Preparation method and application of high electron emission threshold titanium alloy

Abstract

The invention discloses a preparation method and application of a titanium alloy with a high electron emission threshold, and the preparation method comprises the following steps: S1, mixing Ti metal raw materials and Mo metal raw materials, and then melting and forming them under a protective atmosphere to obtain a cast alloy; the molar content of the Mo metal raw materials in all metal raw materials is 10%-20%; S2, placing the cast alloy at a temperature of 500°C for preheat treatment and then placing it at a temperature of 1000-1200°C for heat treatment, and cooling to obtain a titanium alloy with a high electron emission threshold. The present invention forms a TiMo alloy with a relatively dense organizational structure by smelting and heat treatment processes through Mo doping Ti, and optimizes the Ti field electron emission characteristics.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy preparation, and in particular to a preparation method of a high electron emission threshold titanium alloy and application thereof. Background Art

[0002] RF breakdown is a key factor restricting the performance of high-gradient acceleration structures and high-power microwave generators. A large number of studies have shown that the initial field-induced electron emission of the material is the main cause of the RF breakdown phenomenon. Ti is widely used in high-power microwave generators due to its low density and high electron emission threshold. However, as high-power microwave generators develop towards high frequency and high power, the electric field intensity in the RF cavity is significantly increased, resulting in more serious field-induced electron emission and RF breakdown problems of Ti.

[0003] In order to effectively suppress RF breakdown and improve microwave output performance, increasing the field electron emission threshold of Ti has become a feasible strategy. At present, alloying doping is regarded as a potential path to improve the electron emission threshold of Ti, but the selection and proportion of alloy doping elements are still unclear, and the adjustment strategy and method of alloy microstructure are not yet mature. In the current existing technical solutions, titanium alloys doped with other elements are prepared by powder metallurgy and sintering process. However, since the materials prepared by powder metallurgy have large pores and are not dense, they are porous materials and do not have a good electron emission threshold, making them difficult to use as RF cavity materials. In addition, after the Ti alloy is doped with elements, the microstructure of some alloys will show signs of precipitation of the second phase or uneven distribution of elements, and the field electron emission phenomenon of Ti cannot be effectively suppressed. This technical bottleneck not only limits the further improvement of the Ti emission threshold, but also restricts the development and application of more efficient and stable RF cavity materials and field electron emission devices. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a titanium alloy with a high electron emission threshold and its application. By doping Ti with Mo element and heat treatment process, the technical problem of low field electron emission threshold of Ti is optimized, providing key material support for high-power microwave devices.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for preparing a high electron emission threshold titanium alloy comprises the following steps:

[0007] S1. Mixing Ti metal raw material and Mo metal raw material and then melting and forming them in a protective atmosphere to obtain a cast alloy; the molar content of the Mo metal raw material in all metal raw materials is 10%-20%;

[0008] S2. The cast alloy is placed in a heat treatment at a temperature of 1000-1200° C., and after cooling, a high electron emission threshold titanium alloy is obtained.

[0009] As a further improvement to the above technical solution:

[0010] Step S1 includes the following steps:

[0011] A1. Wash and dry the Ti metal raw material and the Mo metal raw material;

[0012] A2, mixing the dried Ti metal raw material and the Mo metal raw material and placing them in a vacuum arc melting furnace, introducing a protective atmosphere to melt the metal raw materials to obtain a smelted alloy;

[0013] A3. The smelted alloy is subjected to suction casting to obtain a Ti-Mo cast alloy.

[0014] Step A2 includes the following steps: firstly, pre-melting the metal raw material with current I1 to make the metal raw material initially fused, and then deep melting with current I2 to obtain a smelted alloy that satisfies I1<I2.

[0015] The number of pre-smelting is 1-2 times; the number of deep smelting is 1-2 times.

[0016] The pre-smelting or deep smelting is carried out under stirring conditions.

[0017] Satisfies I1=200-300 A, I2=450-550A.

[0018] The gas pressure during the smelting (including pre-smelting and deep smelting) is 0.03-0.05Mpa; the protective atmosphere is argon or inert gas.

