Al-cu-mg-fe-ni aluminum alloy rod, method for producing the same, and use thereof

Abstract

The application discloses an Al-Cu-Mg-Fe-Ni aluminum alloy rod and a preparation method and application thereof. The aluminum alloy rod comprises the following components in percentage by weight: Si is less than or equal to 0.02, Fe is 0.7% to 0.9%, Cu is 1.8% to 2.1%, Mg is 1.3% to 1.4%, Ti is 0.02% to 0.08%, Ni is 0.7% to 0.9%, 0.1% is less than or equal to Mn+Cr+Zr which is less than or equal to 0.2%, single impurity is less than or equal to 0.05%, total impurity is less than or equal to 0.1%, the balance is Al, and the total is 100%. When the aluminum alloy rod is extruded, the head heating temperature of the aluminum alloy ingot is greater than the tail; the extrusion speed of the front section of the ingot is greater than the extrusion speed of the rear section. The metal grains of the aluminum alloy rod are small and uniform, meet the grain use requirement, the tensile strength of the rod is greater than or equal to 355 MPa, and the elongation is greater than or equal to 8.0%.

Description

Technical Field

[0001] This invention relates to the field of metallic materials technology, and more specifically, to an Al-Cu-Mg-Fe-Ni aluminum alloy rod, its preparation method, and its application. Background Technology

[0002] Al-Cu-Mg-Fe-Ni aluminum alloy is a heat-treatable aluminum alloy. The Al9FeNi, Al7Cu4Ni, and Al2CuMg phases present in the alloy give it good heat resistance and mechanical properties, making it widely used in defense, military, and aerospace fields. It has good cold and hot working properties and moderate weldability, making it suitable for manufacturing parts used at high temperatures. It is often used in aircraft engine pistons and shipbuilding materials. The extrusion technology of Al-Cu-Mg-Fe-Ni aluminum alloy requires high precision, especially in terms of strict requirements on grain size and uniformity.

[0003] Currently, domestically produced Al-Cu-Mg-Fe-Ni aluminum alloy rods generally suffer from uneven and coarse grains, resulting in a very low yield. This not only increases production costs but also seriously affects the demand for this material in the aerospace industry and the profitability of enterprises. Summary of the Invention

[0004] The main objective of this invention is to provide an Al-Cu-Mg-Fe-Ni aluminum alloy rod, its preparation method, and its application, in order to solve the problems of coarse and uneven grains and the need to improve mechanical properties in existing aluminum alloy rods.

[0005] To achieve the above objectives, according to one aspect of the present invention, an Al-Cu-Mg-Fe-Ni aluminum alloy rod is provided, comprising the following components in weight percentages:

[0006] Si ≤ 0.02%, Fe 0.7%–0.9%, Cu 1.8%–2.1%, Mg 1.3%–1.4%, Ti 0.02%–0.08%, Ni 0.7%–0.9%, 0.1% ≤ Mn + Cr + Zr ≤ 0.2%; individual impurities ≤ 0.05%, total impurities ≤ 0.1%, balance Al, totaling 100%.

[0007] Furthermore, the diameter of the aluminum alloy rod is 20–80 mm.

[0008] According to a second aspect of the present invention, a method for preparing Al-Cu-Mg-Fe-Ni aluminum alloy rods is provided, comprising hot extruding an Al-Cu-Mg-Fe-Ni aluminum alloy ingot to obtain extruded rods:

[0009] During the hot extrusion process, the heating temperature at the head of the aluminum alloy ingot is higher than that at the tail.

[0010] The extrusion speed at the front end of the aluminum alloy ingot is greater than the extrusion speed at the rear end.

[0011] Al-Cu-Mg-Fe-Ni aluminum alloy ingots are ingots prepared by using the proportions of each component of the above-mentioned Al-Cu-Mg-Fe-Ni aluminum alloy rods, or ingots prepared by using the proportions of each component of aluminum alloy rods of grade 2A70 or grade 2D70.

[0012] Furthermore, the Al-Cu-Mg-Fe-Ni aluminum alloy ingot is a heat-treated ingot, specifically including:

[0013] The aluminum alloy rods are prepared according to the proportion of each component, and then melted to obtain aluminum alloy ingots. The aluminum alloy ingots are then subjected to homogenization heat treatment to obtain heat-treated ingots.

[0014] Furthermore, the preparation method of Al-Cu-Mg-Fe-Ni aluminum alloy rods includes the following steps after the hot extrusion process:

[0015] The extruded bar is subjected to solution heat treatment to obtain a solution heat-treated bar; the solution heat-treated bar is subjected to stretch straightening to obtain a stretch straightened bar; the stretch straightened bar is subjected to aging heat treatment to obtain an Al-Cu-Mg-Fe-Ni aluminum alloy bar.

[0016] Furthermore, during the hot extrusion process, the heating temperature of the head of the aluminum alloy ingot is 5 to 20°C higher than that of the tail of the aluminum alloy ingot.

[0017] Furthermore, the head of the aluminum alloy ingot is heated to 430℃~440℃, and the tail of the aluminum alloy ingot is heated to 420℃~430℃.

[0018] Furthermore, the heating temperature of the hot extrusion die is 400℃~420℃, and the heating temperature of the extrusion cylinder inside the die is 400℃~420℃.

[0019] Furthermore, during the hot extrusion process, the half-length of the aluminum alloy ingot near the head is the front section, and the half-length of the aluminum alloy ingot near the tail is the rear section.

[0020] Furthermore, the extrusion speed of the front section is 1.5 to 2.0 mm / s, and the extrusion speed of the rear section is 0.5 to 1.0 mm / s.

[0021] Furthermore, the solution heat treatment includes a first solution heat treatment and a second solution heat treatment;

[0022] The first solution heat treatment process includes: a heating rate of 90℃ / h to 160℃ / h, a temperature of 440℃ to 460℃, and a holding time of 0.5h to 1.0h;

[0023] The second solution heat treatment process includes: a heating rate of 500℃ / h to 1000℃ / h, a temperature of 530℃ to 540℃, and a holding time of 1.5h to 2.5h.

