WO2021008428A1

WO2021008428A1 - Ultrahigh-strength aluminum-lithium alloy and preparation method therefor

Info

Publication number: WO2021008428A1
Application number: PCT/CN2020/100982
Authority: WO
Inventors: 肖代红; 刘文胜; 吴名冬; 陈炜斌
Original assignee: 中南大学
Priority date: 2019-07-17
Filing date: 2020-07-09
Publication date: 2021-01-21
Also published as: CN110423927A

Abstract

An ultrahigh-strength aluminum-lithium alloy and a preparation method therefor. The alloy comprises the following components by mass percentage: 4.3%-5.2% Cu, 0.8%-1.2% Li, 0.3%-0.7% Mg, 0.1%-0.5% Ag, 0.81%-1.5% Zn, 0.1%-0.2% Mn, 0.1%-0.2% Zr, 0.09%-0.3% Sc, wherein the remainder is Al, and mass percentage ratio of Cu/Li is 4.3 to 6.5. The preparation method therefor is: weighing the components according to the designed aluminum alloy component ratio, using atmospheric smelting or vacuum smelting to cast a molded cast ingot, and then performing a multi-stage homogenization treatment, hot extrusion deformation, step-by-step heating and solid solution, cold rolling deformation and an aging treatment. A product which has a superior performance compared to that of an existing aluminum-lithium alloy is prepared, and the product has the characteristics of having a high yield strength, high hardness, high modulus of elasticity, being capable of being strengthened by a heat treatment, etc.

Description

Ultra-high-strength aluminum-lithium alloy and preparation method thereof

Technical field

The invention relates to an ultra-high-strength aluminum-lithium alloy and a preparation method thereof; it belongs to the technical field of metal material preparation.

Background technique

For every 1wt% Li added to the aluminum alloy, the alloy density can be reduced by 3%, while the elastic modulus can be increased by 6%, and it has a better solid solution strengthening effect. Therefore, aluminum-lithium alloy has the advantages of low density, high specific strength and specific rigidity, fatigue resistance and corrosion resistance. Replacing conventional aluminum alloy with aluminum-lithium alloy can reduce the structural quality by 10%-15% and increase the rigidity by 15%-20%. It is an ideal aerospace structural material. With the development of my country's aerospace industry, new low-density aluminum alloys have been continuously developed, but the existing aluminum-lithium alloy production has problems such as difficulty, high cost, and low strength.

Al-lithium alloys have been developed to the third generation of Al-Cu-Li alloys, mainly by adjusting the content of main alloying elements and microalloying elements in the alloy, and at the same time by processing deformation and thermomechanical heat treatment to improve its comprehensive performance. Chinese patent (Patent No. 201380023370.0) discloses a new 2xxx aluminum-lithium alloy, the aluminum alloy contains 3.5-4.4wt.% Cu, 0.45-0.75wt.% Mg, 0.45-0.75wt.% Zn, 0.65-1.15wt. %Li, the alloy is an aluminum-lithium alloy with low zinc content, and the Zn/Mg mass fraction ratio is between 0.60-1.67. At the same time, the alloy requires a magnesium content of less than 1%, but the alloy has low fracture toughness. Chinese patent (Patent No. 201810444457.X) discloses a high-strength and toughness extrusion-deformed aluminum-lithium alloy with high Zn content and its preparation method. The components in the alloy are: Zn 4 .1-5.5%, Cu 2- 4.5%, Mg 2-3%, Li 1-2%, Zr 0.1-0.5%, but the magnesium content in this alloy exceeds 2%, which will cause a large amount of T ₁ phase to precipitate at the grain boundary and reduce The strength of the grain boundary is reduced, thereby reducing the fracture toughness of the alloy. China Aviation Development Beijing Institute of Aeronautical Materials has developed an alloy in its patents CN107779705A, an aluminum-lithium alloy and rolling method, CN107779706A, an aluminum-lithium alloy and extrusion method, and CN108004445B, an aluminum-lithium alloy and forging method. The mass fraction of the components is Cu: 3%～4.2%; Mg 0.2%～1.4%; Li: 0.6%～1.5%; Ag: 0～1%; Zr: 0.06%～0.15%; Mn: 0.2%～0.6% Zn: 0～0.8%; Si≤0.08%; Fe≤0.10%; other impurities individually≤0.05%; the total amount of other impurities≤0.15%, the balance is Al. It can meet the current needs, but its maximum strength is only 663MPa; and it does not involve the optimization of key parameters such as elastic modulus. As people have higher and higher requirements for comprehensive mechanical properties such as the strength and elastic modulus of aluminum-lithium alloys, how to meet the requirements of the next generation of flying equipment has become the focus and difficulty of aluminum-lithium alloy research. Based on this, the present invention proposes A new type of ultra-high-strength aluminum-lithium alloy with tensile strength greater than 680MPa and elastic modulus of 77-81GPa.

technical problem

In order to meet the requirements of next-generation flying equipment, the present invention designs and prepares a new type of ultra-high-strength aluminum-lithium alloy with a tensile strength greater than 680 MPa and an elastic modulus of 77-81 GPa.

