High-strength and high-corrosion-resistance brazing aluminum alloy composite material for heat sink and preparation method thereof

Abstract

The application relates to a high-strength and high-corrosion-resistance brazing aluminum alloy composite material for a radiator and a preparation method thereof, which comprises a brazing layer, a core layer and a corrosion-resistant layer arranged in sequence, the core layer comprises the following element components with the percentage by weight: 0.3-0.7% of iron, 0.5-0.8% of copper, 1.4-1.8% of manganese, 0.1-0.15% of zirconium, <=0.05% of magnesium, <=0.05% of zinc, <=0.05% of titanium, and the balance of aluminum and inevitable impurities; the corrosion-resistant layer comprises the following element components with the percentage by weight: 0.5-1.0% of silicon, 0.2-0.3% of iron, 0-0.1% of copper, 1.4-1.8% of manganese, 4.0-5.0% of zinc, 0.01-0.03% of titanium, 0.07-0.12% of zirconium, and the balance of aluminum and inevitable impurities. The application has the effects of improving the strength and corrosion resistance of the brazing aluminum alloy.

Description

Technical Field

[0001] This application relates to the field of aluminum alloy materials, and in particular to a high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators and its preparation method. Background Technology

[0002] In recent years, the traditional radiator industry has faced enormous challenges. The market demands increasingly higher standards for materials, requiring improvements in both material strength and lifespan while reducing material thickness.

[0003] For example, the thickness of the aluminum alloy tubing used in radiators has decreased from the initial 0.28-0.3mm to 0.25-0.26mm, while the strength has increased from 150-160MPa to 190-200MPa. The material has also been changed from the traditional 3003 aluminum alloy to a reinforced 3003mod aluminum alloy. These products all use a three-layer composite structure in use: a brazed layer, a core layer, and an anti-corrosion layer. However, with the increase in market demand and the development trend of using high-strength and corrosion-resistant materials, it is necessary to further improve the performance of the tubing. Summary of the Invention

[0004] To improve the strength of composite materials, this application provides a high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators and its preparation method.

[0005] This application provides a high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators and its preparation method, using the following technical solution: In the first aspect, this application provides a high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators, which adopts the following technical solution: A high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators comprises a brazed layer, a core layer, and an anti-corrosion layer arranged sequentially. The core layer comprises the following elemental components by weight percentage: iron 0.3-0.7%, copper 0.5-0.8%, manganese 1.4-1.8%, zirconium 0.1-0.15%, magnesium ≤0.05%, zinc ≤0.05%, titanium ≤0.05%, with the balance being aluminum and unavoidable impurities. The anti-corrosion layer comprises the following elemental components by weight percentage: silicon 0.5-1.0%, iron 0.2-0.3%, copper 0-0.1%, manganese 1.4-1.8%, zinc 4.0-5.0%, titanium 0.01-0.03%, zirconium 0.07-0.12%, with the balance being aluminum and unavoidable impurities.

[0006] By adopting the above technical solution and controlling the content of each element in the core layer, the overall performance of the core layer can be effectively improved. Iron can enhance the overall hardness and strength of the core layer and also has a positive impact on the thermal stability of the alloy. Copper can strengthen the core layer, thereby further improving the tensile strength and fatigue resistance of the core material. Manganese can also enhance the strength of the core layer and has a positive impact on the plasticity of the prepared composite material. Zirconium can refine the grains, increase the recrystallization temperature, and also provide corrosion resistance. Furthermore, controlling the above elements within a certain ratio range can effectively improve the stability and overall performance of the core layer, resulting in a composite material with good strength and corrosion resistance. The anti-corrosion layer further enhances the corrosion resistance of the composite material. Simultaneously, the mass ratio of each element in the anti-corrosion layer is limited, thereby further improving the overall comprehensive performance and strength of the anti-corrosion layer. Silicon is also added to the anti-corrosion layer, which improves its fluidity and hardness, further enhancing its overall corrosion resistance. The addition of manganese gives the anti-corrosion layer good strength, while the addition of zinc reduces the electrode potential of the anti-corrosion layer. In actual use, the zinc-containing anti-corrosion layer and the copper-containing core layer form an in-situ cell due to the potential difference, with the anti-corrosion layer acting as the anode. By sacrificing the anode to protect the cathode, the core layer is prevented from corroding completely before the anti-corrosion layer is fully corroded, thus extending the overall service life of the composite material.

[0007] Preferably, the iron element in the anti-corrosion layer is derived from iron carbonyl, which is prepared by modification treatment. The modification treatment method for iron carbonyl includes the following steps: The modifier was dissolved in a solvent and ultrasonically treated to obtain a surfactant dispersion. Carbonyl iron powder was added to the surfactant dispersion and stirred at a constant temperature for a certain time. After washing and drying, pre-modified carbonyl iron was obtained. Polydimethylsiloxane was added to n-heptane and ultrasonically treated to obtain a mixture. Then, the pre-modified carbonyl iron was added to the mixture and stirred. After washing and drying, modified carbonyl iron was obtained.

