A novel process for preparing aerospace aluminum-lithium alloys containing refining agents and Al-Ca-In-V composite additives.

Abstract

This invention discloses a novel process for preparing aerospace-grade aluminum-lithium alloys containing refining agents and Al-Ca-In-V composite additives, belonging to the field of aerospace materials technology. This process, through the design of a multi-element alloy system, achieves a synergistic improvement in strength, toughness, and corrosion resistance via vacuum melting, semi-continuous casting, homogenization, triaxial forging, solution treatment, and two-stage aging. It is applicable to key structural components such as aircraft fuselages and wings, demonstrating significant economic benefits and application value.

Description

Technical Field

[0001] This invention belongs to the field of aerospace materials technology, specifically relating to a novel process for preparing aerospace aluminum-lithium alloys containing refining agents and Al-Ca-In-V composite additives. Background Technology

[0002] Aluminum-lithium alloys have become core materials for weight reduction and efficiency improvement in the aerospace field due to their high specific strength and low density (adding 1% Li can reduce density by 3% and increase stiffness by 6%). Traditional aerospace aluminum-lithium alloys (such as the 2099 and 2195 series) are mainly alloyed through Al-Cu-Li-Mg systems. Although they can achieve tensile strengths of 500-550 MPa, they suffer from defects such as difficulty in balancing toughness and strength and poor thermal stability.

[0003] Existing patents, such as CN112375829A, refine grain size by adding Sc, but Sc is expensive (approximately 3000 RMB / kg), limiting its large-scale application. Patent CN108642275B introduces Akg to improve age hardening, but its improvement on corrosion resistance is limited. Therefore, developing a novel aluminum-lithium alloy preparation process that is low-cost and combines high strength, high toughness, and excellent corrosion resistance is of great significance to the development of the aerospace industry. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a novel aerospace aluminum-lithium alloy preparation process containing refining agents and Al-Ca-In-V composite additives. Through the synergistic effect of Ca, In and V, a balance between strength, toughness, corrosion resistance and lightweight is achieved while reducing costs.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A novel process for preparing aerospace-grade aluminum-lithium alloys, comprising refining agents and Al-Ca-In-V composite additives, characterized by the following steps:

[0007] (1) Raw material ratio: Weigh out Li, Ca, In, V, Cu, Mg, Zn, Zr, and the rest is Al;

[0008] (2) Vacuum melting: Heat the aluminum ingot to melt, add Cu, Mg, Zn, Zr and refining agent in sequence, keep warm, then heat up again, add Li-Ca master alloy, In particles and V powder, and stir.

[0009] (3) Semi-continuous casting: The melt is horizontally continuously cast at a certain speed at high temperature to obtain an ingot;

[0010] (4) Homogenization treatment: The ingot is kept warm and then cooled to room temperature in the furnace;

[0011] (5) Hot deformation: The ingot is heated and subjected to three-dimensional forging;

[0012] (6) Solution treatment: heat preservation of forging billet, water quenching and cooling;

[0013] (7) Aging treatment: Keep warm at a suitable temperature, continue to keep warm after heating up, and air cool to room temperature to obtain a new type of aviation aluminum-lithium alloy.

[0014] Further, the mass percentage of each raw material in step (1) is Li 1.5-2.0%, Ca 0.1-0.2%, In 0.05-0.1%, V 0.1-0.15%, Cu 2.8-3.2%, Mg 0.7-0.9%, Zn 0.1-0.3%, and Zr 0.08-0.12%.

[0015] Further, in step (2), the melting temperature is 700-720℃, and the holding temperature is 30-60min; the temperature is raised to 740-760℃, Li-Ca master alloy, In particles, and V powder are added, stirred for 15-25min, and the vacuum degree is maintained at 0.001-0.0002Pa; the preparation method of the Li-Ca master alloy is as follows: under argon protection, Li and Ca are melted at 650-680℃ in a mass ratio of 1.5-2.0:0.1-0.2, held for 40-60min, and then cast.

