Ultra-high strength and very tough al-cu-li-mg-zn-mn-zr alloy plate, and preparation method therefor and use thereof

Abstract

Disclosed in the present application are an ultra-high strength and very tough Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate, and a preparation method therefor and the use thereof. The alloy plate comprises: Cu: 4.4-4.9%, Li: 1.0-1.3%, Mg: 0.3-0.6%, Zn: 0.6-1.0%, Mn: 0.3-0.7%, Zr: 0.08-0.15%, Si≤0.1%, Fe≤0.12%, Ti≤0.1%, Mg+Zn≥1.0%, and less than 0.05% of other inevitable individual impurity elements, the total amount of the impurity elements being less than 0.15%, with the balance being Al. The alloy does not contain noble metals Ag, Sc, etc., thereby effectively reducing the cost; and by matching the content of alloy elements and optimizing the density of a submicron crystal structure, the alloy has ultra-high strength and is very tough, the tensile strength of an aluminum alloy plate is greater than or equal to 650 MPa, the yield strength is greater than or equal to 615 MPa, the L-T direction fracture toughness is greater than or equal to 27 MPa·m1 / 2, and the density is less than or equal to 2.73 g / cm3, such that the alloy is suitable for aerospace equipment structural parts.

Description

Ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate and its preparation method and application

[0001] This application claims priority to Chinese patent application No. 202311457643.4, filed on November 3, 2023. This application incorporates the entire text of the aforementioned Chinese patent application. Technical Field

[0002] The present application relates to the field of alloy technology, and in particular to an ultra-high-strength and high-toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate, a preparation method thereof, and an application thereof. Background Art

[0003] Reducing the weight of aerospace vehicles is a crucial aspect of improving their performance, and the use of low-density and high-strength materials are two effective methods for achieving this. Therefore, aluminum-lithium alloys, which combine low density and high strength, have long been of great interest to materials researchers. For every 1wt.% increase in Li, the alloy density decreases by approximately 3%. At the same time, increasing the alloy's strength under certain component service load conditions can reduce the component's cross-sectional area, which also plays a positive role in reducing the component's weight. Therefore, reducing the weight of aerospace components requires further increases in strength. At the same time, aerospace equipment is placing increasingly higher demands on the toughness of materials. Improving material toughness while maintaining high strength is a current technical challenge in the field of aluminum alloys. Furthermore, the relatively high cost of aluminum-lithium alloys limits their scope of application to a certain extent, and reducing the cost of aluminum-lithium alloys is also an issue that requires comprehensive consideration.

[0004] Patent CN102021457B discloses a high-strength and toughness aluminum-lithium alloy and its preparation method, the chemical composition by weight percentage of Cu3.2-4.2%, Li0.7-1.8%, Mn0.2-0.6%, Zn0.2-0.6%, Zr0.06-0.2%, Mg0.2-0.8%, Ag0.2-0.7% and other impurity elements, the rolled plate has a tensile strength of 550MPa and an elongation of 10.4%; Patent CN101855376B discloses an Al-Cu-Li alloy product suitable for aviation applications, the chemical composition by weight percentage includes Cu3.4-5 .0, Li0.9-1.7, Mg about 0.2-0.8, Ag about 0.1-0.8, Mn about 0.1-0.9, Zn up to 1.5 and trace elements Zr, Cr, Ti, Sc, Hf, the tensile strength of the plate reaches 617MPa; Patent CN102634707B discloses an ultra-high strength aluminum-lithium alloy and heat treatment process, the alloy contains 4-4.5% Cu, 1.3-1.4% Li, 0.3-0.5% Mg, 0.2-0.4% Ag, 0.05-0.2% Zr by weight, the tensile strength of the extruded bar is not less than 630MPa; Patent CN 103370432 A discloses an aluminum-copper-lithium alloy with improved compressive strength and toughness, containing 4.2 to 4.6 weight percent Cu, 0.8 to 1.30 weight percent Li, 0.3 to 0.8 weight percent Mg, 0.05 to 0.18 weight percent Zr, 0.05 to 0.4 weight percent Ag, 0.0 to 0.5 weight percent Mn, up to 0.20 weight percent Fe+Si, less than 0.20 weight percent Zn, and at least one element selected from Cr, Sc, Hf, and Ti, and the rolled plate has a tensile yield strength of more than 640 MPa; Patent CN 110423927A discloses an ultra-high-strength aluminum-lithium alloy and its preparation method, wherein the alloy has a composition of 4.3 to 5.2 ... 0.8~1.2%, Mg0.3~0.7%, Ag0.1~0.5%, Zn0.81~1.5%, Mn0.1~0.2%, Zr 0.1~0.2%, Sc0.09~0.3%. The tensile strength of the extruded plate reaches 700MPa after solid solution, cold rolling and aging treatment.

