Low-cost titanium alloy with composite short-range ordered structure and preparation method of low-cost titanium alloy

Abstract

The invention discloses a low-cost titanium alloy with a composite short-range ordered structure, which consists of Ti-Al-Fe-X, and comprises the following components in percentage by mass: 4 to 6 percent of Al, 0 to 3 percent of Fe, 0.3 to 0.5 percent of O, 0.1 to 0.2 percent of C, 0.04 to 0.1 percent of B and 0.3 to 0.6 percent of X, the preparation method of the titanium alloy comprises the following steps: 1, pressing an electrode block; 2, welding the electrode blocks, and smelting to obtain a cast ingot; 3, heating and forging the cast ingot to obtain a forging stock; 4, heating and rolling the forging stock, and annealing to obtain a titanium alloy blank; and 5, electro-thermal treatment. A low-alloy-content component design thought is adopted, a short-distance ordered structure is rapidly formed by controlling titanium alloy components and combining electric heating treatment, the cost is reduced, the preparation efficiency is improved, the high-strength-plasticity and high-hardness low-cost titanium alloy is obtained, and the titanium alloy is suitable for the fields of automobiles, chemical engineering, sports goods and the like.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy material manufacturing, and in particular to a low-cost titanium alloy with a composite short-range ordered structure and a preparation method thereof. Background Art

[0002] Titanium alloys have the characteristics of high specific strength, good corrosion resistance, and excellent high and low temperature performance. They are widely used in aerospace, weapons and equipment, and marine fields. However, titanium alloys still have the problem of high cost. Their cost is nearly 17 times that of steel and 4.5 times that of aluminum alloys, which seriously restricts their application expansion. The cost of titanium alloys mainly depends on the cost of sponge titanium raw materials and the cost of smelting, heat treatment and processing. Therefore, reducing raw material costs and developing short-process and efficient preparation new technologies are the main technical approaches to develop low-cost titanium alloys.

[0003] To this end, the Chinese invention patent with authorization announcement number CN103131896B discloses a low-cost near-β titanium alloy, the mass percentage of alloy elements is: Al 0~3%, Cr 4.1~5.5%, Fe 2~3%, B 0~0.30%, the balance is Ti, the raw material cost is about three-quarters of Ti-6Al-4V, and the basic mechanical properties are equivalent to Ti-6Al-4V. The Chinese invention patent with authorization announcement number CN105525142B discloses a low-cost titanium alloy and a homogenization preparation method thereof, the alloy composition is calculated by mass percentage: Al 1.8~4.0%, V 1.2~2.0%, Fe 1.0~3.0%, O 0.1~0.2%, the rest is Ti and unavoidable impurities, the alloy composition is close to half of the Ti-6Al-4V alloy composition, and the tensile strength is above 796MPa. The Chinese invention patent with the authorization announcement number CN112813303B discloses a low-cost titanium alloy material with a strength level of 1000MPa and a preparation method thereof. The alloy composition is as follows by mass percentage: Al 5.0%~7.0%; Fe 2.0%~5.0%; Cr 1.0%~3.0%; O 0.06%~0.30%; Si 0.01%~0.35%; the balance is Ti and unavoidable impurities, which can reduce the alloy manufacturing cost by 10% to 30%, and the tensile strength is 1000MPa~1200MPa, and the elongation is 8%~20%. The above-mentioned low-cost titanium alloys all use relatively cheap Cr, Fe or Cr-Fe intermediate alloys to completely or partially replace the high-cost V and Mo elements as alloy strengtheners, and at the same time, the content of interstitial elements such as O, B, and Si is increased to form interstitial solid solutions in the titanium alloy lattice to improve the strength of the titanium alloy. However, such low-cost titanium alloy materials still contain a certain amount of high-cost V, which only partially reduces the cost of alloy raw materials. In addition, such low-cost titanium alloys contain high content of Cr and Fe alloying elements, which will generally cause smelting component segregation, thereby increasing the smelting and heat treatment costs of the alloy, and failing to achieve low-cost full-process preparation. Therefore, the design and preparation of low-alloy full-process low-cost titanium alloys is a new idea for the development of new low-cost titanium alloy materials.

