Aluminum alloy bar and multistage temperature control preparation method and application thereof

Abstract

The invention discloses an aluminum alloy bar as well as a multistage temperature control preparation method and application thereof, and belongs to the technical field of alloys. The aluminum alloy bar comprises the following components in percentage by weight: 1.3%-1.5% of Si, 1.5%-1.6% of Fe, 2.7%-2.9% of Cu, 1.9%-2.1% of Mg, less than or equal to 0.1% of Ti, 1.5%-1.7% of Ni, 0.1%-0.2% of Mn, less than or equal to 0.1% of Cr, 0.05%-0.15% of Zn and the balance of Al. The single impurity is less than or equal to 0.05%, the total impurity is less than or equal to 0.1% and the balance is Al, and the total percentage is 100%. The aluminum alloy bar is fine and uniform in grain distribution, the tensile strength is larger than or equal to 430 MPa, the yield strength is larger than or equal to 300 MPa, and the ductility is larger than or equal to 16.0%.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and in particular to an aluminum alloy bar and a multi-stage temperature-controlled preparation method and application thereof. Background Art

[0002] The AlCuMg, AlFeNi, MgSi and other phases present in Al-Cu-Mg-Fe-Ni aluminum alloy make the alloy's mechanical properties and oxidation resistance not significantly reduced after working for a certain period of time under high temperature and stress conditions, and it also has good high temperature resistance and high specific strength. It has been widely used in weapons, automobiles and aerospace industries. With the rapid development of society, more stringent requirements have been put forward for the heat resistance of aluminum alloys. At present, the Al-Cu-Mg-Fe-Ni aluminum alloy bars produced domestically generally have uneven grain structure and low performance, which not only reduces the yield of the alloy bars and increases the manufacturing cost, but also seriously affects its application in the field of national defense and military industry.

[0003] The prior art discloses a preparation method capable of eliminating the coarse crystal ring of 2219 aluminum alloy extruded rod. The alloy comprises the following components by mass percentage: Cu 5.8-6.8%, Mn 0.30-0.40%, V 0.05-0.15%, Ti 0.02-0.10%, Zr 0.20-0.25%, Si≤0.2%, Fe≤0.3%, Mg≤0.02%, Zn≤0.10%, and the rest are Al and inevitable impurity elements. The purpose of eliminating the coarse crystal ring of the alloy is achieved by improving the metallurgical quality of the alloy ingot and adjusting the extrusion process. However, the heating and heat preservation time in the heating furnace of the technology reaches 10-30 hours, and the extruded rod needs to be cooled by online water mist, which not only causes a waste of energy but also has high requirements on the conditions of the extrusion equipment.

[0004] The prior art discloses a high-strength aluminum alloy bar material for automobile control arms without coarse grain rings and a preparation method thereof. The mass percentage of the alloy components is: Si 0.9% to 1.2%, Fe 0.3%, Cu 0.15% to 0.2%, Mn 0.4% to 0.6%, Mg 0.7%, Cr 0.17% to 0.25%, Zn 0.15%, Zr 0.02% to 0.04%, and the balance is Al. The purpose of eliminating coarse grain rings and improving the structure is achieved through smelting process control and two-stage homogenization treatment process. However, the two-stage homogenization treatment process adopted by the technology requires spray cooling to 300°C after heat preservation, and then cooling to room temperature by direct water flushing, which has strict requirements on equipment conditions and low general adaptability.

[0005] The prior art discloses a method for controlling the coarse grains on the end face of an aluminum alloy bar, wherein the mass percentage of the alloy components is: Zn 0.05-0.10%, Mg 0.5-0.7%, Cu 0.05-0.10%, Mn 0.4-0.5%, Cr 0.05-0.10%, Ti≤0.05%, B≤0.05%, Si 1.0-1.1%, Fe≤0.2%, a single impurity ≤0.05%, a total of ≤0.15%, and the remainder is Al, and the end face quenching coarse grain defects caused by sawing deformation of low-magnification samples are controlled by adding a sample removal deformation zone process during the extrusion process and controlling the sample online sawing deformation length. However, the homogenization heat treatment process, extrusion process and solution aging heat treatment process described in the technology are not suitable for the extruded bar of the present invention. Summary of the invention

[0006] The main purpose of the present invention is to provide an aluminum alloy bar and a multi-stage temperature control preparation method and application to solve the problems of coarse and uneven grains and low mechanical properties in the aluminum alloy bar in the prior art.

[0007] In order to achieve the above object, according to one aspect of the present invention, there is provided an aluminum alloy bar, comprising the following component elements in weight percentage:

[0008] Si 1.3%~1.5%, Fe 1.5%~1.6%, Cu 2.7%~2.9%, Mg 1.9%~2.1%, Ti≤0.1%, Ni 1.5%~1.7%, Mn 0.1%~0.2%, Cr≤0.1%, Zn 0.05%~0.15%; single impurity ≤0.05%, total impurities ≤0.1%, the balance is Al, totaling 100%.

[0009] Furthermore, the aluminum alloy rod includes the following component elements in weight percentage: Si 1.4% to 1.5%, Fe 1.55% to 1.6%, Cu 2.8% to 2.9%, Mg 2.0% to 2.1%, Ti≤0.1%, Ni 1.6% to 1.7%, Mn 0.1% to 0.2%, Cr≤0.1%, Zn 0.1% to 0.15%; single impurity ≤0.05%, total impurities ≤0.1%, the remainder is Al, totaling 100%.

[0010] Furthermore, the diameter of the aluminum alloy rod is 20 mm to 100 mm.

[0011] According to a second aspect of the present invention, there is provided a multi-stage temperature-controlled preparation method for the above-mentioned aluminum alloy bar, comprising the following steps:

[0012] Step 1: proportioning the aluminum alloy bar according to the proportion of each component element, and smelting to obtain an ingot;

[0013] Step 2: performing homogenization heat treatment on the ingot to obtain a homogenization heat treated ingot;

[0014] Step 3: performing the first stage temperature control treatment and the second stage temperature control treatment on the homogenized heat treated ingot in sequence; wherein,

[0015] The first stage temperature control treatment includes: heating the homogenization heat treatment ingot to 350°C to 380°C, and keeping the temperature for 20min to 40min to obtain the heat-insulated ingot;

[0016] The second stage temperature control treatment includes: roughening and maintaining the ingot at a temperature of 350°C to 380°C to obtain a roughened ingot; wherein the holding time and the extruded bar diameter satisfy the following relationship:

[0017] t = λ·D;

[0018] t is the holding time of the ingot after roughening, in minutes, and D is the diameter of the extruded bar, in millimeters;

[0019] When 20mm≤D≤50mm, 0.02≤λ≤0.4; when 50mm<D≤100mm, 0.01≤λ≤0.16;

[0020] Step 4: hot extruding the roughened ingot to obtain an extruded bar;

[0021] Step 5: performing double solution heat treatment on the extruded rod to obtain a solution heat treated rod; wherein the double solution heat treatment includes a first-stage solution heat treatment and a second-stage solution heat treatment, the first-stage solution heat treatment temperature is 400°C to 430°C, and the holding time is 0.5h to 1h;

[0022] Step 6: The solution heat treated rod is stretched, straightened and subjected to aging heat treatment to obtain an aluminum alloy rod.