[0016] Further, the refining agent in step (2) is 5-10 parts by weight, and the preparation method is as follows, according to parts by weight:

[0017] S1. Preparation of three-dimensional network polysilazane: 7.0-9.0 parts by mass of polydimethyldiphenylsiloxane, 1.5-2.0 parts of triethylenetetramine, 8.4-13.5 parts of xylene and 0.1-0.3 parts of stannous octoate are mixed and reacted at 150-180℃ for 4-6 hours under nitrogen protection.

[0018] S2. Preparation of [Pr(en)2F3]+ coordination polymer: Mix 0.7-1.0 parts of praseodymium fluoride, 1.5-2.0 parts of triethylenetetramine, 100-180 parts of ethanol, and 0.05-0.1 parts of trifluoromethanesulfonic acid, and reflux for 2-4 hours.

[0019] S3. Mixing reaction: The products of S1 and S2 are mixed with vanadium nitride and aluminum powder to obtain an aerospace aluminum-lithium alloy refining agent.

[0020] Furthermore, the refining agent contains 0.4-0.6 parts of vanadium nitride and 8.0-10.0 parts of aluminum powder.

[0021] Further, in step (3), the melt is horizontally continuously cast at a speed of 80-120 mm / min at 720-740℃, the crystallizer water temperature is 20-30℃, and the cooling intensity is 13-16℃ / mm, to obtain an ingot with a diameter of φ240-260mm.

[0022] Furthermore, in step (4), the ingot is held at 450-470℃ for 10-14 hours, cooled in the furnace to 290-310℃, and then air-cooled to room temperature.

[0023] Further, in step (5), the ingot is heated to 410-430°C and subjected to three-dimensional forging. The reduction rate is 30-35% in the first pass, 25-30% in the second pass, 20-25% in the third pass, and the final forging temperature is 380°C.

[0024] Furthermore, in step (6), the forging billet is held at 520-540℃ for 1-2 hours and then water-quenched at a cooling rate of 150-200℃ / s.

[0025] Further, in step (7), the temperature is first kept at 110-130℃ for 5-7 hours, then heated to 150-170℃ and kept at 11-13 hours, and then air-cooled to room temperature to obtain a new type of aviation aluminum-lithium alloy.

[0026] The reaction mechanism of the refining agent:

[0027] The silicon-oxygen bonds in polydimethyldiphenylsiloxane undergo a ring-opening condensation reaction with the amino groups of triethylenetetramine, forming a three-dimensional network of polysilazane under nitrogen protection and at 180°C. This structure provides a stable skeletal support for aluminum-lithium alloys. Praseodymium fluoride reacts with triethylenetetramine in an ethanol reflux environment, where praseodymium ions form coordination bonds with the amino groups to generate a [Pr(en)₂F₃]⁺ coordination polymer, which can effectively capture impurity ions in the alloy. Vanadium nitride and aluminum powder are dispersed under high temperature and vacuum, and synergistically work with the above two products to remove gases and inclusions from the alloy through physical encapsulation and chemical adsorption.

[0028] Technical effects:

[0029] Synergistic effect of composite addition: Ca refines grains, In improves corrosion resistance, and V enhances thermal stability. The synergistic effect of the three makes the overall performance better than that of single element addition.

[0030] As a refining agent for aerospace aluminum-lithium alloys, it can significantly reduce the gas content in the alloy and improve the mechanical properties of the alloy. Moreover, the refining agent has good compatibility with the alloy and leaves no harmful residues, meeting the stringent requirements of the aerospace field for high-performance materials. Detailed Implementation

[0031] Tensile strength, yield strength, and elongation testing: Referring to kgB / T 228.1-2021 "Metallic materials, tensile testing—Part 1: Tests at room temperature," standard tensile specimens (circular cross-section specimens, 5mm diameter, 25mm gauge length; or rectangular cross-section specimens, 3mm thickness, 50mm gauge length; ensuring the surface roughness Ra of the parallel sections of the specimen is ≤1.6μm) were cut from the prepared aerospace aluminum-lithium alloy billet. Using a 0.5-grade precision universal testing machine, the room temperature (23±5℃) and tensile rate (2mm / min) were set to conduct axial tensile tests. The stress-strain curve was recorded in real time, and the yield strength (lower yield strength; if no obvious yield is observed, the specified non-proportional elongation strength R) was read from the curve. p0.2 The tensile strength is calculated based on the change in the length of the gauge length after the specimen breaks (elongation = (gauge length after break - original gauge length) / original gauge length × 100%). Five specimens are tested in parallel for each performance parameter, and the average value is taken after removing outliers. The requirements are tensile strength ≥ 580 MPa, yield strength ≥ 510 MPa, and elongation ≥ 12%.

