Nano ceramic particle reinforced titanium-aluminum alloy with excellent high-temperature performance and preparation method

Abstract

The invention provides a nano ceramic particle reinforced titanium-aluminum alloy with excellent high-temperature performance and a preparation method. The preparation method comprises the following steps: mixing Ti powder, Nb powder and B powder to obtain first mixed powder; mixing the first mixed powder with Ti48Al48Cr2Nb2 pre-alloyed powder according to different proportions to obtain a second mixed powder, a third mixed powder and a fourth mixed powder; the second mixed powder, the third mixed powder and the fourth mixed powder are sequentially placed on a titanium thin strip according to a certain proportion and packaged, and a continuous mixed powder titanium cylinder is obtained; a continuous mixed powder titanium cylinder is added into a titanium-aluminum alloy through vacuum induction melting treatment to prepare the nano ceramic particle reinforced titanium-aluminum alloy with excellent high-temperature performance, the reinforced titanium-aluminum alloy has excellent strength and plasticity at high temperature, and the yield strength, the tensile strength and the fracture strain of the reinforced titanium-aluminum alloy at 800 DEG C or above are larger than or equal to 550.6 MPa, larger than or equal to 599.4 MPa and larger than or equal to 22.8% respectively.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance high-temperature alloys, and in particular to a nano-ceramic particle reinforced titanium-aluminum alloy with excellent high-temperature performance and a preparation method thereof. Background Art

[0002] Titanium aluminum alloys are widely used in structural materials such as aerospace engine blades and automotive turbocharger rotors. However, with the continuous improvement of the working temperature requirements of the new generation of power systems, the existing titanium aluminum alloys have problems such as significant attenuation of the strength and other properties of the alloy when used at high temperatures. The existing technology mainly uses alloying modification, heat treatment regulation, and thermal processing process optimization to solve related problems: In terms of alloying modification, the alloy performance attenuation is suppressed by adding precious metal elements such as Mo and Ta, but it causes the segregation of alloy components and the formation of complex phases. While improving the strength of the alloy, it will lead to a decrease in the ductility of the alloy. There are two problems in heat treatment regulation: First, the process window is narrow, and a slight deviation in the process parameters will lead to grain coarsening or uneven organization, which will cause the performance of the material to decrease instead of increase; second, for large-sized or complex geometric components, it is difficult to find relevant heating equipment to achieve uniform regulation of the overall material. The technical problem of hot working technology is that it requires high accuracy of parameters such as forging temperature and strain rate, and is more likely to produce defects such as uneven alloy rheology, residual stress, cold caps and hard and brittle layers. As a result, while the alloy has significantly improved strength, its plasticity or toughness will be reduced and it is not suitable for industrial production. Therefore, how to simplify the process flow and reduce the amount of high-cost elements added to achieve the industrial production of titanium-aluminum alloys that maintain high strength, plasticity and toughness at room temperature or high temperature is a technical problem that urgently needs to be broken through. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a nano-ceramic particle reinforced titanium aluminum alloy with excellent high temperature performance, and its preparation method comprises the following steps:

[0004] Step 1: ball milling Ti powder, Nb powder and B powder at a molar ratio of 1:1:4-4.5 to obtain a first mixed powder, wherein the ball milling time is 6-9 hours, the rotation speed is 40-70 rpm, the particle size range of Ti powder is 10-40 μm, the particle size range of Nb powder is 20-70 μm, and the particle size of B powder is 0.1-1.5 μm;

[0005] Step 2: Mix the first mixed powder prepared in step 1 with Ti with a particle size of 50-140 μm. 48 Al 48 Cr 2 Nb 2The pre-alloyed powders are subjected to ball milling and mixing treatments according to mass ratios of 9-15:1, 4-8:1 and 2-6:1 to obtain the second, third and fourth mixed powders, respectively. The ball milling and mixing treatments are carried out for 6-10 hours at a ball milling speed of 40-80 rpm.

