CN116673328B - Composite forming process and method for preparing near alpha high-temperature titanium alloy foil - Google Patents

Abstract

The invention discloses a composite forming process and a method for preparing near alpha high temperature titanium alloy foil, which belong to the technical field of titanium alloy material processing, and mainly comprise cooling multidirectional forging, lining plate rolling and pulse current auxiliary rolling, and comprise the following steps: s1, weighing raw materials, and smelting an ingot; s2, cooling and multidirectional forging; s3, preparing a high-temperature titanium alloy plate blank; s4, rolling the lining plate; s5, pulse current auxiliary rolling. The composite forming process and method for preparing the near alpha high-temperature titanium alloy foil not only effectively solve the problem of poor forming precision of a lining plate, but also effectively solve the problems of poor surface quality, serious edge cracking and the like in the forming of the high-temperature titanium alloy cold rolled foil, and in the rolling process of a high-temperature titanium alloy sheet or foil at room temperature, pulse current is introduced, so that the single deformation of the material at room temperature in a cold rolling way can be enhanced, the tempering times are greatly reduced, the processing steps are shortened, and the processing time is saved.

Description

A composite forming process and method for preparing near-alpha high-temperature titanium alloy foils

Technical field

The present invention relates to the technical field of titanium alloy material processing, and in particular to a composite forming process and method for preparing near-α high-temperature titanium alloy foils.

Background technique

In the aerospace field, titanium alloys are favored because of their low density, high strength, corrosion resistance, high temperature resistance, and many other advantages. Among them, high-temperature titanium alloys have excellent high-temperature strength and structural stability, as well as high oxidation resistance and creep resistance. Variable resistance has irreplaceable advantages, and high-temperature titanium alloy honeycomb structures play a vital role in components such as wing honeycomb panels of hypersonic aircraft due to their lightweight, high-strength, and high-temperature resistance. At present, there are many reports about high-temperature titanium alloy plates at home and abroad, and few involve high-temperature titanium alloy cold-rolled foils. Problems such as serious edge cracks and poor surface quality of high-temperature titanium alloy cold-rolled foils have been difficult to solve and are becoming increasingly unsatisfactory. The rapid development of aerospace, hypersonic vehicles and automobiles.

In addition, a hard lining plate is added during rolling, that is, hard-plate rolling. During lining plate rolling, the blank is sandwiched between two hard lining plates and has no direct contact with the roll, so heat transfer It is mainly transmitted from the lining plate to the roll, which greatly reduces the cooling rate of the sample, reduces the error between the actual rolling temperature and the theoretical rolling temperature, and improves the plasticity of the material. At the same time, the original line contact between the roller and the blank is changed to the surface contact between the liner and the blank. This process converts part of the shear stress into compressive stress, which effectively alleviates the problem of edge cracks. Therefore, liner rolling can greatly enhance the single deformation of the material, shorten the processing steps, and save processing time. However, when the thickness of the high-temperature titanium alloy plate is low, the liner and the roller will undergo slight elastic deformation, making it difficult to control the accuracy of the blank during liner rolling.

Contents of the invention

The purpose of the present invention is to provide a composite forming process and method for preparing near-α high-temperature titanium alloy foils, which not only effectively avoids the problem of poor forming accuracy in liner manufacturing, but also effectively solves the problems existing in the forming of high-temperature titanium alloy cold-rolled foils. Poor surface quality, severe edge cracks and other problems, and during the rolling process of high-temperature titanium alloy sheet rolling or foil rolling at room temperature, the introduction of pulse current can enhance the single deformation of the material at room temperature cold rolling and greatly reduce the number of temperings. Shorten processing steps and save processing time.