[0023] Furthermore, the first stage temperature control treatment includes: heating the homogenization heat treatment ingot to 360°C to 380°C, and keeping the temperature for 20min to 40min to obtain the heat-insulated ingot.

[0024] Furthermore, the conditions for hot extrusion include: when the extrusion ratio is 10-15, the extrusion speed of the roughened ingot is 0.5-1.0 mm / s; when the extrusion ratio is 16-30, the extrusion speed of the roughened ingot is 1.5-2.5 mm / s.

[0025] Furthermore, the conditions for hot extrusion also include: the temperature of the extrusion barrel is 440°C to 460°C, and the heating temperature of the extrusion die is 440°C to 460°C.

[0026] Furthermore, the extrusion die for hot extrusion is a flat die, the inlet angle is 75° to 85°, and the working belt length is 5 to 9 mm.

[0027] Furthermore, the first stage solution heat treatment temperature is 410°C to 430°C, and the holding time is 0.5h to 1h.

[0028] Furthermore, the second stage solution heat treatment temperature is 500°C to 530°C, and the holding time is 1.5h to 3.5h.

[0029] Furthermore, the solution heat treated rod is water cooled to 15°C to 30°C.

[0030] Furthermore, the conditions of the aging heat treatment include: the aging heat treatment temperature is 185° C. to 195° C., and the insulation time is 8 h to 24 h.

[0031] According to a third aspect of the present invention, there is provided application of the above-mentioned aluminum alloy rod or the aluminum alloy rod obtained by the above-mentioned preparation method in aviation materials.

[0032] The technical scheme of the present invention is applied to provide an aluminum alloy bar and a multi-stage temperature control preparation method. By optimizing the ratio of the elements of each component of the aluminum alloy, the morphology of grain refinement and homogenization is improved, which is beneficial to improving the mechanical properties of the product; by matching the multi-stage temperature control operations such as ingot insulation and specific roughening process and hot extrusion, the extrusion deformation energy storage is adjusted, and then the solution heat treatment system is further regulated to make the alloy recover and release the deformation energy storage during low-temperature solution, reduce the recrystallization energy storage during high-temperature solution, and reduce the nucleation rate and growth rate of the crystal nucleus during the solution, so as to achieve fine grains and The purpose of uniformity is that elements such as Si, Mg, and Cu can form strengthening phases such as MgSi, AlCu, and AlCuMg during aging to improve the mechanical properties of the product. The present invention not only reduces the nucleation rate and growth rate of the crystal nucleus through the optimization of the extrusion process and the heat treatment system, so that the grain morphology meets the use requirements, but also improves the strength of the alloy, so that the tensile strength is ≥430MPa, the yield strength is ≥300MPa, and the elongation is ≥16.0%. The method for preparing uniform fine-grained extruded rods with multi-stage temperature control of the present invention is suitable for heat-resistant aluminum alloy extruded rods with a diameter of 20mm to 100mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0034] Figure 1 This is a photograph of the aluminum alloy extruded bar prepared in Example 1 of the present invention;

[0035] Figure 2 This is a metallographic microscope image of the aluminum alloy extruded rod prepared in Example 1 of the present invention;

[0036] Figure 3 This is a photograph of an aluminum alloy extruded bar prepared in Example 2 of the present invention;

[0037] Figure 4 This is a metallographic microscope image of the aluminum alloy extruded rod prepared in Example 2 of the present invention;

[0038] Figure 5 This is a photograph of an aluminum alloy extruded bar prepared in Comparative Example 1 of the present invention;

[0039] Figure 6 This is a metallographic microscope image of the aluminum alloy extruded bar prepared in Comparative Example 1 of the present invention;

[0040] Figure 7 A schematic diagram of the inlet angle of the die used for extruding the rod of the present invention;

[0041] Figure 8 Schematic diagram of the process for preparing the aluminum alloy extruded rods according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0043] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0044] Aiming at the problem that the aluminum alloy bar has coarse grains, and the tensile strength and the yield strength need to be further improved in the prior art, the present invention provides an aluminum alloy bar, which comprises the following component elements in weight percentage: Si 1.3%-1.5%, Fe 1.5%-1.6%, Cu 2.7%-2.9%, Mg 1.9%-2.1%, Ti≤0.1%, Ni 1.5%-1.7%, Mn 0.1%-0.2%, Cr≤0.1%, Zn 0.05%-0.15%; a single impurity is ≤0.05%, a total impurity is ≤0.1%, and the balance is Al, which is 100% in total.

[0045] In the aluminum alloy formula of the present invention, the proportion of Si element is selected from any value among 1.3%, 1.33%, 1.35%, 1.38%, 1.40%, 1.42%, 1.45%, 1.48%, 1.50% or any range between two values; the proportion of Fe element is selected from any value among 1.5%, 1.52%, 1.53%, 1.54%, 1.55%, 1.56%, 1.57%, 1.58%, 1.59%, 1.60% or any range between two values; the proportion of Cu element is selected from 2.7%, 2.72%, 2.75%, 2.78%, 2.80%, 2.82%, 2.85%, 2 .88%, 2.90% or any range between them; the Mg element is selected from 1.9%, 1.93%, 1.95%, 2.0%, 2.02%, 2.05%, 2.08%, 2.1% or any range between them; the proportion of the Ni element is selected from 1.5%, 1.53%, 1.55%, 1.58%, 1.60%, 1.62%, 1.65%, 1.68%, 1.70% or any range between them; the proportion of the Mn element is selected from 0.1%, 0.12%, 0.15%, 0.18%, 0.2% or any range between them.

[0046] The present invention optimizes the component formula of the aluminum alloy rod material so that the material can be suitable for a low-temperature extrusion process, and the optimized formula can make the grain structure of the aluminum alloy rod material finer and more evenly distributed, and is also beneficial to improving the mechanical properties of the rod material; for example, in the formula, the Mn element has the effect of inhibiting grain recrystallization, and elements such as Si, Mg, and Cu can form strengthening phases such as MgSi, AlCu, and AlCuMg during the aging process, and can also improve the mechanical properties of the product; the aluminum alloy rod material of the present invention has good grain morphology and high alloy strength, such as tensile strength ≥430MPa, yield strength ≥300MPa, and elongation ≥16.0%.

