A method for cyclic creep deformation that induces selective precipitation of Ti2Al phase

Abstract

The application relates to a cyclic creep deformation method for selectively precipitating Ti2Al phases, and belongs to the technical field of high-niobium TiAl alloys. The application aims to solve the technical problem that it is difficult to obtain the reinforcing phase Ti2Al phase precipitated at the B2 / gamma phase interface. The method comprises the following steps: S1, raw material preparation; S2, smelting; S3, homogenizing annealing treatment; and S4, cyclic creep. The application provides a cyclic creep deformation method in the form of trapezoidal wave loading, reasonable peak and valley stress sizes and load holding time are used to effectively induce the Ti2Al phase to selectively precipitate at the B2 / gamma phase interface, and the precipitated Ti2Al phase can effectively pin dislocations and relieve local stress concentration at the B2 / gamma phase interface. The cyclic creep deformation method also activates the dislocation slip system in the B2 phase, improves the deformation capacity of the brittle B2 phase, and promotes the coordinated deformation between the B2 phase and the gamma phase. The application is used for obtaining high-performance TiAl alloys.

Description

Technical Field

[0001] This invention relates to the field of high-niobium TiAl alloy technology, specifically to a cyclic creep deformation method for inducing selective precipitation of the Ti2Al phase. Background Technology

[0002] Since its development, high-niobium TiAl alloys have been favored by researchers due to their advantages such as low density, high specific strength, high specific stiffness, and excellent oxidation resistance, and they meet the increasingly stringent requirements of the aerospace industry for lightweight, high-temperature resistant engine blade materials. Therefore, high-niobium TiAl alloys are considered a promising next-generation aero-engine blade material that can replace some nickel-based superalloys.

[0003] To meet service requirements, developing TiAl alloys with excellent strength and toughness coordination is of significant engineering importance. Extensive literature review reveals that TiAl alloys with different microstructures exhibit varying properties. Among the four typical microstructures—near-γ, bimodal, near-lamellar, and fully lamellar—TiAl alloys with near-lamellar structures maintain a certain degree of ductility while maintaining high strength. Near-lamellar structures are mainly composed of α2 / γ lamellar clusters and blocky B2 and γ phases at the lamellar cluster interfaces (grain boundaries), with the B2 phase being intrinsically brittle. Under external forces during service, the alloy deforms. Due to the numerous and easily activated slip systems within the γ phase, deformation is primarily driven by the γ phase. Conversely, the slip systems of dislocations within the B2 phase are difficult to activate. Consequently, the deformation of the blocky B2 and γ phases at the lamellar cluster interfaces is not coordinated, easily leading to the initiation of voids and cracks, ultimately resulting in alloy fracture failure. Therefore, effectively avoiding or delaying the formation and propagation of cracks at the B2 / γ phase interface is one of the main approaches to improving the properties of near-lamellar TiAl alloys.

[0004] Currently, the main process for improving the properties of TiAl alloys is the addition of alloying elements. Insoluble alloying elements precipitate as a second phase, acting as a second-phase strengthening agent, effectively pinning dislocations and hindering crack propagation. However, the specific distribution of the reinforcing phase within the microstructure is difficult to control, making it challenging to accurately obtain the reinforcing phase precipitated at the B2 / γ phase interface. Therefore, the addition of most alloying elements is insufficient to prevent crack nucleation and propagation at the B2 / γ phase interface. The discovery of the Ti2Al phase provides a possibility for the appearance of precipitates at the B2 / γ phase interface. The Ti2Al phase is an unstable intermediate phase in the α2→γ phase transformation, primarily induced under high temperature or stress. As a brittle phase, it can hinder dislocation movement. If it precipitates at the B2 / γ phase interface, it can effectively alleviate stress concentration at the phase interface and hinder crack propagation. However, current research has only observed the precipitation of the Ti2Al phase in elongated strips at the α2 / γ lamellar interface or within the lamellars in microstructures after creep and heat exposure, while the precipitation of the Ti2Al phase at the B2 / γ phase interface has been rarely reported. Therefore, developing a reasonable process to induce the precipitation of the Ti2Al phase at the bulk B2 / γ phase interface has significant engineering implications for improving alloy properties. Summary of the Invention

[0005] In order to solve the technical problem that it is difficult to obtain the reinforcing Ti2Al phase precipitated at the B2 / γ phase interface, the present invention provides a cyclic creep deformation method for inducing selective precipitation of Ti2Al phase.