Technical solutions

The present invention regulates the content and proportion of main elements (Li, Cu), the content of trace strengthening elements (Mg, Ag, Zn) and grain control elements (Zr, Mn, Sc), combined with appropriate multi-stage homogenization annealing process, Gradually heating and solid solution process, cold rolling deformation and aging treatment process conditions, to obtain an age-strengthened aluminum-lithium alloy with excellent mechanical properties, and the prepared aluminum alloy has superior room temperature tensile strength, hardness, elastic modulus, etc. Mechanical behavior. A proper amount of Cu, Li and the ratio of the two are helpful to obtain a mixed structure of δ'(Al ₃ Li), θ'(Al ₂ Cu), and T ₁ (Al ₂ CuLi) phases and obtain higher strength. The addition of high Cu content has two effects: one is to increase the stacking fault energy of the δ′ phase, and the dislocation changes from the original cut-through mechanism to the bypass mechanism, which reduces the coplanar slippage and thus facilitate uniform deformation, improved ductility of the alloy, on the other hand can promote nucleation and precipitation of δ 'phase and the phase T _l, T ₁ with a larger size can not easily be cut through dislocations can significantly improve the strength of the alloy. Appropriate addition of Mg and Ag at the same time will help the formation of T1 phase and inhibit the transition of δ'phase to equilibrium phase δ, thereby reducing the harmful effects of grain boundary precipitation without precipitation zone, but when the content of Mg is too much, the T ₁ phase will be at the grain boundary Prioritize precipitation, leading to a sharp increase in the brittleness of the alloy and a serious decrease in plasticity. The addition of Cu and Mg at the same time easily forms the acicular metastable S'(A1 ₂ CuMg) phase, which effectively prevents coplanar slippage and improves the strength and toughness of the alloy. The proper amount of Zr, Mn, and Sc are dispersed and precipitated into proper amount of Al ₃ Zr, Al ₂₀ Cu ₂ Mn ₃ , Al ₆ Mn, Al ₃ Sc particles during proper multi-level homogenization treatment to control recrystallization and reduce strain localization Change (strain localization reduces strength). Mn can also eliminate the adverse effects of the impurity element Fe and improve the corrosion resistance of the alloy. Sc purifies the alloy, refines the grains, and has the effect of transition group elements to inhibit recrystallization. It can change the morphology, size and distribution of the main strengthening phases such as δ'(Al ₃ Li) and S'(A1 ₂ CuMg) The situation has changed the location and propagation path of cracks, thereby improving the damage resistance of the alloy. Zn has solid solution strengthening and aging strengthening effects. Adding Zn to the aluminum-lithium alloy can form η'(Mg ₂ Zn) phase, which is a strengthening phase with a greater strengthening effect; Zn can also promote the S'and T1 phase Precipitate, thereby improving its strong plasticity.

An ultra-high-strength aluminum-lithium alloy of the present invention includes the following components in mass percentage: Cu 4.3-5.2%, Li 0.8-1.2%, Mg 0.3-0.7%, Ag 0.1-0.5%, Zn 0.81～1.5%, Mn 0.1～0.2%, Zr 0.1～0.2%, Sc 0.09～0.3%, Cu/Li mass fraction ratio 4.3～6.5, the balance is Al. After optimization, the tensile strength of the ultra-high-strength aluminum-lithium alloy is greater than 680 MPa, and the elastic modulus is 77-81 GPa.

As a preferred solution, an ultra-high-strength aluminum-lithium alloy of the present invention includes the following components in mass percentage: Cu 4.86%, Li 0.87%, Mg 0.5%, Ag 0.3%, Zn 1.0%, Mn 0.2%, Zr 0.15% , Sc 0.09%, the balance is Al.

As a preferred solution, an ultra-high-strength aluminum-lithium alloy of the present invention includes the following components in mass percentage: Cu 4.3%, Li 1%, Mg 0.5%, Ag 0.3%, Zn 0.81%, Mn 0.15%, Zr 0.15% , Sc 0.09%, the balance is Al.

As a preferred solution, an ultra-high-strength aluminum-lithium alloy of the present invention includes the following components in mass percentage: Cu 5.2%, Li 1%, Mg 0.45%, Ag 0.3%, Zn 1.0%, Mn 0.15%, Zr 0.1% , Sc 0.15%, the balance is Al.

The invention discloses a method for preparing an ultra-high-strength aluminum-lithium alloy. According to a designed aluminum alloy composition ratio, each component is weighed, and the aluminum, lithium, aluminum-copper master alloy, magnesium, silver, Aluminum-zirconium master alloy, aluminum-manganese master alloy, aluminum-scandium master alloy and zinc are melted, degassed and slag removed, cast into ingots, and then the ingots are subjected to multi-level homogenization treatment, hot extrusion deformation, and gradual heating and solid solution. Cold rolling deformation and timely treatment. The composition ratio is reasonable, the process operation safety cost is low, and the prepared aluminum alloy has good comprehensive mechanical properties.

The method for preparing an ultra-high-strength aluminum-lithium alloy of the present invention includes the following steps.

