Method for improving mechanical properties of additive manufacturing Ti2AlNb alloy

Abstract

The application belongs to the field of metal materials, and particularly relates to a method for improving the mechanical properties of additive manufacturing Ti2AlNb alloy, which comprises the following steps: heating the additive manufacturing Ti2AlNb alloy part to 10-20 DEG C above the beta phase transition point at a heating rate of 30+ / -10 DEG C / min, keeping warm for 2-8 h, and cooling to ambient temperature; then, heating the part to 20-50 DEG C below the beta phase transition point at a heating rate of 10+ / -5 DEG C / min, keeping warm for 1-4 h, and cooling to ambient temperature; then, heating the part to 10-20 DEG C below the beta phase transition point at a heating rate of 10+ / -5 DEG C / min, keeping warm for 0.5-2 h, cooling to 10-20 DEG C above the alpha2 phase transition point, repeating the above treatment for 1-3 times, and cooling to ambient temperature; finally, heating the part to 50-150 DEG C below the alpha2 phase transition point at a heating rate of 10+ / -5 DEG C / min, keeping warm for 22-26 h, and cooling to ambient temperature. The method provided by the application can improve the mechanical strength of additive manufacturing Ti2AlNb alloy.

Description

Technical Field

[0001] This invention belongs to the field of metallic materials, and in particular relates to a method for improving the mechanical properties of additively manufactured Ti2AlNb alloys. Background Technology

[0002] Ti2AlNb alloy is an intermetallic compound with a density of 5.3 g / cm³. 3 ~5.4g / cm 3 It has a long-term operating temperature range of 650℃ to 750℃. It possesses good room temperature plasticity, toughness, and high-temperature strength, as well as good processability, comprehensive mechanical properties, and flame retardant properties. It is considered an important lightweight, high-temperature resistant structural material to replace nickel-based superalloys in the aerospace field.

[0003] With the rapid advancement of aerospace technology, components for aircraft, aero engines, and spacecraft are becoming increasingly larger, more complex, and more integrated. Traditional forging and casting methods are gradually becoming insufficient to meet the manufacturing demands of complex aerospace components. Additive manufacturing technology, which manufactures parts through layer-by-layer deposition, is a near-net-shape forming process that eliminates the need for molds. Compared to traditional manufacturing methods, it is more suitable for the high-quality and rapid manufacturing of complex Ti2AlNb alloy components.

[0004] However, the rapid cooling rate in additive manufacturing results in poor overall mechanical properties of the deposited Ti2AlNb alloy, necessitating heat treatment to improve these properties. However, due to compositional segregation at grain boundaries during the solidification of the molten pool in additive manufacturing, conventional solution aging methods for Ti2AlNb alloys lead to the formation of continuous α2 phases at these grain boundaries. During use, cracks easily form in these continuous α2 phases at the grain boundaries, causing premature aging and negatively impacting mechanical properties, ultimately preventing the material from meeting application requirements. Therefore, a heat treatment regime specifically designed for the unique forming process and microstructure of additively manufactured Ti2AlNb alloys is needed to improve its mechanical properties. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for improving the mechanical properties of additively manufactured Ti2AlNb alloys. This method can improve the strength of additively manufactured Ti2AlNb alloys while maintaining good plasticity, thereby promoting the engineering application of additively manufactured Ti2AlNb alloys.

[0006] This invention provides a method for improving the mechanical properties of additively manufactured Ti2AlNb alloys, comprising the following steps:

[0007] Step 1: Place the additively manufactured Ti2AlNb alloy parts into a heating furnace and heat them from ambient temperature to a temperature range of 10 to 20°C above the β phase transformation point at a heating rate of 30±10°C / min. Hold the temperature for 2 to 8 hours, and then cool them to ambient temperature.

[0008] Step 2: Place the parts processed in Step 1 into a heating furnace and heat them in the furnace at a heating rate of 10±5℃ / min to a temperature range of 20 to 50℃ below the β phase transition point. Hold the temperature for 1 to 4 hours, and then cool them to ambient temperature.

[0009] Step 3: Place the parts processed in Step 2 into a heating furnace and heat them in the furnace at a heating rate of 10±5℃ / min to a temperature range of 10 to 20℃ below the β phase transition point. Hold the temperature for 0.5 to 2 hours, and then cool the furnace to a temperature range of 10 to 20℃ above the α2 phase transition point.

