7-series aluminum alloy profile as well as processing method and application thereof

Abstract

The invention discloses a 7-series aluminum alloy profile as well as a processing method and application thereof. The 7-series aluminum alloy profile is prepared from the following components in percentage by weight: 1.15 to 1.26 percent of Mg, 0.05 to 0.12 percent of Si, 0.2 to 0.28 percent of Cu, less than or equal to 0.05 percent of Mn, less than or equal to 0.05 percent of Cr, 0.01 to 0.04 percent of Ti, 0.1 to 0.28 percent of Fe, 6.55 to 6.75 percent of Zn, 0.1 to 0.2 percent of Zr, 0.05 to 0.12 percent of Mg (Zn, Cu and Al) 2 particles, 0.1 to 0.15 percent of rare earth high-entropy alloy particles and the balance of Al. Wherein the components of the rare earth high-entropy alloy particles are La (15-25) Pr (15-25) Gd (15-25) Dy (15-25) Y (15-25). The processing method of the 7-series aluminum alloy comprises the following steps: S1, melting and casting; s2, homogenizing the stress; s3, extruding; s4, carrying out online quenching; s5, stretching and straightening; and S6, artificial aging treatment. The aluminum alloy profile obtained through the machining method has the good mechanical property, the production cost is increased by 40% or above compared with a conventional 7-series aluminum alloy, the service life of a mold is prolonged by 40% or above, and the aluminum alloy profile is applied to automobile lightweight aluminum alloy.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material processing, and particularly relates to a 7-series aluminum alloy profile and its processing method and application. Background Art

[0002] Automobile lightweighting is the technical development direction of the world's automobile innovation project today and the forefront and hot spot of the world's automobile technology innovation in the 21st century. Compared with steel, aluminum alloy has the characteristics of light weight, good corrosion resistance, easy processing, etc., and the content of aluminum in the earth's crust is abundant. Therefore, it has become the preferred lightweight material for automobiles in the past 20 years. With the development of automobile lightweighting, the use of aluminum alloy profiles in automobile parts is increasing. In order to give full play to the weight reduction advantage as much as possible, it is required that the structure of aluminum alloy profiles is more and more complex, and there are more and more weight reduction cavities. At the same time, it is required to take into account excellent mechanical properties and good extrusion efficiency. Conventional 7-series aluminum alloys are difficult to balance mechanical properties and extrusion efficiency when producing multi-cavity aluminum alloy profiles. The service life of a set of dies is usually 4T. The service life of dies is an important part of production costs. The improvement of the die service life can effectively reduce production costs. With the development of the industry and the competitive demand of the market, there is an urgent need to develop a 7-series aluminum alloy that not only has excellent mechanical properties but also has high efficiency and low cost. Summary of the Invention

[0003] Technical problems to be solved: The technical problem to be solved by the present invention is to provide a 7-series aluminum alloy profile and its processing method and application, which solves the problem of difficulty in balancing mechanical properties and production costs in the prior art, and particularly solves the problem of low extrusion efficiency of multi-cavity aluminum alloy profiles.

