High-strength heat-resistant 2000 series aluminum alloy as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of aluminum alloys, and particularly relates to a high-strength heat-resistant 2000 series aluminum alloy as well as a preparation method and application thereof. The high-strength heat-resistant 2000 series aluminum alloy comprises the following components in percentage by mass: 4.0%-5.0% of Cu, 1.5%-2.0% of Mg, 0.30%-1.00% of Mn, 0.30%-0.60% of Zn, 0.10%-0.50% of Cr, 0.10%-0.30% of Zr, 0.10%-0.20% of Ti and the balance of Al and inevitable impurities. The Mn / Cr ratio in the alloy is 2.0-2.8, and a Cr-containing T phase with the volume fraction not lower than 3% is formed. The tensile strength of the alloy at room temperature and 200 DEG C is improved by 19% and 24% respectively, and the percentage elongation after fracture is improved by more than 1 / 4 and more than 1 / 5 respectively. And the alloy does not contain expensive elements such as Ag and rare earth, and is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloys, and in particular relates to a high-strength and heat-resistant 2000 series aluminum alloy and a preparation method and application thereof. Background Art

[0002] At present, 2000 series aluminum alloys have high strength, good damage resistance and good heat resistance, and are important materials for manufacturing key aviation metal components. Alloys such as 2024, 2524, 2519, and 2618 are currently representative high-performance 2000 series aluminum alloys. The room temperature tensile strength under industrial production conditions can reach 440-480MPa, and the elongation after fracture can reach 10%-18%. Aircraft skins, landing gear hubs and other key aviation components are subject to complex stresses during service and need to withstand high temperatures for a short time. Improving the strength and plasticity of 2000 series aluminum alloys at room temperature and high temperature is an important challenge facing the development of large-scale, high-reliability, and long-life aviation equipment.

[0003] Precipitation strengthening is the main strengthening method of 2000 series aluminum alloys. At room temperature, θ′ (Al2Cu) phase, S (Al2CuMg) phase and T (AlCu3Mn2) phase are the main strengthening phases of 2000 series aluminum alloys. Researchers often use composition optimization methods to control the type, size and density of precipitation phases, while enhancing the precipitation strengthening effect, effectively refining the grains, thereby simultaneously improving the room temperature strength and plasticity of the alloy. However, under higher temperature conditions, the above-mentioned strengthening phases will coarsen and the strengthening effect will be significantly reduced, resulting in insufficient high temperature strength. Adding specific elements to the alloy is an effective way to solve this problem. By adding elements such as Ag and Ce, phases such as Ω, Al 11 The high temperature strengthening phase of Ce3 phase improves the high temperature strength of the alloy. However, the improvement of room temperature strength by high temperature strengthening is not significant, and even deteriorates. The addition of expensive elements also greatly increases the raw material cost of the alloy. How to simultaneously improve the room temperature and high temperature mechanical properties of 2000 series aluminum alloys is an important problem currently faced by alloy design.

[0004] The present invention innovatively proposes a new idea of ​​changing the T phase structure by adding an appropriate amount of Cr element, forming a large number of multiple twin T phases in the alloy, improving its stability at high temperature, and achieving simultaneous improvement of the room temperature and high temperature mechanical properties of the alloy. There are few related studies on adding Cr elements in 2000 series aluminum alloys. After searching, Li Yuqian (Li Yuqian. Effect of composite addition of Cr and Yb on the structure and mechanical properties of aluminum alloys [D]. Changsha: Central South University, 2013.) added Cr elements to 2519A aluminum alloy to form Al7Cr strengthening phase, which hindered dislocation movement and grain boundary migration, and improved the room temperature and high temperature mechanical properties of the alloy. Patent CN109898000 A discloses a 2000 series aluminum alloy with composite addition of Cr and Mo elements, which also forms Al7Cr strengthening phase, can pin dislocations at high temperature, and improve the high temperature mechanical properties of the alloy. Lei Zhengping (Lei Zhengping. Effect of alloying elements Mg and Cr on properties and structure of 5052 aluminum alloy [J]. Aluminum Processing, 2012, (1): 4-8.) Adding Cr element to 5052 series aluminum alloy will also form Al7Cr strengthening phase, which improves the room temperature mechanical properties of the alloy by inhibiting recrystallization. Patent CN 104294096 A discloses an Al-Fe-Cu-Mg alloy for cables with added Cr element, which forms Al7 (Cr, Fe) strengthening phase, hinders the nucleation and growth process of recrystallization, refines the grains, and improves the elongation and fatigue bending resistance of the alloy. The above report is completely different from the technical idea of ​​changing the T phase structure by adding Cr element proposed in the present invention. The technical point of the present invention is that while adding Cr, the content of Mn, the main element forming the T phase, is reasonably controlled to promote the formation of Cr-containing multiple twin T phases. Summary of the invention

[0005] The invention discloses a high-strength and heat-resistant 2000 series aluminum alloy and a preparation method and application thereof, so as to solve the problems in the prior art or other potential arbitrary problems.

