Aluminum-iron-copper series high thermal conductivity aluminum alloy material and preparation method and die-casting method thereof

Abstract

The present invention provides an aluminum-iron-copper series high thermal conductivity aluminum alloy material, a preparation method thereof, and a die-casting method. The aluminum alloy material provided by the present invention comprises, by mass percentage, Si≤0.5%; Fe: 1.0-2.0%; Cu: 0.7-2.0%; Mn≤0.05%; Mg≤0.05%; Zn≤0.05%; Ti≤0.05%; Ni≤0.05%; TCB seed alloy addition amount: 0.1-0.6%; Sr: 0.0005-0.06%; Pb≤0.05%; Sn≤0.01%; Cd≤0.01%; the content of each common impurity element is ≤0.05%, and the total impurity content is ≤0.15%; the remainder is Al. The aluminum-iron-copper series high thermal conductivity aluminum alloy material provided by the present invention has relatively excellent die-casting performance, can realize die-casting molding of products containing thin walls, and also has high electrical and thermal conductivity and good heat resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of die-cast aluminum alloys, and in particular relates to an aluminum-iron-copper series high thermal conductivity aluminum alloy material and a preparation method and a die-casting method thereof. Background Art

[0002] The thermal conductivity of pure aluminum is about 237W / (mk). The thermal conductivity of almost all aluminum alloy materials is lower than that of pure aluminum. This is because the addition of any element to the alloy has a greater or lesser negative impact on the thermal conductivity of the material.

[0003] When considering die-cast aluminum alloys, in addition to mechanical properties and thermal conductivity, it's even more important to consider their die-casting properties. The aluminum-silicon series offers the best die-casting performance, with the eutectic being the most effective. Therefore, current research and development of high-thermal-conductivity die-cast aluminum alloys is primarily focused on the aluminum-silicon series. The thermal conductivity of die-cast aluminum alloys has significantly improved, from 120-130 W / (mk) in the early days to 150-160 W / (mk) and, in recent years, to 170-180 W / (mk).

[0004] For example, patent publication number CN115948682A discloses a high-thermal-conductivity aluminum alloy suitable for large, thin-walled heat dissipation cavities in 5G networks. It is characterized by the following components, calculated by mass percentage: Si 8-9%; Fe 0.6-1.0%; Mg 0.1-0.3%; Sr 0.02-0.05%; the balance being Al and unavoidable impurities. This invention belongs to the aluminum-silicon family and requires rare earth refining, rheo-die casting, and heat treatment. The heat-treated die-casting achieves a thermal conductivity of approximately 180 W / (mk).

[0005] Patent publication number CN117187630A discloses a high-thermal-conductivity die-cast aluminum alloy product, its preparation method, and a heat sink. It is characterized by the following components, calculated by mass percentage: Si 7.5-9.0%; Fe 0.70-0.95%; Cu <0.02%; Mg <0.02%; Mn <0.01%; Cr <0.01%; Ti <0.01%; V <0.01%; Sr 0.02-0.04%; the balance being Al and impurity elements. This invention also belongs to the aluminum-silicon system and exhibits excellent die-casting properties. After heat treatment, the thermal conductivity of the die-cast parts can reach 180 W / (mk). However, this material has stringent requirements for the content of impurity elements and requires heat treatment, resulting in high production costs.

[0006] Patent publication number CN117363934A discloses a low-titanium, low-vanadium, hypoeutectic, high-thermal-conductivity Al-Si alloy material and its preparation method. The material comprises, by mass percentage, the following components: Si 6.5-8.5%; Fe 0.65-0.8%; Mg 0.05-0.15%; Sr 0.008-0.02%; RE 0.01-0.05%; B 0.008-0.015%; Ti <0.001%; V <0.002%; and the remaining impurity elements do not exceed 0.15% in total, with individual impurity elements not exceeding 0.05%, with the remainder being Al. This invention also belongs to the aluminum-silicon family and exhibits excellent die-casting properties. The thermal conductivity of the aluminum alloy can reach 180 W / (mk). The alloy requires that the Ti and V elements be kept within a relatively low range.

[0007] In summary, the high thermal conductivity die-cast aluminum alloy materials currently under development are mainly concentrated in Al-Si alloys. The alloys have very strict requirements on impurity elements such as V, Ti, and Cr, which requires a high purity of the alloy. Existing Al-Si die-cast aluminum alloy materials usually add a small amount of iron to avoid sticking, or add a small amount of copper to improve the mechanical properties of the material. However, iron and copper elements in Al-Si die-cast aluminum alloy materials will have a great negative impact on the thermal conductivity of the material, causing the thermal conductivity of the material to decrease. Therefore, the thermal conductivity of Al-Si die-cast aluminum alloys, especially eutectic die-cast aluminum alloys, is difficult to exceed 180W / (mk). In order to obtain higher thermal conductivity, heat treatment is required.

[0008] With the continuous development and progress of science and technology, the thermal conductivity of aluminum-silicon alloy materials can no longer meet the market demand. At present, domestic research has also been conducted on high thermal conductivity die-cast aluminum alloy materials other than aluminum-silicon series, and some results have been achieved. For example:

[0009] Patent publication number CN108130456A discloses a high thermal conductivity die-cast aluminum alloy material and its preparation method, characterized by comprising the following components, by mass percentage: Si < 0.2%, Fe 0.8-1.8%, Ni 0.2-0.8%, La 0.1-0.4%, Mg < 0.2%, Cu < 0.2%, Mn < 0.2%, Zn < 0.2%, Co ≤ 0.3%, Pb ≤ 0.1%, Sn ≤ 0.01%, the total amount of other impurities not exceeding 0.3%, and the balance being Al. This invention has excellent thermal conductivity, with a thermal conductivity coefficient of up to 220W / (mk), and is very excellent in thermal conductivity. It belongs to the AlFeNi series, and nickel has a relatively small direct effect on the fluidity of aluminum liquid. Therefore, the fluidity of this alloy material is poor, and the die-casting performance is average. Only thick-walled fire dividers can be die-cast, and it is difficult to form thin-walled workpieces with high teeth. In addition, it contains the precious metal Ni, which has a high production cost.