In order to achieve the above object, the present invention provides a composite forming process and method for preparing near-α high-temperature titanium alloy foil. The process and method mainly include cooling multi-directional forging, liner rolling and pulse current-assisted rolling, which includes Following steps:

S1. Weigh the raw materials, smelt the raw materials and cast them into ingots to prepare near-α high-temperature titanium alloy ingots;

S2. The obtained near-α high-temperature titanium alloy ingot is subjected to 3 to 5 passes of cooling multi-directional forging to obtain a forged billet;

S3. Cut the blank obtained in step S2 into a 2mm thick slab, vacuum anneal the slab, and cool it in the furnace to obtain a high-temperature titanium alloy slab with fine grains and high plasticity;

S4, lining rolling

Use GH4049 as a hard lining plate with a thickness of 1.5 to 3 mm. Apply lubricant to the surface of the high-temperature titanium alloy slab obtained in step S3 and the lining plate on one side. Under the conditions of 800°C to 950°C, perform 3 to 10 The temperature is reduced by 30 to 50°C in each pass, and vacuum annealing is performed between each pass. After the rolling is completed, straightening is performed, and the high-temperature titanium alloy slab and liner are separated. After surface cleaning, 0.5 ±0.03mm thick titanium alloy slab;

S5, pulse current assisted rolling

The titanium alloy slab obtained in step S4 is sheared and sent to a six-roller reversing rolling mill for 4 to 10 passes of pulse current-assisted rolling at room temperature, with a deformation of 15% to 40% in each pass. As the temperature increases, the deformation gradually increases, and vacuum annealing is performed every 3 to 4 passes. The annealing temperature is 650 to 700°C, the time is 1 to 3 minutes, and the vacuum degree is 10 ^-2 to 10 ^-1 Pa. Finally, a high-temperature titanium alloy foil with a thickness of 0.03mm~0.06mm is obtained.

Preferably, in step S1, one or more of titanium sponge, high-purity aluminum, pure tin particles, zirconium sponge, crystalline silicon, Al-Mo, Al-Nb and Al-W master alloy are used as raw materials. .

Preferably, the above raw materials are weighed according to the element ratio of the titanium alloy ingredients, and smelted using a vacuum induction shell melting furnace or a vacuum consumable electrode arc melting furnace.

Preferably, in the step S2, the surface of the high-temperature titanium alloy ingot obtained in the step S1 is painted with a high-temperature resistant and anti-oxidation coating, and after it is completely dry, it is put into a heating furnace and heated to raise the temperature. ~50°C, 20°C below the β transformation temperature, 60°C below the β transformation temperature, 100°C below the β transformation temperature, and 140°C above the β transformation temperature, and perform 3 to 5 passes of cooling multi-directional forging.

Preferably, the heat preservation is performed at corresponding temperatures for 60 to 90 minutes before forging, and the total deformation in the thickness direction of the high-temperature titanium alloy ingot is greater than 50%.

Preferably, in step S3, the vacuum annealing process specifically includes: placing the slab under the conditions of raising the temperature to 650 to 750°C, holding the temperature for 1 to 3 minutes, and vacuum degree of 10 ^-2 to 10 ^-1 Pa. Put it into a vacuum heating furnace for vacuum annealing, and then cool it with the furnace to obtain a high-temperature titanium alloy slab.

Preferably, in the step S4, when the high-temperature titanium alloy slab is subjected to 3 to 10 passes of cooling rolling, the deformation amount of the slab in each pass is 20 to 50%.

Preferably, vacuum annealing is performed between each pass of cooling rolling. The specific annealing conditions adopt an annealing temperature of 650 to 750°C, a time of 1 to 5 minutes, and a vacuum degree of 10 ^-4 to 10 ^-3 Pa.

Preferably, in step S5, the pulse current adopts a square wave power supply with a frequency of 300-800Hz, a voltage of 10-100V, and a duty cycle of 1-10%.

Preferably, the prepared high-temperature titanium alloy foil has an average grain size of 3 to 6 μm, a tensile strength of 1100 to 1200 MPa, a yield strength of 990 to 1000 MPa, and an elongation of not less than 8%.