[0006] To solve the problems encountered in the prior art, the technical solution of the present invention is: a high-strength and heat-resistant 2000 series aluminum alloy having the following chemical composition (mass percentage): 4.0%-5.0% Cu, 1.5%-2.0% Mg, 0.30%-1.00% Mn, 0.30%-0.60% Zn, 0.10%-0.50% Cr, 0.10%-0.30% Zr, 0.10%-0.20% Ti, and the balance being Al and unavoidable impurities.

[0007] Furthermore, the high-strength and heat-resistant 2000 series aluminum alloy contains both Mn and Cr elements, and the Mn / Cr ratio is 2.0-2.8, and can form a Cr-containing T phase with a volume fraction of not less than 3%.

[0008] Furthermore, the Cr-containing T phase has a multiple twin structure.

[0009] Another object of the present invention is to provide a method for preparing the above-mentioned high-strength and heat-resistant 2000 series aluminum alloy, which specifically comprises the following steps:

[0010] S1) weighing each alloy raw material according to the designed ratio, melting and casting to obtain an ingot, the melting temperature is 700-750° C., and the casting temperature is 700-720° C.;

[0011] S2) homogenizing the ingot obtained in S1), and then air-cooling the ingot to room temperature;

[0012] S3) hot extruding or hot rolling the ingot after the homogenization treatment in S2);

[0013] S4) performing a two-stage solid solution treatment on the aluminum material after the heat treatment in S3), and then quenching in water;

[0014] S5) performing aging treatment on the aluminum material after the solid solution treatment in S4), wherein the aging treatment process is as follows: heating to 150-170° C., keeping the temperature for 20-30 hours, and obtaining a high-strength and heat-resistant 2000 series aluminum alloy after cooling.

[0015] Furthermore, the specific process of the homogenization treatment in S2) is: firstly heating to 400-450°C and keeping warm for 20-30h; then heating to 480-510°C and keeping warm for 20-30h.

[0016] Further, the process parameters of hot extrusion in S3) are: ingot heating temperature is 380-420°C, heating time is 2-4h; extrusion ratio is 9-50;

[0017] The process parameters of hot rolling are as follows: the heating temperature of the ingot is 380-420°C, the heating time is 2-4h; the total deformation of rolling is 50%-90%.

[0018] Furthermore, the process of the two-stage solution treatment in S4) is: firstly heating to 490-500°C and keeping warm for 1-2h; then heating to 500-510°C and keeping warm for 1-2h.

[0019] Furthermore, the high-strength and heat-resistant 2000 series aluminum alloy prepared by the method has a tensile strength of 550-590 MPa at room temperature and an elongation of 16.0%-19.0%; a tensile strength of 440-480 MPa at 200°C and an elongation of 17.0%-20.0%; and a tensile strength of 190-220 MPa at 300°C and an elongation of 17.0%-20.0%.

[0020] One of the above-mentioned high-strength and heat-resistant 2000 series aluminum alloys is used in the aerospace field.

[0021] The beneficial effects of the present invention are:

[0022] (1) Compared with the currently leading 2524 aluminum alloy, the tensile strength of the aluminum alloy of the present invention at room temperature and 200°C is increased by 19% and 24%, respectively, and the elongation after fracture is increased by more than 1 / 4 and more than 1 / 5, respectively.

[0023] (2) Compared with the tensile properties of the heat-resistant 2618 aluminum alloy at 200°C, the elongation after fracture of the aluminum alloy of the present invention is basically the same, while the tensile strength is increased by about 50%.