[0047] As a preferred embodiment, the aluminum alloy bar includes the following weight percentages of component elements: Si 1.4% to 1.5%, Fe 1.55% to 1.6%, Cu 2.8% to 2.9%, Mg 2.0% to 2.1%, Ti ≤ 0.1%, Ni 1.6% to 1.7%, Mn 0.1% to 0.2%, Cr ≤ 0.1%, Zn 0.1% to 0.15%; individual impurities ≤ 0.05%, total impurities ≤ 0.1%, the remainder is Al, a total of 100%. The present invention further optimizes the formula of the aluminum alloy bar, which can further improve the grain morphology to be small and evenly distributed, and improve the mechanical properties, such as tensile strength ≥ 435MPa, further ≥ 440MPa, yield strength ≥ 320MPa, further ≥ 330MPa.

[0048] As a preferred implementation manner, the diameter of the aluminum alloy rod is 20 mm to 100 mm.

[0049] According to a second aspect of the present invention, there is provided a multi-stage temperature-controlled preparation method for the above-mentioned aluminum alloy bar, comprising the following steps:

[0050] Step 1: proportioning the aluminum alloy bar according to the proportion of each component element, and smelting to obtain an ingot;

[0051] Step 2: performing homogenization heat treatment on the ingot to obtain a homogenization heat treated ingot;

[0052] Step 3: performing the first stage temperature control treatment and the second stage temperature control treatment on the homogenized heat treated ingot in sequence; wherein,

[0053] The first stage temperature control treatment includes: heating the homogenization heat treatment ingot to 350°C to 380°C, and keeping the temperature for 20min to 40min to obtain the heat-insulated ingot;

[0054] The second stage temperature control treatment includes: roughening and maintaining the ingot at a temperature of 350°C to 380°C to obtain a roughened ingot; wherein the holding time and the extruded bar diameter satisfy the following relationship:

[0055] t = λ·D;

[0056] t is the holding time of the ingot after roughening, in minutes, and D is the diameter of the extruded bar, in millimeters;

[0057] When 20mm≤D≤50mm, 0.02≤λ≤0.4; when 50mm<D≤100mm, 0.01≤λ≤0.16;

[0058] Step 4: hot extruding the roughened ingot to obtain an extruded bar;

[0059] Step 5: performing double solution heat treatment on the extruded rod to obtain a solution heat treated rod; wherein the double solution heat treatment includes a first-stage solution heat treatment and a second-stage solution heat treatment, the first-stage solution heat treatment temperature is 400°C to 430°C, and the holding time is 0.5h to 1h;

[0060] Step 6: The solution heat treated rod is stretched, straightened and subjected to aging heat treatment to obtain an aluminum alloy rod.

[0061] The heating temperature of the first stage temperature control of the present invention is selected from any value of 350°C, 355°C, 360°C, 365°C, 370°C, 375°C, 380°C or any range between two values; the first stage solution heat treatment temperature is selected from any value of 400°C, 405°C, 410°C, 415°C, 420°C, 425°C, 430°C or any range between two values;

[0062] When 20mm≤D≤50mm, the value of λ is selected from any value among 0.02, 0.05, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, or a range between any two of them; when 50mm<D≤100mm, the value of λ is selected from any value among 0.01, 0.03, 0.05, 0.08, 0.1, 0.12, 0.14, 0.15, 0.16, or a range between any two of them.

[0063] The invention can improve the grain morphology and enhance the mechanical properties of the aluminum alloy by performing a two-stage temperature control process, specific temperature control conditions, a double solid solution system and specific first-stage low-temperature solid solution conditions on the ingot; wherein the two-stage temperature control process is more conducive to the subsequent hot extrusion process, the first-stage low-temperature solid solution can make the alloy recover and release the deformation energy storage, reduce the recrystallization energy storage during the high-temperature solid solution process, reduce the nucleation rate and growth rate of the crystal nucleus during the solid solution process, and achieve the purpose of fine and uniform grains; the method of the invention is particularly suitable for heat-resistant aluminum alloy extrusion rods with a diameter of 20 mm to 100 mm.

[0064] As a specific implementation method, the first stage temperature control treatment includes: heating the homogenized heat treated ingot to 360°C to 380°C, and keeping it warm for 20min to 40min to obtain a heat-insulated ingot. The present invention adopts the low temperature heating temperature and the aluminum alloy component ratio to match. On the one hand, the temperature can meet the good hot formability of the ingot, and on the other hand, the low temperature can reduce the extrusion deformation energy storage, which is beneficial to the improvement of the grain morphology. The present invention adopts a suitable heat preservation time, which can not only save energy and reduce manufacturing costs, but also is beneficial to the hot formability of the ingot.

[0065] As a preferred embodiment, when 20mm≤D≤50mm, 0.02≤λ≤0.4; when 50mm<D≤100mm, 0.01≤λ≤0.16. The present invention further optimizes the relationship between the ingot insulation time and the extruded bar diameter, and can accurately perform an appropriate insulation process for extruded bars of different diameters, which is beneficial to the aluminum alloy grain morphology and the subsequent hot pressing process.

[0066] As a preferred embodiment, the first stage solid solution heat treatment temperature is 410°C to 430°C, and the holding time is 0.5h to 1h. By further optimizing the first stage solid solution heat treatment temperature and holding time, the present invention can make the alloy recover and release deformation energy storage, reduce recrystallization energy storage during high temperature solid solution, reduce the nucleation rate and growth rate of crystal nuclei during solid solution, and achieve the purpose of fine and uniform grains.

[0067] As a preferred embodiment, the hot extrusion conditions include: when the extrusion ratio is 10 to 15, the extrusion speed of the roughened ingot is 0.5 to 1.0 mm / s; when the extrusion ratio is 16 to 30, the extrusion speed of the roughened ingot is 1.5 to 2.5 mm / s. The present invention adopts matching extrusion ratio and extrusion speed, which is conducive to controlling deformation energy storage during extrusion and uniformity of extruded bar forming.

[0068] As a preferred embodiment, the hot extrusion conditions also include: the extrusion barrel temperature is 440°C to 460°C, and the extrusion die heating temperature is 440°C to 460°C. The extrusion barrel and die heating temperatures of the present invention are higher than the ingot hot extrusion temperature, the purpose of which is to make the surface temperature of the ingot higher than the core temperature through heat conduction of the extrusion barrel, thereby reducing the surface deformation energy storage, which is beneficial to the control of the aluminum alloy grain morphology.

