A titanium alloy welding method

Abstract

The present invention belongs to the technical field of material welding and discloses a titanium alloy welding method, comprising: pre-treating the surface of the titanium alloy to be welded; sandblasting and magnetron sputtering the pre-treated surface to be welded, and sputtering an iron film on the surface to be welded; annealing the titanium alloy after the iron film is sputtered on the surface to be welded under an argon atmosphere; and welding the surface to be welded with the sputtered iron film by a diffusion welding process. The present invention utilizes the characteristic that iron can promote the mutual diffusion of titanium alloys, combines surface sandblasting, magnetron sputtering, stress relief annealing and diffusion welding processes, so that the titanium alloy interface is tightly connected and the grains are intact. While maintaining the strength of the titanium alloy, the plasticity does not significantly decrease, and can meet the needs of large-scale and integrated aircraft engines.

Description

Technical Field

[0001] The invention belongs to the technical field of material welding and relates to a welding method for titanium alloy. Background Art

[0002] Across numerous sectors of modern industry, titanium alloys have emerged as a critical material, garnering significant attention due to their exceptional performance. Due to their numerous advantages, including high specific strength, low thermal conductivity, and excellent corrosion resistance, titanium alloys are widely used in aerospace. In the manufacture of aerospace engines, the use of titanium alloys significantly improves the thrust-to-weight ratio and serviceability of these engines. These engines generate greater thrust while remaining relatively lightweight, enhancing key performance characteristics such as flight speed and climb rate. Furthermore, they are capable of long-term, stable operation under extreme operating conditions, including high temperatures, high pressures, and high rotational speeds.

[0003] With the rapid development of aerospace technology, aerospace vehicles are becoming larger, more complex, and more integrated. Diffusion welding, a common metalworking process, offers high joint strength, excellent sealing, a high degree of automation, and the ability to join a variety of materials, meeting the high joint strength requirements of aircraft structures.

[0004] At present, after diffusion welding of titanium alloys, the interface connection of the welded parts is mostly unable to be completely closed, which leads to tiny gaps or defects at the weld interface. The interface grains are also incomplete. The growth and arrangement of the grains are affected by the welding process and cannot reach the grain state of the parent material, making its strength and elongation lower than that of the parent material. The insufficient strength causes the welded parts to fracture prematurely when subjected to stress, while the low elongation causes the welded parts to lack sufficient toughness when subjected to deformation, making them prone to cracking. These problems seriously limit the wider application of titanium alloys in the aerospace field, especially in critical parts that require extremely high structural strength and reliability. Therefore, a process is needed to optimize the weldability of titanium alloys and improve the strength and plasticity of the welded parts. Summary of the Invention

[0005] The object of the present invention is to provide a titanium alloy welding method to solve the problem that the strength and plasticity of the existing titanium alloy welding interface are lower than those of the parent material.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A titanium alloy welding method comprising:

[0008] Pre-treat the surface of titanium alloy to be welded;

[0009] The pre-treated surface to be welded is subjected to sandblasting and magnetron sputtering, and an iron film is sputtered on the surface to be welded;

[0010] Annealing the titanium alloy after sputtering an iron film on the surface to be welded in an argon atmosphere;

[0011] The annealed titanium alloy surfaces to be welded are welded by diffusion welding process.

[0012] Furthermore, the pretreatment method is:

[0013] After grinding the surface of the titanium alloy to be welded with 3000# sandpaper, the titanium alloy is ultrasonically cleaned with acetone or ethanol.

[0014] Furthermore, during the sandblasting process, aluminum oxide is used as sandblasting material.

[0015] Furthermore, during the sandblasting process, the sandblasting distance is 50-200 mm, the sandblasting angle is 90°, the compressed air pressure used for sandblasting is 0.3-0.6 MPa, and the sandblasting time is 1-5 min.