[0032] Density testing: According to the relevant requirements for density testing in GB / T 2975-2018 "Sampling Location and Sample Preparation for Mechanical Property Testing of Steel and Steel Products", the water displacement method (Archimedes' principle) is used. An alloy sample (approximately 10mm × 10mm × 10mm in size, with no surface defects such as pores or cracks) is selected. The mass (m1) of the sample in air is measured using an analytical balance (accuracy 0.0001kg). The sample is then completely immersed in deionized water at 25±2℃, and the mass (m2) of the sample in water is measured. The density is calculated using the formula ρ = ρwater × m1 / (m1 - m2) (where ρwater is the density of deionized water at 25℃, taken as 0.9970 kg / cm³). 3 The test was conducted in three parallel trials, and the average value was taken. The density was required to be ≤2.65 kg / cm³. 3 .

[0033] The present invention will be described in detail below with reference to specific embodiments:

[0034] Example 1

[0035] A novel process for preparing aerospace-grade aluminum-lithium alloys, including refining agents and Al-Ca-In-V composite additives, comprises the following steps:

[0036] (1) Raw material ratio: Weigh 1.5kg Li, 0.1kg Ca, 0.05kg In, 0.1kg V, 2.8kg Cu, 0.7kg Mg, 0.1kg Zn, 0.08kg Zr, and the remainder is Al, with a total mass of 100kg.

[0037] (2) Vacuum melting: Heat the aluminum ingot to 700℃ to melt it, and add Cu, Mg, Zn, Zr and 5kg of refining agent in sequence, and keep it at the temperature for 30min; raise the temperature to 740℃, add Li-Ca master alloy, In particles and V powder, stir for 15min, and maintain the vacuum degree at 0.001Pa.

[0038] The preparation method of Li-Ca master alloy is as follows: 1.5 kg Li and 0.1 kg Ca are melted at 650 °C under argon protection, held at the temperature for 40 min, and then cast into shape.

[0039] The refining agent is prepared by:

[0040] S1. Preparation of three-dimensional network polysilazane: 7.0 kg of polydimethyldiphenylsiloxane, 1.5 kg of triethylenetetramine, 8.4 kg of xylene and 0.1 kg of stannous octoate were mixed and reacted at 150 °C for 4 hours under nitrogen protection;

[0041] S2. Preparation of [Pr(en)2F3]+ coordination polymer: Mix 0.7 kg praseodymium fluoride, 1.5 kg triethylenetetramine, 100 kg ethanol, and 0.05 kg trifluoromethanesulfonic acid, and reflux for 2 hours;

[0042] S3. Mixing reaction: The products of S1 and S2 are mixed with 0.4 kg of vanadium nitride and 8.0 kg of aluminum powder to obtain an aerospace aluminum-lithium alloy refining agent.

[0043] (3) Semi-continuous casting: The melt is horizontally continuously cast at 720℃ at a speed of 80mm / min, the crystallizer water temperature is 20℃, the cooling intensity is 13℃ / mm, and a φ240mm ingot is obtained.

[0044] (4) Homogenization treatment: The ingot is kept at 450℃ for 10 hours, cooled to 290℃ with the furnace, and then air-cooled to room temperature.

[0045] (5) Hot deformation: The ingot is heated to 410°C and forged in three directions. The reduction rate is 30% in the first pass, 25% in the second pass, and 20% in the third pass. The final forging temperature is 380°C.

[0046] (6) Solution treatment: The forging billet is held at 520℃ for 1 hour and then water-quenched at a rate of 150℃ / s.

