High-performance copper-aluminum interfacial eutectic composite material and preparation method thereof

Abstract

The application discloses a high-performance copper-aluminum interface eutectic composite material, which comprises an aluminum plate and copper plates, the aluminum plate is a base layer, the upper and lower copper plates are cover layers, and a eutectic layer is formed between the aluminum plate and the upper and lower copper plates; the aluminum plate comprises the following components in percentage by weight: Si: 0.04-0.25%, Fe: 0.1-0.3%, Ti: less than 0.15%, and the rest is Al and inevitable impurities; the copper plate comprises the following components in percentage by weight: Pb: less than 0.03%, Fe: less than 0.1%, and the rest is Cu and inevitable impurities; and a preparation method of the high-performance copper-aluminum interface eutectic composite material is provided. The application has higher shearing strength and peeling strength; metallurgical bonding can be realized between the composite metals, a eutectic layer is formed, and the bonding strength of the material can be met; and compared with the existing composite material production mode, the preparation method is simpler, more economical and more efficient.

Description

Technical Field

[0001] This invention relates to the field of bimetallic composite materials, specifically to a copper-aluminum interface eutectic composite material with good tensile strength, high peel strength, and excellent electrical conductivity, and its preparation method. Background Technology

[0002] Aluminum composite materials are lightweight, high-performance layered composite conductor materials with an outer layer of copper and an inner layer of aluminum or aluminum alloy. They combine the excellent conductivity of copper with the outstanding lightweight properties and cost advantages of aluminum.

[0003] The main preparation methods of copper-aluminum composite plates can be divided into three types according to the basic state of the matrix during bonding: solid-solid composite method, liquid-liquid composite method, and solid-liquid composite method.

[0004] Solid-solid composites are basically of two types: rolling composites and explosive composites. Rolling composites require surface treatment of both metals, followed by mechanical bonding under rolling force, and then diffusion annealing to achieve a metallurgical bond. This method involves many steps, low efficiency, and high energy consumption. Explosive composites have significant limitations on the thickness of the composite plates produced and require specific explosion sites, resulting in high noise and safety risks. Liquid-liquid composites use twin-crystal continuous casting to facilitate metallurgical bonding at the copper-aluminum interface, but the copper-aluminum interface layer is often too thick, the equipment structure is complex, investment is high, product dimensions are relatively limited, and the process is complex and lacks stability. Solid-liquid composites can shorten the manufacturing process, save energy, and reduce costs; however, currently, solid-liquid composites cannot produce copper-aluminum composite plates with good interfacial bonding performance, and the eutectic layer thickness of the produced composite plates is unsatisfactory.

[0005] Eutectic composites can optimize mechanical properties by adjusting the microstructure and size through changes in component ratios and solidification conditions. They can also improve strength, toughness, wear resistance, and corrosion resistance by utilizing the synergistic effect between different components. Furthermore, the concept of high-entropy alloys can be introduced to increase the diversity and complexity of components, thereby achieving ultra-high strength and plasticity.

[0006] Therefore, there is a need to provide a method for preparing copper-aluminum composite materials that can generate a eutectic layer, so as to ensure that the copper-aluminum composite materials have good interfacial bonding and excellent performance. Summary of the Invention

[0007] To overcome the shortcomings of existing bimetallic composite plates, such as low composite strength, poor product performance, high production cost, and low production efficiency, this invention provides a high-performance copper-aluminum interface eutectic composite plate with high shear strength and peel strength, and also provides a simple, economical, and efficient method for preparing copper-aluminum eutectic composite materials.

[0008] The technical solution adopted by this invention to solve its technical problem is:

[0009] A high-performance copper-aluminum interfacial eutectic composite material includes an aluminum plate and a copper plate, wherein the aluminum plate is the base layer, the upper and lower copper plates are the cladding layers, and a eutectic layer is formed between the aluminum plate and the upper and lower copper plates. The composition of the aluminum plate by weight percentage is as follows: Si: 0.04~0.25%, Fe: 0.1~0.3%, Ti<0.15%, with the remainder being Al and unavoidable impurities. The composition of the copper plate by weight percentage is as follows: Pb<0.03%, Fe<0.1%, with the remainder being Cu and unavoidable impurities.

[0010] Furthermore, the aluminum plate is 1050, 1060, 1100, 8011 or 3003 aluminum, with an aluminum content greater than 98%, and the thickness ranges from 6 to 16 mm; the copper plate is T2 copper or brass, and the thickness ranges from 5% to 35% of the composite plate thickness.