[0004] Interstitial elements can inhibit twinning and hinder dislocation slip through direct solute-dislocation interaction. A small amount of interstitial elements entering titanium can achieve high strengthening ability. Improving the strength of titanium alloys through solid solution strengthening of interstitial elements is an effective way to develop low-cost high-strength titanium alloys. However, solid solution strengthening of interstitial elements has a disadvantage, which can lead to a sharp loss of plasticity. Therefore, it is difficult to meet the performance requirements of titanium alloys by adding interstitial elements alone. When a certain amount of Ti is added to replace Al, a short-range ordered domain DO with a certain space group structure will be formed. 19At the same time, interstitial elements are added to the alloy. The interstitial elements will preferentially occupy the interstitial positions of the short-range structure to form a composite short-range ordered structure. The formation of the composite short-range ordered structure will pin dislocations, inducing the slip movement of dislocations during plastic deformation, thereby improving the plasticity of the material. Although adding a certain amount of Al and interstitial elements to Ti does produce a deformation mode that is conducive to obtaining good plasticity, the content of the beneficial combination of the two types of alloy additives has not been reported in the prior art. In addition, the conditions for the formation of short-range ordered structures in titanium alloys are very harsh, and the existing methods require aging treatment for hundreds of hours, which greatly increases the preparation cost of titanium alloy materials, which obviously does not meet the requirements of low-cost full-process low-cost preparation of low-cost titanium alloys.

[0005] Therefore, there is an urgent need in the prior art for a full-process low-cost preparation method for the design of low-alloying components and short-range ordered structures of low-cost titanium alloys. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a low-cost titanium alloy with a composite short-range ordered structure and a preparation method thereof in view of the deficiencies of the above-mentioned prior art. The method adopts a low-alloy content composition design idea. On the basis of adopting the short-range ordered domain element Al, the interstitial elements O, B, C and Fe with a small mass percentage are added as the main strengthening elements to improve the strength and hardness of the titanium alloy, and at the same time, a Ti-Al-X composite short-range ordered structure is formed to improve the plasticity of the titanium alloy, reduce the alloy cost, and realize the design and preparation of a low-cost high-strength titanium alloy, solving the problem of low-cost preparation of the existing short-range ordered structure titanium alloy throughout the process.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a low-cost titanium alloy with a composite short-range ordered structure, characterized in that the composition of the titanium alloy is Ti-Al-Fe-X, wherein the mass percentage of the short-range ordered domain element Al is 4%~6%, the mass percentage of the strengthening element Fe is 0%~3%, and the composite short-range ordered additional element X is selected from one or two of the interstitial elements O, B, and C, and the mass percentages are respectively O 0.3%~0.5%, C 0.1%~0.2%, B 0.04%~0.1%, and the total content of X is 0.3%~0.6%, and the balance is Ti and unavoidable impurities; the tensile strength R of the titanium alloy at 25°C m ≥1080MPa, elongation after fracture A≥12%, Rockwell hardness≥40HRC.

[0008] The above-mentioned low-cost titanium alloy with a composite short-range ordered structure is characterized in that the composition of the titanium alloy is Ti-Al-Fe-X, wherein the mass percentage of the short-range ordered domain element Al is 4%~5%, the mass percentage of the strengthening element Fe is 1.5%~2%, and the composite short-range ordered additional element X is selected from one or two of the interstitial elements O, B, and C, and the mass percentages are respectively O 0.3%~0.4%, C 0.1%~0.15%, and B 0.04%~0.06%, and the total content of X is 0.3%~0.55%, and the balance is Ti and unavoidable impurities.

[0009] The above-mentioned low-cost titanium alloy with a composite short-range ordered structure is characterized in that the composition of the titanium alloy is Ti-Al-Fe-X, wherein the mass percentage of the short-range ordered domain element Al is 4%, the mass percentage of the strengthening element Fe is 1.7%, and the composite short-range ordered added element X is the interstitial element O and B, with the mass percentages of O 0.4%, B 0.06%, and the remainder is Ti and unavoidable impurities.