According to the designed distribution ratio of aluminum alloy components, weigh each component, and use atmospheric melting or vacuum melting to combine aluminum, lithium, aluminum-copper master alloy, magnesium, silver, aluminum-zirconium master alloy, aluminum-manganese master alloy, aluminum-scandium master alloy and Zinc is melted, degassed and slag removed, cast into ingots, and then the ingots undergo multi-stage homogenization treatment, hot extrusion deformation, multi-stage solid solution, cold rolling deformation and timely treatment.

As a preferred solution, the present invention is an ultra-high-strength aluminum-lithium alloy preparation method; the cast-shaped aluminum-lithium alloy ingot is subjected to multi-stage homogenization annealing treatment. The annealing process is: heating to 380~420℃ for 1~5h, and then heating to Keep 450~480℃ for 5~10h, then heat to 490~510℃ for 12~24h.

As a preferred solution, the present invention is an ultra-high-strength aluminum-lithium alloy preparation method; the homogenized annealed ingot is hot-extruded into a plate, the extrusion temperature is 430-460°C, and the extrusion ratio is 5-20.

As a preferred solution, the present invention is an ultra-high-strength aluminum-lithium alloy preparation method; the hot-extruded plate alloy is gradually heated and solid-solution and quenched. The solid-solution process is: heating to 400~450°C for 1~2h, and then heating to 470 Keep it at ~490℃ for 0.5~1h, then heat it to 510~530℃ for 0.5~1h. After the solution treatment, the water is cooled to room temperature.

As a preferred solution, the present invention is a method for preparing an ultra-high-strength aluminum-lithium alloy; the material after gradual heating and solid solution and quenching is subjected to cold rolling deformation with a deformation amount of 3-20%.

As a preferred solution, the present invention is a method for preparing an ultra-high-strength aluminum-lithium alloy; the cold-rolled deformed sample is subjected to aging treatment at a temperature of 130 to 170° C. and a time of 10 to 50 hours.

As a further preferred solution, the present invention is an ultra-high-strength aluminum-lithium alloy preparation method; when the designed alloy includes the following components in mass percentage: Cu 4.86%, Li 0.87%, Mg 0.5%, Ag 0.3%, Zn 1.0% , Mn 0.2%, Zr 0.15%, Sc 0.09%, and the balance is Al; its preparation method is: under vacuum, in turn, pure aluminum, aluminum-copper intermediate alloy, aluminum-zirconium intermediate alloy, aluminum-scandium intermediate alloy pure zinc, Pure magnesium and pure silver are melted in a melting furnace, and cast in a static state; the ingot is subjected to multi-stage homogenization annealing treatment. The annealing process is: 400℃ for 5 hours, then heated to 480℃ for 5 hours, and then heated to 510℃ for insulation 12h; the annealed sample is extruded into a sheet at 450°C with an extrusion ratio of 10; the hot-extruded sheet alloy undergoes gradual heating and solid solution and quenching treatment. The solution process is: heating to 450°C for 1.5h, then heating to 490°C Hold for 0.5h, then heat to 530℃ for 0.5h; after solution treatment, cool to room temperature in water; then carry out cold rolling deformation, cold rolling deformation is 20%; samples after cold rolling deformation are subjected to aging treatment, aging temperature 160 ℃, time 30h, get the finished product.

As a further preferred solution, the present invention is an ultra-high-strength aluminum-lithium alloy preparation method; when the designed alloy includes the following components in mass percentage: Cu 4.3%, Li 1%, Mg 0.5%, Ag 0.3%, Zn 0.81% , Mn 0.15%, Zr 0.15%, Sc 0.09%, the balance is Al; its preparation method is as follows: in the atmospheric environment, the pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, pure The silver is melted in a smelting furnace, and a covering agent is sprinkled on the surface; then pure lithium is pressed into the molten alloy melt, argon is used for degassing and slag refining, static casting is formed; the ingot is uniformly multi-stage Chemical annealing treatment, the annealing process is: heat preservation at 420°C for 3h, then heat to 470°C for 8h, and then heat to 500°C for 24h; the annealed sample is extruded into a plate at 450°C with an extrusion ratio of 10; hot-extruded plate alloy Carry out the gradual heating solution and quenching treatment. The solution process is: heating to 450°C for 1h, then heating to 500°C for 0.5h, then heating to 530°C for 0.5h; after solution treatment, water cooling to room temperature. Gradually heat up the solution and quench the material after cold rolling deformation, the deformation amount is 10%; the sample after cold rolling deformation is subjected to aging treatment, the aging temperature is 160℃, and the time is 36h, and the finished product is obtained. In the above two further preferred solutions, due to the proper combination of the process and the components, the performance of the product is significantly improved. This greatly exceeded the expectations before the experiment.

