A high silicon aluminum alloy material and preparation method thereof

Abstract

The present invention belongs to the technical field of preparation of non-ferrous metal materials, and particularly relates to a high-silicon aluminum alloy material and a preparation method thereof. The high-silicon aluminum alloy material comprises the following raw material components in mass percentage: Si: 12-14%, Cu: 1.6-2.0%, Mg: 1.0-2.0%, Ni: 0.5-1.3%, Ti≤0.05%, Sc: 0.1-0.3%, Sr: 0.04-0.07%, and the balance is Al; the Cu / Sc ratio is 6-16:1; and the present invention simultaneously improves the tensile strength, yield strength, and elongation of the aluminum alloy material.

Description

Technical Field

[0001] The present invention belongs to the technical field of nonferrous metal material preparation, and in particular relates to a high-silicon aluminum alloy material and a preparation method thereof. Background Art

[0002] High-silicon aluminum alloy is an alloy material with aluminum and silicon as the main components, and its silicon content is usually between 12% and 25%. It has high strength, high hardness and wear resistance, and can withstand large loads; it can still maintain stability in high temperature and corrosive environments, and its oxidation resistance is better than that of ordinary aluminum alloys; it has excellent thermal conductivity and is suitable for scenarios such as electronic component radiators. It has a low melting point and is easy to cast and process into parts with complex shapes. After extrusion molding, high-silicon aluminum alloy is widely used in wear-resistant parts such as automotive engine pistons and cylinder liners, aerospace hydraulic valve bodies and satellite structural parts, electronic heat dissipation substrates and packaging shells, industrial robot joint components, and new energy battery trays and other key areas due to its high strength, wear resistance and lightweight properties.

[0003] The composition design of aluminum-silicon alloys is particularly important. The silicon content must be precisely balanced. Too high a silicon content can easily form coarse primary silicon, causing stress concentration and brittle fracture, while too low a silicon content can weaken wear resistance. Rare earth elements can play an auxiliary role in the modification of aluminum-silicon alloys, while improving the structure and refining the grains. However, the ratio of rare earth elements to other strengthening elements must take into account the synergistic strengthening and uniform distribution of the precipitated phases to prevent interphase competition or abnormal coarsening caused by imbalanced proportions. In addition, the stability of active elements must be guaranteed through process adaptation to avoid melting losses and deterioration failure.

[0004] Authorization announcement number CN108251710B discloses a high-strength, high-toughness, high-silicon aluminum alloy suitable for squeeze casting and its preparation process. The components, by weight percentage, are: 17-23% Si, 0.5-1% Cu, 0.3-0.8% Mg, 0.2-0.5% Fe, 0.5-0.8% Mn, 0.2-0.4% RE, 0.05-0.1% P, 0.3% trace elements, and the balance is Al; the trace elements include Cr or Ti; the tensile strength is greater than 350 MPa, the yield strength is greater than 160 MPa, and the elongation is greater than 3%. The performance needs to be further improved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a high-silicon aluminum alloy material and a preparation method thereof, while improving the tensile strength, yield strength and elongation of the aluminum alloy material.

[0006] An embodiment of the present invention provides a high-silicon aluminum alloy material, comprising the following raw material components in percentage by mass:

[0007] Si: 12-14%, Cu: 1.6-2.0%, Mg: 1.0-2.0%, Ni: 0.5-1.3%, Ti≤0.05%, Sc: 0.1-0.3%, Sr: 0.04-0.07%, and the balance is Al; the Cu / Sc ratio is 6-16:1.

[0008] Preferably, the raw material components include the following weight percentages:

[0009] Si: 12.5-13.5%, Cu: 1.6-2.0%, Mg: 1.3-1.7%, Ni: 0.7-1.2%, Ti: 0.02-0.04%, Sc: 0.13-0.25%, Sr: 0.05-0.065%, and the balance is Al; the Cu / Sc ratio is 8-13:1.

[0010] More preferably, the raw material components include the following weight percentages:

[0011] Si: 12.8%, Cu: 1.7%, Mg: 1.5%, Ni: 0.9%, Ti: 0.03%, Sc: 0.14%, Sr: 0.055%, and the balance is Al.

