CN114774747A - High-strength 7000 series aluminum alloy section and processing and preparation method thereof - Google Patents

Abstract

The invention provides a high-strength 7000 series aluminum alloy profile which comprises the following components in percentage by weight: zn: 7.5-7.65%, Mg: 1.5-1.7%, Cu: 0.16-0.2%, Zr: 0.17-0.2%, Fe: 0.04-0.06%, Si: 0.01-0.05% and the balance of Al. The aluminum alloy section has the characteristics of high Zn/Mg ratio and low Cu content. The invention also provides a preparation method of the high-strength 7000 series aluminum alloy section, and the novel high-strength 7000 series aluminum alloy with uniform structure and excellent mechanical property is obtained through alloy component regulation and two-stage aging treatment.

Description

A kind of high-strength 7000 series aluminum alloy profile and its processing and preparation method

technical field

The invention relates to the technical field of aluminum alloy material forming, in particular to a high-strength 7000 series aluminum alloy profile and a processing and preparation method thereof.

Background technique

7000 series aluminum alloys have high specific strength, high specific stiffness, and excellent fracture toughness and fatigue resistance. In addition, 7000 series aluminum alloys have good hot workability and corrosion resistance, so they are widely used in aerospace. , vehicles, buildings, bridges and large pressure vessels and other fields.

In 7000 series aluminum alloys, the main strengthening elements are Zn and Mg, which can form strengthening phases η phase (MgZn ₂ ) and T phase (Al ₂ Mg3Zn ₃ ) in the alloy. When the mass fraction of Zn is 7-12%, the mass fraction of Mg is 2-3%, and the mass ratio of Zn to Mg is greater than or equal to 3, Zn and Mg mainly form η phase in the alloy. With the increase of Zn and Mg content, the amount of strengthening increases to improve the strength of the alloy; when the atomic ratio of Zn and Mg is close to the T phase, the overall performance of the alloy is the best. The 7000 series aluminum alloy also contains Cu. In the equilibrium state, the solid solution limit of Cu in the Al matrix is 5.56%. When the Cu content is high and the Mg content is low, the alloy forms theta phase (Al ₂ Cu). Cu can effectively improve the dispersion degree of the precipitation phase. By increasing the Cu content in the precipitation phase at the grain boundary and reducing the potential difference between the grain boundary and the grain, the stress corrosion cracking tendency of the alloy can be reduced. However, when the Zn and Mg contents are relatively small, the higher the Cu content, the worse the alloy toughness.

7000 series aluminum alloys belong to heat-treatable strengthening alloys, mainly through the precipitation of supersaturated solid solution, to precipitate a large number of fine and dispersed second-phase particles to achieve the purpose of strengthening, namely effect strengthening, also known as precipitation strengthening. The aging precipitation sequence of 7000 series aluminum alloy is: supersaturated solid solution → solute atom segregation region (GP region) → metastable phase η' → equilibrium phase η. In the early stage of aging, the precipitated phase is the GP region. With the increase of the aging temperature or the prolongation of the holding time, the metastable phase η' semi-coherent with the Al matrix is formed with the GP region as the core. Both the GP region and the metastable phase η' can strengthen the alloy, and the η' phase plays a major role in strengthening. The η' phase is easy to nucleate and grow at dislocations and grain boundaries, and its strengthening effect on the alloy is affected by the degree of coherence and uniformity. The η' phase can act as the nucleus of the equilibrium phase η that is incompatible with the Al matrix, and the alloy strength begins to decrease with the formation and growth of the η phase.

The prior art discloses an Al-Zn-Mg-Cu series ultra-high-strength aluminum alloy and a preparation method. High hardenability; and through the development of a multi-stage heat treatment process with double cryogenic embedding on the traditional heat treatment process, the distribution state of the strengthening phase is adjusted. The aluminum alloy needs to be processed by a multi-stage heat treatment process of double cryogenic embedding, the process is slightly complicated, and the toughness and elongation properties of the alloy need to be improved.

SUMMARY OF THE INVENTION

In order to solve the above problems existing in the prior art, the present invention provides a high-strength 7000 series aluminum alloy profile, which has the characteristics of high Zn/Mg ratio and low Cu content; the present invention also provides the high-strength 7000 series aluminum alloy profile. The preparation method of aluminum alloy profiles, through the control of alloy composition and double-stage aging treatment, obtains a new high-strength 7000 series aluminum alloy with uniform structure and excellent mechanical properties.

