Low-cost heat-resistant Al-Cu-Mg-Ag alloy and preparation and application thereof

Abstract

The invention discloses a low-cost heat-resistant Al-Cu-Mg-Ag alloy as well as a preparation method and application thereof. The heat-resistant Al-Cu-Mg-Ag alloy is prepared from the following components in percentage by mass: 4.00 percent to 4.50 percent of Cu, 0.10 percent to 0.30 percent of Mg, 0.10 percent to 0.20 percent of Ag, 0.10 percent to 0.30 percent of Mn, 0.05 percent to 0.15 percent of Zr, 0.05 percent to 0.15 percent of Ti, 0.05 percent to 0.20 percent of Si and the balance of Al and inevitable impurities. According to the alloy, the contents of Cu, Mg, Ag and Mn are properly reduced, trace alloy elements are compositely added, reasonable matching of the components is achieved, after solid solution and aging treatment, only a small amount of micron-sized second phases are left in an alloy matrix, multi-layer and multi-scale dispersion strengthening phases and precipitation strengthening phases are formed at the same time, the cost is reduced, and meanwhile the mechanical property of the alloy is improved. And good balance between strong plasticity and heat resistance is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and particularly provides a low-cost heat-resistant Al-Cu-Mg-Ag alloy and its preparation and application. Background Art

[0002] The Al-Cu-Mg-Ag quaternary alloy developed on the basis of the Al-Cu-Mg ternary alloy system promotes the preferential precipitation of the Ω phase (chemical formula: Al2Cu) on the matrix {111} Al crystal plane by adding Ag element. This precipitated phase has unique core-shell nanostructure characteristics, endowing the alloy with excellent anti-aging softening ability and high-temperature mechanical properties within the service temperature range of 150 °C. Typical Al-Cu-Mg-Ag alloys include 2139, 2040, 2055, and 2195, etc., and have been successfully applied in the fields of aircraft fuselage structural parts, landing gear hubs, and skin material manufacturing. [Ling K, Mo W F, Deng P, et al. Hot deformation behavior and dynamic softening mechanisms of hot-extruded Al-Cu-Mg-Ag-Mn-Zr-Ti alloy [J]. Materials Today Communications, 2023, 34: 105300.]. However, with the development of aircraft towards ultra-high speed, lightweight, and low-cost directions, more stringent requirements are put forward for heat-resistant aluminum alloys: while maintaining long-term service stability above 200 °C, a significant reduction in the cost of the material system is achieved. Existing research shows that the Ω phase in the Al-Cu-Mg-Ag alloy is prone to coarsening at 200 °C, resulting in a sharp drop in strength, and the high price of Ag element increases the material cost by 1 to 4 times. These dual bottlenecks of heat resistance and cost-effectiveness seriously hinder the application of the alloy in the main load-bearing components of new-generation equipment. Developing a new type of aluminum alloy with heat resistance at the 200 °C level, high strength-plasticity matching, and low cost has become an urgent need in the current high-end aviation material field.

[0003] The current research and development of Al-Cu-Mg-Ag alloys faces three main problems: (1) Although increasing the content of main alloying elements such as Cu, Mg, and Ag can effectively increase the volume fraction of precipitates and thus improve the strength of the material, the introduction of excessive elements will increase the content of primary coarse secondary phases, reduce the nucleation sites of precipitates, and lead to the coarsening of nano-precipitates, resulting in a decrease in the comprehensive properties of the alloy and a significant increase in material cost [Song Yanfang, Pan Qinglin, Cao Sufang, et al. Effect of Ag content on the microstructure and properties of Al-Cu-Mg alloys [J]. Journal of Aeronautical Materials, 2013, 33(01): 7-13.]; (2) Although introducing elements such as Ti, Sc, and Zr to form dispersed phases can improve heat resistance, their low solubility in the aluminum matrix (generally less than 0.2 wt.%) limits their strengthening effect [Zhu Baohong, Xiong Baiqing, Zhang Yong'an, et al. Effect of heat treatment process on the properties of high-purity Al-Cu-Mg-Ag alloys with trace Mn and Zr [J]. Rare Metal Materials and Engineering, 2010, 39(01): 144-148.]. (3) The main strengthening phase, the Ω phase, is prone to coarsening at 200 °C, resulting in a sharp drop in the strength of the alloy and making it difficult to meet the application requirements. Introducing Si elements can form nano-scale (<10 nm) disordered L 12 phases (AlMgSiCu phases) with Cu and Mg. This phase can not only improve the room-temperature strength of the alloy but also serve as a heterogeneous nucleation site for the θ' phase (Al2Cu phase), inhibiting the high-temperature coarsening of the θ' phase through the pinning effect, so that the alloy still maintains a high strength after long-term thermal exposure at 200 °C. However, the formation of this phase is extremely sensitive to the content ratio of Cu, Mg, and Si, and the complex interaction of multiple components in the Al-Cu-Mg-Ag system makes it difficult to achieve effective microstructure control and property improvement by traditional trial-and-error methods. [Lu Q, Wang J C, Li H C, et al. Synergy of multiple precipitate / matrix interface structures for a heatresistant high-strength Al alloy [J]. Nature communications, 2023, 14: 2959.].