[0008] By adopting the above technical solution, the addition of carbonyl iron as an iron element to the anti-corrosion layer can effectively improve the stability of the anti-corrosion layer. After modification with a modifier, the overall corrosion resistance of carbonyl iron can be further improved. At the same time, the surface energy of carbonyl iron particles can be reduced, so that the modified carbonyl iron is in a stable state. Meanwhile, the lipophilic groups of the modifier form a spatial barrier on the surface of carbonyl iron, reducing the phenomenon of particle re-aggregation. After treatment with polydimethylsiloxane, the amino groups on the surface of glycine-modified powder and the terminal hydroxyl groups of polydimethylsiloxane undergo a dehydration condensation reaction, so that polydimethylsiloxane can further coat the powder, thereby further improving the overall hydrophobicity and corrosion resistance of carbonyl iron. Therefore, the dispersion performance, stability performance and corrosion resistance of carbonyl iron after modification with the modifier are improved, thus improving the overall performance of the corrosion-resistant layer.

[0009] Preferably, the modifier includes any one of hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and glycine.

[0010] By adopting the above technical solutions, the above modifiers all contain hydrophobic groups. After modifying carbonyl iron with the above modifiers, the surface contact angle of carbonyl iron can be increased, thus playing a hydrophobic role and improving the dispersibility of carbonyl iron in the system. At the same time, the absolute impedance of carbonyl iron after modification with the modifier can be improved, and the corrosion potential of the powder shifts positively. Therefore, the modified carbonyl iron improves the overall corrosion resistance of the system, thereby improving the corrosion resistance and stability of the composite material.

[0011] Preferably, the mass ratio of the modifier, carbonyl iron, and polydimethylsiloxane is 1:(2.1-2.2):2.5.

[0012] By adopting the above technical solution, and optimizing the mass ratio between the modifier, carbonyl iron, and polydimethylsiloxane within the above range, the overall performance of the modified carbonyl iron can be further improved.

[0013] Preferably, the reaction time for preparing the pre-modified carbonyl iron is 1-2 hours.

[0014] Preferably, the reaction temperature during the preparation of the pre-modified carbonyl iron is 57-63℃.

[0015] By adopting the above technical solution, and optimizing the reaction time and temperature of the carbonyl iron modification treatment within the above range, the coating effect of the modifier on the carbonyl iron can be further improved, thereby further enhancing the performance of the modified carbonyl iron.

[0016] Preferably, the anti-corrosion layer further includes the following elements in weight percentage: magnesium 1.07-1.27% and scandium 0.04-0.06%.

[0017] By adopting the above technical solution, magnesium can effectively improve the overall corrosion resistance of the anti-corrosion aluminum alloy after adding magnesium. At the same time, magnesium has good mechanical properties, and its addition can improve the overall hardness and strength of the alloy, thereby further improving the strength of the anti-corrosion layer. The addition of scandium can effectively inhibit the precipitation of β phase, and while improving mechanical properties, it can also significantly improve the corrosion resistance of the alloy. The combination of the two can synergistically improve the strength and corrosion resistance of the system with zinc and zirconium. However, excessive magnesium can affect plasticity and corrosion resistance. It is preferable that the magnesium and scandium contents are within the above range. After combining with zinc and zirconium in the system, the oxygen adsorbed on the polarized anode surface forms a dense oxide film, which effectively prevents corrosion of the anti-corrosion layer and further improves the overall corrosion resistance and stability of the system.

[0018] Secondly, this application provides a method for preparing a high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators, using the following technical solution: A method for preparing a high-strength, high-corrosion-resistant brazed aluminum alloy for radiators includes the following steps: The materials for the brazing layer, core layer, and anti-corrosion layer are melted and cast separately according to the specified proportions. After melting and casting, each layer is milled. The milled brazing layer and anti-corrosion layer are then heated and hot-rolled to obtain the brazing prefabricated layer and anti-corrosion prefabricated layer, respectively. After cooling, the brazing prefabricated layer, core prefabricated layer, and anti-corrosion layer are stacked sequentially. The brazing prefabricated layer and anti-corrosion prefabricated layer are fixed to both sides of the core prefabricated layer by argon arc welding. The two ends are bound with steel strips to obtain a composite ingot. The composite ingot is rolled in a hot rolling mill and then rolled in a cold rolling mill to obtain a semi-finished coil. The edge cracks, burrs, and other parts of the semi-finished coil are removed. It is then rolled again in a cold finishing mill to obtain the coil of the final finished thickness. Subsequently, the coil is cleaned of oil and debris from the surface by a bending straightener. Finally, it is annealed in an annealing furnace, cooled, and cut to obtain the aluminum alloy composite material.

