High-modulus heat-resistant low-cost aluminum alloy material and preparation method thereof

Abstract

The invention discloses a high-modulus heat-resistant low-cost aluminum alloy material and a preparation method thereof, and the high-modulus heat-resistant low-cost aluminum alloy material is prepared from the following components in percentage by weight: 3.0 to 5.5 weight percent of Cu, 2.0 to 3.0 weight percent of Mg, 0.3 to 0.8 weight percent of Mn, 0.02 to 0.2 weight percent of Zn, 0.05 to 0.15 weight percent of Ti, 0.02 to 0.1 weight percent of Ni, 1 to 3.5 weight percent of nano TiB2 particles with the particle size of 10 to 100nm, and the balance of Al and inevitable impurity elements. The preparation method comprises the following steps: standing and cooling an intermediate melt to 580-620 DEG C to enable the intermediate melt to be in a semi-solid state, then carrying out slagging-off treatment, then mechanically stirring the melt through a stirring device, quickly adding nano TiB2 particles packaged by pure aluminum tubes after the melt forms stable vortexes, continuously mechanically stirring in one direction for 10-15 minutes after the addition is completed, and carrying out cooling to obtain the nano TiB2 particles. And then carrying out reverse stirring for 10-15 min. According to the method, the low cost of the material end is achieved, efficient adding and uniform dispersing of the nano TiB2 particles are achieved, and the obdurability and elasticity modulus of the aluminum alloy under the high-temperature condition are further efficiently improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloy preparation, and particularly relates to a high-modulus heat-resistant low-cost aluminum alloy material and a preparation method thereof. Background Art

[0002] Aluminum alloy materials have the advantages of light weight, high specific strength and good processing performance, and are widely used in the fields of aerospace, weapons and equipment, etc. In particular, they play an irreplaceable role in equipment lightweighting and improving combat performance such as mobility and reliability. However, after the use temperature of aluminum alloy exceeds 150 °C, its performance begins to decline sharply, making it difficult to meet the high-temperature service conditions of equipment. Therefore, developing high-strength heat-resistant aluminum alloys is the key research direction in the field of aluminum alloy materials at present.

[0003] The existing literature CN103484739B discloses an Al-Cu-Mg-Mn series high-strength heat-resistant aluminum alloy profile and a manufacturing method thereof. The alloy components are Cu: 3.5-4.2 wt%, Mg: 0.3-0.4 wt%, Zr: 0.3-0.4 wt%, Mn: 0.2-0.3 wt%, Mo: 0.08-0.12 wt%, Ni: 0.03-0.05 wt%, Ti: 0.04-0.08 wt%, V: 0.02-0.03 wt%, B: 0.03-0.04 wt%, Fe: 0.02-0.03 wt%, Ce: 0.04-0.07 wt%, Er: 0.03-0.05 wt%, Nd: 0.05-0.08 wt%, and the balance is Al. Although the room-temperature tensile strength of this aluminum alloy profile reaches 589 MPa, the yield strength is 465 MPa, and the elongation rate is 13.2%, its high-temperature strength and elastic modulus are not described in detail, and due to the addition of expensive rare earth elements such as Mo, Ce, Er, and Nd, the cost is relatively high. In addition, the literature CN112620387B discloses a method for preparing a high-modulus aluminum alloy conductive tube with nano-reinforced phases. SiC nano-particles or carbon nanotubes CNTs are used to reinforce 6005 aluminum alloy, and the prepared aluminum matrix composite material has relatively excellent room-temperature properties. Its room-temperature elastic modulus reaches 99 GPa, and the tensile strength reaches 326 MPa, but its high-temperature elastic modulus and strength are still unknown.