[0004] Therefore, the core challenge in optimizing the comprehensive properties of current Al-Cu-Mg-Ag alloys lies in: how to achieve the triple regulation goals of "microstructure - heat resistance - cost" through multi-component collaborative design. Specifically, while reducing the micron-scale coarse phases caused by solidification segregation, it is necessary to construct both high-volume-fraction nano-precipitates and high-thermal-stability L 12Composite strengthening systems of phases. However, there are complex thermodynamic and kinetic coupling effects between the main elements of Cu, Mg, and Ag and the microalloying elements such as Si, Sc, Zr, and Ti in this system, resulting in problems such as competitive growth of precipitation phases and inhibition of elemental interdiffusion. Limited by the non-linear correlation characteristics of the multi-dimensional composition-process parameter space, the traditional trial-and-error method is difficult to systematically analyze the multi-phase cooperative precipitation mechanism, seriously restricting the directional design of high-performance heat-resistant aluminum alloys. Summary of the Invention

[0005] The present invention discloses a low-cost heat-resistant Al-Cu-Mg-Ag alloy and its preparation and application to solve any one of the above and other potential problems in the prior art.

[0006] To solve the above technical problems, the technical solution of the present invention is: a low-cost heat-resistant Al-Cu-Mg-Ag alloy, and the mass percentages of the components of the heat-resistant Al-Cu-Mg-Ag alloy are as follows: 4.00% - 4.50% of Cu, 0.10% - 0.30% of Mg, 0.10% - 0.20% of Ag, 0.10% - 0.30% of Mn, 0.05% - 0.15% of Zr, 0.05% - 0.15% of Ti, 0.05% - 0.20% of Si, and the balance is Al and inevitable impurities, and the total sum of Fe and Ni elements in the impurities < 0.15%.

[0007] Further, the heat-resistant Al-Cu-Mg-Ag alloy further includes: 0.0% - 0.15% of Cr, 0.0% - 0.20% of Mo.

[0008] Further, the heat-resistant Al-Cu-Mg-Ag alloy has multi-level and multi-scale dispersion strengthening phases and precipitation strengthening phases.

[0009] Further, the dispersion strengthening phases include Al3(Zr,Ti) and Al6(Mn,Fe);

[0010] Or the dispersion strengthening phases include Al3(Zr,Ti), Al7(Cr,Mn), and Al6(Mn,Fe,Mo);

[0011] The precipitation strengthening phase is the θ' phase and the L 12 phase.

[0012] Another object of the present invention is to provide a method for preparing the above heat-resistant Al-Cu-Mg-Ag alloy, and the method specifically includes the following steps:

[0013] S1) Casting: Using pure aluminum, industrial pure magnesium, aluminum-copper master alloy, aluminum-silver master alloy, aluminum-manganese master alloy, aluminum-chromium master alloy, aluminum-zirconium master alloy, aluminum-molybdenum master alloy, aluminum-silicon master alloy, and aluminum-titanium master alloy as raw materials, melt the alloy with the melting temperature controlled at 750 - 800 °C, and then cast it into alloy ingots.

[0014] S2) Homogenization treatment: Perform homogenization treatment on the cast ingots obtained in S1).

[0015] S3) Deformation treatment: Perform deformation treatment on the ingots homogenized in S2).

[0016] S4) Solution treatment: Perform solution treatment on the samples after deformation treatment in S3).

[0017] S5) Aging treatment: Perform aging treatment on the samples after solution treatment in S4), and then the low-cost heat-resistant Al-Cu-Mg-Ag alloy is obtained.

