A low-eutectic Si-structured aluminum alloy and its preparation method

Abstract

This invention provides a low-eutectic Si-structured aluminum alloy and its preparation method, belonging to the technical field of aluminum alloy materials and their preparation. The low-eutectic Si-structured aluminum alloy is characterized by containing eleven elements: Si, Cu, Mg, Zn, Mn, Ti, Cr, Fe, B, Sr, and Al, and by mass percentage: Si: 0.3–0.4%, Cu: 1.0–4.3%, Mg: 0.8–1.0%, Zn: 0.0005–0.0015%, Mn: 0.07–0.09%, Ti: 0.12–0.17%, Cr: 0.04–0.05%, Fe: 0.42–0.45%, B: 0.025–0.035%, Sr: 0.07–0.09%, with the remainder being aluminum and unavoidable impurities. The low-eutectic Si-structured aluminum alloy and its preparation method of this invention produce a product with high strength, making it a preferred material for manufacturing conductive aluminum alloys, and offering significant social and economic benefits.

Description

Technical Field

[0001] This invention relates to a low-eutectic Si-structured aluminum alloy and its preparation method, belonging to the technical field of aluminum alloy materials and their preparation. Background Technology

[0002] Aluminum alloys are important materials for the aerospace industry due to their good corrosion resistance and low-temperature performance in environmental media, making them crucial for aircraft skins and liquid hydrogen and liquid oxygen containers. Because of their low cost, aluminum alloys are not only widely used in the military industry but also extensively employed in civilian applications, such as ship hulls, support structures, supporting facilities, pipes, valves, cylinder blocks, pumps, gearbox housings, and turbine blades.

[0003] The properties of aluminum alloys are generally closely related to their macrostructure. Most aluminum alloys have an Al matrix plus a eutectic silicon phase, with the ratio of Al matrix to eutectic silicon phase typically ranging from 5:5 to 6:4. Aluminum alloys with ratios lower than this range exhibit certain differences in structure and properties compared to traditional aluminum alloys. Preparing novel low-eutectic Si microstructure aluminum alloys will further enrich the microstructure characteristics of aluminum alloys and is of great significance for the development of new aluminum alloys.

[0004] CN114540672A discloses a high-strength, high-thermal-conductivity AlSi aluminum alloy and its preparation method. The specific steps of the method are as follows: the following elements are prepared by mass percentage: Cu 0.15%-0.65%, Si 8.5%-11.5%, Mn 0.35%-0.55%, Mg 0.3%-0.55%, Fe≤0.25%, Zn≤0.15%, Ca≤20ppm, P≤20ppm, Sr 0.010%-0.035%, B 0.0045%-0.01%, La+Ce 0.015%-0.035%, with the balance being Al and impurities, wherein the total impurity content is not greater than 0.15%, thus obtaining the high-strength, high-thermal-conductivity AlSi aluminum alloy. The method has the following drawbacks: the aluminum alloy structure obtained by this method is an Al matrix + eutectic silicon phase, with a ratio of about 6:4. Although the strength of the aluminum alloy is improved compared with the previous method, the material strength is still insufficient.

[0005] CN107385289A discloses a high-strength, high-toughness, corrosion-resistant hypoeutectic Al-Si cast aluminum alloy with Zr and Sr composite microalloying and its preparation method. The specific steps of the method are as follows: The aluminum alloy is mainly composed of aluminum (Al), silicon (Si), zirconium (Zr), strontium (Sr) and iron (Fe). The preparation method includes the following steps: (1) First, the furnace temperature is raised to 850±10℃, pure Al and Al-Si intermediate alloy are added, and after they are completely melted, the intermediate alloy is added in sequence; (2) Second, after all the intermediate alloy and metal are melted, the temperature is adjusted to 750±10℃, hexachloroethane is added for refining and degassing until no gas escapes, and after standing and holding for 5 to 10 minutes, the slag is removed and the alloy is poured into a metal mold preheated to 300±10℃ to be cast into an ingot, thus obtaining a high-strength, high-toughness, corrosion-resistant hypoeutectic Al-Si cast aluminum alloy with Zr and Sr composite microalloying. The method has the following drawbacks: the aluminum alloy structure obtained by this method is an Al matrix + eutectic silicon phase, with a ratio of about 5:5. Although the strength of the aluminum alloy obtained is improved compared with the previous method, the material strength is still insufficient. Summary of the Invention

[0006] The first technical problem solved by this invention is to provide an aluminum alloy with a low eutectic Si structure.

