Titanium-aluminum alloy prepared by one-step method of magnesium-aluminum reduction of titanium tetrachloride and preparation method thereof

Abstract

The present application relates to the technical field of metal materials, in particular to a titanium-aluminum alloy prepared by one-step method of magnesium-aluminum reduction of tetrachloride and a preparation method thereof.The preparation method comprises the following steps: preparing a molten magnesium-aluminum melt in an argon environment; under stable pressure and low-frequency electromagnetic stirring, adding metal chlorides into the magnesium-aluminum melt by controlling the reaction temperature and the feeding rate, preparing a titanium-aluminum alloy sponge mixture through a thermal reduction reaction, and stopping feeding; the metal chlorides comprise titanium tetrachloride and at least one alloying element chloride; removing the unreacted reducing agent magnesium and byproduct magnesium chloride from the titanium-aluminum alloy sponge mixture through vacuum distillation, and obtaining a pure multi-element titanium-aluminum alloy after argon filling and natural cooling.The present application not only solves the problems of poor uniformity of alloying elements and forced complication of the process flow, but also achieves micron-level uniform distribution of elements in terms of composition control.

Description

Technical Field

[0001] This invention relates to the field of metal materials technology, specifically to a one-step method for preparing titanium-aluminum alloys using magnesium-aluminum reduction tetrachloride, and the titanium-aluminum alloys prepared using this method. Background Technology

[0002] Titanium-aluminum alloys, possessing both the high strength and corrosion resistance of titanium and the low density and good thermal conductivity of aluminum, show broad application prospects in high-end fields such as aerospace, automotive manufacturing, and medical devices. With the ever-increasing industrial demand for high-performance lightweight materials, the preparation process of titanium-aluminum alloys has become a research hotspot.

[0003] Currently, the mainstream preparation methods for titanium-aluminum alloys include vacuum arc melting, electron beam melting, and powder metallurgy. Vacuum arc melting requires multiple melting processes to ensure compositional uniformity, resulting in high energy consumption, long production cycles, and difficulty in precisely controlling the content of trace elements in the alloy. While electron beam melting can achieve high purification effects, it requires large equipment investment and has high operating costs, making it unsuitable for large-scale production. Although powder metallurgy can reduce alloy segregation, the powder preparation and sintering processes easily introduce impurities, and the complex procedures lead to high production costs.

[0004] Furthermore, traditional processes often employ a stepwise reduction method to prepare titanium-aluminum alloys. This involves first reducing TiCl4 with Mg to obtain sponge titanium, then crushing the sponge titanium and adding aluminum and other alloying elements in a specific ratio, finally pressing the mixture onto electrodes and melting it to obtain the final titanium-aluminum alloy. This stepwise process is not only cumbersome but also results in raw material loss due to the transfer and secondary processing of intermediate products, reducing utilization rates. It also increases the possibility of segregation and localized structural defects in the titanium-aluminum alloy, making it difficult to guarantee the performance stability of the final alloy product. To address the shortcomings of the above processes, Chinese patent CN115011829A discloses a method for preparing titanium-aluminum alloys, the titanium-aluminum alloys themselves, and their applications. However, the titanium-aluminum alloys prepared by this method are binary titanium-aluminum alloys, which are not practical. The room temperature plasticity, high-temperature oxidation resistance, and comprehensive mechanical properties of binary titanium-aluminum alloys cannot meet the requirements of the application environment. Typically, other functional metallic elements, usually tertiary or even quaternary alloying elements, need to be introduced during the preparation process to form tertiary or quaternary titanium-aluminum alloy systems with more optimized composition and structure. Furthermore, this method is only suitable for small-scale experiments. When producing in large furnaces, the inconsistent densities of Mg and Al can lead to Mg and Al stratification, ultimately resulting in extremely poor compositional uniformity of the entire alloy mass. Nevertheless, among the existing preparation methods, the introduction of alloying elements still faces a series of prominent problems and challenges, severely restricting the stable and efficient preparation of high-performance multi-component titanium-aluminum alloys.