[0011] Preferably, the thickness ratio of the copper plate to the aluminum plate is 1:(2~20).

[0012] Furthermore, the composition of the eutectic layer compound includes Al2Cu and Al4Cu9, the interface layer thickness of the eutectic layer is 300-500 nm, and the crystal phase composite rate is >40%.

[0013] Preferably, the eutectic composite material has a conventional shear strength of 75~80MPa, a conventional peel strength of 140~170KPa, a tensile strength of >202MPa at room temperature, a shear strength of 80~85MPa after 24 hours at 300℃, a peel strength of 80~85KPa after 24 hours at 300℃, and an elongation after fracture of >15%.

[0014] A method for preparing a high-performance copper-aluminum interfacial eutectic composite material includes copper plate surface pretreatment, copper plate preheating, solid-liquid composite casting and rolling, composite slab homogenization annealing, cold rolling, and secondary annealing, comprising the following steps:

[0015] 1) Copper plate surface pretreatment: The copper plate is first subjected to high-pressure rinsing to quickly remove solid impurities from the surface; then it is subjected to low-pressure rinsing with an alkaline degreasing solution at 50℃~70℃ to remove grease from the surface; the oxide layer on the surface of the copper plate is polished off using a steel brush, which can improve the surface roughness, increase the copper-aluminum composite area, and thus enhance the adhesion of the composite material; finally, the copper plate is dried for later use.

[0016] 2) Copper plate preheating: The pretreated copper plate is fixed and fed into the feeding equipment, and heated to 150℃~220℃ in an oxygen-free environment to increase the atomic thermal activation energy, so that the atoms can obtain enough energy in a short time under high temperature to migrate and form a thicker eutectic layer, thereby effectively improving the bonding strength of the copper-aluminum composite interface.

[0017] 3) Solid-liquid composite casting and rolling: Aluminum ingots are heated to 660℃~710℃ to obtain molten aluminum. Inert gas is then introduced near the rolls to fill the casting environment, creating an oxygen-free environment. This prevents the copper plate and aluminum from forming an oxide layer due to direct exposure to air during the composite process, which would hinder the formation of an ideal eutectic layer and negatively impact the material's peel strength. Simultaneously, the outer surface temperature of the rolls is heated to 85~95℃. Cooling liquid is introduced into the rolls to increase the cooling rate of the casting and rolling process, resulting in smaller grains and improved material strength. The casting and rolling equipment is then started, allowing the molten aluminum and the treated copper plate to contact in the oxygen-free environment, achieving continuous solid-liquid composite oxygen-free casting and rolling. Finally, a copper-aluminum composite slab is obtained, with a 100% composite rate after solid-liquid composite casting and rolling.

[0018] 4) Homogenization annealing of composite slab: The obtained copper-aluminum composite slab is placed in an annealing furnace for homogenization annealing to reduce intragranular segregation on both sides of the copper-aluminum alloy, remove residual stress, and improve alloy performance.

[0019] 5) Cold rolling: The annealed composite slab is rolled a second time. The rolling equipment is adjusted to obtain the required plate thickness and width. The final plate thickness after the second rolling is 0.2~16mm, of which the copper plate thickness is 5%~35% of the overall composite plate thickness, and the plate width is 600~1200mm.

[0020] 6) Secondary annealing: Finally, the cold-rolled copper-aluminum composite plate is subjected to secondary annealing to refine the grains, adjust the microstructure, and eliminate microstructural defects. Since there is a certain internal stress during the rolling process, it will lead to a decrease in the strength of the composite material. Therefore, the annealing process can reduce residual stress, stabilize dimensions, reduce deformation and cracking tendency, and ensure that the product has good comprehensive mechanical properties and good metallurgical bonding.

[0021] Furthermore, in the homogenization annealing process of step 4), the heating temperature is 430℃~510℃ and the annealing time is 4~5h.

[0022] Furthermore, in the secondary annealing process of step 6), the heating temperature is 300℃~350℃, and the temperature is cooled to below 80℃ in the annealing furnace.

[0023] Furthermore, in step 3), the inert gas is nitrogen.

[0024] Preferably, in step 1), the rinsing solution is an alkaline degreasing solution at 50℃~70℃.

[0025] In the solid-liquid composite casting and rolling process of step 3), the rolling speed of the rolls is 600~1300 mm / min.

[0026] In step 3), the temperature of the coolant is 20℃~30℃, and the cooling rate is 300~1000℃ / s.