[0010] Step 4: Repeat Step 3 1 to 3 times. During the last repetition, after holding the temperature within a range of 10 to 20°C below the β phase transition point, cool to ambient temperature.

[0011] Step 5: Place the parts processed in Step 4 into a heating furnace and heat them in the furnace at a heating rate of 10±5℃ / min to a temperature range of 50 to 150℃ below the α2 phase transformation point. Hold the temperature for 22 to 26 hours, and then cool them to ambient temperature.

[0012] Preferably, the Al content of the Ti2AlNb alloy is 18–30 at%.

[0013] Preferably, the Nb content of the Ti2AlNb alloy is 10–30 at%.

[0014] Preferably, the β-phase transformation point of the Ti2AlNb alloy is obtained by differential scanning calorimetry or metallographic method.

[0015] Preferably, the α2 phase transformation point of the Ti2AlNb alloy is obtained by differential scanning calorimetry or metallographic method.

[0016] Preferably, the heating furnace used in step one is a vacuum heating furnace or an atmosphere-protected furnace, and the cooling method is air cooling.

[0017] Preferably, the heating furnace used in step two is a vacuum heating furnace or an atmosphere-protected furnace, and the cooling method is air cooling.

[0018] Preferably, the heating furnace used in steps three and four is a vacuum heating furnace or an atmosphere protection furnace, and the cooling method in step four is air cooling.

[0019] Preferably, the heating furnace used in step five is a vacuum heating furnace or an atmosphere-protected furnace, and the cooling method is air cooling.

[0020] Preferably, the ambient temperature is 5–40°C.