[0019] Preferably, the rolling process of the composite ingot in a hot rolling mill specifically includes the following steps: The middle part of the steel strips binding the two ends of the composite layer is cold-pressed, with the cold pressing direction from the middle to both ends. The rolling speed of the cold pressing is 20-30m / min, and the rolling is performed in 3-5 passes.

[0020] By adopting the above technical solution, cold pressing is performed before heating the composite layer. Through small reduction and slow rolling, the brazing layer, anti-corrosion layer and core layer can form a preliminary composite, which effectively reduces the phenomenon of misalignment and movement of the composite layer during formal hot rolling. At the same time, it allows the air in the gaps between the composite layers to be fully discharged, thereby reducing the occurrence of air not being completely discharged due to excessive rolling speed during formal hot rolling, which would eventually remain in the middle of the composite layer and form bubbles, resulting in defects in the finished product. This effectively improves the stability of the product.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. In this application, an aluminum alloy composite material is prepared by sequentially setting a brazing layer, a core layer, and an anti-corrosion layer. Simultaneously, the content of each element in the core layer is controlled, which effectively improves the overall hardness and strength of the core layer and also promotes the thermal stability of the alloy. Through the addition and proportioning of each component, the composite material can withstand more external forces and exhibits good corrosion resistance, thus improving the overall performance of the composite material. The proportion of each element in the anti-corrosion layer is limited, further enhancing the overall performance and strength of the anti-corrosion layer. In actual use, the zinc-containing anti-corrosion layer and the copper-containing core layer form an in-situ cell due to the potential difference, with the anti-corrosion layer acting as the anode. By sacrificing the anode to protect the cathode, the core layer is prevented from corroding completely before the anti-corrosion layer is fully corroded, thereby extending the overall service life of the composite material. 2. The iron element in the anti-corrosion layer comes from carbonyl iron. After the carbonyl iron is modified by a modifier, the modifier coats the surface of the carbonyl iron, thereby reducing the surface energy of the carbonyl iron particles and making the carbonyl iron in a stable state. In addition, the lipophilic groups of the modifier form a spatial flatness on the surface of the carbonyl iron, reducing the phenomenon of particle re-agglomeration and improving the absolute resistance. This causes the corrosion potential of the powder to shift positively. The dispersibility and corrosion resistance of the modified carbonyl iron are both improved. The modifier contains hydrophobic groups, which improves the contact angle of the modified carbonyl iron surface and gives it hydrophobic properties. Detailed Implementation

[0022] The present application will be further described in detail below with reference to the embodiments: Raw material description: All raw materials used in the examples are commercially available.

[0023] Example 1 Preparation of carbonyl iron: The modifier was dissolved in 200 mL of solvent and ultrasonically treated for 30 min to obtain a surfactant dispersion. Then, carbonyl iron powder was added to the surfactant dispersion and stirred at 57 °C for 1 h. After washing with deionized water and separation, the mixture was dried at 75 °C to obtain pre-modified carbonyl iron. Polydimethylsiloxane was added to 200 mL of n-heptane and ultrasonically treated at 60 °C for 20 min to obtain a mixture. Then, the pre-modified carbonyl iron was added to the mixture and stirred at 60 °C for 1.5 h. The mixture was washed three times alternately with deionized water and n-heptane and finally dried in an oven at 60 °C to obtain modified carbonyl iron. The modifier is glycine, the solvent is deionized water, and the mass ratio of the modifier, carbonyl iron and polydimethylsiloxane is 1:2.1:2.5.

[0024] The core layer consists of 0.3% iron, 0.5% copper, 1.4% manganese, and 0.1% zirconium, with the balance being aluminum and unavoidable impurities.

[0025] The anti-corrosion layer comprises 0.5% silicon, 0.01% iron, 1.4% manganese, 4% zinc, 0.01% titanium, 0.07% zirconium, 3.07% magnesium, 0.04% scandium, with the balance being aluminum and unavoidable impurities; among which, the iron element is derived from the modified carbonyl iron prepared above.

[0026] The brazing layer is made of 4343 aluminum alloy.