Therefore, the present invention adopts the above-mentioned composite forming process and method for preparing near-alpha high-temperature titanium alloy foils, which not only effectively avoids the problem of poor forming accuracy of lining plates, but also effectively solves the problems existing in the forming of high-temperature titanium alloy cold-rolled foils. Poor surface quality, severe edge cracks and other problems, and during the rolling process of high-temperature titanium alloy sheet rolling or foil rolling at room temperature, the introduction of pulse current can enhance the single deformation of the material at room temperature cold rolling and greatly reduce the number of temperings. Shorten processing steps and save processing time.

Description of drawings

Figure 1 is a principle flow chart of a composite forming process and method for preparing near-α high-temperature titanium alloy foils according to the present invention.

Detailed ways

The technical solution of the present invention will be further described below through the accompanying drawings and specific embodiments.

Unless otherwise defined, technical terms or scientific terms used in the present invention shall have the usual meaning understood by a person with ordinary skill in the field to which the present invention belongs.

Figure 1 is a principle flow chart of a composite forming process and method for preparing near-α high-temperature titanium alloy foil materials. The technical solution of the present invention is explained according to specific embodiments.

Embodiment 1

Preparation of near-α high-temperature titanium alloy Ti-1100 foil with a thickness of 0.03mm

The composition of Ti-1100 is Ti-6Al-2.75Sn-4.0Zr-0.4Mo-0.45Si

S1. Use a variety of sponge titanium, high-purity aluminum, pure tin particles, sponge zirconium, crystalline silicon, Al-Mo, Al-Nb and Al-W master alloys as raw materials, and proportion according to the high-temperature titanium alloy components, and All the raw materials are added to the vacuum induction shell melting furnace, and vacuum induction melting is performed three times to obtain near-α high-temperature titanium alloy ingots;

S2. Paint the surface of the ingot obtained in step S1 with high-temperature resistant and anti-oxidation paint, and perform three passes of cooling and multi-directional forging; put the billet into the heating furnace to heat up to 1095°C, keep it warm for 90 minutes, and perform the first multi-directional forging; first Immediately after the second forging, put the billet into the heating furnace, raise the temperature to 1045℃, keep it warm for 60 minutes, and perform the second multi-directional forging; immediately after the second forging, put the billet into the heating furnace, raise the temperature to 995℃, and perform the third multi-directional forging. Forge forward to obtain a blank whose total deformation in the thickness direction is greater than 50%;

S3. Cut the forged billet obtained in step S2 into 2mm thick slabs, and perform vacuum annealing. Put the slab into a vacuum heating furnace, raise the temperature to 700°C, and keep it for 3 minutes. The vacuum degree is 10 ^-2 ~ 10 ^{- 1} Pa, and then cooled in the furnace to obtain a high-temperature titanium alloy slab;

S4. Use GH4049 as the hard lining plate. The thickness of the lining plate is 1.5mm. Apply lubricant on the surface of the slab and the single side of the lining plate. Conduct 4 tests at high temperatures of 950°C, 900°C, 850°C and 800°C respectively. The cooling rolling is performed in several passes. The deformation in the first three passes is 30%, and the deformation in the fourth pass is 25%. Vacuum annealing is performed between each pass during the rolling process. The annealing temperature is 650°C and the time is 1 minute; rolling is completed. Afterwards, straightening is carried out, the slab and lining plate are separated, finishing and surface cleaning are performed, and finally a 0.5mm thick titanium alloy slab is obtained;

S5. Pulse power supply auxiliary rolling: Connect the pulse power supply to the six-roller reversible rolling mill, and adjust the power supply parameters to output a square wave pulse with a frequency of 300Hz, a voltage of 10V, and a duty cycle of 1%. The obtained 0.5mm thick titanium alloy slab is sheared and sent to a six-roller reversing rolling mill. It is cold-rolled 7 times with the assistance of pulse current. The deformation of the first pass and the fifth pass is 20%. The deformation of the remaining passes is 20%. The deformation amount is all 30%. After the fourth pass, a vacuum annealing treatment at 650°C for 1 minute is performed, and the vacuum degree is 10 ^-4 ~ 10 ^-3 Pa. Finally, a rolled high-temperature titanium alloy foil with a thickness of 0.05mm was obtained.