[0021] Traditional heat treatment for forged / cast Ti2AlNb alloys involves solution aging. After solution aging, additively manufactured Ti2AlNb alloys develop a continuous α2 phase at grain boundaries. During use, cracks easily initiate and propagate at these continuous grain boundary precipitates, leading to a decrease in alloy strength. This invention addresses these issues. Step one completely dissolves the α2 and O phases in the deposited microstructure of the additively manufactured Ti2AlNb alloy, promoting atomic diffusion within the material, eliminating grain boundary segregation during solidification, and inhibiting the formation of continuous α2 phases at grain boundaries during subsequent heat treatment. This process prevents grain growth, maintains the fine grains formed during rapid cooling in additive manufacturing, ensures good mechanical properties, and ultimately results in a fine-grained single-phase β microstructure. Heating rates less than 30±10℃ / min lead to precipitate formation during heating, while rates greater than 30±10℃ / min cause excessive stress and cracking. Therefore, a heating rate of 30±10℃ / min is selected. Temperatures below 10–20°C above the β phase transition point cannot completely dissolve the α2 and O phases formed in the deposited microstructure, failing to eliminate grain boundary segregation during solidification and inhibiting the formation of continuous α2 phases at grain boundaries during subsequent heat treatment. Temperatures above 10–20°C above the β phase transition point lead to grain growth, damaging the material's mechanical properties. Therefore, the holding temperature is selected within the range of 10–20°C above the β phase transition point. Holding times less than 2 hours result in insufficient atomic diffusion, failing to eliminate grain boundary segregation. Holding times greater than 8 hours do not significantly improve the effect of eliminating grain boundary segregation and instead reduce production efficiency. Therefore, the holding time is selected between 2 and 8 hours. After step two, the α2 phase precipitates from the β phase matrix, and the material's microstructure is composed of both the β phase matrix and the α2 phase. While this microstructure improves the material's mechanical properties to some extent, it also leads to the formation of continuous α2 phases at grain boundaries. When the heating rate is less than 10±5℃ / min, the heating process is too long, reducing production efficiency. When the heating rate is greater than 10±5℃ / min, the α2 phase is difficult to fully precipitate, failing to improve mechanical properties. Therefore, the heating rate is selected at 10±5℃ / min. Holding at a temperature range of 20–50℃ below the β phase transformation point is to maintain good comprehensive mechanical properties of the material. Too high a holding temperature results in too little α2 phase content, while too low a holding temperature results in too little β phase matrix content. Holding time less than 1 hour makes it difficult for the α2 phase to fully precipitate, failing to improve mechanical properties. Holding time greater than 4 hours has no significant effect on α2 phase precipitation and instead reduces production efficiency. Therefore, the holding time is selected between 1 and 4 hours. The purpose of steps three and four is to heat the material to the upper part of the β+α2 phase region, hold it there, and then furnace cool it to the lower part of the β+α2 phase region. During this heating and cooling process, the continuous α2 phase at the grain boundaries will spheroidize, but not completely break up.By performing multiple cycles of heating / cooling, the decomposition of the continuous α2 phase at grain boundaries can be further promoted, increasing the degree of discontinuation of the continuous α2 phase and achieving the goal of eliminating the continuous α2 phase at grain boundaries. Compared with continuous heat preservation, multiple cycles of heating / cooling can intermittently increase the solute element concentration difference, resulting in a better discontinuous effect on the continuous α2 phase at grain boundaries. The optimal effect of destroying the continuous α2 phase at grain boundaries can be achieved within the temperature range of 10–20℃ below the β phase transformation point to 10–20℃ above the α2 phase transformation point. If the heat preservation temperature is too high, the α2 phase content will be too low; if the heat preservation temperature is too low, the β phase matrix content will be too low. If the heat preservation time is less than 0.5 h, the α2 phase is difficult to fully disintegrate, and the effect of improving mechanical properties is not achieved. If the heat preservation time is greater than 2 h, it has no significant effect on the disintegration of the α2 phase and instead reduces production efficiency. Therefore, the heat preservation time is selected between 0.5 and 2 h. When the heating rate is less than 10 ± 5℃ / min, the heating process is too long, reducing production efficiency. When the heating rate exceeds 10±5℃ / min, the α2 phase is difficult to fully break down. Therefore, the heating rate is chosen to be 10±5℃ / min. Repeating step three 1-3 times is necessary because too few cycles will not achieve the desired discontinuous α2 phase at grain boundaries. As the number of cycles increases, the aspect ratio of the α2 phase decreases, the concentration difference between the top and sides of the α2 phase becomes smaller, and diffusion becomes increasingly difficult. Therefore, further increasing the number of cycles will not significantly change the discontinuity of the continuous α2 phase at grain boundaries; instead, it will prolong production time and reduce efficiency. Therefore, the number of repetitions in step three is set to 1-3 times. The purpose of step five is to promote the precipitation of the O phase and secondary α2 phase, further improving the mechanical properties of the material. If the holding temperature is too high, the O phase content will be too low. If the holding temperature is too high, the β phase content will be too low, both of which are detrimental to the mechanical properties of the material. Therefore, the holding temperature is chosen to be within the range of 50-150℃ below the α2 phase transition point. If the holding time is less than 22 hours, the O phase and secondary α2 phase are difficult to fully precipitate, resulting in low content and failing to improve mechanical properties. If the holding time is greater than 26 hours, it has no significant effect on the formation of precipitated phases and actually reduces production efficiency. Therefore, the holding time should be selected between 22 and 26 hours. If the heating rate is less than 10±5℃ / min, the heating process is too long, reducing production efficiency. If the heating rate is greater than 10±5℃ / min, the O phase and secondary α2 phase are difficult to fully precipitate. Therefore, the heating rate should be selected at 10±5℃ / min.

[0022] Experimental results show that the additive manufacturing Ti2AlNb alloy treated by the method of the present invention eliminates continuous precipitates at grain boundaries and improves the mechanical properties of the material. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 A flow chart of the heat treatment process for additive manufacturing of Ti2AlNb alloy provided in an embodiment of the present invention;

[0025] Figure 2 Micrograph of the processed additively manufactured Ti2AlNb alloy part provided in Comparative Example 1 of the present invention;

[0026] Figure 3 The image shows the microstructure of the processed additively manufactured Ti2AlNb alloy part provided in Embodiment 1 of the present invention. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a method for improving the mechanical properties of additively manufactured Ti2AlNb alloys, referring to... Figure 1 This includes the following steps:

[0029] Step 1: Place the additively manufactured Ti2AlNb alloy parts into a heating furnace and heat them from ambient temperature to a temperature range of 10 to 20°C above the β phase transformation point at a heating rate of 30±10°C / min. Hold the temperature for 2 to 8 hours, and then cool them to ambient temperature.