[0024] Furthermore, the hot extrusion die is a flat die; the working zone length of the die is 2-3 mm.

[0025] Furthermore, during the stretching and straightening process, the stretching and straightening amount is ≤2.0%.

[0026] Furthermore, the aging heat treatment temperature is 195℃~205℃, and the holding time for the aging heat treatment is 8h~12h.

[0027] According to a third aspect of the present invention, the application of the above-described Al-Cu-Mg-Fe-Ni aluminum alloy rod or the Al-Cu-Mg-Fe-Ni aluminum alloy rod obtained by the above preparation method in aerospace materials is provided.

[0028] The present invention provides an Al-Cu-Mg-Fe-Ni aluminum alloy rod and its preparation method. By adding trace elements Mn, Cr, and Zr to the alloy feedstock, recrystallization growth can be suppressed, the crystallization ratio can be effectively adjusted, and the grains can be made uniform. By optimizing the extrusion process, such as setting the head extrusion temperature higher than the tail extrusion temperature, and the front extrusion speed higher than the middle extrusion speed higher than the rear extrusion speed, and by controlling the deformation energy storage during the extrusion process, both the nucleation rate and growth rate of crystal nuclei are reduced, resulting in fine and uniform grains that meet the grain requirements. Through a two-stage solid solution treatment, the tensile strength is ≥355MPa and the elongation is ≥8%. The Al-Cu-Mg-Fe-Ni aluminum alloy extrusion process of the present invention is not only applicable to 2A70 and 2D70 alloys, but can also be extended to other Al-Cu-Mg-Fe-Ni heat-resistant aluminum alloys. Attached Figure Description

[0029] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 The image shows a low-magnification microstructure of the aluminum alloy extruded bar prepared in Example 1 of the present invention;

[0031] Figure 2 The image shows a low-magnification microstructure of the aluminum alloy extruded bar prepared in Example 2 of the present invention;

[0032] Figure 3 The image shows a low-magnification microstructure of the aluminum alloy extruded bar prepared in Comparative Example 1 of this invention;

[0033] Figure 4 This shows a high-magnification microscopic image of the aluminum alloy extruded bar prepared in Example 1 of the present invention;

[0034] Figure 5 This shows a high-magnification microscopic image of the aluminum alloy extruded bar prepared in Example 2 of the present invention;

[0035] Figure 6 A high-magnification microscopic image of the aluminum alloy extruded bar prepared in Comparative Example 1 of the present invention is shown. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] This invention provides an Al-Cu-Mg-Fe-Ni aluminum alloy rod, comprising the following components by weight percentage:

[0038] Si ≤ 0.02%, Fe 0.7%–0.9%, Cu 1.8%–2.1%, Mg 1.3%–1.4%, Ti 0.02%–0.08%, Ni 0.7%–0.9%, 0.1% ≤ Mn + Cr + Zr ≤ 0.2%; individual impurities ≤ 0.05%, total impurities ≤ 0.1%, balance Al, totaling 100%.

[0039] The novel aluminum alloy rod formulation provided by this invention incorporates three trace elements: Mn, Cr, and Zr. This addition inhibits grain recrystallization in the aluminum alloy. By adjusting the proportions of Mn, Cr, and Zr, ensuring that 0.1% ≤ Mn + Cr + Zr ≤ 0.2%, not only can recrystallization growth be suppressed, but the recrystallization ratio can also be effectively adjusted, resulting in uniform grain size. The formulation contains 0.7%–0.9% Fe, 1.8%–2.1% Cu, 1.3%–1.4% Mg, and 0.7%–0.9% Ni, with the balance being Al as the main element. By adjusting the proportions of these main elements, the mechanical and heat resistance properties of the aluminum alloy can be improved. The novel aluminum alloy rod exhibits a tensile strength ≥ 355 MPa and an elongation ≥ 8.0%, demonstrating good mechanical properties.

[0040] In one specific implementation, the diameter of the aluminum alloy rod is 20–80 mm.

[0041] According to a second aspect of the present invention, a method for preparing Al-Cu-Mg-Fe-Ni aluminum alloy rods is provided, comprising hot extruding an Al-Cu-Mg-Fe-Ni aluminum alloy ingot to obtain extruded rods:

[0042] During the hot extrusion process, the heating temperature at the head of the aluminum alloy ingot is higher than that at the tail.

[0043] The extrusion speed at the front end of the aluminum alloy ingot is greater than the extrusion speed at the rear end.

[0044] Al-Cu-Mg-Fe-Ni aluminum alloy ingots are ingots prepared by using the proportions of each component of the above-mentioned Al-Cu-Mg-Fe-Ni aluminum alloy rods, or ingots prepared by using the proportions of each component of aluminum alloy rods of grade 2A70 or grade 2D70.

[0045] This invention optimizes the extrusion process and controls the deformation energy storage during extrusion, thereby reducing the nucleation rate and growth rate of crystal nuclei, resulting in finer and more uniform grains that meet the requirements for grain use; tensile strength ≥355MPa, elongation ≥8.0%.