[0012] An embodiment of the present invention provides a method for preparing the high-silicon aluminum alloy material, comprising the following steps: mixing the raw material components of the high-silicon aluminum alloy material, smelting, refining, online processing, semi-continuous casting, homogenization treatment, extrusion molding, solid solution and aging treatment to obtain the high-silicon aluminum alloy material.

[0013] Optionally, during smelting, the temperature is 730-750° C., the oxygen content is controlled below 300 ppm, and an inert gas is introduced above the melt.

[0014] Optionally, during online processing, the degassing gas is argon, the argon flow rate is 30-50 L / min, the rotation speed is 300-450 r / min, Al-5Ti-B is used for wire feeding, and the wire feeding ratio is 1.5 kg / 1 tAl; the filtration method adopts plate filtration.

[0015] Optionally, during semi-continuous casting, the casting end temperature is controlled at 680-690°C, the steady-state casting speed is 50-55 mm / min, and the water flow rate is 16-20 m 3 / h.

[0016] Optionally, during the homogenization treatment, the heating rate is controlled to be 50-60°C / h, the homogenization temperature is 490-500°C, and the holding time is 14-18h.

[0017] Optionally, during extrusion molding, the extrusion temperature is controlled to be 370-410° C. and the extrusion speed is controlled to be 0.1-0.3 m / min.

[0018] Optionally, the solution treatment temperature is 505-515°C, and the holding time is 20-40 minutes; the aging treatment temperature is 155-165°C, and the holding time is 2-4 hours.

[0019] The beneficial effect of the present invention is that, based on the traditional 4 series alloy, the present invention limits the silicon content and copper content, and at the same time limits the Cu / Sc content ratio to optimize the alloy structure and performance. The precipitated phase (θ' phase) hinders dislocation motion, while Sc forms a thermally stable phase, preferentially nucleates heterogeneously at grain boundaries and defects, refines grains (Hall-Petch effect) and acts as The appropriate Cu / Sc ratio ensures that Sc atoms preferentially occupy defect sites, avoiding competition with Cu to form coarse composite phases, while optimizing precipitation kinetics: Precipitation occurs first during the low-temperature aging stage, providing a foundation for subsequent It provides nucleation sites, forming coherent / semi-coherent interfaces that synergistically strengthen the matrix. Simultaneously, melt modification is performed under inert gas protection to effectively reduce oxidation and burnout of alloying elements (such as magnesium and strontium), ensuring that the modifier (strontium) can fully function, while also preventing the formation of oxide inclusions and purifying the matrix structure. DETAILED DESCRIPTION Example 1

[0020] A method for preparing a high-silicon aluminum alloy material, wherein the ingredients are composed of the following components by weight percentage: Si: 12.8%, Cu: 1.7%, Mg: 1.5%, Ni: 0.9%, Ti: 0.03%, Sc: 0.14%, Sr: 0.055%, and the balance is Al and unavoidable impurities. The specific steps are:

[0021] The first step is to calculate and prepare the ingredients according to the designed composition requirements, preheat the furnace to above 650℃ in advance, put 99.70% aluminum ingots, aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-nickel master alloy, and aluminum-scandium master alloy into the melting furnace, and set the melting furnace to 740℃ for heating and melting. After it is fully melted, introduce inert gas Ar above the melt in the furnace, and control the oxygen content at 200ppm. Add aluminum-titanium master alloy and aluminum-strontium master alloy, and then use the rotor in the furnace to degas and refine the aluminum melt. The refining time is 25min, the rotor speed is 450r / min, and the argon flow rate is 50L / min. After degassing is completed, let it stand for 10min to skim off the slag. After skimming off the slag, the temperature of the aluminum melt is adjusted to 730℃ and let it stand for 30min.

[0022] The second step is online processing. The online degassing gas is argon, the argon flow rate is 40L / min, and the rotor speed is 350r / min. Online grain refinement uses Al-5Ti-B for wire feeding, and the wire feeding ratio is 1.5kg / 1tAl. The filtration method uses plate filtration, 30PPi+50PPi.

[0023] The third step is to use oil-lubricated tooling for semi-continuous casting. The semi-continuous casting parameters are: casting end temperature 680-690℃, steady-state casting speed 52mm / min, water flow 18m 3 / h.

[0024] The fourth step is homogenization treatment, with a heating rate of 60℃ / h, a homogenization temperature of 495±5℃, a holding time of 16h after reaching the temperature, and a cooling method of air cooling + water mist cooling after reaching the temperature.