In this embodiment, the near-α high-temperature titanium alloy Ti-1100 foil with a thickness of 0.05mm prepared by the above process and method has an average grain size of 3 to 6 μm, a tensile strength of 1100MPa, a yield strength of 990MPa, and an elongation of 11 %, foil thickness deviation ±0.012mm.

Embodiment 2

Preparation of near-α high-temperature titanium alloy IMI834 foil with a thickness of 0.04mm

The composition of IMI834 is Ti-5.8Al-4Sn-3.5Zr-0.5Mo-0.7Nb-0.35Si

S1. Use a variety of sponge titanium, high-purity aluminum, pure tin particles, sponge zirconium, crystalline silicon, Al-Mo, Al-Nb and Al-W master alloys as raw materials, and proportion according to the high-temperature titanium alloy components, and All the raw materials are added to the vacuum induction shell melting furnace, and vacuum induction melting is performed three times to obtain near-α high-temperature titanium alloy ingots;

S2. Paint the surface of the ingot obtained in step S1 with high-temperature resistant and anti-oxidation paint, and perform three passes of cooling and multi-directional forging; put the billet into the heating furnace to heat up to 1130°C, keep it warm for 90 minutes, and perform the first multi-directional forging; first Immediately after the second forging, put the billet into the heating furnace, raise the temperature to 1080℃, keep it warm for 60 minutes, and perform the second multi-directional forging; immediately after the second forging, put the billet into the heating furnace, raise the temperature to 1030℃, and perform the third multi-directional forging. Forge forward to obtain a blank whose total deformation in the thickness direction is greater than 50%;

S3. Cut the forged billet obtained in step S2 into 2mm thick slabs, and perform vacuum annealing. Put the slab into a vacuum heating furnace, raise the temperature to 700°C, and keep it for 2 minutes. The vacuum degree is 10 ^-2 ~ 10 ^{- 1} Pa, and then cooled in the furnace to obtain a high-temperature titanium alloy slab;

S4. Use GH4049 as the hard lining plate. The thickness of the lining plate is 1.5mm. Apply lubricant on the surface of the slab and the single side of the lining plate. Conduct 4 tests at high temperatures of 950°C, 900°C, 850°C and 800°C respectively. The cooling rolling is performed in several passes. The deformation in the first three passes is 30%, and the deformation in the fourth pass is 25%. Vacuum annealing is performed between each pass during the rolling process. The annealing temperature is 700°C and the time is 2 minutes; rolling is completed. Afterwards, straightening is carried out, the slab and lining plate are separated, finishing and surface cleaning are performed, and finally a 0.5mm thick titanium alloy slab is obtained;

S5. Pulse power supply auxiliary rolling: Connect the pulse power supply to the six-roller reversible rolling mill, and adjust the power supply parameters to output a square wave pulse with a frequency of 500Hz, a voltage of 50V, and a duty cycle of 5%. The obtained 0.5mm thick titanium alloy slab is sheared and sent to a six-roller reversing rolling mill. It is cold-rolled 7 times with the assistance of pulse current. The deformation of the first pass and the fifth pass is 20%. The deformation of the remaining passes is 20%. The deformation amount is all 30%. After the fourth pass, a vacuum annealing treatment at 650°C for 2 minutes is performed, and the vacuum degree is 10 ^-4 ~ 10 ^-3 Pa. It is also necessary to consider whether the foil thickness can reach 0.05mm after 4 passes. If the above work cannot be continued, a rolled high-temperature titanium alloy foil with a thickness of 0.05mm will eventually be obtained.

In this embodiment, the 0.05mm thick near-α high-temperature titanium alloy IMI834 foil prepared by the above process and method has an average grain size of 3 to 6 μm, a tensile strength of 1150MPa, a yield strength of 997MPa, and an elongation of 11%. Foil thickness deviation ±0.013mm.