[0018] Furthermore, the casting method in S1) is preferably semi-continuous casting, or alloy ingots can be obtained by casting methods such as permanent mold casting, die casting, or continuous casting according to the actual production situation.

[0019] Furthermore, the homogenization treatment process in S2) is as follows: Heat the ingots melted in step (1) to 450 - 480 °C, hold for 6 - 12 h, then heat to 520 - 560 °C, hold for 6 - 24 h, and then take them out of the furnace and air-cool to room temperature.

[0020] Furthermore, the deformation treatment process in S3) is as follows: Perform hot rolling at a temperature of 400 - 470 °C for 0.5 - 1.5 h. After hot rolling, the samples are subjected to intermediate annealing treatment at a temperature of 380 - 420 °C for 0.5 - 1.5 h and then air-cooled, and then cold rolling is carried out with a cold deformation amount of more than 60%.

[0021] Furthermore, the solution treatment process in S4) is as follows: Hold at a temperature of 530 - 550 °C for 1 - 4 h, and then perform water quenching at room temperature.

[0022] Furthermore, the aging treatment process in S5) is as follows: Hold at a temperature of 160 - 210 °C for 4 - 50 h, and then air-cool to room temperature.

[0023] An above-mentioned heat-resistant Al-Cu-Mg-Ag alloy is applied in the aerospace field.

[0024] The beneficial effects of the present invention are as follows: Due to the adoption of the above technical solutions, the Al-Cu-Mg-Ag alloy designed by the present invention significantly improves its high-temperature performance while maintaining the same room-temperature strength and plasticity as the 2040 alloy: After thermal exposure at 200°C for 100 h, the yield strength retention rate is as high as over 86% (an increase of over 25% compared to the 2040 alloy); the creep performance under the condition of 210°C / 190 MPa is improved by over 30% compared to the 2040 alloy.

[0025] The Ag content of the Al-Cu-Mg-Ag alloy designed by the present invention is as low as 0.1 - 0.2 wt.%, far lower than the 0.4 - 0.7 wt.% Ag of the 2040 alloy. Compared with it, the raw material cost per ton is reduced by 16,500 - 40,500 yuan, saving 28 - 50%. At the same time, the reduction of the Ag content in the present invention can reduce the dendritic segregation during the solidification of aluminum alloy and improve the quality of ingots.

[0026] The Al-Cu-Mg-Ag alloy designed by the present invention appropriately reduces the contents of Cu, Mg, Ag, and Mn, and compositely adds trace alloying elements such as Zr, Ti, Cr, Mo, and Si to achieve a reasonable match of components, significantly increasing the burnover temperature of the alloy. After solution + aging treatment, only a small amount of micron-sized second phases remain in the alloy matrix, and at the same time, multi-level and multi-scale dispersion strengthening phases and precipitation strengthening phases are formed, achieving a good balance between strength and plasticity while reducing costs.

[0027] The aluminum alloy of the present invention is manufactured by the industrial production process of conventional aluminum alloy materials: casting → homogenization → deformation treatment → solution treatment → aging treatment, which is suitable for large-scale industrial production and application of heat-resistant aluminum alloys. Description of the Drawings

[0028] Figure 1 It is a flow block diagram of the preparation method of a low-cost heat-resistant Al-Cu-Mg-Ag alloy of the present invention.

[0029] Figure 2 It is a schematic diagram of the DSC test results of the aluminum alloy prepared in Example 1 of the present invention and the 2040 alloy in the as-cast state;

[0030] Figure 3 It is a schematic diagram of the microstructural morphology of the aluminum alloy prepared in Example 1 of the present invention and the 2040 alloy in the solution state;

[0031] Figure 4 It is a schematic diagram of the typical dispersion phase morphology of the aluminum alloy prepared in Example 1 of the present invention and the 2040 alloy in the T6 state;

[0032] Figure 5 It is a schematic diagram of the typical precipitation phase morphology of the aluminum alloy prepared in Example 1 of the present invention and the 2040 alloy in the T6 state;

[0033] Figure 6 Schematic diagram of the typical precipitation phase morphology of the aluminum alloy prepared in Example 1 of the present invention and the 2040 alloy in the T6 + 200 °C / 100 h thermal exposure state. Detailed implementation manners

[0034] The technical solutions of the present invention will be further described below in conjunction with the embodiments.