[0047] (7) Aging treatment: Hold at 110℃ for 5 hours, raise the temperature to 150℃ and hold for 11 hours, then air cool to room temperature to obtain a new type of aviation aluminum-lithium alloy.

[0048] Example 2

[0049] A novel process for preparing aerospace-grade aluminum-lithium alloys, including refining agents and Al-Ca-In-V composite additives, comprises the following steps:

[0050] (1) Raw material ratio: By mass percentage, Li 1.75kg, Ca 0.15kg, In 0.08kg, V 0.12kg, Cu 3.0kg%, Mg 0.8kg, Zn 0.2kg, Zr 0.1kg, the remainder being Al and unavoidable impurities, with a total mass of 100kg;

[0051] (2) Vacuum melting: Heat the aluminum ingot to 710℃ to melt it, and add Cu, Mg, Zn, Zr and 8kg of refining agent in sequence, and keep it at the temperature for 40min; raise the temperature to 750℃, add Li-Ca master alloy, In particles and V powder, stir for 20min, and maintain the vacuum degree at 0.002Pa.

[0052] The preparation method of Li-Ca master alloy is as follows: 1.75 kg Li and 0.15 kg Ca are melted at 660 °C under argon protection, held at the temperature for 50 min, and then cast into shape.

[0053] The refining agent is prepared by:

[0054] S1. Preparation of three-dimensional network polysilazane: 8 kg of polydimethyldiphenylsiloxane, 1.8 kg of triethylenetetramine, 10 kg of xylene and 0.2 kg of stannous octoate were mixed and reacted at 160 °C for 5 hours under nitrogen protection;

[0055] S2. Preparation of [Pr(en)2F3]+ coordination polymer: Mix 0.8 kg praseodymium fluoride, 1.7 kg triethylenetetramine, 150 kg ethanol, and 0.08 kg trifluoromethanesulfonic acid, and reflux for 3 hours;

[0056] S3. Mixing reaction: Mix the S1 product, the S2 product with 0.5 kg vanadium nitride and 9 kg aluminum powder to obtain an aerospace aluminum-lithium alloy refining agent.

[0057] (3) Semi-continuous casting: The melt is horizontally continuously cast at 730℃ at a speed of 100mm / min, the crystallizer water temperature is 25℃, the cooling intensity is 15℃ / mm, and a φ250mm ingot is obtained.

[0058] (4) Homogenization treatment: The ingot is kept at 460℃ for 12 hours, cooled to 300℃ with the furnace, and then air-cooled to room temperature.

[0059] (5) Hot deformation: The ingot is heated to 420°C and forged in three directions. The reduction rate is 32% in the first pass, 28% in the second pass, and 22% in the third pass. The final forging temperature is 380°C.

[0060] (6) Solution treatment: The forging billet is held at 530℃ for 1.5h and then water-quenched at a rate of 180℃ / s.

[0061] (7) Aging treatment: heat at 120℃ for 6 hours, heat up to 160℃ and heat for 12 hours, then air cool to room temperature to obtain a new type of aviation aluminum-lithium alloy.

[0062] Example 3

[0063] A novel process for preparing aerospace-grade aluminum-lithium alloys, including refining agents and Al-Ca-In-V composite additives, comprises the following steps:

[0064] (1) Raw material ratio: By mass percentage, mix 2.0 kg of Li, 0.2 kg of Ca, 0.1 kg of In, 0.15 kg of V, 3.2 kg of Cu, 0.9 kg of Mg, 0.3 kg of Zn, and 0.12 kg of Zr, with the remainder being Al and unavoidable impurities, for a total mass of 100 kg;

[0065] (2) Vacuum melting: Heat the aluminum ingot to 720℃ to melt it, and add Cu, Mg, Zn, Zr and 10kg of refining agent in sequence, and keep it at the temperature for 60min; raise the temperature to 760℃, add Li-Ca master alloy, In particles and V powder, stir for 25min, and maintain the vacuum degree at 0.0002Pa; The preparation method of Li-Ca master alloy is: melt 2.0kg Li and 0.2kg Ca at 680℃ under argon protection, keep it at the temperature for 60min and then cast it into shape.