[0004] Technical solution: A 7-series aluminum alloy profile, the 7-series aluminum alloy is composed of the following weight percentages: Mg: 1.15 - 1.26 wt.%, Si: 0.05 - 0.12 wt.%, Cu: 0.2 - 0.28 wt.%, Mn: ≤0.05 wt.%, Cr: ≤0.05 wt.%, Ti: 0.01 - 0.04 wt.%, Fe: 0.1 - 0.28 wt.%, Zn: 6.55 - 6.75 wt.%, Zr: 0.1 - 0.2 wt.%, Mg(Zn,Cu,Al) 2 particles: 0.05 - 0.12 wt.%, rare earth high-entropy alloy particles: 0.1 - 0.15 wt.%, and the balance is Al. Preferably, the rare earth high-entropy alloy particles are composed of La 15-25 Pr 15-25 Gd 15-25 Dy 15-25 Y 15-25 . Preferably, the processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials according to a ratio, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them warm and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Perform homogenization treatment on the aluminum alloy ingot and keep it warm, and then cool it at a cooling rate of ≥200 °C / h; S3. Preheat the mold, and put the aluminum alloy bar into an extruder for extrusion to obtain an aluminum alloy bar; S4. Perform online quenching treatment on the extruded bar at a cooling rate of ≥200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S6. Perform aging treatment on the aluminum alloy profile to obtain a 7-series aluminum alloy profile. Preferably, the holding temperature of the alloy melt in step S1 is 620-660 °C, and the holding time is 15-25 min. Preferably, the treatment temperature in step S2 is 450-480 °C, the heating rate is 80-230 °C / h, and the holding time is 5-20 h. Preferably, the preheating temperature of the mold in step S3 is 485-505 °C, the temperature of the head of the bar during extrusion is 500-515 °C, the temperature of the tail is 460-480 °C, the speed of the extrusion rod is 1.5-3.0 m / s, and the outlet temperature is 500-520 °C. Preferably, the online quenching treatment method in step S4 includes any one of forced air cooling, water mist cooling, spray cooling and water through cooling treatment. Preferably, the aging treatment temperature in step S6 is 170-190 °C, and the holding time is 6-12 h. Preferably, the 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Beneficial effects: Compared with the prior art, the present invention has the following characteristics: The present invention controls the content of the main alloying elements, and slightly adds second-phase strengthening particles and rare-earth high-entropy alloys. While ensuring the mechanical properties of the alloy, it effectively increases the extrusion speed, improves the dimensional stability of the profiles, and greatly extends the service life of the die. Mg, Si, and Cu are common strengthening elements in aluminum alloys. Appropriate addition can effectively improve the mechanical properties and corrosion resistance of the alloy. However, the addition of excessive Mg and Si will produce embrittlement phases, reducing the plasticity of the alloy. An excessively high Cu content will also exacerbate intergranular corrosion. Therefore, strictly regulating the content and ratio of these elements is the first step in optimizing the mechanical properties, corrosion resistance, and workability of aluminum alloys. For aluminum alloys, rare earth is a good modifier and refiner, which can refine grains, modify eutectic silicon, and degas and refine. After high-entropy treatment of rare earth, the obtained rare-earth high-entropy alloy has high strength, high hardness, good oxidation resistance and thermal stability, and can also be used as a reinforcement for aluminum alloys to further improve the comprehensive mechanical properties of the alloy. In addition to rare-earth elements that can improve the mechanical properties of aluminum alloys, second-phase particles can also increase the strength of aluminum alloys through dispersion strengthening and precipitation strengthening: fine and uniformly distributed hard second-phase particles can hinder the movement of dislocations, thereby increasing the dislocation density and further enhancing the strength of the material; second-phase particles can also pin the grain boundaries, slow down the recrystallization process, make the grain size smaller, and further enhance the strength of the material; in addition, second-phase particles also affect the recrystallization behavior of aluminum alloys. Therefore, by controlling the content and distribution of second-phase particles, the recrystallization behavior of aluminum alloys can be optimized, thereby improving the microstructure and mechanical properties of the material. During the solidification process of aluminum alloys, dendritic segregation is likely to occur, causing uneven distribution of elements within grains and grain boundaries, resulting in deterioration of the strength, plasticity, and workability of the alloy. Therefore, homogenization treatment must be carried out on the alloy to eliminate or reduce the inhomogeneity of composition and structure, gradually dissolve the non-equilibrium phases in the alloy, and thus improve the alloy properties. In addition to homogenization treatment, as a kind of aluminum alloy strengthened by precipitated phases, 7000 series aluminum alloys also require aging treatment. After appropriate aging treatment, solute atoms can precipitate from the solid solution to form fine precipitate