[0035] As Figure 1 shown, a preparation method of a low-cost heat-resistant Al-Cu-Mg-Ag alloy of the present invention has the following preparation steps:

[0036] S1) Casting: Using pure aluminum, industrial pure magnesium, aluminum-copper master alloy (Al-50 wt.% Cu), aluminum-silver master alloy (Al-10 wt.% Ag), aluminum-manganese master alloy (Al-10 wt.% Mn), aluminum-chromium master alloy (Al-5 wt.% Cr), aluminum-zirconium master alloy (Al-10 wt.% Zr), aluminum-molybdenum master alloy (Al-5 wt.% Mo), aluminum-silicon master alloy (Al-10 wt.% Si), and aluminum-titanium master alloy (Al-10 wt.% Ti) as raw materials, melting the alloy, controlling the melting temperature at 750 - 800 °C, and then casting it into an alloy ingot;

[0037] S (2) Homogenization treatment: subjecting the ingot cast in S (1) to homogenization treatment;

[0038] S3) Deformation treatment: subjecting the homogenized ingot in S2) to deformation treatment;

[0039] S4) Solution treatment: subjecting the sample after deformation treatment in S3) to solution treatment;

[0040] S5) Aging treatment: subjecting the sample after solution treatment in S4) to aging treatment to obtain a low-cost heat-resistant Al-Cu-Mg-Ag alloy.

[0041] The present invention combines thermodynamic calculations and machine learning methods to analyze the composition-property data of publicly reported Al-Cu-Mg-Ag alloys, optimizes the contents of elements such as Cu, Mg, Ag, Mn, Zr, Ti, Cr, and Mo, and achieves a good balance between high strength and plasticity and heat resistance. Compared with the 2040 alloy, the present invention reduces the contents of easily burned elements such as Zn and Mg, raising the overburn temperature of the alloy to above 550 °C (see Figure 2 ), and at the same time reduces the contents of elements such as Cu and Ag, leaving only a small amount of micron-sized phases in the alloy after solution treatment (see Figure 3), effectively improving the tissue uniformity of the alloy. In addition, by regulating elements such as Mn, Zr, Ti, Cr, and Mo, dispersion strengthening phases such as Al3(Zr,Ti), Al7(Cr,Mn), and Al6(Mn,Fe,Mo) are formed (see Figure 4 ), improving the strength of the alloy and reducing the adverse effects brought by Fe impurities. On this basis, adding Si element inhibits the precipitation of Ω phase and promotes the formation of θ' phase and L 12 phase (see Figure 5 ), and the obtained combination of θ' phase and L 12 phase has better thermal stability than the Ω phase (see Figure 6 ), significantly improving the strength of the alloy under 200 °C thermal exposure (see Tables 1 - 3).

[0042] Example 1:

[0043] A low - cost heat - resistant Al - Cu - Mg - Ag alloy, the mass percentages of each component of the alloy are: Cu content is 4.45 wt.%, Mg content is 0.27 wt.%, Ag content is 0.14 wt.%, Mn content is 0.25 wt.%, Zr content is 0.12 wt.%, Ti content is 0.09 wt.%, Cr content is 0.08 wt.%, Mo content is 0.13 wt.%, Si content is 0.11 wt.%, and the balance is Al.

[0044] The preparation method of the present invention is as follows:

[0045] Casting: Using pure aluminum, industrial pure magnesium, aluminum - copper master alloy (Al - 50 wt.% Cu), aluminum - silver master alloy (Al - 10 wt.% Ag), aluminum - manganese master alloy (Al - 10 wt.% Mn), aluminum - zirconium master alloy (Al - 10 wt.% Zr), aluminum - chromium master alloy (Al - 5 wt.% Cr), aluminum - molybdenum master alloy (Al - 5 wt.% Mo), aluminum - silicon master alloy (Al - 10 wt.% Si), aluminum - titanium master alloy (Al - 10 wt.% Ti) as raw materials, melting and composition blending are completed under the control of 780 °C. Subsequently, after the melt is refined, degassed, and filtered, a semi - continuous casting process is adopted, and controlled solidification is achieved through a water - cooled crystallizer, while a hydraulic system is used to control the slow downward movement of the ingot for forming. After casting, the ingot is naturally air - cooled to room temperature;

[0046] Homogenization: The ingot melted in (1) is heated to 470 °C, held for 12 h, then heated to 540 °C, held for 24 h, and then taken out of the furnace and air - cooled to room temperature;

[0047] Deformation treatment: The homogenized ingot in (2) is hot-rolled after holding at 470 °C for 1 h, and the hot-rolled sample is air-cooled after intermediate annealing treatment at 400 °C for 1 h, and then cold-rolled with a cold deformation of 75%.