[0069] As a preferred embodiment, the extrusion die for hot extrusion is a flat die, the inlet angle is 75° to 85°, and the working zone length is 5 to 9 mm. The inlet angle is, for example, 75°, 80°, and 85°. The present invention adopts the preferred die inlet angle and the matching working zone length, which is beneficial to the uniformity of grain distribution during the extrusion process of the aluminum alloy bar.

[0070] As a preferred embodiment, the conditions of the second stage solution heat treatment include: the solution heat treatment temperature is 500°C to 530°C, and the holding time is 1.5h to 3.5h. For example, the solution temperature is selected from any one of 500°C, 505°C, 510°C, 515°C, 520°C, 525°C, and 530°C, or a range between any two of them.

[0071] The present invention first adopts a relatively low-temperature first-stage solid solution heat treatment, which can cause the alloy to recover and release deformation energy, reduce the nucleation rate and growth rate of the second-stage high-temperature solid solution process, and achieve the purpose of fine and uniform grains. The second-stage solid solution heat treatment adopts the above-mentioned preferred temperature and holding time to ensure that the soluble second phase is fully dissolved back to form a supersaturated solid solution, which is beneficial to improving the performance of the rod.

[0072] As a specific implementation method, the solution heat treated rod is water cooled to 15°C to 30°C.

[0073] As a specific implementation, the conditions of aging heat treatment include: aging heat treatment temperature is 185°C to 195°C, and the holding time is 8h to 24h. For example, the aging heat treatment temperature is selected from 185°C, 190°C, and 195°C. The present invention adopts the aging heat treatment conditions to match the above-mentioned hot extrusion process and solution heat treatment process, which can fully precipitate the strengthening phase and improve the mechanical properties of the aluminum alloy bar.

[0074] The present invention optimizes the ratio of the elements of each component of the aluminum alloy, performs multi-stage temperature control operations such as heat preservation of the ingot and a specific roughening process, matches hot extrusion, extrusion speed, extrusion ratio, etc., and performs a double solution heat treatment system of first low-temperature solution and then high-temperature solution. The aluminum alloy bar prepared by the present invention has fine grains, uniform distribution, and better mechanical properties, such as tensile strength ≥430MPa, yield strength ≥300MPa, and elongation ≥16.0%. Therefore, the aluminum alloy bar prepared by the present invention can be used in aviation materials.

[0075] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0076] The embodiment of the present invention uses a universal tensile machine to detect the yield strength, tensile strength and elongation of the aluminum alloy bar product. The grain size evaluation refers to the standard GB / T 3246.2-2012 Macrostructure Inspection Method for Deformed Aluminum and Aluminum Alloy Products.

[0077] Example 1

[0078] An aluminum alloy extruded bar material, wherein the proportions of its components are as follows: by weight percentage, Si 1.3%, Fe 1.5%, Cu 2.7%, Mg 1.9%, Ti≤0.1%, Ni 1.5%, Mn 0.1%, Cr≤0.1%, Zn 0.05%, individual impurities≤0.05%, total≤0.1%, and the rest is Al.

[0079] The raw materials Al ingot, Mg ingot, Al-Si master alloy, Al-Fe master alloy, Al-Cu master alloy, Al-Ti master alloy, Al-Ni master alloy, Al-Mn master alloy, Al-Cr master alloy, Al-Zn master alloy, etc. are melted according to the element ratio and cast to obtain the required ingot.

[0080] The first stage temperature control treatment: the ingot subjected to homogenization heat treatment (homogenization temperature is 495°C, insulation time is 15h) is heated to 350°C, and insulation is carried out for 20min to obtain an insulation ingot; the second stage temperature control treatment: the insulation ingot is placed into the extrusion barrel within 2min, and after roughening, it is insulation for 1min, and then extruded. The extrusion die structure is a flat die, the die inlet angle is 75°, and the working belt length is 5mm; the extrusion process is: the extrusion barrel temperature is 460°C, the extrusion die temperature is 460°C, the extrusion speed is 0.5mm / s, and the extrusion ratio is 10 to obtain an extruded rod. The obtained extruded rods were subjected to solution heat treatment, and the solution system was as follows: the first stage solution temperature was 400°C, the holding time was 0.5h, the second stage solution temperature was 500°C, the holding time was 1.5h, and the solution heat treatment was followed by water cooling to room temperature; the rods after solution heat treatment were stretched and straightened, and the stretching straightening amount was ≤2.0%; the straightened extruded rods were subjected to artificial aging heat treatment, the artificial aging temperature was 185°C, the holding time was 8h, and the rods were air cooled to room temperature to obtain aluminum alloy extruded rods. The microstructure properties of the obtained extruded rods are shown in Table 1, and the low-magnification microstructure photos are shown in Table 1. Figure 1 As shown, the high-powered metallographic microscope image is as follows Figure 2 As shown, diameter 28mm.

[0081] Example 2

[0082] An aluminum alloy extruded bar material, wherein the proportions of its components are as follows: by weight percentage, Si 1.4%, Fe 1.55%, Cu 2.8%, Mg 2.0%, Ti≤0.1%, Ni 1.6%, Mn 0.15%, Cr≤0.1%, Zn 0.1%, individual impurities ≤0.05%, total ≤0.1%, and the rest is Al.

[0083] The raw materials Al ingot, Mg ingot, Al-Si master alloy, Al-Fe master alloy, Al-Cu master alloy, Al-Ti master alloy, Al-Ni master alloy, Al-Mn master alloy, Al-Cr master alloy, Al-Zn master alloy, etc. are melted according to the element ratio and cast to obtain the required ingot.

[0084] The first stage temperature control treatment: the ingot subjected to homogenization heat treatment (homogenization temperature is 495°C, insulation time is 15h) is heated to 365°C, and insulation is carried out for 30min to obtain an insulation ingot; the second stage temperature control treatment: the insulation ingot is placed into the extrusion barrel within 2min, and after roughening, it is insulation for 5min, and then extruded. The extrusion die structure is a flat die, the die inlet angle is 80°, and the working belt length is 7mm; the extrusion process is: the extrusion barrel temperature is 450°C, the extrusion die temperature is 450°C, the extrusion speed is 0.75mm / s, the extrusion ratio is 12.5, and the extruded rod is obtained with a diameter of 45mm.