[0006] Step 3: Arrange the second, third and fourth mixed powders obtained in step 2 in sequence on a titanium thin strip in a mass ratio of 1-2:1-2:6-8 and package them to obtain a continuous mixed powder titanium column;

[0007] Step 4: After the TiAl alloy is subjected to vacuum induction melting treatment, the continuous mixed powder titanium cylinder obtained in step 3 is added, the mass ratio of the continuous mixed powder titanium cylinder to the TiAl alloy is 0.5% to 0.8%:1, after the continuous mixed powder titanium cylinder is melted, it is kept warm for 4-10 minutes to generate nano ceramic particles and evenly distribute them, and then cast to obtain nano ceramic particle reinforced titanium aluminum alloy with excellent high temperature performance, the vacuum induction melting treatment is: under argon protection, start heating with a power of 3-10kW, increase by 5-8kW every 3-7 minutes until the alloy is completely melted, and then keep warm for 3-7 minutes, according to mass percentage, the TiAl alloy components include: Al: 33.0-34.5wt.%; Cr: 2.3-2.6wt.%; Nb: 4.7-5.1wt.%; the rest is Ti;

[0008] The microstructure of the nano-ceramic particle reinforced titanium-aluminum alloy with excellent high-temperature performance is a lamellar structure with an average size of ≤122μm. The internal structure contains uniformly distributed nano-ceramic particles with a particle size of 30-400 nanometers. At ≥800°C, the yield strength, tensile strength and fracture strain of the nano-ceramic particle reinforced titanium-aluminum alloy with excellent high-temperature performance are ≥550.6MPa, ≥599.4MPa and ≥22.8% respectively.

[0009] Furthermore, in step 1, the particle size of the Ti powder is in the range of 15-30 μm, the particle size of the Nb powder is in the range of 25-50 μm, and the particle size of the B powder is in the range of 0.2-1.0 μm.

[0010] Furthermore, the ball milling mixing treatment time in step 2 is 7-9 hours, and the ball milling speed is 50-70 rpm.

[0011] Furthermore, the vacuum induction melting treatment described in step 4 is: under argon protection, start heating at a power of 5-8 kW, increase by 5.5-7 kW every 4-6 minutes until the alloy is completely melted, and then keep warm for 4-6 minutes. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1This is a microstructure morphology diagram of the nano-ceramic particle reinforced titanium aluminum alloy 1 with excellent high temperature performance in Example 1 of the present invention;

[0013] Figure 2 The engineering tensile stress-strain curve of the nano-ceramic particle reinforced titanium aluminum alloy 1 with excellent high temperature performance at 800° C. in Example 1 of the present invention;

[0014] Figure 3 This is a microstructure morphology of the nano-ceramic particle reinforced titanium aluminum alloy 2 with excellent high temperature performance in Example 2 of the present invention;

[0015] Figure 4 The engineering tensile stress-strain curve of the nano-ceramic particle reinforced titanium aluminum alloy 2 with excellent high temperature performance at 810° C. in Example 2 of the present invention;

[0016] Figure 5 This is a microstructure morphology of the nano-ceramic particle reinforced titanium aluminum alloy 3 with excellent high temperature performance in Example 3 of the present invention;

[0017] Figure 6 The engineering tensile stress-strain curve of the nano-ceramic particle reinforced titanium aluminum alloy 3 with excellent high temperature performance at 820° C. in Example 3 of the present invention;

[0018] Figure 7 This is a microstructure morphology diagram of the titanium aluminum alloy in Comparative Example 1 of the present invention;

[0019] Figure 8 It is an engineering tensile stress-strain curve diagram of the titanium aluminum alloy at 800°C in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention will be described in detail below. Obviously, these embodiments are only partial but not complete examples of the present invention. Without departing from the concept of the present invention, other implementation methods derived from these embodiments by those skilled in the art should be regarded as the protection scope of the present invention.

[0021] Example 1

[0022] Nano-ceramic particle reinforced titanium aluminum alloy 1 with excellent high temperature performance, its preparation method comprises the following steps:

[0023] Step 1: ball milling Ti powder, Nb powder and B powder at a molar ratio of 1:1:4 to obtain a first mixed powder, wherein the ball milling time is 9 hours, the rotation speed is 60 rpm, the particle size of the Ti powder is 10 μm, the particle size of the Nb powder is 40 μm, and the particle size of the B powder is 0.1 μm;

[0024] Step 2: Mix the first mixed powder prepared in step 1 with Ti with a particle size of 50 μm.48 Al 48 Cr 2 Nb 2 The pre-alloyed powders were subjected to ball milling and mixing treatments according to mass ratios of 9:1, 4:1 and 2:1 to obtain the second, third and fourth mixed powders, respectively. The ball milling and mixing treatments were carried out for 8 hours at a ball milling speed of 50 rpm.