[0066] The refining agent is prepared by:

[0067] S1. Preparation of three-dimensional network polysilazane: 9.0 kg of polydimethyldiphenylsiloxane, 2.0 kg of triethylenetetramine, 13.5 kg of xylene and 0.3 kg of stannous octoate were mixed and reacted at 180 °C for 6 hours under nitrogen protection;

[0068] S2. Preparation of [Pr(en)2F3]+ coordination polymer: Mix 1.0 kg praseodymium fluoride, 2.0 kg triethylenetetramine, 180 kg ethanol, and 0.1 kg trifluoromethanesulfonic acid, and reflux for 4 hours;

[0069] S3. Mixing reaction: The products of S1 and S2 are mixed with 0.6 kg of vanadium nitride and 10.0 kg of aluminum powder to obtain an aerospace aluminum-lithium alloy refining agent.

[0070] (3) Semi-continuous casting: The melt is horizontally continuously cast at 740℃ at a speed of 120mm / min, the crystallizer water temperature is 30℃, the cooling intensity is 16℃ / mm, and a φ260mm ingot is obtained.

[0071] (4) Homogenization treatment: The ingot is kept at 470℃ for 14 hours, cooled to 310℃ with the furnace, and then air-cooled to room temperature.

[0072] (5) Hot deformation: The ingot is heated to 430°C and forged in three directions. The reduction rate is 35% in the first pass, 30% in the second pass, and 25% in the third pass. The final forging temperature is 380°C.

[0073] (6) Solution treatment: The forging billet is held at 540℃ for 2 hours and then water-quenched at a rate of 200℃ / s.

[0074] (7) Aging treatment: heat at 130℃ for 7 hours, heat up to 170℃ and heat for 13 hours, then air cool to room temperature to obtain a new type of aviation aluminum-lithium alloy.

[0075] Comparative Example 1

[0076] A novel process for preparing aerospace-grade aluminum-lithium alloys, including refining agents and Al-Ca-In-V composite additives, comprises the following steps:

[0077] (1) Raw material ratio: Weigh 1.5kg of Li, 0.1kg of Ca, 0.05kg of In, 0.1kg of V, 2.8kg of Cu, 0.7kg of Mg, 0.1kg of Zn, 0.08kg of Zr, and the remainder is Al and unavoidable impurities, with a total mass of 100kg.

[0078] (2) Vacuum melting: Heat the aluminum ingot to 700℃ to melt it, add Cu, Mg, Zn and Zr in sequence, and keep it at the temperature for 30 min; raise the temperature to 740℃, add Li-Ca master alloy, In particles and V powder, stir for 15 min, and maintain the vacuum degree at 0.001 Pa.

[0079] The preparation method of Li-Ca master alloy is as follows: 1.5 kg Li and 0.1 kg Ca are melted at 650 °C under argon protection, held at the temperature for 40 min, and then cast into shape.

[0080] (3) Semi-continuous casting: The melt is horizontally continuously cast at 720℃ at a speed of 80mm / min, the crystallizer water temperature is 20℃, the cooling intensity is 13℃ / mm, and a φ240mm ingot is obtained.

[0081] (4) Homogenization treatment: The ingot is kept at 450℃ for 10 hours, cooled to 290℃ with the furnace, and then air-cooled to room temperature.

[0082] (5) Hot deformation: The ingot is heated to 410°C and forged in three directions. The reduction rate is 30% in the first pass, 25% in the second pass, and 20% in the third pass. The final forging temperature is 380°C.

[0083] (6) Solution treatment: The forging billet is held at 520℃ for 1 hour and then water-quenched at a rate of 150℃ / s.

[0084] (7) Aging treatment: Hold at 110℃ for 5 hours, raise the temperature to 150℃ and hold for 11 hours, then air cool to room temperature to obtain a new type of aviation aluminum-lithium alloy.