[0030] Step 2: Place the parts processed in Step 1 into a heating furnace and heat them in the furnace at a heating rate of 10±5℃ / min to a temperature range of 20 to 50℃ below the β phase transition point. Hold the temperature for 1 to 4 hours, and then cool them to ambient temperature.

[0031] Step 3: Place the parts processed in Step 2 into a heating furnace and heat them in the furnace at a heating rate of 10±5℃ / min to a temperature range of 10 to 20℃ below the β phase transition point. Hold the temperature for 0.5 to 2 hours, and then cool the furnace to a temperature range of 10 to 20℃ above the α2 phase transition point.

[0032] Step 4: Repeat Step 3 1 to 3 times. During the last repetition, after holding the temperature within a range of 10 to 20°C below the β phase transition point, cool to ambient temperature.

[0033] Step 5: Place the parts processed in Step 4 into a heating furnace and heat them in the furnace at a heating rate of 10±5℃ / min to a temperature range of 50 to 150℃ below the α2 phase transformation point. Hold the temperature for 22 to 26 hours, and then cool them to ambient temperature.

[0034] In the method provided by this invention, the Al content of the Ti2AlNb alloy is preferably 18-30 at%, specifically 18 at%, 19 at%, 20 at%, 21 at%, 22 at%, 23 at%, 24 at%, 25 at%, 26 at%, 27 at%, 28 at%, 29 at%, or 30 at%; the Nb content of the Ti2AlNb alloy is preferably 10-30 at%, specifically 10 at%, 11 at%, 12 at%, 13 at%, 14 at%, 15 at%, 16 at%, 17 at%, 18 at%, 19 at%, 20 at%, 21 at%, 22 at%, 23 at%, 24 at%, 25 at%, 26 at%, 27 at%, 28 at%, 29 at%, or 30 at%.

[0035] In the method provided by the present invention, the β phase transformation point and α2 phase transformation point of the Ti2AlNb alloy are preferably obtained by differential scanning calorimetry or metallographic method.

[0036] In the method provided by the present invention, the ambient temperature is preferably 5 to 40°C, specifically 5°C, 10°C, 15°C, 20°C, 25°C (room temperature), 30°C, 35°C or 40°C.

[0037] In the method provided by the present invention, in step one, the heating furnace used is preferably a vacuum heating furnace or an atmosphere protection furnace.

[0038] In the method provided by this invention, in step one, the heating rate can specifically be 20℃ / min, 21℃ / min, 22℃ / min, 23℃ / min, 24℃ / min, 25℃ / min, 26℃ / min, 27℃ / min, 28℃ / min, 29℃ / min, 30℃ / min, 31℃ / min, 32℃ / min, 33℃ / min, 34℃ / min, 35℃ / min, 36℃ / min, 37℃ / min, 38℃ / min, 39℃ / min, or 40℃ / min.

[0039] In the method provided by the present invention, in step one, the furnace can be heated to 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C or 20°C above the β phase transition point.

[0040] In the method provided by this invention, the heat preservation time in step one can be 2h, 3h, 4h, 5h, 6h, 7h or 8h.

[0041] In the method provided by the present invention, in step one, the cooling method is preferably air cooling.

[0042] In the method provided by the present invention, in step two, the heating furnace used is preferably a vacuum heating furnace or an atmosphere protection furnace.

[0043] In the method provided by the present invention, in step two, the heating rate can specifically be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min or 15℃ / min.

[0044] In the method provided by this invention, in step two, the furnace can be heated to 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C, or 50°C below the β phase transition point.

[0045] In the method provided by this invention, the heat preservation time in step two can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h.

[0046] In the method provided by the present invention, in step two, the cooling method is preferably air cooling.

[0047] In the method provided by the present invention, in step three, the heating furnace used is preferably a vacuum heating furnace or an atmosphere protection furnace.

[0048] In the method provided by the present invention, in step three, the heating rate can specifically be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min or 15℃ / min.

[0049] In the method provided by the present invention, in step three, the furnace can be heated to 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C or 20°C below the β phase transition point.

[0050] In the method provided by this invention, the heat preservation time in step three can be 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2h.