[0004] Research shows that introducing nano-reinforced phases into aluminum alloy materials can effectively improve their mechanical properties, but how to uniformly and effectively introduce nano-reinforced phases (especially high-temperature stable nano-particles) has always been a technical difficulty faced by this field. In the existing operation methods, usually, the lump of nano-reinforced phases wrapped with aluminum foil is directly added to the melt. The main drawback of this method is that the nano-reinforced phases cannot be uniformly introduced, resulting in a large part (especially the end part) of the prepared material being waste that needs to be cut off. Summary of the Invention

[0005] At least to solve the technical problems mentioned in the background art, the purpose of the present invention is to provide a high-modulus heat-resistant low-cost aluminum alloy material and a preparation method thereof.

[0006] The present invention adopts the following technical solutions.

[0007] A high-modulus heat-resistant low-cost aluminum alloy material, the raw materials of which are composed of the following components by weight percentage: Cu: 3.0 - 5.5 wt%, Mg: 2.0 - 3.0 wt%, Mn: 0.3 - 0.8 wt%, Zn: 0.02 - 0.2 wt%, Ti: 0.05 - 0.15 wt%, Ni: 0.02 - 0.1 wt%, nano-TiB particles with a particle size of 10 - 100 nm: 1 - 3.5 wt%, and the balance is Al and inevitable impurity elements. 2 The balance is Al and inevitable impurity elements.

[0008] As one of the preferred solutions of the present invention, in its raw materials, Cu: 5.2 wt%, Mg: 2.4 wt%, Mn: 0.4 wt%, Zn: 0.1 wt%, Ti: 0.08 wt%, Ni: 0.05 wt%, and the average particle size of nano-TiB particles: 80 nm: 2 wt%. 2 The balance is Al and inevitable impurity elements.

[0009] As the second preferred solution of the present invention, in its raw materials, Cu: 3.5 wt%, Mg: 2 wt%, Mn: 0.5 wt%, Zn: 0.15 wt%, Ti: 0.09 wt%, Ni: 0.06 wt%, and the average particle size of nano-TiB particles: 80 nm: 3 wt%. 2 The balance is Al and inevitable impurity elements.

[0010] A preparation method of the aforementioned aluminum alloy material, the steps include: Step 1, using pure aluminum, pure magnesium, pure zinc, aluminum-copper alloy, aluminum-manganese alloy, aluminum-titanium alloy, aluminum-nickel alloy, and nano-TiB particles as raw materials, and proportioning according to the aforementioned weight percentages; wherein, the nano-TiB particles are encapsulated with pure aluminum tubes; 2 The nano-TiB particles are encapsulated with pure aluminum tubes; 2 The nano-TiB particles are encapsulated with pure aluminum tubes; Step 2, after all the pure aluminum ingots in the container are melted, successively add pure magnesium, pure zinc, aluminum-copper alloy, aluminum-manganese alloy, aluminum-titanium alloy, aluminum-nickel alloy. After all the added raw materials are melted, stir the interior of the melt to make the melt composition uniform to obtain an intermediate melt; Step 3, let the obtained intermediate melt stand and cool down to 580 - 620 °C to make it in a semi-solid state, then carry out slag skimming treatment, and then mechanically stir the melt through a stirring device. After the melt forms a stable vortex, quickly add the nano-TiB particles encapsulated with pure aluminum tubes 2Particles are added. After the addition is completed, mechanical stirring is continued in one direction for 10 - 15 minutes, and then in the reverse direction for 10 - 15 minutes to obtain a mixed melt. Step 4: The obtained mixed melt is allowed to stand and rapidly heated to 700 - 720 °C. Meanwhile, an ultrasonic device and an electromagnetic stirring device are turned on to perform an external field intervention treatment on the melt. Among them, the direction of the sound wave generated by the ultrasonic device is the axial direction of the melt, and the direction of the magnetic field generated by the electromagnetic stirring device is the transverse direction of the melt. Step 5: After step 4 is completed, the melt is allowed to stand and then cast into an ingot mold preheated to 250 - 300 °C to obtain an ingot after completion. Step 6: The obtained ingot is subjected to homogenization treatment to obtain a blank. The homogenization treatment time is calculated according to the diameter or thickness of the ingot: t = A / 1.5 (mm / min) + 60 min. Step 7: The obtained blank is directly subjected to extrusion deformation. The extrusion ratio is not less than 10:1. The extrusion temperature of the blank is 440 - 480 °C, and the extrusion rate is 3 - 6 mm / s. The extruded bar is subjected to water cooling treatment. Step 7: After step 7 is completed, the bar is subjected to secondary strengthening and toughening treatment. The solution temperature is 500 - 505 °C, and the holding time is 5 - 7 h. It is quenched in water within 20 s after the holding is completed. The aging temperature is 185 - 190 °C, and the holding time is 18 - 24 h.