In order to achieve the above object, the present invention provides the following technical solutions:

A high-strength 7000 series aluminum alloy profile, by weight percentage, includes the following components:

Zn: 7.5-7.65%,

Mg: 1.5-1.7%,

Cu: 0.16-0.2%,

Zr: 0.17-0.2%,

Fe: 0.04-0.06%,

Si: 0.01-0.05%,

The remainder is Al.

As a preferred technical solution of the present invention, a high-strength 7000 series aluminum alloy profile, by weight percentage, includes the following components:

Zn: 7.65%,

Mg: 1.57%,

Cu: 0.16%,

Zr: 0.17%,

Fe: 0.05%,

Si: 0.03%,

The remainder is Al.

The present invention provides a method for processing and preparing the above-mentioned high-strength 7000 series aluminum alloy profiles, which comprises the following steps:

S1. Material preparation: prepare raw material pure aluminum ingot, pure zinc ingot and master alloy Al-50Mg, Al-50Cu, Al-10Zr and refiner Al-5Ti-1B;

S2. Alloy smelting: first preheat to 200°C, then add pure aluminum ingot and master alloy Al-50Cu, heat up and melt, and then add pure zinc ingot, master alloy Al-50Mg and Al-10Zr in sequence at 720-725°C, Among them, the temperature is kept for 10 minutes after each feeding; refining is carried out at 718-722 °C, and the slag is removed after standing for 10 minutes. Finally, the refining agent Al-5Ti-1B is added and poured at 710-720 °C;

S3. Alloy ingot and homogenization treatment: ingot the alloy obtained by casting S2, the alloy homogenization treatment temperature is 470 ℃, the holding time is 24h, and air cooling; The preheating temperature is 430°C and 450°C respectively, and the holding time is 1h; the preheating temperature of punch and extrusion cylinder is 400°C, and the holding time is 1h; the hot extrusion rate is V=2mm/s, The extrusion ratio is 39.4;

S4. Hot extrusion: the solution treatment temperature of the hot extrusion bar is 470 °C, the holding time is 1 h, and the water quenching is completed after the thermal insulation is completed;

S5. Artificial aging: artificial aging is performed after solution treatment.

Further, the artificial aging is a two-stage aging process, and the two-stage aging process conditions are respectively 120°C/6h+160°C/(8, 10, 12, 14, 16h), and 120°C/6h+180°C /(8, 10, 12, 14, 16h).

Double-stage aging usually refers to the first-stage low-temperature aging + the second-stage high-temperature aging. Among them, after the first-stage low-temperature aging, a large number of fine and evenly distributed GP regions are precipitated in the alloy; then after entering the second-stage high-temperature aging, the GP region transforms to η' phase. By changing the two-stage aging process, that is, controlling the aging temperature and aging time, the density, morphology, size, etc. of the precipitates in the alloy grain and at the grain boundary can be effectively improved, thereby improving the mechanical properties of the alloy.

As a further description of the technical solution of the present invention, the added master alloy Al-50Mg is 3-3.4% of the total weight of the raw materials; the added master alloy Al-50Cu is 0.32-0.4% of the total raw material weight; the added master alloy Al-10Zr 1.7-2% of the master alloy.

As a further description of the technical solution of the present invention, the purity of the pure aluminum ingot is above 99.85%.

As a further description of the technical solution of the present invention, in the S2, the refining agent used in refining is hexachloroethane.

As a further description of the technical solution of the present invention, in the master alloy Al-50Mg, the content of Mg is 50% of the total weight of the master alloy.

As a further description of the technical solution of the present invention, in the master alloy Al-50Cu, the content of Cu is 50% of the total weight of the master alloy; in the master alloy Al-10Zr, the content of Zr is 10% of the total weight of the master alloy.

As a further description of the technical solution of the present invention, in the refiner Al-5Ti-1B, the content of Ti is 5% of the total weight of the master alloy, and the content of B is 1% of the total weight of the Zhongjie alloy.

Based on the above-mentioned technical scheme, compared with the prior art, the present invention has the following advantages and beneficial effects:

In the high-strength 7000 series aluminum alloy profiles provided by the invention, the main alloy elements are adjusted and other components of the alloy are optimized, so that the components of the alloy have the characteristics of high Zn/Mg ratio and low Cu content, and the mechanical properties of the alloy are improved by adjusting the alloy components. performance. In addition, the processing and preparation method of the high-strength 7000 series aluminum alloy profile provided by the present invention also improves the formability of the alloy by regulating the extrusion process, and adopts two-stage aging to regulate the precipitation phase, which further improves the mechanical properties of the alloy.