Embodiment 3

Preparation of nearly α high-temperature titanium alloy Ti-6Al-3Sn-1Mo-1Nb-1W-9Zr-0.45Si foil with a thickness of 0.05mm

S1. Use a variety of sponge titanium, high-purity aluminum, pure tin particles, sponge zirconium, crystalline silicon, Al-Mo, Al-Nb and Al-W master alloys as raw materials, and proportion according to the high-temperature titanium alloy components, and All the raw materials are added to the vacuum induction shell melting furnace, and vacuum induction melting is performed three times to obtain near-α high-temperature titanium alloy ingots;

S2. Paint the surface of the ingot obtained in step S1 with high-temperature resistant and anti-oxidation paint, and perform three passes of cooling and multi-directional forging; put the billet into the heating furnace to heat up to 1100°C, keep it for 90 minutes, and perform the first multi-directional forging; first Immediately after the second forging, put the billet into the heating furnace, raise the temperature to 1050℃, keep it warm for 60 minutes, and perform the second multi-directional forging; immediately after the second forging, put the billet into the heating furnace, raise the temperature to 980℃, and perform the third multi-directional forging. Forge forward to obtain a blank whose total deformation in the thickness direction is greater than 50%;

S3. Cut the forged billet obtained in step S2 into 2mm thick slabs, and perform vacuum annealing. Put the slab into a vacuum heating furnace, raise the temperature to 700°C, and keep it for 3 minutes. The vacuum degree is 10 ^-2 ~ 10 ^{- 1} Pa, and then cooled in the furnace to obtain a high-temperature titanium alloy slab;

S4. Use GH4049 as the hard lining plate. The thickness of the lining plate is 1.5mm. Apply lubricant on the surface of the slab and the single side of the lining plate. Conduct 4 tests at high temperatures of 950°C, 900°C, 850°C and 800°C respectively. During the cooling rolling, the deformation in the first three passes is 30%, and the deformation in the fourth pass is 25%. Vacuum annealing is performed between each pass during the rolling process. The annealing temperature is 700°C and the time is 3 minutes; rolling is completed. Afterwards, straightening is carried out, the slab and the liner are separated, finished, and the surface is cleaned, and finally a 0.5mm thick titanium alloy slab is obtained;

S5. Pulse power supply-assisted rolling: Connect the pulse power supply to the six-roller reversible rolling mill, and adjust the power supply parameters to output a square wave pulse with a frequency of 600Hz, a voltage of 25V, and a duty cycle of 5%. The obtained 0.5mm thick titanium alloy slab is sheared and sent to a six-roller reversing rolling mill. It is cold-rolled 7 times with the assistance of pulse current. The deformation of the first pass and the fifth pass is 20%. The deformation of the remaining passes is 20%. The deformation amount is 30%. After the fourth pass, a vacuum annealing treatment at 900°C for 2 minutes is performed, and the vacuum degree is 10 ^-4 ~ 10 ^-3 Pa. Finally, a rolled high-temperature titanium alloy foil with a thickness of 0.05mm was obtained.

In this embodiment, the 0.05mm thick near-α high-temperature titanium alloy Ti-6Al-3Sn-1Mo-1Nb-1W-9Zr-0.45Si foil prepared by the above process and method has an average grain size of 3 to 6 μm. , tensile strength 1180MPa, yield strength 995MPa, elongation 10%, foil thickness deviation ±0.01mm.

Embodiment 4

Preparation of nearly α high temperature titanium alloy BT36 foil with a thickness of 0.06mm

S1. Use a variety of sponge titanium, high-purity aluminum, pure tin particles, sponge zirconium, crystalline silicon, Al-Mo, Al-Nb and Al-W master alloys as raw materials, and proportion according to the high-temperature titanium alloy components, and All the raw materials are added to the vacuum induction shell melting furnace, and vacuum induction melting is performed three times to obtain near-α high-temperature titanium alloy ingots;

S2. Paint the surface of the ingot obtained in step S1 with high-temperature resistant and anti-oxidation paint, and perform three passes of cooling and multi-directional forging; put the billet into the heating furnace to heat up to 1100°C, keep it for 90 minutes, and perform the first multi-directional forging; first Immediately after the second forging, put the billet into the heating furnace, raise the temperature to 1050℃, keep it warm for 60 minutes, and perform the second multi-directional forging; immediately after the second forging, put the billet into the heating furnace, raise the temperature to 980℃, and perform the third multi-directional forging. Forge forward to obtain a blank whose total deformation in the thickness direction is greater than 50%;