[0085] Comparative Example 2

[0086] A novel process for preparing aerospace-grade aluminum-lithium alloys, including refining agents and Al-Ca-In-V composite additives, comprises the following steps:

[0087] (1) Raw material ratio: Weigh 1.5kg of Li, 0.1kg of Ca, 0.05kg of In, 0.1kg of V, 2.8kg of Cu, 0.7kg of Mg, 0.1kg of Zn, 0.08kg of Zr, and the remainder is Al and unavoidable impurities, with a total mass of 100kg.

[0088] (2) Vacuum melting: Heat the aluminum ingot to 700℃ to melt it, and add Cu, Mg, Zn, Zr and 5kg of refining agent in sequence, and keep it at the temperature for 30min; raise the temperature to 740℃, add Li-Ca master alloy, In particles and V powder, stir for 15min, and maintain the vacuum degree at 0.001Pa.

[0089] The preparation method of Li-Ca master alloy is as follows: 1.5 kg Li and 0.1 kg Ca are melted at 650 °C under argon protection, held at the temperature for 40 min, and then cast into shape.

[0090] The refining agent is prepared by:

[0091] S1. Preparation of three-dimensional network polysilazane: 7.0 kg of polydimethyldiphenylsiloxane, 1.5 kg of triethylenetetramine, 8.4 kg of xylene and 0.1 kg of stannous octoate were mixed and reacted at 150 °C for 4 hours under nitrogen protection;

[0092] S2. Mixing reaction: The product of S1 is mixed with 0.4 kg of vanadium nitride and 8.0 kg of aluminum powder to obtain an aerospace aluminum-lithium alloy refining agent.

[0093] (3) Semi-continuous casting: The melt is horizontally continuously cast at 720℃ at a speed of 80mm / min, the crystallizer water temperature is 20℃, the cooling intensity is 13℃ / mm, and a φ240mm ingot is obtained.

[0094] (4) Homogenization treatment: The ingot is kept at 450℃ for 10 hours, cooled to 290℃ with the furnace, and then air-cooled to room temperature.

[0095] (5) Hot deformation: The ingot is heated to 410°C and forged in three directions. The reduction rate is 30% in the first pass, 25% in the second pass, and 20% in the third pass. The final forging temperature is 380°C.

[0096] (6) Solution treatment: The forging billet is held at 520℃ for 1 hour and then water-quenched at a rate of 150℃ / s.

[0097] (7) Aging treatment: Hold at 110℃ for 5 hours, raise the temperature to 150℃ and hold for 11 hours, then air cool to room temperature to obtain a new type of aviation aluminum-lithium alloy.

[0098] The detection results of the examples and comparative examples are shown in Table 1.

[0099] Table 1

[0100]