Description of drawings

FIG. 1 is a microstructure diagram of the extruded alloy bar of Example 1 under a double-stage aging process of 120° C./6h+160° C./12h.

FIG. 2 is a microstructure diagram of the extruded alloy bar of Example 1 under a double-stage aging process of 120°C/6h+180°C/12h.

3 is a graph showing the tensile strength of the extruded alloy bar of Example 1 under different double-stage aging processes.

4 is a graph showing the elongation rate of the extruded alloy bar of Example 1 under different double-stage aging processes.

5 is a graph showing the Vickers hardness of the extruded alloy bar of Example 1 under different double-stage aging processes.

FIG. 6 is the tensile fracture morphologies of the extruded alloy bars of Example 1 under different double-stage aging processes.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings and specific embodiments. The present invention provides the preferred embodiment. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the present disclosure is provided.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

A high-strength 7000 series aluminum alloy profile, by weight percentage, includes the following components:

Zn: 7.5-7.65%, Mg: 1.5-1.7%, Cu: 0.16-0.2%, Zr: 0.17-0.2%, Fe: 0.04-0.06%, Si: 0.01-0.05%, and the balance is Al.

The above-mentioned high-strength 7000 series aluminum alloy profile is prepared by the following processing and preparation method, and the processing and preparation method specifically includes the following steps:

S1. Material preparation: prepare raw material pure aluminum ingot, pure zinc ingot and master alloy Al-50Mg, Al-50Cu, Al-10Zr and refiner Al-5Ti-1B;

S2. Alloy smelting: first preheat to 200°C, then add pure aluminum ingot and master alloy Al-50Cu, heat up and melt, and then add pure zinc ingot, master alloy Al-50Mg and Al-10Zr in sequence at 720-725°C, In which, after each feeding, the temperature is kept for 10 minutes; the refining agent hexachloroethane is added at 718-722 °C for refining, and the slag is removed after standing for 10 minutes. Finally, the refining agent Al-5Ti-1B is added, and it is poured at 710-720 °C;

S3. Alloy ingot and homogenization treatment: ingot the alloy obtained by casting S2, the alloy homogenization treatment temperature is 470 ℃, the holding time is 24h, and air cooling; The preheating temperature is 430°C and 450°C respectively, and the holding time is 1h; the preheating temperature of punch and extrusion cylinder is 400°C, and the holding time is 1h; the hot extrusion rate is V=2mm/s, The extrusion ratio is 39.4;

S4. Hot extrusion: the solution treatment temperature of the hot extrusion bar is 470 °C, the holding time is 1 h, and the water quenching is completed after the thermal insulation is completed;

S5. Artificial aging: artificial aging is carried out after solution treatment, and the two-stage aging process is 120℃/6h+160℃/(8, 10, 12, 14, 16h) and 120℃/6h+180℃/(8 , 10, 12, 14, 16h).

Among them, the added intermediate alloys Al-50Mg, Al-50Cu and Al-10Zr are respectively 3-3.4%, 0.32-0.4% and 1.7-2% of the total weight of the raw materials; the purity of the pure aluminum ingot is above 99.85%.

Example 1

The aluminum alloy provided in this embodiment is an aluminum alloy ingot prepared by gravity casting, and the aluminum alloy ingot is a high-strength 7000 series aluminum alloy profile, and its chemical composition is shown in Table 1.

Table 1 Chemical composition (wt.%) of the high-strength 7000 series aluminum alloy profile of Example 1

Zn Mg Cu Zr Fe Si Al 7.65 1.57 0.16 0.17 0.05 0.03 90.37

The alloy smelting adopts the method of gravity casting, and the raw materials used are pure aluminum ingot (purity 99.85%), pure zinc ingot (purity 99.9%) and intermediate alloys Al-50Mg, Al-50Cu, Al-10Zr and refiner Al- 5Ti-1B.

In the master alloy Al-50Mg, the content of Mg is 50% of the total weight of the master alloy;

In the master alloy Al-50Cu, the content of Cu is 50% of the total weight of the master alloy;

In the master alloy Al-10Zr, the content of Zr is 10% of the total weight of the master alloy;

In the refiner Al-5Ti-1B, the content of Ti is 5% of the total weight of the master alloy, and the content of B is 1% of the total weight of the Zhongjie alloy.