[0007] A low-eutectic Si-structured aluminum alloy, characterized in that it contains eleven elements: Si, Cu, Mg, Zn, Mn, Ti, Cr, Fe, B, Sr, and Al, and by mass percentage: Si: 0.3–0.4%, Cu: 1.0–4.3%, Mg: 0.8–1.0%, Zn: 0.0005–0.0015%, Mn: 0.07–0.09%, Ti: 0.12–0.17%, Cr: 0.04–0.05%, Fe: 0.42–0.45%, B: 0.025–0.035%, Sr: 0.07–0.09%, with the remainder being aluminum and unavoidable impurities.

[0008] Preferably, a low-eutectic Si-structured aluminum alloy is characterized by comprising eleven elements: Si, Cu, Mg, Zn, Mn, Ti, Cr, Fe, B, Sr, and Al, wherein by mass percentage: Si: 0.360–0.367%, Cu: 3.1–4.2%, Mg: 0.80–0.95%, Zn: 0.0008–0.0012%, Mn: 0.075–0.080%, Ti: 0.150–0.165%, Cr: 0.045–0.049%, Fe: 0.422–0.440%, B: 0.028–0.031%, Sr: 0.08–0.09%, with the remainder being aluminum and unavoidable impurities.

[0009] More preferably, a low-eutectic Si-structured aluminum alloy is characterized by containing eleven elements: Si, Cu, Mg, Zn, Mn, Ti, Cr, Fe, B, Sr, and Al, and by mass percentage: Si: 0.362–0.366%, Cu: 3.19–4.16%, Mg: 0.88–0.90%, Zn: 0.0010–0.0011%, Mn: 0.0780–0.0795%, Ti: 0.159–0.163%, Cr: 0.0465–0.0472%, Fe: 0.424–0.435%, B: 0.029–0.030%, Sr: 0.082–0.086%, with the remainder being aluminum and unavoidable impurities.

[0010] The low-eutectic Si-structured aluminum alloy is composed of an Al matrix and a eutectic silicon phase, with a volume ratio of 7-8:2-3.

[0011] The low-eutectic Si-structured aluminum alloy comprises an FCC aluminum matrix and an FCC (Al) matrix. 0.5 Fe3Si 0.5 ), cF12(Mg2Si), tP4(Cu 0.9 Fe 0.1 Ti), tl32(Fe 3.5 B) Precipitation strengthening phases with cP2O (AlCu4) and tP4 (CuTi) as the main components.

[0012] The second technical problem solved by this invention is to provide a method for preparing a low-eutectic Si-structured aluminum alloy, comprising the following steps:

[0013] a. Based on the mass percentage of low eutectic Si aluminum alloy, take metal raw materials with a purity ≥99.95% and a particle size of 1-5mm respectively;

[0014] b. Melting: Pour the Al particles obtained in step a into a melting furnace and heat them to melt. The melting temperature is 690℃~720℃. After they are in a liquid state, raise the temperature to 760℃~780℃ and add Cu, Si and other metal particles and Al5Ti1B master alloy in sequence. After they are completely melted, stir them evenly. Keep the temperature constant during the stirring process.

[0015] c. Slag and gas removal: Keep the furnace temperature constant at 730-760℃, introduce high-purity argon gas and stir for 8-10 minutes; remove the slag, preheat the mold at 80-150℃ for 5-10 minutes, and then pour.

[0016] d. Homogenization treatment: Place the sample in a heat treatment furnace, set the temperature to 450-480℃, and hold for 180-240 minutes. Remove the sample and quench it in water.

[0017] e. Artificial aging treatment: Place the sample obtained in step d into a heat treatment furnace, set the temperature to 160-200℃, hold for 600-1000 minutes, cool with the furnace, take out and cut the sample, and perform characterization tests.

[0018] In step b, the time for stirring after complete melting is 10 to 30 minutes.

[0019] In step c, the argon flow rate is 10-40 L / min, and the argon pressure is controlled at 0.1-0.8 MPa.

[0020] Beneficial effects of this invention:

[0021] 1. The present invention provides a low eutectic Si structure aluminum alloy and its preparation method. The low eutectic Si structure aluminum alloy obtained has high strength. The structure is composed of Al matrix + eutectic silicon phase in a ratio of (7-8):(2-3). Solid solution strengthening and precipitation phase strengthening cooperate with each other to improve the strength of the material.