[0027] The beneficial effects of this invention are mainly reflected in the following aspects: the high-performance copper-aluminum interface eutectic composite plate has high shear strength and peel strength; it can achieve metallurgical bonding between composite metals to form a eutectic layer, which can meet the bonding strength of the materials; at the same time, compared with the existing composite material production methods, the preparation method provided by this invention is simpler, more economical and more efficient; and the high-performance copper-aluminum interface eutectic composite material of this invention has broad application prospects. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the copper-aluminum eutectic composite material in this invention;

[0029] Figure 2 This is a schematic diagram of the thickness of the interfacial eutectic layer of the copper-aluminum eutectic composite material in this invention;

[0030] Figure 3 This refers to the eutectic layer phase composition of the copper-aluminum eutectic composite material in this invention. Detailed Implementation

[0031] The present invention will now be further described with reference to the accompanying drawings.

[0032] Reference Figures 1-3 A high-performance copper-aluminum interface eutectic composite material includes an aluminum plate 1 and a copper plate 2. The aluminum plate 1 is the base layer, and the upper and lower copper plates 2 are the cladding layers. A eutectic layer 3 is formed between the aluminum plate and the upper and lower copper plates. The composition of the aluminum plate 1 by weight percentage is as follows: Si: 0.04~0.25%, Fe: 0.1~0.3%, Ti<0.15%, with the remainder being Al and unavoidable impurities. The composition of the copper plate 2 by weight percentage is as follows: Pb<0.03%, Fe<0.1%, with the remainder being Cu and unavoidable impurities.

[0033] Furthermore, the aluminum plate 1 is made of 1050, 1060, 1100, 8011 or 3003 aluminum, with an aluminum content greater than 98%, and a thickness ranging from 6 to 16 mm; the copper plate 2 is made of T2 copper or brass, and a thickness ranging from 5% to 35% of the composite plate thickness.

[0034] Preferably, the thickness ratio of the copper plate 2 to the aluminum plate 1 is 1:(2~20).

[0035] Furthermore, the composition of the eutectic layer 3 compound includes Al2Cu and Al4Cu9, the interface layer thickness of the eutectic layer is 300-500nm, and the crystal phase test composite rate is >40%.

[0036] Preferably, the eutectic composite material has a conventional shear strength of 75~80MPa, a conventional peel strength of 140~170KPa, a tensile strength of >202MPa at room temperature, a shear strength of 80~85MPa after 24 hours at 300℃, a peel strength of 80~85KPa after 24 hours at 300℃, and an elongation after fracture of >15%.

[0037] A method for preparing a high-performance copper-aluminum interfacial eutectic composite material includes copper plate surface pretreatment, copper plate preheating, solid-liquid composite casting and rolling, composite slab homogenization annealing, cold rolling, and secondary annealing, comprising the following steps:

[0038] 1) Copper plate surface pretreatment: The copper plate is first subjected to high-pressure rinsing to quickly remove solid impurities from the surface; then it is subjected to low-pressure rinsing with an alkaline degreasing solution at 50℃~70℃ to remove grease from the surface; the oxide layer on the surface of the copper plate is polished off using a steel brush, which can improve the surface roughness, increase the copper-aluminum composite area, and thus enhance the adhesion of the composite material; finally, the copper plate is dried for later use.

[0039] In step 1), the rinsing solution is an alkaline degreasing solution at 50℃~70℃.

[0040] 2) Copper plate preheating: The pretreated copper plate is fixed and fed into the feeding equipment, and heated to 150℃~220℃ in an oxygen-free environment to increase the atomic thermal activation energy, so that the atoms can obtain enough energy in a short time under high temperature to migrate and form a thicker eutectic layer, thereby effectively improving the bonding strength of the copper-aluminum composite interface.

[0041] 3) Solid-liquid composite casting and rolling: Aluminum ingots are heated to 660℃~710℃ to obtain molten aluminum. Inert gas is then introduced near the rolls to fill the casting environment, creating an oxygen-free environment. This prevents the copper plate and aluminum from forming an oxide layer due to direct exposure to air during the composite process, which would hinder the formation of an ideal eutectic layer and negatively impact the material's peel strength. Simultaneously, the outer surface temperature of the rolls is heated to 85~95℃. Cooling liquid is introduced into the rolls to increase the cooling rate of the casting and rolling process, resulting in smaller grains and improved material strength. The casting and rolling equipment is then started, allowing the molten aluminum and the treated copper plate to contact in the oxygen-free environment, achieving continuous solid-liquid composite oxygen-free casting and rolling. Finally, a copper-aluminum composite slab is obtained, with a 100% composite rate after solid-liquid composite casting and rolling.