[0024] (3) The aluminum alloy of the present invention can be manufactured by conventional processes: casting → homogenization → hot extrusion / hot rolling → solution treatment → aging treatment, and the alloy does not contain expensive elements such as Ag and rare earth, and is suitable for large-scale industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the low-magnification morphology of multiple twin T phases in a high-strength and heat-resistant 2000 series aluminum alloy of the present invention;

[0026] Figure 2 A schematic diagram of the high-magnification morphology and composition analysis of multiple twin T phases in a high-strength and heat-resistant 2000 series aluminum alloy of the present invention;

[0027] Figure 3 It is a schematic diagram of the tensile curves at different temperatures of a high-strength and heat-resistant 2000 series aluminum alloy of the present invention. DETAILED DESCRIPTION

[0028] In order to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with embodiments.

[0029] It should be clear that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0031] The invention discloses a high-strength heat-resistant 2000 series aluminum alloy. The mass percentage of each component element of the high-strength heat-resistant 2000 series aluminum alloy is as follows: Cu is 4.0%-5.0%, Mg is 1.5%-2.0%, Mn is 0.30%-1.00%, Zn is 0.30%-0.60%, Cr is 0.10%-0.50%, Zr is 0.10%-0.30%, Ti is 0.10%-0.20%, and the balance is Al and inevitable impurities. The room temperature tensile strength of the alloy can reach 550-590MPa, and the elongation after fracture can reach 16.0%-19.0%; the tensile strength at 200°C can reach 440-480MPa, and the elongation after fracture can reach 17.0%-20.0%; the tensile strength at 300°C can reach 190-220MPa, and the elongation after fracture can reach 17.0%-20.0%.

[0032] The preparation method of the 2000 series aluminum alloy as described above, the preparation steps are as follows:

[0033] (1) According to the alloy composition, alloy raw materials are weighed, smelted and cast to obtain ingots, the smelting temperature is 700-750°C, and the casting temperature is 700-720°C;

[0034] (2) homogenizing the ingot obtained in step (1): first heating the ingot to 400-450° C. and keeping the temperature for 20-30 h; then heating the ingot to 480-510° C. and keeping the temperature for 20-30 h; then removing the ingot from the furnace and air cooling it to room temperature;

[0035] (3) hot extrusion or hot rolling of the ingot after homogenization treatment in step (2): the heating temperature of the aluminum alloy ingot is 380-420° C., and the heating time is 2-4 hours; the extrusion ratio during extrusion is 9-50, and the total deformation during rolling is 50%-90%;

[0036] (4) performing a two-stage solid solution treatment on the aluminum material after the hot processing in step (3): first heating to 490-500° C. and keeping the temperature for 1-2 hours; then heating to 500-510° C. and keeping the temperature for 1-2 hours; and then quenching in water;

[0037] (5) performing aging treatment on the aluminum material after the solution treatment in step (4): heating to 150-170° C. and keeping the temperature for 20-30 hours to obtain the final aluminum material.

[0038] Technical points of the present invention:

[0039] Compared with high-performance 2000 series aluminum alloys such as 2024, 2524, and 2519, the present invention adds an appropriate amount of Cr element with a slow diffusion rate, and controls the Mn / Cr ratio to 2.0-2.8, which promotes the formation of Cr-containing T phase (volume fraction of more than 3%, see Figure 1 and Figure 2) is formed, which has good stability at high temperatures and is the main reason for the significant simultaneous improvement of the room temperature and high temperature mechanical properties of the alloy.

[0040] Embodiment 1:

[0041] A high-strength and heat-resistant 2000 series aluminum alloy, characterized in that the mass percentage of each component element is as follows: Cu content is 4.3%, Mg content is 1.7%, Mn content is 0.52%, Zn content is 0.51%, Cr content is 0.21%, Zr content is 0.25%, Ti content is 0.12%, and the balance is Al and unavoidable impurities.

[0042] The preparation method of the alloy of the present invention is as follows:

[0043] (1) According to the alloy composition, alloy raw materials are weighed, smelted and cast to obtain ingots, the smelting temperature is 700-750°C, and the casting temperature is 700-720°C;

[0044] (2) performing homogenization treatment on the ingot obtained in step (1): first heating the ingot to 450° C. and keeping the temperature for 24 h; then heating the ingot to 490° C. and keeping the temperature for 24 h; then taking the ingot out of the furnace and air cooling it to room temperature;

[0045] (3) hot extrusion processing is performed on the ingot after homogenization treatment in step (2): the heating temperature of the aluminum alloy ingot is 450° C., the heating time is 2 h, and the extrusion ratio is 9;

[0046] (4) subjecting the aluminum material after hot working in step (3) to a two-stage solid solution treatment: first heating to 500° C. and keeping the temperature for 1 h; then heating to 510° C. and keeping the temperature for 1 h; and then quenching in water;

[0047] (5) Performing aging treatment on the aluminum material after the solution treatment in step (4): raising the temperature to 160° C. and keeping the temperature for 24 hours to obtain the final aluminum material.