[0022] 2. The present invention provides a low eutectic Si structure aluminum alloy and its preparation method. The low eutectic Si structure aluminum alloy obtained has high corrosion resistance. Electrochemical test results show that the corrosion current is basically the same as that of the commercially available 6061 aluminum alloy. It can be used as a corrosion-resistant material or coating for equipment.

[0023] 3. The low eutectic Si structure aluminum alloy and its preparation method provided by the present invention have a low eutectic Si structure aluminum alloy with electrical conductivity twice that of commercially available 6061 aluminum alloy, and can be used as a preferred material for making conductive aluminum alloys.

[0024] 4. The low eutectic Si structure aluminum alloy and its preparation method provided by the present invention adopt graphite crucible + induction heating melting, using existing market equipment and crucibles, the melting time can be completed within 30 minutes, with low energy consumption, low cost, simple process operation, and can realize the production of large-size aluminum alloy ingots, which is suitable for industrial production and has good economic benefits. Attached Figure Description

[0025] Figure 1 This is a metallographic diagram of the low eutectic Si structure aluminum alloy obtained in this invention.

[0026] Figure 2 The X-ray diffraction pattern of the low eutectic Si aluminum alloy obtained in this invention.

[0027] Figure 3 Electrochemical test curves of the low eutectic Si structure aluminum alloy obtained in this invention.

[0028] Figure 4 This is a schematic diagram of backscattered electron imaging of the low eutectic Si structure aluminum alloy obtained in this invention. Detailed Implementation

[0029] The embodiments of the present invention will be described in detail below with reference to specific examples. However, those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the embodiments, conventional conditions apply.

[0030] Example 1

[0031] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.374%, Cu 1.245%, Mg 0.913%, Zn 0.001%, Mn 0.082%, Ti 0.165%, Cr 0.048%, Fe 0.439%, Al 96.616%, B 0.030%, Sr 0.086%, with the balance being impurities, the content of which is not greater than 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 168.2 MPa at room temperature in the as-cast state.

[0032] Prepare the raw materials according to the above aluminum alloy material formula;

[0033] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0034] Degassing: The furnace temperature is kept constant at 750℃, high-purity argon gas is introduced and stirred to degas, and the process is maintained for 10 minutes; the argon gas flow rate is 10L / min, and the argon gas pressure is controlled at 0.2MPa;

[0035] Remove the slag, preheat the casting mold at 80℃ for 5 minutes, and then pour the casting.

[0036] The samples were cut and characterized, and the results are shown in Table 1.

[0037] Example 2

[0038] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.374%, Cu 1.245%, Mg 0.913%, Zn 0.001%, Mn 0.082%, Ti 0.165%, Cr 0.048%, Fe 0.439%, Al 96.616%, B 0.030%, Sr 0.086%, with the balance being impurities, the content of which is not greater than 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 230.7 MPa at room temperature after heat treatment.

[0039] Prepare the raw materials according to the above aluminum alloy material formula;

[0040] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0041] Degassing: The furnace temperature is kept constant at 750℃, high-purity argon gas is introduced and stirred to degas, and the process is maintained for 10 minutes; the argon gas flow rate is 10L / min, and the argon gas pressure is controlled at 0.2MPa;

[0042] Remove the slag, preheat the casting mold at 80℃ for 5 minutes, and then pour the casting.

[0043] Homogenization treatment: Place the sample in a heat treatment furnace, set the temperature to 470℃, and hold for 180 minutes. Remove the sample and quench it in water.

[0044] Artificial aging treatment: The above samples were placed in a heat treatment furnace, the temperature was set to 180℃, the holding time was 600 minutes, and the samples were cooled with the furnace. The samples were then removed and cut for characterization tests. The results are shown in Table 1.

[0045] Example 3

[0046] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.374%, Cu 1.245%, Mg 0.913%, Zn 0.001%, Mn 0.082%, Ti 0.165%, Cr 0.048%, Fe 0.439%, Al 96.616%, B 0.030%, Sr 0.086%, with the balance being impurities, the content of which is not greater than 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 185.9 MPa at room temperature after heat treatment.