As a further preferred solution, the present invention is an ultra-high-strength aluminum-lithium alloy preparation method; when the designed alloy includes the following components in mass percentage: Cu 5.2%, Li 1%, Mg 0.45%, Ag 0.3%, Zn 1.0% , Mn 0.15%, Zr 0.1%, Sc 0.15%, the balance is Al; its preparation method is: in the atmospheric environment, sequentially combine pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, pure The silver is melted in a smelting furnace, and a covering agent is sprinkled on the surface; then pure lithium is pressed into the molten alloy melt, argon is used for degassing and slag refining, static casting is formed; the ingot is uniformly multi-stage Chemical annealing treatment, the annealing process is: heat preservation at 420°C for 3h, then heat to 470°C for 8h, and then heat to 500°C for 24h; the annealed sample is extruded into a plate at 450°C with an extrusion ratio of 10; hot-extruded plate alloy Carry out gradual heating solution and quenching treatment. The solution process is: heating to 450℃ for 1h, then heating to 500℃ for 0.5h, and then heating to 530℃ for 0.5h. ; After the solution treatment is completed, cool to room temperature in water; gradually heat up the solution and quench the material to undergo cold rolling deformation, with a deformation amount of 10%; the samples after cold rolling deformation are subjected to aging treatment at an aging temperature of 160°C for 36 hours to obtain the finished product .

The aluminum-lithium alloy prepared by this process has a maximum tensile strength of more than 700 MPa, a yield strength of more than 630 MPa, an elongation of 12%, and an elastic modulus of 81 GPa after subsequent deformation heat treatment.

The aluminum-lithium alloy prepared by this process method can adjust the content and ratio of main elements (Li, Cu), the content of micro strengthening elements (Mg, Ag, Zn) and grain control elements (Zr, Mn, Sc), and multi-level Homogenizing annealing process, gradual heating and solid solution process, cold rolling deformation and aging treatment process conditions, to obtain age-strengthened aluminum-lithium alloy with excellent mechanical properties, and the prepared aluminum alloy has superior room temperature tensile strength and elongation Comprehensive mechanical properties such as rate and elastic modulus.

Beneficial effect

The invention adopts smelting casting and deformation heat treatment methods, based on Al-Cu-Li-Mg series alloys, by adjusting the content and ratio of main elements (Li, Cu), trace strengthening elements (Mg, Ag, Zn) and crystal grain control The content of elements (Zr, Mn, Sc), multi-stage homogenization annealing process, gradual heating and solid solution process, cold rolling deformation and aging treatment process conditions, to obtain an age-strengthened aluminum-lithium alloy with excellent mechanical properties. The similar aluminum alloy has excellent room temperature tensile strength, elongation, elastic modulus and other comprehensive mechanical properties. The strengthening phase of the alloy is the aging precipitation phase [T ₁ (Al ₂ CuLi), δ′(Al ₃ Li), θ′(Al ₂ Cu) and S′(A1 ₂ CuMg)] and the dispersed phase (Al ₃ Zr, Al ₂₀ Cu ₂ Mn ₃ , Al ₃ Sc). The combined effect of the aging precipitated phase and the dispersed phase can ensure that the material has high room temperature tensile strength, elongation and elastic modulus, thereby obtaining excellent comprehensive properties.

Description of the drawings

Figure 1 is a typical microstructure of the alloy of the present invention.

Figure 2 is a typical tensile stress-strain curve of the alloy of the present invention at room temperature.

The best mode of the invention

Type here a paragraph describing the best mode of the invention.

Embodiments of the invention

Comparative example 1 .

The composition and weight percentage of the alloy are 2%Li-3%Cu-3%Mg-0.25%Zr-5%Zn, and the mass fraction ratio of Cu/Li is 1.5. In the atmospheric environment, the pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure lithium are melted in a melting furnace, degassed and slag removed by argon, and then cast in a static state. The ingot was directly annealed in a single stage at 500℃ for 48h. The annealed ingot is then extruded into a sheet at 430°C with an extrusion ratio of 10, and the sheet is single-stage solutionized at 520°C for 1 hour, cooled to room temperature in water, and the solution quenched material is aged at 160°C for 36 hours to obtain a finished product. Its performance is shown in Table 1.

Comparative example 2 .

The alloy composition and its weight percentage are 1.3%Li-5.85%Cu-0.4%Mg-0.4%Ag-0.14%Zr, and the mass fraction ratio of Cu/Li is 3.6. In a vacuum environment, the pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure lithium are melted in a smelting furnace, and then statically cast to form. The ingot was single-stage homogenized annealing at 490℃ for 36h. The annealed ingot is then extruded into a sheet at 420°C with an extrusion ratio of 10. The sheet is single-stage solutionized at 520°C for 60 minutes, cooled to room temperature in water, and the solution quenched material is pre-stretched by 3%, and then at 160°C The aging treatment is 36h to obtain the finished product. Its performance is shown in Table 1.

Comparative example 3 .

The alloy composition and its weight percentage are 1%Li-4%Cu-0.5%Mg-0.15%Zr-0.5%Ag-0.3Mn-0.8Zn, and the mass fraction ratio of Cu/Li is 4. In the atmospheric environment, put pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver into a melting furnace in order to melt, and sprinkle a covering agent on the surface; then press pure lithium into the above In the molten alloy melt, argon gas is used for degassing and slagging and refining, and standing for casting. The ingot was single-stage homogenized annealing at 500℃ for 30h. The annealed ingot is then extruded into a sheet at 430°C with an extrusion ratio of 10, and the sheet is single-stage solid solution at 530°C for 60 minutes, cooled to room temperature in water, and the solution quenched material is pre-stretched and deformed by 3%, and aged at 160°C Process for 32h to obtain the finished product. Its performance is shown in Table 1.

Example 1 .