In the alloy smelting process, the burning loss rate of aluminum is calculated as 3%, and the burning loss rate of magnesium is calculated as 15%.

First, the graphite crucible was preheated to 200°C in a resistance furnace, and then pure aluminum ingots and intermediate alloy Al-50Cu were added to heat up and melt. Pure zinc ingot, intermediate alloy Al-10Zr and intermediate Al-50Mg were added in sequence at a temperature of 720-725°C, and the temperature was kept for 10 minutes after each addition. Refining is carried out at about 720 ℃, and after standing for 10 minutes, the slag is removed, and the refining agent hexachloroethane is added for refining. Then add the refiner Al-5Ti-1B, and pour it at 710-720℃ to obtain an alloy ingot of 55mm×165mm.

In the process of adding the master alloy, the addition amounts of Al-50Mg, Al-50Cu and Al-10Zr are 3.2%, 0.36% and 1.8% of the total weight of the raw materials, respectively.

The homogenization of the alloy ingot is carried out in a box-type resistance furnace, and the accuracy of controlling the furnace temperature is ±1 °C. First, the temperature in the furnace was raised to the set temperature at a heating rate of 10°C/min. After the temperature was stable, the alloy ingot was put into it. The homogenization temperature of the alloy ingot is 470℃, the holding time is 24h, and the air cooling is performed.

The alloy ingot after the homogenization treatment was processed into a cylinder of 50 mm × 35 mm as a hot extrusion billet. The hot extrusion process adopts the way of positive extrusion, which is carried out on a 2000KN vertical extruder.

The designed hole diameter of the die is 6mm, the corresponding extrusion ratio is 69.4, and the die material is H13 steel. Before hot extrusion, the extruded billet and die were preheated in a box-type resistance furnace. The preheating temperatures were 430°C and 450°C, respectively, and the holding time was 1 h. At the same time, the heating ring was turned on to preheat the extrusion cylinder and the punch, the preheating temperature was 400°C, and the holding time was 1h.

During hot extrusion, first raise the punch, put the die into the extrusion cylinder, apply lubricant (a mixture of No. 45 engine oil and 30-40% flake graphite), and then put the extrusion blank quickly. Into the extrusion cylinder, the punch moves downward at the rate of V=2mm/s, and the hot extrusion deformation process is started.

The hot-extruded bar is heat-treated in a box-type resistance furnace. The solution treatment temperature is 470°C, and the holding time is 1h. After the heat preservation is completed, water quenching.

Artificial aging is carried out after solution treatment, and the two-stage aging process is 120℃/6h+160℃/(8, 10, 12, 14, 16h) and 120℃/6h+180℃/(8, 10, 12, 14 , 16h).

The tensile samples were cut along the length direction of the alloy bars and completed on an electronic universal material testing machine with a tensile rate of 2 mm/min. According to the national standard GB/T 228-2002, the size of the gauge area of the sample is φ4×28mm, and the measured mechanical property data is the average value of 3 standard samples.

The microhardness test sample is the longitudinal section of the sample, and a digital microhardness tester is used for the hardness test. The test loading load is 1.96N, and the loading time is 15s. Five points were selected for each sample, and the distance between the points was greater than 0.5 mm, and the average value was taken as the microhardness result.

Figure 1 is the microstructure of the extruded alloy bar of this embodiment under the double-stage aging process of 120°C/6h+160°C/12h. After double-stage aging, the precipitation phase of the alloy bar is round or oval, and the size is larger, 80-200nm. .

Figure 2 is the microstructure diagram of the extruded alloy bar of this embodiment under the double-stage aging process of 120°C/6h+180°C/12h. After stage aging, the density of precipitates decreases significantly.

Fig. 3 is a graph showing the tensile strength of the extruded alloy bar of this embodiment under different double-stage aging processes, and Fig. 4 is an elongation curve of the extruded alloy bar of this embodiment under different double-stage aging processes picture. As shown in Figures 3 and 4, the tensile strength and elongation of the extruded alloy bar after first-order aging at 120°C/6h were 707.8MPa and 8.9%, respectively.