[0016] Furthermore, the target material for the magnetron sputtering treatment is a high-purity iron target with a purity of 99.99%, and the gas for the magnetron sputtering treatment is argon with a purity of 99.99%.

[0017] Furthermore, during the magnetron sputtering process, the sputtering current is 60-80 mA, the sputtering gas pressure is 8-20 Pa, the single sputtering deposition time is 40-60 s, and the number of sputtering depositions is 5-10 times.

[0018] Furthermore, the mass of the iron film sputtered on the surface to be welded is 0.35% to 0.6% of the mass of the titanium alloy.

[0019] Furthermore, the purity of the argon atmosphere in the annealing treatment is 99.99%.

[0020] Furthermore, during the annealing process, the annealing temperature is 300-600° C., and the annealing time is 1-3 hours.

[0021] Furthermore, during the welding process, the temperature of the diffusion welding process is 40-50° C. below the β phase transition temperature, the welding time is 1-3 hours, and the welding pressure is 2-10 MPa.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a titanium alloy welding method, which comprises the following steps: first, after pretreatment, sandblasting the surface of the titanium alloy to be welded to improve film adhesion, then introducing an iron film as an intermediate layer on the surface of the titanium alloy to be welded by a magnetron sputtering process, then performing a stress relief annealing process to eliminate the internal stress of the titanium alloy, promote diffusion between the iron film and the titanium alloy base material, and finally welding the surfaces of the titanium alloy to be welded together by a diffusion welding process. The present invention is simple to operate and has low cost. By combining surface sandblasting, magnetron sputtering, stress relief annealing and diffusion welding processes, the surface sandblasting can roughen the surface of the titanium alloy and improve film adhesion; magnetron sputtering can obtain a suitable intermediate layer and improve interface connection properties; stress relief annealing can eliminate the internal stress between the iron film and the titanium alloy base material, promote uniform structure, and promote diffusion between the iron film and the titanium alloy base material, further improve the adhesion of the iron film and prevent it from falling off; finally, the diffusion layer obtained by the diffusion welding process has complete grains and a structure mainly composed of needle-shaped α phase and β phase alternatingly distributed, so that the titanium alloy interface is tightly connected. The titanium alloy welded in the present invention maintains the strength of the titanium alloy base material while having no significant decrease in plasticity, can meet the needs of large-scale and integrated aviation engines, can be used on a large scale, and has broad application prospects.

[0024] Furthermore, the present invention uses an iron film as the intermediate layer. Iron is a fast-diffusion element in α-Ti, and its diffusion rate is 10 times that of the α-Ti self-diffusion rate. 3 ~10 5 times. When titanium alloy contains iron, it can enhance the self-diffusion ability of titanium alloy and improve the interface bonding ability of titanium alloy. At the same time, as a strong β-phase stabilizing element, the presence of a small amount of iron in α-type titanium alloy can reduce the β / α phase transition temperature, expand the β phase region, improve the plasticity of the titanium alloy's welded parts, and reduce the tendency of weld cracks.

[0025] Furthermore, the present invention uses aluminum oxide to perform sandblasting on the surface to be welded after pretreatment. The rough surface formed after sandblasting provides good mechanical bite conditions between the iron film and the titanium alloy, which can improve the adhesion of the iron film on the surface to be welded of the titanium alloy.

[0026] Furthermore, the present invention performs magnetron sputtering on the surface to be welded after sandblasting, forming a uniform, dense iron film on the titanium alloy surface. The presence of the iron film promotes diffusion and bonding between atoms, improves the interfacial bonding state, enhances the bonding force of the weld joint, and increases the strength of the weld joint. Furthermore, the magnetron sputtering instrument is simple and convenient to use, with a fast target material sputtering deposition rate and low cost, enabling large-scale coating production.

[0027] Furthermore, the present invention performs annealing treatment on the titanium alloy after sputtering the iron film on the surface to be welded, which can eliminate the internal stress between the iron film and the titanium alloy base material, promote diffusion between each other, improve the interface connection properties after coating, and thus reduce the welding temperature and shorten the welding time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 Schematic diagram of titanium alloy welding of the present invention.