[0046] This invention discovers that in the extrusion process, the head of the aluminum alloy ingot is extruded first and cools down rapidly in the environment, while the tail is extruded later. The tail portion generates heat during continuous extrusion, resulting in a significant temperature difference between the earlier and later extruded aluminum alloy materials. This temperature difference leads to uneven heat distribution and grain formation within the same aluminum alloy bar, resulting in varying deformation energy storage. To overcome this extrusion defect, the hot extrusion temperature of the ingot head is increased, making it slightly higher than the hot pressurization temperature of the tail. This ensures that the temperature of the head portion after hot extrusion is similar to or the same as the temperature of the tail portion during extrusion, minimizing the temperature difference within the same aluminum alloy material and improving grain uniformity and mechanical properties. Furthermore, in addition to improving the head and tail temperatures, the extrusion speed of each part of the aluminum alloy is optimized to overcome the extrusion temperature difference. For the same reason, when using a single... At high extrusion speeds, the aluminum alloy at the head of the first extrusion cools down faster in the environment. Meanwhile, the middle and rear sections, which are being extruded in the heating cylinder, continuously generate heat due to the ongoing extrusion process. This creates a temperature difference between the first and last extruded sections, which is detrimental to the uniformity and fineness of grain crystallization. To address this, this invention designs an extrusion speed that is slightly higher for the front section of the aluminum alloy than for the rear section. By using different extrusion speeds, with a higher speed for the first section and a lower speed for the last section, the higher the extrusion speed, the more heat is generated by the aluminum alloy due to extrusion friction. This compensates for the cooling of the first section of aluminum alloy. By using two different extrusion speeds and continuously matching the products at each speed, the temperatures of the two sections of aluminum alloy can be kept similar or the same during the extrusion process, avoiding temperature differences and thus improving the crystallinity, uniformity, fineness of the grains, and the mechanical properties of the aluminum alloy.

[0047] As a specific implementation method, the Al-Cu-Mg-Fe-Ni aluminum alloy ingot is a heat-treated ingot, specifically including:

[0048] The aluminum alloy rods are prepared according to the proportion of each component, and then melted to obtain aluminum alloy ingots. The aluminum alloy ingots are then subjected to homogenization heat treatment to obtain heat-treated ingots.

[0049] In step S1 of this invention, aluminum alloy ingots are prepared using the aforementioned novel aluminum alloy rod feedstock. By adding three trace elements—Mn, Cr, and Zr—the recrystallization of grains in the aluminum alloy can be suppressed. By controlling the addition ratio of Mn, Cr, and Zr, 0.1% ≤ Mn + Cr + Zr ≤ 0.2% can not only suppress recrystallization growth but also effectively regulate the recrystallization ratio, resulting in uniform grain size. The feedstock contains 0.7%–0.9% Fe, 1.8%–2.1% Cu, 1.3%–1.4% Mg, and 0.7%–0.9% Ni, with the balance being Al, which is the main element. By adjusting the proportions of these main elements, the novel aluminum alloy rod of this invention exhibits a tensile strength ≥355 MPa and an elongation ≥8.0%, demonstrating good mechanical properties. It can improve the mechanical properties and heat resistance of aluminum alloys. Homogenization heat treatment improves the internal microstructure of the metal, eliminates casting stress, reduces segregation, and is more conducive to subsequent stretching and extrusion processes.

[0050] As a specific implementation method, the preparation method of Al-Cu-Mg-Fe-Ni aluminum alloy rods includes the following steps after the hot extrusion process:

[0051] The extruded bar is subjected to solution heat treatment to obtain a solution heat-treated bar.

[0052] The solution heat-treated bar is stretched and straightened to obtain a stretched and straightened bar.

[0053] The stretched and straightened bars were subjected to aging heat treatment to obtain Al-Cu-Mg-Fe-Ni aluminum alloy bars.

[0054] This invention prepares aluminum alloy rods by hot extrusion, and then improves the grain morphology of the rods by solution heat treatment, ensuring that the solid solution of the alloy is fully dissolved into the matrix, thus ensuring the mechanical properties of the alloy. The resulting aluminum alloy rods have a tensile strength ≥355MPa and an elongation ≥8.0%.

[0055] In a preferred embodiment, during hot extrusion, the heating temperature of the head of the aluminum alloy ingot is 5-20°C higher than that of the tail. By controlling the difference between the head hot pressing temperature and the tail hot extrusion temperature to 5-20°C, this invention can appropriately adjust the temperature of the first extruded head and the last extruded tail to achieve almost identical temperatures. This reduces deformation energy storage during extrusion and improves the uniformity of the extruded bar, resulting in further refinement and homogenization of the grains. This ensures that all parts of the same aluminum alloy bar have the same or similar heating temperature or internal heat, promoting finer and more uniform grain crystallization within the aluminum alloy, which is more conducive to improving the mechanical properties of the final product.

[0056] In a preferred embodiment, the heating temperature of the hot extrusion die is 400℃~420℃, and the heating temperature of the extrusion cylinder inside the die is 400℃~420℃. In this invention, the heating temperatures of the hot extrusion die and the extrusion cylinder are the same or similar. This temperature can be adjusted according to the characteristics of the aluminum alloy composition. It should not be too high or too low, to avoid the hot extrusion effect being unattainable if too low, and the extrusion quality being affected if too high.

[0057] In a preferred embodiment, the head heating temperature of the aluminum alloy ingot is 430℃~440℃, and the tail heating temperature is 420℃~430℃. For example, the head heating temperature is 430℃ and the tail heating temperature is 420℃, or the head heating temperature is 440℃ and the tail heating temperature is 420℃, or the head heating temperature is 440℃ and the tail heating temperature is 430℃, etc. This invention raises the head temperature to above 430℃ and controls the tail temperature to above 420℃ within a wide hot extrusion range, ensuring the head temperature is always higher than the tail temperature. This ensures that the head and tail temperatures are similar or the same during extrusion, achieving overall temperature balance in the same aluminum alloy material. Reducing temperature differences during hot extrusion further improves the crystallization performance of the aluminum alloy, resulting in finer and more uniform grains, and also promotes the mechanical properties of the aluminum alloy.

[0058] In a preferred embodiment, during hot extrusion, the half-length of the aluminum alloy ingot closest to the head is designated as the front section, and the half-length of the aluminum alloy ingot closest to the tail is designated as the rear section. This invention divides the aluminum alloy into two equal sections, designated as the front section and the rear section according to the order in which they are hot-extruded, and precisely controls the different extrusion speeds for each of these sections. This method of equal segmentation allows for more accurate measurement of the heat generated in each section during the extrusion process through different extrusion speeds, which is beneficial for homogenizing and refining the aluminum alloy grains and achieving uniform mechanical properties.