[0047] Prepare the raw materials according to the above aluminum alloy material formula;

[0048] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0049] Slag and gas were removed, and the furnace temperature was kept constant at 750℃. High-purity argon gas was introduced and stirred for 10 minutes. The argon gas flow rate was 10L / min, and the argon gas pressure was controlled at 0.2MPa.

[0050] Remove the scum, preheat the mold at 80℃ for 5 minutes, and then pour the casting.

[0051] Homogenization treatment: Place the sample in a heat treatment furnace, set the temperature to 550℃, hold for 180 minutes, remove the sample, and quench it in water.

[0052] Artificial aging treatment: The above samples were placed in a heat treatment furnace, the temperature was set to 180℃, the holding time was 600 minutes, and the samples were cooled with the furnace. The samples were then removed and cut for characterization tests. The results are shown in Table 1.

[0053] Example 4

[0054] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.370%, Cu 2.234%, Mg 0.904%, Zn 0.001%, Mn 0.081%, Ti 0.164%, Cr 0.047%, Fe 0.435%, Al 95.649%, B 0.030%, Sr 0.086%, with the balance being impurities, the content of which is not greater than 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 182.4 MPa at room temperature after heat treatment.

[0055] Prepare the raw materials according to the above aluminum alloy material formula;

[0056] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0057] Degassing: The furnace temperature is kept constant at 750℃, high-purity argon gas is introduced and stirred to degas, and the process is maintained for 10 minutes; the argon gas flow rate is 10L / min, and the argon gas pressure is controlled at 0.2MPa;

[0058] Remove the slag, preheat the casting mold at 80℃ for 5 minutes, and then pour the casting.

[0059] The samples were cut and characterized, and the results are shown in Table 1.

[0060] Example 5

[0061] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.370%, Cu 2.234%, Mg 0.904%, Zn 0.001%, Mn 0.081%, Ti 0.164%, Cr 0.047%, Fe 0.435%, Al 95.649%, B 0.030%, Sr 0.086%, with the balance being impurities with a content not exceeding 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 262.7 MPa at room temperature after heat treatment.

[0062] Prepare the raw materials according to the above aluminum alloy material formula;

[0063] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0064] Slag and gas were removed, and the furnace temperature was kept constant at 750℃. High-purity argon gas was introduced and stirred for 10 minutes. The argon gas flow rate was 10L / min, and the argon gas pressure was controlled at 0.2MPa.

[0065] Remove the scum, preheat the mold at 80℃ for 5 minutes, and then pour the casting.

[0066] Homogenization treatment: Place the sample in a heat treatment furnace, set the temperature to 470℃, and hold for 180 minutes. Remove the sample and quench it in water.

[0067] Artificial aging treatment: The above samples were placed in a heat treatment furnace, the temperature was set to 180℃, the holding time was 600 minutes, and the samples were cooled with the furnace. The samples were then removed and cut for characterization tests. The results are shown in Table 1.

[0068] Example 6

[0069] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.370%, Cu 2.234%, Mg 0.904%, Zn 0.001%, Mn 0.081%, Ti 0.164%, Cr 0.047%, Fe 0.435%, Al 95.649%, B 0.030%, Sr 0.086%, with the balance being impurities with a content not exceeding 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 194.6 MPa at room temperature after heat treatment.

[0070] Prepare the raw materials according to the above aluminum alloy material formula;

[0071] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0072] Slag and gas were removed, and the furnace temperature was kept constant at 750℃. High-purity argon gas was introduced and stirred for 10 minutes. The argon gas flow rate was 10L / min, and the argon gas pressure was controlled at 0.2MPa.

[0073] Remove the scum, preheat the mold at 80℃ for 5 minutes, and then pour the casting.

[0074] Homogenization treatment: Place the sample in a heat treatment furnace, set the temperature to 550℃, hold for 180 minutes, remove the sample, and quench it in water.

[0075] Artificial aging treatment: The above samples were placed in a heat treatment furnace, the temperature was set to 180℃, the holding time was 600 minutes, and the samples were cooled with the furnace. The samples were then removed and cut for characterization tests. The results are shown in Table 1.

[0076] Example 7

[0077] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.366%, Cu 3.191%, Mg 0.895%, Zn 0.001%, Mn 0.080%, Ti 0.162%, Cr 0.047%, Fe 0.431%, Al 94.712%, B 0.030%, Sr 0.085%, with the balance being impurities with a content not exceeding 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 194.0 MPa at room temperature after heat treatment.