phases, thereby generating pinning sites to hinder dislocation movement and improving the strength and hardness of the alloy. Compared with the prior art, the present invention has the following advantages and positive effects: The present invention controls the content of the main alloying elements Mg, Si, and Cu, and adds rare-earth high-entropy alloys and second-phase particles to improve the alloy structure and enhance the mechanical properties of the alloy. The aluminum alloy profiles prepared by the present invention have good comprehensive properties. The extrusion speed is increased by more than 30% compared with conventional 6061 aluminum alloy, and the service life of the die is increased by 50%. The processing method provided by the present invention enables the effective period of the T4 state to reach more than 40 days, and the T5 aging treatment time is shortened by 25-50% compared with the original. Detailed implementation manners To further understand the present invention, the preferred embodiments of the present invention will be described below in conjunction with examples. Specific preferred examples are as follows: Example 1: A 7-series aluminum alloy profile, the 7-series aluminum alloy consists of the following weight percentages: Mg: 1.15 wt.%, Si: 0.05 wt.%, Cu: 0.20 wt.%, Ti: 0.01 wt.%, Fe: 0.10 wt.%, Zn: 6.55 wt.%, Zr: 0.10 wt.%, Mg(Zn,Cu,Al) 2 particles: 0.05 wt.%, rare earth high-entropy alloy particles: 0.10 wt.%, and the balance is Al; The composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials according to the ratio, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Perform homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then it is cooled to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong air cooling to perform online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Perform aging treatment on the aluminum alloy profile. The treatment temperature is 175 °C and the holding time is 8 h to obtain a 7-series aluminum alloy profile; The 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 2: A 7-series aluminum alloy profile, the 7-series aluminum alloy consists of the following weight percentages: Mg: 1.20 wt.%, Si: 0.085 wt.%, Cu: 0.24 wt.%, Mn: 0.025 wt.%, Cr: 0.025 wt.%, Ti: 0.025 wt.%, Fe: 0.19 wt.%, Zn: 6.65 wt.%, Zr: 0.15 wt.%, Mg(Zn,Cu,Al) 2 Particles: 0.05 wt.%, rare earth high-entropy alloy particles: 0.125 wt.%, the balance is Al; The composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare the metal raw materials according to the ratio, heat and melt them, filter them and pour them into the mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Carry out homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then it is cooled to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, and put the aluminum alloy bar into the extruder for extrusion. During the extrusion process, the head temperature of the bar is 510 °C, the tail temperature is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong air cooling to carry out online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Carry out aging treatment on the aluminum alloy profile. The treatment temperature is 175 °C and the holding time is 8 h to obtain a 7-series aluminum alloy profile; The 7-series aluminum alloy profile processed by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 3: A 7-series aluminum alloy profile, the 7-series aluminum alloy consists of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2Particles: 0.05 wt.%, Rare earth high-entropy alloy particles: 0.15 wt.%, the balance being Al; the composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7xxx series aluminum alloy profile includes the following steps: S1. Prepare the metal raw materials according to the ratio, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Perform homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong wind cooling to perform online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Perform aging treatment on the aluminum alloy profile. The treatment temperature is 175 °C and the holding time is 8 h to obtain a 7xxx series aluminum alloy profile; the 7xxx series aluminum alloy profile processed by the processing method of the 7xxx series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 4: A 7xxx series aluminum alloy profile, the 7xxx series aluminum alloy is composed of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 Particles: 0.05 wt.%, Rare earth high-entropy alloy particles: 0.15 wt.%, the balance being Al; the composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7xxx series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials according to the proportion, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Carry out homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.5 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong wind cooling to carry out on-line quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Carry out aging treatment on the aluminum alloy profile. The treatment temperature is 175 °C and the holding time is 8 h to obtain a 7-series aluminum alloy profile; The 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 5: A 7-series aluminum alloy profile, the 7-series aluminum alloy is composed of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 