[0011] In order to uniformly and effectively introduce nano - TiB 2 particle reinforced phase, the pure aluminum tube encapsulating nano - TiB 2 particles uses a jacketed tube. The nano - TiB 2 particles are located in the inner cavity of the jacketed tube. The inner wall of the jacketed tube is 100 - 200 mm larger than the axis of the container and is located outside the stirring shaft. The thickness of the inner cavity of the jacketed tube is 3 - 8 mm.

[0012] In order to more uniformly and effectively introduce nano - TiB 2 particle reinforced phase, the inner cavity of the jacketed tube has several mutually independent and uniformly arranged small chambers, and the nano - TiB 2 particles are filled in the small chambers.

[0013] In another solution, the pure aluminum tube encapsulating nano - TiB 2 particles uses multiple straight tubes with an outer diameter of 20 mm and a wall thickness of 1 - 2.5 mm. All the straight tubes are arranged in a multi - point uniform manner around the axis of the container.

[0014] Preferably, the step of adding nano - TiB 2 particles encapsulated in a pure aluminum tube is as follows: The nano - TiB 2The pure aluminum tube of the particles is installed at the lower end of the telescopic rod of the lifting mechanism. The lifting mechanism is located above the container. Control the telescopic rod of the lifting mechanism to move downward at a constant speed according to the set speed until the pure aluminum tube containing nano-TiB 2 particles extends into the melt and completely melts.

[0015] Preferably, during the external field intervention treatment, the ultrasonic frequency is 20 kHz, the power is 25 - 30 KW, the magnetic field intensity is 800 - 1000 Gs, and the external field intervention treatment time is 20 - 30 min.

[0016] Beneficial effects: The present invention adopts a specific alloy composition ratio, and at the same time introduces high-modulus high-temperature stable phase nano-TiB 2 particles, and then cooperates with a specific introduction method of nano-TiB 2 particles and the combined external field of "ultrasonic + magnetic force" to jointly act, not only realizing the low-cost of the material end, but also realizing the efficient addition and uniform dispersion of nano-TiB 2 particles, and also efficiently improving the strength, toughness and elastic modulus of the aluminum alloy under high-temperature conditions. The key is to reduce the proportion of surface waste of the obtained material; the aluminum alloy material prepared by the present invention has good alloy tissue uniformity, uniform morphology and spatial distribution of strengthening phases, good stability and consistency of alloy properties, and excellent mechanical properties. Description of the Drawings

[0017] Figure 1 Partial schematic diagram of the external structure of the pure aluminum tube encapsulating nano-TiB 2 particles in Example 1; Figure 2 Partial schematic diagram of the internal structure of the pure aluminum tube encapsulating nano-TiB 2 particles in Example 1; Figure 3 Schematic diagram of adding nano-TiB 2 particles encapsulated by a pure aluminum tube in Example 1, and the arrow indicates the moving direction of the pure aluminum tube; Figure 4 Schematic diagram of adding nano-TiB 2 particles encapsulated by a pure aluminum tube in Example 3. Detailed Embodiments

[0018] Combined with the drawings below, the technical solutions in the present invention are described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Example 1

[0019] A high-modulus, heat-resistant and low-cost aluminum alloy material, the raw materials of which are composed of the following components by weight percentage: Cu: 5.2wt%, Mg: 2.4wt%, Mn: 0.4wt%, Zn: 0.1wt%, Ti: 0.08wt%, Ni: 0.05wt%, and nano-TiB with an average particle size of 80nm 2 particles: 2wt%, and the balance is Al and inevitable impurity elements.