The alloy composition and its weight percentage are 0.8%Li-4.3%Cu-0.3%Mg-0.1%Zr-0.1%Mn-0.81%Zn-0.1%Ag-0.09Sc, and the mass fraction ratio of Cu/Li is 5.4. The preparation method is as follows: in an atmospheric environment, put pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver into a melting furnace to melt, and sprinkle a covering agent on the surface; Lithium is pressed into the above-mentioned molten alloy melt, argon gas is used for degassing and slag refining, and it is statically cast and formed. The ingot is subjected to multi-stage homogenization annealing treatment, the annealing process is: 400℃ for 5 hours, then heated to 450℃ for 10 hours, and then heated to 490℃ for 24 hours. The annealed sample was extruded into a sheet at an extrusion ratio of 5 at 430°C. The hot-extruded sheet alloy is gradually heated for solution and quenching. The solution process is: heating to 400°C for 1 hour, then heating to 470°C for 1 hour, and then heating to 510°C for 1 hour. After the solution treatment, the water is cooled to room temperature. The material after gradually heating up solution and quenching is deformed by cold rolling, and the deformation is 3%. The cold-rolled and deformed samples are subjected to aging treatment at an aging temperature of 130°C for 50 hours to obtain a finished product. Its performance is shown in Table 1.

Example 2 .

The alloy composition and its weight percentage are 1.2%Li-5.2%Cu-0.6%Mg-0.2%Zr-0.2%Mn-0.5%Zn-0.5%Ag-0.1Sc, and the mass fraction ratio of Cu/Li is 4.3. The preparation method is as follows: in an atmospheric environment, put pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver into a melting furnace to melt, and sprinkle a covering agent on the surface; Lithium is pressed into the above-mentioned molten alloy melt, argon gas is used for degassing and slag refining, and it is statically cast and formed. The ingot is subjected to multi-stage homogenization annealing treatment. The annealing process is: heat preservation at 420°C for 1 hour, then heat to 480°C for 5 hours, and then heat to 510°C for 12 hours. The annealed sample was extruded at 460°C with an extrusion ratio of 20 into a sheet. The hot-extruded sheet alloy is gradually heated for solution and quenching. The solution process is: heating to 450°C for 1.5h, then heating to 490°C for 0.5h, and then heating to 530°C for 0.5h. After the solution treatment, the water is cooled to room temperature. The material after gradually heating up solution and quenching is cold-rolled and deformed, and the deformation is 10%. The cold-rolled and deformed samples are subjected to aging treatment at a temperature of 170°C for 10 hours to obtain a finished product. Its performance is shown in Table 1.

Example 3 .

The alloy composition and its weight percentage are 1.0%Li-4.5%Cu-0.7%Mg-0.2%Zr-0.2%Mn-1.5%Zn-0.5%Ag-0.3Sc, and the mass fraction ratio of Cu/Li is 4.5. The preparation method is as follows: under vacuum, the pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver are melted in a smelting furnace, and then statically cast to form. The ingot is subjected to multi-stage homogenization annealing treatment, the annealing process is: 380°C for 5 hours, then heated to 460°C for 7.5 hours, and then heated to 500°C for 24 hours. The annealed sample was extruded into a sheet at an extrusion ratio of 12.5 at 440°C. The hot-extruded sheet alloy is gradually heated for solution and quenching. The solution process is: heating to 425°C for 2 hours, then heating to 480°C for 1 hour, and then heating to 530°C for 1 hour. After the solution treatment, the water is cooled to room temperature. The material after being gradually heated to solid solution and quenched is deformed by cold rolling, and the deformation is 15%. The cold-rolled and deformed samples are subjected to aging treatment at an aging temperature of 160°C for 35 hours to obtain a finished product. Its performance is shown in Table 1.

Example 4 .

The composition and weight percentage of the alloy are 1.0%Li-5.2%Cu-0.45%Mg-0.15%Zr-0.15%Mn-0.9%Zn-0.4%Ag-0.15Sc, and the mass fraction ratio of Cu/Li is 5.2. The preparation method is as follows: under vacuum, the pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver are melted in a smelting furnace, and then statically cast to form. The ingot is subjected to multi-stage homogenization annealing treatment, the annealing process is: 400℃ for 3h, then heated to 450℃ for 5h, and then heated to 500℃ for 24h. The annealed sample was extruded into a sheet at 450°C with an extrusion ratio of 10. The hot-extruded sheet alloy is gradually heated for solution and quenching. The solution process is: heating to 430°C for 1 hour, then heating to 470°C for 0.7 hours, and then heating to 530°C for 0.7 hours. After the solution treatment, the water is cooled to room temperature. The material after gradually heating up solution and quenching is cold-rolled and deformed, and the deformation is 10%. The cold-rolled and deformed samples are subjected to aging treatment at an aging temperature of 150°C for 40 hours to obtain a finished product. Its performance is shown in Table 1.

Example 5 .