[0006] This invention provides a cyclic creep deformation process under specific waveform loads, which effectively induces the selective precipitation of the Ti2Al phase at the B2 / γ phase interface by maintaining peak and valley stresses for a certain period of time. First, a high-niobium TiAl alloy with a near-lamellar structure is prepared; then, cyclic creep deformation experiments are conducted on the alloy to effectively induce the selective precipitation of the Ti2Al phase at the B2 / γ phase interface.

[0007] A cyclic creep deformation method for inducing selective precipitation of Ti2Al phase is specifically carried out according to the following steps:

[0008] I. Raw material preparation: Weigh the raw materials according to the element mass percentages of Al 41% to 49%, Nb 6% to 9%, Mo ≤ 2%, Cr ≤ 2%, C 0.1% to 0.8%, and the balance Ti. The raw materials include pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy, pure Cr granules, and C powder.

[0009] II. Smelting

[0010] Alcohol cleaning: First, place the pure titanium rod, pure Al block, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules in an ultrasonic cleaner to clean and remove surface impurities;

[0011] Preheating treatment: Place the cleaned pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules into an oven for preheating;

[0012] Feeding: The preheated pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules are sequentially placed into the copper crucible in the water-cooled copper crucible vacuum induction solidification furnace. The C powder is wrapped in Al foil and placed into the secondary feeding hopper.

[0013] Vacuum treatment: When the vacuum level inside the furnace reaches below 5 Pa, argon gas is introduced until the pressure inside the furnace reaches 800 Pa. This process is repeated several times to remove air.

[0014] Heating and melting: The initial heating power is 30-55kW. After the pure titanium rod melts, the power is increased to 60-95kW. After the raw material is completely melted, electromagnetic stirring is performed. Then the power is reduced and a second feeding is performed, adding C powder wrapped in Al foil. The power is increased to 60-95kW and maintained for 15-25 minutes, while electromagnetic stirring is performed for 5-10 minutes to obtain the alloy melt.

[0015] The alloy melt is poured into a mold, cooled to room temperature, and then removed to obtain a high-niobium TiAl alloy ingot.

[0016] 3. Homogenization annealing treatment: The high-niobium TiAl alloy ingot is held at 935-975℃ for 25-40h, and then cooled to room temperature in the furnace to obtain the as-cast high-niobium TiAl alloy.

[0017] IV. Cyclic Creep: ① Prepare a creep specimen from the as-cast high-niobium TiAl alloy and hang the upper and lower clamping ends of the creep specimen on an electronic creep testing machine; ② Apply a preload to fix the creep specimen; ③ Fix three thermocouples to the upper clamping end, lower clamping end, and near the middle of the creep specimen, respectively, and monitor the temperature in real time; ④ Close the heating furnace and start heating to reach the creep temperature of 750-850℃, and hold for 25-55 min; ⑤ Load at a rate of 95-300 N / s to the peak stress of 250-400 MPa, and hold at the peak stress for 5-20 min; then unload at a rate of 95-300 N / s to the valley stress of 50-120 MPa, and hold at the valley stress for 5-20 min; ⑥ Repeat step ⑤ multiple times until the creep specimen fractures; ⑦ Cool to room temperature with the furnace to complete the process.

[0018] Furthermore, the purity of the pure titanium rods in step one is >99.9 wt.%, the purity of the pure Al blocks is >99.9 wt.%, the Mo content in the Al-Mo master alloy is 50.5 wt.%, the Nb content in the Al-Nb master alloy is 52.4 wt.%, and the purity of the pure Cr particles is >99.9 wt.%.

[0019] Furthermore, in step two, the preheating temperature is controlled at 150–350℃, and the preheating time is 25–55 min.

[0020] Furthermore, after the raw materials in step two are completely melted, control the electromagnetic stirring speed to 500-1000 rpm and stir for 5-10 minutes.

[0021] Furthermore, before the second feeding step, the power is reduced to 20-50kW.

[0022] Furthermore, in step three, the temperature is maintained at 940–970℃ for 30–40 hours.

[0023] Furthermore, the creep specimen described in step four has a gauge length of 10 mm, a width of 5 mm, and a thickness of 2 mm.