[0048] The comprehensive properties of the alloy are: room temperature tensile strength = 577MPa, elongation after fracture = 18.0%; tensile strength at 200°C = 458MPa, elongation after fracture = 19.3%; tensile strength at 300°C = 214MPa, elongation after fracture = 18.8%.

[0049] Embodiment 2:

[0050] A high-strength and heat-resistant 2000 series aluminum alloy, characterized in that the mass percentage of each component element is as follows: Cu content is 4.9%, Mg content is 1.5%, Mn content is 0.68%, Zn content is 0.42%, Cr content is 0.32%, Zr content is 0.25%, Ti content is 0.11%, and the balance is Al and unavoidable impurities.

[0051] The preparation method of the alloy of the present invention is as follows:

[0052] (1) According to the alloy composition, alloy raw materials are weighed, smelted and cast to obtain ingots, the smelting temperature is 700-750°C, and the casting temperature is 700-720°C;

[0053] (2) homogenizing the ingot obtained in step (1): first heating the ingot to 430° C. and keeping the temperature for 24 h; then heating the ingot to 485° C. and keeping the temperature for 24 h; then removing the ingot from the furnace and air cooling it to room temperature;

[0054] (3) hot extrusion processing is performed on the ingot after homogenization treatment in step (2): the heating temperature of the aluminum alloy ingot is 420° C., the heating time is 2 h, and the extrusion ratio is 12;

[0055] (4) subjecting the aluminum material after the heat treatment in step (3) to a two-stage solid solution treatment: first heating the temperature to 495° C. and keeping the temperature for 1 h; then heating the temperature to 505° C. and keeping the temperature for 1 h; and then quenching in water;

[0056] (5) Performing aging treatment on the aluminum material after the solution treatment in step (4): raising the temperature to 165° C. and keeping the temperature for 24 hours to obtain the final aluminum material.

[0057] The comprehensive properties of the alloy are: room temperature tensile strength = 572MPa, elongation after fracture = 17.2%; tensile strength at 200°C = 459MPa, elongation after fracture = 17.3%; tensile strength at 300°C = 195MPa, elongation after fracture = 19.2%.

[0058] Embodiment 3:

[0059] A high-strength and heat-resistant 2000 series aluminum alloy, wherein the mass percentage of each component element is as follows: Cu content is 4.2%, Mg content is 1.6%, Mn content is 0.39%, Zn content is 0.38%, Cr content is 0.15%, Zr content is 0.16%, Ti content is 0.14%, and the balance is Al and unavoidable impurities.

[0060] The preparation method of the alloy of the present invention is as follows:

[0061] (1) According to the alloy composition, alloy raw materials are weighed, smelted and cast to obtain ingots, the smelting temperature is 700-750°C, and the casting temperature is 700-720°C;

[0062] (2) performing homogenization treatment on the ingot obtained in step (1): first heating the ingot to 445° C. and keeping the temperature for 24 h; then heating the ingot to 485° C. and keeping the temperature for 24 h; then taking the ingot out of the furnace and air cooling it to room temperature;

[0063] (3) hot extrusion processing is performed on the ingot after homogenization treatment in step (2): the heating temperature of the aluminum alloy ingot is 410° C., the heating time is 2 h, and the extrusion ratio is 25;

[0064] (4) performing a two-stage solid solution treatment on the aluminum material after the hot processing in step (3): first heating to 500° C. and keeping the temperature for 1 hour; then heating to 510° C. and keeping the temperature for 1 hour; and then quenching in water;

[0065] (5) Performing aging treatment on the aluminum material after the solution treatment in step (4): raising the temperature to 160° C. and keeping the temperature for 24 hours to obtain the final aluminum material.

[0066] The comprehensive properties of the alloy are: room temperature tensile strength = 573MPa, elongation after fracture = 15.8%; tensile strength at 200°C = 452MPa, elongation after fracture = 19.5%; tensile strength at 300°C = 203MPa, elongation after fracture = 19.5%.