[0101] Compared to traditional aerospace aluminum-lithium alloy preparation processes, the aluminum-lithium alloy prepared by this invention through a novel Al-Ca-In-V composite addition process exhibits superior comprehensive properties, with a tensile strength ≥590MPa, elongation ≥13%, and density ≤2.65kg / cm³. 3 The addition of Ca refines the as-cast grains and inhibits δ-phase coarsening. In adsorption at grain boundaries reduces intergranular corrosion susceptibility and improves stress corrosion resistance. V forms VAl. 11 The dispersed phase improves the high-temperature stability of the alloy. The synergistic effect of the three components, combined with the two-stage aging treatment, balances strength and toughness while achieving lightweighting, making it suitable for the preparation of key structural components in the aerospace field.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A novel process for preparing aerospace-grade aluminum-lithium alloys containing refining agents and Al-Ca-In-V composite additives, characterized in that, Includes the following steps: Step (1) Raw material ratio: Weigh out Li, Ca, In, V, Cu, Mg, Zn, Zr, and the remainder is Al; Step (2) Vacuum melting: Heat the aluminum ingot to melt, add Cu, Mg, Zn, Zr and refining agent in sequence, keep warm, then heat up again, add Li-Ca master alloy, In particles and V powder, and stir; Step (3) Semi-continuous casting: The melt is horizontally continuously cast at a certain speed at a high temperature to obtain an ingot; Step (4) Homogenization treatment: Ingot heat preservation, followed by furnace cooling to room temperature; Step (5) Hot deformation: The ingot is heated and subjected to three-dimensional forging; Step (6) Solution treatment: heat preservation of forging billet, water quenching and cooling; Step (7) Aging treatment: Keep warm at a suitable temperature, raise the temperature and continue to keep warm, then air cool to room temperature to obtain a new type of aerospace aluminum-lithium alloy; The refining agent in step (2) is 5-10 parts by weight, and the preparation method is as follows, according to the mass parts: S1. Preparation of three-dimensional network polysilazane: 7.0-9.0 parts by mass of polydimethyldiphenylsiloxane, 1.5-2.0 parts of triethylenetetramine, 8.4-13.5 parts of xylene and 0.1-0.3 parts of stannous octoate are mixed and reacted at 150-180℃ for 4-6 hours under nitrogen protection; S2. Preparation of [Pr(en)2F3] + Coordination polymer: Mix 0.7-1.0 parts praseodymium fluoride, 1.5-2.0 parts triethylenetetramine, 100-180 parts ethanol, and 0.05-0.1 parts trifluoromethanesulfonic acid, and reflux for 2-4 hours; S3. Mixing reaction: The products of S1 and S2 are mixed with vanadium nitride and aluminum powder to obtain an aerospace aluminum-lithium alloy refining agent; The refining agent contains 0.4-0.6 parts vanadium nitride and 8.0-10.0 parts aluminum powder. The mass percentages of each raw material in step (1) are: Li 1.5-2.0%, Ca 0.1-0.2%, In 0.05-0.1%, V 0.1-0.15%, Cu 2.8-3.2%, Mg 0.7-0.9%, Zn 0.1-0.3%, and Zr 0.08-0.12%. The total mass fraction of all raw materials is 100.

2. The novel aerospace aluminum-lithium alloy preparation process containing refining agents and Al-Ca-In-V composite additives according to claim 1, characterized in that, In step (2), the melting temperature is 700-720℃, and the holding temperature is 30-60min; the temperature is raised to 740-760℃, Li-Ca master alloy, In particles, and V powder are added, and the mixture is stirred for 15-25min while maintaining a vacuum of 0.001-0.0002Pa; the preparation method of the Li-Ca master alloy is as follows: under argon protection, Li and Ca are melted at a mass ratio of 1.5-2.0:0.1-0.2 at 650-680℃, and the mixture is held for 40-60min before casting.

3. The novel aerospace aluminum-lithium alloy preparation process according to claim 1, comprising refining agents and Al-Ca-In-V composite additives, is characterized in that, In step (3), the melt is horizontally continuously cast at a speed of 80-120 mm / min at 720-740℃, the crystallizer water temperature is 20-30℃, and the cooling intensity is 13-16℃ / mm, to obtain an ingot with a diameter of φ240-260mm.

4. The novel aerospace aluminum-lithium alloy preparation process according to claim 1, comprising refining agent and Al-Ca-In-V composite additives, is characterized in that, In step (4), the ingot is held at 450-470℃ for 10-14 hours, cooled in the furnace to 290-310℃, and then air-cooled to room temperature.

5. The novel aerospace aluminum-lithium alloy preparation process according to claim 1, comprising refining agent and Al-Ca-In-V composite additives, characterized in that, In step (5), the ingot is heated to 410-430℃ and subjected to three-dimensional forging. The reduction rate is 30-35% in the first pass, 25-30% in the second pass, 20-25% in the third pass, and the final forging temperature is 380℃.

6. The novel aerospace aluminum-lithium alloy preparation process according to claim 1, comprising refining agent and Al-Ca-In-V composite additives, is characterized in that, In step (6), the forging billet is held at 520-540℃ for 1-2 hours and then water-quenched at a rate of 150-200℃ / s.

7. The novel aerospace aluminum-lithium alloy preparation process according to claim 1, comprising refining agent and Al-Ca-In-V composite additives, is characterized in that, In step (7), the temperature is first kept at 110-130℃ for 5-7 hours, then heated to 150-170℃ and kept for 11-13 hours, and then air-cooled to room temperature to obtain a new type of aviation aluminum-lithium alloy.

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