[0085] The obtained extruded rods were subjected to solution heat treatment, and the solution system was as follows: the first stage solution temperature was 415°C, the holding time was 0.75h, the second stage solution temperature was 515°C, the holding time was 2.5h, and the solution heat treatment was followed by water cooling to room temperature; the rods after solution heat treatment were stretched and straightened, and the stretching straightening amount was ≤2.0%; the straightened extruded rods were subjected to artificial aging heat treatment, the artificial aging temperature was 190°C, the holding time was 16h, and the rods were air cooled to room temperature to obtain aluminum alloy extruded rods. The microstructure properties of the obtained extruded rods are shown in Table 1, and the low-magnification microstructure photos are shown in Table 1. Figure 3 As shown, the high-magnification microstructure metallographic image is as follows Figure 4 shown.

[0086] Example 3

[0087] An aluminum alloy extruded bar material, wherein the proportions of its components are as follows: by weight percentage, Si 1.5%, Fe 1.6%, Cu 2.9%, Mg 2.1%, Ti≤0.1%, Ni 1.7%, Mn 0.2%, Cr≤0.1%, Zn 0.15%, a single impurity ≤0.05%, a total of ≤0.1%, and the rest is Al.

[0088] The raw materials Al ingot, Mg ingot, Al-Si master alloy, Al-Fe master alloy, Al-Cu master alloy, Al-Ti master alloy, Al-Ni master alloy, Al-Mn master alloy, Al-Cr master alloy, Al-Zn master alloy, etc. are melted according to the element ratio and cast to obtain the required ingot.

[0089] The first stage temperature control treatment: the ingot subjected to homogenization heat treatment (homogenization temperature is 495°C, insulation time is 15h) is heated to 380°C, and insulation is performed for 40min to obtain an insulation ingot; the second stage temperature control treatment: the insulation ingot is placed into the extrusion barrel within 2min, and after roughening, it is insulation for 8min, and then extruded. The extrusion die structure is a flat die, the die inlet angle is 85°, and the working belt length is 9mm; the extrusion process is: the extrusion barrel temperature is 440°C, the extrusion die temperature is 440°C, the extrusion speed is 1.0mm / s, the extrusion ratio is 15, and the extruded rod is obtained with a diameter of 60mm.

[0090] The obtained extruded rods were subjected to solution heat treatment, and the solution system was as follows: the first-stage solution temperature was 430°C, the holding time was 1h, the second-stage solution temperature was 530°C, the holding time was 3.5h, and the solution heat treatment was followed by water cooling to room temperature; the rods after solution heat treatment were stretched and straightened, and the stretching straightening amount was ≤2.0%; the straightened extruded rods were subjected to artificial aging heat treatment, the artificial aging temperature was 195°C, the holding time was 24h, and the rods were air cooled to room temperature to obtain aluminum alloy extruded rods. The microstructure and properties of the obtained extruded rods are shown in Table 1.

[0091] Example 4

[0092] An aluminum alloy extruded bar material, wherein the proportions of its components are as follows: by weight percentage, Si 1.3%, Fe 1.5%, Cu 2.7%, Mg 1.9%, Ti≤0.1%, Ni 1.5%, Mn 0.1%, Cr≤0.1%, Zn 0.05%, individual impurities≤0.05%, total≤0.1%, and the rest is Al.

[0093] The raw materials Al ingot, Mg ingot, Al-Si master alloy, Al-Fe master alloy, Al-Cu master alloy, Al-Ti master alloy, Al-Ni master alloy, Al-Mn master alloy, Al-Cr master alloy, Al-Zn master alloy, etc. are melted according to the element ratio and cast to obtain the required ingot.

[0094] The first stage temperature control treatment: the ingot subjected to homogenization heat treatment (homogenization temperature is 495°C, insulation time is 15h) is heated to 380°C, and insulation is performed for 40min to obtain an insulation ingot; the second stage temperature control treatment: the insulation ingot is placed into the extrusion barrel within 2min, and after roughening, it is insulation for 8min, and then extruded. The extrusion die structure is a flat die, the die inlet angle is 75°, and the working belt length is 5mm; the extrusion process is: the extrusion barrel temperature is 440°C, the extrusion die temperature is 440°C, the extrusion speed is 1.5mm / s, the extrusion ratio is 16, and the extruded rod is obtained with a diameter of 80mm.

[0095] The obtained extruded rods were subjected to solution heat treatment, and the solution system was as follows: the first-stage solution temperature was 400°C, the holding time was 0.5h, the second-stage solution temperature was 500°C, the holding time was 1.5h, and the solution heat treatment was followed by water cooling to room temperature; the rods after solution heat treatment were stretched and straightened, and the stretching straightening amount was ≤2.0%; the straightened extruded rods were subjected to artificial aging heat treatment, the artificial aging temperature was 185°C, the holding time was 8h, and the rods were air cooled to room temperature to obtain aluminum alloy extruded rods. The microstructure and properties of the obtained extruded rods are shown in Table 1.

[0096] Example 5

[0097] An aluminum alloy extruded bar material, wherein the proportions of its components are as follows: by weight percentage, Si 1.4%, Fe 1.55%, Cu 2.8%, Mg 2.0%, Ti≤0.1%, Ni 1.6%, Mn 0.15%, Cr≤0.1%, Zn 0.1%, individual impurities ≤0.05%, total ≤0.1%, and the rest is Al.

[0098] The raw materials Al ingot, Mg ingot, Al-Si master alloy, Al-Fe master alloy, Al-Cu master alloy, Al-Ti master alloy, Al-Ni master alloy, Al-Mn master alloy, Al-Cr master alloy, Al-Zn master alloy, etc. are melted according to the element ratio and cast to obtain the required ingot.

[0099] The first stage temperature control treatment: the ingot subjected to homogenization heat treatment (homogenization temperature is 495°C, insulation time is 15h) is heated to 370°C, and insulation is carried out for 30min to obtain an insulation ingot; the second stage temperature control treatment: the insulation ingot is placed into the extrusion barrel within 2min, and after roughening, it is insulation for 1min, and then extruded. The extrusion die structure is a flat die, the die inlet angle is 80°, and the working belt length is 7mm; the extrusion process is: the extrusion barrel temperature is 450°C, the extrusion die temperature is 450°C, the extrusion speed is 2.0mm / s, the extrusion ratio is 23, and the extruded rod is obtained with a diameter of 100mm.

[0100] The obtained extruded rods were subjected to solution heat treatment, and the solution system was as follows: the first-stage solution temperature was 415°C, the holding time was 0.75h, the second-stage solution temperature was 515°C, the holding time was 2.5h, and the solution heat treatment was followed by water cooling to room temperature; the rods after solution heat treatment were stretched and straightened, and the stretching straightening amount was ≤2.0%; the straightened extruded rods were subjected to artificial aging heat treatment, the artificial aging temperature was 190°C, the holding time was 16h, and the rods were air cooled to room temperature to obtain aluminum alloy extruded rods. The microstructure and properties of the obtained extruded rods are shown in Table 1.