[0010] At the same time, the present invention also discloses a method for preparing the above-mentioned low-cost titanium alloy with a composite short-range ordered structure, characterized in that the method comprises the following steps: Step 1: According to the designed composition of the target product, the raw materials are mixed and pressed to obtain an electrode block; Step 2: welding the electrode blocks obtained in step 1 into long strip electrodes, and then performing vacuum consumable smelting twice to obtain an ingot; Step 3, heating the ingot obtained in step 3 to 1000° C. to 1100° C. for secondary forging, and then water quenching to obtain a forging blank; Step 4: heating the forged billet obtained in step 3 to 800° C. to 850° C. for rolling, wherein the total rolling deformation is not less than 60%, and then annealing is performed at 800° C. for 0.5 to 1 h to obtain a titanium alloy billet; Step 5: subjecting the titanium alloy blank obtained in step 4 to electrothermal treatment to obtain a low-cost titanium alloy having a composite short-range ordered structure.

[0011] The above method is characterized in that the raw materials in step 1 are derived from aluminum beans, aluminum tubes, iron nails, grade 3 titanium sponge, TiO 2 Powder, TiB 2 Powder, carbon powder, industrial titanium recycling material, sponge titanium recycling material; the mass content of industrial titanium recycling material and sponge titanium recycling material in the raw materials is 50% to 70%. The present invention reduces the cost of titanium alloy preparation by using a large amount of low-priced recycled materials as raw materials.

[0012] The above method is characterized in that, in the process of preparing the ingredients and pressing the electrode in step 1, TiO2 Powder, TiB 2 After the powder and carbon powder are evenly mixed, they are poured into the aluminum tube and sealed. When pressing the electrode, the aluminum tube filled with powder is evenly arranged at the top, middle and bottom of the electrode. Through this distribution method, the powder raw materials are evenly distributed in the electrode, ensuring uniform subsequent smelting.

[0013] The above method is characterized in that the parameters of the electrothermal treatment in step 5 are: temperature 400°C-450°C, treatment time 1h-5h. The temperature of the electrothermal treatment ensures the generation of a short-range ordered phase in the titanium alloy, and the treatment time is shorter than that of conventional heat treatment.

[0014] Compared with the prior art, the present invention has the following advantages: 1. The titanium alloy of the present invention adopts a low alloy content composition design concept. On the basis of adopting the short-range ordered domain element Al, the strength and hardness of the titanium alloy are improved by adding interstitial elements O, B, and C with a small mass percentage as the main strengthening elements. At the same time, a Ti-Al-X composite short-range ordered structure is formed to improve the plasticity of the titanium alloy, avoiding a sharp drop in plasticity due to excessive interstitial elements, and using Fe as a secondary strengthening element to further improve the strength and hardness of the titanium alloy, optimize the titanium alloy structure, improve the plasticity of the titanium alloy, and effectively reduce the mass proportion of the alloying elements, so that the alloy raw material cost is only half of that of the Ti-6Al-4V alloy.

[0015] 2. Based on the theory of short-range ordered structure strengthening and toughening, the present invention controls the composition of titanium alloy and combines the electrothermal treatment preparation process to construct interstitial element-assisted Ti-Al-O, Ti-Al-B and Ti-Al-C composite short-range ordered structures, realizes the design and preparation of low-cost high-strength titanium alloy, improves the strength, hardness and plasticity of titanium alloy, and finally improves the tensile strength R of titanium alloy at 25°C. m ≥1080MPa, elongation after fracture A≥12%, Rockwell hardness≥40HRC, achieving strength-plasticity matching, and the mechanical properties are much higher than those of Ti-6Al-4V alloy.

[0016] 3. The present invention adopts an electrothermal treatment process and combines thermal effect and non-thermal effect to prepare short-range ordered structure, which shortens the formation time of short-range ordered structure of titanium alloy from hundreds of hours in the prior art to less than a few hours, thereby realizing the rapid and efficient preparation of short-range ordered structure of titanium alloy.