[0030] Figure 2 This is a curve diagram of pressure changing with time during the welding process of the present invention.

[0031] Figure 3 This is a line scan image of the interface diffusion layer of Example 1 of the present invention.

[0032] Figure 4 This is a line scan image of the interface diffusion layer of Example 2 of the present invention.

[0033] Figure 5 This is a line scan image of the interface diffusion layer of Example 3 of the present invention.

[0034] Figure 6 This is a line scan image of the interface diffusion layer of Example 4 of the present invention. DETAILED DESCRIPTION

[0035] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0036] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0037] All features, such as values, amounts, contents, and concentrations, described herein as numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0038] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0039] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0040] The following examples utilize conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or as recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art.

[0041] The present invention is described in further detail below with reference to the accompanying drawings:

[0042] The present invention provides a titanium alloy welding method, which specifically comprises the following steps:

[0043] Step 1: Pre-treat the surface of the titanium alloy to be welded, grind it with 3000# sandpaper, and then ultrasonically clean the titanium alloy with acetone or ethanol.

[0044] Step 2: Use a microjet micro sandblasting machine and select aluminum oxide as sandblasting to roughen the pre-treated titanium alloy surface to be welded to improve the film adhesion of the surface to be welded.

[0045] During the sandblasting process, the sandblasting distance is 50~200mm, the sandblasting angle is 90°, the compressed air pressure used for sandblasting is 0.3~0.6MPa, and the sandblasting time is 1~5min.

[0046] Step 3: Using a magnetron sputtering process, a thin iron film is deposited on the titanium alloy surface to be welded. The target material for magnetron sputtering is a high-purity iron target with a purity of 99.99%, and the gas used for magnetron sputtering is argon with a purity of 99.99%. During the magnetron sputtering process, the sputtering current is 60-80 mA, the sputtering pressure is 8-20 Pa, the single sputtering deposition time is 40-60 seconds, and the number of sputtering depositions is 5-10. After sputtering, the mass of the iron film deposited on the surface to be welded is 0.35%-0.6% of the mass of the titanium alloy.

[0047] Step 4: Anneal the titanium alloy after sputtering the iron film on the surface to be welded in an argon atmosphere with a purity of 99.99%. During the annealing process, the annealing temperature is 300~600℃ and the annealing time is 1~3h.

[0048] Step 5: Connect the annealed titanium alloy surfaces to be welded together through diffusion welding process, such as Figure 1 shown.

[0049] During the welding process, the temperature of the diffusion welding process is 40~50℃ below the β phase transformation temperature, the welding time is 1~3h, and the welding pressure is 2~10MPa.

[0050] like Figure 2 As shown, during the heating stage, the pressure increases from 0 to P1 within t1 time. During the insulation stage, the pressure P1 increases to P2 within t2 time. During the cooling stage, the pressure decreases from P2 to P3 within t3 time. After the temperature reaches room temperature, the pressure decreases from P3 to 0. Among them, P1, P2 and P3 are 60%, 100% and 30% of the total pressure P respectively, and the range of t1 is 10min≤t1≤0.1t 升 , t2 range is 3min≤t2≤0.1t 保 , t3 range is 20min≤t3≤50min, where t 升 Indicates the time spent in the heating stage, t 保 Indicates the holding stage time.

[0051] The present invention is further described in detail below through specific embodiments:

[0052] Example 1:

[0053] The material used in this embodiment is 50*50*2mm Ti60 titanium alloy, which is a Ti-5.8A1-4Sn-3.5Zr-0.7Nb-0.5Mo-0.3Si near-α titanium alloy with a β phase transition temperature of 1035±5°C.