[0019] The smelted alloy is first preheated with a current I3 to make the alloy liquid, and then the alloy liquid is made to flow into a forming mold with a current I4 and cooled to obtain a Ti-Mo cast alloy, satisfying I3<I4.

[0020] In step S2, the heat treatment includes the following steps: heating to 400-600°C at a heating rate of 5-10°C / min for preheating for 20-60min, and then heating to 1000-1200°C at a heating rate of 5-10°C / min for insulation for 20-48h. Preheating and insulation treatment facilitate further homogenization of the alloy structure.

[0021] As a general inventive concept, the present invention also provides an application of the method for preparing the high electron emission threshold titanium alloy in preparing radio frequency cavity materials.

[0022] The emission threshold is an important indicator for evaluating the difficulty of field-induced electron emission from the cathode. The higher the emission threshold, the more difficult it is for the sample to generate field-induced electron emission, that is, the higher the required loading voltage is at the same emission current. The "high electron emission threshold" in this text refers to a high threshold electric field, which is the electric field strength corresponding to the stable cathode emission current (1nA) that the detection equipment can measure.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention discloses a method for preparing a titanium alloy with a high electron emission threshold. First, Mo is a transition metal element with a high work function and good electrical conductivity. The addition of the Mo element can increase the work function of the Ti matrix, thereby increasing the field emission threshold of Ti. Secondly, Mo, as a β-phase stabilizing element, can form a continuous solid solution with Ti, so that the Ti-Mo alloy forms a single stable phase structure, effectively avoiding the concentrated emission of electrons in a specific phase. Based on this, the present invention controls the proportion of Mo doped Ti matrix, adopts a heat treatment process to improve the microstructure of the alloy, and obtains a TiMo alloy with a single phase structure and uniform element distribution, thereby optimizing the Ti field electron emission characteristics, and the threshold electric field strength reaches 360-400 kV / cm, breaking through the performance bottleneck of traditional Ti materials in high-power microwave devices, and providing key material support for the further development of radio frequency microwave technology. In addition, the preparation method of the present invention is simple and easy to implement and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a process flow chart of the present invention.

[0026] Figure 2 This is a graph showing the XRD test results of the cast Ti85Mo15 alloy in Example 1 of the present invention.

[0027] Figure 3 This is a graph showing the electron microscope and energy spectrum test results of the cast Ti85Mo15 alloy in Example 1 of the present invention. Figure 3 (a)-3(b) are the test results of electron microscope. Figure 3 (c)-3(e) are the energy spectrum test results.

[0028] Figure 4 This is a graph showing the XRD test results of the Ti85Mo15 alloy after heat treatment in Example 1 of the present invention.

[0029] Figure 5 It is a graph showing the electron microscope and energy spectrum test results of the Ti85Mo15 alloy after heat treatment in Example 1 of the present invention. Figure 5 (a) is the electron microscope test result. Figure 5 (b)-5(d) are the energy spectrum test results.

[0030] Figure 6 It is a field emission test result diagram of the heat-treated Ti85Mo15 alloy and unalloyed Ti in Example 1 of the present invention.

[0031] Figure 7 This is a graph showing the XRD test results of the cast Ti90Mo10 alloy in Example 2 of the present invention.

[0032] Figure 8 It is a graph showing the electron microscope and energy spectrum test results of the cast Ti90Mo10 alloy in Example 2 of the present invention. Figure 8 (a)-8(b) are the test results of electron microscope. Figure 8 (c)-8(e) are the energy spectrum test results.

[0033] Fig. 9 This is a graph showing the XRD test results of the Ti90Mo10 alloy after heat treatment in Example 2 of the present invention.

[0034] Fig.10 It is a graph showing the electron microscope and energy spectrum test results of the Ti90Mo10 alloy after heat treatment in Example 2 of the present invention. Fig.10 (a) is the electron microscope test result. Fig.10 (b)-10(d) are the energy spectrum test results.