[0025] Step 3: Arrange the second, third and fourth mixed powders obtained in step 2 in sequence on a titanium thin strip in a mass ratio of 1:1:8 and package them to obtain a continuous mixed powder titanium column;

[0026] Step 4: After the TiAl alloy is subjected to vacuum induction melting treatment, the continuous mixed powder titanium cylinder obtained in step 3 is added, the mass ratio of the continuous mixed powder titanium cylinder to the TiAl alloy is 0.8%:1, and after the continuous mixed powder titanium cylinder is melted, it is kept warm for 4 minutes and poured to obtain a nano-ceramic particle reinforced titanium aluminum alloy 1 with excellent high temperature performance. The vacuum induction melting treatment is: under argon protection, heating is started at 5kW power, and 5kW is increased every 4 minutes until the alloy is completely melted, and then kept warm for 6 minutes. In terms of mass percentage, the TiAl alloy components include: Al: 33.0wt.%, Cr: 2.6wt.%, Nb: 4.8wt.%, and the balance is Ti;

[0027] The microstructure of the nano-ceramic particle reinforced titanium aluminum alloy 1 with excellent high temperature performance prepared in this embodiment is as follows: Figure 1 As shown: the microstructure is lamellar, the average size of the lamellar clusters is ~122μm, and the internal structure contains uniformly distributed nano-ceramic particles; Figure 2 It shows that at 800°C, the yield strength, tensile strength and fracture strain of the nano-ceramic particle reinforced titanium aluminum alloy 1 with excellent high temperature performance are 550.6MPa, 599.4MPa and 25.5% respectively.

[0028] Example 2

[0029] Nano-ceramic particle reinforced titanium aluminum alloy 2 with excellent high temperature performance, its preparation method comprises the following steps:

[0030] Step 1: ball milling Ti powder, Nb powder and B powder at a molar ratio of 1:1:4.1 to obtain a first mixed powder, wherein the ball milling time is 8 hours, the rotation speed is 40 rpm, the particle size of the Ti powder is 30 μm, the particle size of the Nb powder is 20 μm, and the particle size of the B powder is 0.5 μm;

[0031] Step 2: Mix the first mixed powder prepared in step 1 with Ti 48 Al 48 Cr 2Nb 2 The pre-alloyed powders were subjected to ball milling and mixing treatments according to mass ratios of 9.5:1, 4.5:1 and 2.5:1 to obtain the second, third and fourth mixed powders, respectively. The ball milling and mixing treatments were carried out for 9 hours at a ball milling speed of 70 rpm.

[0032] Step 3: Arrange the second, third and fourth mixed powders obtained in step 2 in sequence on a titanium thin strip in a mass ratio of 2:2:6 and package them to obtain a continuous mixed powder titanium column;

[0033] Step 4: After the TiAl alloy is subjected to vacuum induction melting treatment, the continuous mixed powder titanium cylinder obtained in step 3 is added, the mass ratio of the continuous mixed powder titanium cylinder to the TiAl alloy is 0.5%:1, and after the continuous mixed powder titanium cylinder is melted, it is kept warm for 7 minutes, and after casting, a nano-ceramic particle reinforced titanium aluminum alloy 2 with excellent high temperature performance is obtained. The vacuum induction melting treatment is: under argon protection, heating is started at 8kW power, and 8kW is increased every 8 minutes until the alloy is completely melted, and then kept warm for 5 minutes. In terms of mass percentage, the TiAl alloy components include: Al: 34.5wt.%, Cr: 2.4wt.%, Nb: 5.1wt.%, and the balance is Ti;

[0034] The microstructure of the nano-ceramic particle reinforced titanium aluminum alloy 2 with excellent high temperature performance prepared in this embodiment is as follows: Figure 3 As shown: the microstructure is lamellar, the average size of the lamellar clusters is ~98μm, and the internal structure contains uniformly distributed nano-ceramic particles; Figure 4 It shows that at 810°C, the yield strength, tensile strength and fracture strain of the nano-ceramic particle reinforced titanium aluminum alloy 2 with excellent high temperature performance are 567.2MPa, 623.7MPa and 24.0% respectively.