[0042] In step 3), the inert gas is nitrogen.

[0043] In the solid-liquid composite casting and rolling process of step 3), the rolling speed of the rolls is 600~1300 mm / min.

[0044] In step 3), the temperature of the coolant is 20℃~30℃, and the cooling rate is 300~1000℃ / s.

[0045] 4) Homogenization annealing of composite slab: The obtained copper-aluminum composite slab is placed in an annealing furnace for homogenization annealing to reduce intragranular segregation on both sides of the copper-aluminum alloy, remove residual stress, and improve alloy performance.

[0046] In the homogenization annealing process of step 4), the heating temperature is 430℃~510℃ and the annealing time is 4~5h.

[0047] 5) Cold rolling: The annealed composite slab is rolled a second time. The rolling equipment is adjusted to obtain the required plate thickness and width. The final plate thickness after the second rolling is 0.2~16mm, of which the copper plate thickness is 5%~35% of the overall composite plate thickness, and the plate width is 600~1200mm.

[0048] 6) Secondary annealing: Finally, the cold-rolled copper-aluminum composite plate is subjected to secondary annealing to refine the grains, adjust the microstructure, and eliminate microstructural defects. Since there is a certain internal stress during the rolling process, it will lead to a decrease in the strength of the composite material. Therefore, the annealing process can reduce residual stress, stabilize dimensions, reduce deformation and cracking tendency, and ensure that the product has good comprehensive mechanical properties and good metallurgical bonding.

[0049] In the secondary annealing process of step 6), the heating temperature is 300℃~350℃, and the temperature is cooled to below 80℃ in the annealing furnace.

[0050] The preparation method of the high-performance copper-aluminum interface eutectic composite material in this embodiment includes the following steps:

[0051] 1) Copper plate surface pretreatment: The copper plate is first rinsed under high pressure to remove solid impurities such as particles from the surface of the copper plate; then it is rinsed under low pressure with an alkaline degreasing solution at 50℃-70℃ for degreasing treatment; the oxide layer on the surface of the copper plate is polished off using a steel brush; finally, the copper plate is dried for later use.

[0052] 2) Copper plate preheating: The processed copper plate is fixedly fed into the feeding equipment and heated to 150℃~220℃ in an oxygen-free environment;

[0053] 3) Solid-liquid composite casting and rolling: Aluminum ingots are heated to 660℃~710℃ to obtain molten aluminum liquid; then, inert gas is introduced near the rolls to fill the casting and rolling environment, while the outer surface temperature of the rolls is heated to 90℃; coolant is introduced into the rolls to ensure that the aluminum liquid can be rapidly cooled and formed during the casting and rolling process; the casting and rolling equipment is started, and the molten aluminum liquid and the treated copper plate are brought into contact in an oxygen-free environment to achieve solid-liquid composite oxygen-free continuous casting and rolling, finally obtaining a copper-aluminum composite slab. The composite rate after solid-liquid composite casting and rolling is 100%.

[0054] like Figure 2 As shown, the average thickness of the eutectic layer interface is 380.4 mm. Figure 3 The phase composition of the eutectic layer shown includes Al2Cu and Al4Cu9, with a crystal phase composite rate >40%.

[0055] 4) Homogenization annealing of composite slab: The obtained copper-aluminum composite slab is placed in an annealing furnace, heated to a certain temperature, and held for 4-5 hours;

[0056] 5) Cold rolling: The annealed composite slab is rolled a second time. The rolling equipment is adjusted to obtain the required plate thickness and width. The final plate thickness after the second rolling is 0.2~16mm, of which the copper plate thickness is 5%~35% of the overall composite plate thickness, and the plate width is 600~1200mm.

[0057] 6) Secondary annealing: Finally, the cold-rolled copper-aluminum composite plate is heated to 300℃~350℃ and then cooled to below 80℃ in an annealing furnace to refine the grains, adjust the structure, eliminate structural defects, and ensure that the product has good comprehensive mechanical properties and good metallurgical bonding.

[0058] The final copper-aluminum composite strip has a conventional peel strength of 148 N / mm and a peel strength of 81 N / mm after heating at 300℃ for 24 hours, which far exceeds the national standard of 12 N / mm.