[0035] Fig.11 This is a graph showing the field emission test results of the heat-treated Ti90Mo10 alloy and unalloyed Ti in Example 2 of the present invention.

[0036] Fig.12 This is a graph showing the XRD test results of the cast Ti80Mo20 alloy in Example 3 of the present invention.

[0037] Fig.13 It is a graph showing the electron microscope and energy spectrum test results of the cast Ti80Mo20 alloy in Example 3 of the present invention. Fig.13 (a)-13(b) are the test results of electron microscope. Fig.13 (c)-13(e) are the energy spectrum test results.

[0038] Fig.14 This is a graph showing the XRD test results of the Ti80Mo20 alloy after heat treatment in Example 3 of the present invention.

[0039] Fig.15 It is a graph showing the electron microscope and energy spectrum test results of the Ti80Mo20 alloy after heat treatment in Example 3 of the present invention. Fig.15 (a) is the electron microscope test result. Fig.15 (b)-15(d) are the energy spectrum test results.

[0040] Fig.16This is a graph showing the field emission test results of the heat-treated Ti80Mo20 alloy and unalloyed Ti in Example 3 of the present invention.

[0041] Fig.17 It is a graph showing the field emission performance test results of the heat-treated titanium alloy and unalloyed Ti in Comparative Examples 1 and 2 of the present invention.

[0042] Fig.18 Photographs of titanium alloy casting in Comparative Example 3 and Example 1 of the present invention. Fig.18 (a) is Comparative Example 3. Fig.18 (b) is Example 1.

[0043] Fig.19 Backscattering image of the titanium alloy surface after heat treatment in Comparative Example 4 of the present invention. DETAILED DESCRIPTION

[0044] The present invention will be described in further detail below. Unless otherwise specified, the instruments or materials used in the present invention are commercially available.

[0045] Example 1

[0046] like Figure 1 As shown, a method for preparing a titanium alloy with a high electron emission threshold in this embodiment comprises the following steps:

[0047] (1) Raw material preparation: Weigh Ti metal particles and Mo metal particles in a molar ratio of 85:15, immerse the weighed Ti-Mo metal raw materials in water and alcohol solutions for ultrasonic cleaning for 30 minutes, and then dry them for later use. The present invention uses metal particles as raw materials instead of powders. The metal particles are larger in size than the powders, which can avoid scattering during subsequent vacuum melting and vacuum extraction.

[0048] (2) Melting of alloy. First, the prepared Ti and Mo raw materials are placed in a vacuum arc melting furnace. Then, the melting furnace is evacuated by using a mechanical pump and a molecular pump. When the vacuum degree reaches 3×10 -3 Pa, and then high-purity argon is filled to 0.05MPa. The Ti ingot in the smelting furnace absorbs the residual gas in the furnace through high-purity melting, and then the smelting of Ti-Mo alloy begins. In the initial stage, 250 A current is used to pre-melt the raw materials, and the raw materials are initially fused after 1-2 times of melting, cooling and turning. Subsequently, deep melting is carried out with 500 A current, and the melting process is repeated 1-2 times to ensure that the high-melting point raw materials are fully dissolved. At the same time, the electromagnetic stirring function is started in time to promote uniform melting of the raw materials.

[0049] (3) Suction casting of alloy. After smelting, conventional suction casting process is used for suction casting. That is, the uniformly smelted alloy is moved to the suction casting crucible in the smelting furnace with a small shovel, and a small current is added for preheating. After preheating to a molten state, the current is increased rapidly to make the alloy melt flow into the suction casting mold. After cooling for about 10 minutes, it is taken out to obtain the cast Ti85Mo15 alloy.

[0050] The XRD and surface energy spectrum test results of the cast Ti85Mo15 alloy obtained in this embodiment are as follows: Figure 2 and Figure 3 As shown. Figure 2 It can be seen that the original Ti metal is a close-packed hexagonal structure, and the crystal structure of the cast Ti85Mo15 alloy is transformed from the close-packed hexagonal structure of the original Ti to a body-centered cubic structure. Figure 3 It can be seen that dendrites appear on the surface of the cast Ti85Mo15 and the element distribution is not uniform.

