult to obtain an ultra-thin metal composite material with a thickness less than 0.2 mm solely by rolling. Summary of the Invention

[0011] In order to overcome the deficiencies of the prior art, one of the objectives of the present invention is to provide a titanium-aluminum-titanium laminated metal composite plate, the thickness of which can be controlled between 0.05 - 0.2 mm. The ultra-thin thickness makes the composite plate lightweight, highly flexible, and has excellent mechanical properties, suitable for fields with strict requirements for weight and volume. At the same time, this metal composite plate not only has high strength and good electrical conductivity but also has excellent corrosion resistance.

[0012] Another objective of the present invention is to provide a processing method for a titanium-aluminum-titanium laminated metal composite plate. This method successfully manufactures a titanium-aluminum-titanium laminated metal composite plate with a total thickness of only 0.05 - 0.2 mm. The processing process is relatively simple and easy to control, suitable for large-scale industrial production, and has high production efficiency.

[0013] A third object of the present invention is to provide an application of a titanium-aluminum-titanium laminated metal composite plate.

[0014] One of the objects of the present invention is achieved by the following technical solutions:

[0015] The first aspect of the present invention provides a titanium-aluminum-titanium laminated metal composite plate, including a metal composite plate body;

[0016] The metal composite plate body includes a first titanium metal layer, an aluminum metal layer, and a second titanium metal layer that are sequentially laminated from top to bottom; wherein, a first interface transition layer is formed between the first titanium metal layer and the aluminum metal layer, and a second interface transition layer is formed between the second titanium metal layer and the aluminum metal layer;

[0017] The thickness of the metal composite plate body is 0.05 - 0.2 mm, the thickness of the first interface transition layer is 3 - 6 μm, and the thickness of the second interface transition layer is 3 - 6 μm;

[0018] The metal composite plate body is formed by pouring molten aluminum between two solid titanium sheets after thinning treatment, and after solidification, it is sequentially subjected to diffusion heat treatment and rolling.

[0019] In the first aspect of the present invention, as an optional embodiment, the thickness of the metal composite plate body is 0.1 - 0.2 mm; the thickness of the first interface transition layer is 4.5 - 6 μm, and the thickness of the second interface transition layer is 4.5 - 6 μm.

[0020] In the first aspect of the present invention, as an optional embodiment, the thickness ratio of the first titanium metal layer to the aluminum metal layer is 1:(1 - 1.5); the thicknesses of the first titanium metal layer and the second titanium metal layer are the same.

[0021] In the first aspect of the present invention, as an optional embodiment, the thickness of the first titanium metal layer is 0.015 - 0.06 mm, the thickness of the aluminum metal layer is 0.02 - 0.04 mm, and the thickness of the second titanium metal layer is 0.015 - 0.06 mm.

[0022] In the first aspect of the present invention, as an optional embodiment, the bending strength of the metal composite plate body is greater than or equal to 140 MPa, the resistance is less than or equal to 10.5 μΩ·cm, and the corrosion current density is less than or equal to 0.85 μA / cm 2 .

[0023] The second object of the present invention is achieved by the following technical solutions:

[0024] The second aspect of the present invention provides a processing method for a titanium-aluminum-titanium laminated metal composite plate, including:

[0025] S10. Material preparation step: Select solid titanium raw materials and aluminum raw materials; wherein, the solid titanium raw materials are titanium or titanium alloy, and the aluminum raw materials are aluminum or aluminum alloy.

[0026] S20. Thinning treatment step: Thinning the solid titanium raw materials to 0.015 - 0.06 mm through a rolling process to obtain at least two solid titanium sheets.

[0027] S30. Pouring step: Pour molten aluminum liquid between the two solid titanium sheets after the thinning treatment, and let it solidify to obtain a semi - solid composite material structure; control the distance between the two solid titanium sheets to be 0.09 - 0.36 mm.

[0028] S40. Diffusion heat treatment step: Perform diffusion heat treatment on the semi - solid composite material structure.

[0029] S50. Rolling step: Cold - roll the composite material after the diffusion heat treatment. After rolling, a titanium - aluminum - titanium laminated metal composite plate with a thickness of 0.05 - 0.2 mm is obtained.

[0030] In the second aspect of the present invention, as an optional embodiment, in S10, the material preparation step, the thickness of the solid titanium raw materials does not exceed 0.1 mm, and the solid titanium raw materials are in an annealed state; the aluminum raw materials have good fluidity in the molten state.

[0031] In the second aspect of the present invention, as an optional embodiment, in S50, the rolling step, the rolling process is cold - rolling, the rolling force is above 500 MPa, the rolling speed is 1 - 2 m / min, and the rolling deformation per pass does not exceed 20%.

[0032] In the second aspect of the present invention, as an optional embodiment, between step S20 and step S30, there is also step S210, and step S210 includes: annealing the solid titanium sheets after the thinning treatment, the annealing temperature is 490 - 520 °C, the time is 30 - 50 min, and after annealing, air cooling is used for cooling.

[0033] In the second aspect of the present invention, as an optional embodiment, between step S210 and step S30, there is also step S220, and step S220 includes: texturing the surface of the solid titanium sheets after annealing to ensure that its surface is clean and free of impurities.

[0034] In the second aspect of the present invention, as an optional embodiment, in step S220, the texturing treatment is carried out by means of texturing with a titanium texturing machine, sandblasting, shot peening, electro - discharge machining or laser. After texturing, the surface roughness Ra of the solid titanium sheets is 3 - 5.

[0035] In the second aspect of the present invention, as an alternative embodiment, after the texturing treatment is completed, the surface of the solid titanium sheet is cleaned by ultrasonic cleaning. After cleaning, the surface of the solid titanium sheet is dried by air drying or in a drying oven to ensure that the metal surface is clean without impurities and water stains.

[0036] In the second aspect of the present invention, as an alternative embodiment, in step S30, the pouring step, first, two solid titanium sheets are preheated to 590 - 610 °C and fixed at a preset spacing respectively; then the aluminum raw material is melted, kept at 670 - 690 °C for heat preservation, left standing and slag removed to ensure the quality of the molten aluminum; finally, the molten aluminum is poured between the two solid titanium sheets and allowed to solidify to obtain a semi-solid composite material structure.

[0037] In the second aspect of the present invention, as an alternative embodiment, in step S40, the diffusion heat treatment step, the treatment temperature is 350 - 420 °C, the time is 30 - 130 min, and the cooling method is air cooling.