[0005] In order to achieve ultra-high strength, some patents add precious metals Ag and Sc, which increases the cost of the alloy; some patents obtain high strength through complex processing techniques, but lack matching with toughness; some patents report ultra-high strength aluminum-lithium alloy extrusions, which are limited in width and have a relatively narrow range of applications.

[0006] Given the shortcomings of the above existing technologies, achieving ultra-high strength and toughness in large-scale plates through rolling is even more difficult. Currently, no published patents have reported achieving both ultra-high strength and high toughness simultaneously. Therefore, the current focus and challenge in the field of ultra-high-strength aluminum-lithium alloy plates is to achieve low-cost raw material control through composition design, combined with a rational processing technique to achieve a balance of ultra-high strength and high toughness to meet the requirements of large-scale components in aerospace equipment.

[0007] Summary of the Invention

[0008] To address the problems existing in the prior art, the present application provides an ultra-high-strength and high-toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate and its preparation method and application, which specifically include the following contents:

[0009] Disclosed is an ultra-high-strength and high-toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate. The alloy plate comprises the following components and weight percentages: Cu 4.4-4.9%, Li 1.0-1.3%, Mg 0.3-0.6%, Zn 0.6-1.0%, Mn 0.3-0.7%, Zr 0.08-0.15%, Si≤0.1%, Fe≤0.12%, and Ti≤0.1%, wherein Mg+Zn≥1.0%, the content of other unavoidable individual impurity elements is less than 0.05%, and the total amount of impurity elements is less than 0.15%, and the remainder is Al.

[0010] Preferably, the components and weight percentages of the alloy plate include: Cu 4.4-4.8%, Li 1.1-1.3%, Mg 0.4-0.5%, Zn 0.7-1.0%, Mn 0.4-0.7%, Zr 0.09-0.13%, Si≤0.1%, Fe≤0.1%, Ti≤0.1%, wherein Mg+Zn≥1.2%, other unavoidable single impurity elements are less than 0.05% and the total amount of impurity elements is less than 0.15%, and the rest is Al.

[0011] Preferably, the Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate has a tensile strength of ≥650 MPa, a yield strength of ≥615 MPa, and a LT fracture toughness of ≥27 MPa·m 1 / 2 , density ≤ 2.73g / cm 3 .

[0012] A method for preparing the ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate mentioned above in this application comprises the following steps:

[0013] (1) Homogenization treatment: first, heat the alloy ingot with the components to 370-390°C; then heat it to 420-440°C at a heating rate of 5-8°C / h, then heat it to 500-510°C, and keep it at that temperature for 6-12h; then heat it to 545-550°C at a heating rate of 5-10°C / h, and keep it at that temperature for 6-12h; finally, cool the treated ingot to room temperature by strong wind;

[0014] (2) rolling: rolling the ingot treated in step (1) to obtain a plate;

[0015] (3) Solution treatment: The plate obtained in step (2) is subjected to solution treatment. The specific solution treatment process is to first heat the plate to 380-440°C, keep it warm for 2-4 hours, then heat it to 530-540°C, and keep it warm for 1-2 hours;

[0016] (4) Pre-stretching: pre-stretching the plate after treatment in step (3);

[0017] (5) Artificial aging: The plate treated in step (4) is artificially aged to obtain an ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate.

[0018] Preferably, the process conditions for rolling in step (2) are: the total rolling deformation is not less than 70%, and the thickness of the rolled plate is 10-20 mm.

[0019] Preferably, after the solution treatment and heat preservation in step (3) is completed, the plate is cooled to below 100° C. within 10 seconds.

[0020] Preferably, the stretching amount of the pre-stretching deformation in step (4) is 3.0-4.0%.

[0021] Preferably, the temperature of artificial aging in step (5) is 145-155° C., and the holding time of artificial aging is 24-36 hours.

[0022] An application of the ultra-high-strength and high-toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate described above in an aerospace vehicle.

[0023] Beneficial effects of this application:

[0024] (1) The ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr aluminum alloy plate disclosed in this application comprises the following components: Cu 4.4-4.9%, Li 1.0-1.3%, Mg 0.3-0.6%, Zn 0.6-1.0%, Mn 0.3-0.7%, Zr 0.08-0.15%, Si≤0.1%, Fe≤0.12%, Ti≤0.1%, wherein Mg+Zn≥1.0%, the content of other unavoidable single impurity elements is less than 0.05% and the total amount of impurity elements is less than 0.15%, and the rest is Al. The alloy of this application does not contain precious metal Ag and expensive rare earth element Sc, which effectively reduces material costs; and optimizes the addition amount of Cu, Li, and Zn elements, and limits Mg+Zn ≥ 1.0%. By matching the content of alloying elements, the proportion of strengthening phases of different properties is optimized, making the alloy have the comprehensive performance characteristics of ultra-high strength and high toughness. The tensile strength of the aluminum alloy plate is ≥ 650MPa, the yield strength is ≥ 615MPa, and the LT fracture toughness is ≥ 27MPa·m 1 / 2 , density ≤ 2.73g / cm 3 .