[0020] The preparation method of the high-modulus, heat-resistant and low-cost aluminum alloy material in this embodiment is as follows: Step 1, using pure aluminum, pure magnesium, pure zinc, aluminum-copper alloy, aluminum-manganese alloy, aluminum-titanium alloy, aluminum-nickel alloy, and nano-TiB 2 particles as raw materials, proportioning according to the aforementioned weight percentages, and considering the burning loss of each alloy element; Step 2, after all the pure aluminum ingots in the container are melted, add pure magnesium, pure zinc, aluminum-copper alloy, aluminum-manganese alloy, aluminum-titanium alloy, and aluminum-nickel alloy in sequence. After all the added raw materials are melted, stir the inside of the melt to make the melt composition uniform to obtain an intermediate melt; Step 3, let the obtained intermediate melt stand and cool down to 615°C to make it in a semi-solid state, then skim the slag from the melt, and then mechanically stir the melt through a stirring device. After the melt forms a stable vortex, quickly add nano-TiB 2 particles encapsulated in a pure aluminum tube. After the addition is completed, continue to mechanically stir in one direction for 10 minutes, and then stir in the reverse direction for 15 minutes to obtain a mixed melt; In this step, as shown in Figures 1 to 3 The pure aluminum tube 3 encapsulating the nano-TiB 2 particles 5 adopts a jacketed tube. The nano-TiB 2 particles 5 are located in the inner cavity of the jacketed tube. The inner wall of the jacketed tube is 150 mm larger than the axis of the container and is located outside the stirring shaft (the inner diameter of the container is 780 mm, the stirring shaft coincides with the axis of the container and has a diameter of 30 mm), and the inner cavity thickness of the jacketed tube is 5 mm; the inner cavity of the jacketed tube has several mutually independent and uniformly arranged small chambers 6 separated by a partition plate 4. The wall thickness of the partition plate 4 is 12 mm, and the side length of each small chamber 6 is 8*8 mm. The nano-TiB 2 particles 5 are filled in the small chambers 6; the step of adding nano-TiB 2 particles 5 encapsulated in a pure aluminum tube 3 is as follows: Install the pure aluminum tube 3 containing nano-TiB 2 particles 5 at the lower end of the telescopic rod of the lifting mechanism. The lifting mechanism is located above the container 1. Control the telescopic rod of the lifting mechanism to move downwards at a set speed uniformly until the pure aluminum tube 3 containing nano-TiB 2 particles 5 extends into the melt 2 and is completely melted; In this solution, the phenomenon that the flow velocity at the edge of the melt 2 vortex is relatively slow and the flow velocity in the middle of the vortex is relatively fast is cleverly utilized. A pure aluminum tube 3 with the above-mentioned specific annular structure encapsulating nano-TiB 2 particles 5 is introduced near the melt 2 vortex in the container 1, ensuring the uniformity of material dispersion at the source of adding the particulate material, and realizing the efficient and uniform introduction of nano-TiB 2 particles 5 into the melt. It can also reduce the proportion of waste at the ends of the prepared materials. In particular, several independent and uniformly arranged small chambers 6 separated by a partition 4 cooperate with other features to jointly prevent the agglomeration of TiB 2 particles 5; Step 4: Keep the obtained mixed melt still and rapidly heat it to 720 °C. At the same time, turn on the ultrasonic device and the electromagnetic stirring device to perform external field intervention treatment on the melt. The ultrasonic frequency is 20 kHz, and the power is 30 kW; the electromagnetic stirring frequency is 15 Hz, the magnetic field strength is 900 Gs, and the external field intervention treatment time is 25 min; Step 5: After step 4 is completed, keep the mixed melt still for 10 min, and then pour it into an ingot mold preheated to 280 °C. After that, an ingot with a specification of Φ650 mm × 700 mm is obtained; Step 6: Heat the obtained ingot to 500 °C for homogenization treatment to obtain a blank, and the holding time is 493 min; Step 7: Directly perform extrusion deformation on the obtained blank. The extrusion ratio is 10:1, the extrusion temperature of the blank is 460 °C, the extrusion rate is 4 mm / s, and the extruded bar is subjected to water cooling treatment; Step 8: After step 7 is completed, perform secondary strengthening and toughening treatment on the bar. The solution temperature is 503 °C, hold for 6 h, and quench in water within 20 s after the holding is completed. The aging temperature is 190 °C, hold for 18 h, and a high-modulus heat-resistant low-cost aluminum alloy material (bar) is obtained.