[0025] The fifth step is extrusion molding, the extrusion temperature is 385°C, and the extrusion speed is 0.15m / min.

[0026] The sixth step is solution aging treatment, solution temperature 510℃, holding time 30min, aging temperature 160℃, holding time 2.5h. Example 2

[0027] A method for preparing a high-silicon aluminum alloy material, wherein the ingredients are composed of the following components by weight percentage: Si: 13.2%, Cu: 1.8%, Mg: 1.6%, Ni: 0.10%, Ti: 0.03%, Sc: 0.20%, Sr: 0.06%, and the balance is Al and unavoidable impurities. The specific steps are:

[0028] The first step is to calculate and prepare the ingredients according to the designed composition requirements, preheat the furnace to above 650℃ in advance, put 99.70% aluminum ingots, aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-nickel master alloy, and aluminum-scandium master alloy into the melting furnace, and set the melting furnace to 740℃ for heating and melting. After it is fully melted, introduce inert gas Ar above the melt in the furnace, and control the oxygen content at 260ppm. Add aluminum-titanium master alloy and aluminum-strontium master alloy, and then use the rotor in the furnace to degas and refine the aluminum melt. The refining time is 20min, the rotor speed is 480r / min, and the argon flow rate is 50L / min. After degassing is completed, let it stand for 10min to skim off the slag. After skimming off the slag, the temperature of the aluminum melt is adjusted to 730℃ and let it stand for 30min.

[0029] The second step is online processing. The online degassing gas is argon, the argon flow rate is 45L / min, and the rotor speed is 350r / min. Online grain refinement uses Al-5Ti-B for wire feeding, and the wire feeding ratio is 1.5kg / 1tAl. The filtration method uses plate filtration, 30PPi+50PPi.

[0030] The third step is to use oil-lubricated tooling for semi-continuous casting. The semi-continuous casting parameters are: casting end temperature 680-690℃, steady-state casting speed 52mm / min, water flow 18m 3 / h.

[0031] The fourth step is homogenization treatment, with a heating rate of 60℃ / h, a homogenization temperature of 495±5℃, a holding time of 16h after reaching the temperature, and a cooling method of air cooling + water mist cooling after reaching the temperature.

[0032] The fifth step is extrusion molding, the extrusion temperature is 385°C, and the extrusion speed is 0.15m / min.

[0033] The sixth step is solution aging treatment, solution temperature 510℃, holding time 30min, aging temperature 160℃, holding time 2.5h. Comparative Example 1

[0034] A method for preparing a high-silicon aluminum alloy material, comprising the following components by weight: Si: 13%, Cu: 1.2%, Mg: 1.5%, Ni: 0.9%, Ti: 0.03%, Sc: 0.16%, Sr: 0.055%, with the remainder being Al and unavoidable impurities, wherein the ratio of Cu to Sc is 7.5. The specific steps are as follows:

[0035] The first step is to calculate and prepare the ingredients according to the designed composition requirements, preheat the furnace to above 650℃ in advance, put 99.70% aluminum ingots, aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-nickel master alloy, and aluminum-scandium master alloy into the melting furnace, and set the melting furnace to 740℃ for heating and melting. After it is fully melted, introduce inert gas Ar above the melt in the furnace, and control the oxygen content at 200ppm. Add aluminum-titanium master alloy and aluminum-strontium master alloy, and then use the rotor in the furnace to degas and refine the aluminum melt. The refining time is 25min, the rotor speed is 450r / min, and the argon flow rate is 50L / min. After degassing is completed, let it stand for 10min to skim off the slag. After skimming off the slag, the temperature of the aluminum melt is adjusted to 730℃ and let it stand for 30min.

[0036] The second step is online processing. The online degassing gas is argon, the argon flow rate is 40L / min, and the rotor speed is 350r / min. Online grain refinement uses Al-5Ti-B for wire feeding, and the wire feeding ratio is 1.5kg / 1tAl. The filtration method uses plate filtration, 30PPi+50PPi.

[0037] The third step is to use oil-lubricated tooling for semi-continuous casting. The semi-continuous casting parameters are: casting end temperature 680-690℃, steady-state casting speed 52mm / min, water flow 18m 3 / h.