[0051] (4) Packaging of cast alloy: The cast Ti85Mo15 alloy was transferred into a quartz tube, and then the air in the quartz tube was extracted with a mechanical pump. After the vacuum reached 1 Pa, the quartz tube was packaged with a flame gun.

[0052] (5) Heat treatment of cast alloy. The packaged quartz tube was transferred to a muffle furnace, heated to 500°C at a rate of 5°C / min and kept at this temperature for 30 min, and then heated to 1000°C at a rate of 10°C / min and kept at this temperature for 24 h. After the insulation was completed, the sample was cooled to room temperature in the furnace and taken out of the quartz tube to obtain the heat-treated Ti85Mo15 alloy.

[0053] The XRD and electron microscope test results of the heat-treated Ti85Mo15 alloy in this embodiment are as follows: Figure 4 and Figure 5 As shown. Figure 4 It can be seen that the sample still maintains a body-centered cubic structure. Figure 5 The electron microscopy and energy spectrum test results show that the dendrites on the alloy surface disappear after heat treatment, and the Ti and Mo elements are evenly distributed.

[0054] An application of the preparation method of the titanium alloy with high electron emission threshold of the present embodiment in the preparation of radio frequency cavity materials, the titanium alloy with high electron emission threshold prepared in the present embodiment is used as a radio frequency cavity material, and the Ti85Mo15 alloy obtained in the present embodiment is compared with unalloyed Ti (referring to pure Ti prepared by the same smelting and suction casting process as in the present embodiment, excluding the Mo element) in field emission test. The test results are as follows Figure 6As shown in the figure. From the test results, it can be seen that the threshold electric field strength of field electron emission of Ti85Mo15 alloy and Ti is 380 kV / cm and 280 kV / cm respectively, and the threshold electric field strength is increased by 35.7%. It can be seen that the doping of 15 at% Mo element can effectively improve the field electron emission characteristics of Ti.

[0055] Example 2

[0056] A method for preparing a titanium alloy with a high electron emission threshold in this embodiment comprises the following steps:

[0057] (1) Raw material preparation: Weigh Ti metal particles and Mo metal particles at a molar ratio of 90:10, immerse the weighed Ti-Mo metal raw materials in water and alcohol solution successively for ultrasonic cleaning for 30 min, and then dry them for later use;

[0058] (2) Melting of alloy. First, the prepared Ti and Mo raw materials are placed in a vacuum arc melting furnace. Then, the melting furnace is evacuated by using a mechanical pump and a molecular pump. When the vacuum degree reaches 3×10 -3 Pa, and then high-purity argon is filled to 0.05MPa. The Ti ingot in the smelting furnace absorbs the residual gas in the furnace through high-purity melting, and then the smelting of Ti-Mo alloy begins. In the initial stage, 250 A current is used to pre-melt the raw materials, and the raw materials are initially fused after 1-2 times of melting, cooling and turning. Subsequently, deep melting is carried out with 500 A current, and the melting process is repeated 1-2 times to ensure that the high-melting point raw materials are fully dissolved. At the same time, the electromagnetic stirring function is started in time to promote uniform melting of the raw materials.

[0059] (3) Suction casting of alloy. After smelting, conventional suction casting process is used for suction casting. That is, the uniformly smelted alloy is moved to the suction casting crucible in the smelting furnace with a small shovel, and a small current is added for preheating. After preheating to a molten state, the current is quickly increased to make the alloy melt flow into the suction casting mold. After it cools for about 10 minutes, it is taken out to obtain the cast Ti90Mo10 alloy.

[0060] The XRD and surface energy spectrum test results of the cast Ti90Mo10 alloy obtained in this example are as follows: Figure 7 and Figure 8 As shown. Figure 7 It can be seen that the crystal structure of the cast Ti90Mo10 alloy is transformed from the close-packed hexagonal structure of the original Ti to the body-centered cubic structure (the materials used in each embodiment and comparative example of the present invention are the same as those in Example 1, and the original Ti metal is a close-packed hexagonal structure). Figure 8 It can be seen that dendrites appear on the surface of the cast Ti90Mo10 alloy and the element distribution is not uniform.