[0021] The mechanical properties of the high-modulus heat-resistant low-cost aluminum alloy material prepared in this example are shown in Table 1, Table 1 Mechanical properties of high-modulus heat-resistant low-cost aluminum alloy material (bar) Example 2

[0022] A high-modulus heat-resistant low-cost aluminum alloy material, the raw materials of which are composed of the following components by weight percentage: Cu: 3.5 wt%, Mg: 2 wt%, Mn: 0.5 wt%, Zn: 0.15 wt%, Ti: 0.09 wt%, Ni: 0.06 wt%, nano-TiB 2 particles with an average particle diameter of 80 nm: 3 wt%, and the balance is Al and inevitable impurity elements.

[0023] In this embodiment, the preparation method of the high-modulus heat-resistant low-cost aluminum alloy material is as follows: Step 1: Using pure aluminum, pure magnesium, pure zinc, aluminum-copper alloy, aluminum-manganese alloy, aluminum-titanium alloy, aluminum-nickel alloy, and nano-TiB 2 particles as raw materials, proportion the ingredients according to the aforementioned weight percentages, and consider the burning loss of each alloy element; Step 2: After all the pure aluminum ingots in the container are melted, add pure magnesium, pure zinc, aluminum-copper alloy, aluminum-manganese alloy, aluminum-titanium alloy, and aluminum-nickel alloy in sequence. After all the added raw materials are melted, stir the inside of the melt to make the melt composition uniform to obtain an intermediate melt; Step 3: Let the obtained intermediate melt stand and cool down to 620 °C to make it in a semi-solid state. Then, skim the slag from the melt, and then mechanically stir the melt through a stirring device. After the melt forms a stable vortex, quickly add nano-TiB 2 particles encapsulated in a pure aluminum tube. After the addition is completed, continue to mechanically stir in one direction for 15 min, and then stir in the reverse direction for 18 min to obtain a mixed melt; In this step, the pure aluminum tube encapsulating the nano-TiB 2 particles uses a jacketed tube. The nano-TiB 2 particles are located in the inner cavity of the jacketed tube. The inner wall of the jacketed tube is 180 mm larger than the axis of the container and is located outside the stirring shaft (the inner diameter of the container is 780 mm, the stirring shaft coincides with the axis of the container and has a diameter of 40 mm), and the inner cavity thickness of the jacketed tube is 4 mm; the inner cavity of the jacketed tube has several mutually independent and uniformly arranged small chambers separated by partition plates. The wall thickness of the partition plate is 10 mm, and the side length of each small chamber is 10 * 10 mm. The nano-TiB 2 particles are filled in the small chambers; the step of adding nano-TiB 2 particles encapsulated in a pure aluminum tube is as follows: Install the pure aluminum tube containing nano-TiB 2 particles at the lower end of the telescopic rod of the lifting mechanism. The lifting mechanism is located above the container. Control the telescopic rod of the lifting mechanism to move down uniformly at a set speed until the pure aluminum tube containing nano-TiB 2 particles extends into the melt and is completely melted; Step 4: Let the obtained mixed melt stand and quickly heat it up to 715 °C. At the same time, turn on the ultrasonic device and the electromagnetic stirring device to perform external field intervention treatment on the melt. The ultrasonic frequency is 20 kHz, and the power is 28 kW; the electromagnetic stirring frequency is 15 Hz, and the magnetic field strength is 1000 Gs. The external field intervention treatment time is 20 min; Step 5: After Step 4 is completed, let the mixed melt stand for 10 min, and then pour it into a ingot mold preheated to 300 °C. After completion, an ingot with a specification of Φ720 mm × 600 mm is obtained; Step 6: Heat the obtained ingot to 500 °C for homogenization treatment to obtain a blank, with a holding time of 460 min; Step 7: Directly subject the obtained blank to extrusion deformation, with an extrusion ratio of 16:1, an extrusion temperature of the blank of 460 °C, and an extrusion rate of 3 mm / s. Water-cool the extruded bar; Step 8: After Step 7, perform secondary strengthening and toughening treatment on the bar. The solution temperature is 503 °C, hold for 6 h, quench in water within 20 s after the holding is completed, and the aging temperature is 190 °C, hold for 20 h to obtain a high-modulus heat-resistant low-cost aluminum alloy material (bar).