After secondary aging at 160°C/8h, the tensile strength decreased to 651MPa, while the elongation increased significantly to 12.7%; when the secondary aging time was ≥12h, the tensile strength did not change much and remained at about 630MPa; When the secondary aging time is more than 8h, the elongation is less affected by the aging time and is maintained at about 12.5%

After secondary aging at 180℃/8h, the tensile strength decreased to 572.8MPa, and the elongation increased slightly to 10.2%. When the secondary aging time is ≥14h, the tensile strength is stable at about 540MPa; when the secondary aging time is ≥14h, the elongation is stable at about 14.2%.

FIG. 5 is a graph showing the Vickers hardness of the extruded alloy bars of the present embodiment under different double-stage aging processes. As shown in Fig. 5, when the secondary aging is 160℃/8～12h, with the increase of aging time, the microhardness of the alloy gradually decreases, from 8h/164.5HV to 12h/155.4HV, and then with the aging With the increase of time, the microhardness of the alloy gradually increases. When the secondary aging time is 16h, the microhardness rises back to 162.4HV, but as a whole, under the double-stage aging of 120℃/6h+160℃/-h, the aging Time has little effect on the microhardness of the alloy.

When the secondary aging is 180℃/8h～12h, with the increase of aging time, the microhardness of the alloy gradually decreases, from 8h/141.3HV to 12h/115.8HV, and then when the aging time ≥ 12h, the microhardness of the alloy decreases. The hardness is stable at around 120HV.

Fig. 6 is the tensile fracture morphologies of the extruded alloy bars of the present embodiment under different double-stage aging processes, wherein (a) the double-stage aging conditions are 120°C/6h+160°C/8h; (b) ), the double-stage aging condition is 120℃/6h+160℃/12h; (c), the double-stage aging condition is 120℃/6h+180℃/8h; (d), the double-stage aging condition is 120℃/6h+ 180°C/12h. As shown in Fig. 6, there are a large number of dimples in the fractures of the tensile specimens, indicating that the alloys have ductile fractures under the two double-stage aging regimes. When the secondary aging is 180℃/12h(d), the size of the dimples in the fracture of the alloy increases significantly, which indicates that the alloy will undergo larger plastic deformation during the tensile fracture process and obtain higher elongation in this state.

It can be seen that compared with the double-stage aging at 180 °C, the extruded bar can obtain better comprehensive mechanical properties under the double-stage aging with the second-stage aging temperature of 160 °C.

Example 2

The aluminum alloy provided in this embodiment is an aluminum alloy ingot prepared by gravity casting, and the aluminum alloy ingot is a high-strength 7000 series aluminum alloy profile, and its chemical composition is shown in Table 2.

Table 2 Chemical composition (wt.%) of the high-strength 7000 series aluminum alloy profile of Example 2

Zn Mg Cu Zr Fe Si Al 7.5 1.5 0.16 0.17 0.04 0.05 90.58

The alloy is smelted by gravity casting, and the raw materials used are pure aluminum ingot (99.85% purity), pure zinc ingot and intermediate alloys Al-50Mg, Al-50Cu, Al-10Zr and refiner Al-5Ti-1B.

The preparation method of the high-strength 7000 series aluminum alloy profile in this embodiment is the same as that in Embodiment 1.

Example 3

The aluminum alloy provided in this embodiment is an aluminum alloy ingot prepared by gravity casting, and the aluminum alloy ingot is a high-strength 7000 series aluminum alloy profile, and its chemical composition is shown in Table 2.

Table 3 Chemical composition (wt.%) of the high-strength 7000 series aluminum alloy profile of Example 3

Zn Mg Cu Zr Fe Si Al 7.6 1.7 0.2 0.2 0.06 0.01 90.19

The alloy is smelted by gravity casting, and the raw materials used are pure aluminum ingot (99.85% purity), pure zinc ingot and intermediate alloys Al-50Mg, Al-50Cu, Al-10Zr and refiner Al-5Ti-1B.

The preparation method of the high-strength 7000 series aluminum alloy profile in this embodiment is the same as that in Embodiment 1.

Example 4

The aluminum alloy provided in this embodiment is an aluminum alloy ingot prepared by gravity casting, and the aluminum alloy ingot is a high-strength 7000 series aluminum alloy profile, and its chemical composition is shown in Table 2.

Table 4 Chemical composition (wt.%) of the high-strength 7000 series aluminum alloy profile of Example 4

Zn Mg Cu Zr Fe Si Al 7.65 1.6 0.18 0.18 0.05 0.03 90.31

The alloy is smelted by gravity casting, and the raw materials used are pure aluminum ingot (99.85% purity), pure zinc ingot and intermediate alloys Al-50Mg, Al-50Cu, Al-10Zr and refiner Al-5Ti-1B.