[0010] CN108929975A discloses an aluminum alloy material and a preparation method thereof, characterized in that, by mass percentage, it includes the following components: Si 2.0-4.5%, Fe 0.6-1.5%, Cu <0.3%, Mn <0.3%, Mg <0.3%, Zn <0.3%, Ni 0.2-1.2%, Pb ≤ 0.1%, Sn ≤ 0.01%, Cd ≤ 0.01%, and the balance is Al. The invention has good thermal conductivity and high temperature resistance. It has excellent heat resistance and can reach a heat resistance test of 550°C * 3 hours. However, its thermal conductivity coefficient is still difficult to exceed 180W / (mk). In addition, it belongs to the AlSiFeNi system, has poor fluidity and general die-casting performance. It is difficult to form workpieces with thin walls and high teeth. It also contains precious metal Ni, which has a high production cost.

[0011] Therefore, for some products with thin walls and need to work at high temperatures, there is a lack of better basic alloy materials, and there is a lack of a die-cast aluminum alloy material that can smoothly die-cast thin-walled and high-tooth workpieces, and has a thermal conductivity exceeding 180W / (mk), excellent high-temperature resistance, and low cost. Summary of the Invention

[0012] In view of the shortcomings of the existing technology, the present invention provides an aluminum-iron-copper series high thermal conductivity aluminum alloy material with excellent die-casting performance, high thermal conductivity and high temperature resistance, as well as a preparation method and a die-casting method thereof.

[0013] The invention provides an aluminum-iron-copper series high-thermal conductivity aluminum alloy material. The aluminum alloy material comprises, by mass percentage, Si≤0.5%; Fe: 1.0-2.0%; Cu: 0.7-2.0%; Mn≤0.05%; Mg≤0.05%; Zn≤0.05%; Ti≤0.05%; Ni≤0.05%; TCB seed alloy addition amount: 0.1-0.6%; Sr: 0.0005-0.06%; Pb≤0.05%; Sn≤0.01%; Cd≤0.01%; the content of each common impurity element is ≤0.05%, and the total impurity content is ≤0.15%; and the rest is Al.

[0014] Preferably, the TCB seed crystal comprises, by mass percentage, Ti: 1.8-2.2%, C: 0.28-0.35%, B: 0.28-0.35%, Mn: ≤0.1%, Fe: ≤0.3%, Si: ≤0.3%, V: ≤0.1%, and the remainder is Al.

[0015] Preferably, the aluminum alloy material contains 1.5-2.0% Fe.

[0016] Preferably, the aluminum alloy material has Si≤0.1%.

[0017] Preferably, the aluminum alloy material contains Cu: 1-2.0%.

[0018] Preferably, the main components and process conditions of the aluminum alloy material satisfy the following functional relationship:

[0019] Y k =129.482+7.42a+31.505b+7.613c-46.378d

[0020] Y Q =60.143+4.83a+14.983b–3.592c+125.73d

[0021] Y S =19.538-3.303a–2.591b-3.304c+2.166d

[0022] Y Y =26.542+5.911a+9.53b–6.96c+66.956d

[0023] Y D =32.288–1.11a–2.174b+2.38c–3.207d

[0024] Y R =8.013Y D –20.208

[0025] Among them, a, b, c, and d represent the contents of Fe, Cu, TCB seeds, and Sr in the formula, respectively. K is the tensile strength, Y Q is the yield strength, Y S is the elongation, Y Y is the hardness, Y D is the conductivity, Y R is the thermal conductivity.

[0026] The present invention also provides a method for preparing an aluminum-iron-copper series high thermal conductivity aluminum alloy material, the preparation method comprising the following steps:

[0027] S1. Add 85-90% of the total amount of aluminum ingots, melt and heat to 850-900℃, add iron agent in several times, let it stand after each addition, and then stir;

[0028] S2. Add the preheated copper agent, let it stand for 10-20 minutes, and stir for 5-10 minutes;

[0029] S3. Add the remaining aluminum ingots and adjust the aluminum liquid temperature to 740-760℃;

[0030] S4. Use refining flux to refine, remove slag, and check for pinholes, which should reach level 1. When the aluminum liquid temperature is 720-750℃, add preheated TCB seeds;

[0031] S5. Aluminum ingots are cast at a temperature of 720±10℃. During the casting process, argon or nitrogen is used to pass through a breathable brick with a pore size of 15-25μm to perform online degassing at the bottom of the filter box or launder, and ensure that the pinhole is no higher than level 2.

[0032] Preferably, the copper agent is red copper or Al-Cu master alloy.

[0033] Preferably, in step S4, the specific steps of refining with a refining agent are: using argon or nitrogen as a carrier gas, adding a refining agent in an amount of 0.1-0.2% of the total amount of the aluminum liquid, and performing refining and purification;

[0034] In step S4, the specific steps of slag removal are as follows: after refining and purification, the surface slag is removed for the first time, the aluminum liquid temperature is controlled at 740-760°C, and argon or nitrogen is used for degassing for 10-30 minutes before the second slag removal;

[0035] In step S1, the iron agent is added in multiple times, and after each addition, the mixture is allowed to stand for 10-20 minutes and stirred for 5-10 minutes.

[0036] The present invention also provides a die-casting method for an aluminum-iron-copper series high thermal conductivity aluminum alloy material, the die-casting method comprising the following steps:

[0037] (1) Aluminum melt temperature (remelting temperature) before die casting ≤ 760℃;

[0038] (2) Die-cast aluminum liquid temperature 715±10℃;

[0039] (3) Die casting mold temperature 200±10℃;

[0040] (4) Degas the aluminum melt with argon or nitrogen for 20-30 minutes before die casting, and remove the slag after degassing;

[0041] During the die casting process, no cold material such as return material is added into the furnace;

[0042] Iron tools used in the die casting process need to be coated and dried.

[0043] The aluminum-iron-copper series high thermal conductivity aluminum alloy material provided by the present invention has relatively good die-casting performance, can realize die-casting of products containing thin walls, and also has high electrical and thermal conductivity and good heat resistance. In terms of its die-casting performance, it is closer to the die-casting performance of aluminum-silicon alloy, and can smoothly die-cast to obtain workpieces containing thin walls. In terms of its thermal conductivity, it breaks through the bottleneck of the thermal conductivity coefficient of aluminum-silicon alloy. Therefore, the high thermal conductivity aluminum alloy material prepared by the present invention provides a basic material for processing workpieces that require thin-wall die-casting and require a higher thermal conductivity coefficient, and the improvement of the basic material provides more possibilities for back-end manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of the preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals indicate the same parts throughout the accompanying drawings, and the drawings are not drawn to scale with actual size. The emphasis is on illustrating the subject matter of the present invention.