[0048] Solution treatment: The sample after deformation treatment in (3) is heated to 550 °C, held for 1 h, and then quenched in room temperature water;

[0049] Aging treatment: The sample after solution treatment in (4) is aged at 185 °C for 16 h to obtain a low-cost heat-resistant Al-Cu-Mg-Ag alloy.

[0050] For performance comparison, the 2040 alloy was prepared by the same method as the present invention, and solution treatment at 10 °C below the overburning temperature and peak aging treatment at 185 °C were carried out on it. Subsequently, room temperature tensile tests were carried out on Example 1 and the 2040 alloy in the T6 state and the T6 + 200 °C / 100 h thermal exposure state, and their mechanical properties are shown in Table 1. It can be seen from Table 1 that the room temperature strength of Example 1 is similar to that of the 2040 alloy, but after the 200 °C / 100 h thermal exposure treatment, the strength of Example 1 is significantly better than that of the 2040 alloy, and its yield strength retention rate reaches 86.5%, much higher than 67.9% of the 2040 alloy. In addition, in the creep strength test under the conditions of 210 °C / 190 MPa, Example 1 showed better creep properties than the 2040 alloy, and the creep strength duration increased from 144 h to 204 h, an increase of 41.6%. The results show that the aluminum alloy prepared in Example 1 of the present invention has more excellent heat resistance.

[0051] Table 1 Performance comparison between the aluminum alloy prepared in Example 1 of the present invention and the 2040 alloy

[0052]

[0053] * Yield strength retention rate: The ratio of the room temperature yield strength after thermal exposure to that before thermal exposure

[0054] Example 2:

[0055] A low-cost heat-resistant Al-Cu-Mg-Ag alloy, the mass percentages of the respective components of the alloy are: Cu content is 4.13 wt.%, Mg content is 0.29 wt.%, Ag content is 0.11 wt.%, Mn content is 0.30 wt.%, Zr content is 0.14 wt.%, Ti content is 0.11 wt.%, Si content is 0.10 wt.%, and the balance is Al.

[0056] The preparation method is as follows:

[0057] Casting: Using pure aluminum, industrial pure magnesium, aluminum-copper master alloy (Al-50wt.% Cu), aluminum-silver master alloy (Al-10wt.% Ag), aluminum-manganese master alloy (Al-10wt.% Mn), aluminum-zirconium master alloy (Al-10wt.% Zr), aluminum-molybdenum master alloy (Al-5wt.% Mo), aluminum-silicon master alloy (Al-10wt.% Si), and aluminum-titanium master alloy (Al-10wt.% Ti) as raw materials, alloy melting is completed at 750°C, followed by refining degassing and melt purification treatment. Subsequently, the treated melt is transferred to a continuous casting equipment under temperature control, and rapid solidification is achieved through a mold, and continuously drawn out to form an aluminum alloy ingot. The ingot is air-cooled or water-spray cooled and then air-cooled to room temperature;

[0058] Homogenization: The ingot melted in (1) is heated to 480°C and held for 6h, then heated to 520°C and held for 12h, and then taken out of the furnace and air-cooled to room temperature;

[0059] Deformation treatment: The homogenized ingot in (2) is held at 400°C for 1.5h for hot rolling. The hot-rolled sample is air-cooled after intermediate annealing treatment at 380°C for 1.5h, and then cold rolling is carried out with a cold deformation of 70%.

[0060] Solution treatment: The sample after deformation treatment in (3) is heated to 540°C and held for 2h, and then quenched in room temperature water;

[0061] Aging treatment: The sample after solution treatment in (4) is aged at 210°C for 5 hours to obtain a low-cost heat-resistant Al-Cu-Mg-Ag alloy.

[0062] The performance comparison between the aluminum alloy prepared in Example 2 of the present invention and the 2040 alloy is shown in Table 2,

[0063] The room temperature strength of Example 2 is similar to that of the 2040 alloy, but after heat exposure treatment at 200°C / 100h, the strength of Example 2 is significantly better than that of the 2040 alloy, and its yield strength retention rate reaches 88.3%, much higher than 67.9% of the 2040 alloy. In addition, in the creep strength test under the condition of 210°C / 190MPa, Example 2 shows better creep performance than the 2040 alloy, and its creep strength duration is increased from 144h to 188h, an increase of 31.9%.