[0054] Step 1) Grind the surface of the Ti60 titanium alloy to be welded with 3000# sandpaper, and then clean the Ti60 titanium alloy with acetone ultrasonically;

[0055] Step 2) sandblasting the surface of the Ti60 titanium alloy to be welded, using aluminum oxide as the sandblasting material, the compressed air pressure used for sandblasting is 0.3 MPa, the sandblasting distance is 50 mm, the sandblasting angle is 90°, and the sandblasting time is 1 min;

[0056] Step 3) The Ti60 titanium alloy surface to be welded is subjected to magnetron sputtering treatment, with a sputtering gas pressure of 20 Pa, a sputtering current of 80 mA, a single sputtering deposition time of 60 s, and a number of sputtering depositions of 5 times. After the sputtering is completed, the mass of the iron film on the surface to be welded on one side is 0.35% of the mass of the titanium alloy on this side, and the mass of the iron film on the surface to be welded on the other side is 0.43% of the mass of the titanium alloy on this side;

[0057] Step 4) annealing the Ti60 titanium alloy to be welded in an argon atmosphere tube furnace at a temperature of 300°C, first heating to 290°C at a rate of 10°C / min, then heating to 300°C at a rate of 1°C / min, holding for 2 hours, and then cooling to room temperature in the furnace;

[0058] Step 5) Diffusion welding of Ti60 titanium alloy was performed with a welding temperature of 980°C and a pressure of 4 MPa. The temperature was first raised to 970°C at a rate of 10°C / min, and then raised to 980°C at a rate of 1°C / min, and kept at this temperature for 1 hour. During the heating stage, the pressure increased from 0 to 2.4 MPa in 15 minutes. During the holding stage, the pressure increased from 2.4 MPa to 4 MPa in 4 minutes. During the cooling stage, the pressure decreased from 4 MPa to 1.2 MPa in 30 minutes. After cooling to room temperature in the furnace, the pressure decreased to 0.

[0059] The mechanical properties of the welded Ti60 titanium alloy were tested and compared with the Ti60 titanium alloy base material. The results are shown in Table 1. It can be seen that the strength of the Ti60 titanium alloy after welding in Example 1 of the present invention is higher than that of the Ti60 titanium alloy base material, with a tensile strength of 1170 MPa and a yield strength of 984 MPa. At the same time, the plasticity is slightly lower than that of the Ti60 titanium alloy base material, and the elongation is 7.26%, showing excellent comprehensive mechanical properties. Figure 3 This is a line scan of the interface diffusion layer of the Ti60 titanium alloy after welding in Example 1. Figure 3 It can be seen that the weld interface is complete without defects, the grains around the weld are refined, and the Fe element diffuses to both sides along the weld interface with a diffusion width of 20 μm. The surface Fe promotes the bonding of the weld interface.

[0060] Table 1 Room temperature tensile properties of Ti60 titanium alloy after welding in Example 1

[0061]

[0062] Example 2:

[0063] The materials used in this embodiment are 30*30*10mm Ti60 titanium alloy and Ti65 titanium alloy, wherein the Ti60 titanium alloy is a Ti-5.8A1-4Sn-3.5Zr-0.7Nb-0.5Mo-0.3Si near-α titanium alloy, and the Ti65 titanium alloy is a 10-component near-α titanium alloy of Ti-5.9Al-4.0Sn-3.5Zr-0.3Mo-0.4Si-0.3Nb-2.0Ta-1.0W-0.05C. The β phase transition temperature of the Ti60 titanium alloy is 1035±5°C, and the β phase transition temperature of the Ti65 titanium alloy is 957±5°C.