The preparation method of the high-strength 7000 series aluminum alloy profile in this embodiment is the same as that in Embodiment 1.

The alloy samples of the high-strength 7000 series aluminum alloy profiles prepared in Examples 1 to 4 were taken for mechanical property testing, and the results are shown in Table 5.

Table 5 Performance test table of high-strength 7000 series aluminum alloy profiles of Example 1-Example 4

Example 1 Example 2 Example 3 Example 4 Tensile strength (MPa) 651 663 632 647 Yield Strength (MPa) 640 649 621 636 Elongation (%) 12.7 12.1 13.2 12.8

The above contents are only examples and descriptions of the present invention, and the descriptions thereof are more specific and detailed, but should not be construed as limiting the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, some modifications and improvements can be made without departing from the concept of the present invention, and these obvious alternative forms all belong to the protection scope of the present invention.

Claims (10)

1. The high-strength 7000 series aluminum alloy section is characterized by comprising the following components in percentage by weight:

Zn：7.5-7.65％，

Mg：1.5-1.7％，

Cu：0.16-0.2％，

Zr：0.17-0.2％，

Fe：0.04-0.06％，

Si：0.01-0.05％，

the balance being Al.

2. The high-strength 7000 series aluminum alloy profile is characterized by comprising the following components in percentage by weight: zn: 7.65 percent of the total weight of the mixture,

Mg：1.57％，

Cu：0.16％，

Zr：0.17％，

Fe：0.05％，

Si：0.03％，

the balance being Al.

3. A method of producing a high strength 7000-series aluminium alloy profile according to any one of claims 1-2, comprising the steps of:

s1, material preparation: preparing raw materials of pure aluminum ingots, pure zinc ingots, intermediate alloy Al-50Mg, Al-50Cu, Al-10Zr and refiner Al-5 Ti-1B;

s2, alloy smelting: preheating to 200 ℃, adding a pure aluminum ingot and an intermediate alloy Al-50Cu, heating to melt, sequentially adding a pure zinc ingot, an intermediate alloy Al-50Mg and Al-10Zr at 720-725 ℃, and keeping the temperature for 10min after each charging; refining at 718-;

s3, alloy ingot casting and homogenization treatment: casting the alloy obtained by casting in S2, homogenizing the alloy at 470 ℃ for 24h, and cooling in air; preheating an extrusion blank and a female die at the preheating temperatures of 430 ℃ and 450 ℃ respectively for 1h before hot extrusion; preheating the male die and the extrusion container at 400 ℃, and keeping the temperature for 1 h; the hot extrusion rate is V2 mm/s, and the extrusion ratio is 39.4;

s4, hot extrusion molding: the solution treatment temperature of the hot extrusion molding bar is 470 ℃, the heat preservation time is 1h, and water quenching is carried out after the heat preservation is finished;

s5, artificial aging: and carrying out artificial aging after the solution treatment.

4. The processing preparation method according to claim 3, wherein the artificial aging is a double-stage aging process, and the conditions of the double-stage aging process are 120 ℃/6h +160 ℃/(8, 10, 12, 14, 16h) and 120 ℃/6h +180 ℃/(8, 10, 12, 14, 16h), respectively.

5. The processing and preparation method of claim 4, wherein the added master alloy Al-50Mg accounts for 3-3.4% of the total weight of the raw materials; the added master alloy Al-50Cu accounts for 0.32-0.4% of the total weight of the raw materials; the added intermediate alloy Al-10Zr accounts for 1.7-2% of the intermediate alloy.

6. The process of claim 5, wherein the purity of said ingot is greater than 99.85%.

7. The process according to claim 6, wherein in S2, the refining agent used in refining is hexachloroethane.

8. The process of claim 7, wherein the amount of Mg in the master alloy Al-50Mg is 50% of the total weight of the master alloy.

9. The process of claim 8, wherein in the master alloy Al-50Cu, the content of Cu is 50% of the total weight of the master alloy; in the intermediate alloy Al-10Zr, the content of Zr is 10 percent of the total weight of the intermediate alloy.

10. The process according to claim 9, wherein in the refiner Al-5Ti-1B, Ti is present in an amount of 5% by weight of the total weight of the master alloy and B is present in an amount of 1% by weight of the total weight of the master alloy.

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