[0059] In a preferred embodiment, the extrusion speed of the first stage is 1.5–2.0 mm / s, and the extrusion speed of the second stage is 0.5–1.0 mm / s. Based on the heat generated by the friction during extrusion of the aluminum alloy, the hot extrusion temperature, and the dissolution or leaching of metal elements in the aluminum matrix, this invention appropriately designs two different extrusion speeds to balance the heat generated in each stage during extrusion, thus preventing the dissolution of metal elements from the aluminum matrix. This invention designs the extrusion speeds of the first and second stages in a gradient progression pattern, with the first stage extrusion speed being faster at 1.5–2.0 mm / s and the second stage controlled at 0.5–1.0 mm / s. This gradient extrusion speed can balance the heat in the aluminum alloy during extrusion, reduce temperature differences, and minimize the dissolution of metal components from the aluminum matrix, further promoting the crystallization effect and mechanical properties of the aluminum alloy.

[0060] In a preferred embodiment, the solution heat treatment includes a first solution heat treatment and a second solution heat treatment; the first solution heat treatment process includes: a heating rate of 90℃ / h to 160℃ / h, a temperature of 440℃ to 460℃, and a holding time of 0.5h to 1.0h; the second solution heat treatment process includes: a heating rate of 500℃ / h to 1000℃ / h, a temperature of 530℃ to 540℃, and a holding time of 1.5h to 2.5h.

[0061] This invention employs a two-stage solid solution process. The first-stage solid solution process can adjust the grain morphology, while the second-stage solid solution process, under the premise that the grain morphology meets the requirements, ensures that the solid solution of the alloy is fully dissolved into the matrix, thus guaranteeing the mechanical properties of the alloy.

[0062] As a specific implementation method, the present invention involves stretching and straightening an aluminum alloy after solution heat treatment, wherein the stretching and straightening amount is ≤2.0%.

[0063] In one specific implementation, the aging heat treatment temperature is 195℃~205℃, and the holding time is 8h~12h. By employing the above-mentioned temperature and time for artificial aging treatment, this invention can eliminate internal stress, stabilize the microstructure and structure of aluminum alloy bars, and improve their mechanical properties. For example, the tensile strength of the aluminum alloy bars of this invention is ≥355MPa, and the elongation is ≥8.0%.

[0064] As a more specific embodiment, the present invention provides a method for preparing Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars with a uniform fine-grained structure, comprising the following steps:

[0065] (1) The prepared aluminum alloy round ingot is subjected to homogenization heat treatment to obtain a homogenized heat-treated aluminum alloy round ingot.

[0066] (2) After milling the aluminum alloy round ingot obtained in step (1), induction heating is performed. The heating temperature of the head end of the round ingot is 430℃~440℃; the heating temperature of the tail end is 420℃~430℃, and the heating temperature of the tail end is 10℃~20℃ lower than that of the head end.

[0067] (3) The mold structure is a flat mold with a working belt length of 2-3 mm. The mold is heated to 400℃-420℃, the extrusion cylinder is heated to 400℃-420℃, the extrusion pad is cooled with liquid nitrogen, and then the aluminum alloy round ingot processed in step (2) is placed in. The extrusion speed of the first 1 / 2 length of the round ingot is 1.5-2.0 mm / s, and the extrusion speed of the second 1 / 2 length is 0.5-1.0 mm / s to obtain aluminum alloy rods;

[0068] (4) The aluminum alloy rods obtained in step (3) are subjected to solution heat treatment. The solution heat treatment regime is as follows: the heating rate is 90℃ / h~160℃ / h, the temperature is 440℃~460℃, and the holding time is 0.5h~1.0h; the second-stage solution heating rate is 500℃ / h~1000℃ / h, the temperature is 530℃~540℃, and the holding time is 1.5h~2.5h.

[0069] (5) The bar material processed in step (4) is stretched and straightened, and the amount of stretching and straightening is ≤2.0%;

[0070] (6) The aluminum alloy bar after stretching and straightening in step (5) is subjected to artificial aging heat treatment. The artificial aging heat treatment temperature is 195℃~205℃ and the holding time is 8h~12h to obtain Al-Cu-Mg-Fe-Ni aluminum alloy extruded bar with uniform fine grain structure.

[0071] The Al-Cu-Mg-Fe-Ni aluminum alloy rods provided by this invention or the Al-Cu-Mg-Fe-Ni aluminum alloy rods prepared by the above method have finer grains, more uniform grain distribution, tensile strength ≥355MPa, elongation ≥8.0%, and good heat resistance, and can be well applied in aerospace materials.

[0072] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0073] Example 1

[0074] A method for preparing Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars includes the following steps:

[0075] The aluminum alloy rod is formulated according to the following weight percentages: Si 0.01%, Fe 0.7%, Cu 1.8%, Mg 1.3%, Ti 0.02%, Ni 0.7%, Mn 0.06%, Cr 0.04%, Zr 0.06%, with individual impurities ≤0.05% and total impurities ≤0.15%, the balance being Al, totaling 100%.