[0005] When adding alloying elements such as Cr and Mn, the methods often involve directly adding pure metals or pre-forming intermediate alloys. However, due to significant differences in melting point, density, reactivity, and diffusion rate between the alloying elements and the titanium or aluminum matrix, macroscopic or microscopic segregation of the composition is easily caused during melt solidification, making it difficult to achieve atomic-level uniform distribution of the alloying elements in the matrix. This inhomogeneity can induce local enrichment of harmful brittle phases, which not only fail to effectively exert their plasticizing and strengthening effects but may also become crack initiation sites, impairing the alloy's uniformity and performance reliability.

[0006] Meanwhile, the addition of alloying elements often depends on subsequent smelting processes. This not only complicates the already lengthy process but also requires higher superheating or longer holding times to promote the dissolution of high-melting-point elements (such as Nb and Mo), significantly increasing energy consumption and production cycle. If alloying elements are added directly in solid metal form, the melting and diffusion problems of high-melting-point elements are more prominent under limited reaction time and relatively low reaction temperature, easily leading to the formation of unmelted blocks or compositional gradients. If a multi-component master alloy is prepared in advance, the process advantage of the "one-step" method is lost, and the preparation of the master alloy itself also suffers from the aforementioned uniformity problems. Furthermore, the coexistence of multiple metal raw materials may exacerbate side reactions with the reaction medium (such as MgCl2) or residual gases, leading to a decrease in alloy purity and adversely affecting the alloy's plasticity, toughness, and high-temperature performance.

[0007] In summary, existing titanium-aluminum alloy preparation technologies generally face core technical bottlenecks in achieving multi-element alloying, including poor uniformity of alloy element distribution, forced complexity of process flows, low precision in composition control, and increased risk of impurity introduction. These bottlenecks restrict the preparation of high-performance multi-element titanium-aluminum alloys and limit their industrial application. Summary of the Invention

[0008] Technical Problem: This invention proposes a one-step method for preparing titanium-aluminum alloys by magnesium-aluminum reduction tetrachloride and its preparation method. The purpose is to solve the problems that existing titanium-aluminum alloy preparation technologies generally face in achieving multi-element alloying, such as poor uniformity of alloy element distribution, forced complexity of process flow, low precision of composition control, and increased risk of impurity introduction.

[0009] Technical solution The first aspect of this invention provides a one-step method for preparing titanium-aluminum alloys using magnesium-aluminum reduction tetrachloride, comprising the following steps: S1 prepares magnesium and aluminum into a molten magnesium-aluminum liquid under an argon atmosphere; S2, under stable pressure and low-frequency electromagnetic stirring, by controlling the reaction temperature and feeding rate, adds metal chlorides to molten magnesium and aluminum, and prepares a sponge titanium-aluminum alloy mixture through thermal reduction reaction until the feeding is completed; the metal chlorides include titanium tetrachloride and at least one alloying element chloride; S3 removes unreacted reducing agent magnesium and byproduct magnesium chloride from the sponge titanium-aluminum alloy mixture through vacuum distillation, and then obtains a pure multi-element titanium-aluminum alloy after purging with argon gas and allowing it to cool naturally after exiting the furnace.

[0010] Preferably, in step S1, the amount of magnesium added is at least 1.2 times the theoretical amount required for titanium tetrachloride and alloying element chloride to be reduced to pure metal by magnesium; the amount of aluminum added is according to the required mass percentage of aluminum in the product multi-element titanium-aluminum alloy, and should meet the requirement that aluminum accounts for 2-63% of the total mass percentage in the product multi-element titanium-aluminum alloy.

[0011] Preferably, in step S2, the amount of titanium tetrachloride and alloy element chloride added is calculated as the mass of the corresponding element chloride based on the required mass percentage of each element in the product multi-element titanium-aluminum alloy.

[0012] Preferably, in step S2, the pressure is stabilized at 5-25 kPa; the operating frequency of the low-frequency electromagnetic stirrer is 0.5-20 Hz, and the output current is 300-415 A; the reaction temperature is controlled at 600-700 ℃; and the feeding rate is 2-10 kg / h.