S3. Cut the forged billet obtained in step S2 into 2mm thick slabs, and perform vacuum annealing. Put the slab into a vacuum heating furnace, raise the temperature to 750°C, and keep it for 3 minutes. The vacuum degree is 10 ^-2 ~ 10 ^{- 1} Pa, and then cooled in the furnace to obtain a high-temperature titanium alloy slab;

S4. Use GH4049 as the hard lining plate. The thickness of the lining plate is 3mm. Apply lubricant on the surface of the slab and the single side of the lining plate. Conduct 4 passes under high temperature conditions of 950℃, 900℃, 850℃ and 800℃ respectively. Cooling rolling, the deformation in the first three passes is 30%, and the deformation in the fourth pass is 25%. Vacuum annealing is performed between each pass during the rolling process. The annealing temperature is 750°C and the time is 5 minutes; after the rolling is completed Straightening, separating the slab and lining plate, finishing, surface cleaning, and finally obtaining a 0.5mm thick titanium alloy slab;

S5. Pulse power supply-assisted rolling: Connect the pulse power supply to the six-roller reversible rolling mill, and adjust the power supply parameters to output a square wave pulse with a frequency of 800Hz, a voltage of 100V, and a duty cycle of 10%. The obtained 0.5mm thick titanium alloy slab is sheared and sent to a six-roller reversing rolling mill. It is cold rolled 7 times with the assistance of pulse current. The deformation of the first pass and the fifth pass is 20%, and the remaining passes The deformation amount is all 30%. After the fourth pass, a vacuum annealing treatment is performed at 750°C for 2 minutes, and the vacuum degree is 10 ^-4 ~ 10 ^-3 Pa. Finally, a rolled high-temperature titanium alloy foil with a thickness of 0.05mm was obtained.

In this embodiment, the 0.05mm thick near-α high-temperature titanium alloy BT36 foil prepared by the above process and method has an average grain size of 3 to 6 μm, a tensile strength of 1200MPa, a yield strength of 1000MPa, and an elongation of 12%. Foil thickness deviation ±0.014mm.

Therefore, the present invention adopts the above-mentioned composite forming process and method for preparing near-alpha high-temperature titanium alloy foils, which not only effectively avoids the problem of poor forming accuracy of lining plates, but also effectively solves the problems existing in the forming of high-temperature titanium alloy cold-rolled foils. Poor surface quality, severe edge cracks and other problems, and during the rolling process of high-temperature titanium alloy sheet rolling or foil rolling at room temperature, the introduction of pulse current can enhance the single deformation of the material at room temperature cold rolling and greatly reduce the number of temperings. Shorten processing steps and save processing time.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: The technical solution of the present invention may be modified or equivalently substituted, but these modifications or equivalent substitutions cannot cause the modified technical solution to depart from the spirit and scope of the technical solution of the present invention.

Claims (9)