[0076] Aluminum alloy round ingots are obtained by smelting aluminum ingots, Mg ingots, Al-Cu master alloys, Fe-Ni alloys, Al-Mn alloys, Al-Cr alloys, and Al-Zr alloys. After homogenization and heat treatment, the round ingots are extruded. The extrusion die structure is a flat die with a working strip length of 2 mm. The extrusion process is as follows: the head end of the round ingot is electromagnetically heated to 430℃, the tail end to 420℃, the extrusion cylinder temperature is 400℃, the extrusion die temperature is 400℃, the extrusion pad is cooled with liquid nitrogen, the extrusion speed for the first half of the round ingot is 1.5 mm / s, and the extrusion speed for the last half of the round ingot is 0.5 mm / s, resulting in extruded bars. The obtained extruded bars were subjected to solution heat treatment. The solution treatment regime was as follows: the first stage solution treatment heating rate was 90℃ / h, the solution temperature was 440℃, and the holding time was 0.5h; the second stage solution treatment heating rate was 1000℃ / h, the solution temperature was 530℃, and the holding time was 1.5h. After solution heat treatment, the bars were water-cooled to room temperature. The bars after solution heat treatment were then stretched and straightened, with a straightening amount ≤2.0%. The straightened extruded bars were then subjected to artificial aging heat treatment at 195℃ for 8h, followed by cooling to room temperature using air as the cooling medium. This yielded Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars, whose low-magnification microstructure is as follows: Figure 1 As shown, the high-magnification tissue structure is as follows Figure 4 As shown in Table 1, the results of the microstructure and properties test of the extruded bars are presented.

[0077] Example 2

[0078] A method for preparing Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars includes the following steps:

[0079] Si 0.01%, Fe 0.8%, Cu 1.9%, Mg 1.4%, Ti 0.06%, Ni 0.8%, Mn 0.04%, Cr 0.03%, Zr 0.05%, individual impurities ≤0.05%, total impurities ≤0.15%, balance Al, total 100%;

[0080] Aluminum alloy round ingots are obtained by smelting aluminum ingots, Mg ingots, Al-Cu master alloys, Fe-Ni alloys, Al-Mn alloys, Al-Cr alloys, and Al-Zr alloys. After homogenization and heat treatment, the round ingots are extruded. The extrusion die is a flat die with a working strip length of 3 mm. The extrusion process is as follows: the ingot head is electromagnetically heated to 435℃, the tail end to 430℃, the extrusion cylinder and die are heated to 410℃, the extrusion pad is cooled with liquid nitrogen, and the extrusion speed for the first half of the ingot length is 1.75 mm / s, and the extrusion speed for the last half of the ingot length is 0.75 mm / s, yielding extruded bars. The obtained extruded bars were subjected to solution heat treatment. The solution treatment regime was as follows: the first stage solution treatment heating rate was 125℃ / h, the solution temperature was 450℃, and the holding time was 1h; the second stage solution treatment heating rate was 750℃ / h, the solution temperature was 535℃, and the holding time was 2h. After solution heat treatment, the bars were water-cooled to room temperature. The bars after solution heat treatment were then stretched and straightened, with a straightening amount ≤2.0%. The straightened extruded bars were then subjected to artificial aging heat treatment at a temperature of 200℃ for 10h, and cooled to room temperature using air as the cooling medium. This yielded Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars, whose low-magnification microstructure is as follows: Figure 1 As shown, the high-magnification tissue structure is as follows Figure 4 As shown in Table 1, the results of the microstructure and properties test of the extruded bars are presented.

[0081] Example 3

[0082] The composition is as follows: Si 0.01%, Fe 0.9%, Cu 2.1%, Mg 1.35%, Ti 0.08%, Ni 0.9%, Mn 0.03%, Cr 0.025%, Zr 0.045%, with individual impurities ≤0.05% and total impurities ≤0.15%, with the balance being Al, totaling 100%.

[0083] Aluminum alloy round ingots are obtained by smelting aluminum ingots, Mg ingots, Al-Cu master alloys, Fe-Ni alloys, Al-Mn alloys, Al-Cr alloys, and Al-Zr alloys. After homogenization and heat treatment, the round ingots are extruded. The extrusion die is a flat die with a working strip length of 2.5 mm. The extrusion process is as follows: the head end of the round ingot is electromagnetically heated to 440℃, the tail end to 425℃, the extrusion cylinder is heated to 420℃, the extrusion die is heated to 420℃, the extrusion pad is cooled with liquid nitrogen, the extrusion speed for the first half of the round ingot is 2 mm / s, and the extrusion speed for the last half of the round ingot is 1 mm / s, resulting in extruded bars. The obtained extruded bars were subjected to solution heat treatment. The solution treatment process was as follows: the first stage of solution treatment had a heating rate of 160℃ / h, a solution temperature of 460℃, and a holding time of 0.5h; the second stage of solution treatment had a heating rate of 500℃ / h, a solution temperature of 540℃, and a holding time of 2.5h. After solution heat treatment, the bars were water-cooled to room temperature. The bars after solution heat treatment were then stretched and straightened, with a straightening amount ≤2.0%. The straightened extruded bars were then subjected to artificial aging heat treatment at a temperature of 205℃ and a holding time of 12h. After cooling to room temperature, the cooling medium was air. The microstructure and properties of the obtained Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars are shown in Table 1.

[0084] Example 4

[0085] Si 0.01%, Fe 0.7%, Cu 1.9%, Mg 1.3%, Ti 0.02%, Ni 0.7%, Mn 0.08%, Cr 0.05%, Zr 0.07%, individual impurities ≤0.05%, total impurities ≤0.15%, balance Al, total 100%;

[0086] Aluminum alloy round ingots are obtained by smelting aluminum ingots, Mg ingots, Al-Cu master alloys, Fe-Ni alloys, Al-Mn alloys, Al-Cr alloys, and Al-Zr alloys. After homogenization and heat treatment, the round ingots are extruded. The extrusion die is a flat die with a working strip length of 3 mm. The extrusion process is as follows: the head end of the round ingot is electromagnetically heated to 430℃, the tail end to 425℃, the extrusion cylinder to 415℃, the extrusion die to 415℃, and the extrusion pad is cooled with liquid nitrogen. The extrusion speed for the first half of the round ingot is 1.5 mm / s, and the extrusion speed for the last half is 0.5 mm / s, yielding extruded bars. The obtained extruded bars were subjected to solution heat treatment. The solution treatment process was as follows: the first stage solution treatment heating rate was 125℃ / h, the solution temperature was 445℃, and the holding time was 1h; the second stage solution treatment heating rate was 500℃ / h, the solution temperature was 530℃, and the holding time was 2.5h. After solution heat treatment, the bars were water-cooled to room temperature. The bars after solution heat treatment were stretched and straightened, with a stretching straightening amount ≤2.0%. The straightened extruded bars were then subjected to artificial aging heat treatment at a temperature of 195℃ and a holding time of 8h. The bars were then cooled to room temperature using air as the cooling medium to obtain Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars. The microstructure and property test results of the obtained extruded bars are shown in Table 1.