[0025] (2) The method for preparing ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plates disclosed in this application adopts a new homogenization process. The homogenization treatment is carried out at a reasonable temperature, which significantly improves the efficiency of the coarse phase re-dissolution, can eliminate the coarse phase of the ingot to the greatest extent, and allows the alloy elements to fully exert their strengthening effect, thereby improving the plastic deformation ability and aging strengthening ability of the ingot. The plates prepared by this method achieve a good match between ultra-high strength and high toughness, with a tensile strength of more than 650MPa and a LT fracture toughness of 27MPa·m 1 / 2 , exceeding the strength and fracture toughness of conventional ultra-high-strength 7055 aluminum alloy, and the density is 4.5% lower than that of 7055 aluminum alloy.

[0026] (3) The preparation method of the ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate disclosed in this application adopts a gradient heating method to control the grain morphology and the number of submicron-scale crystal structures, which is more conducive to improving the strength and fracture toughness of the alloy and achieving a combination of ultra-high strength and high toughness.

[0027] The Al-Cu-Li-Mg-Zn-Mn-Zr aluminum alloy disclosed in the present application is suitable for large structural parts of aerospace vehicles, such as aircraft wing panels, spacecraft fuel tanks, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is the microstructure of the alloy A ingot in Example 1 of the present application;

[0029] FIG2 is a homogenized microstructure of the B alloy ingot in Example 1 of the present application;

[0030] FIG3 is the metallographic microstructure of the C alloy plate in Example 2 of the present application;

[0031] FIG4 is the metallographic microstructure of the D alloy plate in Example 2 of the present application;

[0032] FIG5 is the grain structure of the E alloy plate in Example 3 of the present application;

[0033] FIG6 is the aging precipitation phase structure of the F alloy plate in Example 3 of the present application;

[0034] FIG7 is the grain structure of the G alloy plate in Comparative Example 1 of the present application;

[0035] FIG8 is the aging precipitation phase structure of the H alloy plate in Comparative Example 2 of the present application;

[0036] FIG9 is a tensile curve of alloy A in Example 1 of the present application and alloy G in Comparative Example 1. DETAILED DESCRIPTION

[0037] The present application is described in detail below with reference to Figures 1-9 and specific embodiments. The embodiments shown below do not limit the invention as described in the claims. In addition, the entire contents of the structures shown in the following embodiments are not limited to those necessary for the solution of the invention described in the claims.

[0038] Disclosed is an ultra-high-strength and high-toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate. The alloy comprises the following components and weight percentages: Cu 4.4-4.9%, Li 1.0-1.3%, Mg 0.3-0.6%, Zn 0.6-1.0%, Mn 0.3-0.7%, Zr 0.08-0.15%, Si ≤ 0.1%, Fe ≤ 0.12%, Ti ≤ 0.1%, wherein Mg + Zn ≥ 1.0%, the content of other unavoidable individual impurity elements is less than 0.05% and the total amount of impurity elements is less than 0.15%, and the remainder is Al. Specifically, the Cu content in the alloy can be 4.5%, 4.6%, 4.7%, 4.8%, 4.85%, etc.; the Li content in the alloy can be 1.05%, 1.1%, 1.15%, 1.2%, 1.25%, etc.; the Mg content in the alloy can be 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, etc.; the Zn content in the alloy can be 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, etc.; the Mn content in the alloy can be 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0. 65%, etc.; the Zr content in the alloy can be 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, etc.; the Si content in the alloy can be 0, 0.01%, 0.02%, 0.05%, 0.08%, etc.; the Fe content in the alloy can be 0, 0.02%, 0.05%, 0.08%, 0.10%, etc.; the Ti content in the alloy can be 0, 0.02%, 0.04%, 0.06%, 0.08%, etc.; Mg+Zn can be 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, 2.2%, etc.

[0039] The tensile strength of Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate is ≥650MPa, the yield strength is ≥615MPa, and the LT fracture toughness is ≥27MPa·m 1 / 2 , density ≤ 2.73g / cm 3 .

[0040] The above-mentioned ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate can be used to prepare aerospace vehicles.