[0024] Furthermore, in step four, a preload of 200–350 N is applied.

[0025] Furthermore, step four employs the RDL-100 electronic creep testing machine.

[0026] Furthermore, in step four, the temperature is increased at a rate of 25–50 °C / min until the creep temperature is reached.

[0027] Beneficial effects of this invention:

[0028] (1) This invention successfully prepared a high-niobium TiAl alloy with a near-lamellar structure using a vacuum induction melting process. Based on the secondary feeding of C powder and a relatively long electromagnetic stirring time, a TiAl alloy ingot with high microstructure uniformity was obtained.

[0029] (2) This invention proposes a cyclic creep deformation method using trapezoidal wave loading. By utilizing reasonable peak and valley stress magnitudes and holding time, it effectively induces the selective precipitation of Ti2Al phase at the B2 / γ phase interface. Furthermore, the precipitated Ti2Al phase can effectively pin dislocations, alleviating local stress concentration at the B2 / γ phase interface. In addition, this cyclic creep deformation method also activates the dislocation slip system within the B2 phase, improving the deformation capacity of the brittle B2 phase and promoting coordinated deformation between the B2 and γ phases.

[0030] (3) The cyclic creep deformation process proposed in this invention for inducing selective precipitation of Ti2Al phase at the B2 / γ phase interface is simple to operate and low in cost. It can provide new ideas for the research field of controlling the precipitation of reinforcing phase at specific locations and promote the research and development of high-performance TiAl alloys.

[0031] This invention is used to obtain high-performance TiAl alloys. Attached Figure Description

[0032] Figure 1 The images show the microstructure of the as-cast high-niobium TiAl alloy prepared in Example 1, where Figure (a) shows the near-lamellar microstructure and Figure (b) shows the blocky B2 and γ phase morphology at the lamellar interface.

[0033] Figure 2 Figure 1 shows the cyclic creep deformation curves of the as-cast high-niobium TiAl alloy in Example 1. Figure (a) is the stress waveform curve of cyclic creep, Figure (b) is the creep deformation curve, and Figure (c) is a magnified view of the cyclic creep deformation curve in Figure (b).

[0034] Figure 3 Figure 1 shows the microstructure of the as-cast high-niobium TiAl alloy after cyclic creep deformation in Example 1. Figure (a) shows the microstructure of the Ti2Al phase precipitated at the B2 / γ phase interface, and Figure (b) shows the diffraction pattern of the Ti2Al phase. Detailed Implementation

[0035] Specific Implementation Method 1: This implementation method provides a cyclic creep deformation method for inducing selective precipitation of the Ti2Al phase, which is carried out according to the following steps:

[0036] I. Raw material preparation: Weigh the raw materials according to the element mass percentages of Al 41% to 49%, Nb 6% to 9%, Mo ≤ 2%, Cr ≤ 2%, C 0.1% to 0.8%, and the balance Ti. The raw materials include pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy, pure Cr granules, and C powder.

[0037] II. Smelting

[0038] Alcohol cleaning: First, place the pure titanium rod, pure Al block, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules in an ultrasonic cleaner to clean and remove surface impurities;

[0039] Preheating treatment: Place the cleaned pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules into an oven for preheating;

[0040] Feeding: The preheated pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules are sequentially placed into the copper crucible in the water-cooled copper crucible vacuum induction solidification furnace. The C powder is wrapped in Al foil and placed into the secondary feeding hopper.

[0041] Vacuum treatment: When the vacuum level inside the furnace reaches below 5 Pa, argon gas is introduced until the pressure inside the furnace reaches 800 Pa. This process is repeated several times to remove air.

[0042] Heating and melting: The initial heating power is 30-55kW. After the pure titanium rod melts, the power is increased to 60-95kW. After the raw material is completely melted, electromagnetic stirring is performed. Then the power is reduced and a second feeding is performed, adding C powder wrapped in Al foil. The power is increased to 60-95kW and maintained for 15-25 minutes, while electromagnetic stirring is performed for 5-10 minutes to obtain the alloy melt.

[0043] The alloy melt is poured into a mold, cooled to room temperature, and then removed to obtain a high-niobium TiAl alloy ingot.