[0101] Example 6

[0102] An aluminum alloy extruded bar material, wherein the proportions of its components are as follows: by weight percentage, Si 1.5%, Fe 1.6%, Cu 2.9%, Mg 2.1%, Ti≤0.1%, Ni 1.7%, Mn 0.2%, Cr≤0.1%, Zn 0.15%, a single impurity ≤0.05%, a total of ≤0.1%, and the rest is Al.

[0103] The raw materials Al ingot, Mg ingot, Al-Si master alloy, Al-Fe master alloy, Al-Cu master alloy, Al-Ti master alloy, Al-Ni master alloy, Al-Mn master alloy, Al-Cr master alloy, Al-Zn master alloy, etc. are melted according to the element ratio and cast to obtain the required ingot.

[0104] The first stage temperature control treatment: the ingot subjected to homogenization heat treatment (homogenization temperature is 495°C, insulation time is 15h) is heated to 350°C, and insulation is carried out for 20min to obtain an insulation ingot; the second stage temperature control treatment: the insulation ingot is placed into the extrusion barrel within 2min, and after roughening, it is kept warm for 2min, and then extruded. The extrusion die structure is a flat die, the die inlet angle is 85°, and the working belt length is 9mm; the extrusion process is as follows: the roughening ingot temperature is 350°C, the extrusion barrel temperature is 460°C, the extrusion die temperature is 460°C, the extrusion speed is 2.5mm / s, the extrusion ratio is 30, and the extruded rod is obtained with a diameter of 45mm.

[0105] The obtained extruded rods were subjected to solution heat treatment, and the solution system was as follows: the first-stage solution temperature was 430°C, the holding time was 1h, the second-stage solution temperature was 530°C, the holding time was 3.5h, and the solution heat treatment was followed by water cooling to room temperature; the rods after solution heat treatment were stretched and straightened, and the stretching straightening amount was ≤2.0%; the straightened extruded rods were subjected to artificial aging heat treatment, the artificial aging temperature was 195°C, the holding time was 24h, and the rods were air cooled to room temperature to obtain aluminum alloy extruded rods. The microstructure and properties of the obtained extruded rods are shown in Table 1.

[0106] Example 7

[0107] The difference between Example 7 and Example 3 is that the die inlet angle is 65°, the working belt length is 4 mm; the extrusion barrel temperature is 420°C, the extrusion die temperature is 420°C; the extrusion speed is 1.0 mm / s, and the extrusion ratio is 18; the alloy rod diameter is 60 mm, and the performance test is shown in Table 1.

[0108] Example 8

[0109] The difference between Example 8 and Example 3 is that the second solution heat treatment temperature is 550° C. and the insulation time is 4 hours; the alloy rod has a diameter of 28 mm, and the performance test is shown in Table 1.

[0110] Example 9

[0111] The difference between Example 9 and Example 3 is that the artificial aging heat treatment temperature is 175° C. and the insulation time is 28 hours; the alloy rod has a diameter of 45 mm, and the performance test is shown in Table 1.

[0112] Comparative Example 1

[0113] An aluminum alloy extruded bar material, wherein the proportions of the components are as follows: by weight percentage, Si 1.2%, Fe 1.3%, Cu 2.2%, Mg 1.3%, Ti≤0.1%, Ni 1.2%, Cr≤0.1%, a single impurity≤0.05%, a total of≤0.1%, and the rest is Al.

[0114] The raw materials Al ingot, Mg ingot, Al-Si master alloy, Al-Fe master alloy, Al-Cu master alloy, Al-Ti master alloy, Al-Ni master alloy, Al-Cr master alloy, etc. are melted according to the element ratio and cast to obtain the required ingot.

[0115] The first stage temperature control treatment: the ingot after homogenization heat treatment (homogenization temperature is 495℃, insulation time is 15h) is heated to 365℃, and kept warm for 20min to obtain the ingot; the second stage temperature control treatment: the ingot is placed in the extrusion barrel within 2min, and kept warm for 2min after roughening, and then extruded. The extrusion die structure is a flat die, the die inlet angle is 80°, and the working belt length is 7mm; the extrusion process is: the extrusion barrel temperature is 460℃, the extrusion die temperature is 460, the extrusion speed is 0.75mm / s, the extrusion ratio is 12.5, and the extruded rod is obtained with a diameter of 45mm.

[0116] The obtained extruded rods were subjected to solution heat treatment, and the solution system was as follows: the first stage solution temperature was 415°C, the holding time was 0.75h, the second stage solution temperature was 515°C, the holding time was 2.5h, and the solution heat treatment was followed by water cooling to room temperature; the rods after solution heat treatment were stretched and straightened, and the stretching straightening amount was ≤2.0%; the straightened extruded rods were subjected to artificial aging heat treatment, the artificial aging temperature was 190°C, the holding time was 16h, and the rods were air cooled to room temperature to obtain aluminum alloy extruded rods. The microstructure properties of the obtained extruded rods are shown in Table 1, and the low-magnification microstructure photos are shown in Table 1. Figure 5 As shown, the high-magnification microstructure metallographic image is as follows Figure 6 shown.

[0117] Comparative Example 2

[0118] An aluminum alloy extruded bar material, wherein the proportions of its components are as follows: by weight percentage, Si 1.3%, Fe 1.5%, Cu 2.7%, Mg 1.9%, Ti≤0.1%, Ni 1.5%, Mn 0.1%, Cr≤0.1%, Zn 0.05%, individual impurities≤0.05%, total≤0.1%, and the rest is Al.

[0119] The raw materials Al ingot, Mg ingot, Al-Si master alloy, Al-Fe master alloy, Al-Cu master alloy, Al-Ti master alloy, Al-Ni master alloy, Al-Mn master alloy, Al-Cr master alloy, Al-Zn master alloy, etc. are melted according to the element ratio and cast to obtain the required ingot.

[0120] The first stage temperature control treatment: the ingot subjected to homogenization heat treatment (homogenization temperature is 495°C, insulation time is 15h) is heated to 320°C, and insulation is performed for 40min to obtain an insulation ingot; the second stage temperature control treatment: the insulation ingot at about 320°C is placed into the extrusion barrel within 2min, and after roughening, it is insulation for 8min, and then extruded. The extrusion die structure is a flat die, the die inlet angle is 50°, and the working belt length is 2mm; the extrusion process is: the extrusion barrel temperature is 330°C, the extrusion die temperature is 330°C, the extrusion speed is 0.5mm / s, the extrusion ratio is 25, and the extruded rod is obtained with a diameter of 60mm.

