Low-cost high-performance titanium alloy with fine grain structure and additive manufacturing method thereof

Abstract

The invention belongs to the technical field of laser additive manufacturing, and relates to a low-cost high-performance titanium alloy with a fine grain structure and an additive manufacturing method of the low-cost high-performance titanium alloy with the fine grain structure, titanium alloy powder for additive manufacturing comprises micron pure Ti powder, micro-nano pure Fe powder, micro-nano TiO2 powder and nano Y2O3 powder, and the nano Y2O3 powder is evenly distributed on the surfaces of other powder; the titanium alloy comprises the following chemical components in percentage by mass: 2.7-3.5% of Fe element, 0.3-0.5% of O element and the balance of Ti. On the basis of a traditional selective laser melting process, the periodic remelting procedure is introduced, the microstructure characteristics of the titanium alloy are improved, the grain structure is refined, meanwhile, the double effects of grain refining and intergranular brittleness relieving are achieved by introducing nano Y2O3 particles, and an alloy sample prepared through the method shows excellent matching of strength and plasticity and is suitable for large-scale industrial production. And the tensile strength is larger than or equal to 1100 MPa, the percentage elongation after fracture is larger than or equal to 15%, and the comprehensive mechanical property of the Ti-O-Fe alloy is further improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of laser additive manufacturing, and relates to a low-cost high-performance titanium alloy with a fine-grained structure and an additive manufacturing method thereof. BACKGROUND

[0002] Titanium alloy is a lightweight high-strength material facing high-end high-precision equipment, the world's scientific and technological frontier and the country's major needs, and has comprehensive performance such as high specific strength, high specific modulus and good corrosion resistance. However, with the continuous progress of aerospace technology and equipment manufacturing, the requirements for the performance of titanium alloy are also increasing. Key components such as engine blades and fasteners need to use lightweight and more high-strength titanium alloys to meet the stringent service conditions. High-strength titanium alloys are expected to be used to manufacture missile skins and automobile engine connecting rods, thereby improving energy economy. Therefore, developing new titanium alloy materials with excellent comprehensive mechanical properties has become a new hot research direction. In addition, the raw material cost of titanium alloy is relatively high, which greatly limits its wide application in low-altitude unmanned aerial vehicles, weapon manufacturing, automobile industry and other fields. Aluminum alloy and steel material have a large material share in the civil market due to their cost advantage, but titanium alloy has significant performance advantages in the demand for lightweight, specific strength, corrosion resistance and high temperature resistance. Research and development of new low-cost titanium alloys are beneficial to break through the industrial development of titanium alloys in non-advanced and non-aerospace markets, and to layout the future "low-altitude economy" centered on low-altitude unmanned aerial vehicles and low-altitude operation services.

[0003] Additive manufacturing technology can realize rapid near-net shaping of titanium alloy materials, and has metallurgical characteristics such as fast cooling rate and non-equilibrium solidification, and can realize in-situ alloying material design capability, so that the composition and microstructure of titanium alloy can be controlled with high freedom, which is beneficial to design and prepare high-performance titanium alloy materials. At present, the most widely used is alpha + beta titanium alloy Ti6Al4V, but its cost is still high, and the price of V-Al intermediate alloy in raw materials is expensive, and the preparation process is complex, which is an important reason for the difficulty of Ti6Al4V alloy cost reduction and the difficulty of continuous popularization in the civil market. Developing new low-cost titanium alloys is a key research direction in the future.

[0004] Designing a new Ti-O-Fe alloy is expected to further reduce the raw material cost of titanium alloy while achieving excellent comprehensive mechanical properties. Fe and O elements are both phase stabilizing elements, but also elements that cause brittleness in titanium alloys, so it is necessary to finely control the microelement segregation behavior and alloy grain structure, especially for the laser selective melting technology platform with wider applicability, to develop low-cost, high-performance Ti-O-Fe alloy powder and preparation scheme, and to provide technical support for the application of titanium alloy. SUMMARY

[0005] Therefore, the present application aims to provide a low-cost high-performance titanium alloy with fine-grained structure and an additive manufacturing method thereof, based on the unique solidification and phase transformation mechanism of additive manufacturing, a Ti-O-Fe alloy composition is designed, and a powder modification and process preparation method suitable for selective laser melting is proposed, aiming to obtain a Ti-O-Fe alloy material with fine structure and excellent mechanical properties.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] On the one hand, the present application provides a titanium alloy powder suitable for selective laser melting additive manufacturing, which is mixed by pure Ti powder, pure Fe powder, TiO2 powder and Y2O3 powder;

[0008] Among them, the Y2O3 powder is uniformly attached to the surface of the pure Ti powder, the pure Fe powder and the TiO2 powder, so as to realize the nanoscale dispersion and control the oxygen element distribution, and avoid the grain boundary embrittlement.