[0041] A method for preparing the above-mentioned ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate comprises the following steps:

[0042] (1) Homogenization treatment: first, heat the alloy ingot having the above composition to 370-390°C (e.g., 375°C, 380°C, 385°C, etc.); then heat it to 420-440°C (e.g., 425°C, 430°C, 435°C, etc.) at a heating rate of 5-8°C / h (e.g., 5.5°C / h, 6°C / h, 6.5°C / h, 7°C / h, 7.5°C / h, etc.), and then continue heating to 500-510°C (e.g., 502°C, 504°C, 506°C, 508°C, etc.). The temperature is raised to 510°C, 514°C, 516°C, 518°C, etc.), and kept warm for 6-12h (e.g., 7h, 8h, 9h, 10h, 11h, etc.); then the temperature is raised to 545-550°C (e.g., 546°C, 547°C, 548°C, 549°C, etc.) at a heating rate of 5-10°C / h (e.g., 6°C / h, 7°C / h, 8°C / h, 9°C / h, etc.), and kept warm for 6-12h (e.g., 7h, 8h, 9h, 10h, 11h, etc.); finally, the treated ingot is cooled to room temperature by strong wind;

[0043] (2) rolling: rolling the ingot after treatment in step (1), wherein the total deformation of the rolling is not less than 70% (e.g., 75%, 80%, 85%, 90%, etc.), and the thickness of the rolled plate is 10-20 mm (e.g., 12 mm, 14 mm, 16 mm, 18 mm, etc.);

[0044] (3) Solution treatment: The plate obtained after the treatment in step (2) is subjected to solution treatment, the plate is heated to 380-440°C (for example, 390°C, 400°C, 410°C, 420°C, 430°C, etc.), kept warm for 2-4 hours (for example, 2.5 hours, 3 hours, 3.5 hours, etc.), then heated to 530-540°C (for example, 535°C, etc.), kept warm for 1-2 hours (for example, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, etc.);

[0045] (4) Pre-stretching: The plate treated in step (3) is pre-stretched and deformed, and the stretching amount of the pre-stretching deformation is 3.0-4.0% (e.g., 3.3%, 3.6%, 3.9%, etc.);

[0046] (5) Artificial aging: The plate treated in step (4) is artificially aged at a temperature of 145-155°C (e.g., 146°C, 148°C, 150°C, 152°C, 154°C, etc.) for a holding time of 24-36h (e.g., 26h, 28h, 30h, 32h, 34h, etc.) to obtain an ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate.

[0047] This application follows the means of low-cost alloy design, reasonable ratio of alloy elements, and optimization of processing technology to achieve the comprehensive performance of ultra-high strength and high toughness. Four innovative measures are adopted: (1) No rare metal elements are added to the alloy composition, which reduces the alloy cost; (2) The addition amount of Cu, Li, and Zn elements is designed. By adjusting the content of alloy elements and optimizing the proportion of different strengthening phases, the alloy has the comprehensive performance of ultra-high strength and high toughness; (3) The use of new homogenization treatment and other processing methods significantly improves the efficiency of coarse phase re-dissolution, allowing the alloy elements to fully play a strengthening role through aging precipitation; (4) The use of pre-solution treatment methods reduces the degree of recrystallization to a certain extent, while retaining the high-density submicron-scale microstructure, which helps to improve strength and toughness.

[0048] The preferred embodiments of the present invention are described in detail below. The following embodiments and comparative examples are only used to illustrate the present invention, but they are not intended to limit the scope of protection of the present invention.

[0049] Example 1

[0050] Alloy A's components and weight percentages include: Cu 4.9%, Li 1.0%, Mg 0.3%, Zn 1.0%, Mn 0.3%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder being Al and unavoidable impurity elements;

[0051] The composition and weight percentage of alloy B include: Cu 4.9%, Li 1.3%, Mg 0.3%, Zn 0.8%, Mn 0.3%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the balance is Al and unavoidable impurity elements;

[0052] The alloy A and alloy B ingots were homogenized, and the ingots were heated to 370°C, then heated to 420°C at a heating rate of 8°C / h, and then heated to 510°C and kept at this temperature for 12 hours; then heated to 545°C at a heating rate of 10°C / h, and kept at this temperature for 12 hours, and then the ingots were cooled to room temperature by strong wind;

[0053] The alloys A and B were homogenized and then cast into ingots, wherein the alloy A was rolled into plates with a thickness of 10 mm and a rolling deformation of 87.5%; the alloy B was rolled into plates with a thickness of 20 mm and a rolling deformation of 75%.

[0054] The above-mentioned alloy A and alloy B plates were solution treated, and the temperature of alloy A was first raised to 380℃, kept warm for 4 hours, and then raised to 540℃, kept warm for 1 hour; the temperature of alloy B was first raised to 440℃, kept warm for 2 hours, and then raised to 540℃, kept warm for 2 hours; after the solution treatment and holding of alloy A and alloy B were completed, they were cooled to below 100℃ within 10 seconds.