[0078] Prepare the raw materials according to the above aluminum alloy material formula;

[0079] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0080] Degassing: The furnace temperature is kept constant at 750℃, high-purity argon gas is introduced and stirred to degas, and the process is maintained for 10 minutes; the argon gas flow rate is 10L / min, and the argon gas pressure is controlled at 0.2MPa;

[0081] Remove the slag, preheat the casting mold at 80℃ for 5 minutes, and then pour the casting.

[0082] The samples were cut and characterized, and the results are shown in Table 1.

[0083] Example 8

[0084] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.366%, Cu 3.191%, Mg 0.895%, Zn 0.001%, Mn 0.080%, Ti 0.162%, Cr 0.047%, Fe 0.431%, Al 94.712%, B 0.030%, Sr 0.085%, with the balance being impurities with a content not exceeding 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 263.1 MPa at room temperature after heat treatment.

[0085] Prepare the raw materials according to the above aluminum alloy material formula;

[0086] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0087] Slag and gas were removed, and the furnace temperature was kept constant at 750℃. High-purity argon gas was introduced and stirred for 10 minutes. The argon gas flow rate was 10L / min, and the argon gas pressure was controlled at 0.2MPa.

[0088] Remove the scum, preheat the mold at 80℃ for 5 minutes, and then pour the casting.

[0089] Homogenization treatment: Place the sample in a heat treatment furnace, set the temperature to 470℃, and hold for 180 minutes. Remove the sample and quench it in water.

[0090] Artificial aging treatment: The above samples were placed in a heat treatment furnace, the temperature was set to 180℃, the holding time was 600 minutes, and the samples were cooled with the furnace. The samples were then removed and cut for characterization tests. The results are shown in Table 1.

[0091] Test results showed that the sample obtained in Example 8 had superior performance. The samples in this group of cases were characterized by optical microscopy, XRD, and backscattered electron imaging. Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown.

[0092] The low-eutectic Si-structured aluminum alloy prepared in Example 8 formed face-centered cubic FCCs, each characterized primarily by Al, corresponding to five peaks at 38°, 45°, 65°, 78°, and 82° in the XRD pattern. Simultaneously, FCC(Al) was formed. 0.5 Fe3Si 0.5 ), cF12(Mg2Si), tP4(Cu 0.9 Fe 0.1 Ti), tl32(Fe 3.5 B) Precipitation strengthening phases, mainly composed of cP2O (AlCu4) and tP4 (CuTi), are located in the Al matrix and at grain boundaries, achieving excellent solid solution and precipitation strengthening effects. Metallographic diagrams show that the low-eutectic Si aluminum alloy consists of an Al matrix and eutectic silicon phases in a ratio of approximately 7:2, lower than the 5:5 ratio in traditional aluminum-silicon alloys. Backscattered imagery from Example 8 further confirms the relatively small proportion of the eutectic silicon phase.

[0093] The electrochemical corrosion characteristics of the low eutectic Si aluminum alloy of Example 8 were tested using a 3.0% NaCl solution as the etchant, with commercially available 6061 as the control group. The polarization curves are shown below. Figure 3 As shown. See also Figure 3 The values ​​indicated are the electrochemical properties of the low-eutectic Si aluminum alloy of Example 8 and the commercially available 6061 aluminum alloy. The corrosion current densities of the low-eutectic Si aluminum alloy of Example 8 and the commercially available 6061 aluminum alloy reached 1.31E-07 A / cm², respectively. 2 and 1.02E-07A / cm 2 The corrosion potentials reached -0.615V and -0.711V, respectively. Therefore, the low-eutectic Si aluminum alloy of Example 8 exhibited good corrosion resistance. The electrical conductivity of the prepared low-eutectic Si aluminum alloy was measured using an RTS-8 four-probe tester, comparing it to commercially available 6061. The results showed that the electrical conductivity of the low-eutectic Si aluminum alloy of Example 8 was twice that of the commercially available 6061 aluminum alloy, making it a preferred material for manufacturing conductive aluminum alloys.

[0094] Example 9

[0095] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.366%, Cu 3.191%, Mg 0.895%, Zn 0.001%, Mn 0.080%, Ti 0.162%, Cr 0.047%, Fe 0.431%, Al 94.712%, B 0.030%, Sr 0.085%, with the balance being impurities, the content of which is not greater than 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 222.3 MPa at room temperature after heat treatment.