particles: 0.05 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, and the balance is Al; The components of the rare earth high-entropy alloy particles are La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials according to the proportion, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Carry out homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into the extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 3.0 m / s, and the outlet temperature is 515 °C to obtain the aluminum alloy bar; S4. Adopt strong wind cooling to perform online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain the aluminum alloy profile; S5. Perform aging treatment on the aluminum alloy profile at a treatment temperature of 175 °C and a holding time of 8 h to obtain the 7-series aluminum alloy profile; The 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 6: A 7-series aluminum alloy profile, the 7-series aluminum alloy consists of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 particles: 0.05 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, and the balance is Al; The composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare the metal raw materials according to the ratio, heat and melt them, filter them and pour them into the mold, add rare earth high-entropy alloy particles, hold at 640 °C for 20 min and stir well, and cool after the components are uniform to obtain the aluminum alloy ingot; S2. Perform homogenization treatment on the aluminum alloy ingot and hold it. The treatment temperature is 450 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into the extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain the aluminum alloy bar; S4. Adopt strong wind cooling to perform online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain the aluminum alloy profile; S5. Age the aluminum alloy profile at a treatment temperature of 175 °C for 8 h to obtain a 7-series aluminum alloy profile; the 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 7: A 7-series aluminum alloy profile, the 7-series aluminum alloy is composed of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 particles: 0.05 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, the balance is Al; the composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare the metal raw materials according to the ratio, heat and melt them, filter them and pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Carry out homogenization treatment on the aluminum alloy ingot and keep it warm, the treatment temperature is 460 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion, the temperature at the head of the bar during extrusion is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Take strong air cooling to carry out online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Age the aluminum alloy profile at a treatment temperature of 175 °C for 8 h to obtain a 7-series aluminum alloy profile; the 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 8: A 7xxx series aluminum alloy profile, the 7xxx series aluminum alloy consists of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 particles: 0.05 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, the balance is Al; the composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7xxx series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials according to the ratio, heat and melt them, filter them and pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Carry out homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 480 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then it is cooled to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong wind cooling to carry out online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Carry out aging treatment on the aluminum alloy profile. The treatment temperature is 175 °C and the holding time is 8 h to obtain a 7xxx series aluminum alloy profile; The 7xxx series aluminum alloy profile processed by the processing method of the 7xxx series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 9: A 7xxx series aluminum alloy profile, the 7xxx series aluminum alloy consists of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2Particles: 0.05 wt.%, Rare earth high-entropy alloy particles: 0.15 wt.%, the balance is Al; the composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare the metal raw materials according to the ratio, heat and melt them, filter them and pour them into the mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the composition is uniform to obtain an aluminum alloy ingot; S2. Carry out homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, and put the aluminum alloy bar into the extruder for extrusion. During the extrusion process, the temperature of the head of the bar is 510 °C, the temperature of the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong wind cooling to carry out online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Carry out aging treatment on the aluminum alloy profile. The treatment temperature is 180 °C and the holding time is 8 h to obtain a 7-series aluminum alloy profile; The 7-series aluminum alloy profile processed by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 10: A 7-series aluminum alloy profile, the 7-series aluminum alloy is composed of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 Particles: 0.05 wt.