[0038] In the second aspect of the present invention, as an alternative embodiment, in step S50, the rolling step,

[0039] When the thickness of the titanium-aluminum-titanium laminated metal composite plate is controlled to be 0.05 mm, the thickness changes during the rolling process are 0.12 mm, 0.096 mm, 0.077 mm, 0.061 mm, 0.05 mm in sequence;

[0040] When the thickness of the titanium-aluminum-titanium laminated metal composite plate is controlled to be 0.1 mm, the thickness changes during the rolling process are 0.24 mm, 0.192 mm, 0.154 mm, 0.122 mm, 0.1 mm in sequence;

[0041] When the thickness of the titanium-aluminum-titanium laminated metal composite plate is controlled to be 0.2 mm, the thickness changes during the rolling process are 0.48 mm, 0.384 mm, 0.308 mm, 0.244 mm, 0.2 mm in sequence.

[0042] The third object of the present invention is achieved by the following technical solution:

[0043] The third aspect of the present invention provides a bipolar plate, which is made of the titanium-aluminum-titanium laminated metal composite plate of the first aspect of the present invention.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] 1. The present invention includes a first titanium metal layer, an aluminum metal layer, and a second titanium metal layer. The three-layer structure combines the high strength and corrosion resistance of titanium with the excellent electrical and thermal conductivity of aluminum, enabling the metal composite plate to have comprehensive excellent properties. A first interface transition layer is formed between the first titanium metal layer and the aluminum metal layer, and a second interface transition layer is formed between the second titanium metal layer and the aluminum metal layer. The interface transition layer enhances the bonding strength between the titanium layer and the aluminum layer, improving the overall stability and durability of the metal composite plate. The thickness of the metal composite plate can be controlled between 0.05 - 0.2 mm. The ultra-thin thickness makes the composite plate lightweight, highly flexible, and has excellent mechanical properties, suitable for fields with strict requirements for weight and volume. At the same time, the metal composite plate not only has high strength and good electrical conductivity but also excellent corrosion resistance.

[0046] 2. The present invention proposes a new processing method for a titanium-aluminum-titanium layered metal composite plate. This method uses a unique process of first rolling the raw material thinner, then performing semi-solid composite, and finally rolling the composite material again to thin it, successfully manufacturing a titanium-aluminum-titanium layered metal composite plate with a total thickness of only 0.05 - 0.2 mm. This composite material not only has excellent mechanical properties and processing properties but also achieves good interfacial bonding, avoiding interfacial problems in traditional composite processes. After the bipolar plate is manufactured, its flexural strength is greater than or equal to 140 MPa, the resistance is less than or equal to 10.5 μΩ·cm, and the corrosion current density is less than or equal to 0.85 μA / cm². In addition, this method is relatively simple and easy to control, suitable for large-scale industrial production, and has high production efficiency. Due to the excellent property complementarity of titanium and aluminum, this composite material has broad application prospects in many fields such as aerospace, medical devices, electronic equipment, and automotive manufacturing. At the same time, this preparation method is relatively environmentally friendly and sustainable, providing strong technical support and promotion for the development of related industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a process schematic diagram of the processing method of the titanium-aluminum-titanium layered metal composite plate of the present invention;

[0048] Figure 2 is a structural schematic diagram of the thinning of the titanium raw material;

[0049] Figure 3 is a structural schematic diagram of the semi-solid composite;

[0050] Figure 4 is a structural schematic diagram of the product after the semi-solid composite is completed;

[0051] Figure 5a is an interfacial microstructure diagram of the first interface transition layer of the titanium-aluminum-titanium layered metal composite plate of Example 1 of the present invention;

[0052] Figure 5bInterface microstructure diagram of the second interface transition layer of the titanium-aluminum-titanium laminated metal composite plate of Embodiment 1 of the present invention;

[0053] Figure 6a Interface microstructure diagram of the first interface transition layer of the titanium-aluminum-titanium laminated metal composite plate of Embodiment 2 of the present invention;

[0054] Figure 6b Interface microstructure diagram of the second interface transition layer of the titanium-aluminum-titanium laminated metal composite plate of Embodiment 2 of the present invention;

[0055] Figure 7a Interface microstructure diagram of the first interface transition layer of the titanium-aluminum-titanium laminated metal composite plate of Comparative Example 1 of the present invention;

[0056] Figure 7b Interface microstructure diagram of the second interface transition layer of the titanium-aluminum-titanium laminated metal composite plate of Comparative Example 1 of the present invention. Detailed implementation manners

[0057] Next, in combination with the accompanying drawings and specific implementation manners, the present invention will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments. Except as otherwise specified, the materials and equipment used in this embodiment can be purchased from the market.

[0058] Please refer to Figures 1 - 7b , the first aspect of the present invention provides a titanium-aluminum-titanium laminated metal composite plate, including a metal composite plate body;

[0059] The metal composite plate body includes a first titanium metal layer, an aluminum metal layer, and a second titanium metal layer that are sequentially laminated from top to bottom; wherein, a first interface transition layer is formed between the first titanium metal layer and the aluminum metal layer, and a second interface transition layer is formed between the second titanium metal layer and the aluminum metal layer;

[0060] The thickness of the metal composite plate body is 0.05 - 0.2 mm, the thickness of the first interface transition layer is 3 - 6 μm, and the thickness of the second interface transition layer is 3 - 6 μm.

[0061] On the basis of the above solution, the present invention includes a first titanium metal layer, an aluminum metal layer, and a second titanium metal layer. The three-layer structure combines the high strength and corrosion resistance of titanium with the excellent electrical and thermal conductivity of aluminum, enabling the metal composite plate to have comprehensive excellent properties. A first interface transition layer is formed between the first titanium metal layer and the aluminum metal layer, and a second interface transition layer is formed between the second titanium metal layer and the aluminum metal layer. The interface transition layer enhances the bonding strength between the titanium layer and the aluminum layer, improving the overall stability and durability of the metal composite plate. The thickness of the metal composite plate can be controlled between 0.05 - 0.2 mm. The ultra-thin thickness makes the composite plate lightweight, highly flexible, and has excellent mechanical properties, suitable for fields with strict requirements for weight and volume. At the same time, the metal composite plate not only has high strength and good electrical conductivity but also excellent corrosion resistance.

[0062] As a preferred embodiment, the metal composite plate body is formed by pouring molten aluminum between two solid titanium sheets after thinning treatment. After solidification, it is then subjected to diffusion heat treatment and rolling in sequence.

[0063] On the basis of the above solution, the present invention first makes the titanium sheet have a moderate thickness through thinning treatment, which is convenient for subsequent processing and compounding; pours the molten aluminum between two solid titanium sheets to ensure uniform distribution of the aluminum liquid, and then allows the aluminum liquid to solidify. Utilizing the fluidity of the aluminum liquid, it is poured and solidified between the titanium sheets to achieve the preliminary compounding of the aluminum layer and the titanium layer; performs diffusion heat treatment on the preliminary composite structure to promote the element diffusion between the titanium metal layer and the aluminum metal layer, forming an interface transition layer and enhancing the bonding strength; finally, performs rolling treatment on the composite structure after diffusion heat treatment to further reduce the thickness of the composite plate, improve its density and mechanical properties. Through plastic deformation during the rolling process, the thickness of the composite plate is reduced, while the density and mechanical properties of the material are improved.