[0038] The fourth step is homogenization treatment, with a heating rate of 60℃ / h, a homogenization temperature of 495±5℃, a holding time of 16h after reaching the temperature, and a cooling method of air cooling + water mist cooling after reaching the temperature.

[0039] The fifth step is extrusion molding, the extrusion temperature is 385°C, and the extrusion speed is 0.15m / min.

[0040] The sixth step is solution aging treatment, solution temperature 510℃, holding time 30min, aging temperature 160℃, holding time 2.5h. Comparative Example 2

[0041] A method for preparing a high-silicon aluminum alloy material, comprising the following components by weight: Si: 13.0%, Cu: 1.7%, Mg: 1.6%, Ni: 0.10%, Ti: 0.03%, Sc: 0.05%, Sr: 0.06%, with the remainder being Al and unavoidable impurities, wherein the ratio of Cu to Sc is 34. The specific steps are:

[0042] The first step is to calculate and prepare the ingredients according to the designed composition requirements, preheat the furnace to above 650℃ in advance, put 99.70% aluminum ingots, aluminum-silicon master alloys, aluminum-copper master alloys, and aluminum-nickel master alloys into the melting furnace, and set the melting furnace to 740℃ for heating and melting. After fully melted, introduce inert gas Ar above the melt in the furnace, and control the oxygen content at 260ppm. Add aluminum-titanium master alloys and aluminum-strontium master alloys, and then use the rotor in the furnace to degas and refine the aluminum melt. The refining time is 20min, the rotor speed is 480r / min, and the argon flow rate is 50L / min. After degassing is completed, let it stand for 10min to skim off the slag. After skimming off the slag, the temperature of the aluminum melt is adjusted to 730℃ and let it stand for 30min.

[0043] The second step is online processing. The online degassing gas is argon, the argon flow rate is 45L / min, and the rotor speed is 350r / min. Online grain refinement uses Al-5Ti-B for wire feeding, and the wire feeding ratio is 1.5kg / 1tAl. The filtration method uses plate filtration, 30PPi+50PPi.

[0044] The third step is to use oil-lubricated tooling for semi-continuous casting. The semi-continuous casting parameters are: casting end temperature 680-690℃, steady-state casting speed 52mm / min, water flow 18m 3 / h.

[0045] The fourth step is homogenization treatment, with a heating rate of 60℃ / h, a homogenization temperature of 495±5℃, a holding time of 16h after reaching the temperature, and a cooling method of air cooling + water mist cooling after reaching the temperature.

[0046] The fifth step is extrusion molding, the extrusion temperature is 385°C, and the extrusion speed is 0.15m / min.

[0047] The sixth step is solution aging treatment, solution temperature 510℃, holding time 30min, aging temperature 160℃, holding time 2.5h. Comparative Example 3

[0048] A method for preparing a high-silicon aluminum alloy material comprises the following components by weight: Si: 13.0%, Cu: 1.6%, Mg: 1.6%, Ni: 0.10%, Ti: 0.03%, Sc: 0.4%, Sr: 0.055%, with the remainder being Al and unavoidable impurities, wherein Cu / Sc = 4. The specific steps are:

[0049] The first step is to calculate and prepare the ingredients according to the designed composition requirements, preheat the furnace to above 650℃ in advance, put 99.70% aluminum ingots, aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-nickel master alloy, and aluminum-scandium master alloy into the melting furnace, and set the melting furnace to 740℃ for heating and melting. After it is fully melted, introduce inert gas Ar above the melt in the furnace, and control the oxygen content at 260ppm. Aluminum-strontium master alloy and aluminum-titanium master alloy are added, and then the rotor in the furnace is used to degas and refine the aluminum melt. The refining time is 20min, the rotor speed is 480r / min, and the argon flow rate is 50L / min. After degassing is completed, let it stand for 10min to skim off the slag. After skimming off the slag, the temperature of the aluminum melt is adjusted to 730℃ and let it stand for 30min.

[0050] The second step is online processing. The online degassing gas is argon, the argon flow rate is 45L / min, and the rotor speed is 350r / min. Online grain refinement uses Al-5Ti-B for wire feeding, and the wire feeding ratio is 1.5kg / 1tAl. The filtration method uses plate filtration, 30PPi+50PPi.

[0051] The third step is to use oil-lubricated tooling for semi-continuous casting. The semi-continuous casting parameters are: casting end temperature 680-690℃, steady-state casting speed 52mm / min, water flow 18m 3 / h.