[0017] 4. By adding O, B, C and Fe in small mass percentages as strengthening agents to the titanium alloy of the present invention, the smelting component segregation caused by excessive content of alloying elements such as Fe is reduced, and the alloy smelting and heat treatment costs are further reduced.

[0018] 5. The present invention realizes the low-cost preparation of titanium alloy in the whole process by adding cheap elements, reducing the content of alloying elements and rapid electric heat treatment process. The process steps are simple, the cost is reduced by more than 20%, and the production efficiency is increased by more than 30%. It is suitable for large-scale production and has broad application prospects in the automotive, chemical and sporting goods industries.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a tensile curve diagram of the low-cost titanium alloy with a composite short-range ordered structure prepared in Examples 1 to 5 of the present invention.

[0021] Figure 2 It is a tensile curve diagram of the low-cost titanium alloy with a composite short-range ordered structure prepared in Example 1 of the present invention and the titanium alloy prepared in Comparative Examples 1-2. DETAILED DESCRIPTION

[0022] Example 1 The composition of the low-cost titanium alloy with a composite short-range ordered structure in this embodiment is Ti-Al-Fe-O, wherein the mass percentage of the short-range ordered domain element Al is 5%, the mass percentage of the strengthening element Fe is 1.5%, the mass percentage of the composite short-range ordered added element O is 0.35%, and the remainder is Ti and unavoidable impurities.

[0023] The method for preparing a low-cost titanium alloy having a composite short-range ordered structure in this embodiment comprises the following steps: Step 1: According to the designed composition of the target product Ti-5Al-1.5Fe-0.35O, select aluminum beans, aluminum tubes, iron nails, TiO 2 Powder, sponge titanium, grade 3 sponge titanium, industrial titanium recycled material, and sponge titanium recycled material are used as raw materials for batching, and the mass content of industrial titanium recycled material and sponge titanium recycled material in the raw materials is 50%. 2 The powder is poured into the aluminum tube and sealed, and when pressing the electrode, the aluminum tube filled with the powder is evenly arranged at the upper, middle and lower positions of the electrode, and then pressed to obtain an electrode block; Step 2: welding the electrode blocks obtained in step 1 into long strip electrodes, and then performing vacuum consumable smelting twice to obtain an ingot; Step 3, heating the ingot obtained in step 3 to 1000° C. for secondary forging, and then water quenching to obtain a forging blank; Step 4: heating the forging blank obtained in step 3 to 800° C. for rolling, with a total rolling deformation of 90%, and then annealing at 800° C. for 1 h to obtain a titanium alloy bar; Step 5: subjecting the titanium alloy rod obtained in step 4 to an electric heat treatment at a temperature of 450° C. for a treatment time of 1 h to obtain a low-cost titanium alloy with a composite short-range ordered structure.

[0024] Example 2 The composition of the low-cost titanium alloy with a composite short-range ordered structure in this embodiment is Ti-Al-OB, wherein the mass percentage of the short-range ordered domain element Al is 6%, the mass percentage of the composite short-range ordered additional element O is 0.3%, the mass percentage of B is 0.04%, and the remainder is Ti and unavoidable impurities.

[0025] The method for preparing a low-cost titanium alloy having a composite short-range ordered structure in this embodiment comprises the following steps: Step 1: According to the designed composition of the target product Ti-6Al-0.3O-0.04B, select aluminum beans, aluminum tubes, TiO 2 Powder, TiB 2 Powder, sponge titanium, grade 3 sponge titanium, industrial titanium recycled material, and sponge titanium recycled material are used as raw materials for batching, and the mass content of industrial titanium recycled material and sponge titanium recycled material in the raw materials is 60%. 2 Powder, TiB 2 The powder is poured into the aluminum tube and sealed, and when pressing the electrode, the aluminum tube filled with the powder is evenly arranged at the upper, middle and lower positions of the electrode, and then pressed to obtain an electrode block; Step 2: welding the electrode blocks obtained in step 1 into long strip electrodes, and then performing vacuum consumable smelting twice to obtain an ingot; Step 3, heating the ingot obtained in step 3 to 1050° C. for secondary forging, and then water quenching to obtain a forging blank; Step 4: heating the forged billet obtained in step 3 to 800° C. for rolling, with a total rolling deformation of 80%, and then annealing at 800° C. for 1 h to obtain a titanium alloy plate; Step 5: subjecting the titanium alloy plate obtained in step 4 to an electric heat treatment at a temperature of 420° C. for a treatment time of 2 h to obtain a low-cost titanium alloy with a composite short-range ordered structure.