[0044] 3. Homogenization annealing treatment: The high-niobium TiAl alloy ingot is held at 935-975℃ for 25-40h, and then cooled to room temperature in the furnace to obtain the as-cast high-niobium TiAl alloy.

[0045] IV. Cyclic Creep: ① Prepare a creep specimen from the as-cast high-niobium TiAl alloy and hang the upper and lower clamping ends of the creep specimen on an electronic creep testing machine; ② Apply a preload to fix the creep specimen; ③ Fix three thermocouples to the upper clamping end, lower clamping end, and near the middle of the creep specimen, respectively, and monitor the temperature in real time; ④ Close the heating furnace and start heating to reach the creep temperature of 750-850℃, and hold for 25-55 min; ⑤ Load at a rate of 95-300 N / s to the peak stress of 250-400 MPa, and hold at the peak stress for 5-20 min; then unload at a rate of 95-300 N / s to the valley stress of 50-120 MPa, and hold at the valley stress for 5-20 min; ⑥ Repeat step ⑤ multiple times until the creep specimen fractures; ⑦ Cool to room temperature with the furnace to complete the process.

[0046] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the purity of the pure titanium rod in step one is >99.9 wt.%, the purity of the pure Al block is >99.9 wt.%, the Mo content in the Al-Mo master alloy is 50.5 wt.%, the Nb content in the Al-Nb master alloy is 52.4 wt.%, and the purity of the pure Cr particles is >99.9 wt.%. Everything else is the same as in Specific Implementation Method One.

[0047] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: in step two, the preheating temperature is controlled at 150–350°C, and the preheating time is 25–55 minutes. Everything else is the same as in Specific Implementation Method One or Two.

[0048] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: after the raw materials are completely melted in step two, the electromagnetic stirring speed is controlled at 500-1000 rpm, and stirring is performed for 5-10 minutes. Everything else is the same as in Specific Implementation Methods One to Three.

[0049] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: before the second feeding step, the power is reduced to 20-50kW. Everything else is the same as in Specific Implementation Methods One to Four.

[0050] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that step three involves maintaining the temperature at 940–970°C for 30–40 hours. Everything else is the same as in Specific Implementation Methods One to Five.

[0051] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the gauge length of the creep specimen in step four is 10 mm, the width is 5 mm, and the thickness is 2 mm. Everything else is the same as in Specific Implementation Methods One to Six.

[0052] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that step four involves applying a preload of 200-350N. Everything else is the same as in Specific Implementation Methods One to Seven.

[0053] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that step four uses an RDL-100 electronic creep testing machine. Everything else is the same as in Specific Implementation Methods One to Eight.

[0054] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that: in step four, the temperature is increased at a rate of 25–50 °C / min to reach the creep temperature. Everything else is the same as in Specific Implementation Methods One to Nine.

[0055] The scope of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

[0056] Example 1:

[0057] This embodiment describes a cyclic creep deformation method for inducing selective precipitation of the Ti2Al phase, which is carried out according to the following steps:

[0058] I. Raw Material Preparation: Weigh the raw materials according to the nominal composition of the high-niobium TiAl alloy as Ti-43Al-6Nb-1Mo-1Cr-0.5C (at.%). The raw materials include pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy, pure Cr particles, and C powder. The purity of the pure titanium rods is >99.9 wt.%, the purity of the pure Al blocks is >99.9 wt.%, the Mo content in the Al-Mo master alloy is 50.5 wt.%, the Nb content in the Al-Nb master alloy is 52.4 wt.%, and the purity of the pure Cr particles is >99.9 wt.%.

[0059] II. Smelting

[0060] Alcohol cleaning: First, place the pure titanium rod, pure Al block, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules in an ultrasonic cleaner to clean and remove surface impurities;

[0061] Preheating treatment: Place the cleaned pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules into an oven for preheating. The preheating temperature is 200℃ and the preheating time is 40min.

[0062] Feeding: The preheated pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules are sequentially placed into the copper crucible in the water-cooled copper crucible vacuum induction solidification furnace. The C powder is wrapped in Al foil and placed into the secondary feeding hopper.

[0063] Vacuum treatment: When the vacuum level inside the furnace reaches below 5 Pa, argon gas is introduced until the pressure inside the furnace reaches 800 Pa. This process is repeated three times to remove air.