[0027] Preparation of brazed aluminum alloy composite materials: (1) The materials of the brazing layer, core layer and anti-corrosion layer are melted and cast separately according to the proportion. The melting temperature is 760℃ and the stirring is 20min. Then, the refining and degassing are carried out. The refining is carried out at 750℃ for 20min until the hydrogen content of the liquid aluminum water is ≤0.15ml / 100g Al. Then, the casting is carried out at 680℃, the casting speed is 40mm / min, the water pressure is 0.1MPa and the water temperature is 30℃. After the casting is completed, the gate of the prepared ingot is sawn off by 150mm. (2) The core layer, brazing layer and anti-corrosion layer are milled separately. The milling amount of each prefabricated layer is 7.5mm / each of the two large surfaces. After milling, the thickness of the core layer, brazing layer and anti-corrosion layer is 385±2mm. (3) The brazing layer and the anti-corrosion layer after milling are heated separately at a temperature of 520℃ and a holding time of 10h; then the heated brazing layer and the anti-corrosion layer are hot rolled to obtain the brazing prefabricated layer and the anti-corrosion prefabricated layer. The brazing prefabricated layer is rolled to 52±2mm and the anti-corrosion prefabricated layer is rolled to 70±2mm. Then, they are cut according to the preparation requirements, placed and naturally cooled. (4) Grind and clean the two large surfaces of the core layer, then stack the brazed prefabricated layer, the anti-corrosion prefabricated layer and the milled core prefabricated layer in sequence, fix the brazed prefabricated layer and the anti-corrosion prefabricated layer on both sides of the core prefabricated layer by argon arc welding, and tie the two ends with steel strips to obtain a composite ingot. (5) The composite ingot is cold-pressed in a hot rolling mill. The middle part of the steel strip at both ends of the composite ingot is cold-pressed from the middle to both ends. The rolling speed of cold pressing is 20m / min, and the rolling speed is adjusted downward by 0.5mm per pass. The rolling is performed in 3 passes. (6) The treated composite ingot is heated to 520℃ and held for 10 hours. Then, the composite layer is rolled into a billet with a thickness of 6.5±0.3mm by a hot rolling mill. The billet is then rolled in a cold rolling mill in passes of 6.5-4.0-2.6-1.6-1.0mm to obtain a semi-finished coil.

[0028] (7) The semi-finished coil is cut off at the edge with cracks and burrs by a rewinding and trimming machine. The trimming width of each side is 50mm. After trimming, the semi-finished coil is rolled in a cold finishing mill in passes of 1.0-0.75-0.58-0.45-0.36-0.28-0.22mm to obtain the coil with the final finished thickness. (8) Use a bending straightening machine to clean the oil stains, aluminum shavings and other impurities on the surface of the coil and optimize the overall pattern. The cleaning water temperature is 80℃ and the cleaning speed is 50m / min. (9) The cleaned roll material is annealed to H24 state in an annealing furnace. Under nitrogen protection, the temperature of the roll material is controlled at 250℃ and held for 4 hours. After being taken out of the furnace, it is naturally cooled and cut to complete the preparation.

[0029] Example 2 Preparation of carbonyl iron: The modifier was dissolved in 200 mL of solvent and ultrasonically treated for 30 min to obtain a surfactant dispersion. Then, carbonyl iron powder was added to the surfactant dispersion and stirred at 63 °C for 2 h. Finally, it was washed with deionized water, separated, and dried at 75 °C to obtain pre-modified carbonyl iron. Polydimethylsiloxane was added to 200 mL of n-heptane and ultrasonically treated at 60 °C for 20 min to obtain a mixture. Then, the pre-modified carbonyl iron was added to the mixture and stirred at 60 °C for 1.5 h. It was washed three times alternately with deionized water and n-heptane and finally dried in an oven at 60 °C to obtain modified carbonyl iron. The modifier is glycine, the solvent is deionized water, and the mass ratio of the modifier, carbonyl iron, and polydimethylsiloxane is 1:2.2:2.5.

[0030] The core layer consists of 0.7% iron, 0.8% copper, 1.8% manganese, 0.15% zirconium, 0.05% magnesium, 0.05% zinc, 0.05% titanium, with the balance being aluminum and unavoidable impurities.

[0031] The anti-corrosion layer comprises 1.0% silicon, 0.3% iron, 0.1% copper, 1.8% manganese, 5% zinc, 0.03% titanium, 0.12% zirconium, 3.27% magnesium, 0.06% scandium, with the balance being aluminum and unavoidable impurities; wherein the iron element is derived from the modified carbonyl iron prepared above.

[0032] The brazing layer is made of 4045 aluminum alloy.