[0059] The embodiments described in this specification are merely examples of implementations of the inventive concept and are for illustrative purposes only. The scope of protection of this invention should not be considered limited to the specific forms described in these embodiments; rather, it extends to equivalent technical means conceived by those skilled in the art based on the inventive concept.

Claims

1. A high-performance copper-aluminum interfacial eutectic composite material, comprising an aluminum plate and upper and lower copper plates, wherein the aluminum plate is a base layer and the upper and lower copper plates are cladding layers, characterized in that, A eutectic layer is formed between the aluminum plate and the upper and lower copper plates. The composition of the aluminum plate by weight percentage is as follows: Si: 0.04~0.25%, Fe: 0.1~0.3%, Ti<0.15%, with the remainder being Al and unavoidable impurities. The composition of the copper plate by weight percentage is as follows: Pb<0.03%, Fe<0.1%, with the remainder being Cu and unavoidable impurities. The composition of the eutectic layer compound includes Al2Cu and Al4Cu9, and the thickness of the interface layer of the eutectic layer is 300-500 nm. The conventional shear strength of the eutectic composite material is 75-80 MPa, the conventional peel strength is 140-170 kPa, the tensile strength at room temperature is >202 MPa, the shear strength after 24 hours at 300℃ is 80-85 MPa, the peel strength after 24 hours at 300℃ is 80-85 kPa, and the elongation after fracture is >15%.

2. The high-performance copper-aluminum interface eutectic composite material as described in claim 1, characterized in that, The aluminum plate is made of 1050, 1060, 1100, 8011 or 3003 aluminum, with an aluminum content greater than 98%, and a thickness ranging from 6 to 16 mm; the copper plate is made of T2 copper or brass, and a thickness ranging from 5% to 35% of the composite plate thickness.

3. A high-performance copper-aluminum interface eutectic composite material as described in claim 1 or 2, characterized in that, The thickness ratio of the copper plate to the aluminum plate is 1:(2~20).

4. A method for preparing a high-performance copper-aluminum interfacial eutectic composite material as described in claim 1, characterized in that, The method includes the following steps: 1) Copper plate surface pretreatment: The copper plate is first rinsed under high pressure to quickly remove solid impurities from the surface of the copper plate; then it is rinsed under low pressure with an alkaline degreasing solution at 50℃~70℃ to remove grease from the surface of the copper plate; the oxide layer on the surface of the copper plate is polished off by a steel brush; finally, the copper plate is dried for later use. 2) Copper plate preheating: The pretreated copper plate is fixedly fed into the feeding equipment and heated to 150℃~220℃ in an oxygen-free environment to form a thicker eutectic layer; 3) Solid-liquid composite casting and rolling: Aluminum ingots are heated to 660℃~710℃ to obtain molten aluminum liquid; then, inert gas is introduced near the rolls to fill the casting and rolling environment, forming an oxygen-free environment; at the same time, the outer surface temperature of the rolls is heated to 85~95℃; coolant is introduced into the rolls to increase the cooling rate of the casting and rolling process, forming smaller grains; the casting and rolling equipment is started, and the molten aluminum liquid and the treated copper plate are brought into contact in the oxygen-free environment to achieve solid-liquid composite oxygen-free continuous casting and rolling, finally obtaining a copper-aluminum composite slab. The composite rate after solid-liquid composite casting and rolling is 100%. 4) Homogenization annealing of composite slab: The obtained copper-aluminum composite slab is placed in an annealing furnace for homogenization annealing; 5) Cold rolling: The annealed composite slab is rolled a second time. The rolling equipment is adjusted to obtain the required plate thickness and width. The final plate thickness after the second rolling is 0.2~16mm, of which the copper plate thickness is 5%~35% of the overall composite plate thickness, and the plate width is 600~1200mm. 6) Secondary annealing: Finally, the cold-rolled copper-aluminum composite plate is subjected to secondary annealing to refine the grains, adjust the microstructure, and eliminate microstructural defects.

5. The preparation method according to claim 4, characterized in that, In the homogenization annealing process of step 4), the heating temperature is 430℃~510℃ and the annealing time is 4~5h.

6. The preparation method according to claim 4 or 5, characterized in that, In the secondary annealing process of step 6), the heating temperature is 300℃~350℃, and the temperature is cooled to below 80℃ in the annealing furnace.

7. The preparation method according to claim 4 or 5, characterized in that, In step 3), the inert gas is nitrogen; in the solid-liquid composite casting and rolling, the rolling speed of the rolls is 600~1300mm / min; the temperature of the coolant is 20℃~30℃, and the cooling rate is 300~1000℃ / s.

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