[0064] Step 1) After grinding the surfaces of the Ti60 titanium alloy and the Ti65 titanium alloy to be welded with 3000# sandpaper, the Ti60 titanium alloy and the Ti65 titanium alloy are ultrasonically cleaned with ethanol;

[0065] Step 2) sandblasting the surfaces of the Ti60 titanium alloy and the Ti65 titanium alloy to be welded, using aluminum oxide as the sandblasting medium, the compressed air pressure used for sandblasting is 0.4 MPa, the sandblasting distance is 100 mm, the sandblasting angle is 90°, and the sandblasting time is 3 minutes;

[0066] Step 3) performing magnetron sputtering treatment on the surfaces to be welded of the Ti60 titanium alloy and the Ti65 titanium alloy, respectively, with a sputtering gas pressure of 15 Pa, a sputtering current of 60 mA, a single sputtering deposition time of 60 s, and a number of sputtering depositions of 10 times. After the sputtering is completed, the mass of the iron film on the surface to be welded of the Ti60 titanium alloy is 0.52% of the mass of the Ti60 titanium alloy, and the mass of the iron film on the surface to be welded of the Ti65 titanium alloy is 0.47% of the mass of the Ti65 titanium alloy;

[0067] Step 4) The Ti60 titanium alloy and Ti65 titanium alloy to be welded are annealed in a tube furnace in an argon atmosphere at a temperature of 400°C. The temperature is first increased to 390°C at a rate of 10°C / min, then increased to 400°C at a rate of 1°C / min, held at that temperature for 3 hours, and then cooled to room temperature in the furnace.

[0068] Step 5) Diffusion welding of Ti60 titanium alloy and Ti65 titanium alloy was performed at a welding temperature of 910°C and a pressure of 10 MPa. The temperature was first raised to 900°C at a rate of 10°C / min, and then raised to 910°C at a rate of 1°C / min, and kept at this temperature for 3 hours. During the heating stage, the pressure was increased from 0 to 6 MPa in 30 minutes. During the holding stage, the pressure was increased from 6 MPa to 10 MPa in 7 minutes. During the cooling stage, the pressure was reduced from 10 MPa to 3 MPa in 40 minutes. After cooling to room temperature in the furnace, the pressure was reduced to 0.

[0069] The mechanical properties of the welded Ti60 titanium alloy and Ti65 titanium alloy were tested and compared with the Ti60 titanium alloy parent material and the Ti65 titanium alloy parent material. The results are shown in Table 2. It can be seen that the strength of the Ti60 titanium alloy and the Ti65 titanium alloy after welding in Example 2 of the present invention is slightly lower than that of the Ti65 titanium alloy parent material, but significantly higher than the Ti60 titanium alloy parent material. The tensile strength is 1250 MPa, reaching 99.7% of the tensile strength of the Ti65 titanium alloy parent material, and the yield strength is 1143 MPa. At the same time, the plasticity is between that of the Ti60 titanium alloy and the Ti65 titanium alloy, and the elongation is 8.49%, showing excellent comprehensive mechanical properties. Figure 4 This is a line scan of the interface diffusion layer of Ti60 titanium alloy and Ti65 titanium alloy after welding in Example 2. Figure 4 It can be seen that the weld interface is complete without defects, the grains around the weld are refined, and the Fe element diffuses to both sides along the weld interface with a diffusion width of 22 μm. The surface Fe promotes the bonding of the weld interface.

[0070] Table 2 Room temperature tensile properties of Ti60 titanium alloy and Ti65 titanium alloy after welding in Example 2

[0071]

[0072] Example 3:

[0073] The material used in this embodiment is 30*30*4mm Ti65 titanium alloy, which is a 10-component near-α titanium alloy of Ti-5.9Al-4.0Sn-3.5Zr-0.3Mo-0.4Si-0.3Nb-2.0Ta-1.0W-0.05C, and the β phase transition temperature is 957±5°C.