[0033] Preparation of brazed aluminum alloy composite materials: (1) The materials of the brazing layer, core layer and anti-corrosion layer are melted and cast separately according to the proportion. The melting temperature is 780℃ and the stirring is 30min. Then, the refining and degassing are carried out. The refining is carried out at 760℃ for 30min until the hydrogen content of the liquid aluminum water is ≤0.15ml / 100g Al. Then, the casting is carried out at 710℃, the casting speed is 60mm / min, the water pressure is 0.2MPa and the water temperature is 30℃. After the casting is completed, the gate of the prepared ingot is sawn off by 200mm. (2) The core layer, brazing layer and anti-corrosion layer are milled separately. The milling amount of each prefabricated layer is 10mm / each of the two large surfaces. After milling, the thickness of the core layer, brazing layer and anti-corrosion layer is 385±2mm. (3) The brazing layer and the anti-corrosion layer after milling are heated separately at a temperature of 540℃ and a holding time of 14h. Then the heated brazing prefabricated layer and the anti-corrosion prefabricated layer are hot rolled to obtain the brazing prefabricated layer and the anti-corrosion prefabricated layer. The brazing prefabricated layer is rolled to 52±2mm and the anti-corrosion prefabricated layer is rolled to 70±2mm. Then the prefabricated layer is cut according to the preparation requirements, placed and cooled naturally. (4) The two large surfaces of the core layer are polished and cleaned. Then the brazing prefabricated layer, the anti-corrosion prefabricated layer and the core prefabricated layer are stacked in sequence. The brazing prefabricated layer and the anti-corrosion prefabricated layer are fixed on both sides of the core prefabricated layer by argon arc welding. The two ends are tied with steel strips to obtain the composite ingot. (5) The composite ingot is cold-pressed in a hot rolling mill. The middle part of the steel strip at both ends of the composite ingot is cold-pressed from the middle to both ends. The rolling speed of cold pressing is 30m / min, and the rolling speed is adjusted downward by 0.5mm per pass. The rolling process is 5 passes. (6) The treated composite ingot is heated to 520℃ and held for 10 hours. Then, the composite layer is rolled into a billet with a thickness of 6.5±0.3mm by a hot rolling mill. The billet is then rolled in a cold rolling mill in passes of 6.5-4.0-2.6-1.6-1.0mm to obtain a semi-finished coil.

[0034] (7) The semi-finished coil is cut off at the edge with cracks and burrs by a rewinding and trimming machine. The trimming width of each side is 80mm. After trimming, the semi-finished coil is rolled in a cold finishing mill in passes of 1.0-0.75-0.58-0.45-0.36-0.28-0.22mm to obtain the coil with the final finished thickness. (8) Use a bending straightening machine to clean the oil stains, aluminum shavings and other impurities on the surface of the coil and optimize the overall pattern. The cleaning water temperature is 80℃ and the cleaning speed is 100m / min. (9) The cleaned roll material is annealed to H24 state in an annealing furnace. Under nitrogen protection, the temperature of the roll material is controlled at 280℃ and held for 5 hours. After being taken out of the furnace, it is naturally cooled and cut to complete the preparation.

[0035] Example 3 Preparation of carbonyl iron: The modifier was dissolved in 200 mL of solvent and ultrasonically treated for 30 min to obtain a surfactant dispersion. Then, carbonyl iron powder was added to the surfactant dispersion and stirred at 60 °C for 1.5 h. Finally, it was washed with deionized water, separated, and dried at 75 °C to obtain pre-modified carbonyl iron. Polydimethylsiloxane was added to 200 mL of n-heptane and ultrasonically treated for 20 min at 60 °C to obtain a mixture. Then, the pre-modified carbonyl iron was added to the mixture and stirred at 60 °C for 1.5 h. It was washed three times alternately with deionized water and n-heptane and finally dried in an oven at 60 °C to obtain modified carbonyl iron. The modifier is glycine, the solvent is deionized water, and the mass ratio of the modifier, carbonyl iron and polydimethylsiloxane is 1:2.15:2.5.

[0036] The core layer consists of 0.5% iron, 0.65% copper, 1.6% manganese, 0.125% zirconium, 0.025% magnesium, 0.025% zinc, 0.025% titanium, with the balance being aluminum and unavoidable impurities.

[0037] The anti-corrosion layer comprises 0.75% silicon, 0.2% iron, 0.05% copper, 1.6% manganese, 4.5% zinc, 0.02% titanium, 0.1% zirconium, 3.17% magnesium, 0.05% scandium, with the balance being aluminum and unavoidable impurities; among which, the iron element is derived from the modified carbonyl iron prepared above.

[0038] The brazing layer is made of 4343 aluminum alloy.