[0045] Figure 1 This is a photo of the radiator die-casted from aluminum alloy material prepared in Example 1. DETAILED DESCRIPTION

[0046] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0047] Embodiments of the present invention provide an aluminum-iron-copper series high thermal conductivity aluminum alloy material, wherein the aluminum alloy material comprises, by mass percentage, Si≤0.5%; Fe: 1.0-2.0%; Cu: 0.7-2.0%; Mn≤0.05%; Mg≤0.05%; Zn≤0.05%; Ti≤0.05%; Ni≤0.05%; TCB seed alloy addition amount: 0.1-0.6%; Sr: 0.0005-0.06%; Pb≤0.05%; Sn≤0.01%; Cd≤0.01%; a single common impurity element is ≤0.05%, and the total impurity content is ≤0.15%; the rest is Al.

[0048] The aluminum-iron-copper series high thermal conductivity die-cast aluminum alloy material provided by the embodiment of the present invention has excellent die-casting molding performance, and it can realize a plurality of relatively thin heat dissipation fins, which can be die-casted relatively smoothly. The aluminum-iron-copper series high thermal conductivity die-cast aluminum alloy material prepared by the present invention has a casting thermal conductivity coefficient of 208.159W / (mk) and a casting electrical conductivity of 28.67MS / m in the material casting state. In the die-casting state, the die-casting thermal conductivity coefficient reaches 195.764W / (mk), and the die-casting electrical conductivity reaches 26.96MS / m, and it can pass the heat resistance test: 500℃*3 hours without deformation or discoloration. The aluminum-iron-copper series high thermal conductivity die-cast aluminum alloy material prepared by the present invention can realize better die-casting molding containing a plurality of relatively thin heat dissipation fins, and provides a basic die-casting moldable material for workpieces containing thin walls and needing to work at high temperatures. It breaks through the bottleneck of thermal conductivity of aluminum-silicon alloy materials with better die-casting performance.

[0049] In aluminum-silicon alloy materials, the addition of iron and copper elements to form an Al-Si-Fe-Cu alloy often has a significant negative impact on the thermal conductivity and electrical conductivity of the alloy material. However, in the aluminum-iron-copper die-cast aluminum alloy material of the present invention, the silicon content is controlled within a relatively low proportion range, and the aluminum-iron-copper alloy material is formed by adding appropriate amounts of iron and copper elements. In this material system, iron and copper do not have a significant negative impact on the thermal conductivity of the material, and do not significantly reduce the thermal conductivity of the material. This allows the aluminum-iron-copper die-cast aluminum alloy material to maintain a relatively high thermal conductivity, and can maximize the role of iron and copper elements.

[0050] The alloy material provided by the present invention is an aluminum-iron-copper die-cast aluminum alloy material. Through research, it is found that iron and copper in this system do not have a negative impact on the thermal and electrical conductivity of the material. Therefore, iron and copper are selected as the main elements of the aluminum alloy, which solves the problem of good die-casting formability and mechanical properties of the material while ensuring high thermal conductivity of the material.

[0051] First, the Fe content is selected near the Al-Fe eutectic point. The solid solubility of iron in this aluminum alloy system is low, resulting in minimal lattice distortion in the aluminum matrix and, consequently, minimal negative impact on its thermal conductivity. If added in the appropriate amount, it will not significantly affect the thermal conductivity of the aluminum, thus enabling the aluminum alloy to maintain good thermal and electrical conductivity. Furthermore, the appropriate iron content ensures good fluidity of the molten aluminum, providing the aluminum alloy with excellent die-casting properties.

[0052] Secondly, by adding an appropriate amount of Cu, the negative impact of copper in this system is relatively small, and it will not significantly affect the thermal conductivity of aluminum, thus enabling the aluminum alloy material to maintain good thermal and electrical conductivity. At the same time, by adding an appropriate amount of Cu, which is solid-dissolved in the aluminum matrix, the strength and hardness of the alloy can be improved. Furthermore, the addition of copper can lower the melting point and viscosity of the aluminum alloy, thereby facilitating the flow of molten aluminum, further enhancing the excellent die-casting properties of the aluminum alloy material, and further ensuring that the die-cast aluminum alloy material prepared by the present invention can simultaneously achieve a high thermal conductivity coefficient and can die-cast thin-walled workpieces with a certain tooth height.

[0053] Based on research into the varying effects of Fe and Cu on thermal and electrical conductivity in various aluminum alloy systems, the inventors discovered that the negative impact of Fe and Cu in the Al-Fe-Cu system is significantly less than in the Al-Si-Fe-Cu system. Therefore, Fe and Cu were selected as the primary alloying elements to form the Al-Fe-Cu system's high thermal conductivity die-cast aluminum alloy. The inventors primarily studied and compared the following aspects:

[0054] 1. Phase stability and structure: In Al-Fe-Cu alloys, Fe and Cu can form a solid solution with limited solid solubility in the aluminum matrix. Although this will also increase lattice distortion, compared to Al-Si-Fe-Cu alloys, due to the lack of strong influence of silicon, the formation of intermetallic compounds is less, so the impact on thermal conductivity and electrical conductivity is relatively mild. In Al-Si-Fe-Cu alloys, when the silicon content is high, silicon compounds and eutectic phases are easily formed. These phases usually have poor thermal and electrical conductivity. In addition, Si forms more complex intermetallic compounds with Fe and Cu. The appearance of these compounds significantly reduces the thermal conductivity and electrical conductivity of the alloy.

[0055] 2. Lattice constant and atomic size: The atomic radius of Si (0.118nm) differs significantly from that of aluminum (0.143nm). When Si is added to an Al matrix, due to the large difference in atomic radius, the lattice constant increases, making it more likely to cause lattice distortion and increased dislocations, leading to severe lattice disorder, thereby hindering the transmission of electrons and phonons and reducing the thermal and electrical conductivity of the alloy. Although Fe and Cu also cause some lattice distortion, the atomic radius of Fe (0.126nm) and Cu (0.128nm) is less different from that of aluminum, so their impact is smaller than that of Si. Therefore, in pure Al-Fe-Cu alloys, the impact on thermal conductivity and electrical conductivity is not as significant.