[0064] As a preferred embodiment, the thickness of the metal composite plate body is 0.1 - 0.2 mm; the thickness of the first interface transition layer is 4.5 - 6 μm, and the thickness of the second interface transition layer is 4.5 - 6 μm. More preferably, the thickness of the first interface transition layer is 4.5 - 5.8 μm, and the thickness of the second interface transition layer is 4.5 - 5.8 μm.

[0065] As a preferred embodiment, the thickness ratio of the first titanium metal layer to the aluminum metal layer is 1:(1 - 1.5); the first titanium metal layer and the second titanium metal layer have the same thickness.

[0066] Based on the above solution, the present invention can optimize the mechanical properties, electrical conductivity, and corrosion resistance of the composite plate by precisely controlling the thickness ratio of each layer. The titanium layer provides high strength and corrosion resistance, while the aluminum layer provides excellent electrical and thermal conductivity. A thickness ratio of the titanium metal layer to the aluminum metal layer of 1:(1 - 1.5) can achieve the best balance of these properties. Since the density of aluminum is lower than that of titanium, by increasing the thickness of the aluminum layer (within a preset range), the weight of the composite plate can be reduced while maintaining sufficient strength. The same thickness of the titanium layer simplifies the processing process, making the preparation of the composite plate more efficient and stable, and ensuring the structural symmetry of the composite plate, which helps to improve its overall performance and stability.

[0067] As a preferred embodiment, the thickness of the first titanium metal layer is 0.015 - 0.06 mm, the thickness of the aluminum metal layer is 0.02 - 0.04 mm, and the thickness of the second titanium metal layer is 0.015 - 0.06 mm.

[0068] As a preferred embodiment, the flexural strength of the metal composite plate body is greater than or equal to 140 MPa, the resistivity is less than or equal to 10.5 μΩ·cm, and the corrosion current density is less than or equal to 0.85 μA / cm 2 。

[0069] Please refer to Figures 1 - 7b , the second aspect of the present invention provides a processing method for a titanium-aluminum-titanium layered metal composite plate, including:

[0070] S10. Material preparation step: Select solid titanium raw materials and select aluminum raw materials; wherein, the solid titanium raw materials are titanium or titanium alloy, and the aluminum raw materials are aluminum or aluminum alloy;

[0071] S20. Thinning treatment step: Thinning the solid titanium raw materials to 0.015 - 0.06 mm through a rolling process to obtain at least two solid titanium sheets;

[0072] S30. Pouring step: Pour molten aluminum liquid between the two solid titanium sheets after the thinning treatment and let it solidify to obtain a semi-solid composite material structure; control the distance between the two solid titanium sheets to be 0.09 - 0.36 mm;

[0073] S40. Diffusion heat treatment step: Perform diffusion heat treatment on the semi-solid composite material structure;

[0074] S50. Rolling step: Cold roll the composite material after the diffusion heat treatment, and after rolling, obtain a titanium-aluminum-titanium layered metal composite plate with a thickness of 0.05 - 0.2 mm.

[0075] Based on the above solution, the present invention first makes the titanium sheet have a moderate thickness through thinning treatment, which is convenient for subsequent processing and lamination; pouring molten aluminum liquid between two solid titanium sheets to ensure uniform distribution of the aluminum liquid, and then allowing the aluminum liquid to solidify. By taking advantage of the fluidity of the aluminum liquid, it is poured and solidified between the titanium sheets to achieve the preliminary lamination of the aluminum layer and the titanium layer; performing diffusion heat treatment on the preliminary laminated structure to promote the element diffusion between the titanium metal layer and the aluminum metal layer, forming an interfacial transition layer and enhancing the bonding strength; finally, performing rolling treatment on the laminated structure after diffusion heat treatment to further reduce the thickness of the composite plate, improve its density and mechanical properties. Through plastic deformation during the rolling process, the thickness of the composite plate is reduced, and at the same time, the density and mechanical properties of the material are improved.

[0076] As a preferred embodiment, in step S10, the material preparation step, the thickness of the solid titanium raw material does not exceed 0.1 mm, and the solid titanium raw material is in an annealed state; the aluminum raw material has good fluidity in a molten state.

[0077] Based on the above solution, titanium and titanium alloy materials with an initial thickness not exceeding 0.1 mm provide a good foundation for subsequent rolling thinning and lamination processes, which helps to reduce processing difficulty and cost. Annealing treatment eliminates the work hardening of titanium and titanium alloy materials, improves their plasticity and workability, and makes the materials easier to deform and bond during subsequent rolling and lamination processes. In a molten state, aluminum or aluminum alloy has good fluidity, can uniformly fill the gaps between titanium alloy plates, form a complete laminated layer, and improve the bonding strength and lamination quality of the laminated interface.

[0078] As a preferred embodiment, in step S20, the thinning treatment step, the rolling process is cold rolling, and the rolling deformation per pass does not exceed 20%.

[0079] Based on the above solution, the cold rolling process can plastically deform metals without heating, avoiding defects such as oxide scale and decarburization that may occur during the heating process, thus ensuring the surface finish and quality of the material. The cold rolling process can precisely control the thickness and size of the material to meet the requirements of high-precision processing. During the cold rolling process, the grains of the metal material are refined, the structure is more compact, and the strength and toughness of the material are improved. Controlling the rolling deformation per pass within 20% can effectively reduce the internal stress and deformation resistance generated during rolling, reduce the risk of crack generation, and avoid fracture or scrapping of the material due to excessive deformation, thereby improving the material utilization rate.

[0080] As a preferred embodiment, between step S20 and step S30, there is also included step S210, and step S210 includes: annealing the thinned solid titanium sheet material, with the annealing temperature being 490 - 520 °C, the time being 30 - 50 min, and after the annealing is completed, air cooling is used for cooling.

[0081] Based on the above solution, at an annealing temperature of 490 °C - 520 °C, the internal structure of the titanium or titanium alloy material can undergo appropriate recovery and recrystallization, eliminating work hardening and improving the plasticity and workability of the material. Controlling the annealing temperature within the above range can avoid overburning of the material due to too high a temperature, which would damage the material's properties. Maintaining the annealing time at 30 - 50 minutes can ensure that the titanium or titanium alloy material has sufficient time for recovery and recrystallization to reach an ideal microstructure state. The air cooling method enables the material to cool evenly after annealing, avoiding stress or cracks caused by rapid cooling. The air cooling method does not require additional cooling equipment, simplifies the heat treatment process, and reduces production costs.