[0087] Example 5

[0088] Si 0.01%, Fe 0.7%, Cu 1.9%, Mg 1.3%, Ti 0.02%, Ni 0.9%, Mn 0.06%, Cr 0.04%, Zr 0.06%, individual impurities ≤0.05%, total impurities ≤0.15%, balance Al, total 100%;

[0089] Aluminum alloy round ingots are obtained by smelting aluminum ingots, Mg ingots, Al-Cu master alloys, Fe-Ni alloys, Al-Mn alloys, Al-Cr alloys, and Al-Zr alloys. After homogenization and heat treatment, the round ingots are extruded. The extrusion die is a flat die with a working strip length of 2.5 mm. The extrusion process is as follows: the head end of the round ingot is electromagnetically heated to 435℃, the tail end to 420℃, the extrusion cylinder temperature is 415℃, the extrusion die temperature is 415℃, the extrusion pad is cooled with liquid nitrogen, the extrusion speed for the first half of the round ingot is 2 mm / s, and the extrusion speed for the last half of the round ingot is 0.5 mm / s, resulting in extruded bars. The obtained extruded bars were subjected to solution heat treatment. The solution treatment process was as follows: the first stage solution treatment heating rate was 125℃ / h, the solution temperature was 450℃, and the holding time was 1h; the second stage solution treatment heating rate was 500℃ / h, the solution temperature was 535℃, and the holding time was 2h. After solution heat treatment, the bars were water-cooled to room temperature. The bars after solution heat treatment were stretched and straightened, with a stretch straightening amount ≤2.0%. The straightened extruded bars were then subjected to artificial aging heat treatment at a temperature of 195℃ and a holding time of 12h. The bars were then cooled to room temperature using air as the cooling medium to obtain Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars. The microstructure and property test results of the obtained extruded bars are shown in Table 1.

[0090] Example 6

[0091] Si 0.01%, Fe 0.9%, Cu 2.1%, Mg 1.5%, Ti 0.08%, Ni 0.8%, Mn 0.08%, Cr 0.05%, Zr 0.07%, individual impurities ≤0.05%, total impurities ≤0.15%, balance Al, total 100%;

[0092] Aluminum alloy round ingots are obtained by smelting aluminum ingots, Mg ingots, Al-Cu master alloys, Fe-Ni alloys, Al-Mn alloys, Al-Cr alloys, and Al-Zr alloys. After homogenization and heat treatment, the round ingots are extruded. The extrusion die is a flat die with a working strip length of 2 mm. The extrusion process is as follows: the ingot head is electromagnetically heated to 440℃, the tail end to 430℃, the extrusion cylinder and die are both heated to 405℃, and the extrusion pad is cooled with liquid nitrogen. The extrusion speed for the first half of the ingot length is 1.75 mm / s, and the extrusion speed for the last half is 1 mm / s, yielding extruded bars. The obtained extruded bars were subjected to solution heat treatment. The solution treatment process was as follows: the first stage solution treatment heating rate was 135℃ / h, the solution temperature was 455℃, and the holding time was 0.5h; the second stage solution treatment heating rate was 750℃ / h, the solution temperature was 533℃, and the holding time was 1h. After solution heat treatment, the bars were water-cooled to room temperature. The bars after solution heat treatment were stretched and straightened, with a straightening amount ≤2.0%. The straightened extruded bars were then subjected to artificial aging heat treatment at a temperature of 205℃ and a holding time of 8h. The bars were then cooled to room temperature using air as the cooling medium to obtain Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars. The microstructure and property test results of the obtained extruded bars are shown in Table 1.

[0093] Comparative Example 1

[0094] A method for preparing Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars includes the following steps:

[0095] The aluminum alloy rod is formulated according to the following weight percentages: Si 0.01%, Fe 0.7%, Cu 1.8%, Mg 1.3%, Ti 0.02%, Ni 0.7%, Cr 0.2%, with individual impurities ≤0.05% and total impurities ≤0.15%, the remainder being Al.

[0096] Aluminum alloy round ingots are obtained by melting aluminum ingots, Mg ingots, Al-Cu master alloys, Fe-Ni alloys, Al-Cr alloys, etc. After homogenization and heat treatment, the round ingots are extruded. The extrusion die structure is a flat die with a working strip length of 2mm. The extrusion process is as follows: the head end of the round ingot is electromagnetically heated to 440℃, the tail end to 420℃, the extrusion cylinder temperature is 380℃, the extrusion die temperature is 380℃, the extrusion pad is cooled with liquid nitrogen, the extrusion speed for the first half of the round ingot is 1.5mm / s, and the extrusion speed for the last half of the round ingot is 0.5mm / s, resulting in extruded bars. The obtained extruded bars were subjected to solution heat treatment. The solution treatment regime was as follows: the first stage solution treatment heating rate was 455℃ / h, the solution temperature was 400℃, and the holding time was 1h; the second stage solution treatment heating rate was 1000℃ / h, the solution temperature was 538℃, and the holding time was 2h. After solution heat treatment, the bars were water-cooled to room temperature. The bars after solution heat treatment were then stretched and straightened, with a straightening amount ≤2.0%. The straightened extruded bars were then subjected to artificial aging heat treatment at a temperature of 205℃ and a holding time of 8h. After cooling to room temperature, air was used as the cooling medium to obtain Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars. The low-magnification microstructure is as follows: Figure 3 As shown, the high-magnification tissue structure is as follows Figure 6 As shown in Table 1, the results of the microstructure and properties test of the extruded bars are presented.