[0039] Preparation of brazed aluminum alloy composite materials: (1) The materials of the brazing layer, core layer and anti-corrosion layer are melted and cast separately according to the proportion. The melting temperature is 770℃ and the stirring is 25min. Then, the refining and degassing are carried out. The refining is carried out at 755℃ for 25min until the hydrogen content of the liquid aluminum water is ≤0.15ml / 100g Al. Then, the casting is carried out at 680℃, the casting speed is 50mm / min, the water pressure is 0.15MPa and the water temperature is 30℃. After the casting is completed, the gate of the prepared ingot is sawn off by 175mm. (2) The core layer, brazing layer and anti-corrosion layer are milled separately. The milling amount of each prefabricated layer is 8.7mm / each of the two large surfaces. After milling, the thickness of the core layer, brazing layer and anti-corrosion layer is 385±2mm. (3) The brazing layer and the anti-corrosion layer after milling are heated separately at a temperature of 530℃ and a holding time of 12h. Then the heated brazing layer and the anti-corrosion layer are hot rolled to obtain the brazing prefabricated layer and the anti-corrosion prefabricated layer. The brazing prefabricated layer is rolled to 52±2mm and the anti-corrosion prefabricated layer is rolled to 70±2mm. Then they are cut according to the preparation requirements, placed and cooled naturally. (4) Grind and clean the two large surfaces of the core layer, then stack the brazed prefabricated layer, the anti-corrosion prefabricated layer and the milled core prefabricated layer in sequence, fix the brazed prefabricated layer and the anti-corrosion prefabricated layer on both sides of the core prefabricated layer by argon arc welding, and tie the two ends with steel strips to obtain a composite ingot. (5) The composite ingot is cold-pressed in a hot rolling mill. The middle part of the steel strip at both ends of the composite ingot is cold-pressed from the middle to both ends. The rolling speed of the cold pressing is 25m / min, and the rolling speed is adjusted downward by 0.5mm per pass. The rolling is performed in 4 passes. (6) The treated composite ingot is heated to 530℃ and held for 12 hours. Then, the composite layer is rolled into a billet with a thickness of 6.5±0.3mm by a hot rolling mill. The billet is then rolled in a cold rolling mill in passes of 6.5-4.0-2.6-1.6-1.0mm to obtain a semi-finished coil.

[0040] (7) The semi-finished coil is cut off at the edge with cracks and burrs by a rewinding and trimming machine. The trimming width of each side is 65mm. After trimming, the semi-finished coil is rolled in a cold finishing mill in passes of 1.0-0.75-0.58-0.45-0.36-0.28-0.22mm to obtain the coil with the final finished thickness. (8) Use a bending straightening machine to clean the oil stains, aluminum shavings and other impurities on the surface of the coil and optimize the overall pattern. The cleaning water temperature is 80℃ and the cleaning speed is 75m / min. (9) The cleaned roll material is annealed to H24 state in an annealing furnace. Under nitrogen protection, the temperature of the roll material is controlled at 265℃ and held for 4.5h. After being taken out of the furnace, it is naturally cooled and cut to complete the preparation.

[0041] Example 4 Example 4 is based on Example 3. The difference between Example 4 and Example 3 is that in the preparation of modified carbonyl iron, the mass ratio between the modifier, carbonyl iron and polydimethylsiloxane is 1:1.9:2.5.

[0042] Example 5 Example 5 is based on Example 3. The difference between Example 5 and Example 3 is that in the preparation of modified carbonyl iron, the mass ratio between the modifier, carbonyl iron and polydimethylsiloxane is 1:2.4:2.5.

[0043] Example 6 Example 6 is based on Example 3. The difference between Example 6 and Example 3 is that in the preparation of modified carbonyl iron, the modifier is hexadecyltrimethylammonium bromide.

[0044] Example 7 Example 7 is based on Example 3. The difference between Example 7 and Example 3 is that in the preparation of modified carbonyl iron, the modifier is sodium dodecylbenzenesulfonate.

[0045] Example 8 Example 8 is based on Example 3. The difference between Example 8 and Example 3 is that the reaction time is 0.5 h when preparing the pre-modified carbonyl iron.

[0046] Example 9 Example 9 is based on Example 3. The difference between Example 9 and Example 3 is that the reaction time for the preparation of pre-modified carbonyl iron is 3 hours.

[0047] Example 10 Example 10 is based on Example 3. The difference between Example 10 and Example 3 is that the reaction temperature is 50°C when preparing the pre-modified carbonyl iron.

[0048] Example 11 Example 11 is based on Example 3. The difference between Example 11 and Example 3 is that the reaction temperature is 70°C when preparing the pre-modified carbonyl iron.

[0049] Example 12 Example 12 is based on Example 3. The difference between Example 12 and Example 3 is that the magnesium content in the anti-corrosion layer is 2.77% and the scandium content is 0.02%.

[0050] Example 13 Example 13 is based on Example 3. The difference between Example 13 and Example 3 is that the magnesium content in the anti-corrosion layer is 3.57% and the scandium content is 0.08%.

[0051] Comparative Example 1 Comparative Example 1 is based on Example 3, but without the addition of magnesium and scandium to the anti-corrosion layer.

[0052] Comparative Example 2 Comparative Example 2 is based on Example 3, but the modified carbonyl iron in Comparative Example 2 was not treated with polydimethylsiloxane.

[0053] Comparative Example 3 Comparative Example 3 is based on Example 3. The iron in the anti-corrosion layer of Comparative Example 3 is derived from ordinary unmodified carbonyl iron.

[0054] Comparative Example 4 Comparative Example 4 is based on Example 3. In Comparative Example 4, the middle part of the steel strips binding the two ends of the composite layer was not cold rolled when preparing the brazed aluminum alloy composite material.