[0064] Table 2 Performance comparison between the aluminum alloy prepared in Example 2 of the present invention and the 2040 alloy

[0065]

[0066] * Yield strength retention rate: The ratio of the room temperature yield strength after heat exposure to that before heat exposure

[0067] Example 3:

[0068] A low-cost heat-resistant Al-Cu-Mg-Ag alloy, the mass percentages of the respective components of the alloy are as follows: the Cu content is 4.49 wt.%, the Mg content is 0.25 wt.%, the Ag content is 0.18 wt.%, the Mn content is 0.29 wt.%, the Zr content is 0.09 wt.%, the Ti content is 0.12 wt.%, the Cr content is 0.05 wt.%, the Mo content is 0.15 wt.%, the Si content is 0.15 wt.%, and the balance is Al.

[0069] The preparation method is as follows:

[0070] Casting: Using pure aluminum, industrial pure magnesium, aluminum-copper master alloy (Al-50 wt.% Cu), aluminum-silver master alloy (Al-10 wt.% Ag), aluminum-manganese master alloy (Al-10 wt.% Mn), aluminum-chromium master alloy (Al-5 wt.% Cr), aluminum-zirconium master alloy (Al-10 wt.% Zr), aluminum-silicon master alloy (Al-10 wt.% Si), and aluminum-titanium master alloy (Al-10 wt.% Ti) as raw materials, melting and composition adjustment are completed under the control of 800 °C. Subsequently, after the melt is refined, degassed, and filtered, a semi-continuous casting process is adopted, and controlled solidification is achieved through a water-cooled mold, while the hydraulic system is used to control the slow downward movement of the ingot for forming. After casting is completed, the ingot is naturally air-cooled to room temperature;

[0071] Homogenization: The ingot melted in (1) is heated to 475 °C, held for 12 h, then heated to 535 °C, held for 6 h, and then taken out of the furnace and air-cooled to room temperature;

[0072] Deformation treatment: The homogenized ingot in (2) is hot-rolled at 450 °C for 0.5 h. After the hot-rolled sample is subjected to an intermediate annealing treatment at 420 °C for 0.5 h and then air-cooled, cold rolling is then carried out, and the cold deformation amount is 80%.

[0073] Solution treatment: The sample after deformation treatment in (3) is heated to 560 °C, held for 1 h, and then quenched in room temperature water;

[0074] Aging treatment: The sample after solution treatment in (4) is aged at 165 °C for 48 hours to obtain a low-cost heat-resistant Al-Cu-Mg-Ag alloy.

[0075] The performance comparison between the aluminum alloy prepared in Example 3 of the present invention and the 2040 alloy is shown in Table 3. The room temperature strength of Example 3 is similar to that of the 2040 alloy. However, after the thermal exposure treatment at 200 °C for 100 h, the strength of Example 3 is significantly better than that of the 2040 alloy, and its yield strength retention rate reaches 88.5%, which is much higher than 67.9% of the 2040 alloy. In addition, in the creep strength test under the conditions of 210 °C / 190 MPa, Example 1 shows better creep performance than the 2040 alloy, and the creep strength duration is increased from 144 h to 197 h, an increase of 36.8%.

[0076] Table 3 Performance comparison between the aluminum alloy prepared in Example 3 of the present invention and the 2040 alloy

[0077]

[0078] * Yield strength retention rate: The ratio of the room temperature yield strength after thermal exposure to that before thermal exposure.

[0079] The above has introduced in detail a low-cost heat-resistant Al-Cu-Mg-Ag alloy and its preparation and application provided by 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 of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

[0080] As certain terms 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 terms to refer to the same component. The specification and claims do not use the difference in names as a way to distinguish components, but use the difference in functions of components as the criterion for distinction. As mentioned throughout the specification and claims, "comprising" and "including" are open-ended terms, so they should be interpreted as "comprising / including but not limited to". "Substantially" means 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 in the specification is the preferred implementation manner for implementing the present application, but the description is for the purpose of explaining the general principle of the present application and is not used to limit the scope of the present application. The protection scope of the present application shall be subject to what is defined by the appended claims.