[0097] Comparative Example 2

[0098] A method for preparing Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars includes the following steps:

[0099] The aluminum alloy rod is formulated according to the following weight percentages: Si 0.01%, Fe 0.8%, Cu 1.9%, Mg 1.75%, Ti 0.06%, Ni 0.8%, Mn 0.18%, Cr 0.1%, Zr 0.12%, with individual impurities ≤0.05% and total impurities ≤0.15%, the remainder being Al.

[0100] Aluminum alloy round ingots are obtained by smelting aluminum ingots, Mg ingots, Al-Cu master alloys, Fe-Ni alloys, Al-Mn alloys, Al-Cr alloys, and Al-Zr alloys. After homogenization and heat treatment, the round ingots are extruded. The extrusion die structure is a flat die with a working strip length of 5 mm. The extrusion process is as follows: the head end of the round ingot is electromagnetically heated to 450℃, the tail end to 440℃, the extrusion cylinder temperature is 390℃, the extrusion die temperature is 390℃, the extrusion pad is cooled with liquid nitrogen, the extrusion speed for the first half of the round ingot is 1 mm / s, and the extrusion speed for the last half of the round ingot is 1.5 mm / s, resulting in extruded bars. The obtained extruded bars were subjected to solution heat treatment. The solution treatment process was as follows: the first stage of solution treatment had a heating rate of 1000℃ / h, a solution temperature of 480℃, and a holding time of 2h; the second stage of solution treatment had a heating rate of 1000℃ / h, a solution temperature of 520℃, and a holding time of 3h. After solution heat treatment, the bars were water-cooled to room temperature. The bars after solution heat treatment were then stretched and straightened, with a straightening amount ≤2.0%. The straightened extruded bars were then subjected to artificial aging heat treatment at a temperature of 170℃ and a holding time of 12h. After cooling to room temperature, air was used as the cooling medium to obtain Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars. The microstructure and property test results of the obtained extruded bars are shown in Table 1.

[0101] Comparative Example 3

[0102] A method for preparing Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars includes the following steps:

[0103] The aluminum alloy rod is formulated according to the following weight percentages: Si 0.01%, Fe 0.9%, Cu 2.1%, Mg 1.5%, Ti 0.08%, Ni 0.9%, Mn 0.06%, Cr 0.04%, Zr 0.06%, with individual impurities ≤0.05% and total impurities ≤0.15%, the remainder being Al.

[0104] Aluminum alloy round ingots are obtained by smelting aluminum ingots, Mg ingots, Al-Cu master alloys, Fe-Ni alloys, Al-Mn alloys, Al-Cr alloys, and Al-Zr alloys. After homogenization and heat treatment, the round ingots are extruded. The extrusion die structure is a flat die with a working strip length of 6 mm. The extrusion process is as follows: electromagnetic heating of the round ingot to 400℃, extrusion cylinder temperature to 400℃, extrusion die temperature to 400℃, liquid nitrogen cooling of the extrusion pad, extrusion speed of 1 mm / s for the first half of the round ingot length, and extrusion speed of 1.5 mm / s for the second half of the round ingot length, to obtain extruded bars. The obtained extruded bars were subjected to solution heat treatment. The solution treatment process was as follows: the first stage solution treatment heating rate was 160℃ / h, the solution temperature was 420℃, and the holding time was 3h; the second stage solution treatment heating rate was 340℃ / h, the solution temperature was 545℃, and the holding time was 6h. After solution heat treatment, the bars were water-cooled to room temperature. The bars after solution heat treatment were stretched and straightened, with a stretching straightening amount ≤2.0%. The straightened extruded bars were then subjected to artificial aging heat treatment at a temperature of 200℃ and a holding time of 14h. The bars were then cooled to room temperature using air as the cooling medium to obtain Al-Cu-Mg-Fe-Ni aluminum alloy extruded bars. The microstructure and property test results of the obtained extruded bars are shown in Table 1.

[0105] Table 1. Results of microstructure and property testing of extruded bars obtained in Examples 1-6 and Comparative Examples 1-3

[0106]

[0107]

[0108] Table 1 shows the test results, indicating that the Al-Cu-Mg-Fe-Ni aluminum alloy rods prepared in Examples 1-6 of this invention have finer grains, more uniform grain distribution, tensile strength ≥355MPa (375-432MPa), and elongation ≥8.0% (8.5-15.8%). In contrast, Comparative Examples 1-3 have coarse grains and / or uneven grain distribution, with tensile strengths ranging from 320-345MPa and elongations around 10.5-15.9%. The comparison shows that the tensile strength of the aluminum alloy rods of this invention is 30-90MPa higher than that of the aluminum alloy rods of Comparative Examples 1-3. Therefore, the mechanical properties of the aluminum alloy rods prepared in these examples are significantly superior to those prepared in Comparative Examples 1-3.

[0109] The internal microstructure analysis images of the aluminum alloy bars prepared in the various embodiments and comparative examples show that, at the same scanning magnification, Figures 1-2 and Figure 3 In comparison, the aluminum alloy bars of Examples 1-2 of the present invention have finer grains and more uniform grain distribution in their cross-sections, while the bars of Comparative Examples 1-3 have rough cross-sections, with varying grain sizes and uneven grain distribution. Figures 4-5 and Figure 6In comparison, the embodiments of the present invention Figures 4-5 The metal grains in the core and edges of the medium-sized bar are significantly finer and more uniformly distributed, as shown in Comparative Examples 1-3. Figure 6 The metal grains in the core and edges of the medium bar are relatively larger and unevenly distributed.