[0061] (4) Packaging of cast alloy: The cast Ti90Mo10 alloy was transferred into a quartz tube, and then the air in the quartz tube was extracted with a mechanical pump. After the vacuum reached 1 Pa, the quartz tube was packaged with a flame gun.

[0062] (5) Heat treatment of cast alloy. The packaged quartz tube was transferred to a muffle furnace, heated to 500°C at a rate of 5°C / min and kept at this temperature for 30 min, and then heated to 1000°C at a rate of 10°C / min and kept at this temperature for 24 h. After the insulation was completed, the sample was cooled to room temperature in the furnace and taken out of the quartz tube to obtain the heat-treated Ti90Mo10 alloy.

[0063] The XRD and electron microscope test results of the Ti90Mo10 alloy after heat treatment in this embodiment are as follows: Fig. 9 and Fig.10 As shown. Fig. 9 It can be seen that after heat treatment, the crystal structure of Ti90Mo10 changes from a single BCC structure to a BCC / HCP structure, in which the HCP structure accounts for a small proportion, indicating that after heat treatment, a small amount of HCP structure precipitates during the cooling process. Fig.10 The electron microscopy and energy spectrum test results show that the dendrites on the alloy surface disappear after heat treatment, and the Ti and Mo elements are evenly distributed.

[0064] An application of the preparation method of the titanium alloy with high electron emission threshold of the present embodiment in the preparation of radio frequency cavity materials, the titanium alloy with high electron emission threshold prepared in the present embodiment is used as a radio frequency cavity material, and the Ti90Mo10 alloy obtained in the present embodiment is compared with the unalloyed Ti in field emission test. The test results are as follows Fig.11 As shown in the figure. From the test results, it can be seen that the threshold electric field strength of field electron emission of Ti90Mo10 alloy and unalloyed Ti is 360 kV / cm and 280 kV / cm respectively, and the threshold electric field strength is increased by 28.6%. It can be seen that the doping of 10at% Mo element can effectively improve the field electron emission characteristics of Ti.

[0065] Example 3

[0066] A method for preparing a titanium alloy with a high electron emission threshold in this embodiment comprises the following steps:

[0067] (1) Raw material preparation: Weigh Ti metal particles and Mo metal particles at a molar ratio of 80:20, immerse the weighed Ti-Mo metal raw materials in water and alcohol solution successively for ultrasonic cleaning for 30 min, and then dry them for later use;

[0068] (2) Melting of alloy. First, the prepared Ti and Mo raw materials are placed in a vacuum arc melting furnace. Then, the melting furnace is evacuated by using a mechanical pump and a molecular pump. When the vacuum degree reaches 3×10 -3 Pa, and then high-purity argon is filled to 0.05MPa. The Ti ingot in the smelting furnace absorbs the residual gas in the furnace through high-purity melting, and then the smelting of Ti-Mo alloy begins. In the initial stage, 250 A current is used to pre-melt the raw materials, and the raw materials are initially fused after 1-2 times of melting, cooling and turning. Subsequently, deep melting is carried out with 500 A current, and the melting process is repeated 1-2 times to ensure that the high-melting point raw materials are fully dissolved. At the same time, the electromagnetic stirring function is started in time to promote uniform melting of the raw materials.

[0069] (3) Suction casting of alloy. After smelting, conventional suction casting process is used for suction casting. That is, the uniformly smelted alloy is moved to the suction casting crucible in the smelting furnace with a small shovel, and a small current is added for preheating. After preheating to a molten state, the current is quickly increased to make the alloy melt flow into the suction casting mold. After it cools for about 10 minutes, it is taken out to obtain the cast Ti80Mo20 alloy.