[0035] Example 3

[0036] The preparation method of the nano-ceramic particle reinforced titanium aluminum alloy 3 with excellent high temperature performance comprises the following steps:

[0037] Step 1: ball milling Ti powder, Nb powder and B powder at a molar ratio of 1:1:4.2 to obtain a first mixed powder, wherein the ball milling time is 6 hours, the rotation speed is 70 rpm, the particle size of the Ti powder is 40 μm, the particle size of the Nb powder is 70 μm, and the particle size of the B powder is 0.3 μm;

[0038] Step 2: Mix the first mixed powder prepared in step 1 with Ti with a particle size of 140 μm. 48 Al 48 Cr 2 Nb 2The pre-alloyed powders were subjected to ball milling and mixing treatments at mass ratios of 10:1, 5:1 and 3:1 to obtain the second, third and fourth mixed powders, respectively. The ball milling and mixing treatments were carried out for 6 hours at a ball milling speed of 40 rpm.

[0039] Step 3: Arrange the second, third and fourth mixed powders obtained in step 2 in sequence on a titanium thin strip at a mass ratio of 1.5:1.5:7 and package them to obtain a continuous mixed powder titanium column;

[0040] Step 4: After the TiAl alloy is subjected to vacuum induction melting treatment, the continuous mixed powder titanium cylinder obtained in step 3 is added, the mass ratio of the continuous mixed powder titanium cylinder to the TiAl alloy is 0.7%:1, and after the continuous mixed powder titanium cylinder is melted, it is kept warm for 10 minutes, and after casting, a nano-ceramic particle reinforced titanium aluminum alloy 3 with excellent high temperature performance is obtained. The vacuum induction melting treatment is: under argon protection, heating is started at 6kW power, and 6kW is increased every 3 minutes until the alloy is completely melted, and then kept warm for 3 minutes. In terms of mass percentage, the TiAl alloy components include: Al: 34.0wt.%, Cr: 2.3wt.%, Nb: 4.7wt.%, and the balance is Ti;

[0041] The microstructure of the nano-ceramic particle reinforced titanium aluminum alloy 3 with excellent high temperature performance prepared in this embodiment is as follows: Figure 5 As shown: the microstructure is lamellar, the average size of the lamellar clusters is ~105μm, and the internal structure contains uniformly distributed nano-ceramic particles; Figure 6 It shows that at 820°C, the yield strength, tensile strength and fracture strain of the nano-ceramic particle reinforced titanium aluminum alloy 3 with excellent high temperature performance are 558.9 MPa, 615.0 MPa and 22.8% respectively.

[0042] Comparative Example 1

[0043] Titanium aluminum alloy, the preparation method thereof comprises the following steps:

[0044] Step 1: Perform vacuum induction melting treatment on the TiAl alloy and then cast it to obtain a titanium aluminum alloy. The vacuum induction melting treatment is: start heating at 5kW power under argon protection, increase 5kW every 5 minutes until the alloy is completely melted, and then keep warm for 7 minutes. In terms of mass percentage, the TiAl alloy components include: Al: 34.1wt.%, Cr: 2.6wt.%, Nb: 4.9wt.%, and the balance is Ti;

[0045] The microstructure of the titanium aluminum alloy prepared in this comparative example is as follows Figure 7 As shown: the microstructure is lamellar, and the average size of the lamellar clusters is ~153μm; Figure 8It shows that at 800°C, the yield strength, tensile strength and fracture strain of the titanium aluminum alloy are 479.8MPa, 557.5MPa and 20.8% respectively.