[0055] The above-mentioned A alloy and B alloy plates were pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a heat preservation time of 30 hours.

[0056] Example 2

[0057] The C alloy composition and weight percentages include: Cu 4.4%, Li 1.0%, Mg 0.6%, Zn 0.6%, Mn 0.7%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0058] The composition and weight percentage of the D alloy include: Cu 4.4%, Li 1.3%, Mg 0.6%, Zn 0.6%, Mn 0.7%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the rest are Al and unavoidable impurity elements;

[0059] The C alloy and D alloy ingots were homogenized, and the ingots were heated to 390°C, then heated to 440°C at a heating rate of 5°C / h, and then heated to 500°C and kept at this temperature for 6 hours; then heated to 550°C at a heating rate of 5°C / h, and kept at this temperature for 6 hours, and then the ingots were cooled to room temperature by strong wind;

[0060] The C alloy and the D alloy were homogenized and then cast into ingots, wherein the C alloy was rolled to obtain a plate with a thickness of 10 mm and a rolling deformation of 87.5%; the D alloy was rolled to obtain a plate with a thickness of 20 mm and a rolling deformation of 75%.

[0061] The above-mentioned C alloy and D alloy plates were solution treated, and the C alloy was first heated to 380°C and kept warm for 4 hours, and then heated to 530°C and kept warm for 2 hours; the D alloy was first heated to 440°C and kept warm for 2 hours, and then heated to 530°C and kept warm for 2 hours; after the solution treatment and holding of the C and D alloys were completed, they were cooled to below 100°C within 10 seconds.

[0062] The A alloy and B alloy plates were pre-stretched and artificially aged, with a pre-stretching amount of 4.0%, an aging temperature of 150° C., and a holding temperature of 30 h.

[0063] Example 3

[0064] The E alloy composition and weight percentages include: Cu 4.6%, Li 1.0%, Mg 0.4%, Zn 1.0%, Mn 0.5%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0065] The F alloy composition and weight percentages include: Cu 4.6%, Li 1.3%, Mg 0.4%, Zn 0.6%, Mn 0.5%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0066] The E alloy and F alloy ingots were homogenized, and the ingots were heated to 380°C, then heated to 430°C at a heating rate of 7°C / h, and then heated to 505°C and kept at this temperature for 10 hours; then heated to 550°C at a heating rate of 8°C / h, and kept at this temperature for 10 hours, and then the ingots were cooled to room temperature by strong wind;

[0067] The E alloy and F alloy were homogenized and then cast into ingots, and the plates were 16 mm thick and 80% deformed.

[0068] The E alloy and F alloy plates were solution treated by first heating to 410°C and holding for 3 hours, then heating to 535°C and holding for 1 hour; after the solution treatment and holding, they were cooled to below 100°C within 10 seconds.

[0069] The above-mentioned E alloy and F alloy plates were pre-stretched and artificially aged. The pre-stretching amount of the E alloy plate was 4.0%, the aging temperature was 145°C, and the insulation time was 36 hours; the pre-stretching amount of the F alloy plate was 3.0%, the aging temperature was 155°C, and the insulation time was 24 hours.

[0070] Example 4

[0071] The A1 alloy composition and weight percentages include: Cu 4.9%, Li 1.0%, Mg 0.3%, Zn 1.0%, Mn 0.3%, Zr 0.08%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0072] The B1 alloy composition and weight percentages include: Cu 4.9%, Li 1.3%, Mg 0.3%, Zn 0.8%, Mn 0.3%, Zr 0.15%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0073] The A1 alloy and B1 alloy ingots were homogenized, and the ingots were heated to 370°C, then heated to 420°C at a heating rate of 8°C / h, and then heated to 510°C and kept at this temperature for 12 hours; then heated to 545°C at a heating rate of 10°C / h, and kept at this temperature for 12 hours, and then the ingots were cooled to room temperature by strong wind;

[0074] The A1 alloy and the B1 alloy were homogenized and then cast into ingots, wherein the A1 alloy was rolled into a plate having a thickness of 10 mm and a rolling deformation of 87.5%; the B1 alloy was rolled into a plate having a thickness of 20 mm and a rolling deformation of 75%.

[0075] The above-mentioned A1 alloy and B1 alloy plates were solution treated, and the A1 alloy was first heated to 380°C and kept warm for 4 hours, and then heated to 540°C and kept warm for 1 hour; the B1 alloy was first heated to 440°C and kept warm for 2 hours, and then heated to 540°C and kept warm for 2 hours; after the solution treatment and holding of the A1 alloy and the B1 alloy were completed, they were cooled to below 100°C within 10 seconds.

[0076] The A1 alloy and B1 alloy plates were pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a holding time of 30 h.