[0096] Prepare the raw materials according to the above aluminum alloy material formula;

[0097] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0098] Slag and gas were removed, and the furnace temperature was kept constant at 750℃. High-purity argon gas was introduced and stirred for 10 minutes. The argon gas flow rate was 10L / min, and the argon gas pressure was controlled at 0.2MPa.

[0099] Remove the scum, preheat the mold at 80℃ for 5 minutes, and then pour the casting.

[0100] Homogenization treatment: Place the sample in a heat treatment furnace, set the temperature to 550℃, hold for 180 minutes, remove the sample, and quench it in water.

[0101] Artificial aging treatment: The above samples were placed in a heat treatment furnace, the temperature was set to 180℃, the holding time was 600 minutes, and the samples were cooled with the furnace. The samples were then removed and cut for characterization tests. The results are shown in Table 1.

[0102] Example 10

[0103] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.363%, Cu 4.154%, Mg 0.886%, Zn 0.001%, Mn 0.079%, Ti 0.160%, Cr 0.046%, Fe 0.426%, Al 93.771%, B 0.029%, Sr 0.084%, with the balance being impurities with a content not exceeding 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 151.3 MPa at room temperature after heat treatment.

[0104] Prepare the raw materials according to the above aluminum alloy material formula;

[0105] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0106] Degassing: The furnace temperature is kept constant at 750℃, high-purity argon gas is introduced and stirred to degas, and the process is maintained for 10 minutes; the argon gas flow rate is 10L / min, and the argon gas pressure is controlled at 0.2MPa;

[0107] Remove the slag, preheat the casting mold at 80℃ for 5 minutes, and then pour the casting.

[0108] The samples were cut and characterized, and the results are shown in Table 1.

[0109] Example 11

[0110] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.363%, Cu 4.154%, Mg 0.886%, Zn 0.001%, Mn 0.079%, Ti 0.160%, Cr 0.046%, Fe 0.426%, Al 93.771%, B 0.029%, Sr 0.084%, with the balance being impurities, the content of which is not greater than 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 243.8 MPa at room temperature after heat treatment.

[0111] Prepare the raw materials according to the above aluminum alloy material formula;

[0112] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0113] Slag and gas were removed, and the furnace temperature was kept constant at 750℃. High-purity argon gas was introduced and stirred for 10 minutes. The argon gas flow rate was 10L / min, and the argon gas pressure was controlled at 0.2MPa.

[0114] Remove the scum, preheat the mold at 80℃ for 5 minutes, and then pour the casting.

[0115] Homogenization treatment: Place the sample in a heat treatment furnace, set the temperature to 470℃, and hold for 180 minutes. Remove the sample and quench it in water.

[0116] Artificial aging treatment: The above samples were placed in a heat treatment furnace, the temperature was set to 180℃, the holding time was 600 minutes, and the samples were cooled with the furnace. The samples were then removed and cut for characterization tests. The results are shown in Table 1.

[0117] Example 12

[0118] A low-eutectic Si-structured aluminum alloy comprises the following elements in mass percentage: Si 0.363%, Cu 4.154%, Mg 0.886%, Zn 0.001%, Mn 0.079%, Ti 0.160%, Cr 0.046%, Fe 0.426%, Al 93.771%, B 0.029%, Sr 0.084%, with the balance being impurities, the content of which is not greater than 0.08%. The low-eutectic Si-structured aluminum alloy has a tensile strength of 244.7 MPa at room temperature after heat treatment.

[0119] Prepare the raw materials according to the above aluminum alloy material formula;

[0120] Melting: Pour the Al material from the above steps into a melting furnace and heat it to melt. The melting temperature is 690℃-720℃. After the aluminum liquid is formed, raise the temperature to 760℃-780℃. Add Cu, Si and other alloy raw materials and intermediate alloys in sequence. After complete melting, stir for 20 minutes. Keep the temperature constant during the stirring process.

[0121] Slag and gas were removed, and the furnace temperature was kept constant at 750℃. High-purity argon gas was introduced and stirred for 10 minutes. The argon gas flow rate was 10L / min, and the argon gas pressure was controlled at 0.2MPa.

[0122] Remove the scum, preheat the mold at 80℃ for 5 minutes, and then pour the casting.