[0046] Compared with Comparative Example 1, Examples 1-3 of the present invention are different in that:

[0047] Compared with the size of the titanium aluminum alloy lamellar clusters obtained in Comparative Example 1, the size of the lamellar clusters of the nano-ceramic particle-reinforced titanium aluminum alloy with excellent high-temperature performance obtained in the present invention is significantly refined; and at ≥800°C, the high-temperature mechanical properties of the alloy obtained in the present invention are significantly better than those of the titanium aluminum alloy in Comparative Example 1:

[0048] Among all the embodiments, the size of the tissue lamellae of the nano-ceramic particle reinforced titanium-aluminum alloy 1 with excellent high temperature performance prepared in Example 1 is the largest, wherein the average size of the tissue lamellae is ~122μm, which is 20.3% finer than the titanium-aluminum alloy of Comparative Example 1 (average size of the microstructure lamellae: ~153μm). The yield strength, ultimate tensile strength and fracture strain of the nano-ceramic particle reinforced titanium-aluminum alloy 1 with excellent high temperature performance obtained in Example 1 at 800°C are 550.6MPa, 599.4MPa and 25.5%, respectively, which are increased by 70.8MPa, 41.9MPa and 4.7% respectively compared with the titanium-aluminum alloy of Comparative Example 1, and the improvement ratios are 14.8%, 7.5% and 22.6%, respectively. Therefore, compared with Comparative Example 1, the size of the tissue lamellae of the nano-ceramic particle reinforced titanium-aluminum alloy 1 with excellent high temperature performance obtained in the present invention is smaller, and the mechanical properties such as high temperature strength and plasticity are significantly better than those of the titanium-aluminum alloy obtained in Comparative Example 1.

[0049] The average size of the microstructure lamellae of the nano-ceramic particle reinforced titanium-aluminum alloy 2 with excellent high temperature performance prepared in Example 2 is ~98μm, which is 35.9% finer than the titanium-aluminum alloy obtained in Comparative Example 1 (average size of the microstructure lamellae: ~153μm). The yield strength, ultimate tensile strength and fracture strain of the nano-ceramic particle reinforced titanium-aluminum alloy 2 with excellent high temperature performance at 810°C are 567.2MPa, 623.7MPa and 24.0%, respectively. Under the temperature conditions higher than the application of the comparative example, compared with the titanium-aluminum alloy of Comparative Example 1, they increase by 87.4MPa, 66.2MPa and 3.2%, respectively, and the improvement ratios are 18.2%, 11.9% and 15.4%, respectively. Therefore, under the temperature conditions higher than the application of Comparative Example 1, the nano-ceramic particle reinforced titanium-aluminum alloy 2 with excellent high temperature performance obtained in this embodiment has a smaller size of the tissue lamellae, and the high temperature mechanical properties are significantly better than the titanium-aluminum alloy obtained in Comparative Example 1.

[0050] The average size of the microstructure lamellae of the nano-ceramic particle reinforced titanium-aluminum alloy 3 with excellent high temperature performance prepared in Example 3 is ~105μm, which is 31.4% finer than the titanium-aluminum alloy of Comparative Example 1 (average size of the microstructure lamellae: ~153μm). The yield strength, ultimate tensile strength and fracture strain of the nano-ceramic particle reinforced titanium-aluminum alloy 3 with excellent high temperature performance at 820℃ are 558.9MPa, 615.0MPa and 22.8%, respectively. Under the temperature conditions higher than the comparative example application, compared with the titanium-aluminum alloy of Comparative Example 1, they increase by 79.1MPa, 57.5MPa and 2.0%, respectively, and the improvement ratios are 16.5%, 10.3% and 9.6%, respectively. Therefore, in this embodiment, under the condition of using a temperature higher than that of Comparative Example 1, the size of the tissue lamellae of the nano-ceramic particle reinforced titanium-aluminum alloy 3 with excellent high temperature performance is smaller, and the high temperature mechanical properties are significantly better than those of the titanium-aluminum alloy obtained in Comparative Example 1.

[0051] Comparative Example 2

[0052] Wenchen Xu et al. published an article titled Improvement of microstructure, mechanical properties and hot workability of a TiAl-Nb-Mo alloy through hot extrusion in the journal Materials Science and Engineering: A, Vol. 705, in 2017. The TiAl alloy containing Mo (0.85 wt.%) and Y (0.23 wt.%) was hot isostatically pressed at 1250°C / 175 MPa for 4 hours, and then extruded. The extrusion treatment was as follows: extrusion temperature 1300°C and extrusion ratio 9, and finally heat treated at 1350°C. The yield strength, tensile strength and fracture strain of the TiAl alloy prepared by this process at 800°C were approximately 538.3 MPa, 594.1 MPa and 4.2%, respectively.