[0056] 3. Phase interfaces and defects: In Al-Si-Fe-Cu alloys, the addition of Si often leads to the formation of numerous phase interfaces, which become centers for electron and phonon scattering, reducing thermal and electrical conductivity. However, the intermetallic compounds formed by Fe and Cu in Al-Fe-Cu alloys are relatively stable and evenly dispersed, which reduces the number of large phase interfaces and defects, thus having a less negative impact on thermal and electrical conductivity.

[0057] 4. Solubility and phase composition: In Al-Si-Fe-Cu alloys, Si has limited solubility in aluminum and rapidly precipitates in a supersaturated state, forming a secondary phase with low thermal and electrical conductivity. In Al-Fe-Cu alloys, Fe and Cu, at appropriate concentrations, can form a good solid solution in aluminum. Although some intermetallic compounds are formed, their negative impact on thermal and electrical conductivity is less than that of Si.

[0058] Therefore, the reason why the effects of Fe and Cu on thermal and electrical conductivity in Al-Si-Fe-Cu alloys are greater than those in Al-Fe-Cu alloys is mainly because the addition of Si changes the microstructure of the alloy and enhances the negative effects of Fe and Cu on thermal and electrical conductivity. In Al-Fe-Cu alloys without Si, the effects of Fe and Cu depend more on their own solubility, phase formation and influence on the lattice structure.

[0059] The addition of different Sr is mainly used to adjust and balance the relationship between several properties (especially mechanical properties).

[0060] In a preferred embodiment, the TCB seed alloy comprises, by mass percentage, 1.8-2.2% Ti, 0.28-0.35% C, 0.28-0.35% B, ≤0.1% Mn, ≤0.3% Fe, ≤0.3% Si, ≤0.1% V, and the remainder Al. The addition of a certain amount of TCB seed alloy refines the α-Al phase, resolves grain size unevenness and composition segregation, reduces metallurgical defects, and improves and stabilizes the material's thermal conductivity, overall mechanical properties, and product quality.

[0061] In a preferred embodiment, the Fe content in the aluminum alloy material is 1.5-2.0%.

[0062] In a preferred embodiment, the Si content in the aluminum alloy material is ≤ 0.1%.

[0063] In a preferred embodiment, the aluminum alloy material contains Cu: 1-2.0%.

[0064] In a preferred embodiment, the main components of the aluminum alloy material and the process conditions satisfy the functional relationship expressed by the following mathematical model:

[0065] Y k =129.482+7.42a+31.505b+7.613c-46.378d

[0066] Y Q =60.143+4.83a+14.983b–3.592c+125.73d

[0067] Y S =19.538-3.303a–2.591b-3.304c+2.166d

[0068] Y Y =26.542+5.911a+9.53b–6.96c+66.956d

[0069] Y D =32.288–1.11a–2.174b+2.38c–3.207d

[0070] Y R =8.013Y D –20.208

[0071] Among them, a, b, c, d represent the contents of Fe, Cu, TCB seeds and Sr in the formula respectively, and Y K is the tensile strength (MPa), Y Q is the yield strength (MPa), Y S is the elongation (%), Y Y is the hardness (HBW), Y D is the conductivity (MS / m), Y R is the thermal conductivity (W / (mk)). Within the controlled range of this material, the thermal conductivity and electrical conductivity are positively correlated, and can simultaneously ensure good thermal conductivity and high electrical conductivity.

[0072] The method for preparing a high-thermal-conductivity die-cast aluminum alloy material in the aluminum-iron-copper system provided in this embodiment is based on the study of the degree of influence and effect of the Fe and Cu elements on the performance of the aluminum alloy material of the present invention, as well as a comparison with the Al-Si-Fe-Cu system. This method forms a method for preparing a high-thermal-conductivity die-cast aluminum alloy material based on the Al-Fe-Cu system, and conforms to the above-mentioned mathematical model within the controlled range. In the model, the standard deviation of the influence of each variable on the performance within the controlled range falls within ±2σ. In the preparation method provided in this embodiment, the composition of the material used and the specific properties of the material satisfy the above-mentioned functional relationship.

[0073] In the development of new aluminum alloy materials, basic compositions are often designed by studying the properties of each element. Experimentation is then conducted in conjunction with specific processes to achieve the desired performance or combination of properties of the newly developed material. Because the effects of elements and their interactions on performance, especially on multiple performance indicators, often vary—some are positively correlated, some are negatively correlated, and some have significant impacts, while others have minor effects—analysis can be complex. The applicant's patent application number 201910476108.0, publication number CN110232233B, entitled "A Method for Designing Die-Casting Aluminum Alloy Materials," discloses a design method for alloy material development. This method allows for designing the composition ratios of die-cast aluminum alloys that achieve the desired specific properties, as well as quantifiable process parameters. Based on this, the applicant further researched and discovered that the formula content used in the preparation method for the aluminum-iron-copper high-thermal-conductivity die-cast aluminum alloy material provided by the present invention satisfies the aforementioned functional relationship between the desired properties. Within the controlled range of this material, the thermal conductivity and electrical conductivity are positively correlated, enabling both good thermal conductivity and high electrical conductivity to be achieved simultaneously. When the material prepared by the preparation method provided by the present invention can still maintain a high level of electrical conductivity after surface treatment, it shows that the aluminum alloy material of the present invention exhibits excellent electrical conductivity and thus also has excellent thermal conductivity which is positively correlated therewith.

[0074] The present invention also provides a method for preparing an aluminum-iron-copper alloy material with high thermal conductivity, comprising the following steps:

[0075] S1. Add 85-90% of the total amount of aluminum ingots, melt and heat to 850-900℃, add iron agent in several times, let it stand after each addition, and then stir;

[0076] S2. Add the preheated copper agent, let it stand for 10-20 minutes, and stir for 5-10 minutes;

[0077] S3. Add the remaining aluminum ingots and adjust the aluminum liquid temperature to 740-760℃;

[0078] S4. Use refining flux to refine, remove slag, and check for pinholes, which should reach level 1. When the aluminum liquid temperature is 720-750℃, add preheated TCB seeds;

[0079] S5. Aluminum ingots are cast at a temperature of 720±10℃. During the casting process, argon or nitrogen is used to pass through a breathable brick with a pore size of 15-25μm to perform online degassing at the bottom of the filter box or launder, and ensure that the pinhole is no higher than level 2.