[0013] Preferably, the vacuum distillation conditions in step S3 are: controlling the vacuum level to reach 1×10⁻⁶. -2 Pa to 5×10 -2 Pa, after distillation, the temperature inside the reactor rises to 900-1000℃.

[0014] Preferably, positive pressure is maintained inside the furnace during the natural cooling process after the furnace is unloaded in step S3.

[0015] The second aspect of this invention provides a titanium-aluminum alloy prepared according to the one-step method for preparing titanium-aluminum alloy by magnesium-aluminum reduction tetrachloride.

[0016] Beneficial effects This invention eliminates the traditional alloy manufacturing processes of refining and crushing sponge titanium raw materials, adding elemental Al, and pressing electrodes for melting, thus shortening the production cycle, avoiding material and energy losses from secondary melting, and reducing production costs. Based on the composition requirements of the target Ti-Al alloy, this invention controls the input amounts of Mg, Al, and other alloying elements. The amount of Mg input must be at least 1.2 times the theoretical amount required for TiCl4 and other chlorides to be reduced to pure metal by Mg, to ensure the completeness of the reduction reaction. Furthermore, multiple chlorides are added in precise proportions, allowing TiCl4 to react in situ with these chlorides within the molten Mg-Al alloy during the reaction. The feeding rate of the metallic chlorides is controlled to prevent excessively vigorous thermal reduction; an excess of Mg is used to avoid incomplete reduction. By melting magnesium and aluminum ingots in a medium-frequency furnace and adjusting the operating frequency and output current of the electromagnetic stirrer to generate periodically varying electromagnetic forces, the alloy liquid is driven to move in a circular motion along the inner wall of the crucible. This, coupled with vertical convection circulation, breaks down the stratification caused by density differences, ensuring uniform diffusion and dispersion of titanium atoms throughout the molten magnesium-aluminum alloy, further improving the homogeneity of the Ti-Al alloy. This method achieves a one-step preparation of multi-component titanium-aluminum alloys, avoiding problems such as localized compositional inhomogeneity found in traditional arc melting methods.

[0017] This invention not only solves the common problems of poor uniformity of alloy element distribution and forced complexity of process flow, but also achieves uniform distribution of elements at the micron level in terms of composition control, which will be an order of magnitude improvement in the performance of Ti-Al alloys and even titanium alloys. Attached Figure Description

[0018] Figure 1 This is a flowchart of the preparation method of the present invention; Figure 2 The diagrams show the Ti-Al phase diagram and Gibbs free energy curves, where A is the Ti-Al binary phase diagram and B is the Gibbs free energy curve of the main substances in the reaction process. Figure 3 SEM image of the microstructure of the titanium alloy product; Figure 4 The images show the EDS distribution of the titanium alloy product, with Ti, Al, Cr, and Nb elements at a 10 μm scale. Detailed Implementation

[0019] To further illustrate the technical means and effects of this invention, the following description, in conjunction with embodiments and accompanying drawings, provides a further explanation of the invention. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0020] This invention proposes a one-step method for preparing titanium-aluminum alloys using magnesium-aluminum reduction tetrachloride, such as... Figure 1As shown, the steps are as follows: S1 prepares magnesium and aluminum into a molten magnesium-aluminum liquid under an argon atmosphere; A predetermined amount of magnesium and aluminum ingots are placed in a reduction reactor, heated to 300-500℃, and then degassed under vacuum until the vacuum level is less than 1×10⁻⁶. -1 After purging with argon, the temperature is raised again to 700-850℃, reaching the melting points of magnesium, aluminum, and their chlorides, to ensure that the magnesium and aluminum ingots have melted into a molten magnesium-aluminum alloy. The amount of aluminum added should meet the requirement that aluminum accounts for 2-63% of the total mass of the product's multi-element titanium-aluminum alloy. The aluminum content is added according to the required mass percentage of aluminum element in the product's multi-element titanium-aluminum alloy, and the Al content should be proportioned to the mass of TiCl4 and other chlorides after reduction to pure metal, with an Al:other metal element ratio of 2-63:98-37.