[0074] Step 1) Grind the surface of the Ti65 titanium alloy to be welded with 3000# sandpaper, and then clean the Ti65 titanium alloy with ethanol through ultrasonic cleaning;

[0075] Step 2) sandblasting the Ti65 titanium alloy surface to be welded, using aluminum oxide as the sandblasting material, the compressed air pressure used for sandblasting is 0.5 MPa, the sandblasting distance is 140 mm, the sandblasting angle is 90°, and the sandblasting time is 4 minutes;

[0076] Step 3) The Ti65 titanium alloy surface to be welded is subjected to magnetron sputtering treatment, with a sputtering gas pressure of 8 Pa, a sputtering current of 65 mA, a single sputtering deposition time of 55 s, and a number of sputtering depositions of 8 times. After the sputtering is completed, the mass of the iron film on the surface to be welded on one side is 0.55% of the mass of the titanium alloy on this side, and the mass of the iron film on the surface to be welded on the other side is 0.54% of the mass of the titanium alloy on this side;

[0077] Step 4) annealing the Ti65 titanium alloy to be welded in an argon atmosphere tube furnace at a temperature of 500°C, first heating to 490°C at a rate of 10°C / min, then heating to 500°C at a rate of 1°C / min, holding for 1 hour, and then cooling to room temperature in the furnace;

[0078] Step 5) Diffusion welding of Ti65 titanium alloy was performed at a welding temperature of 900°C and a pressure of 2 MPa. The temperature was first raised to 890°C at a rate of 10°C / min, and then raised to 900°C at a rate of 1°C / min, and kept at this temperature for 2 h. During the heating stage, the pressure increased from 0 to 1.2 MPa in 7 min. During the holding stage, the pressure increased from 1.2 MPa to 2 MPa in 3 min. During the cooling stage, the pressure decreased from 2 MPa to 0.6 MPa in 33 min. After cooling to room temperature in the furnace, the pressure decreased to 0.

[0079] The mechanical properties of the welded Ti65 titanium alloy were tested and compared with the Ti65 titanium alloy base material. The results are shown in Table 3. It can be seen that the strength of the Ti65 titanium alloy after welding in Example 3 of the present invention is close to that of the Ti65 titanium alloy base material, with a tensile strength of 1243 MPa, a yield strength of 1145 MPa, and an elongation of 7.52%, showing excellent comprehensive mechanical properties and plasticity. Figure 5 This is a line scan of the interface diffusion layer of the Ti65 titanium alloy after welding in Example 3. Figure 5 It can be seen that the weld interface is complete without defects, the grains around the weld are refined, and the Fe element diffuses to both sides along the weld interface with a diffusion width of 25 μm. The surface Fe promotes the bonding of the weld interface.

[0080] Table 3 Room temperature tensile properties of Ti65 titanium alloy after welding in Example 3

[0081]

[0082] Example 4:

[0083] The material used in this embodiment is 40*40*5mm Ti175 titanium alloy, wherein the Ti175 alloy is an α+β titanium alloy of Ti-6.5Al-2Sn-3.5Zr-4Mo-1W-0.2Si, and the β phase transition temperature is 985±5°C.

[0084] Step 1) Grind the surface of the Ti175 titanium alloy to be welded with 3000# sandpaper, and then clean the Ti175 titanium alloy with acetone ultrasonically;

[0085] Step 2) sandblasting the Ti175 titanium alloy surface to be welded, using aluminum oxide as the sandblasting medium, the compressed air pressure used for sandblasting is 0.6 MPa, the sandblasting distance is 200 mm, the sandblasting angle is 90°, and the sandblasting time is 5 min;

[0086] Step 3) Magnetron sputtering was performed on the surface of the Ti175 titanium alloy to be welded, with a sputtering pressure of 15 Pa, a sputtering current of 60 mA, a single sputtering deposition time of 40 s, and 10 sputtering deposition times. After the sputtering was completed, the mass of the iron film on the surface to be welded on one side was 0.60% of the mass of the titanium alloy on this side, and the mass of the iron film on the surface to be welded on the other side was 0.57% of the mass of the titanium alloy on this side;

[0087] Step 4) annealing the Ti175 titanium alloy to be welded in an argon atmosphere tube furnace at a temperature of 600°C, first heating to 590°C at a rate of 10°C / min, then heating to 600°C at a rate of 1°C / min, holding for 1 hour, and then cooling to room temperature in the furnace;