[0080] In a preferred embodiment, the copper agent is red copper or an Al-Cu master alloy.

[0081] In a preferred embodiment, in step S4, the specific steps of refining with a refining agent are as follows: using argon or nitrogen as a carrier gas, adding a refining agent in an amount of 0.1-0.2% of the total amount of the aluminum liquid, and performing refining and purification;

[0082] In a preferred embodiment, the specific steps of slag removal are: removing surface slag for the first time after refining and purification, controlling the aluminum liquid temperature at 740-760°C, and removing slag for the second time after degassing with argon or nitrogen for 10-30 minutes.

[0083] In a preferred embodiment, in step S1, the iron agent is added in multiple times, and after each addition, the mixture is allowed to stand for 10-20 minutes and stirred for 5-10 minutes.

[0084] In a preferred embodiment, the method for preparing an aluminum-iron-copper series high thermal conductivity aluminum alloy material specifically comprises the following steps:

[0085] (1) Add 85-90% aluminum ingot, melt and heat to 850-900℃.

[0086] (2) When the temperature is 850-900℃, add the iron agent in 4 times. After each addition, let it stand for 10-20 minutes and stir for 5-10 minutes.

[0087] (3) Add the preheated copper agent (red copper or Al-Cu intermediate alloy), let it stand for 10-20 minutes, and stir for 5-10 minutes.

[0088] (4) Take samples for testing, and proceed to the next step if the ingredients are qualified.

[0089] (5) Add the remaining aluminum ingots and adjust the aluminum liquid temperature to 740-760℃.

[0090] (6) Using argon or nitrogen as the carrier gas, adding a refining agent in an amount of 0.1-0.2% of the total amount of the aluminum liquid for refining and purification.

[0091] (7) Remove surface scum for the first time.

[0092] (8) When the aluminum liquid temperature is 740-760℃, use argon or nitrogen to degas for 10-30 minutes, then remove the slag for the second time and check for pinholes. The requirement is to reach level 1.

[0093] (9) When the aluminum liquid temperature is 720-750℃, add preheated TCB seed crystals and let it stand for 5-10 minutes.

[0094] (10) The aluminum liquid temperature is within the range of 720±10℃ for casting aluminum ingots.

[0095] (11) During the casting process, argon or nitrogen is used to pass through a 15-25 μm pore size air brick at the bottom of the filter box or flow channel for online degassing, and ensure that the pinhole is no higher than level 2.

[0096] In a preferred embodiment, the present invention also provides a die-casting method for an aluminum-iron-copper series high thermal conductivity aluminum alloy material, comprising the following steps:

[0097] (1) The aluminum melt temperature (remelting temperature) before die casting is ≤760℃.

[0098] (2) The temperature of die-cast aluminum liquid is 715±10℃. The wall thickness of die-casting parts is on the lower limit, and the wall thickness of die-casting parts is on the upper limit.

[0099] (3) The die casting mold temperature is 200±10℃. The die casting wall thickness is on the lower limit, and the die casting wall thickness is on the upper limit.

[0100] (4) Degas the aluminum melt with argon or nitrogen for 20-30 minutes before die casting. Remove slag after degassing.

[0101] (5) During the die-casting process, cold materials such as return materials are not added to the furnace to avoid contamination of the melt.

[0102] (6) Iron tools need to be coated and dried to prevent the aluminum melt from inhaling air during the die casting process.

[0103] In order to have a further understanding and recognition of the technical solution of the present invention, several preferred embodiments are listed and described in further detail.

[0104] Example 1:

[0105] Calculated by mass percentage: Si: 0.032%; Fe: 1.5%; Cu: 1.31%; Mn: 0.0068%; Mg: 0.0022%; Zn: 0.0102%; Ti: 0.014%; B: 0.0042; Ni: 0.0047%; Sr: 0.0007%; Pb: 0.0034%; Sn: 0.0048%; Cd: 0.0001%; TCB seed alloy addition amount: 0.3%; the single common impurity element is ≤0.05%, and the total impurity content is ≤0.15%; the rest is Al.

[0106] According to the above ratio, the aluminum alloy is prepared as follows:

[0107] (1) Clean the furnace bottom and walls to avoid impurities; add 88% aluminum ingots, start the fire to melt and heat to 885℃.

[0108] (2) When the temperature is 885℃, add the iron agent in 4 times. After each addition, let it stand for 15 minutes and stir for 8 minutes.

[0109] (3) Add the preheated copper agent (red copper), let it stand for 15 minutes, and stir for 8 minutes.

[0110] (4) Take samples for testing, and proceed to the next step if the ingredients are qualified.

[0111] (5) Add the remaining aluminum ingots and adjust the aluminum liquid temperature to 756℃.

[0112] (6) Nitrogen is used as the carrier gas, and a refining agent is added in an amount of 0.15% of the total amount of the aluminum liquid for refining and purification.

[0113] (7) Remove surface scum for the first time.

[0114] (8) The aluminum liquid temperature is 752℃. After 25 minutes of nitrogen degassing, the surface slag is removed for the second time and the pinholes are checked to reach level 1.

[0115] (9) When the aluminum liquid temperature is 740℃: add preheated TCB seed crystals and let it stand for 8 minutes.

[0116] (10) The aluminum liquid temperature is 725℃ when casting.

[0117] (11) During the casting process, nitrogen is used to pass through a 15-25 μm pore size air brick at the bottom of the filter box for online degassing, and the pinholes are ensured to be no higher than level 2.

[0118] Example 2:

[0119] Calculated by mass percentage: Si: 0.06%; Fe: 1.97%; Cu: 1.21%; Mn: 0.0088%; Mg: 0.0042%; Zn: 0.0333%; Ti: 0.01%; B: 0.006%; Ni: 0.0034%; Sr: 0.0008%; Pb: 0.0036%; Sn: 0.0043%; Cd: 0.0001%; TCB seed alloy addition amount: 0.3%; the single common impurity element is ≤0.05%, and the total impurity content is ≤0.15%; the rest is Al.