%, Rare earth high-entropy alloy particles: 0.15 wt.%, the balance is Al; the composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials in proportion, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the composition is uniform to obtain an aluminum alloy ingot; S2. Homogenize and keep the aluminum alloy ingot warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong air cooling to conduct online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Age the aluminum alloy profile. The treatment temperature is 175 °C and the holding time is 8 h to obtain a 7-series aluminum alloy profile; The 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 11: A 7-series aluminum alloy profile, the 7-series aluminum alloy is composed of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 Particles: 0.07 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, and the balance is Al; The composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials in proportion, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the composition is uniform to obtain an aluminum alloy ingot; S2. Homogenize and keep the aluminum alloy ingot warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. The die is preheated at 500°C, and the aluminum alloy rod is placed into an extruder for extrusion. During the extrusion process, the head temperature of the rod is 510°C, the tail temperature is 480°C, the extrusion rod speed is 2.0 m / s, and the outlet temperature is 515°C to obtain an aluminum alloy rod; S4. The extruded bar is subjected to online quenching treatment at a cooling rate of 200°C / min by strong wind cooling; S5. The quenched rod is straightened and sawed to obtain an aluminum alloy profile; S5. The aluminum alloy profile is subjected to aging treatment at a temperature of 175° C. and a heat preservation time of 8 hours to obtain a 7 series aluminum alloy profile; the 7 series aluminum alloy profile obtained by the processing method of the 7 series aluminum alloy profile is applied to lightweight aluminum alloy products for automobiles. Embodiment 12: A 7 series aluminum alloy profile, wherein the 7 series aluminum alloy is composed of the following weight percentages: Mg: 1.25wt.%, Si: 0.12wt.%, Cu: 0.28wt.%, Mn: 0.05wt.%, Cr: 0.05wt.%, Ti: 0.04wt.%, Fe: 0.28wt.%, Zn: 6.75wt.%, Zr: 0.20wt.%, Mg (Zn, Cu, Al) 2 Particles: 0.09wt.%, rare earth high entropy alloy particles: 0.15wt.%, the balance is Al; the composition of the rare earth high entropy alloy particles is La 20 Pr 20 G 20 Dy 20 Y 20 ; The processing method of the 7 series aluminum alloy profile comprises the following steps: S1. The metal raw materials are prepared in proportion, heated and melted, filtered and poured into a mold, rare earth high entropy alloy particles are added, kept at 640°C for 20 minutes and stirred thoroughly, cooled after the composition is uniform, and an aluminum alloy ingot is obtained; S2. The aluminum alloy ingot was homogenized and kept warm at a temperature of 470°C, a heating rate of 140°C / h, a holding time of 16h, and then cooled to room temperature at a cooling rate of 360°C / h; S3. The die is preheated at 500°C, and the aluminum alloy rod is placed into an extruder for extrusion. During the extrusion process, the head temperature of the rod is 510°C, the tail temperature is 480°C, the extrusion rod speed is 2.0 m / s, and the outlet temperature is 515°C to obtain an aluminum alloy rod; S4. The extruded bar is subjected to online quenching treatment at a cooling rate of 200°C / min by strong wind cooling; S5. The quenched rod is straightened and sawed to obtain an aluminum alloy profile; S5. Age the aluminum alloy profile at a treatment temperature of 175 °C for 8 h to obtain a 7-series aluminum alloy profile; the 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Example 13: A 7-series aluminum alloy profile, the 7-series aluminum alloy is composed of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 Particles: 0.12 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, and the balance is Al; the composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare the metal raw materials in proportion, heat and melt them, filter them and pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Carry out homogenization treatment on the aluminum alloy ingot and keep it warm, the treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion, the temperature at the head of the bar during extrusion is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong air cooling to carry out online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Age the aluminum alloy profile at a treatment temperature of 175 °C for 8 h to obtain a 7-series aluminum alloy profile; the 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. To further illustrate the technical effects of the present invention, the present invention also sets a comparative example, which is specifically as follows: Comparative Example 1: A 7xxx series aluminum alloy profile, the 7xxx series aluminum alloy consists of the following weight percentages: Mg: 1.15 wt.%, Si: 0.3 wt.%, Cu: 0.2 wt.%, Ti: 0.1 wt.%, Fe: 0.4 wt.%, Zn: 6.75 wt.%, Zr: 0.15 wt.%, Mg(Zn,Cu,Al) 2 particles: 0.05 wt.