[0053] Compared with Comparative Example 2, the present invention omits the addition of precious metal elements such as Mo and Y (alloy content is 1.08wt.%) and cumbersome processing processes such as high-temperature static pressing, extrusion and heat treatment. As a result, the yield strength, tensile strength and fracture strain of the alloy obtained by the present invention are still significantly better than those of the alloy obtained in Comparative Example 2 when the use temperature is equal to or higher than that of Comparative Example 2 (800°C). Compared with Comparative Example 2, the addition amount of nanoparticles in the present invention is controlled to be less than 0.8% (lower than Comparative Example 2) and the addition of precious metals such as Mo and Y is also avoided. The preparation process is simple and the cost is low, and the present invention achieves the simultaneous improvement of alloy strength and plasticity under high temperature conditions. The specific analysis is as follows:

[0054] The yield strength, ultimate tensile strength and fracture strain of the nano-ceramic particle reinforced titanium-aluminum alloy 1 with excellent high temperature performance prepared in Example 1 of the present invention at 800°C are 550.6MPa, 599.4MPa and 25.5%, respectively, which are increased by 12.3MPa, 5.3MPa and 21.3% respectively compared with the titanium-aluminum alloy of Comparative Example 2, and the improvement ratios are 2.3%, 0.9% and 507.1%, respectively. Therefore, the high temperature mechanical properties of the nano-ceramic particle reinforced titanium-aluminum alloy 1 with excellent high temperature performance obtained in this embodiment are significantly better than those of the titanium-aluminum alloy obtained in Comparative Example 2.

[0055] The yield strength, ultimate tensile strength and fracture strain of the nano-ceramic particle reinforced titanium-aluminum alloy 2 with excellent high temperature performance prepared in Example 2 of the present invention at 810°C (higher than the application temperature of Comparative Example 2) are 567.2MPa, 623.7MPa and 24.0%, respectively, which are increased by 28.9MPa, 29.6MPa and 19.8% respectively compared with the titanium-aluminum alloy of Comparative Example 2, and the improvement ratios are 5.4%, 5.0% and 471.4%, respectively. Therefore, the high temperature mechanical properties of the nano-ceramic particle reinforced titanium-aluminum alloy 2 with excellent high temperature performance obtained in this embodiment are significantly better than those of the titanium-aluminum alloy obtained in Comparative Example 2.

[0056] The yield strength, ultimate tensile strength and fracture strain of the nano-ceramic particle reinforced titanium-aluminum alloy 3 with excellent high temperature performance prepared in Example 3 of the present invention at 820°C (higher than the application temperature of Comparative Example 2) are 558.9MPa, 615.0MPa and 22.8%, respectively, which are 20.6MPa, 20.9MPa and 18.6% higher than those of the titanium-aluminum alloy of Comparative Example 2, and the improvement ratios are 3.8%, 3.5% and 442.9%, respectively. Therefore, the high temperature mechanical properties of the nano-ceramic particle reinforced titanium-aluminum alloy 3 with excellent high temperature performance obtained in this embodiment are significantly better than those of the titanium-aluminum alloy obtained in Comparative Example 2.

[0057] In addition, the component ratios and process parameters used in the embodiments of the present invention are different, and the microstructure size and process parameters obtained in each embodiment are different. The higher the component content, the better the performance. It can be concluded that the excellent effect obtained by the present invention is not determined by a single component, ratio or process parameter, but by the synergistic regulation of component interactions, component ratios, processes and process parameters, and the significant improvement effect of the present invention can only be achieved within the scope of protection of the claims of the present invention.