[0052] The fourth step is homogenization treatment, with a heating rate of 60℃ / h, a homogenization temperature of 495±5℃, a holding time of 16h after reaching the temperature, and a cooling method of air cooling + water mist cooling after reaching the temperature.

[0053] The fifth step is extrusion molding, the extrusion temperature is 385°C, and the extrusion speed is 0.15m / min.

[0054] The sixth step is solution aging treatment, solution temperature 510℃, holding time 30min, aging temperature 160℃, holding time 2.5h. Comparative Example 4

[0055] A method for preparing a high-silicon aluminum alloy material, comprising the following components by weight: Si: 11%, Cu: 1.7%, Mg: 1.5%, Ni: 0.9%, Ti: 0.03%, Sc: 0.14%, Sr: 0.055%, with the remainder being Al and unavoidable impurities, wherein the ratio of Cu to Sc is 12.1. The specific steps are as follows:

[0056] The first step is to calculate and prepare the ingredients according to the designed composition requirements, preheat the furnace to above 650℃ in advance, put 99.70% aluminum ingots, aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-nickel master alloy, and aluminum-scandium master alloy into the melting furnace, and set the melting furnace to 740℃ for heating and melting. After it is fully melted, introduce inert gas Ar above the melt in the furnace, and control the oxygen content at 200ppm. Add aluminum-titanium master alloy and aluminum-strontium master alloy, and then use the rotor in the furnace to degas and refine the aluminum melt. The refining time is 25min, the rotor speed is 450r / min, and the argon flow rate is 50L / min. After degassing is completed, let it stand for 10min to skim off the slag. After skimming off the slag, the temperature of the aluminum melt is adjusted to 730℃ and let it stand for 30min.

[0057] The second step is online processing. The online degassing gas is argon, the argon flow rate is 40L / min, and the rotor speed is 350r / min. Online grain refinement uses Al-5Ti-B for wire feeding, and the wire feeding ratio is 1.5kg / 1tAl. The filtration method uses plate filtration, 30PPi+50PPi.

[0058] The third step is to use oil-lubricated tooling for semi-continuous casting. The semi-continuous casting parameters are: casting end temperature 680-690℃, steady-state casting speed 52mm / min, water flow 18m 3 / h.

[0059] The fourth step is homogenization treatment, with a heating rate of 60℃ / h, a homogenization temperature of 495±5℃, a holding time of 16h after reaching the temperature, and a cooling method of air cooling + water mist cooling after reaching the temperature.

[0060] The fifth step is extrusion molding, the extrusion temperature is 385°C, and the extrusion speed is 0.15m / min.

[0061] The sixth step is solution aging treatment, solution temperature 510℃, holding time 30min, aging temperature 160℃, holding time 2.5h. Comparative Example 5

[0062] A method for preparing a high-silicon aluminum alloy material, comprising the following components by weight: Si: 12.8%, Cu: 1.7%, Mg: 1.5%, Ni: 0.9%, Ti: 0.03%, Sc: 0.15%, Sr: 0.055%, with the remainder being Al and unavoidable impurities, wherein the ratio of Cu to Sc is 11.3. The specific steps are:

[0063] The first step is to calculate and prepare the ingredients according to the designed composition requirements, preheat the furnace to above 650℃ in advance, put 99.70% aluminum ingots, aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-nickel master alloy, and aluminum-scandium master alloy into the melting furnace, and set the melting furnace to 740℃ for heating and melting. After fully melted, directly add aluminum-titanium master alloy and aluminum-strontium master alloy, and then use the rotor in the furnace to degas and refine the aluminum melt. The refining time is 25min, the rotor speed is 450r / min, and the argon flow rate is 50L / min. After degassing is completed, let it stand for 10min to skim off the slag. After skimming off the slag, the temperature of the aluminum melt is adjusted to 730℃ and let it stand for 30min.

[0064] The second step is online processing. The online degassing gas is argon, the argon flow rate is 40L / min, and the rotor speed is 350r / min. Online grain refinement uses Al-5Ti-B for wire feeding, and the wire feeding ratio is 1.5kg / 1tAl. The filtration method uses plate filtration, 30PPi+50PPi.