%, the balance is Al; The processing method of the 7xxx series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials according to the ratio, heat and melt them, filter them, pour them into a mold, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Homogenize the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong air cooling to perform online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Age the aluminum alloy profile. The treatment temperature is 185 °C and the holding time is 8 h to obtain a 7xxx series aluminum alloy profile; The 7xxx series aluminum alloy profile processed by the processing method of the 7xxx series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Comparative Example 2: A 7xxx series aluminum alloy profile, the 7xxx series aluminum alloy consists of the following weight percentages: Mg: 1.15 wt.%, Si: 0.3 wt.%, Cu: 0.2 wt.%, Ti: 0.1 wt.%, Fe: 0.4 wt.%, Zn: 6.75 wt.%, Zr: 0.15 wt.%, Mg(Zn,Cu,Al) 2 particles: 0.05 wt.%, the balance is Al; The composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7xxx series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials according to the proportion, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Perform homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 3.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong wind cooling to perform online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Perform aging treatment on the aluminum alloy profile. The treatment temperature is 175 °C and the holding time is 8 h to obtain a 7-series aluminum alloy profile; The 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Comparative Example 3: A 7-series aluminum alloy profile, the 7-series aluminum alloy is composed of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 Particles: 0.05 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, and the balance is Al; The components of the rare earth high-entropy alloy particles are La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials according to the proportion, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Perform homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 430 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. The die is preheated at 500°C, and the aluminum alloy rod is placed into an extruder for extrusion. During the extrusion process, the head temperature of the rod is 510°C, the tail temperature is 480°C, the extrusion rod speed is 2.0 m / s, and the outlet temperature is 515°C to obtain an aluminum alloy rod; S4. The extruded bar is subjected to online quenching treatment at a cooling rate of 200°C / min by strong wind cooling; S5. The quenched rod is straightened and sawed to obtain an aluminum alloy profile; S5. The aluminum alloy profile is subjected to aging treatment at a temperature of 175° C. and a heat preservation time of 8 hours to obtain a 7 series aluminum alloy profile; the 7 series aluminum alloy profile obtained by the processing method of the 7 series aluminum alloy profile is applied to lightweight aluminum alloy products for automobiles. Comparative Example 4: A 7 series aluminum alloy profile, wherein the 7 series aluminum alloy is composed of the following weight percentages: Mg: 1.25wt.%, Si: 0.12wt.%, Cu: 0.28wt.%, Mn: 0.05wt.%, Cr: 0.05wt.%, Ti: 0.04wt.%, Fe: 0.28wt.%, Zn: 6.75wt.%, Zr: 0.20wt.%, Mg (Zn, Cu, Al) 2 Particles: 0.05wt.%, rare earth high entropy alloy particles: 0.15wt.%, the balance is Al; the composition of the rare earth high entropy alloy particles is La 20 Pr 20 G 20 Dy 20 Y 20 ; The processing method of the 7 series aluminum alloy profile comprises the following steps: S1. The metal raw materials are prepared in proportion, heated and melted, filtered and poured into a mold, rare earth high entropy alloy particles are added, kept at 640°C for 20 minutes and stirred thoroughly, cooled after the composition is uniform, and an aluminum alloy ingot is obtained; S2. The aluminum alloy ingot was homogenized and kept warm at a temperature of 500°C, a heating rate of 140°C / h, a holding time of 16h, and then cooled to room temperature at a cooling rate of 360°C / h; S3. The die is preheated at 500°C, and the aluminum alloy rod is placed into an extruder for extrusion. During the extrusion process, the head temperature of the rod is 510°C, the tail temperature is 480°C, the extrusion rod speed is 2.0 m / s, and the outlet temperature is 515°C to obtain an aluminum alloy rod; S4. The extruded bar is subjected to online quenching treatment at a cooling rate of 200°C / min by strong wind cooling; S5. The quenched rod is straightened and sawed to obtain an aluminum alloy profile; S5. Age the aluminum alloy profile at a treatment temperature of 175 °C for 8 h to obtain a 7-series aluminum alloy profile; the 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Comparative Example 5: A 7-series aluminum alloy profile, the 7-series aluminum alloy is composed of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 Particles: 0.05 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, and the balance is Al; the composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7-series aluminum alloy profile includes the following steps: S1. Prepare metal raw materials in proportion, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Perform homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then