[0110] The aluminum alloy bar formulation of Comparative Example 1 introduced only 0.2% Cr as a trace element, while the aluminum alloy bar formulations of Examples 1 and 2 of this invention introduced 0.1% ≤ Mn + Cr + Zr ≤ 0.2% as trace elements. As shown in Table 1, the performance and internal structure test results of the two aluminum alloy bars indicate that this invention introduces three trace elements—Mn, Cr, and Zr—in a specific proportion and with specific ratios between them. Furthermore, combined with the two different extrusion speeds designed in this invention, the metal grains can be made finer and more uniformly distributed, further improving the mechanical properties of the bars, such as tensile strength and elongation.

[0111] In Comparative Example 2, three trace elements, Mn, Cr, and Zr, were introduced into the ingredients, but their total proportion was 0.4%. During the extrusion process, the extrusion speed of the ingot was 1 mm / s in the first stage and 0.5 mm / s in the second stage, meaning the first stage extrusion speed was lower than the second stage. The first solution heating rate was 1000℃ / h. Performance and internal structure testing results showed that the total amount of Mn, Cr, and Zr was controlled within a certain range, such as 0.1% ≤ Mn + Cr + Zr ≤ 0.2%, combined with specific two-stage extrusion speeds. The extrusion speed at the front stage is greater than that at the rear stage. Only by adopting the above method can the metal grains be finer, more uniformly distributed, and have better mechanical properties. In particular, although Comparative Example 2 also uses two different extrusion speeds in two stages, the relative relationship between the two extrusion speeds is not designed reasonably, and the purpose of improving mechanical properties is not achieved. Similarly, although the total proportion of the three trace elements introduced in Comparative Example 3 is the same as that in the embodiment of the present invention, the grain distribution and mechanical properties still cannot be improved due to the unreasonable design of the relative relationship between the extrusion speeds at the front and rear stages. The design of this invention, where the front section is larger than the rear section, involves the head of the front section being extruded first, followed by the tail section. The temperature of the first section is lower, while the temperature of the later section increases due to extrusion friction and heating, resulting in a larger temperature difference between the head and tail. This affects the uniformity of the metal grain size distribution and the mechanical properties of the rod. By designing the extrusion speed, this invention ensures that the temperatures of the two sections are basically the same or similar during the extrusion process, resulting in a more balanced heat distribution throughout the rod. This leads to finer and more uniform metal grain size during extrusion, further improving its tensile strength, elongation, and other mechanical properties.

[0112] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An Al-Cu-Mg-Fe-Ni aluminum alloy rod, characterized in that, The aluminum alloy bar comprises the following components by weight percentage: Si ≤0.02%, Fe 0.7%~0.9%, Cu 1.8%~2.1%, Mg 1.3%~1.4%, Ti 0.02%~0.08%, Ni 0.7%~0.9%, 0.1%≤ Mn+Cr+Zr≤ 0.2%; Individual impurities ≤0.05%, total impurities ≤0.1%, balance Al, totaling 100%; The method for preparing the aluminum alloy rod includes: hot extruding an Al-Cu-Mg-Fe-Ni aluminum alloy ingot to obtain an extruded rod; subjecting the extruded rod to solution heat treatment to obtain a solution-heat-treated rod; stretching and straightening the solution-heat-treated rod to obtain a stretch-straightened rod; and aging heat treatment the stretch-straightened rod to obtain the Al-Cu-Mg-Fe-Ni aluminum alloy rod. During the hot extrusion process, the head of the aluminum alloy ingot is heated to 430℃~440℃, and the tail of the aluminum alloy ingot is heated to 420℃~430℃. The head heating temperature is 5~20℃ higher than the tail heating temperature. The half-length of the aluminum alloy ingot closest to the head is called the front section, and the half-length of the aluminum alloy ingot closest to the tail is called the rear section. The extrusion speed of the front section of the aluminum alloy ingot is greater than the extrusion speed of the rear section. The solution heat treatment includes a first solution heat treatment and a second solution heat treatment; the first solution heat treatment process includes: a heating rate of 90℃ / h ~ 160℃ / h, a temperature of 440℃ ~ 460℃, and a holding time of 0.5h ~ 1.0h; the second solution heat treatment process includes: a heating rate of 500℃ / h ~ 1000℃ / h, a temperature of 530℃ ~ 540℃, and a holding time of 1.5h ~ 2.5h.

2. The Al-Cu-Mg-Fe-Ni aluminum alloy rod according to claim 1, characterized in that, The Al-Cu-Mg-Fe-Ni aluminum alloy ingot is a heat-treated ingot, specifically comprising: According to the proportion of each component in the aluminum alloy bar, the aluminum alloy ingot is obtained by smelting. The aluminum alloy ingot is subjected to homogenization heat treatment to obtain the heat-treated ingot.

3. The Al-Cu-Mg-Fe-Ni aluminum alloy rod according to claim 1 or 2, characterized in that, The heating temperature of the hot extrusion die is 400℃~420℃, and the heating temperature of the extrusion cylinder inside the die is 400℃~420℃.

4. The Al-Cu-Mg-Fe-Ni aluminum alloy rod according to claim 1 or 2, characterized in that, The extrusion speed of the front section is 1.5~2.0 mm / s, and the extrusion speed of the rear section is 0.5~1.0 mm / s.

5. The Al-Cu-Mg-Fe-Ni aluminum alloy rod according to claim 1 or 2, characterized in that, The hot extrusion process uses a flat die; the working strip length of the die is 2~3mm. And / or, during the stretching and straightening process, the stretching and straightening amount is ≤2.0%; And / or, the temperature of the aging heat treatment is 195℃~205℃, and the holding time of the aging heat treatment is 8h~12h.

6. The application of an Al-Cu-Mg-Fe-Ni aluminum alloy rod according to any one of claims 1 to 5 in aerospace materials.

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