[0070] The XRD and surface energy spectrum test results of the cast Ti80Mo20 alloy obtained in this example are as follows: Fig.12 and Fig.13 As shown. Fig.12 It can be seen that the crystal structure of the cast Ti80Mo20 alloy is completely transformed from a close-packed hexagonal structure to a body-centered cubic structure. Fig.13 The microstructure characteristics of the cast Ti80Mo20 alloy sample are revealed, and the dendrite structure is clearly visible. With the increase of molybdenum (Mo) element content, the dendrite size increases significantly and the degree of element segregation increases.

[0071] (4) Packaging of cast alloy: The cast Ti80Mo20 alloy was transferred into a quartz tube, and then the air in the quartz tube was extracted with a mechanical pump. After the vacuum reached 1 Pa, the quartz tube was packaged with a flame gun.

[0072] (5) Heat treatment of cast alloy. The packaged quartz tube was transferred to a muffle furnace, heated to 500°C at a rate of 5°C / min and kept at this temperature for 30 min, and then heated to 1000°C at a rate of 10°C / min and kept at this temperature for 24 h. After the insulation was completed, the sample was cooled to room temperature in the furnace and taken out of the quartz tube to obtain the heat-treated Ti80Mo20 alloy.

[0073] The XRD and electron microscope test results of the Ti80Mo20 alloy after heat treatment in this embodiment are as follows: Fig.14 and Fig.15 As shown. Fig.14It can be seen that the crystal structure of Ti80Mo20 alloy after heat treatment remains BCC structure, and the large addition of Mo element enhances the microstructural stability of the alloy. Fig.12 The electron microscopy and energy spectrum test results show that the dendrites on the alloy surface disappear after heat treatment, and the Ti and Mo elements are evenly distributed.

[0074] An application of the preparation method of the titanium alloy with high electron emission threshold of the present embodiment in the preparation of radio frequency cavity materials, the titanium alloy with high electron emission threshold prepared in the present embodiment is used as a radio frequency cavity material, and the Ti80Mo20 alloy obtained in the present embodiment is compared with the unalloyed Ti in field emission test. The test results are as follows Fig.16 As shown in the figure. From the test results, it can be seen that the threshold electric field strength of field electron emission of Ti80Mo20 alloy and unalloyed Ti is 400 kV / cm and 280 kV / cm respectively, and the threshold electric field strength is increased by 42.8%. It can be seen that the doping of 20at% Mo element can effectively improve the field electron emission characteristics of Ti.

[0075] The Ti-Mo alloy of the present invention exhibits significant advantages. When the Mo doping amount is 10at%, the field electron emission threshold electric field strength increases from the original 280 kV / cm to 360 kV / cm, an increase of 28.6%; when the Mo doping amount is 15at%, the threshold electric field strength is further increased to 380 kV / cm, an increase of 35.7%; when the Mo doping amount is 20at%, the threshold electric field strength is further increased to 400 kV / cm, an increase of 42.8% over the original Ti. After heat treatment, the uniformity of the alloy microstructure is significantly improved, and the body-centered cubic (BCC) stable structure is maintained.

[0076] Comparative Example 1

[0077] The preparation method of the Ti98Mo2 titanium alloy in this comparative example is substantially the same as that of Example 1, except that the content of Mo in the alloy is 2 at %.

[0078] Comparative Example 2

[0079] The preparation method of the Ti95Mo5 titanium alloy in this comparative example is substantially the same as that of Example 1, except that the content of Mo in the alloy is 5 at %.

[0080] If the Mo content is less than 10%, the measured field emission threshold is lower than that of unalloyed Ti (such as Fig.17As shown in the figure), the emission threshold of the Ti98Mo2 titanium alloy in comparative example 1 is 190 kV / cm, and the electron emission threshold of the Ti95Mo5 titanium alloy in comparative example 2 is 220 kV / cm, both of which are lower than 280 kV / cm of the unalloyed Ti, indicating that too low Mo content cannot effectively improve the field electron emission characteristics of Ti.

[0081] Comparative Example 3

[0082] The preparation method of the titanium alloy in this comparative example is substantially the same as that of Example 1, except that the content of Mo in the alloy is 25 at %.