[0021] This invention simultaneously adds titanium tetrachloride and at least one alloying element chloride to a magnesium-aluminum molten liquid for a reduction reaction. Due to differences in the stability and boiling point of each chloride, to avoid incomplete reduction, this invention further limits the amount of magnesium added to at least 1.2 times the theoretical amount of titanium tetrachloride and alloying element chloride required for magnesium to reduce to pure metal, thus ensuring a complete reduction reaction.

[0022] The excessive addition of Mg in this application does not affect the formation of the target product, the Ti-Al alloy, as follows: According to the Ti-Al phase diagram, as... Figure 2 As shown in Figure A, the addition amounts of raw materials TiCl4, Mg ingot, and Al ingot were calculated. To determine the reaction process and sequence in the furnace, a plot was drawn based on the calculation results from the thermodynamic calculation software HCS Chemistry 9.5. Figure 2 The possible reactions shown by B at different temperatures The change curves show that, except for the MgCl2+Al reaction, the corresponding reactions of TiCl4+Mg, TiCl4+Al, and AlCl3+Mg in the temperature range of 300-1300°C are as follows. All values ​​are negative, meaning that under suitable kinetic conditions, the reactions can proceed spontaneously under standard conditions, and the TiCl4+Mg reaction is more spontaneous than the TiCl4+Al reaction. The more negative reaction within the specified temperature range indicates that TiCl4 + Mg is more readily reacted in the reactor, becoming the dominant reaction. Following the principle of metal reduction preference, the TiCl4 + Al reaction occurs little or no. To further elucidate this process at the microscopic scale, we will analyze it later using the EET SCBLD method. Furthermore, if AlCl3 is present in the products, thermodynamic analysis shows that AlCl3 + Mg can react to form Al + MgCl2. Under conditions of excess Mg, this does not affect the formation of the target product, the Ti-Al alloy. Studies have shown that the production of AlCl3 has a certain catalytic effect on the TiCl4 + Al reaction.

[0023] S2 is prepared by adding metal chlorides to molten magnesium and aluminum under stable pressure and low-frequency electromagnetic stirring, controlling the reaction temperature at 600-700℃ and the feeding rate at 2-10kg / h. The mixture is then thermally reduced to prepare a sponge titanium-aluminum alloy. The feeding process continues until the end of the process. The metal chlorides include titanium tetrachloride and at least one chloride of an alloying element. The reduction reaction begins with the addition of a metal chloride. During the reaction, the pressure is kept stable at 5-25 kPa, the reaction temperature is 600-700℃, and the feeding rate is 2-10 kg / h. Under these conditions, TiCl4 and at least one alloying element chloride undergo a thermal reduction reaction with the molten magnesium-aluminum mixture to produce a Ti-Al alloy. When the feeding is finished, the furnace pressure is frequently increased at least 5 times within 10 minutes, and the pressure is released until white TiCl4 fumes are seen, at which point the reduction reaction ends.

[0024] The alloying element chloride is MCly (M: Nb, Cr, Mo, W, Si…; y: 1, 2, 3, 4…). After being converted into chloride according to the required proportions of other elements in Ti-Al alloys such as Ti-48Al-2Cr-2Nb, Ti-47Al-2W-0.5Si, and Ti-46Al-8Nb, it is added together with TiCl4 into the molten magnesium-aluminum alloy. Since the reduction of metal chloride by Mg is a violent exothermic reaction, when metal chloride is added to the molten magnesium-aluminum mixture, it releases a large amount of heat instantly, which can lead to local overheating, titanium particles settling and agglomerating, and uneven distribution of alloying elements. Therefore, the reactor of this invention is equipped with a low-frequency electromagnetic stirring device. The low-frequency electromagnetic stirring operates at a frequency of 0.5-20Hz and outputs a current of 300-415A to generate periodically changing electromagnetic force, driving the molten liquid to move in a circular motion along the inner wall of the reactor. This is accompanied by upper and lower convection circulation to break the stratification trend caused by density differences, thereby ensuring the uniform distribution of Al in the reactor and thus ensuring the compositional uniformity of the final Ti-Al alloy agglomerate. At the same time, it is beneficial to the aggregation and flotation of the low-density byproduct MgCl2, which is beneficial to the subsequent Mg removal process.