[0082] As a preferred embodiment, between step S210 and step S30, there is also included step S220, and step S220 includes: texturing the surface of the annealed solid titanium sheet material to ensure that its surface is clean and free of impurities.

[0083] Based on the above solution, through texturing treatment, a microscopic morphology with a certain roughness is formed on the titanium surface, increasing the contact area with the subsequent composite material, thereby enhancing the interfacial bonding force. The texturing treatment improves the wettability of the titanium surface, making it easier for the molten aluminum or aluminum alloy to spread and penetrate evenly during the composite process, improving the composite quality.

[0084] As a preferred embodiment, in step S220, the texturing treatment is carried out by means of texturing with a titanium texturing machine, sandblasting, shot peening, electric discharge machining, or laser, and after the texturing is completed, the surface roughness Ra of the solid titanium sheet material is 3 - 5.

[0085] Titanium texturing machine: The titanium texturing machine mechanically treats the titanium surface through specific process parameters and texturing tools to form a microscopic morphology with a certain roughness.

[0086] Sandblasting, shot peening: Using high-speed jetting of sand grains or shot grains to impact the titanium surface, causing the surface to have an uneven morphology.

[0087] Electric discharge machining, laser: Through electric discharge machining or laser irradiation, locally melting or vaporizing the titanium surface to form a rough surface.

[0088] As a preferred embodiment, after the texturing treatment, the surface of the solid titanium sheet is cleaned by ultrasonic cleaning. After cleaning, the surface of the solid titanium sheet is dried by air drying or using a drying oven to ensure that the metal surface is clean without impurities and water stains.

[0089] Ultrasonic cleaning utilizes the cavitation effect, acceleration effect, and rectilinear flow effect of ultrasonic waves in a liquid to directly and indirectly act on the liquid and dirt, dispersing, emulsifying, and peeling the dirt layer to achieve the cleaning purpose. This cleaning method can thoroughly remove impurities such as oil and dust on the metal surface, ensuring a clean surface. Ultrasonic cleaning causes no mechanical damage to the metal surface, maintaining the integrity and smoothness of the metal surface.

[0090] Drying by air drying or using a drying oven can quickly remove the moisture on the metal surface, ensuring that the metal surface is clean without impurities and water stains, providing good conditions for subsequent processing and composite processes. The drying process is fast and effective, improving production efficiency and reducing production costs.

[0091] As a preferred embodiment, in step S30, the casting step, first, two solid titanium sheets are preheated to 590 - 610 °C and fixed at a preset spacing respectively; then the aluminum raw material is melted and held at 670 - 690 °C, allowed to stand and skimmed; finally, the molten aluminum liquid is poured between the two solid titanium sheets and allowed to solidify to obtain a semi-solid composite material structure.

[0092] Based on the above solution, when preheating titanium or titanium alloy to 590 - 610 °C, when the temperature is less than 590 °C, the atomic activity ability inside the metal is limited, and the mutual diffusion rate between atoms is slow, which is not conducive to the formation of metallurgical bonding. Therefore, at low-temperature preheating, the interfacial bonding force of the titanium-aluminum-titanium laminated composite metal plate is weak. When the preheating temperature gradually increases to 600 °C, the atomic activity ability inside the metal increases, and the mutual diffusion rate between atoms accelerates, which is conducive to the formation of metallurgical bonding. When the preheating temperature exceeds 610 °C, although the atomic activity ability inside the metal is further enhanced, it also causes softening or excessive recrystallization of the metal matrix, reducing the interfacial bonding strength and thus affecting the overall mechanical properties of the titanium-aluminum-titanium laminated composite metal plate. Holding at 670 - 690 °C and allowing to stand and skim can remove impurities and gases in the aluminum liquid, ensuring the purity and quality of the melt.

[0093] As a preferred embodiment, in step S40, the diffusion heat treatment step, the treatment temperature is 350 - 420 °C, the time is 30 - 130 min, and the cooling method is air cooling.

[0094] When the temperature is less than 350 °C, the atoms inside the material do not undergo an effective diffusion process, and the increase in the thickness of the diffusion layer is small, resulting in a small interfacial bonding force. As the diffusion heat treatment temperature increases, when the temperature reaches the range of 350 - 420 °C, the thickness of the diffusion layer between the titanium layer and the aluminum layer will gradually increase. The increase in the thickness of the diffusion layer means that more atoms have diffused and reacted at the interface, thereby enhancing the metallurgical bonding force at the interface. When the temperature is greater than 420 °C, on the one hand, the excessive temperature may cause softening or excessive recrystallization of the metal matrix, reducing the mechanical properties of the matrix and thus affecting the bonding strength of the interface. On the other hand, the too thick intermetallic compound layer may increase the brittleness of the interface and reduce the toughness of the interface, making the interface more prone to fracture when subjected to external forces. Within this time range, the full progress of the diffusion process can be ensured. In the diffusion heat treatment, the air cooling method can avoid the internal stress generated by rapid cooling and is beneficial to maintaining the performance stability of the material.

[0095] As a preferred embodiment, in S50, the rolling step, the rolling process is cold rolling, the rolling force is above 500 MPa, the rolling speed is 1 - 2 m / min, and the rolling deformation per pass does not exceed 20%.

[0096] As a preferred embodiment, in S50, the rolling step

[0097] When the thickness of the titanium-aluminum-titanium laminated metal composite plate is controlled to be 0.05 mm, the thickness changes during the rolling process are 0.12 mm, 0.096 mm, 0.077 mm, 0.061 mm, and 0.05 mm in sequence;

[0098] When the thickness of the titanium-aluminum-titanium laminated metal composite plate is controlled to be 0.1 mm, the thickness changes during the rolling process are 0.24 mm, 0.192 mm, 0.154 mm, 0.122 mm, and 0.1 mm in sequence;

[0099] When the thickness of the titanium-aluminum-titanium laminated metal composite plate is controlled to be 0.2 mm, the thickness changes during the rolling process are 0.48 mm, 0.384 mm, 0.308 mm, 0.244 mm, and 0.2 mm in sequence.

[0100] On the basis of the above scheme, the reduction per pass is different, but generally shows a gradually decreasing trend. This is because during cold rolling, as the thickness of the material decreases, its deformation resistance gradually increases. Therefore, it is necessary to gradually reduce the reduction per pass to avoid excessive rolling force causing equipment damage or material cracking.

[0101] The third aspect of the present invention provides a bipolar plate, which is manufactured by using the titanium-aluminum-titanium laminated metal composite plate of the first aspect of the present invention.