it is cooled to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion. During the extrusion process, the head temperature of the bar is 510 °C, the tail temperature is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong air cooling to perform online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Age the aluminum alloy profile at a treatment temperature of 160 °C for 8 h to obtain a 7-series aluminum alloy profile; the 7-series aluminum alloy profile obtained by the processing method of the 7-series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Comparative Example 6: A 7xxx series aluminum alloy profile, the 7xxx series aluminum alloy consists of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, Mg(Zn,Cu,Al) 2 Particles: 0.05 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, the balance is Al; the composition of the rare earth high-entropy alloy particles is La 20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7xxx series aluminum alloy profile includes the following steps: S1. Prepare the metal raw materials according to the ratio, heat and melt them, filter them and pour them into the mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Carry out homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then it is cooled to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into the extruder for extrusion. During the extrusion process, the temperature of the head of the bar is 510 °C, the temperature of the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong air cooling to carry out on-line quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain an aluminum alloy profile; S5. Carry out aging treatment on the aluminum alloy profile. The treatment temperature is 200 °C and the holding time is 8 h to obtain a 7xxx series aluminum alloy profile; the 7xxx series aluminum alloy profile processed by the processing method of the 7xxx series aluminum alloy profile is applied to automotive lightweight aluminum alloy products. Comparative Example 7: A 7xxx series aluminum alloy profile, the 7xxx series aluminum alloy consists of the following weight percentages: Mg: 1.25 wt.%, Si: 0.12 wt.%, Cu: 0.28 wt.%, Mn: 0.05 wt.%, Cr: 0.05 wt.%, Ti: 0.04 wt.%, Fe: 0.28 wt.%, Zn: 6.75 wt.%, Zr: 0.20 wt.%, rare earth high-entropy alloy particles: 0.15 wt.%, the balance is Al; The composition of the rare earth high-entropy alloy particles is La20 Pr 20 Gd 20 Dy 20 Y 20 ; The processing method of the 7xxx series aluminum alloy profiles includes the following steps: S1. Prepare metal raw materials in proportion, heat and melt them, filter them, pour them into a mold, add rare earth high-entropy alloy particles, keep them at 640 °C for 20 min and stir well, and cool them after the components are uniform to obtain an aluminum alloy ingot; S2. Perform homogenization treatment on the aluminum alloy ingot and keep it warm. The treatment temperature is 470 °C, the heating rate is 140 °C / h, the holding time is 16 h, and then cool it to room temperature at a cooling rate of 360 °C / h; S3. Preheat the mold at 500 °C, put the aluminum alloy bar into an extruder for extrusion. During the extrusion process, the temperature at the head of the bar is 510 °C, the temperature at the tail is 480 °C, the speed of the extrusion rod is 2.0 m / s, and the outlet temperature is 515 °C to obtain an aluminum alloy bar; S4. Adopt strong air cooling to perform online quenching treatment on the extruded bar at a cooling rate of 200 °C / min; S5. Straighten and saw the quenched bar to obtain aluminum alloy profiles; S5. Perform aging treatment on the aluminum alloy profiles. The treatment temperature is 175 °C and the holding time is 8 h to obtain 7xxx series aluminum alloy profiles; The 7xxx series aluminum alloy profiles processed by the processing method of the 7xxx series aluminum alloy profiles are applied to automotive lightweight aluminum alloy products. Referring to the GB / T 16865-2013 standard, a universal testing machine is used to perform tensile tests on each example and comparative example. The tensile specimen is dumbbell-shaped, the effective test part is cylindrical, and the tensile rate is 0.5 mm / min; And perform extrusion rod speed tests on the alloy profiles; The test results are shown in Tables 1 to 5. Table 1 Influence of different rare earth high-entropy alloy particle contents on the mechanical properties of the alloy Table 2 Test results of extrusion rod speeds of alloys with different compositions Table 3 Influence of different homogenization treatment temperatures on the mechanical properties of the alloy Table 4 Influence of different aging treatment temperatures on the mechanical properties of the alloy Table 5 Influence of different second-phase particle contents on the mechanical properties of the alloy In summary, for each embodiment of the present invention, the tensile strength of the aluminum alloy profile is above 420 MPa, the yield strength is above 390 MPa, the speed of the extrusion rod can reach 3.0 mm / s, and at the same time, the inner cavity of the profile does not crack. Compared with Comparative Example 2 where the inner cavity of the profile cracks when the speed of the extrusion rod is 2.5 mm / s, the service life of the die is increased by 50%, effectively reducing the production cost.