The alloy composition and its weight percentage are 0.9%Li-4.8%Cu-0.5%Mg-0.15%Zr-0.15%Mn-0.9%Zn-0.3%Ag-0.15Sc, and the mass fraction ratio of Cu/Li is 5.3. The preparation method is as follows: under vacuum, the pure aluminum, aluminum-copper intermediate alloy, aluminum-zirconium intermediate alloy, aluminum-scandium intermediate alloy pure zinc, pure magnesium, and pure silver are melted in a smelting furnace, and then statically cast to form. The ingot is subjected to multi-level homogenization annealing treatment, the annealing process is: 400℃ for 5h, then heated to 480℃ for 5h, and then heated to 510℃ for 12h. The annealed sample was extruded into a sheet at 450°C with an extrusion ratio of 10. The hot-extruded sheet alloy is gradually heated for solution and quenching. The solution process is: heating to 450°C for 1.5h, then heating to 490°C for 0.5h, and then heating to 530°C for 0.5h. After the solution treatment, the water is cooled to room temperature. The material after gradually heating up solution and quenching is cold-rolled and deformed, and the deformation is 10%. The cold-rolled and deformed samples are subjected to aging treatment at an aging temperature of 150°C for 40 hours to obtain a finished product. Its performance is shown in Table 1.

Example 6 .

The alloy composition and its weight percentage are 0.87%Li-4.6%Cu-0.6%Mg-0.2%Zr-0.2%Mn-1.0%Zn-0.3%Ag-0.09Sc, and the mass fraction ratio of Cu/Li is 5.3. The preparation method is as follows: under vacuum, the pure aluminum, aluminum-copper intermediate alloy, aluminum-zirconium intermediate alloy, aluminum-scandium intermediate alloy pure zinc, pure magnesium, and pure silver are melted in a smelting furnace, and then statically cast to form. The ingot is subjected to multi-level homogenization annealing treatment, the annealing process is: 400℃ for 5h, then heated to 480℃ for 5h, and then heated to 510℃ for 12h. The annealed sample was extruded into a sheet at 450°C with an extrusion ratio of 10. The hot-extruded sheet alloy is gradually heated for solution and quenching. The solution process is: heating to 450°C for 1.5h, then heating to 490°C for 0.5h, and then heating to 530°C for 0.5h. After the solution treatment, the water is cooled to room temperature. The material after gradually heating up the solution and quenching is cold-rolled and deformed, and the deformation is 20%. The cold-rolled and deformed samples are subjected to aging treatment at an aging temperature of 160°C for 30 hours to obtain a finished product. Its performance is shown in Table 1.

Example 7

The alloy composition and its weight percentage are 1%Li-4.3%Cu-0.5%Mg-0.15%Zr-0.15%Mn-0.81%Zn-0.3%Ag-0.09Sc, and the mass fraction ratio of Cu/Li is 4.3. The preparation method is as follows: in an atmospheric environment, put pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver into a melting furnace to melt, and sprinkle a covering agent on the surface; Lithium is pressed into the above-mentioned molten alloy melt, argon gas is used for degassing and slag refining, and it is statically cast and formed. The ingot is subjected to multi-stage homogenization annealing treatment. The annealing process is: heat preservation at 420°C for 3 hours, then heating to 470°C for 8 hours, and then heating to 500°C for 24 hours. The annealed sample was extruded into a sheet at 450°C with an extrusion ratio of 10. The hot-extruded sheet alloy is gradually heated for solution and quenching. The solution process is: heating to 450°C for 1h, then heating to 500°C for 0.5h, and then heating to 530°C for 0.5h. After the solution treatment, the water is cooled to room temperature. The material after gradually heating up solution and quenching is cold-rolled and deformed, and the deformation is 10%. The cold-rolled and deformed samples are subjected to aging treatment at an aging temperature of 160°C for 36 hours to obtain a finished product. Its performance is shown in Table 1.

Example 8

The alloy composition and its weight percentage are 0.8%Li-5.2%Cu-0.4%Mg-0.1%Zr-0.1%Mn-1.2%Zn-0.3%Ag-0.1Sc, and the mass fraction ratio of Cu/Li is 6.5. The preparation method is as follows: in an atmospheric environment, put pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver into a melting furnace to melt, and sprinkle a covering agent on the surface; Lithium is pressed into the above-mentioned molten alloy melt, argon gas is used for degassing and slag refining, and it is statically cast and formed. The ingot is subjected to multi-stage homogenization annealing treatment. The annealing process is: heat preservation at 420°C for 3 hours, then heating to 470°C for 8 hours, and then heating to 500°C for 24 hours. The annealed sample was extruded into a sheet at 450°C with an extrusion ratio of 10. The hot-extruded sheet alloy is gradually heated for solution and quenching. The solution process is: heating to 450°C for 1h, then heating to 500°C for 0.5h, and then heating to 530°C for 0.5h. After the solution treatment, the water is cooled to room temperature. The material after gradually heating up solution and quenching is cold-rolled and deformed, and the deformation is 10%. The cold-rolled and deformed samples are subjected to aging treatment at an aging temperature of 160°C for 36 hours to obtain a finished product. Its performance is shown in Table 1.