[0051] In the method provided by this invention, in step three, the furnace can be cooled to 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C or 20°C above the α2 phase transition point.

[0052] In the method provided by the present invention, in step four, the number of times step three is repeated can be 1 time, 2 times, or 3 times.

[0053] In the method provided by the present invention, in step four, the heating furnace used is preferably a vacuum heating furnace or an atmosphere protection furnace.

[0054] In the method provided by the present invention, in step four, the preferred cooling method is air cooling.

[0055] In the method provided by the present invention, in step five, the heating furnace used is preferably a vacuum heating furnace or an atmosphere protection furnace.

[0056] In the method provided by the present invention, in step five, the heating rate can specifically be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min or 15℃ / min.

[0057] In the method provided by this invention, in step five, the furnace can be heated to 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, or 150°C below the α2 phase transition point.

[0058] In the method provided by this invention, the heat preservation time in step five can be 22h, 22.5h, 23h, 23.5h, 24h, 24.5h, 25h, 25.5h or 26h.

[0059] In the method provided by the present invention, in step five, the preferred cooling method is air cooling.

[0060] For clarity, the following examples and comparative models will be used to provide a detailed description.

[0061] Comparative Example 1

[0062] This comparative example illustrates the processing steps for additive manufacturing of Ti2AlNb alloy with a chemical composition of Ti-22Al-10Nb (at%) using a solution aging heat treatment method:

[0063] Step 1: Place the additively manufactured Ti2AlNb alloy part into a heating furnace and heat it from room temperature to 980°C at a heating rate of 30°C / min. Hold the temperature for 1 hour and then air cool it to room temperature.

[0064] Step 2: The parts processed in Step 1 are placed in a heating furnace and heated to 790°C at a heating rate of 30°C / min. The temperature is held for 24 hours and then air-cooled to room temperature.

[0065] Microstructural observation of the additively manufactured Ti2AlNb alloy parts after the comparative treatment was performed, and the results are as follows: Figure 2 As shown. (Through) Figure 2 It can be seen that a continuous α2 phase exists at the grain boundaries.

[0066] Example 1

[0067] This embodiment provides a method for improving the mechanical properties of an additively manufactured Ti2AlNb alloy with a chemical composition of Ti-22Al-10Nb (at%). The alloy has a β-phase transformation point of 1100℃ and an α2-phase transformation point of 980℃. The method includes the following steps:

[0068] Step 1: Place the additively manufactured Ti2AlNb alloy part into a heating furnace and heat it from room temperature to 1120℃ at a heating rate of 30℃ / min. Hold it at that temperature for 5 hours and then air cool it to room temperature.

[0069] Step 2: The parts processed in Step 1 are placed in a heating furnace and heated to 1060°C at a heating rate of 10°C / min, held at that temperature for 3 hours, and then air-cooled to room temperature.

[0070] Step 3: Place the parts processed in Step 2 into a heating furnace, heat them to 1080°C at a heating rate of 10°C / min, hold them at that temperature for 1 hour, then cool them to 1000°C in the furnace. Repeat this process, heating them to 1080°C at a heating rate of 10°C / min, holding them at that temperature for 1 hour, then cooling them to 1000°C in the furnace. Repeat this process, heating them to 1080°C at a heating rate of 10°C / min, holding them at that temperature for 1 hour, then air cooling them to room temperature.

[0071] Step 4: Place the parts processed in Step 3 into a heating furnace and heat them to 920°C at a heating rate of 10°C / min. Hold the temperature for 24 hours and then air cool to room temperature.

[0072] The microstructure of the additively manufactured Ti2AlNb alloy parts processed in this embodiment was observed, and the results are as follows: Figure 3 As shown. (Through) Figure 3 It can be seen that there is a discontinuous α2 phase at the grain boundaries.

[0073] Example 2

[0074] This embodiment provides a method for improving the mechanical properties of an additively manufactured Ti2AlNb alloy with a chemical composition of Ti-22Al-25Nb (at%). The alloy has a β-phase transformation point of 1080℃ and an α2-phase transformation point of 1010℃. The method includes the following steps:

[0075] Step 1: Place the additively manufactured Ti2AlNb alloy part into a heating furnace and heat it from room temperature to 1090℃ at a heating rate of 40℃ / min, hold it at that temperature for 8 hours, and then air cool it to room temperature.