Claims

1. A 7 series aluminum alloy profile, characterized in that: The 7 series aluminum alloy is composed of the following weight percentages: Mg: 1.15~1.26wt.%, Si: 0.05~0.12wt.%, Cu: 0.2~0.28wt.%, Mn: ≤0.05wt.%, Cr: ≤0.05wt.%, Ti: 0.01~0.04wt.%, Fe: 0.1~0.28wt.%, Zn: 6.55~6.75wt.%, Zr: 0.1~0.2wt.%, Mg(Zn,Cu,Al)2 particles: 0.05~0.12wt.%, rare earth high entropy alloy particles: 0.1~0.15wt.%, and the balance is Al.

2. The 7 series aluminum alloy profile according to claim 1, characterized in that: The composition of the rare earth high entropy alloy particles is La 15-25 Pr 15-25 G 15-25 Dy 15-25 Y 15-25 .

3. The processing method of 7 series aluminum alloy profile according to claim 1, characterized in that: The following steps are involved: S1. The metal raw materials are prepared in proportion, heated and melted, filtered and poured into a mold, rare earth high entropy alloy particles are added, kept warm and stirred thoroughly, and cooled after the composition is uniform to obtain an aluminum alloy ingot; S2. homogenizing and keeping the aluminum alloy ingot warm, and then cooling it at a cooling rate of ≥200°C / h; S3. Preheating the mold and placing the aluminum alloy rod into an extruder for extrusion to obtain an aluminum alloy rod; S4. The extruded bar is subjected to online quenching treatment at a cooling rate of ≥200°C / min; S5. The quenched rod is straightened and sawed to obtain an aluminum alloy profile; S6. Performing aging treatment on the aluminum alloy profile to obtain a 7 series aluminum alloy profile.

4. The method for processing 7 series aluminum alloy profiles according to claim 3, characterized in that: In step S1, the alloy melt is kept at a temperature of 620-660° C. for a time of 15-25 minutes.

5. The method for processing 7 series aluminum alloy profiles according to claim 3, characterized in that: The treatment temperature in step S2 is 450-480° C., the heating rate is 80-230° C. / h, and the insulation time is 5-20 h.

6. The method for processing 7 series aluminum alloy profiles according to claim 3, characterized in that: In step S3, the mold preheating temperature is 485-505°C, the temperature of the rod head is 500-515°C, the temperature of the tail is 460-480°C, the extrusion rod speed is 1.5-3.0 m / s, and the outlet temperature is 500-520°C.

7. The method for processing 7 series aluminum alloy profiles according to claim 3, characterized in that: The online quenching treatment method in step S4 includes any one of strong wind cooling, water mist cooling, spray cooling and water cooling.

8. The method for processing 7 series aluminum alloy profiles according to claim 3, characterized in that: The aging treatment temperature in step S6 is 170-190° C., and the insulation time is 6-12 hours.

9. The 7 series aluminum alloy profile processed by the processing method of the 7 series aluminum alloy profile according to claims 1 to 8 is applied to lightweight aluminum alloy products for automobiles.

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