[0083] Fig.18 shows a photo of the titanium alloy after forming, Fig.18 (a) is that of Comparative Example 1, Fig.18 (b) is Example 1. Since the melting points of Mo (2623°C) and Ti (1668°C) are quite different, when the proportion of Mo in the alloy is too high (greater than 20%), the viscosity of the alloy melt will be high and the fluidity will be reduced. The high viscosity melt will be difficult to fill the mold smoothly during the casting process, and defects will be easily formed, making it difficult to form and use ( Fig.18 (as shown in (a)).

[0084] Comparative Example 4

[0085] The preparation method of the titanium alloy in this comparative example is substantially the same as that in Example 1, except that the heat treatment temperature is different: the temperature is increased to 500°C at a rate of 5°C / min and kept at that temperature for 30 minutes, and then the temperature is increased to 950°C at a rate of 10°C / min and kept at that temperature for 24 hours.

[0086] from Fig.19 From the backscattered photos shown, it can be seen that the surface of the alloy in comparative example 4 is still unevenly distributed. This is because the β phase temperature zone of the TiMo binary phase diagram should be higher than 880°C, and Mo has a larger atomic number and a lower diffusion coefficient (0.6×10 -10 cm 2 / s) is low, so the heat treatment temperature should not be too low.

[0087] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a titanium alloy with a high electron emission threshold, characterized in that: The following steps are involved: S1. Mixing Ti metal raw material and Mo metal raw material and then melting and forming them in a protective atmosphere to obtain a cast alloy; the molar content of the Mo metal raw material in all metal raw materials is 10%-20%; S2. The cast alloy is placed in a heat treatment at a temperature of 1000-1200° C., and after cooling, a high electron emission threshold titanium alloy is obtained.

2. The method for preparing a titanium alloy with a high electron emission threshold according to claim 1, characterized in that: Step S1 includes the following steps: A1. Wash and dry the Ti metal raw material and the Mo metal raw material; A2, mixing the dried Ti metal raw material and the Mo metal raw material and placing them in a vacuum arc melting furnace, introducing a protective atmosphere to melt the metal raw materials to obtain a smelted alloy; A3. The smelted alloy is subjected to suction casting to obtain a Ti-Mo cast alloy.

3. The method for preparing a high electron emission threshold titanium alloy according to claim 2, characterized in that: Step A2 includes the following steps: firstly pre-melting the metal raw material with current I1 to initially fuse the metal raw material, and then deep-melting with current I2 to obtain a smelted alloy that satisfies I1<I2.

4. The method for preparing a titanium alloy with a high electron emission threshold according to claim 3, characterized in that: The number of pre-smelting is 1-2 times; the number of deep smelting is 1-2 times.

5. The method for preparing a titanium alloy with a high electron emission threshold according to claim 3, characterized in that: The pre-smelting or deep smelting is carried out under stirring conditions.

6. The method for preparing a titanium alloy with a high electron emission threshold according to claim 3, characterized in that: Satisfies I1=200-300 A, I2=450-550A.

7. The method for preparing a titanium alloy with a high electron emission threshold according to claim 2, characterized in that: In step A2, the gas pressure during smelting is 0.03-0.05Mpa; the protective atmosphere is argon or inert gas.

8. The method for preparing a titanium alloy with a high electron emission threshold according to claim 2, characterized in that: In step A3, the smelted alloy is first preheated with a current I3 to make the alloy molten, and then the molten alloy is made to flow into a forming mold with a current I4 and cooled to obtain a Ti-Mo cast alloy, satisfying I3<I4.

9. The method for preparing a titanium alloy with a high electron emission threshold according to any one of claims 1 to 8, characterized in that: In step S2, the heat treatment includes the following steps: heating to 400-600°C at a heating rate of 5-10°C / min for preheating for 20-60min, and then heating to 1000-1200°C at a heating rate of 5-10°C / min for keeping warm for 20-48h.

10. Use of the method for preparing a high electron emission threshold titanium alloy according to any one of claims 1 to 9 in preparing radio frequency cavity materials.

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