[0076] Step 2: The parts processed in Step 1 are placed in a heating furnace and heated to 1040°C at a heating rate of 5°C / min, held at that temperature for 1 hour, and then air-cooled to room temperature.

[0077] Step 3: Place the parts processed in Step 2 into a heating furnace and heat them to 1060°C at a heating rate of 5°C / min. Hold the temperature for 2 hours and then cool them to 1030°C. Repeat this process, heating the parts to 1060°C at a heating rate of 5°C / min and holding the temperature for 2 hours. Then cool them to 1030°C. Repeat this process, heating the parts to 1060°C at a heating rate of 5°C / min and holding the temperature for 2 hours. Then air cool them to room temperature.

[0078] Step 4: Place the parts processed in Step 3 into a heating furnace and heat them to 910°C at a heating rate of 5°C / min. Hold the temperature for 22 hours and then air cool to room temperature.

[0079] The tensile strength of the additively manufactured Ti2AlNb alloys treated in Comparative Example 1 and Examples 1-2 was tested. The results showed that the room temperature tensile strength of the additively manufactured Ti2AlNb alloys treated in Examples 1 and 2 reached 1134 MPa and 1126 MPa, respectively, while the room temperature tensile strength of the additively manufactured Ti2AlNb alloy in Comparative Example 1 using the traditional solution aging heat treatment method was only 962 MPa. The treatment effect of the examples was significantly improved compared with the comparative examples.

[0080] Special note: The technical solution of this invention involves different alloy compositions and many process parameters. The synergistic effect between alloy compositions and process parameters needs to be comprehensively considered in order to obtain the beneficial effects and significant progress of this invention.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for improving the mechanical properties of an additive manufactured Ti2AlNb alloy, characterized in that, The method comprises the following steps: Step one: placing the additive manufacturing Ti2AlNb alloy part into a heating furnace, heating the part in the furnace from ambient temperature to a temperature range 10-20℃ above the β phase transition point at a heating rate of 30±10℃ / min, holding for 2-8h, and then cooling to ambient temperature; Step two: placing the part treated in step one into a heating furnace, heating the part in the furnace to a temperature range 20-50℃ below the β phase transition point at a heating rate of 10±5℃ / min, holding for 1-4h, and then cooling to ambient temperature; Step three: placing the part treated in step two into a heating furnace, heating the part in the furnace to a temperature range 10-20℃ below the β phase transition point at a heating rate of 10±5℃ / min, holding for 0.5-2h, and then cooling the furnace to a temperature range 10-20℃ above the α2 phase transition point; Step four: repeating step three for 1-3 times, and in the last repetition, after holding at a temperature range 10-20℃ below the β phase transition point, cooling to ambient temperature; Step five: placing the part treated in step four into a heating furnace, heating the part in the furnace to a temperature range 50-150℃ below the α2 phase transition point at a heating rate of 10±5℃ / min, holding for 22-26h, and then cooling to ambient temperature.

2. The method of claim 1, wherein, The Ti2AlNb alloy has an Al content of 18-30at%.

3. The method of claim 1, wherein, The Ti2AlNb alloy has an Nb content of 10-30at%.

4. The method of claim 1, wherein, The β phase transition point of the Ti2AlNb alloy is obtained by differential scanning calorimetry or metallography.

5. The method of claim 1, wherein, The α2 phase transition point of the Ti2AlNb alloy is obtained by differential scanning calorimetry or metallography.

6. The method of claim 1, wherein, The heating furnace used in step one is a vacuum heating furnace or an atmosphere protection furnace, and the cooling mode is air cooling.

7. The method of claim 1, wherein, The heating furnace used in step two is a vacuum heating furnace or an atmosphere protection furnace, and the cooling mode is air cooling.

8. The method of claim 1, wherein, The heating furnace used in steps three and four is a vacuum heating furnace or an atmosphere protection furnace, and the cooling mode in step four is air cooling.

9. The method of claim 1, wherein, The heating furnace used in step five is a vacuum heating furnace or an atmosphere protection furnace, and the cooling mode is air cooling.

10. The method according to any one of claims 1 to 9, characterized in that, The ambient temperature is 5-40℃.

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