[0120] According to the above ratio, the aluminum alloy is prepared as follows:

[0121] (1) Clean the furnace bottom and walls to avoid impurities; add 85% aluminum ingots, start melting and heat to 877℃.

[0122] (2) When the temperature is 877°C, add the iron agent in 4 times. After each addition, let it stand for 15 minutes and stir for 8 minutes.

[0123] (3) Add the preheated copper agent (red copper), let it stand for 15 minutes, and stir for 8 minutes.

[0124] (4) Take samples for testing, and proceed to the next step if the ingredients are qualified.

[0125] (5) Add the remaining aluminum ingots and adjust the aluminum liquid temperature to 758℃.

[0126] (6) Nitrogen is used as the carrier gas, and a refining agent is added in an amount of 0.15% of the total amount of the aluminum liquid for refining and purification.

[0127] (7) Remove surface scum for the first time.

[0128] (8) The aluminum liquid temperature is 753℃. After 25 minutes of nitrogen degassing, the surface slag is removed for the second time and the pinholes are checked to reach level 1.

[0129] (9) When the aluminum liquid temperature is 740℃: add preheated TCB seed crystals and let it stand for 8 minutes.

[0130] (10) The aluminum liquid temperature is 728℃ when casting.

[0131] (11) During the casting process, nitrogen is used to pass through a 15-25 μm pore size air brick at the bottom of the filter box for online degassing, and the pinholes are ensured to be no higher than level 2.

[0132] Example 3:

[0133] Calculated by mass percentage: Si: 0.028%; Fe: 1.5%; Cu: 1.3%; Mn: 0.0066%; Mg: 0.0039%; Zn: 0.0103%; Ti: 0.014%; B: 0.0039; Ni: 0.0032%; Sr: 0.025%; Pb: 0.0035%; Sn: 0.0042%; Cd: 0.0001%; TCB seed alloy addition amount: 0.3%; the single common impurity element is ≤0.05%, and the total impurity content is ≤0.15%; the rest is Al.

[0134] According to the above ratio, the aluminum alloy is prepared as follows:

[0135] (1) Clean the furnace bottom and walls to avoid impurities; add 87% aluminum ingots, start the fire to melt and heat to 891℃.

[0136] (2) When the temperature is 891°C, add the iron agent in 4 times. After each addition, let it stand for 15 minutes and stir for 8 minutes.

[0137] (3) Add the preheated copper agent (red copper), let it stand for 15 minutes, and stir for 8 minutes.

[0138] (4) Take samples for testing, and proceed to the next step if the ingredients are qualified.

[0139] (5) Add the remaining aluminum ingots and adjust the aluminum liquid temperature to 757℃.

[0140] (6) Nitrogen is used as the carrier gas, and a refining agent is added in an amount of 0.15% of the total amount of the aluminum liquid for refining and purification.

[0141] (7) Remove surface scum for the first time.

[0142] (8) The aluminum liquid temperature is 752℃. After 25 minutes of nitrogen degassing, the surface slag is removed for the second time and the pinholes are checked to reach level 1.

[0143] (9) When the aluminum liquid temperature is 742℃: add preheated TCB seed crystals and let it stand for 8 minutes.

[0144] (10) The aluminum liquid temperature is 725℃ when casting.

[0145] (11) During the casting process, nitrogen is used to pass through a 15-25 μm pore size air brick at the bottom of the filter box for online degassing, and the pinholes are ensured to be no higher than level 2.

[0146] Example 4:

[0147] Calculated by mass percentage: Si: 0.061%; Fe: 1.99%; Cu: 1.20%; Mn: 0.0088%; Mg: 0.0048%; Zn: 0.0392%; Ti: 0.008%; B: 0.0055; Ni: 0.0033%; Sr: 0.012%; Pb: 0.0034%; Sn: 0.0041%; Cd: 0.0001%; TCB seed alloy addition amount: 0.3%; the common impurity elements are individually ≤0.05%, and the total impurity content is ≤0.15%; the rest is Al.

[0148] According to the above ratio, the aluminum alloy is prepared as follows:

[0149] (1) Clean the furnace bottom and walls to avoid impurities; add 90% aluminum ingots, start melting and heat to 868℃.

[0150] (2) When the temperature is 868°C, add the iron agent in 4 times. After each addition, let it stand for 15 minutes and stir for 8 minutes.

[0151] (3) Add the preheated copper agent (red copper), let it stand for 15 minutes, and stir for 8 minutes.

[0152] (4) Take samples for testing, and proceed to the next step if the ingredients are qualified.

[0153] (5) Add the remaining aluminum ingots and adjust the aluminum liquid temperature to 755℃.

[0154] (6) Nitrogen is used as the carrier gas, and a refining agent is added in an amount of 0.15% of the total amount of the aluminum liquid for refining and purification.

[0155] (7) Remove surface scum for the first time.

[0156] (8) When the aluminum liquid temperature is 752℃, nitrogen degassing is used for 25 minutes before removing the surface slag for the second time and checking for pinholes. The requirement is to reach level 1.

[0157] (9) When the aluminum liquid temperature is 745℃: add preheated TCB seed crystals and let it stand for 8 minutes.

[0158] (10) The aluminum liquid temperature is 727℃ when casting.

[0159] (11) During the casting process, nitrogen is used to pass through a 15-25 μm pore size air brick at the bottom of the filter box for online degassing, and the pinholes are ensured to be no higher than level 2.

[0160] Example 5:

[0161] Calculated by mass percentage: Si: 0.0379%; Fe: 1.85%; Cu: 1.28%; Mn: 0.0002%; Mg: 0.0014%; Zn: 0.0211%; Ti: 0.0084%; B: 0.0018; Ni: 0.0031%; Sr: 0.0009; Pb: 0.0032%; Sn: 0.0037%; Cd: 0.0001%; TCB seed alloy addition amount: 0.3%; the single common impurity element is ≤0.05%, and the total impurity content is ≤0.15%; the rest is Al.

[0162] According to the above ratio, the aluminum alloy is prepared as follows:

[0163] (1) Clean the furnace bottom and walls to avoid impurities; add 88% aluminum ingots, start melting and heat to 880℃.

[0164] (2) When the temperature is 880℃, add the iron agent in 4 times. After each addition, let it stand for 15 minutes and stir for 8 minutes.