[0067] Embodiment 4:

[0068] A high-strength and heat-resistant 2000 series aluminum alloy, characterized in that the mass percentage of each component element is as follows: Cu content is 4.8%, Mg content is 1.7%, Mn content is 0.92%, Zn content is 0.47%, Cr content is 0.38%, Zr content is 0.26%, Ti content is 0.14%, and the balance is Al and unavoidable impurities.

[0069] The preparation method of the alloy of the present invention is as follows:

[0070] (1) According to the alloy composition, alloy raw materials are weighed, smelted and cast to obtain ingots, the smelting temperature is 700-750°C, and the casting temperature is 700-720°C;

[0071] (2) performing homogenization treatment on the ingot obtained in step (1): first heating to 450° C. and keeping the temperature for 24 h; then heating to 495° C. and keeping the temperature for 24 h; then taking out of the furnace and air cooling to room temperature;

[0072] (3) hot rolling the ingot after homogenization treatment in step (2): the heating temperature of the aluminum alloy ingot is 415° C., the heating time is 2 h; the total rolling deformation is 70%;

[0073] (4) subjecting the aluminum material after hot working in step (3) to a two-stage solid solution treatment: first heating to 500° C. and keeping the temperature for 1 h; then heating to 510° C. and keeping the temperature for 1 h; and then quenching in water;

[0074] (5) Performing aging treatment on the aluminum material after the solution treatment in step (4): raising the temperature to 165° C. and keeping the temperature for 24 hours to obtain the final aluminum material.

[0075] The comprehensive properties of the alloy are: room temperature tensile strength = 563MPa, elongation after fracture = 16.8%; tensile strength at 200°C = 448MPa, elongation after fracture = 17.5%; tensile strength at 300°C = 197MPa, elongation after fracture = 19.0%.

[0076] Embodiment 5:

[0077] A high-strength and heat-resistant 2000 series aluminum alloy, characterized in that the mass percentage of each component element is as follows: Cu content is 4.3%, Mg content is 1.5%, Mn content is 0.77%, Zn content is 0.58%, Cr content is 0.33%, Zr content is 0.19%, Ti content is 0.16%, and the balance is Al and unavoidable impurities.

[0078] The preparation method of the alloy of the present invention is as follows:

[0079] (1) According to the alloy composition, alloy raw materials are weighed, smelted and cast to obtain ingots, the smelting temperature is 700-750°C, and the casting temperature is 700-720°C;

[0080] (2) homogenizing the ingot obtained in step (1): first heating the ingot to 435° C. and keeping the temperature for 24 h; then heating the ingot to 500° C. and keeping the temperature for 24 h; then removing the ingot from the furnace and air cooling it to room temperature;

[0081] (3) hot rolling the ingot after homogenization treatment in step (2): the heating temperature of the aluminum alloy ingot is 450° C., the heating time is 2 h; the total rolling deformation is 90%;

[0082] (4) subjecting the aluminum material after hot working in step (3) to a two-stage solid solution treatment: first heating to 500° C. and keeping the temperature for 1.5 h; then heating to 510° C. and keeping the temperature for 1 h; and then quenching in water;

[0083] (5) Performing aging treatment on the aluminum material after the solution treatment in step (4): raising the temperature to 170° C. and keeping the temperature for 24 hours to obtain the final aluminum material.

[0084] The comprehensive properties of the alloy are: room temperature tensile strength = 556MPa, elongation after fracture = 17.0%; tensile strength at 200°C = 445MPa, elongation after fracture = 18.2%; tensile strength at 300°C = 199MPa, elongation after fracture = 19.0%.

[0085] Embodiment 6:

[0086] A high-strength and heat-resistant 2000 series aluminum alloy, characterized in that the mass percentage of each component element is as follows: Cu content is 4.7%, Mg content is 1.7%, Mn content is 0.65%, Zn content is 0.41%, Cr content is 0.24%, Zr content is 0.19%, Ti content is 0.11%, and the balance is Al and unavoidable impurities.