[0026] Example 3 The composition of the low-cost titanium alloy with a composite short-range ordered structure in this embodiment is Ti-Al-CB, wherein the mass percentage of the short-range ordered domain element Al is 5%, the mass percentage of the composite short-range ordered additional element C is 0.2%, the mass percentage of B is 0.1%, and the remainder is Ti and unavoidable impurities.

[0027] The method for preparing a low-cost titanium alloy having a composite short-range ordered structure in this embodiment comprises the following steps: Step 1: According to the designed composition of the target product Ti-5Al-0.2C-0.1B, select aluminum beans, aluminum tubes, TiO 2 Powder, carbon powder, sponge titanium, grade 3 sponge titanium, industrial titanium recycled materials, and sponge titanium recycled materials are used as raw materials for batching, and the mass content of industrial titanium recycled materials and sponge titanium recycled materials in the raw materials is 70%. 2 The powder is poured into the aluminum tube and sealed, and when pressing the electrode, the aluminum tube filled with the powder is evenly arranged at the upper, middle and lower positions of the electrode, and then pressed to obtain an electrode block; Step 2: welding the electrode blocks obtained in step 1 into long strip electrodes, and then performing vacuum consumable smelting twice to obtain an ingot; Step 3, heating the ingot obtained in step 3 to 1100° C. for secondary forging, and then water quenching to obtain a forging blank; Step 4: heating the forged billet obtained in step 3 to 850° C. for rolling, with a total rolling deformation of 60%, and then annealing at 800° C. for 0.5 h to obtain a titanium alloy plate; Step 5: subjecting the titanium alloy plate obtained in step 4 to an electric heat treatment at a temperature of 405° C. for a treatment time of 5 h to obtain a low-cost titanium alloy with a composite short-range ordered structure.

[0028] Example 4 The composition of the low-cost titanium alloy with a composite short-range ordered structure in this embodiment is Ti-Al-Fe-OB, wherein the mass percentage of the short-range ordered domain element Al is 4%, the mass percentage of the strengthening element Fe is 1.7%, the mass percentage of the composite short-range ordered additional element O is 0.4%, the mass percentage of B is 0.06%, and the remainder is Ti and unavoidable impurities.

[0029] The method for preparing a low-cost titanium alloy having a composite short-range ordered structure in this embodiment comprises the following steps: Step 1: According to the designed composition of the target product Ti-4Al-1.7Fe-0.4O-0.06B, select aluminum beans, aluminum tubes, iron nails, TiO 2 Powder, TiB 2 Powder, sponge titanium, grade 3 sponge titanium, industrial titanium recycled material, and sponge titanium recycled material are used as raw materials for batching, and the mass content of industrial titanium recycled material and sponge titanium recycled material in the raw materials is 65%. 2 Powder and TiB 2 The powder is poured into the aluminum tube and sealed, and when pressing the electrode, the aluminum tube filled with the powder is evenly arranged at the upper, middle and lower positions of the electrode, and then pressed to obtain an electrode block; Step 2: welding the electrode blocks obtained in step 1 into long strip electrodes, and then performing vacuum consumable smelting twice to obtain an ingot; Step 3, heating the ingot obtained in step 3 to 1100° C. for secondary forging, and then water quenching to obtain a forging blank; Step 4: heating the forging blank obtained in step 3 to 850° C. for rolling, with a total rolling deformation of 80%, and then annealing at 800° C. for 1 h to obtain a titanium alloy bar; Step 5: subject the titanium alloy rod obtained in step 4 to an electric heat treatment at a temperature of 425° C. for a treatment time of 3 h to obtain a low-cost titanium alloy with a composite short-range ordered structure.