[0165] (3) Add the preheated copper agent (red copper), let it stand for 15 minutes, and stir for 8 minutes.

[0166] (4) Take samples for testing, and proceed to the next step if the ingredients are qualified.

[0167] (5) Add the remaining aluminum ingots and adjust the aluminum liquid temperature to 756℃.

[0168] (6) Nitrogen is used as the carrier gas, and a refining agent is added in an amount of 0.15% of the total amount of the aluminum liquid for refining and purification.

[0169] (7) Remove surface scum for the first time.

[0170] (8) When the aluminum liquid temperature is 751℃, nitrogen degassing is used for 25 minutes, and then the surface slag is removed for the second time, and the pinholes are checked, which is required to reach level 1.

[0171] (9) When the aluminum liquid temperature is 743℃: add preheated TCB seed crystals and let it stand for 8 minutes.

[0172] (10) The aluminum liquid temperature is 726℃ when casting.

[0173] (11) During the casting process, nitrogen is used to pass through a 15-25 μm pore size air brick at the bottom of the filter box for online degassing, and the pinholes are ensured to be no higher than level 2.

[0174] Comparative Example

[0175] Comparative Example 1: The only difference between Comparative Example 1 and Example 1 is that the Fe content in Comparative Example 1 is 0.8%, and the rest of the formula and preparation method are the same as those in Example 1.

[0176] Comparative Example 2: The only difference between Comparative Example 2 and Example 2 is that the Fe content in Comparative Example 2 is 2.5%, and the rest of the formula and preparation method are the same as those in Example 2.

[0177] Comparative Example 3: The only difference between Comparative Example 3 and Example 3 is that the Cu content in Comparative Example 3 is 0.5%, and the rest of the formula and preparation method are the same as those in Example 3.

[0178] Comparative Example 4: The only difference between Comparative Example 4 and Example 4 is that the Cu content in Comparative Example 4 is 2.5%, and the rest of the formula and preparation method are the same as those in Example 4.

[0179] Comparative Example 5: The only difference between Comparative Example 5 and Example 5 is that no TCB is added in Comparative Example 5, and the rest of the formula and preparation method are the same as those in Example 5.

[0180] Comparative Example 6: The only difference between Comparative Example 6 and Example 5 is that Si=7.0% is added in Comparative Example 6, and the rest of the formula and preparation method are the same as those in Example 5.

[0181] Comparative Example 7: A380 aluminum alloy material, composition: Cu 3.0-4.0%; Si 7.5-9.5%; magnesium Mg≤0.1; Fe≤2.0; Zn≤3.0; manganese Mn≤0.5; Ni≤0.5Max; Sn≤0.35; Al balance.

[0182] The aluminum alloy materials obtained by casting Examples 1-5 were tested for their as-cast thermal conductivity, as-cast electrical conductivity, and as-cast hardness. The tests showed that the aluminum alloy materials prepared in Examples 1-5 all met the following performance requirements: as-cast thermal conductivity ≥ 205 W / (mk), as-cast electrical conductivity ≥ 27.5 MS / m, as-cast hardness ≥ 45 HBW, and all passed the heat resistance test: no deformation or discoloration at 500°C for 3 hours. In the as-cast state, the thermal conductivity of the casting of Example 1 even reached 208.159 W / (mk), and the electrical conductivity of the casting reached 28.67 MS / m.

[0183] The alloys of Examples 1-5 were remelted and heat sinks of the same shape were prepared according to the die casting method described below, that is, the heat sink blanks with thinner heat dissipation fins (the shape is as shown in the attached figure). Figure 1 As shown in the figure), it is found that Examples 1-5 can form die castings with thin walls and high teeth well, as shown in the figure. Figure 1 , the heat sinks die-casted from the aluminum alloy prepared in Example 1 can be smoothly die-casted. It can be seen that the aluminum-iron-copper series high thermal conductivity die-cast aluminum alloy material prepared in the present invention has good die-casting performance.

[0184] The alloys of Examples 1-5 and Comparative Examples 1-7 were remelted, and die-casting specimens of the same specifications were prepared according to the die-casting method described below. The performance of the die-casting specimens after die-casting of the materials prepared in Examples 1-5 and the materials prepared in Comparative Examples 1-6 was tested, and the test results are shown in Table 1.

[0185] The die casting method is as follows:

[0186] (1) The aluminum melt temperature (remelting temperature) before die casting is 760℃.

[0187] (2) The die-cast aluminum liquid temperature is 722℃.

[0188] (3) Die casting mold temperature 205℃.

[0189] (4) Degas the aluminum melt with argon or nitrogen for 20-30 minutes before die casting. Remove slag after degassing.

[0190] (5) During the die-casting process, cold materials such as return materials are not added to the furnace to avoid contamination of the melt.

[0191] (6) Iron tools need to be coated and dried to prevent the aluminum melt from inhaling air during the die casting process.

[0192] Table 1

[0193]

[0194] As can be seen from Table 1, the aluminum-iron-copper series high thermal conductivity die-cast aluminum alloy material prepared by the present invention, and the aluminum alloy die-castings prepared therefrom have excellent thermal conductivity and electrical conductivity without heat treatment, and also have high heat resistance.

[0195] In Comparative Example 1, the iron content is low, the strength and hardness of the prepared aluminum alloy material decrease, and the heat resistance deteriorates.

[0196] In Comparative Example 2, the iron content is relatively high, and the electrical conductivity and thermal conductivity of the prepared aluminum alloy material decrease.

[0197] In Comparative Example 3, the copper content is low, resulting in reduced strength and hardness of the resulting aluminum alloy. Furthermore, a low copper content reduces the alloy's fluidity, hindering die-casting performance. In particular, when the copper content is less than 0.3, it has no effect on lowering the melting point and viscosity of the aluminum alloy, failing to improve the fluidity of the molten aluminum. This makes it difficult to die-cast thin-walled products.

[0198] In Comparative Example 4, the copper content is relatively high, the electrical conductivity and thermal conductivity are reduced, and the heat resistance is deteriorated.

[0199] In Comparative Example 5, no TCB was added, and the tensile strength, electrical conductivity and thermal conductivity decreased, and the heat resistance became worse.

[0200] In Comparative Example 6, 7% silicon was added, which exceeded the applicable control range of the model, resulting in decreased electrical conductivity and thermal conductivity, and poor heat resistance.