[0064] Heating and melting: The initial heating power is 35kW. After the pure titanium rod melts, the power is increased to 80kW. After the raw material is completely melted, electromagnetic stirring is performed, and the stirring speed is controlled at 800rpm for 8 minutes. Then the power is reduced to 35kW, and a second feeding is performed, adding C powder wrapped in Al foil. The power is increased to 80kW and maintained for 20 minutes, while electromagnetic stirring is performed for 8 minutes to obtain the alloy melt.

[0065] The alloy melt is poured into a mold, cooled to room temperature, and then removed to obtain a high-niobium TiAl alloy ingot.

[0066] 3. Homogenization annealing treatment: The high-niobium TiAl alloy ingot is held at 950℃ for 36 hours, and then cooled to room temperature in the furnace to obtain the as-cast high-niobium TiAl alloy.

[0067] IV. Cyclic Creep Testing: ① Prepare creep specimens from cast high-niobium TiAl alloy. The gauge length of the creep specimen is 10 mm, the width is 5 mm, and the thickness is 2 mm. Hang the upper and lower clamping ends of the creep specimen on the RDL-100 electronic creep testing machine. ② Apply a preload of 300 N to fix the creep specimen. ③ Fix three thermocouples to the upper clamping end, lower clamping end, and near the middle of the creep specimen, respectively, and monitor the temperature in real time. ④ Close the heating furnace and start heating at a rate of 40℃ / min until the creep temperature of 800℃ is reached, and hold at that temperature for 30 min. ⑤ Load the specimen at a rate of 200 N / s to the peak stress of 300 MPa and hold at the peak stress for 10 min. Then unload the specimen at a rate of 200 N / s to the valley stress of 100 MPa and hold at the valley stress for 10 min. ⑥ Repeat step ⑤ multiple times until the creep specimen fractures. ⑦ Cool the specimen to room temperature with the furnace to complete the test.

[0068] Figure 1 The images show the microstructure of the as-cast high-niobium TiAl alloy prepared in Example 1. Figure (a) shows the near-lamellar microstructure, and Figure (b) shows the morphology of the blocky B2 and γ phases at the lamellar interface. Characterization results from the figures reveal that the alloy microstructure consists of α2 / γ lamellar clusters and blocky B2 and γ phases at the lamellar interface, representing a typical near-lamellar structure. Furthermore, based on… Figure 1 Image (b) shows that no obvious precipitated phases are formed at the blocky B2 / γ phase interface.

[0069] Figure 2 Figure 1 shows the cyclic creep deformation curves of the as-cast high-niobium TiAl alloy in Example 1. Figure (a) shows the stress waveform curve of cyclic creep, Figure (b) shows the creep deformation curve, and Figure (c) is a magnified view of the cyclic creep deformation curve in Figure (b). Figure (a) shows that the as-cast high-niobium TiAl alloy underwent cyclic deformation between a peak stress of 300 MPa and a valley stress of 100 MPa until the sample fractured. Figure (b) shows that within one cycle, the strain of the alloy increases and decreases with the application of peak and valley stresses.

[0070] Figure 3 Figure 1 shows the microstructure of the as-cast high-niobium TiAl alloy after cyclic creep deformation in Example 1. Figure (a) shows the microstructure of the Ti2Al phase precipitated at the B2 / γ phase interface, and Figure (b) shows the diffraction pattern of the Ti2Al phase. It can be seen from the figures that after cyclic creep deformation, the Ti2Al phase precipitated at the blocky B2 / γ phase interface, and there is significant dislocation pile-up nearby, indicating that it effectively hinders dislocation movement. Furthermore, some dislocations can be observed within the blocky B2 phase.

[0071] Based on the above test results, it is confirmed that the cyclic creep deformation process with a specific load waveform implemented in this invention effectively induces the selective precipitation of Ti2Al phase at the B2 / γ phase interface.