[0024] In this embodiment, the mechanical properties of the obtained high-modulus heat-resistant low-cost aluminum alloy material are shown in Table 2. Table 2 Mechanical properties of high-modulus heat-resistant low-cost aluminum alloy material (bar)

[0025] Comparative Example 1: Refer to Example 1. The difference from Example 1 is that the method of adding nano-TiB 2 particles in Step 3 is different: Let the obtained intermediate melt stand and cool to 615 °C to make it in a semi-solid state, then skim the slag from the melt, and then mechanically stir the melt through a stirring device. During the mechanical stirring process, add nano-TiB 2 particles wrapped in pure aluminum foil. After the addition is completed, continue to mechanically stir in one direction for 10 min, and then stir in the reverse direction for 15 min to obtain a mixed melt.

[0026] Detect the aluminum alloy material prepared in Comparative Example 1, and the results are shown in Table 3. Mechanical properties of aluminum alloy material (bar)

[0025] In addition, there is no waste at the top of the high-modulus heat-resistant low-cost aluminum alloy material (bar) prepared in Example 1 and Example 2, while the length / thickness of the waste at the top of the aluminum alloy material (bar) prepared in Comparative Example 1 is 50 - 100 mm, and the length / thickness of the waste at the bottom is 40 - 80 mm; the top tissue of the high-modulus heat-resistant low-cost aluminum alloy material prepared in Example 1 and Example 2 is uniformly good, without particle agglomeration, while the aluminum alloy material (bar) prepared in Comparative Example 1 has a large number of agglomerates at the top (i.e., nano-TiB 2 particle agglomerates).

[0027] Example 3: Refer to Example 1. The difference from Example 1 is that as Figure 4 shown, the pure aluminum tubes 3 encapsulating nano-TiB2 particles are multiple straight tubes with an outer diameter of 20 mm and a wall thickness of 2 mm. All the straight tubes are arranged evenly at multiple points around the axis of the container 1.

Claims

1. A high modulus, heat-resistant and low-cost aluminum alloy material, characterized in that: Its raw materials are composed of the following components in weight percentage: Cu: 3.0-5.5wt%, Mg: 2.0-3.0wt%, Mn: 0.3-0.8wt%, Zn: 0.02-0.2wt%, Ti: 0.05-0.15wt%, Ni: 0.02-0.1wt%, nano-TiB2 particles with a particle size of 10-100nm: 1-3.5wt%, and the remainder is Al and inevitable impurity elements.

2. The aluminum alloy material according to claim 1, characterized in that: Its raw materials include Cu: 5.2wt%, Mg: 2.4wt%, Mn: 0.4wt%, Zn: 0.1wt%, Ti: 0.08wt%, Ni: 0.05wt%, and nano-TiB2 particles with an average particle size of 80nm: 2wt%.

3. The aluminum alloy material according to claim 1, characterized in that: Its raw materials include Cu: 3.5wt%, Mg: 2wt%, Mn: 0.5wt%, Zn: 0.15wt%, Ti: 0.09wt%, Ni: 0.06wt%, and nano-TiB2 particles with an average particle size of 80nm: 3wt%.