[0055] Performance testing The following performance tests were performed on the samples of Examples 1-13 and Comparative Examples 1-4: (1) Corrosion resistance test Using GB / T 10125-2021 "Artificial Atmosphere Corrosion Test and Salt Spray Test" as the testing standard, the corrosion resistance of the samples was tested. Each sample was tested 3 times, and the average value was taken. The test results were recorded in Table 1.

[0056] (2) Tensile strength test before and after brazing Using GB / T 228.1-2021 as the testing standard, the tensile strength of the samples before and after brazing was tested. The brazing process was 605℃ for 5 minutes. Three samples were taken for each example or comparative example, the average value was taken, and the test results were filled in Table 1.

[0057] Table 1 Performance test results of Examples 1-13 and Comparative Examples 1-4 Data Analysis As shown in Table 1, the CASS salt spray test results for Examples 1-3 were all 220 hours or more. Therefore, the brazed aluminum alloy composite material prepared in this application has good corrosion resistance. The tensile strength of Examples 1-3 before brazing was 215 MPa or more, and the tensile strength after brazing was 175 MPa or more, indicating that the brazed aluminum alloy composite material prepared in this application has good tensile strength.

[0058] In Examples 4 and 5, the mass ratio between the modifier and the carbonyl iron during the preparation of the modified carbonyl iron was not within the range specified in this application. When the content of the modifier was too low, the surface of the carbonyl iron powder was loose, making it difficult to further improve the density. Therefore, the bonding performance of the carbonyl iron was difficult to further improve, and the stability decreased. It also affected the corrosion resistance of the anti-corrosion layer. When the content of the modifier was too high, it affected the overall stability of the system and made it difficult to promote the formation of a dense modified layer on the surface of the carbonyl iron. Therefore, the performance of the prepared anti-corrosion layer decreased, and the tensile strength of the anti-corrosion layer was also affected. Thus, the corrosion resistance and tensile strength of Examples 4 and 5 both decreased.

[0059] In Examples 6 and 7, when preparing modified carbonyl iron, the modifiers were replaced with hexadecyltrimethylammonium bromide and sodium dodecylbenzenesulfonate, respectively. The complex impedance of hexadecyltrimethylammonium bromide and sodium dodecylbenzenesulfonate was difficult to improve significantly after modification, so the corrosion resistance of Examples 6 and 7 decreased significantly.

[0060] In Examples 8 and 9, the reaction times for preparing modified carbonyl iron were not within the range specified in this application. When the reaction time was too short, the coating rate on the surface of carbonyl iron was too small, making it difficult to uniformly form a stable modified layer, and the modification effect was difficult to further improve, thus affecting the stability of the modified carbonyl iron. When the reaction time was too long, the carbonyl iron powder was oxidized by glycine, which reduced the corrosion resistance of the modified carbonyl iron and also affected the mechanical strength of the anti-corrosion layer. Therefore, the corrosion resistance of Examples 8 and 9 decreased, and the tensile strength was also affected.

[0061] In Examples 10 and 11, the reaction temperatures during the preparation of modified carbonyl iron were outside the range specified in this application. When the reaction temperature was too low, the molecular thermal motion speed within the system was too slow, the collision rate between glycine and carbonyl iron decreased, and glycine molecules were difficult to graft onto the surface of carbonyl iron powder, making it difficult to form a uniform and dense modified layer. Consequently, the corrosion resistance of the anti-corrosion layer was difficult to improve, and the tensile strength of the anti-corrosion layer was also affected. When the reaction temperature was too high, the molecular thermal motion speed within the system was too fast, and the collision frequency within the system was too high. Glycine molecules formed an irregular coating layer on the surface of carbonyl iron powder, making it difficult to form a uniform and dense modified layer. Therefore, the stability decreased, the corrosion resistance of the anti-corrosion layer was difficult to improve, and the tensile strength was also affected. Thus, the corrosion resistance and tensile strength of Examples 10 and 11 were both reduced.

[0062] In Examples 13 and 14, the contents of magnesium and scandium are not within the range specified in this application. When the contents of magnesium and scandium are too high or too low, it is difficult for them to further combine with zinc in the system to form a stable oxide film. Therefore, the stability and corrosion resistance of the anti-corrosion layer are reduced, and the performance of Examples 13 and 14 is reduced.

[0063] In Comparative Example 1, the anti-corrosion layer lacks magnesium and scandium, making it difficult to combine with zinc in the system to form a dense oxide film. This makes it difficult to further improve the anti-corrosion performance of the anti-corrosion layer. At the same time, the absence of magnesium makes it difficult to further improve the mechanical properties of the anti-corrosion layer, and the stability of the prepared anti-corrosion layer is difficult to further improve. Therefore, the corrosion resistance and tensile strength of Comparative Example 1 both decrease.