[0009] Further, the titanium alloy powder comprises, by mass percentage: 2.7% to 3.5% of pure Fe powder, 0.9% to 1.2% of TiO2 powder, 0.1% to 0.2% of Y2O3 powder, and the balance of pure Ti powder.

[0010] The pure Ti powder is a 15-53μm spherical powder, the pure Fe powder is a 0.5-1μm spherical powder, the TiO2 powder is a 0.5-1μm spherical powder, and the Y2O3 powder is a 10-50nm non-spherical powder.

[0011] On the other hand, the present application also provides a preparation method of titanium alloy powder, comprising the following steps:

[0012] (1) adding pure Ti powder, pure Fe powder, TiO2 powder and Y2O3 powder into a mixing device according to a preset ratio, and carrying out multi-stage vibration mixing to make the Y2O3 powder uniformly adhere to the surface of other powders;

[0013] (2) vacuum drying the mixed powder to remove moisture and stabilize the powder structure.

[0014] Further, the multi-stage vibration mixing in step (1) is specifically: in the high-frequency mixing stage, a frequency of 90Hz, an acceleration of 80g and a time of 6min are adopted to disperse Y2O3 nanoparticles; in the low-frequency mixing stage, a frequency of 60Hz, an acceleration of 80g and a time of 20min are adopted to realize the uniform adhesion of Y2O3 on the surface of other powders.

[0015] Further, the vacuum drying condition in step (2) is a temperature of 80-100℃ and a time of 3-6h.

[0016] In another aspect, the present application also provides a low-cost high-performance titanium alloy with fine-grained structure using the titanium alloy powder, and an additive manufacturing method of the low-cost high-performance titanium alloy, comprising the following steps:

[0017] (1) Establishing a three-dimensional printing model and generating a laser scanning program;

[0018] (2) Laying a powder bed in a low-oxygen environment and laser melting the titanium alloy powder layer by layer;

[0019] (3) After completing the printing, taking out and post-processing the component.

[0020] Further, the low-oxygen environment in the step (2) is that the oxygen content in the forming cabin is less than 100 ppm, high-purity argon gas is used for washing and continuous aeration;

[0021] The laser process parameters are a spot diameter of 40-60 μm, a power of 100-300 W, a scanning speed of 1000-1400 mm / s, a single layer thickness of 20-40 μm, an overlap rate of 40-60%, and a substrate preheating temperature of 150-200℃.

[0022] Further, a periodic remelting process is adopted in the step (2), wherein the periodic remelting process is to perform remelting once after every 2 layers of deposition without powder laying;

[0023] The remelting parameters are a laser power of 100-200 W, a scanning speed of 1000-1200 mm / s, an overlap rate of 0-10%, and a scanning path of a single layer parallel line mode.

[0024] Further, the post-processing in the step (3) includes machining cutting of the component, tissue characterization and mechanical testing.

[0025] In another aspect, the present application also provides a low-cost high-performance titanium alloy with fine-grained structure, which is prepared by the additive manufacturing method, and the chemical composition of the low-cost high-performance titanium alloy is 2.7%-3.5% of Fe element, 0.3%-0.5% of O element, and the balance of Ti.

[0026] The present application has the following advantages:

[0027] 1. In the design of Ti-O-Fe additive manufacturing powder raw materials, a proper amount of Y2O3 powder particles is added for raw material modification. Y2O3 powder provides the O content in the target composition of the alloy, ensuring the volume fraction and stability of the alpha phase in the alloy organization; more importantly, Y element is a strong oxygen element, which preferentially combines with O to form an oxide during alloy solidification, which is beneficial to alleviate the segregation degree of O at the grain boundary, slow down the intergranular brittleness of the Ti-O alloy system, effectively enhance the ductility of the additive alloy component, on the other hand, the melting point of Y2O3 is about 2400℃, the precipitation of nano Y2O3 particles during the L→β phase transition of titanium alloy can act as nucleation points to promote β phase refinement, and then strengthen the nucleation and variant selection of α' / α phase, realizing the high strength and toughness of Ti-O-Fe alloy.