1. A composite forming process for preparing near-α high-temperature titanium alloy foils, which is characterized in that: the process mainly includes cooling multi-directional forging, liner rolling and pulse current-assisted rolling, which includes the following steps: S1. Weigh the raw materials, smelt the raw materials and cast them into ingots to prepare near-α high-temperature titanium alloy ingots; S2. The obtained near-α high-temperature titanium alloy ingot is subjected to 3 or 5 passes of cooling multi-directional forging to obtain a forged billet; The surface of the high-temperature titanium alloy ingot obtained in step S1 is painted with a high-temperature resistant and anti-oxidation coating. After it is completely dry, it is put into a heating furnace and heated to a temperature of 30-50°C above the β-transition temperature and 20°C below the β-transition temperature. 60°C below the β transformation temperature, 100°C below the β transformation temperature, and 140°C above the β transformation temperature, perform 3 or 5 passes of cooling multi-directional forging, and perform 1 pass of multi-directional forging at each corresponding temperature; S3. Cut the blank obtained in step S2 into a 2mm thick slab, vacuum anneal the slab, and cool it in the furnace to obtain a high-temperature titanium alloy slab with fine grains and high plasticity; S4, lining rolling Use GH4049 as a hard lining plate with a thickness of 1.5 to 3 mm. Apply lubricant to the surface of the high-temperature titanium alloy slab obtained in step S3 and the lining plate on one side. Under the conditions of 800°C to 950°C, perform 3 to 10 The temperature is reduced by 30 to 50°C in each pass, and vacuum annealing is performed between each pass. After the rolling is completed, straightening is performed, and the high-temperature titanium alloy slab and liner are separated. After surface cleaning, 0.5 ±0.03mm thick titanium alloy slab; S5, pulse current assisted rolling The titanium alloy slab obtained in step S4 is sheared and sent to a six-roller reversing rolling mill for 4 to 10 passes of pulse current-assisted rolling at room temperature, with a deformation of 15% to 40% in each pass. As the temperature increases, the deformation gradually increases, and vacuum annealing is performed every 3 to 4 passes. The annealing temperature is 650 to 700°C, the time is 1 to 3 minutes, and the vacuum degree is 10 ^-2 to 10 ^-1 Pa. Finally, a high-temperature titanium alloy foil with a thickness of 0.03mm~0.06mm is obtained. 2. A composite forming process for preparing near-α high-temperature titanium alloy foils according to claim 1, characterized in that: in the step S1, sponge titanium, high-purity aluminum, pure tin particles, sponge zirconium, One or more of crystalline silicon, Al-Mo, Al-Nb and Al-W master alloy are used as raw materials. 3. A composite forming process for preparing near-α high-temperature titanium alloy foils according to claim 2, characterized in that: the above-mentioned raw materials are weighed according to the element proportions of the titanium alloy ingredients, and a vacuum induction shell melting furnace is used. Or vacuum consumable electrode arc melting furnace for smelting. 4. A composite forming process for preparing near-α high-temperature titanium alloy foils according to claim 1, characterized in that: in the step S2, heat preservation is performed at corresponding temperatures for 60 to 90 minutes before forging. The total deformation in the thickness direction of high-temperature titanium alloy ingots is greater than 50%. 5. A composite forming process for preparing near-α high-temperature titanium alloy foil according to claim 1, characterized in that: in the step S3, the vacuum annealing process specifically includes: heating to 650-750°C, heat preservation Under the conditions of a time of 1 to 3 minutes and a vacuum degree of 10 ^-2 to 10 ^-1 Pa, the slab is placed in a vacuum heating furnace for vacuum annealing, and is cooled with the furnace to obtain a high-temperature titanium alloy slab. 6. A composite forming process for preparing near-α high-temperature titanium alloy foils according to claim 1, characterized in that: in the step S4, the high-temperature titanium alloy slab is subjected to 3 to 10 passes of cooling rolling. During the production process, the deformation of the slab in each pass is 20 to 50%. 7. A composite forming process for preparing near-α high-temperature titanium alloy foils according to claim 6, characterized in that: vacuum annealing is performed between each pass of cooling and rolling, and the specific annealing conditions adopt an annealing temperature of 650 to 750°C. ℃, the time is 1 to 5 minutes, and the vacuum degree is 10 ^-4 to 10 ^-3 Pa. 8. A composite forming process for preparing near-alpha high-temperature titanium alloy foils according to claim 1, characterized in that: in the step S5, the pulse current adopts a frequency of 300-800Hz, a voltage of 10-100V, and an Square wave power supply with a void ratio of 1 to 10%. 9. A composite forming process for preparing near-α high-temperature titanium alloy foils according to any one of claims 1 to 8, characterized in that: the average grain size of the prepared high-temperature titanium alloy foils is 3 to 6 μm. The tensile strength is 1100~1200MPa, the yield strength is 990~1000MPa, and the elongation is not less than 8%.