[0121] The obtained extruded rods were subjected to solution heat treatment, and the solution system was as follows: solution temperature was 480°C, holding time was 1.5h, and water cooling was performed to room temperature after the solution heat treatment; the rods after solution heat treatment were stretched and straightened, and the stretching straightening amount was ≤2.0%; the straightened extruded rods were subjected to artificial aging heat treatment, the artificial aging temperature was 180°C, the holding time was 30h, and air cooling was performed to room temperature to obtain aluminum alloy extruded rods. The microstructure and properties of the obtained extruded rods are shown in Table 1.

[0122] Comparative Example 3

[0123] An aluminum alloy extruded bar material, wherein the proportions of its components are as follows: by weight percentage, Si 1.5%, Fe 1.6%, Cu 2.9%, Mg 2.1%, Ti≤0.1%, Ni 1.7%, Mn 0.2%, Cr≤0.1%, Zn 0.15%, a single impurity ≤0.05%, a total of ≤0.1%, and the rest is Al.

[0124] The raw materials Al ingot, Mg ingot, Al-Si master alloy, Al-Fe master alloy, Al-Cu master alloy, Al-Ti master alloy, Al-Ni master alloy, Al-Mn master alloy, Al-Cr master alloy, Al-Zn master alloy, etc. are melted according to the element ratio and cast to obtain the required ingot.

[0125] The ingot that had undergone homogenization heat treatment (homogenization temperature was 495°C, holding time was 15h) was extruded. The extrusion die structure was a flat die, the die inlet angle was 90°, and the working belt length was 8mm. The extrusion process was as follows: the ingot heating temperature was 400°C, the holding time was 10min, the extrusion barrel temperature was 470°C, the extrusion die temperature was 470°C, the extrusion speed was 2.0mm / s, the extrusion ratio was 10, and extruded rods were obtained.

[0126] The obtained extruded rods were subjected to solution heat treatment, and the solution system was as follows: the first-stage solution temperature was 440°C, the holding time was 2h, the second-stage solution temperature was 540°C, the holding time was 5h, and the solution heat treatment was followed by water cooling to room temperature; the rods after solution heat treatment were stretched and straightened, and the stretching straightening amount was ≤2.0%; the straightened extruded rods were subjected to artificial aging heat treatment, the artificial aging temperature was 200°C, the holding time was 4h, and the rods were air-cooled to room temperature to obtain aluminum alloy extruded rods. The microstructure and properties of the obtained extruded rods are shown in Table 1.

[0127] Comparative Example 4

[0128] The difference between Comparative Example 4 and Example 3 is that the ingot after homogenization heat treatment is heated to 380° C., without insulation and roughening, and directly subjected to hot extrusion process; the performance test of aluminum alloy bars is shown in Table 1.

[0129] Comparative Example 5

[0130] The difference between Comparative Example 5 and Example 3 is that the heating temperature of the ingot for homogenization heat treatment is 400° C. and the temperature is kept for 10 min. The performance test of the aluminum alloy bar is shown in Table 1.

[0131] Comparative Example 6

[0132] The difference between Comparative Example 6 and Example 3 is that the heating temperature of the ingot for homogenization heat treatment is 300° C. and the temperature is kept for 10 min. The performance test of the aluminum alloy bar is shown in Table 1.

[0133] Comparative Example 7

[0134] The difference between Comparative Example 7 and Example 3 is that the second-stage temperature control treatment is different, and the roughening holding time is 15 minutes; the aluminum alloy bar has a diameter of 28 mm, and the performance test is shown in Table 1.

[0135] Comparative Example 8

[0136] The difference between Comparative Example 8 and Example 3 is that the second-stage temperature control treatment is different, and the roughening holding time is 15s; the aluminum alloy bar has a diameter of 40mm, and the performance test is shown in Table 1.

[0137] Comparative Example 9

[0138] The difference between Comparative Example 9 and Example 3 is that the solid solution heat treatment process is one time: the solid solution temperature is 530° C., and the holding time is 3.5 h; the properties of the aluminum alloy rod are shown in Table 1.

[0139] Comparative Example 10

[0140] The difference between Comparative Example 10 and Example 3 is that the first-stage solid solution temperature is 380°C; the properties of the aluminum alloy rod are shown in Table 1.

[0141] Comparative Example 11

[0142] The difference between Comparative Example 11 and Example 3 is that the first-stage solid solution temperature is 450°C; the properties of the aluminum alloy rod are shown in Table 1.

[0143] Table 1 Microstructure and properties of extruded rods obtained in Examples 1 to 9 and Comparative Examples 1 to 11

[0144]

[0145]

[0146] The grains of the aluminum alloy bars prepared in Examples 1 to 9 of the present invention are fine and evenly distributed. Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown; tensile strength ≥ 430MPa, yield strength ≥ 310MPa, elongation ≥ 16.0%; by further optimizing the component ratio and process conditions, such as Figure 7 and Figure 8 , tensile strength ≥435MPa, yield strength ≥315MPa, elongation ≥17.0%; by further optimizing the component formula and process conditions, the tensile strength ≥440MPa, yield strength ≥320MPa, elongation ≥18.0%; even the tensile strength is 445MPa, the yield strength reaches 365MPa, and the elongation reaches 19.5%; the mechanical properties are very excellent.

[0147] The aluminum alloy component ratio of comparative example 1 is different from that of the present invention, with Si 1.2%, Cu 2.2%, and Mg 1.3% being relatively low. The prepared aluminum alloy bar has coarse grains and uneven distribution, and a tensile strength of 365 MPa, which is much lower than that of embodiments 1 to 9; the yield strength is similar. The present invention can improve the mechanical properties and grain morphology of the aluminum alloy bar by optimizing the formula of each component of the aluminum alloy bar and designing a reasonable element ratio.

[0148] The heating temperature of the ingot in comparative example 2 is too low, and the solid solution system is unreasonable. Although the mechanical properties of the prepared aluminum alloy bar are similar to those of embodiments 1 to 9 of the present invention, the grain morphology is poor, the particle size is large, and the distribution is uneven. The present invention optimizes the ingot heating temperature to 350 to 380°C on the basis of optimizing the aluminum alloy formula, and then optimizes the insulation, roughening, hot extrusion and double solid solution heat treatment system, which can significantly improve the grain morphology of the aluminum alloy bar and is also conducive to improving the mechanical properties.