[0102] The following are some embodiments listed in this application, and this application will be further described through the following embodiments. Embodiment

[0103] A processing method for a titanium-aluminum-titanium laminated metal composite plate, comprising:

[0104] S10. Material preparation step: Select solid titanium raw materials and aluminum raw materials; wherein, the solid titanium raw materials are TA1 titanium alloy, and the aluminum raw materials are 6063 aluminum alloy; the thickness of the solid titanium raw materials does not exceed 0.1 mm, and the solid titanium raw materials are in the annealed state; the aluminum raw materials have good fluidity in the molten state.

[0105] S20. Thinning treatment step: Thinning the solid titanium raw materials to 0.03 mm through a rolling process to obtain at least two solid titanium sheets; the rolling process is cold rolling, and the rolling deformation per pass does not exceed 20%, and no cracks or other tissue defects should occur during the rolling process; the thickness changes during the rolling process are 0.1 mm, 0.08 mm, 0.064 mm, 0.0512 mm, 0.0409 mm, 0.032 mm, 0.03 mm in sequence;

[0106] S210. Anneal the solid titanium sheets after the thinning treatment, the annealing temperature is 520 °C, the time is 30 min, and air cooling is used for cooling after annealing;

[0107] S220. Texturize the surface of the solid titanium sheets after annealing to ensure that its surface is clean and free of impurities. The texturing treatment is carried out by means of texturing with a titanium texturing machine, sandblasting, shot peening, electric spark or laser. After texturing, the surface roughness Ra of the solid titanium sheets is 4; after the texturing treatment, clean the surface of the solid titanium sheets by ultrasonic cleaning. After cleaning, dry the surface of the solid titanium sheets by air drying or using a drying oven to ensure that the metal surface is clean and free of impurities and water stains;

[0108] S30. Pouring step: First preheat two solid titanium sheets to 600 °C and fix them at a spacing of 0.18 mm respectively; then melt the aluminum raw materials, keep them at 680 °C for heat preservation, stand still and skim the slag to ensure the quality of the aluminum liquid melt; finally pour the molten aluminum liquid between the two solid titanium sheets and let it solidify to obtain a semi-solid composite material structure;

[0109] S40. Diffusion heat treatment step: Carry out diffusion heat treatment on the semi-solid composite material structure; the treatment temperature is 420 °C, the time is 40 min, and the cooling method is air cooling;

[0110] S50. Rolling Step: Cold roll the composite material after diffusion heat treatment. After rolling is completed, a titanium-aluminum-titanium laminated metal composite plate with a thickness of 0.1 mm is obtained. The rolling process is cold rolling, the rolling force is 515 MPa, the rolling speed is 1.5 m / min, the rolling deformation per pass is 20%, and the thickness changes during the rolling process are 0.24 mm, 0.192 mm, 0.154 mm, 0.122 mm, and 0.1 mm in sequence.

[0111] Performance Testing

[0112] 1. Use a field emission scanning electron microscope (FE-SEM) to test the average thickness of the titanium-aluminum transition layer. The specific test experiment is as follows:

[0113] Environmental Conditions: Temperature 23 ± 2 °C, Humidity: 50 ± 10%RH;

[0114] Test Standard: TestStandard: ASTM B748-90 (Reapproved 021).

[0115] Test Conditions: First, embed, grind, and polish the sample, then plate the cross-section with Pt for 25 s, and place it in the sample chamber of the scanning electron microscope according to the standard operation procedure to magnify and observe the test position and measure the thickness.

[0116] Test Results: See Figure 5a and Figure 5b , the average thickness of the first interface transition layer in the titanium-aluminum-titanium laminated composite metal plate of this embodiment is about 4.8 μm, and the average thickness of the second interface transition layer is about 5 μm.

[0117] Refer to the peeling method in GJB 446-1988 for testing. The peeling strength is the interface bonding force of this embodiment. Use GB / T 228.1-2010 to test the tensile strength and yield strength, use GB / T 351-2019 "Measurement Method for Resistivity of Metallic Materials" to test the resistivity, and use an electrochemical workstation for potentiodynamic polarization testing to obtain the corrosion current density. Detect the performance of the titanium-aluminum-titanium laminated composite metal plate described in Example 1 above, as shown in Table 1 below.

[0118] Table 1: Performance Test Results of the Titanium-Aluminum-Titanium Laminated Composite Metal Plate of Example 1

[0119]

[0120] On the basis of Example 1 above, the influence of different preheating temperatures on the performance of the titanium-aluminum-titanium laminated composite metal plate was further explored. During this process, different preheating temperatures were set, but other conditions were kept the same as in Example 1. The performance of the titanium-aluminum-titanium laminated composite metal plate with specific preheating temperature settings is shown in Table 2.

[0121] Table 2: Results of the influence of preheating temperature on the properties of titanium-aluminum-titanium laminated composite metal plates

[0122]

[0123] As can be seen from Table 2 above, when the temperature is less than 590 °C, the atomic activity within the metal is limited, and the mutual diffusion rate between atoms is slow, which is not conducive to the formation of metallurgical bonding. Therefore, at low-temperature preheating, the interfacial bonding force of the titanium-aluminum-titanium laminated composite metal plate is weak. When the preheating temperature gradually increases to 600 °C, the atomic activity within the metal increases, and the mutual diffusion rate between atoms accelerates, which is conducive to the formation of metallurgical bonding. When the preheating temperature exceeds 610 °C, although the atomic activity within the metal further increases, it also causes softening or excessive recrystallization of the metal matrix, which will reduce the bonding strength at the interface, thereby affecting the overall mechanical properties of the titanium-aluminum-titanium laminated composite metal plate.

[0124] On the basis of Example 1 above, the influence of the temperature of different diffusion heat treatments on the properties of the titanium-aluminum-titanium laminated composite metal plate was further explored. During this process, different temperatures of diffusion heat treatments were set, but other conditions were kept the same as in Example 1. The specific temperature settings of the diffusion heat treatments and the property conditions of the titanium-aluminum-titanium laminated composite metal plates are shown in Table 3.

[0125] Table 3: Results of the influence of the temperature of diffusion heat treatment on the properties of titanium-aluminum-titanium laminated composite metal plates

[0126]

[0127] As can be seen from Table 3 above, when the temperature is less than 350 °C, the atoms within the material do not undergo an effective diffusion process, and the increase in the thickness of the diffusion layer is small, resulting in a small interfacial bonding force; as the temperature of the diffusion heat treatment increases, when the temperature reaches the range of 350 - 420 °C, the thickness of the diffusion layer between the titanium layer and the aluminum layer will gradually increase. The increase in the thickness of the diffusion layer means that more atoms have diffused and reacted at the interface, thereby enhancing the metallurgical bonding force at the interface. When the temperature is greater than 420 °C, on the one hand, the excessively high temperature may cause softening or excessive recrystallization of the metal matrix, reducing the mechanical properties of the matrix, thereby affecting the bonding strength at the interface. On the other hand, the excessively thick intermetallic compound layer may increase the brittleness of the interface and reduce the toughness of the interface, making the interface more prone to fracture when subjected to external forces.