[0201] The die-cast samples of the materials prepared in Examples 1-5 and the material prepared in Comparative Example 7 were subjected to surface treatment after die-casting.

[0202] Treatment 1: Powder spraying treatment was performed on the surface of the die-casting (film thickness was 70-140 μm). The electrical conductivity of the die-casting samples of the alloy materials of Examples 1-5 after powder spraying treatment was measured to be greater than 26 MS / m; the electrical conductivity of the die-casting sample of the A380 aluminum alloy die-casting of Comparative Example 7 after powder spraying treatment was 15.64 MS / m.

[0203] Treatment 2: The die-castings were treated with chemical nickel (10 μm thick). The electrical conductivity of the die-castings made from the alloys of Examples 1-5 after chemical nickel treatment was greater than 25 MS / m. The electrical conductivity of the die-casting made from the A380 aluminum alloy of Comparative Example 7 after chemical nickel treatment was 14.03 MS / m.

[0204] It can be seen that the alloy material prepared by the present invention still maintains a high level of electrical conductivity after surface treatment, and exhibits significantly higher electrical conductivity than the existing A380 aluminum alloy material, thereby also having excellent thermal conductivity which is positively correlated with it.

[0205] In summary, it can be seen that the preparation method and formula of the aluminum-iron-copper high thermal conductivity die-cast aluminum alloy material prepared by the present invention are reasonable. Through a suitable preparation method and appropriate copper content and iron content, good die-casting performance, mechanical properties, electrical conductivity and heat resistance can be achieved, and there will be no negative impact on the thermal conductivity of the material, so that the alloy material can have a higher thermal conductivity.

[0206] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An aluminum-iron-copper series high thermal conductivity aluminum alloy material, characterized in that: The aluminum alloy material includes Si≤0.1% by mass percentage; Fe: 1.5-2.0%; Cu: 1-2.0%; Mn≤0.05%; Mg≤0.05%; Zn≤0.05%; Ti≤0.05%; Ni≤0.05%; TCB seed alloy addition amount: 0.1-0.6%; Sr: 0.0005-0.06%; Pb≤0.05%; Sn≤0.01%; Cd≤0.01%; each common impurity element ≤0.05%, the total impurity content ≤0.15%; the rest is Al; The main components and process conditions of the aluminum alloy material satisfy the following functional relationship: Y K =129.482+7.42a+31.505b+7.613c-46.378d <h2 style=";text-align:left;direction:ltr">Y<h2 style=";text-align:left;direction:ltr"> Q <h2 style=";text-align:left;direction:ltr"> =60.143+4.83a+14.983b–3.592c+125.73d <h2 style=";text-align:left;direction:ltr">Y<h2 style=";text-align:left;direction:ltr"> S <h2 style=";text-align:left;direction:ltr"> =19.538-3.303a–2.591b-3.304c+2.166d <h2 style=";text-align:left;direction:ltr">Y<h2 style=";text-align:left;direction:ltr"> Y <h2 style=";text-align:left;direction:ltr"> =26.542+5.911a+9.53b–6.96c+66.956d AND D =32.288–1.11a–2.174b+2.38c–3.207d Y R =8.013Y D –20.208 Wherein, a, b, c, and d represent the contents of Fe, Cu, TCB seeds, and Sr in the formula, respectively. K is the tensile strength of the die casting, Y Q is the yield strength of the die casting, Y S is the elongation of the die casting, Y Y is the hardness of the die casting, Y D is the electrical conductivity of the die casting, Y R Thermal conductivity of die castings; thermal conductivity of die castings ≥ 193.832W / mk, The preparation method of the iron-copper series high thermal conductivity aluminum alloy material comprises the following steps: S1. Add 85-90% of the total amount of aluminum ingots, melt and heat to 850-900℃, add iron agent in several times, let it stand after each addition, and then stir; S2. Add the preheated copper agent, let it stand for 10-20 minutes, and stir for 5-10 minutes; S3. Add the remaining aluminum ingots and adjust the aluminum liquid temperature to 740-760℃; S4. Use refining flux to refine, remove slag, and check for pinholes, which should reach level 1. When the aluminum liquid temperature is 720-750℃, add preheated TCB seeds; S5. Aluminum ingots are cast at a temperature of 720±10℃. During the casting process, argon or nitrogen is used to pass through a breathable brick with a pore size of 15-25μm to perform online degassing at the bottom of the filter box or launder, and ensure that the pinhole is no higher than level 2.

2. The aluminum-iron-copper series high thermal conductivity aluminum alloy material according to claim 1, characterized in that: The TCB seed crystal includes, by mass percentage, Ti: 1.8-2.2%, C: 0.28-0.35%, B: 0.28-0.35%, Mn: ≤0.1%, Fe: ≤0.3%, Si: ≤0.3%, V: ≤0.1%, and the rest is Al.

3. The aluminum-iron-copper series high thermal conductivity aluminum alloy material according to claim 1, characterized in that: The copper agent is red copper or Al-Cu master alloy.

4. The aluminum-iron-copper series high thermal conductivity aluminum alloy material according to claim 1, characterized in that: In step S4, the specific steps of refining with a refining agent are as follows: using argon or nitrogen as a carrier gas, adding a refining agent in an amount of 0.1-0.2% of the total amount of the aluminum liquid, and performing refining and purification; In step S4, the specific steps of slag removal are as follows: after refining and purification, the surface slag is removed for the first time, the aluminum liquid temperature is controlled at 740-760°C, and argon or nitrogen is used for degassing for 10-30 minutes before the second slag removal; In step S1, the iron agent is added in multiple times, and after each addition, the mixture is allowed to stand for 10-20 minutes and stirred for 5-10 minutes.

5. The die-casting method of the aluminum-iron-copper series high thermal conductivity aluminum alloy material according to any one of claims 1 to 4, characterized in that: The die-casting method comprises the following steps: (1) Aluminum melt temperature (remelting temperature) before die casting ≤ 760℃; (2) Die-cast aluminum liquid temperature 715±10℃; (3) Die casting mold temperature 200±10℃; (4) Degas the aluminum melt with argon or nitrogen for 20-30 minutes before die casting, and remove the slag after degassing; No cold material is added to the furnace during the die casting process; Iron tools used in the die casting process need to be coated and dried.

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