[0149] In comparative example 3, the ingot is heated to 400°C and directly hot extruded without adopting a multi-stage temperature control process. The hot extrusion temperature is too high to easily promote grain growth and produce large grains, so the grain size of the obtained aluminum alloy bar is coarse. On the basis of optimizing the aluminum alloy formula, the present invention heats the ingot to 350-380°C, maintains the temperature, roughens the ingot, and hot extrude it, which can make the aluminum alloy bar fine in grain size, small in size, and evenly distributed, and is also conducive to improving mechanical properties.

[0150] Although the heating and extrusion temperature of the ingot in Comparative Example 4 is similar to that of the present invention, the specific ingot heating and insulation process and the roughening and insulation process are not carried out. The lack of these two steps is not conducive to the subsequent hot extrusion process and the grain morphology and mechanical properties. The present invention adopts the above two temperature control processes to make the grains of the aluminum alloy rod finer and more evenly distributed, which is beneficial to improving the mechanical properties.

[0151] The heating temperature of the ingots in Comparative Examples 5 and 6 is too high or too low, which is not conducive to the morphology and mechanical properties of the aluminum alloy grains. When the ingots in Comparative Examples 7 and 8 are subjected to the second temperature control process, the rod diameter and the holding time do not match, and the morphology of the prepared aluminum alloy grains is also relatively poor. The extruded rods in Comparative Example 9 adopt a single solution heat treatment process, and the temperature is too high, which has a poor effect on the morphology of the aluminum alloy grains. The extruded rods in Comparative Examples 10 and 11 have too high or too low temperatures during the first stage solution heat treatment, which is not conducive to the formation of fine and uniform morphology of the grains, and also affects their mechanical properties.

[0152] The above description shows that the embodiment of the present invention, based on the optimized aluminum alloy element formula, adopts a two-stage specific temperature control process and a double solution heat treatment as well as a specific first-stage solution heat treatment system, and multiple factors achieve the best synergistic effect, which can significantly improve the aluminum alloy grain morphology to be fine and uniformly distributed, and can make its tensile strength ≥430MPa, yield strength ≥300MPa, and elongation ≥16.0%.

[0153] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0154] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An aluminum alloy bar, characterized in that: The aluminum alloy bar comprises the following component elements in weight percentage: Si 1.3%~1.5%, Fe 1.5%~1.6%, Cu 2.7%~2.9%, Mg 1.9%~2.1%, Ti≤0.1%, Ni1.5%~1.7%, Mn 0.1%~0.2%, Cr≤0.1%, Zn 0.05%~0.15%; single impurity ≤0.05%, total impurities ≤0.1%, the balance is Al, totaling 100%.

2. The aluminum alloy bar according to claim 1, characterized in that: The aluminum alloy bar comprises the following component elements in weight percentage: Si 1.4%~1.5%, Fe 1.55%~1.6%, Cu 2.8%~2.9%, Mg 2.0%~2.1%, Ti≤0.1%, Ni1.6%~1.7%, Mn 0.1%~0.2%, Cr≤0.1%, Zn 0.1%~0.15%; single impurity ≤0.05%, total impurity ≤0.1%, the balance is Al, a total of 100%; And / or, the diameter of the aluminum alloy rod is 20 mm to 100 mm.

3. The multi-stage temperature control preparation method of the aluminum alloy bar according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: Step 1: proportioning the aluminum alloy bar according to the proportion of each component element, and smelting to obtain an ingot; Step 2: performing homogenization heat treatment on the ingot to obtain a homogenization heat treated ingot; Step 3: performing a first-stage temperature control treatment and a second-stage temperature control treatment on the homogenized heat treated ingot in sequence; wherein the first-stage temperature control treatment comprises: heating the homogenized heat treated ingot to 350° C. to 380° C., and keeping the temperature for 20 min to 40 min to obtain a heat-insulated ingot; The second stage temperature control treatment comprises: roughening and maintaining the heat-insulated ingot at a temperature of 350° C. to 380° C. in an extrusion barrel to obtain a roughened ingot; wherein the maintaining time and the extruded rod diameter satisfy the following relationship: t = λ·D; t is the holding time of the ingot after roughening, in minutes, and D is the diameter of the extruded bar, in millimeters; When 20mm≤D≤50mm, 0.02≤λ≤0.4; when 50mm<D≤100mm, 0.01≤λ≤0.16; Step 4: hot extruding the upset ingot to obtain the extruded rod; Step 5: performing double solution heat treatment on the extruded rod to obtain a solution heat treated rod; wherein the double solution heat treatment includes a first-stage solution heat treatment and a second-stage solution heat treatment, the first-stage solution heat treatment temperature is 400° C. to 430° C., and the holding time is 0.5 h to 1 h; Step 6: Perform stretching, straightening and aging heat treatment on the solution heat treated rod to obtain the aluminum alloy rod.

4. The multi-stage temperature control preparation method of the aluminum alloy bar according to claim 3, characterized in that: The first stage temperature control treatment comprises: heating the homogenization heat treatment ingot to 360° C. to 380° C., keeping the temperature for 20 min to 40 min, and obtaining a heat-insulated ingot; And / or, the first stage solution heat treatment temperature is 410° C. to 430° C., and the holding time is 0.5 h to 1 h.

5. The multi-stage temperature control preparation method of the aluminum alloy bar according to claim 3 or 4, characterized in that: The conditions of the hot extrusion include: when the extrusion ratio is 10-15, the extrusion speed of the rough ingot is 0.5-1.0 mm / s; when the extrusion ratio is 16-30, the extrusion speed of the rough ingot is 1.5-2.5 mm / s.

6. The multi-stage temperature control preparation method for an aluminum alloy bar according to any one of claims 3 to 5, characterized in that: The conditions for hot extrusion also include: the temperature of the extrusion barrel is 440°C to 460°C, and the heating temperature of the extrusion die is 440°C to 460°C.

7. The multi-stage temperature control preparation method for an aluminum alloy bar according to any one of claims 3 to 6, characterized in that: The hot extrusion die is a flat die, the inlet angle is 75° to 85°, and the working belt length is 5 to 9 mm.

8. The multi-stage temperature control preparation method for an aluminum alloy bar according to any one of claims 3 to 7, characterized in that: The conditions of the second stage solution heat treatment include: the solution heat treatment temperature is 500°C to 530°C, and the holding time is 1.5h to 3.5h; And / or, the solution heat treated rod is water cooled to 15°C to 30°C.

9. The multi-stage temperature control preparation method for an aluminum alloy bar according to any one of claims 3 to 8, characterized in that: The conditions of the aging heat treatment include: the aging heat treatment temperature is 185° C. to 195° C., and the insulation time is 8 h to 24 h.

10. Use of the aluminum alloy bar according to claim 1 or 2 or the aluminum alloy bar obtained by the preparation method according to any one of claims 3 to 9 in aviation materials.

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