[0065] The third step is to use oil-lubricated tooling for semi-continuous casting. The semi-continuous casting parameters are: casting end temperature 680-690℃, steady-state casting speed 52mm / min, water flow 18m 3 / h.

[0066] The fourth step is homogenization treatment, with a heating rate of 60℃ / h, a homogenization temperature of 495±5℃, a holding time of 16h after reaching the temperature, and a cooling method of air cooling + water mist cooling after reaching the temperature.

[0067] The fifth step is extrusion molding, the extrusion temperature is 385°C, and the extrusion speed is 0.15m / min.

[0068] The sixth step is solution aging treatment, solution temperature 510℃, holding time 30min, aging temperature 160℃, holding time 2.5h.

[0069] The room temperature tensile properties of the high silicon aluminum alloy materials of Examples 1-2 and Comparative Examples 1-5 were tested to obtain the performance table shown in Table 1.

[0070] Table 1 Room temperature tensile properties of different high silicon aluminum alloys

[0071]

[0072] As can be seen from Table 1, controlling the content of each component of the high-silicon aluminum alloy material, especially controlling the content and ratio of Cu and Sc, can significantly and simultaneously improve the tensile strength, yield strength and elongation of the high-silicon aluminum alloy material.

[0073] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0074] The one or more embodiments of this application are intended to encompass all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this application should be included in the scope of protection of this application.

Claims

1. A high silicon aluminum alloy material, characterized in that: The raw material components include the following weight percentages: Si: 12-14%, Cu: 1.6-2.0%, Mg: 1.0-2.0%, Ni: 0.5-1.3%, Ti≤0.05%, Sc: 0.1-0.3%, Sr: 0.04-0.07%, and the balance is Al; the Cu / Sc ratio is 6-16:1; The method for preparing the high-silicon aluminum alloy material comprises the following steps: mixing the raw material components of the high-silicon aluminum alloy material, smelting, refining, online processing, semi-continuous casting, homogenization treatment, extrusion molding, solution treatment and aging treatment to obtain the high-silicon aluminum alloy material; During smelting, the temperature is 730-750°C, the oxygen content is controlled below 300 ppm, and inert gas is introduced above the melt.

2. The high silicon aluminum alloy material according to claim 1, wherein: The raw material components include the following weight percentages: Si: 12.5-13.5%, Cu: 1.6-2.0%, Mg: 1.3-1.7%, Ni: 0.7-1.2%, Ti: 0.02-0.04%, Sc: 0.13-0.25%, Sr: 0.05-0.065%, and the balance is Al; the Cu / Sc ratio is 8-13:

1.

3. The high silicon aluminum alloy material according to claim 2, wherein: The raw material components include the following weight percentages: Si: 12.8%, Cu: 1.7%, Mg: 1.5%, Ni: 0.9%, Ti: 0.03%, Sc: 0.14%, Sr: 0.055%, and the balance is Al.

4. A method for preparing a high-silicon aluminum alloy material according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: mixing raw material components of the high-silicon aluminum alloy material, smelting, refining, online processing, semi-continuous casting, homogenization treatment, extrusion molding, solution treatment and aging treatment to obtain the high-silicon aluminum alloy material; During smelting, the temperature is 730-750°C, the oxygen content is controlled below 300 ppm, and inert gas is introduced above the melt.

5. The preparation method according to claim 4, characterized in that: During online processing, the degassing gas is argon, the argon flow rate is 30-50L / min, the rotation speed is 300-450r / min, Al-5Ti-B is used for wire feeding, and the wire feeding ratio is 1.5kg / 1tAl; the filtration method is plate filtration.

6. The preparation method according to claim 4, wherein: During semi-continuous casting, the casting end temperature is controlled at 680-690℃, the steady-state casting speed is 50-55mm / min, and the water flow rate is 16-20m 3 / h.

7. The preparation method according to claim 4, characterized in that: During homogenization treatment, the heating rate is controlled at 50-60°C / h, the homogenization temperature is 490-500°C, and the holding time is 14-18h.

8. The preparation method according to claim 4, wherein: During extrusion molding, the extrusion temperature is controlled at 370-410°C and the extrusion speed is controlled at 0.1-0.3m / min.

9. The preparation method according to claim 4, wherein: The temperature of solid solution is 505-515℃, and the holding time is 20-40min; the temperature of aging treatment is 155-165℃, and the holding time is 2-4h.

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