[0128] On the basis of Example 1 above, the influence of the time of diffusion heat treatment on the properties of the titanium-aluminum-titanium laminated composite metal plate was further explored. During this process, different times of diffusion heat treatments were set, but other conditions were kept the same as in Example 1. The specific time settings of the diffusion heat treatments and the property conditions of the titanium-aluminum-titanium laminated composite metal plates are shown in Table 4.

[0129] Table 4: Results of the influence of diffusion heat treatment time on the properties of titanium-aluminum-titanium laminated composite metal plates

[0130]

[0131] As can be seen from Table 4 above, when the temperature is constant, as the time increases, the thickness of the diffusion layer gradually increases, and the interfacial bonding force gradually increases. However, after 130 minutes, the diffusion at the interface is relatively complete. Continuing to extend the time, the interfacial bonding force tends to be stable, while with the increase of time, the energy consumption cost and processing time both increase correspondingly.

[0132] On the basis of the above-mentioned Example 1, the influence of the rolling force in the rolling step on the properties of the titanium-aluminum-titanium laminated composite metal plates was further explored. In this process, different rolling forces in the rolling step were set, but other conditions were kept the same as in Example 1. For the specific setting of the rolling force in the rolling step and the performance of the titanium-aluminum-titanium laminated composite metal plates, see Table 5.

[0133] Table 5: Results of the influence of the rolling force in the rolling step on the properties of the titanium-aluminum-titanium laminated composite metal plates

[0134]

[0135] As can be seen from Table 5 above, when the rolling force is less than 500 MPa, the contact pressure between the titanium layer and the aluminum layer is insufficient, and it is difficult to effectively overcome the influence of surface roughness and oxide layer, so the interfacial bonding force is weak. With the increase of the rolling force, the degree of plastic deformation of the material increases, the interfacial contact area increases, and the bonding force gradually increases. When the rolling force reaches 515 MPa, the interfacial bonding force reaches the maximum value. At this time, the rolling force can fully promote the close contact and plastic deformation between the interfaces, and at the same time avoid material damage or the formation of brittle phases at the interfaces caused by excessive rolling force, so as to achieve the best interfacial bonding effect. When the rolling force exceeds 515 MPa, the interfacial bonding force begins to decrease. This is because excessive rolling force causes excessive deformation of the material, resulting in stress concentration or the generation of microcracks at the interfaces, weakening the interfacial bonding strength. In addition, too high rolling force may also damage the metallurgical bonding at the interfaces, resulting in a decrease in bonding performance.

[0136] On the basis of the above-mentioned Example 1, the influence of the rolling speed in the rolling step on the properties of the titanium-aluminum-titanium laminated composite metal plates was further explored. In this process, different rolling speeds in the rolling step were set, but other conditions were kept the same as in Example 1. For the specific setting of the rolling speed in the rolling step and the performance of the titanium-aluminum-titanium laminated composite metal plates, see Table 6.

[0137] Table 6: Results of the influence of the rolling speed in the rolling step on the properties of the titanium-aluminum-titanium laminated composite metal plates

[0138]

[0139] As can be seen from Table 6 above, during low-speed rolling, the titanium layer and the aluminum layer have sufficient time to come into contact and undergo plastic deformation, and the interfacial bonding force gradually increases with the increase of the rolling speed. At this time, the material can better overcome the influence of surface roughness and oxide layer during the rolling process, promoting interfacial bonding. When the rolling speed reaches 1.5 m / min, the interfacial bonding force reaches the maximum value. At this time, the rolling speed can not only ensure sufficient plastic deformation and interfacial contact, but also avoid problems such as insufficient interfacial temperature rise or uneven deformation caused by too fast speed, thus achieving the best interfacial bonding effect. When the rolling speed exceeds 2 m / min, the interfacial bonding force begins to decline. This is because too fast rolling speed results in insufficient material deformation time, insufficient interfacial temperature rise and atomic diffusion, making it difficult to form a stable metallurgical bond. At the same time, high-speed rolling may cause local stress concentration or uneven deformation, further weakening the interfacial bonding force.

[0140] Example 2:

[0141] A processing method for a titanium-aluminum-titanium laminated metal composite plate, comprising:

[0142] S10. Material preparation step: Select solid titanium raw materials and select aluminum raw materials; wherein, the solid titanium raw materials are TA1 titanium alloy, and the aluminum raw materials are 6063 aluminum alloy; the thickness of the solid titanium raw materials does not exceed 0.2 mm, and the solid titanium raw materials are in the annealed state; the aluminum raw materials have good fluidity in the molten state.

[0143] S20. Thinning treatment step: Thinning the solid titanium raw materials to 0.06 mm through a rolling process to obtain at least two solid titanium sheets; the rolling process is cold rolling, and the rolling deformation per pass does not exceed 20%. No cracks or other tissue defects should appear during the rolling process; the thickness changes during the rolling process are 0.2 mm, 0.16 mm, 0.128 mm, 0.1024 mm, 0.0818 mm, 0.064 mm, 0.06 mm in sequence;

[0144] S210. Anneal the solid titanium sheets after the thinning treatment. The annealing temperature is 520 °C and the time is 30 min. After annealing, air cooling is used for cooling;

[0145] S220. Perform surface texturing on the surface of the annealed solid titanium sheets to ensure that their surfaces are clean and free of impurities. The texturing treatment is carried out by means of texturing with a titanium texturing machine, sandblasting, shot peening, electric spark or laser. After texturing, the surface roughness Ra of the solid titanium sheets is 4; after the texturing treatment is completed, the surface of the solid titanium sheets is cleaned by ultrasonic cleaning. After cleaning, the surface of the solid titanium sheets is dried by air drying or in a drying oven to ensure that the metal surface is clean and free of impurities and water stains;

[0146] S30. Pouring step: First, preheat two solid titanium sheets to 600 °C and fix them separately at a spacing of 0.36 mm. Then, melt the aluminum raw material, keep it at 680 °C for heat preservation, let it stand and skim the slag to ensure the quality of the molten aluminum. Finally, pour the molten aluminum between the two solid titanium sheets and let it solidify to obtain a semi-solid composite material structure.

[0147] S40. Diffusion heat treatment step: Conduct diffusion heat treatment on the semi-solid composite material structure. The treatment temperature is 410 °C, the time is 40 min, and the cooling method is air cooling.

[0148] S50. Rolling step: Cold roll the composite material after diffusion heat treatment. After rolling, a titanium-aluminum-titanium laminated metal composite plate with a thickness of 0.2 mm is obtained. The rolling process is cold rolling, the rolling force is 515 MPa, the rolling speed is 1.5 m / min, the rolling deformation per pass is 20%, and the thickness changes during the rolling process are 0.48 mm, 0.384 mm, 0.308 mm, 0.244 mm, and 0.2 mm in sequence.