[0077] Example 5

[0078] The A2 alloy composition and weight percentages include: Cu 4.9%, Li 1.0%, Mg 0.5%, Zn 1.0%, Mn 0.4%, Zr 0.09%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0079] The B2 alloy composition and weight percentages include: Cu 4.8%, Li 1.3%, Mg 0.3%, Zn 0.7%, Mn 0.3%, Zr 0.13%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0080] The A2 alloy and B2 alloy ingots were homogenized, and the ingots were heated to 370°C, then heated to 420°C at a heating rate of 8°C / h, and then heated to 510°C and kept at this temperature for 12 hours; then heated to 545°C at a heating rate of 10°C / h, and kept at this temperature for 12 hours, and then the ingots were cooled to room temperature by strong wind;

[0081] The A2 alloy and the B2 alloy were homogenized and then cast into ingots, wherein the A2 alloy was rolled into a plate with a thickness of 10 mm and a rolling deformation of 87.5%; the B2 alloy was rolled into a plate with a thickness of 20 mm and a rolling deformation of 75%.

[0082] The above-mentioned A2 alloy and B2 alloy plates were solution treated, and the A2 alloy was first heated to 380°C and kept warm for 4 hours, and then heated to 540°C and kept warm for 1 hour; the B2 alloy was first heated to 440°C and kept warm for 2 hours, and then heated to 540°C and kept warm for 2 hours; after the solution treatment and holding of the A2 alloy and the B2 alloy were completed, they were cooled to below 100°C within 10 seconds.

[0083] The A2 alloy and B2 alloy plates were pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a heat preservation time of 30 h.

[0084] Comparative Example 1

[0085] The G alloy composition and weight percentages include: Cu 5.2%, Li 0.8%, Mg 0.4%, Zn 0.8%, Mn 0.5%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0086] The G alloy ingot was homogenized by first heating the ingot to 380°C, then heating it to 430°C at a heating rate of 5°C / h, then heating it to 500°C and holding it for 12 hours; then heating it to 545°C at a heating rate of 5°C / h and holding it for 6 hours, and then cooling the ingot to room temperature with strong wind;

[0087] The G alloy ingot after homogenization treatment was rolled to obtain a plate with a thickness of 10 mm and a rolling deformation of 87.5%;

[0088] After the G alloy is rolled, the plate is subjected to a solution treatment, first heated to 440°C and kept at this temperature for 2 hours, then heated to 540°C and kept at this temperature for 1 hour; after the solution treatment and holding, the plate is cooled to below 100°C within 10 seconds;

[0089] The G alloy plate was pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a heat preservation time of 30 h.

[0090] Comparative Example 2

[0091] The H alloy composition and weight percentages include: Cu 4.0%, Li 1.6%, Mg 0.4%, Zn 0.8%, Mn 0.5%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0092] The H alloy ingot was homogenized, and the ingot was heated to 510°C at a heating rate of 150°C / min and kept at this temperature for 6 hours; then the ingot was heated to 550°C at a heating rate of 5°C / h and kept at this temperature for 12 hours, and then the ingot was cooled to room temperature by strong wind;

[0093] The H alloy ingot after homogenization treatment was rolled to obtain a plate with a thickness of 10 mm and a rolling deformation of 87.5%;

[0094] The H alloy plate was subjected to solution treatment by first heating to 380°C and holding for 4 hours, then heating to 540°C and holding for 1 hour; after the solution treatment and holding, the plate was cooled to below 100°C within 10 seconds;

[0095] The H alloy plate was pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a heat preservation time of 30 h.

[0096] Comparative Example 3

[0097] The K alloy composition and weight percentages include: Cu 4.6%, Li 1.3%, Mg 0.4%, Zn 1.2%, Mn 0.5%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0098] The K alloy ingot was homogenized, and the ingot was heated to 380°C, then heated to 430°C at a heating rate of 5°C / h, and then heated to 530°C, kept at this temperature for 12 hours, and then the ingot was cooled to room temperature by strong wind;

[0099] The K alloy ingot after homogenization treatment was rolled to obtain a plate with a thickness of 20 mm and a rolling deformation of 75%;

[0100] After the K alloy is rolled, the plate is subjected to solution treatment, heated to 530°C, kept at this temperature for 2 hours, and then cooled to below 100°C within 10 seconds after the solution treatment.

[0101] The K alloy plate was pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a heat preservation time of 30 h.