[0058] Table 1 Comparison of high temperature mechanical properties between the examples and the comparative examples

[0059]

[0060] Compared with the comparative example and the prior art, the present invention omits the addition of precious metal elements, high temperature and high pressure heat treatment process, high temperature extrusion, solid solution and aging. Under the application temperature conditions equivalent to or higher than the prior art, the alloy microstructure obtained by the present invention is a uniform lamellar structure, and the size is much smaller than the alloy obtained by the comparative example and the prior art; the titanium aluminum alloy obtained by the present invention contains uniformly distributed nano-TiB 2 +NbB 2 Ceramic particles, the particle size of nano-ceramic particles is 30-400 nanometers. The nano-particles are evenly distributed and the volume fraction can be effectively controlled, which breaks the problem of significant strength drop of existing alloys under high temperature conditions. The alloy obtained by the present invention can not only maintain high strength under high temperature conditions, but also maintain high plasticity, save raw materials and simplify the process, and can achieve stable industrial production. In summary: the best performance of the alloy obtained by the present invention is achieved by the synergistic control of component interaction, component ratio, process and process parameters, and only within the protection scope of the claims of the present invention can the best technical effect be achieved.

Claims

1. Nano-ceramic particle reinforced titanium aluminum alloy with excellent high temperature performance, characterized in that: Its preparation method comprises the following steps: Step 1: ball milling Ti powder, Nb powder and B powder at a molar ratio of 1:1:4-4.5 to obtain a first mixed powder, wherein the ball milling time is 6-9 hours, the rotation speed is 40-70 rpm, the particle size range of Ti powder is 10-40 μm, the particle size range of Nb powder is 20-70 μm, and the particle size of B powder is 0.1-1.5 μm; Step 2: Mix the first mixed powder prepared in step 1 with Ti with a particle size of 50-140 μm. 48 Al 48 The Cr2Nb2 pre-alloyed powder is subjected to ball milling and mixing treatment according to a mass ratio of 9-15:1, 4-8:1 and 2-6:1 to obtain the second, third and fourth mixed powders, respectively. The ball milling and mixing treatment takes 6-10 hours and the ball milling speed is 40-80 rpm. Step 3: Arrange the second, third and fourth mixed powders obtained in step 2 in sequence on a titanium thin strip in a mass ratio of 1-2:1-2:6-8 and package them to obtain a continuous mixed powder titanium column; Step 4: After the TiAl alloy is subjected to vacuum induction melting treatment, the continuous mixed powder titanium cylinder obtained in step 3 is added, the mass ratio of the continuous mixed powder titanium cylinder to the TiAl alloy is 0.5% to 0.8%:1, after the continuous mixed powder titanium cylinder is melted, it is kept warm for 4-10 minutes to generate nano ceramic particles and evenly distribute them, and then cast to obtain nano ceramic particle reinforced titanium aluminum alloy with excellent high temperature performance, the vacuum induction melting treatment is: under argon protection, start heating with a power of 3-10kW, increase by 5-8kW every 3-7 minutes until the alloy is completely melted, and then keep warm for 3-7 minutes, according to mass percentage, the TiAl alloy components include: Al: 33.0-34.5wt.%; Cr: 2.3-2.6wt.%; Nb: 4.7-5.1wt.%; the rest is Ti; The microstructure of the nano-ceramic particle reinforced titanium-aluminum alloy with excellent high-temperature performance is a lamellar structure with an average size of ≤122μm. The internal structure contains uniformly distributed nano-ceramic particles with a particle size of 30-400 nanometers. At ≥800°C, the yield strength, tensile strength and fracture strain of the nano-ceramic particle reinforced titanium-aluminum alloy with excellent high-temperature performance are ≥550.6MPa, ≥599.4MPa and ≥22.8% respectively.

2. The nano-ceramic particle reinforced titanium aluminum alloy with excellent high temperature performance according to claim 1, characterized in that: As described in step 1, the particle size range of Ti powder is 15-30 μm, the particle size range of Nb powder is 25-50 μm, and the particle size of B powder is 0.2-1.0 μm.

3. The nano-ceramic particle reinforced titanium aluminum alloy with excellent high temperature performance according to claim 1, characterized in that: The ball milling mixing treatment time in step 2 is 7-9 hours, and the ball milling speed is 50-70 rpm.

4. The nano-ceramic particle reinforced titanium aluminum alloy with excellent high temperature performance according to claim 1, characterized in that: The vacuum induction melting process described in step 4 is as follows: start heating at 5-8 kW power under argon protection, increase the power by 5.5-7 kW every 4-6 minutes until the alloy is completely melted, and then keep warm for 4-6 minutes.

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