4. A method for preparing the aluminum alloy material according to any one of claims 1 to 3, characterized in that the steps include: Step 1, using pure aluminum, pure magnesium, pure zinc, aluminum-copper alloy, aluminum-manganese alloy, aluminum-titanium alloy, aluminum-nickel alloy, and nano-TiB2 particles as raw materials, and preparing ingredients according to weight percentage; wherein the nano-TiB2 particles are packaged in pure aluminum tubes; Step 2, after all the pure aluminum ingots in the container are melted, pure magnesium, pure zinc, aluminum-copper alloy, aluminum-manganese alloy, aluminum-titanium alloy, and aluminum-nickel alloy are added in sequence, and after all the added raw materials are melted, the melt is stirred to make the melt composition uniform to obtain an intermediate melt; Step 3, the obtained intermediate melt is cooled to 580-620°C to make it in a semi-solid state, followed by slagging treatment, and then the melt is mechanically stirred by a stirring device, and after the melt forms a stable vortex, the nano-TiB2 particles encapsulated in a pure aluminum tube are quickly added, and after the addition is completed, mechanical stirring is continued in one direction for 10-15 minutes, and then reverse stirring is continued for 10-15 minutes to obtain a mixed melt; Step 4, allowing the obtained mixed melt to stand and rapidly heating it to 700-720° C., while turning on an ultrasonic device and an electromagnetic stirring device to perform external field intervention treatment on the melt; wherein the direction of the sound wave generated by the ultrasonic device is the axial direction of the melt, and the direction of the magnetic field generated by the electromagnetic stirring device is the transverse direction of the melt; Step 5, after step 4 is completed, the melt is allowed to stand and then cast into an ingot mold preheated to 250-300° C., and an ingot is obtained after completion; Step 6, homogenizing the obtained ingot to obtain a billet; Step 7, directly extruding the obtained billet, with an extrusion ratio of not less than 10:1, a billet extrusion temperature of 440-480° C., an extrusion rate of 3-6 mm / s, and water cooling the extruded rod; Step 7. After step 7, the rod is subjected to secondary toughening treatment, the solution temperature is 500-505°C, and the insulation is 5-7h. After the insulation is completed, it is quenched in water within 20s, and the aging temperature is 185-190)°C, and the insulation is 18-24h.

5. The method for preparing the aluminum alloy material according to claim 4, characterized in that: The pure aluminum tube encapsulating the nano-TiB2 particles adopts a jacket tube, the nano-TiB2 particles are located in the inner cavity of the jacket tube, the inner wall of the jacket tube is 100-200 mm larger than the axis of the container and is located outside the stirring shaft (the inner diameter of the container is not less than 600 mm), and the inner cavity thickness of the jacket tube is 3-8 mm.

6. The method for preparing the aluminum alloy material according to claim 5, characterized in that: The inner cavity of the jacket tube has a plurality of small chambers which are independent of each other and evenly arranged, and the nano-TiB2 particles are filled in the small chambers.

7. The method for preparing the aluminum alloy material according to claim 4, characterized in that: The pure aluminum tubes for encapsulating nano-TiB2 particles are multiple straight tubes with an outer diameter of 20 mm and a wall thickness of 1 to 2.5 mm, and all the straight tubes are evenly arranged around the axis of the container.

8. The method for preparing the aluminum alloy material according to claim 7, characterized in that: The steps of adding nano-TiB2 particles encapsulated in a pure aluminum tube are as follows: the pure aluminum tube containing nano-TiB2 particles is installed at the lower end of the telescopic rod of the lifting mechanism, the lifting mechanism is located above the container, and the telescopic rod of the lifting mechanism is controlled to move downward at a uniform speed at a set speed until the pure aluminum tube containing nano-TiB2 particles is extended into the melt and completely melted.

9. The method for preparing the aluminum alloy material according to any one of claims 5 to 8, characterized in that: During the external field intervention treatment, the ultrasonic frequency is 20kHz, the power is 25-30KW, the magnetic field strength is 800-1000Gs, and the external field intervention treatment time is 20-30min.

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