[0088] Step 5) Diffusion welding of Ti175 titanium alloy was performed with a welding temperature of 940°C and a pressure of 10 MPa. The temperature was first raised to 930°C at a rate of 10°C / min, and then raised to 940°C at a rate of 1°C / min, and kept at this temperature for 2 hours. During the heating stage, the pressure was increased from 0 to 6 MPa in 25 minutes. During the holding stage, the pressure was increased from 6 MPa to 10 MPa in 6 minutes. During the cooling stage, the pressure was reduced from 10 MPa to 3 MPa in 45 minutes. After cooling to room temperature in the furnace, the pressure was reduced to 0.

[0089] The mechanical properties of the welded Ti175 titanium alloy were tested and compared with the Ti175 titanium alloy base material. The results are shown in Table 4. It can be seen that the strength and plasticity of the Ti175 titanium alloy after welding in Example 4 of the present invention are close to those of the Ti175 titanium alloy base material. The tensile strength reaches 1254 MPa, which is 98.8% of the Ti175 titanium alloy base material. The yield strength reaches 1034 MPa and the elongation is 12.26%, showing excellent comprehensive mechanical properties. Figure 6 This is a line scan of the interface diffusion layer of the Ti175 titanium alloy after welding in Example 4. Figure 6 It can be seen that the weld interface is complete without defects, the grains around the weld are refined, and the Fe element diffuses to both sides along the weld interface with a diffusion width of 25 μm. The surface Fe promotes the bonding of the weld interface.

[0090] Table 4 Room temperature tensile properties of Ti175 titanium alloy after welding in Example 4

[0091]

[0092] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A titanium alloy welding method, characterized in that: include: Pre-treat the surface of titanium alloy to be welded; The pre-treated surface to be welded is subjected to sandblasting and magnetron sputtering, and an iron film is sputtered on the surface to be welded; Annealing the titanium alloy after sputtering an iron film on the surface to be welded in an argon atmosphere; The annealed titanium alloy surfaces to be welded are welded by diffusion welding process; The mass of the iron film sputtered on the surface to be welded is 0.35% to 0.6% of the mass of the titanium alloy; In the welding, the temperature of the diffusion welding process is 40-50° C. below the β phase transformation temperature, the welding time is 1-3 hours, and the welding pressure is 2-10 MPa.

2. The titanium alloy welding method according to claim 1, characterized in that: The pretreatment method is: After grinding the surface of the titanium alloy to be welded with 3000# sandpaper, the titanium alloy is ultrasonically cleaned with acetone or ethanol.

3. The titanium alloy welding method according to claim 1, characterized in that: In the sandblasting process, aluminum oxide is used as sandblasting material.

4. The titanium alloy welding method according to claim 1, characterized in that: In the sandblasting treatment, the sandblasting distance is 50-200 mm, the sandblasting angle is 90°, the compressed air pressure used for sandblasting is 0.3-0.6 MPa, and the sandblasting time is 1-5 min.

5. The titanium alloy welding method according to claim 1, characterized in that: The target material for the magnetron sputtering treatment is a high-purity iron target with a purity of 99.99%, and the gas for the magnetron sputtering treatment is argon with a purity of 99.99%.

6. The titanium alloy welding method according to claim 1, characterized in that: In the magnetron sputtering process, the sputtering current is 60-80 mA, the sputtering gas pressure is 8-20 Pa, the single sputtering deposition time is 40-60 s, and the number of sputtering depositions is 5-10 times.

7. The titanium alloy welding method according to claim 1, characterized in that: The purity of the argon atmosphere in the annealing process is 99.99%.

8. The titanium alloy welding method according to claim 1, characterized in that: In the annealing treatment, the annealing temperature is 300-600° C. and the annealing time is 1-3 hours.

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