[0149] Performance testing

[0150] 1. Use a field emission scanning electron microscope (FE-SEM) to test the average thickness of the titanium-aluminum transition layer. The specific test experiment is as follows:

[0151] Environmental conditions: Temperature 23 ± 2 °C, humidity: 50 ± 10%RH;

[0152] Test standard: TestStandard: ASTM B748-90 (Reapproved 021).

[0153] Test conditions: First, inlay, grind, and polish the sample, then coat the cross-section with Pt for 25 s, and put it into the sample chamber of the scanning electron microscope according to the standard operation process to magnify and observe the test position and measure the thickness.

[0154] Test results: See Figure 6a and Figure 6b In this embodiment, the average thickness of the first interface transition layer in the titanium-aluminum-titanium laminated composite metal plate is 5.8 μm, and the average thickness of the second interface transition layer is about 4.5 μm.

[0155] The test was carried out according to the peeling method in GJB446-1988. The peeling strength is the interfacial bonding force of this embodiment. The tensile strength and yield strength were tested according to GB / T228.1-2010. The resistivity was tested according to GB / T 351-2019 "Measurement Method of Resistivity of Metallic Materials". The potentiodynamic polarization test was carried out using an electrochemical workstation to obtain the corrosion current density. The performance of the titanium-aluminum-titanium laminated composite metal plate described in Example 2 above was detected, as shown in Table 7 below.

[0156] Table 7: Performance test results of the titanium-aluminum-titanium laminated composite metal plate of Example 2

[0157]

[0158] Comparative Example 1:

[0159] On the basis of Example 1 above, the influence of omitting S40 and the diffusion heat treatment step on the performance of the titanium-aluminum-titanium laminated composite metal plate was further explored, and other conditions were kept the same as those in Example 1.

[0160] Performance test

[0161] 1. The average thickness of the titanium-aluminum transition layer was tested using a field emission scanning electron microscope (FE-SEM). The specific test experiment is as follows:

[0162] Environmental conditions: temperature 23±2°C, humidity: 50±10%RH;

[0163] Test standard: TestStandard: ASTMB748-90 (Reapproved021).

[0164] Test conditions: First, the sample was embedded, ground, and polished, then the cross-section was plated with Pt for 25 s, and it was placed in the sample chamber of the scanning electron microscope according to the standard operation procedure to magnify and observe the test position and measure the thickness.

[0165] Test results: See Figure 7a and Figure 7b , the average thickness of the first interface transition layer in the titanium-aluminum-titanium laminated composite metal plate of this embodiment is 1.0 μm, and the average thickness of the second interface transition layer is about 1.2 μm.

[0166] The test was carried out according to the peeling method in GJB446-1988. The peeling strength is the interfacial bonding force of this embodiment. The tensile strength and yield strength were tested according to GB / T228.1-2010. The resistivity was tested according to GB / T 351-2019 "Measurement Method of Resistivity of Metallic Materials". The potentiodynamic polarization test was carried out using an electrochemical workstation to obtain the corrosion current density. The performance of the titanium-aluminum-titanium laminated composite metal plate described in Comparative Example 1 above was detected, as shown in Table 8 below.

[0167] Table 8: Performance test results of the titanium-aluminum-titanium laminated composite metal plate of Comparative Example 1

[0168]

[0169] As can be seen from Table 8, after omitting S40 and the diffusion heat treatment step, the interfacial bonding strength, tensile strength, and yield strength of the finally obtained titanium-aluminum-titanium laminated metal composite plate are poor and cannot meet the requirements.

[0170] If the diffusion heat treatment step is omitted, the interface relies only on physical bonding, and the bonding strength is weak, making it easy to separate when stressed. In addition, the residual stress generated during the preparation of the composite plate cannot be eliminated by heat treatment, resulting in cracks or deformation in the material when stressed, thereby reducing its strength and yield strength. At the same time, a stable reaction layer cannot be formed at the interface, making it difficult to enhance the bonding strength. The diffusion heat treatment can also refine the grain structure and optimize the mechanical properties of the material; if this step is skipped, the grain structure cannot be improved, and the tensile strength and yield strength of the material will be difficult to meet the requirements.

[0171] Comparative Example 2:

[0172] This comparative example further explores the influence of omitting S20, the thinning treatment step, on the performance of the titanium-aluminum-titanium laminated composite metal plate.

[0173] A processing method for a titanium-aluminum-titanium laminated metal composite plate, comprising:

[0174] S10, the material preparation step: selecting solid titanium raw materials and selecting aluminum raw materials; wherein, the solid titanium raw materials are TA1 titanium alloy, and the aluminum raw materials are 6063 aluminum alloy; the thickness of the solid titanium raw materials is 0.1 mm, and the solid titanium raw materials are in the annealed state; the aluminum raw materials have good fluidity in the molten state.

[0175] S210, annealing the solid titanium sheet, the annealing temperature is 520 °C, the time is 30 min, and after annealing, air cooling is used for cooling;

[0176] S220, roughening the surface of the annealed solid titanium sheet to ensure its surface is clean and free of impurities. The roughening treatment is carried out by means of roughening with a titanium roughening machine, sandblasting, shot peening, electric spark or laser. After roughening, the surface roughness Ra of the solid titanium sheet is 4; after the roughening treatment is completed, the surface of the solid titanium sheet is cleaned by ultrasonic cleaning. After cleaning, the surface of the solid titanium sheet is dried by air drying or in a drying oven to ensure that the metal surface is clean and free of impurities and water stains;

[0177] S30. Pouring step: First, preheat two solid titanium sheets to 600 °C and fix them separately at a spacing of 0.18 mm. Then, melt the aluminum raw material, keep it at 680 °C for heat preservation, let it stand and skim the slag to ensure the quality of the molten aluminum. Finally, pour the molten aluminum between the two solid titanium sheets and let it solidify to obtain a semi-solid composite material structure.

[0178] S40. Diffusion heat treatment step: Conduct diffusion heat treatment on the semi-solid composite material structure. The treatment temperature is 410 °C, the time is 40 min, and the cooling method is air cooling.

[0179] S50. Rolling step: Cold roll the composite material after diffusion heat treatment. After rolling, the rolling process is cold rolling, the rolling force is 515 MPa, the rolling speed is 1.5 m / min, and the rolling deformation per pass is 20%. Obtain a titanium-aluminum-titanium laminated metal composite plate with a thickness of 0.25 mm.

[0180] As can be seen from the above, when omitting S20, the thinning treatment step, the finally obtained titanium-aluminum-titanium laminated metal composite plate is 0.25 mm, which cannot meet the requirement of controlling the total thickness of the titanium-aluminum-titanium laminated metal composite plate to be less than 0.2 mm.