[0025] The feeding rate of metal chlorides should be controlled at 2-10 kg / h. This is to avoid a violent thermal reduction reaction between the metal chlorides and magnesium, which could result in an overly dense sintered metal sponge, affecting subsequent processing, or cause magnesium to splatter and encapsulate unreacted chlorides, reducing product purity.

[0026] The alloying element chlorides in this invention can be obtained by purchasing or by selectively recycling solid waste and alloy residue tailings.

[0027] S3 removes unreacted reducing agent magnesium and byproduct magnesium chloride from the sponge titanium-aluminum alloy mixture through vacuum distillation, and then obtains a pure multi-element titanium-aluminum alloy after purging with argon gas and allowing it to cool naturally after exiting the furnace.

[0028] After reduction, the distillation process begins, and the ultimate vacuum of the vacuum system should reach 1×10⁻⁶. -2 Pa, controlling the vacuum level to reach 1×10 -2 Pa to 5×10 -2 After distillation, the temperature inside the reactor rises to 900-1000℃. A slag-hanging bucket and a condenser are assembled on the reduction reactor. The residual Mg and byproduct MgCl2 from the reduction reaction are collected in the slag-hanging bucket after vacuum distillation. After all the residual Mg and byproduct MgCl2 in the furnace are distilled away, the power to the reduction heating furnace is turned off, the vacuum system is shut off, and argon gas is introduced into the vessel to ensure that no gas enters the vessel. The material is then directly discharged from the furnace. After natural cooling, it can be disassembled. During the cooling process, it is essential to maintain positive pressure inside the furnace to prevent low-temperature gas from entering. The material removed from the reduction reactor is the pure multi-element titanium-aluminum alloy product.

[0029] Example 1: Preparation of Ti-48Al-2Cr-2Nb alloy.

[0030] S1 places 6.1 kg of magnesium (Mg is 1.2 times the theoretical total mass of Mg required for the reaction of various metal chlorides into pure metals) and 4.8 kg of aluminum ingots into the reduction reactor, evacuates and heats to degas, and after degassing is completed, the vacuum pump is turned off, argon gas is introduced, and the mixture is heated to turn magnesium and aluminum into liquid.

[0031] After confirming that magnesium and aluminum have melted, S2 begins feeding. At this point, the reactor pressure is stabilized, and the Mg and Al melts are uniformly mixed under low-frequency electromagnetic stirring. Then, 19.1 kg of TiCl4, 0.6 kg of CrCl3, and 0.58 kg of NbCl5 are mixed in the specified proportions and added to the reactor. This mixture undergoes a thermal reduction reaction with the molten magnesium and aluminum to produce a uniform Ti-48Al-2Cr-2Nb alloy, along with the byproduct MgCl2 and residual Mg. Feeding is stopped when the reactor experiences frequent pressure increases and white fumes are observed during venting, marking the end of the reduction process.

[0032] After S3 reduction is complete, the distillation process begins. The ultimate vacuum of the vacuum system should reach 1×10⁻⁶. -2 Pa, after distillation, the temperature in the reduction heating furnace rises to over 900℃. During the distillation stage, the Mg and MgCl2 residues from the reduction reaction are collected in the slag bucket after vacuum distillation. After distillation, a uniform Ti-48Al-2Cr-2Nb alloy can be obtained in the reduction reactor.

[0033] After all Mg and MgCl2 in the furnace have been distilled off, the vacuum generally needs to reach 1×10⁻⁶. -2 Pa to 5×10 -2 To remove the material from the reduction furnace, shut off the power and vacuum system, and fill the vessel with argon gas to ensure no gas enters the vessel. The material can then be removed directly from the furnace. After natural cooling, the material can be disassembled. During the cooling process, it is crucial to maintain positive pressure inside the furnace to prevent low-temperature gas from entering. Disassembling and removing the material from the reduction reactor yields a pure Ti-48Al-2Cr-2Nb alloy product weighing approximately 10 kg.