[0030] Example 5 The composition of the low-cost titanium alloy with a composite short-range ordered structure in this embodiment is Ti-Al-Fe-OC, wherein the mass percentage of the short-range ordered domain element Al is 4.5%, the mass percentage of the strengthening element Fe is 3%, the mass percentage of the composite short-range ordered additional element O is 0.5%, the mass percentage of C is 0.1%, and the remainder is Ti and unavoidable impurities.

[0031] The method for preparing a low-cost titanium alloy having a composite short-range ordered structure in this embodiment comprises the following steps: Step 1: According to the designed composition of the target product Ti-4.5Al-3Fe-0.5O-0.1C, select aluminum beans, aluminum tubes, iron nails, TiO 2 Powder, carbon powder, sponge titanium, grade 3 sponge titanium, industrial titanium recycled materials, and sponge titanium recycled materials are used as raw materials for batching, and the mass content of industrial titanium recycled materials and sponge titanium recycled materials in the raw materials is 55%. 2 Powder and carbon powder are poured into an aluminum tube and sealed, and when pressing the electrode, the aluminum tube filled with powder is evenly arranged at the upper, middle and lower positions of the electrode, and then pressed to obtain an electrode block; Step 2: welding the electrode blocks obtained in step 1 into long strip electrodes, and then performing vacuum consumable smelting twice to obtain an ingot; Step 3, heating the ingot obtained in step 3 to 1050° C. for secondary forging, and then water quenching to obtain a forging blank; Step 4: heating the forging blank obtained in step 3 to 850° C. for rolling, with a total rolling deformation of 65%, and then annealing at 800° C. for 0.5 h to obtain a titanium alloy bar; Step 5: subjecting the titanium alloy rod obtained in step 4 to an electric heat treatment at a temperature of 445° C. for a treatment time of 2.5 h to obtain a low-cost titanium alloy with a composite short-range ordered structure.

[0032] Comparative Example 1 The composition of the titanium alloy in this comparative example is the same as that in Example 1, but no electric heat treatment is performed during the preparation process, that is, the prepared titanium alloy does not have a composite short-range ordered structure.

[0033] Comparative Example 2 The Ti-6Al-4V titanium alloy of this comparative example is composed of the following elements in percentage by mass: Al 6%, V 4%, and the balance being Ti and inevitable impurity elements.

[0034] The preparation method of the Ti-6Al-4V titanium alloy of this comparative example comprises the following steps: Step 1: According to the designed composition Ti-6Al-4V of the target product, aluminum beans, Al-85V and titanium sponge are selected as raw materials for mixing, and then pressed to obtain an electrode block; Step 2: subjecting the electrode block obtained in step 1 to vacuum consumable smelting twice to obtain an ingot; Step 3, heating the ingot obtained in step 3 to 1050° C. and performing three forgings, and then water quenching to obtain a forging blank; Step 4: heating the forging blank obtained in step 3 to 850°C for rolling, with a total rolling deformation of 75%, and then annealing at 800°C for 0.5h to obtain Ti-6Al-4V titanium alloy.

[0035] The performance tests were performed on the low-cost titanium alloys with a composite short-range ordered structure prepared in Examples 1 to 5 of the present invention, the titanium alloy without a composite short-range ordered structure prepared in Comparative Example 1, and the Ti-6Al-4V titanium alloy prepared in Comparative Example 2: (1) The tensile properties were tested according to the test method specified in GB / T 228.1-2021; (2) The Rockwell hardness was tested according to the test method specified in GB / T 230.1-2018. The results are shown in Tables 1 and 2. Figure 1~Figure 2 shown.