Claims

1. A cyclic creep deformation method for inducing selective precipitation of Ti2Al phase, characterized in that This method is specifically carried out in the following steps: I. Raw material preparation: Weigh the raw materials according to the element mass percentages of Al 41% to 49%, Nb 6% to 9%, Mo ≤ 2%, Cr ≤ 2%, C 0.1% to 0.8%, and the balance Ti. The raw materials include pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy, pure Cr granules, and C powder. II. Smelting Alcohol cleaning: First, place the pure titanium rod, pure Al block, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules in an ultrasonic cleaner to clean and remove surface impurities; Preheating treatment: Place the cleaned pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules into an oven for preheating; Feeding: The preheated pure titanium rods, pure Al blocks, Al-Mo master alloy, Al-Nb master alloy and pure Cr granules are sequentially placed into the copper crucible in the water-cooled copper crucible vacuum induction solidification furnace. The C powder is wrapped in Al foil and placed into the secondary feeding hopper. Vacuum treatment: When the vacuum level inside the furnace reaches below 5 Pa, argon gas is introduced until the pressure inside the furnace reaches 800 Pa. This process is repeated several times to remove air. Heating and melting: The initial heating power is 30-55kW. After the pure titanium rod melts, the power is increased to 60-95kW. After the raw material is completely melted, electromagnetic stirring is performed. Then the power is reduced and a second feeding is performed, adding C powder wrapped in Al foil. The power is increased to 60-95kW and maintained for 15-25 minutes, while electromagnetic stirring is performed for 5-10 minutes to obtain the alloy melt. The alloy melt is poured into a mold, cooled to room temperature, and then removed to obtain a high-niobium TiAl alloy ingot.

3. Homogenization annealing treatment: The high-niobium TiAl alloy ingot is held at 935-975℃ for 25-40h, and then cooled to room temperature in the furnace to obtain the as-cast high-niobium TiAl alloy. IV. Cyclic Creep: ① Prepare a creep specimen from the as-cast high-niobium TiAl alloy and hang the upper and lower clamping ends of the creep specimen on an electronic creep testing machine; ② Apply a preload to fix the creep specimen; ③ Fix three thermocouples to the upper clamping end, lower clamping end, and near the middle of the creep specimen, respectively, and monitor the temperature in real time; ④ Close the heating furnace and start heating to reach the creep temperature of 750-850℃, and hold for 25-55 min; ⑤ Load at a rate of 95-300 N / s to the peak stress of 250-400 MPa, and hold at the peak stress for 5-20 min; then unload at a rate of 95-300 N / s to the valley stress of 50-120 MPa, and hold at the valley stress for 5-20 min; ⑥ Repeat step ⑤ multiple times until the creep specimen fractures; ⑦ Cool to room temperature with the furnace to complete the process.

2. The cyclic creep deformation method for inducing selective precipitation of Ti2Al phase according to claim 1, characterized in that... The purity of the pure titanium rods mentioned in Step 1 is >99.9 wt.%, the purity of the pure Al blocks is >99.9 wt.%, the Mo content in the Al-Mo master alloy is 50.5 wt.%, the Nb content in the Al-Nb master alloy is 52.4 wt.%, and the purity of the pure Cr particles is >99.9 wt.%.

3. The cyclic creep deformation method for inducing selective precipitation of Ti2Al phase according to claim 1, characterized in that... Step 2: Control the preheating temperature to 150–350℃ and the preheating time to 25–55 min.

4. The cyclic creep deformation method for inducing selective precipitation of Ti2Al phase according to claim 1, characterized in that... After the raw materials are completely melted in step two, control the electromagnetic stirring speed to 500-1000 rpm and stir for 5-10 minutes.

5. The cyclic creep deformation method for inducing selective precipitation of Ti2Al phase according to claim 1, characterized in that... Before the second feeding step, reduce the power to 20-50kW.

6. The cyclic creep deformation method for inducing selective precipitation of Ti2Al phase according to claim 1, characterized in that... Step 3: Keep warm at 940-970℃ for 30-40 hours.

7. The cyclic creep deformation method for inducing selective precipitation of Ti2Al phase according to claim 1, characterized in that... The creep specimen described in step four has a gauge length of 10 mm, a width of 5 mm, and a thickness of 2 mm.

8. The cyclic creep deformation method for inducing selective precipitation of Ti2Al phase according to claim 1, characterized in that... Step 4: Apply a preload of 200–350 N.

9. The cyclic creep deformation method for inducing selective precipitation of Ti2Al phase according to claim 1, characterized in that... Step four uses the RDL-100 electronic creep testing machine.

10. The cyclic creep deformation method for inducing selective precipitation of Ti2Al phase according to claim 1, characterized in that... Step four involves heating at a rate of 25–50 °C / min until the creep temperature is reached.

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