[0034] Example 2: Preparation of Ti-48Al-2Cr-3Nb alloy.

[0035] The amount of TiCl4 and NbCl4 added was changed to 18.7 kg and 0.8 kg respectively, and other conditions, parameters and steps were the same as in Example 1.

[0036] Example 3: Preparation of Ti-46Al-8Nb alloy.

[0037] The added CrCl3 was removed, and the amounts of TiCl4, Al and NbCl5 were changed to 18.3 kg, 4.6 kg and 2.3 kg, respectively. Other conditions, parameters and steps were the same as in Example 1.

[0038] Example 4: Preparation of Ti-23Al alloy.

[0039] Remove the added CrCl3 and NbCl5, and change the amount of TiCl4, Al and Mg to 29 kg, 2.3 kg and 8.8 kg respectively. Other conditions, parameters and steps are the same as in Example 1.

[0040] Samples of the Ti-Al alloys prepared in Examples 1-4 were taken and analyzed, and the results are listed in Table 1. For ease of comparison, the test results of the above alloys were normalized.

[0041] Table 1. Sampling and testing data of Ti-Al alloy

[0042] As shown in Table 1, the actual detected contents of the main constituent elements (Ti and Al) in the multi-component titanium-aluminum alloy prepared by the method of this invention are highly consistent with the target ratio, and the atomic ratio of titanium to aluminum precisely meets the target ratio, indicating that the preparation method has excellent composition control precision. Specifically, by controlling the feeding rate of metal chloride and the excessive addition of Mg, this invention effectively suppresses the volatilization loss of aluminum during the smelting process under stable pressure and low-frequency electromagnetic stirring, while ensuring the uniform distribution of alloying elements and avoiding compositional segregation.

[0043] This invention prepares Ti-Al alloys by melting and mixing elemental Mg and Al, followed by a thermal reduction reaction with chlorides such as TiCl4, using a magnesium-aluminum metal thermal reduction method. Impurities are then removed by vacuum distillation to obtain a pure Ti-Al alloy. This effectively solves the complex steps of secondary melting in Ti-Al alloys, the difficulties in adding other metal elements, the negative impacts of uneven element content and composition, and reduces the difficulty of batching and mixing Ti-Al alloy materials. It ensures the uniformity of composition and stable quality of Ti-Al alloy ingots, and solves a series of technical problems in the one-step preparation of Ti-Al alloys in China. This invention has practical guiding significance for promoting the upgrading of the titanium industry and enhancing the competitiveness of Chinese titanium enterprises.

[0044] The quaternary titanium-aluminum alloy Ti-48Al-2Cr-2Nb prepared in Example 1 was further analyzed, and the multi-component titanium-aluminum alloys prepared in other examples showed similar results. The ICP quantitative analysis results of possible elements at nine locations in the alloy ingot are shown in Table 2. Table 2 shows that, in addition to the main elements Ti, Al, Cr, and Nb, trace amounts of Fe, O, N, Mg, and Cl are present, with small variations. The main elements Ti, Al, Cr, and Nb exhibit certain macroscopic segregation at different locations, which is far superior to the centimeter-level compositional segregation of traditional ingots.

[0045] Table 2 shows the quantitative analysis results of possible elements in the alloy agglomerate samples from 9 locations, in wt%.

[0046] As shown in Table 2, the compositional fluctuations of the multi-component titanium-aluminum alloy prepared by this invention are minimal at different locations, which fully verifies the stability and reliability of the method of this invention and lays a solid compositional foundation for obtaining titanium-aluminum alloy materials with excellent mechanical properties and high-temperature oxidation resistance.

[0047] To observe its microstructure uniformity, the Ti-48Al-2Cr-2Nb alloy was subjected to SEM+EDS analysis. Other multi-component titanium-aluminum alloys prepared in other examples showed similar results. Figure 3 As shown, Figure 3 The display has a blackish-gray, sponge-like appearance; in terms of element distribution, such as Figure 4As shown, the reduced alloy exhibits a nearly uniform distribution of Ti, Al, Cr, and Nb elements at the 10 μm scale, with no significant segregation. This uniform composition at the microscopic level contributes to a substantial improvement in material properties. This indicates that the multi-component titanium-aluminum alloy prepared using the method of this invention is suitable for single and mixed chloride metal mixtures, facilitating the preparation of titanium-aluminum alloys with varying performance requirements.