[0087] The preparation method of the alloy of the present invention is as follows:

[0088] (1) According to the alloy composition, alloy raw materials are weighed, smelted and cast to obtain ingots, the smelting temperature is 700-750°C, and the casting temperature is 700-720°C;

[0089] (2) homogenizing the ingot obtained in step (1): first heating the ingot to 440° C. and keeping the temperature for 24 h; then heating the ingot to 490° C. and keeping the temperature for 24 h; then removing the ingot from the furnace and air cooling it to room temperature;

[0090] (3) hot rolling the ingot after homogenization treatment in step (2): the heating temperature of the aluminum alloy ingot is 400° C., the heating time is 2 h; the total rolling deformation is 80%;

[0091] (4) subjecting the aluminum material after hot working in step (3) to a two-stage solid solution treatment: first heating to 500° C. and keeping the temperature for 1 h; then heating to 510° C. and keeping the temperature for 1 h; and then quenching in water;

[0092] (5) Performing aging treatment on the aluminum material after the solution treatment in step (4): raising the temperature to 160° C. and keeping the temperature for 28 hours to obtain the final aluminum material.

[0093] The comprehensive properties of the alloy are: room temperature tensile strength = 561MPa, elongation after fracture = 17.7%; tensile strength at 200℃ = 448MPa, elongation after fracture = 18.1%; tensile strength at 300℃ = 191MPa, elongation after fracture = 19.5%. Figure 3 shown.

[0094] The above is a detailed introduction to a high-strength and heat-resistant 2000 series aluminum alloy, a preparation method and an application provided in the embodiments of the present application. The description of the above embodiments is only used to help understand the method and its core idea of ​​the present application; at the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

[0095] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" and "comprising" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0096] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0097] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0098] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A high-strength and heat-resistant 2000 series aluminum alloy, characterized in that: The mass percentages of the constituent elements of the high-strength and heat-resistant 2000 series aluminum alloy are: 4.0%-5.0% Cu, 1.5%-2.0% Mg, 0.30%-1.00% Mn, 0.30%-0.60% Zn, 0.10%-0.50% Cr, 0.10%-0.30% Zr, 0.10%-0.20% Ti, and the remainder is Al and unavoidable impurities.

2. The high-strength and heat-resistant 2000 series aluminum alloy according to claim 1, characterized in that: The Mn / Cr ratio in the high-strength and heat-resistant 2000 series aluminum alloy is 2.0-2.8, forming a Cr-containing T phase with a volume fraction of not less than 3%.

3. The high-strength and heat-resistant 2000 series aluminum alloy according to claim 2, characterized in that: The Cr-containing T phase has a multiple twin structure.

4. A method for preparing the high-strength and heat-resistant 2000 series aluminum alloy according to any one of claims 1 to 3, the method specifically comprising the following steps: S1) weighing each alloy raw material according to the designed ratio, melting and casting to obtain an ingot, the melting temperature is 700-750° C., and the casting temperature is 700-720° C.; S2) homogenizing the ingot obtained in S1), and then air-cooling the ingot to room temperature; S3) hot extruding or hot rolling the ingot after the homogenization treatment in S2); S4) performing a two-stage solid solution treatment on the aluminum material after the heat treatment in S3), and then quenching in water; S5) performing aging treatment on the aluminum material after the solid solution treatment in S4), the aging treatment process is as follows: heating to 150-170° C., keeping the temperature for 20-30 hours, and obtaining a high-strength and heat-resistant 2000 series aluminum alloy after cooling.

5. The method according to claim 4, characterized in that The specific process of the homogenization treatment in S2) is as follows: firstly heating to 400-450°C and keeping the temperature for 20-30h; then heating to 480-510°C and keeping the temperature for 20-30h.

6. The method according to claim 4, characterized in that The process parameters of hot extrusion in S3) are as follows: the heating temperature of the ingot is 380-420°C, the heating time is 2-4h, and the extrusion ratio is 9-50; the process parameters of hot rolling in S3) are as follows: the heating temperature of the ingot is 380-420°C, the heating time is 2-4h, and the total rolling deformation is 50%-90%.

7. The method according to claim 4, characterized in that The process of the two-stage solution treatment in S4) is as follows: firstly heating to 490-500°C and keeping the temperature for 1-2h; then heating to 500-510°C and keeping the temperature for 1-2h.

8. The method according to claim 4, characterized in that The high-strength and heat-resistant 2000 series aluminum alloy prepared by the method has a tensile strength of 550-590 MPa at room temperature and an elongation of 16.0%-19.0%; a tensile strength of 440-480 MPa at 200°C and an elongation of 17.0%-20.0%; and a tensile strength of 190-220 MPa at 300°C and an elongation of 17.0%-20.0%.

9. A high-strength and heat-resistant 2000 series aluminum alloy as claimed in any one of claims 1 to 3, which is used in the aerospace field.

Images