[0036]

[0037] Combining Table 1 and Figure 1~Figure 2 It can be seen that compared with the titanium alloy without a composite short-range ordered structure prepared in Comparative Example 1, the low-cost titanium alloy with a composite short-range ordered structure prepared in Example 1 of the present invention has significantly increased strength and hardness while keeping the elongation basically unchanged, and each performance is better than the Ti-6Al-4V titanium alloy prepared in Comparative Example 2. At the same time, the yield strength R of the low-cost titanium alloy with a composite short-range ordered structure prepared in Examples 1 to 5 of the present invention is p0.2 ≥1000MPa, tensile strength R m ≥1080MPa, elongation after fracture A≥12%, Rockwell hardness≥40HRC.

[0038] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A low-cost titanium alloy with a composite short-range ordered structure, characterized in that: The composition of the titanium alloy is Ti-Al-Fe-X, wherein the mass percentage of the short-range ordered domain element Al is 4% to 6%, the mass percentage of the strengthening element Fe is 0% to 3%, the composite short-range ordered added element X is selected from one or two of the interstitial elements O, B and C, and the mass percentages are respectively O 0.3% to 0.5%, C 0.1% to 0.2%, B 0.04% to 0.1%, and the total content of X is 0.3% to 0.6%, and the balance is Ti and unavoidable impurities; the tensile strength R m ≥1080MPa, elongation after fracture A≥12%, Rockwell hardness≥40HRC.

2. A low-cost titanium alloy with a composite short-range ordered structure according to claim 1, characterized in that: The titanium alloy has a composition of Ti-Al-Fe-X, wherein the mass percentage of the short-range ordered domain element Al is 4%-5%, the mass percentage of the strengthening element Fe is 1.5%-2%, the composite short-range ordered added element X is selected from one or two of the interstitial elements O, B and C, and the mass percentages are respectively O 0.3%-0.4%, C 0.1%-0.15%, B 0.04%-0.06%, and the total content of X is 0.3%-0.55%, and the balance is Ti and unavoidable impurities.

3. The low-cost titanium alloy with a composite short-range ordered structure according to claim 1, characterized in that: The composition of the titanium alloy is Ti-Al-Fe-X, wherein the mass percentage of the short-range ordered domain element Al is 4%, the mass percentage of the strengthening element Fe is 1.7%, and the composite short-range ordered added element X is the interstitial element O and B, with the mass percentages of O0.4% and B 0.06% respectively, and the balance is Ti and unavoidable impurities.

4. A method for preparing a low-cost titanium alloy having a composite short-range ordered structure as claimed in any one of claims 1 to 3, characterized in that: The method comprises the following steps: Step 1: According to the designed composition of the target product, the raw materials are mixed and pressed to obtain an electrode block; Step 2: welding the electrode blocks obtained in step 1 into long strip electrodes, and then performing vacuum consumable smelting twice to obtain an ingot; Step 3, heating the ingot obtained in step 3 to 1000° C. to 1100° C. for secondary forging, and then water quenching to obtain a forging blank; Step 4: heating the forged billet obtained in step 3 to 800° C. to 850° C. for rolling, wherein the total rolling deformation is not less than 60%, and then annealing is performed at 800° C. for 0.5 to 1 h to obtain a titanium alloy billet; Step 5: subjecting the titanium alloy blank obtained in step 4 to electrothermal treatment to obtain a low-cost titanium alloy having a composite short-range ordered structure.

5. The method according to claim 4, characterized in that The raw materials described in step 1 are derived from aluminum beans, aluminum tubes, iron nails, grade 3 sponge titanium, TiO2 powder, TiB2 powder, carbon powder, industrial titanium recycling materials, and sponge titanium recycling materials; the mass content of industrial titanium recycling materials and sponge titanium recycling materials in the raw materials is 50% to 70%.

6. The method according to claim 5, characterized in that In the process of preparing the ingredients and pressing the electrode in step 1, the TiO2 powder, TiB2 powder and carbon powder are mixed evenly and poured into an aluminum tube and sealed. When pressing the electrode, the aluminum tube filled with the powder is evenly arranged at the upper, middle and lower positions of the electrode.

7. The method according to claim 4, characterized in that The parameters of the electrothermal treatment in step 5 are: temperature 400° C. to 450° C., and treatment time 1 h to 5 h.

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