[0048] It is worth noting that this process is based on an improvement of the Kroll process for producing sponge titanium and selective chlorination for the recovery of solid waste and alloy residue tailings. Therefore, this process shows great potential in short-process large-scale industrial production, low-cost manufacturing, and the recycling and reuse of solid waste. It is expected to significantly promote the upgrading of the titanium industry and the large-scale civilian application of titanium alloys, and provide new ideas for the preparation of large-size high-entropy alloys.

[0049] The above-described embodiments are merely illustrative of several implementation methods of the present invention, facilitating a detailed and specific understanding of the technical solutions of the present invention. However, they should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided by the present invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this invention patent should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A one-step method for preparing titanium-aluminum alloys using magnesium-aluminum reduction tetrachloride, characterized in that, The steps are as follows: S1 prepares magnesium and aluminum into a molten magnesium-aluminum liquid under an argon atmosphere; wherein the amount of magnesium added is at least 1.2 times the theoretical amount required for titanium tetrachloride and alloying element chlorides to be reduced to pure metal by magnesium; S2, under stable pressure and low-frequency electromagnetic stirring, by controlling the reaction temperature at 600-700℃ and the feeding rate at 2-10kg / h, adds metal chlorides to molten magnesium and aluminum, and prepares a sponge titanium-aluminum alloy mixture through a thermal reduction reaction until the feeding is completed; the metal chlorides include titanium tetrachloride and at least one alloying element chloride MCly, wherein M: Nb, Cr, Mo, W, Si, y: 1, 2, 3, 4; S3 removes unreacted reducing agent magnesium and byproduct magnesium chloride from the sponge titanium-aluminum alloy mixture through vacuum distillation, and then obtains a pure multi-element titanium-aluminum alloy after purging with argon gas and allowing it to cool naturally after exiting the furnace.

2. The method for preparing titanium-aluminum alloy by one-step reduction of magnesium-aluminum tetrachloride according to claim 1, characterized in that, In step S1, the amount of aluminum added is based on the required mass percentage of aluminum in the product multi-component titanium-aluminum alloy, and should meet the requirement that aluminum accounts for 2-63% of the total mass percentage in the product multi-component titanium-aluminum alloy.

3. The method for preparing titanium-aluminum alloy by one-step reduction of magnesium-aluminum tetrachloride according to claim 1, characterized in that, In step S2, the amount of titanium tetrachloride and alloy element chloride added is calculated as the mass percentage of each element required in the product multi-element titanium-aluminum alloy, converted into the mass of the corresponding element chloride.

4. The method for preparing titanium-aluminum alloy by one-step reduction of magnesium-aluminum tetrachloride according to claim 1, characterized in that, In step S2, the pressure is stabilized at 5-25 kPa; the operating frequency of the low-frequency electromagnetic stirrer is 0.5-20 Hz, and the output current is 300-415 A.

5. The method for preparing titanium-aluminum alloy by one-step reduction of magnesium-aluminum tetrachloride according to claim 1, characterized in that, The vacuum distillation conditions in step S3 are as follows: control the vacuum level to reach 1×10⁻⁶. -2 Pa to 5×10 -2 Pa, after distillation, the temperature inside the reactor rises to 900-1000℃.

6. The method for preparing titanium-aluminum alloy by one-step reduction of magnesium-aluminum tetrachloride according to claim 1, characterized in that, In step S3, the furnace is kept under positive pressure during the natural cooling process after the furnace is removed from the furnace.

7. A titanium-aluminum alloy, characterized in that, The titanium-aluminum alloy was prepared according to the one-step method for preparing titanium-aluminum alloy by magnesium-aluminum reduction tetrachloride as described in any one of claims 1 to 6.

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