[0181] The above embodiments are only the preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention belong to the scope of protection required by the present invention.

Claims

1. A titanium-aluminum-titanium layered metal composite plate, comprising a metal composite plate body; characterized in that: The metal composite plate body comprises a first titanium metal layer, an aluminum metal layer and a second titanium metal layer which are composited in sequence from top to bottom; wherein, A first interface transition layer is formed between the first titanium metal layer and the aluminum metal layer, and a second interface transition layer is formed between the second titanium metal layer and the aluminum metal layer; The thickness of the metal composite plate body is 0.05-0.2 mm, the thickness of the first interface transition layer is 3-6 μm, and the thickness of the second interface transition layer is 3-6 μm; The metal composite plate body is formed by pouring molten aluminum between two solid titanium sheets that have been thinned, and then undergoing diffusion heat treatment and rolling after solidification. The casting steps include first preheating two solid titanium sheets to 590-610°C and fixing them at a preset distance; then melting the aluminum raw material, keeping it warm at 670-690°C, letting it stand and slagging to ensure the quality of the aluminum melt; finally, pouring the molten aluminum between the two solid titanium sheets and solidifying them to obtain a semi-solid composite material structure; The diffusion heat treatment step includes performing diffusion heat treatment on the semi-solid composite material structure; the treatment temperature is 350-420° C., the time is 30-130 minutes, and the cooling method is air cooling; The rolling step includes cold rolling the composite material after diffusion heat treatment, and after rolling is completed, a titanium-aluminum-titanium layered metal composite plate is obtained; the rolling process is cold rolling, the rolling force is above 500MPa, the rolling speed is 1-2m / min, and the deformation of each rolling pass does not exceed 20%.

2. The titanium-aluminum-titanium layered metal composite plate according to claim 1, characterized in that: The thickness of the metal composite plate body is 0.1-0.2 mm; the thickness of the first interface transition layer is 4.5-6 μm, and the thickness of the second interface transition layer is 4.5-6 μm.

3. The titanium-aluminum-titanium layered metal composite plate according to claim 1, characterized in that: The thickness ratio of the first titanium metal layer to the aluminum metal layer is 1:(1-1.5); the thickness of the first titanium metal layer is the same as that of the second titanium metal layer.

4. The titanium-aluminum-titanium layered metal composite plate according to claim 1, characterized in that: The thickness of the first titanium metal layer is 0.015-0.06 mm, the thickness of the aluminum metal layer is 0.02-0.04 mm, and the thickness of the second titanium metal layer is 0.015-0.06 mm.

5. The titanium-aluminum-titanium layered metal composite plate according to claim 1, characterized in that: The bending strength of the metal composite plate body is greater than or equal to 140 MPa, the electrical resistance is less than or equal to 10.5 μΩ·cm, and the corrosion current density is less than or equal to 0.85 μA / cm2.

6. A method for processing a titanium-aluminum-titanium layered metal composite plate according to any one of claims 1 to 5, characterized in that: include: S10, material preparation step: selecting solid titanium raw material and selecting aluminum raw material; S20, a thinning treatment step: thinning the solid titanium raw material to 0.015-0.06 mm by a rolling process to obtain at least two solid titanium sheets; S30, casting step: first, preheating two solid titanium sheets to 590-610°C, and fixing them at a preset distance; then melting the aluminum raw material, and keeping it at 670-690°C, standing it and slagging it to ensure the quality of the aluminum melt; finally, pouring the molten aluminum between the two solid titanium sheets, and solidifying it to obtain a semi-solid composite material structure; controlling the distance between the two solid titanium sheets to be 0.09-0.36mm; S40, diffusion heat treatment step: performing diffusion heat treatment on the semi-solid composite material structure; the treatment temperature is 350-420° C., the time is 30-130 min, and the cooling method is air cooling; S50, rolling step: cold rolling the composite material after the diffusion heat treatment, after rolling, a titanium-aluminum-titanium layered metal composite plate with a thickness of 0.05-0.2 mm is obtained; the rolling process is cold rolling, the rolling force is above 500 MPa, the rolling speed is 1-2 m / min, and the deformation of each rolling pass does not exceed 20%.

7. The method for processing the titanium-aluminum-titanium layered metal composite plate according to claim 6, characterized in that: S10, in the material preparation step, the thickness of the solid titanium raw material does not exceed 0.1 mm, and the solid titanium raw material is in an annealed state; the aluminum raw material has good fluidity in a molten state.

8. The method for processing the titanium-aluminum-titanium layered metal composite plate according to claim 6, characterized in that: There is also a step S210 between step S20 and step S30. Step S210 includes: annealing the solid titanium sheet after the thinning process, the annealing temperature is 490-520° C., the time is 30-50 minutes, and air cooling is adopted after the annealing is completed.

9. The method for processing the titanium-aluminum-titanium layered metal composite plate according to claim 8, characterized in that: A step S220 is also included between step S210 and step S30. Step S220 includes: roughening the surface of the annealed solid titanium sheet to ensure that the surface is clean and free of impurities.

10. The method for processing the titanium-aluminum-titanium layered metal composite plate according to claim 9, characterized in that: In step S220, the texturing treatment is performed by a titanium texturing machine, sandblasting, shot peening, electric spark or laser texturing. After the texturing is completed, the surface roughness Ra of the solid titanium sheet is 3-5.

11. The method for processing the titanium-aluminum-titanium layered metal composite plate according to claim 10, characterized in that: After the texturing treatment is completed, the surface of the solid titanium sheet is cleaned by ultrasonic cleaning. After cleaning, the surface of the solid titanium sheet is dried by air drying or drying oven to ensure that the metal surface is clean and free of impurities and water stains.

12. The method for processing the titanium-aluminum-titanium layered metal composite plate according to claim 6, characterized in that: S50, in the rolling step, When the thickness of the titanium-aluminum-titanium layered metal composite plate is controlled to be 0.05 mm, the thickness changes during the rolling process are 0.12 mm, 0.096 mm, 0.077 mm, 0.061 mm, and 0.05 mm; When the thickness of the titanium-aluminum-titanium layered metal composite plate is controlled to be 0.1 mm, the thickness changes during the rolling process are 0.24 mm, 0.192 mm, 0.154 mm, 0.122 mm, and 0.1 mm; When the thickness of the titanium-aluminum-titanium layered metal composite plate is controlled to be 0.2 mm, the thickness changes during the rolling process are 0.48 mm, 0.384 mm, 0.308 mm, 0.244 mm, and 0.2 mm, respectively.

13. A bipolar plate, characterized in that: The titanium-aluminum-titanium layered metal composite plate is manufactured according to any one of claims 1 to 5.

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