[0064] In Comparative Example 2, the carbonyl iron was not treated with polydimethylsiloxane, making it difficult to further coat the surface of the carbonyl iron. As a result, the corrosion resistance and stability were difficult to improve. The decrease in stability would also affect the overall mechanical strength of the system, and the tensile strength would decrease. Therefore, the performance of Comparative Example 2 was reduced.

[0065] In Comparative Example 3, the source of iron in the anti-corrosion layer was replaced with ordinary unmodified carbonyl iron. The corrosion resistance of the unmodified carbonyl iron was severely reduced, and its stability was difficult to improve further. The tensile strength was also affected. Therefore, the performance of Comparative Example 1 was reduced.

[0066] In Comparative Example 4, the steel strips binding both ends of the composite layer were not cold-rolled in the middle part during the preparation of the brazed aluminum alloy composite material. As a result, the bonding performance between the brazed layer, the core layer and the anti-corrosion layer was difficult to improve further, and the phenomenon of misalignment occurred, which affected the stability of the aluminum alloy composite material. In addition, the air in the middle of the composite layer could not be completely discharged, and bubbles formed in the composite layer, resulting in a decrease in the quality of the finished product.

[0067] This specific embodiment is merely an explanation of this application and is not intended to limit it. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification but must be determined according to the scope of the claims.

Claims

1. A high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators, characterized in that: The device comprises a brazing layer, a core layer, and an anti-corrosion layer arranged sequentially. The core layer comprises the following elemental composition by weight percentage: iron 0.3-0.7%, copper 0.5-0.8%, manganese 1.4-1.8%, zirconium 0.1-0.15%, magnesium ≤0.05%, zinc ≤0.05%, titanium ≤0.05%, with the balance being aluminum and unavoidable impurities. The anti-corrosion layer comprises the following elemental composition by weight percentage: silicon 0.5-1.0%, iron 0.2-0.3%, copper 0-0.1%, manganese 1.4-1.8%, zinc 4.0-5.0%, titanium 0.01-0.03%, zirconium 0.07-0.12%, with the balance being aluminum and unavoidable impurities. The iron element in the anti-corrosion layer is derived from iron carbonyl, which is prepared by modification treatment. The modification treatment method of the iron carbonyl includes the following steps: The modifier was dissolved in a solvent and ultrasonically treated to obtain a surfactant dispersion. Carbonyl iron powder was added to the surfactant dispersion and stirred at a constant temperature for a certain time. After washing and drying, pre-modified carbonyl iron was obtained. Polydimethylsiloxane was added to n-heptane and ultrasonically treated to obtain a mixture. Then, the pre-modified carbonyl iron was added to the mixture and stirred. After washing and drying, modified carbonyl iron was obtained. The modifier includes any one of hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and glycine; The mass ratio of the modifier, carbonyl iron, and polydimethylsiloxane is 1:(2.1-2.2):2.

5.

2. The high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators according to claim 1, characterized in that: The reaction time for preparing the pre-modified carbonyl iron is 1-2 hours.

3. The high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators according to claim 1, characterized in that: The reaction temperature for preparing the pre-modified carbonyl iron is 57-63℃.

4. The high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators according to claim 1, characterized in that: The anti-corrosion layer also includes the following elements by weight percentage: magnesium 1.07-1.27% and scandium 0.04-0.06%.

5. A method for preparing a high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators according to any one of claims 1-4, characterized in that: Includes the following steps: The materials for the brazing layer, core layer, and anti-corrosion layer are melted and cast separately according to the specified proportions. After melting and casting, each layer is milled. The milled brazing layer and anti-corrosion layer are then heated and hot-rolled to obtain the brazing prefabricated layer and anti-corrosion prefabricated layer, respectively. After cooling, the brazing prefabricated layer, core prefabricated layer, and anti-corrosion layer are stacked sequentially. The brazing prefabricated layer and anti-corrosion prefabricated layer are fixed to both sides of the core prefabricated layer by argon arc welding. The two ends are bound with steel strips to obtain a composite ingot. The composite ingot is rolled in a hot rolling mill and then rolled in a cold rolling mill to obtain a semi-finished coil. The edge cracks and burrs of the semi-finished coil are removed, and it is rolled again in a cold finishing mill to obtain the coil of the final finished thickness. Then, the coil surface is cleaned of oil and debris by a tension straightener, and finally annealed in an annealing furnace. After cooling, it is cut to obtain the aluminum alloy composite material.

6. The method for preparing a high-strength, high-corrosion-resistant brazed aluminum alloy composite material for radiators according to claim 5, characterized in that, The rolling process of the composite ingot in a hot rolling mill specifically includes the following steps: The middle part of the steel strips binding the two ends of the composite layer is cold-pressed, with the cold pressing direction from the middle to both ends. The rolling speed of the cold pressing is 20-30m / min, and the rolling is performed in 3-5 passes.

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