[0102] Comparative Example 4

[0103] The A3 alloy composition and weight percentages include: Cu 4.9%, Li 1.0%, Mg 0.3%, Zn 1.0%, Mn 0.3%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0104] The A3 alloy ingot was homogenized, and the ingot was heated to 350°C, then heated to 400°C at a heating rate of 3°C / h, and then heated to 480°C and kept at that temperature for 5 hours; then heated to 520°C at a heating rate of 3°C / h, and kept at that temperature for 5 hours, and then the ingot was cooled to room temperature by strong wind;

[0105] The A3 alloy was homogenized and then cast into an ingot, and the A3 alloy was rolled to obtain a plate with a thickness of 10 mm and a rolling deformation of 87.5%;

[0106] The above-mentioned A3 alloy plate was subjected to solid solution treatment, and the A3 alloy was first heated to 380°C and kept warm for 4 hours, and then heated to 540°C and kept warm for 1 hour; after the solid solution and heat preservation of the A3 alloy was completed, it was cooled to below 100°C within 10 seconds.

[0107] The A3 alloy plate was pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a heat preservation time of 30 h.

[0108] Comparative Example 5

[0109] The A4 alloy composition and weight percentages include: Cu 4.9%, Li 1.0%, Mg 0.3%, Zn 1.0%, Mn 0.3%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0110] The A4 alloy ingot was homogenized, and the ingot was heated to 400°C, then heated to 450°C at a heating rate of 12°C / h, and then heated to 520°C and kept at this temperature for 14 hours; then heated to 560°C at a heating rate of 12°C / h, and kept at this temperature for 14 hours, and then the ingot was cooled to room temperature by strong wind;

[0111] The A4 alloy was homogenized and then cast into an ingot, and the A4 alloy was rolled to obtain a plate with a thickness of 10 mm and a rolling deformation of 87.5%;

[0112] The above-mentioned A4 alloy plate was subjected to solid solution treatment, and the A4 alloy was first heated to 380°C and kept warm for 4 hours, and then heated to 540°C and kept warm for 1 hour; after the solid solution and heat preservation of the A4 alloy was completed, it was cooled to below 100°C within 10 seconds.

[0113] The A4 alloy plate was pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a heat preservation time of 30 h.

[0114] Comparative Example 6

[0115] The A5 alloy composition and weight percentages include: Cu 4.9%, Li 1.0%, Mg 0.3%, Zn 1.0%, Mn 0.3%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0116] The A5 alloy ingot was homogenized, and the ingot was heated to 370°C, then heated to 420°C at a heating rate of 8°C / h, and then heated to 510°C and kept at this temperature for 12 hours; then heated to 545°C at a heating rate of 10°C / h, and kept at this temperature for 12 hours, and then the ingot was cooled to room temperature by strong wind;

[0117] The A5 alloy was homogenized and then cast into an ingot, and the A5 alloy was rolled to obtain a plate with a thickness of 10 mm and a rolling deformation of 87.5%;

[0118] The above-mentioned A5 alloy plate was subjected to solid solution treatment, and the A5 alloy was first heated to 350°C and kept warm for 1 hour, and then heated to 500°C and kept warm for 0.5 hour; after the solid solution and heat preservation of the A5 alloy was completed, it was cooled to below 100°C within 10 seconds.

[0119] The A5 alloy plate was pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a heat preservation time of 30 h.

[0120] Comparative Example 7

[0121] The A6 alloy composition and weight percentages include: Cu 4.9%, Li 1.0%, Mg 0.3%, Zn 1.0%, Mn 0.3%, Zr 0.12%, Si 0.08%, Fe 0.1%, Ti 0.05%, and the remainder is Al and unavoidable impurity elements;

[0122] The A6 alloy ingot was homogenized, and the ingot was heated to 370°C, then heated to 420°C at a heating rate of 8°C / h, and then heated to 510°C and kept at this temperature for 12 hours; then heated to 545°C at a heating rate of 10°C / h, and kept at this temperature for 12 hours, and then the ingot was cooled to room temperature by strong wind;

[0123] The A6 alloy was homogenized and then cast into an ingot, and the A6 alloy was rolled to obtain a plate with a thickness of 10 mm and a rolling deformation of 87.5%.

[0124] The above-mentioned A6 alloy plate was subjected to solid solution treatment, and the A6 alloy was first heated to 460°C and kept warm for 5 hours, and then heated to 560°C and kept warm for 4 hours; after the solid solution and heat preservation of the A6 alloy was completed, it was cooled to below 100°C within 10 seconds.

[0125] The A6 alloy plate was pre-stretched and artificially aged, with a pre-stretching amount of 3.5%, an aging temperature of 150° C., and a heat preservation time of 30 h.