Example 9

The composition and weight percentage of the alloy are 1.0%Li-5.2%Cu-0.45%Mg-0.1%Zr-0.1%Mn-1.0%Zn-0.3%Ag-0.15Sc, and the mass fraction ratio of Cu/Li is 5.4. The preparation method is as follows: in an atmospheric environment, put pure aluminum, aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver into a melting furnace to melt, and sprinkle a covering agent on the surface; Lithium is pressed into the above-mentioned molten alloy melt, argon gas is used for degassing and slag refining, and it is statically cast and formed. The ingot is subjected to multi-stage homogenization annealing treatment. The annealing process is: heat preservation at 420°C for 3 hours, then heating to 470°C for 8 hours, and then heating to 500°C for 24 hours. The annealed sample was extruded into a sheet at 450°C with an extrusion ratio of 10. The hot-extruded sheet alloy is gradually heated for solution and quenching. The solution process is: heating to 450°C for 1h, then heating to 500°C for 0.5h, and then heating to 530°C for 0.5h. After the solution treatment, the water is cooled to room temperature. The material after gradually heating up solution and quenching is cold-rolled and deformed, and the deformation is 10%. The cold-rolled and deformed samples are subjected to aging treatment at an aging temperature of 160°C for 36 hours to obtain a finished product. Its performance is shown in Table 1.

Table 1 Room temperature properties of the alloy of the invention.

.

In Table 1: the tensile strength of the product obtained in Comparative Example 1 is 520MPa, the yield strength is 485MPa, the elongation is 7.8%, and the elastic modulus is 75GPa; the tensile strength of the product obtained in Comparative Example 2 is 626MPa, the yield strength It is 565MPa, the elongation is 6.7%, and the elastic modulus is 76 GPa; the tensile strength of the product obtained in Comparative Example 3 is 625 MPa, the yield strength is 558 MPa, the elongation is 7.0%, and the elastic modulus is 75 GPa; Example 1 The tensile strength of the product obtained was 635MPa, the yield strength was 552MPa, the elongation was 10.9%, and the modulus of elasticity was 76GPa; the product obtained in Example 2 had the tensile strength of 642MPa, the yield strength of 602MPa, and the elongation of 11.5% The elastic modulus is 81 GPa; the tensile strength of the product obtained in Example 3 is 662 MPa, the yield strength is 621 MPa, the elongation is 9.4%, and the elastic modulus is 81 GPa; the tensile strength of the product obtained in Example 4 is 660 MPa, yielding The strength is 621 MPa, the elongation is 9.5%, and the elastic modulus is 79 GPa; the tensile strength of the product obtained in Example 5 is 652 MPa, the yield strength is 611 MPa, the elongation is 10.2%, and the elastic modulus is 78 GPa; Example 6 The tensile strength of the product obtained is 704MPa, the yield strength is 672MPa, the elongation is 12.5%, and the elastic modulus is 78GPa; the product obtained in Example 7 has a tensile strength of 701MPa, yield strength of 632MPa, and elongation of 9.5% The elastic modulus is 79 GPa; the tensile strength of the product obtained in Example 8 is 604 MPa, the yield strength is 573 MPa, the elongation is 8.5%, and the elastic modulus is 77 GPa; the tensile strength of the product obtained in Example 9 is 685 MPa, yielding The strength is 613MPa, the elongation is 8.3%, and the elastic modulus is 79GPa.

Comparing the performance parameter values of the example and the comparative example, it can be seen that the comprehensive properties such as tensile strength, yield strength, elongation and elastic modulus of the ultra-high-strength aluminum-lithium alloy prepared by the present invention are significantly higher than those of the comparative example alloy. . Through the optimized schemes of the present invention (such as Examples 6, 7, and 9), the performance of the obtained product is far superior to that of the comparative example and other examples.

Claims

An ultra-high-strength aluminum-lithium alloy, characterized in that it includes the following components in mass percentage: Cu 4.3-5.2%, Li 0.8-1.2%, Mg 0.3-0.7%, Ag 0.1-0.5%, Zn 0.81-1.5% , Mn 0.1～0.2%, Zr 0.1～0.2%, Sc 0.09～0.3%, Cu/Li mass fraction ratio 4.3～6.5, the balance is Al.
The ultra-high-strength aluminum-lithium alloy according to claim 1, characterized in that it comprises the following components in mass percentage: Cu 4.86%, Li 0.87%, Mg 0.5%, Ag 0.3%, Zn 1.0%, Mn 0.2 %, Zr 0.15%, Sc 0.09%, the balance is Al.
The ultra-high-strength aluminum-lithium alloy according to claim 1, characterized in that it comprises the following components in mass percentage: Cu 4.3%, Li 1%, Mg 0.5%, Ag 0.3%, Zn 0.81%, Mn 0.15%, Zr 0.15%, Sc 0.09%, the balance is Al.
The ultra-high-strength aluminum-lithium alloy according to claim 1, characterized in that it comprises the following components in mass percentage: Cu 5.2%, Li 1%, Mg 0.45%, Ag 0.3%, Zn 1.0%, Mn 0.15%, Zr 0.1%, Sc 0.15%, the balance is Al.
The method for preparing an ultra-high-strength aluminum-lithium alloy according to any one of claims 1-4, characterized in that it comprises the following steps:

According to the designed distribution ratio of aluminum alloy components, weigh each component, and use atmospheric melting or vacuum melting to combine aluminum, lithium, aluminum-copper master alloy, magnesium, silver, aluminum-zirconium master alloy, aluminum-manganese master alloy, aluminum-scandium master alloy and Zinc is melted, degassed and slag removed, cast into ingots, and then the ingots are subjected to multi-level homogenization treatment, hot extrusion deformation, gradual heating and solid solution, cold rolling deformation and timely treatment.
The method according to claim 5, wherein:

The casted ultra-high-strength aluminum-lithium alloy ingot undergoes multi-stage homogenization annealing treatment to obtain a homogenized annealed ingot; the annealing process is: heating to 380~420℃ for 1~5h, and then heating to 450~480℃ for 5 ~10h, then heat to 490～510℃ for 12～24h;

The homogenized annealed ingot is hot-extruded into a plate, the extrusion temperature is 430～460℃, and the extrusion ratio is 5～20;

The hot-extruded sheet alloy is gradually heated to solid solution and quenched. The solid solution process is: heating to 400~450℃ for 1~2h, then heating to 470~490℃ for 0.5~1h, and then heating to 510~530℃ for insulation 0.5～1h. After the solution treatment, cool the water to room temperature;

The material after gradual heating and solid solution and quenching undergoes cold rolling deformation, the deformation amount is 3-20%;

The samples after cold rolling are subjected to aging treatment, the aging temperature is 130～170℃, and the time is 10～50h.
The method according to claim 5, wherein the designed alloy includes the following components in mass percentage: Cu 4.86%, Li 0.87%, Mg 0.5%, Ag 0.3%, Zn 1.0%, Mn 0.2%, Zr 0.15%, Sc 0.09%, the balance is Al; the preparation method is: under vacuum, the pure aluminum , Aluminum-copper master alloy, aluminum-zirconium master alloy, aluminum-scandium master alloy, pure zinc, pure magnesium, and pure silver are melted in a smelting furnace, and statically cast to form; the ingot undergoes multi-level homogenization annealing treatment, the annealing process is: 400 ℃ for 5h, then heated to 480℃ for 5h, and then heated to 510℃ for 12h; the annealed sample is extruded at 450℃ with an extrusion ratio of 10 into plates; the hot-extruded plate alloy is gradually heated and quenched. The solution process is: heating to 450℃ for 1.5h, then heating to 490℃ for 0.5h, then heating to 530℃ for 0.5h; after solution treatment, water cooling to room temperature; then cold rolling and cold rolling The amount is 20%; the cold-rolled and deformed samples are subjected to aging treatment at an aging temperature of 160°C for 30 hours to obtain a finished product.
The method according to claim 5, wherein the designed alloy includes the following components in mass percentage: Cu 4.3%, Li 1%, Mg 0.5%, Ag 0.3%, Zn 0.81%, Mn 0.15%, Zr 0.15%, Sc 0.09%, the balance is Al; its preparation method is: in the atmospheric environment, the pure aluminum , Aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver are melted in a melting furnace, and a covering agent is sprinkled on the surface; then pure lithium is pressed into the molten alloy melt, using argon Refining by gas degassing and slagging, static casting and forming; the ingot undergoes multi-level homogenization annealing treatment, the annealing process is: 420℃ for 3h, then heated to 470℃ for 8h, and then heated to 500℃ for 24h; after annealing The sample is extruded into a sheet at 450°C with an extrusion ratio of 10; the hot-extruded sheet alloy undergoes gradual heating and solid solution and quenching treatment. The solution process is: heating to 450°C for 1 hour, then heating to 500°C for 0.5h, and then heating Incubate at 530°C for 0.5h; after solution treatment, cool to room temperature in water. Gradually heat up the solution and quench the material after cold rolling deformation, the deformation amount is 10%; the sample after cold rolling deformation is subjected to aging treatment, the aging temperature is 160℃, and the time is 36h, and the finished product is obtained.
The method according to claim 5, wherein the designed alloy includes the following components in mass percentage: Cu 5.2%, Li 1%, Mg 0.45%, Ag 0.3%, Zn 1.0%, Mn 0.15%, Zr 0.1%, Sc 0.15%, the balance is Al; its preparation method is: in the atmospheric environment, the pure aluminum , Aluminum-copper master alloy, aluminum-zirconium master alloy, pure zinc, pure magnesium, and pure silver are melted in a melting furnace, and a covering agent is sprinkled on the surface; then pure lithium is pressed into the molten alloy melt, using argon Refining by gas degassing and slagging, static casting and forming; the ingot undergoes multi-level homogenization annealing treatment, the annealing process is: 420℃ for 3h, then heated to 470℃ for 8h, and then heated to 500℃ for 24h; after annealing The sample is extruded into a sheet at 450°C with an extrusion ratio of 10; the hot-extruded sheet alloy undergoes gradual heating and solid solution and quenching treatment. The solution process is: heating to 450°C for 1 hour, then heating to 500°C for 0.5h, and then heating Incubate at 530°C for 0.5h. ; After the solution treatment is completed, cool to room temperature in water; gradually heat up the solution and quench the material to undergo cold rolling deformation, with a deformation amount of 10%; the samples after cold rolling deformation are subjected to aging treatment at an aging temperature of 160°C for 36 hours to obtain the finished product .