[0123] Homogenization treatment: Place the sample in a heat treatment furnace, set the temperature to 550℃, hold for 180 minutes, remove the sample, and quench it in water.

[0124] Artificial aging treatment: The above samples were placed in a heat treatment furnace, the temperature was set to 180℃, the holding time was 600 minutes, and the samples were cooled with the furnace. The samples were then removed and cut for characterization tests. The results are shown in Table 1.

[0125] Table 1. Resistivity, conductivity, corrosion voltage, and corrosion current measurements of the low eutectic Si structure aluminum alloy examples of the present invention.

[0126]

[0127] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading the specification of the present invention, those skilled in the art may make some modifications or improvements based on the present invention, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A hypoeutectic Si microstructure aluminum alloy, characterized by: Si: 0.3-0.4%, Cu: 1.0-4.3%, Mg: 0.8-1.0%, Zn: 0.0005-0.0015%, Mn: 0.07-0.09%, Ti: 0.12-0.17%, Cr: 0.04-0.05%, Fe: 0.42-0.45%, B: 0.025-0.035%, Sr: 0.07-0.09%, the rest being aluminum and inevitable impurities.

2. The hypoeutectic Si microstructure aluminum alloy according to claim 1, characterized in that: Si: 0.360-0.367%, Cu: 3.1-4.2%, Mg: 0.80-0.95%, Zn: 0.0008-0.0012%, Mn: 0.075-0.080%, Ti: 0.150-0.165%, Cr: 0.045-0.049%, Fe: 0.422-0.440%, B: 0.028-0.031%, Sr: 0.08-0.09%, the rest being aluminum and inevitable impurities.

3. The low eutectic Si microstructure aluminum alloy according to claim 1, characterized in that: Si: 0.362-0.366%, Cu: 3.19-4.16%, Mg: 0.88-0.90%, Zn: 0.0010-0.0011%, Mn: 0.0780-0.0795%, Ti: 0.159-0.163%, Cr: 0.0465-0.0472%, Fe: 0.424-0.435%, B: 0.029-0.030%, Sr: 0.082-0.086%, the rest being aluminum and inevitable impurities.

4. A hypoeutectic Si microstructure aluminum alloy according to any one of claims 1-3, characterized in that: The hypoeutectic Si structure aluminum alloy is composed of an Al matrix and eutectic silicon phases, and the volume ratio is 7-8:2-3.

5. A hypoeutectic Si microstructured aluminium alloy according to any of claims 1-3, c h a ra cte ri zed i n that: The hypoeutectic Si-organised aluminium alloy comprises an FCC aluminium matrix, and precipitate strengthening phases of FCC (Al 0.5 Fe3Si 0.5 ), cF12 (Mg2Si), tP4 (Cu 0.9 Fe 0.1 Ti), tl32 (Fe 3.5 B), cP20 (AlCu4), tP4 (CuTi) as main components.

6. A method of producing a hypoeutectic Si microstructure aluminium alloy according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: a. According to the mass percentage of the hypoeutectic Si structure aluminum alloy, metal raw materials with a purity of ≥99.95% and a particle size of 1-5 mm are taken respectively; b. Melting: pour the Al particles obtained in step a into a melting furnace and heat to melt, the melting temperature is 690-720°C, after forming a liquid state, the temperature is increased to 760-780°C, and then Cu, Si and other metal particles and Al5Ti1B and other intermediate alloys are added in sequence, after complete melting, uniform stirring is performed, and the temperature is kept unchanged during the stirring process; c. Deslagging and degassing: keep the furnace temperature at 730-760°C, pass high-purity argon gas and stir for 8-10 min; remove the floating dross, preheat the mold at 80-150°C for 5-10 min, and then pour; d. Homogenization treatment: place the sample in a heat treatment furnace, set the temperature to 450-480°C, and keep the temperature for 180-240 min, then take out the sample and perform water quenching. e. Artificial aging treatment: the sample obtained in step d is placed in a heat treatment furnace, the temperature is set to 160-200 DEG C, the holding time is 600-1000 minutes, the furnace is cooled, the sample is taken out and cut, and the characterization test is carried out.

7. The method of claim 6, wherein the low eutectic Si microstructure aluminum alloy is prepared by the following steps: The argon flow in step c is 10-40 L / min, and the argon pressure is controlled at 0.1-0.8 MPa. ​

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