[0081] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a commodity or system comprising a series of elements not only includes those elements but also other elements not expressly listed, or elements inherent to such commodity or system. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the commodity or system comprising said element.

[0082] It should be understood that the term "and / or" used herein is merely a correlative relationship describing associated objects, indicating that three relationships may exist. For example, A and / or B may represent: the sole existence of A, the simultaneous existence of A and B, and the sole existence of B. Additionally, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0083] The above description illustrates and describes several preferred embodiments of the present application. However, as previously mentioned, it should be understood that the present application is not limited to the forms disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the above teachings or the techniques or knowledge in the relevant field. Any alterations and changes made by those skilled in the art that do not depart from the spirit and scope of the present application shall fall within the protection scope of the appended claims of the present application.

Claims

1. A low-cost heat-resistant Al-Cu-Mg-Ag alloy, characterized in that, The mass percentages of the respective components of the heat-resistant Al-Cu-Mg-Ag alloy are as follows: 4.00% to 4.50% of Cu, 0.10% to 0.30% of Mg, 0.10% to 0.20% of Ag, 0.10% to 0.30% of Mn, 0.05% to 0.15% of Zr, 0.05% to 0.15% of Ti, 0.05% to 0.20% of Si, with the balance being Al and inevitable impurities, and the total sum of Fe and Ni elements in the impurities < 0.15%.

2. The heat-resistant Al-Cu-Mg-Ag alloy according to claim 1, characterized in that, The heat-resistant Al-Cu-Mg-Ag alloy further includes: 0.0% to 0.15% of Cr, 0.0% to 0.20% of Mo.

3. The heat-resistant Al-Cu-Mg-Ag alloy according to claim 1 or 2, characterized in that, The heat-resistant Al-Cu-Mg-Ag alloy has multi-level and multi-scale dispersion strengthening phases and precipitation strengthening phases.

4. The heat-resistant Al-Cu-Mg-Ag alloy according to claim 3, characterized in that, The dispersion strengthening phases include Al3(Zr,Ti) and Al6(Mn,Fe); or the dispersion strengthening phases include Al3(Zr,Ti), Al7(Cr,Mn) and Al6(Mn,Fe,Mo); The precipitation strengthening phases are θ' phase and L 12 phase.

5. A method for preparing a heat-resistant Al-Cu-Mg-Ag alloy as described in any one of claims 1-4, characterized in that, The method specifically includes the following steps: S1) Casting: Using pure aluminum, industrial pure magnesium, aluminum-copper master alloy, aluminum-silver master alloy, aluminum-manganese master alloy, aluminum-chromium master alloy, aluminum-zirconium master alloy, aluminum-molybdenum master alloy, aluminum-silicon master alloy, aluminum-titanium master alloy as raw materials, melting the alloy, controlling the melting temperature at 750 - 800 °C, and then casting into alloy ingots; S2) Homogenization treatment: Performing homogenization treatment on the casting ingots obtained in S1); S3) Deformation treatment: Performing deformation treatment on the ingots homogenized in S2); S4) Solution treatment: Performing solution treatment on the samples after the deformation treatment in S3); S5) Aging treatment: Performing aging treatment on the samples after the solution treatment in S4), namely obtaining a low-cost heat-resistant Al-Cu-Mg-Ag alloy.

6. The method according to claim 5, characterized in that, The homogenization treatment process in S2) is: Heating the ingots melted in S1) to a temperature of 450 - 480 °C, holding for 6 - 12 h, then raising the temperature to 520 - 560 °C, holding for 6 - 24 h, and then taking out of the furnace and air-cooling to room temperature.

7. The method according to claim 5, characterized in that The deformation treatment process in S3) is: Performing hot rolling at a temperature of 400 - 470 °C for 0.5 - 1.5 h, the samples after hot rolling are air-cooled after intermediate annealing treatment at a temperature of 380 - 420 °C for 0.5 - 1.5 h, and then cold rolling is carried out, and the cold deformation amount is more than 60%.

8. The method according to claim 5, wherein The solution treatment process in S4) is: Holding at a temperature of 530 - 550 °C for 1 - 4 h, and then quenching in room temperature water.

9. The method according to claim 5, wherein The aging treatment process in S5) is: Holding at a temperature of 160 - 210 °C for 4 - 50 h, and then air-cooling to room temperature.

10. An application of the heat-resistant Al-Cu-Mg-Ag alloy according to any one of claims 1 - 4 in the aerospace field.

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