[0126] Figure 1 is the metallographic microstructure of the alloy A ingot in Example 1, showing fine as-cast grains; Figure 2 is the metallographic microstructure of the alloy B ingot after homogenization in Example 1, with an average grain size of 180 μm; Figures 3 and 4 are the metallographic microstructures of the alloy C and alloy D plates in Example 2, respectively, showing the mixed microstructure characteristics of deformed grains and partially recrystallized grains; Figure 5 is the grain structure of the alloy E plate in Example 3, indicating a low degree of recrystallization in the plate formed by the deformation process; Figure 6 is the aging precipitation phase structure of the alloy F plate in Example 3, showing a high density of T1 strengthening phase and submicron-scale crystal structure retained in the plate; Figure 7 is the grain structure of the alloy G plate in Comparative Example 1, showing a high degree of recrystallization in the plate formed by the deformation process; Figure 8 is the aging precipitation phase structure of the alloy H plate in Comparative Example 2, whose strengthening phase density is lower than that of the alloy F in Example 3; and Figure 9 is the tensile curves of the alloy A in Example 1 and the alloy G in Comparative Example 1.

[0127] Table 1 is a comparison of the comprehensive performance data of the above examples and comparative examples of the present application. The tensile strength of the plates in the examples reached more than 650 MPa, and the fracture toughness reached 27 MPa·m 1 / 2 Above, density is 2.7-2.73g / cm 3 The good combination of ultra-high strength and high fracture toughness is achieved, and the material has low density. Comparative Examples 1-7 do not achieve the ideal combination of ultra-high strength and fracture toughness due to improper matching of alloy composition and process. The typical tensile strength of conventional ultra-high strength 7055-T77 alloy plate is 630MPa and the fracture toughness is 26MPa·m 1 / 2 , the regular density is 2.85g / cm 3 In comparison, the Al-Cu-Li-Mg-Zn-Mn-Zr aluminum alloy plate of the present application has the performance characteristics of ultra-high strength and toughness, low density and relatively low cost.

[0128] Table 1 Properties of the Example and Comparative Example Plates

[0129] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate, characterized in that: The components and weight percentages of the alloy plate include: Cu 4.4-4.9%, Li 1.0-1.3%, Mg 0.3-0.6%, Zn 0.6-1.0%, Mn 0.3-0.7%, Zr 0.08-0.15%, Si≤0.1%, Fe≤0.12%, Ti≤0.1%, wherein Mg+Zn≥1.0%, the content of other inevitable single impurity elements is less than 0.05% and the total amount of impurity elements is less than 0.15%, and the rest is Al.

2. The ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate according to claim 1, characterized in that: The components and weight percentages of the alloy plate include: Cu 4.4-4.8%, Li 1.1-1.3%, Mg 0.4-0.5%, Zn 0.7-1.0%, Mn 0.4-0.7%, Zr 0.09-0.13%, Si≤0.1%, Fe≤0.1%, Ti≤0.1%, wherein Mg+Zn≥1.2%, other inevitable single impurity elements are less than 0.05% and the total amount of impurity elements is less than 0.15%, and the rest is Al.

3. The ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate according to claim 1, characterized in that: The Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate has a tensile strength of ≥650MPa, a yield strength of ≥615MPa, and a LT fracture toughness of ≥27MPa·m 1 / 2 , density ≤2.73g / cm 3 .

4. A method for preparing the ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy sheet according to any one of claims 1 to 3, characterized in that: The following steps are involved: Homogenization treatment: firstly, heating the alloy ingot with the composition to 370-390°C; then heating to 420-440°C at a heating rate of 5-8°C / h, then heating to 500-510°C, and keeping the temperature for 6-12h; then heating to 545-550°C at a heating rate of 5-10°C / h, and keeping the temperature for 6-12h; finally, cooling the treated ingot to room temperature by strong wind; Rolling: rolling the ingot treated in step (1) to obtain a plate; Solution treatment: The plate obtained in step (2) is subjected to solution treatment, wherein the process of the solution treatment is as follows: firstly, the plate is heated to 380-440°C, kept at this temperature for 2-4 hours, then heated to 530-540°C, kept at this temperature for 1-2 hours; Pre-stretching: pre-stretching and deforming the plate after being processed in step (3); Artificial aging: The plate treated in step (4) is artificially aged to obtain an ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate.

5. The method for preparing an ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate according to claim 4, characterized in that: The rolling process conditions in step (2) are: the total rolling deformation is not less than 70%, and the thickness of the rolled plate is 10-20 mm.

6. The method for preparing an ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy sheet according to claim 4, characterized in that: After the solution treatment in step (3) is completed, the plate is cooled to below 100° C. within 10 seconds.

7. The method for preparing an ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate according to claim 4, characterized in that: The stretching amount of the pre-stretching deformation in step (4) is 3.0-4.0%.

8. The method for preparing an ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate according to claim 4, characterized in that: The temperature of artificial aging in step (5) is 145-155° C., and the holding time of artificial aging is 24-36 hours.

9. Use of the ultra-high strength and high toughness Al-Cu-Li-Mg-Zn-Mn-Zr alloy plate according to any one of claims 1 to 3 in aerospace vehicles.

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