[0028] 2. In the design of Ti-O-Fe additive manufacturing process, a periodic laser remelting process is introduced to realize the fine control of the microstructure of Ti-O-Fe additive alloy. The additive manufacturing process parameters used in the application aim to create rapid solidification conditions to obtain non-equilibrium α' / α microstructure, and the subsequent laser remelting process introduces appropriate heat to promote the transformation of α' organization to α+β phase in a very short time, which can form fine lath structure, and can also appropriately promote the uniformity of O and Fe elements, avoid the brittleness caused by local high concentration O segregation and the "β spot" caused by local Fe segregation. The above control mechanism can realize the strength-plasticity matching improvement of Ti-O-Fe alloy, and finally its tensile strength can reach 850-1200MPa, and the elongation can reach 8-15%.

[0029] 3. The application provides an additive manufacturing solution of high-performance and low-cost titanium alloy, which uses O and Fe elements to promote the stability of α and β phases, forms a dual-phase high-strength titanium alloy structure, and nano Y2O3 non-spherical powder is low in price and easy to obtain, which is beneficial to batch production and preparation.

[0030] Other advantages, objects, and features of the present application will be apparent to those skilled in the art from the following specification, and it is intended to be covered by the following claims. The objects and other advantages of the present application can be achieved and obtained by the following specification. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to make the objects, technical solutions and advantages of the present application clearer, the preferred detailed description of the present application will be described below with reference to the accompanying drawings, in which:

[0032] Figure 1The micro-morphology diagram of the titanium alloy powder in Example 1 is shown in the figure, wherein (a) is a micrograph of the uniformly dispersed mixture of pure Ti powder, pure Fe powder, TiO2 powder and Y2O3 powder; (b) is a micrograph of the adsorption of nano Y2O3 powder on the surface of pure Ti powder;

[0033] Figure 2 The microstructure comparison diagram of the titanium alloy component prepared in Example 1 and Comparative Example 1 is shown in the figure, wherein (a) is a Ti-O-Fe alloy microstructure image prepared without adding Y2O3 powder raw material and without applying a remelting process, and (b) is a Ti-O-Fe alloy microstructure image prepared by adding 0.15wt% Y2O3 powder raw material and applying a remelting process;

[0034] Figure 3 The tensile property comparison diagram of the titanium alloy component prepared in Example 1 and Comparative Example 1 is shown in the figure. DETAILED DESCRIPTION

[0035] The embodiments of the present application will be described in detail below with specific reference to specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. The present application can also be implemented or applied in different specific embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application. It should be noted that the figures provided in the following examples only illustrate the basic concept of the present application in a schematic manner, and the features in the following examples and embodiments can be combined with each other without conflict.

[0036] The figures are only used for illustrative purposes, and the representations are only schematic diagrams, not physical diagrams, and should not be understood as limiting the present application; in order to better illustrate the embodiments of the present application, some components in the figures may be omitted, enlarged or reduced, and do not represent the actual size of the product; it is understandable to those skilled in the art that some well-known structures and their descriptions in the figures may be omitted.

[0037] The same or similar reference numerals in the figures of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back" and the like are based on the orientations or positional relationships shown in the figures, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the figures are only used for illustrative purposes, and should not be understood as limiting the present application, and for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0038] Example 1

[0039] A titanium alloy powder material is prepared, raw materials of which include pure Ti powder, pure Fe powder, TiO2 powder and Y2O3 powder. The mass percentage of each type of raw material powder is as follows: pure Fe powder is 3%, TiO2 powder is 0.92%, Y2O3 powder is 0.15%, and the balance is pure Ti powder.

[0040] The pure Ti powder in the titanium alloy powder is 15-53 μm spherical powder, the pure Fe powder is 0.5-1 μm spherical powder, the TiO2 powder is 0.5-1 μm spherical powder, and the Y2O3 powder is 10-50 nm non-spherical powder.

[0041] The titanium alloy powder material is obtained according to the following steps:

[0042] (1) The pure Ti powder, pure Fe powder, TiO2 powder and Y2O3 powder are mixed and treated, and the nano Y2O3 powder is uniformly attached to the surface of the other micron powders. In order to achieve good powder mixing effect and dispersion effect, a multi-stage powder mixing treatment is carried out by using a sound resonance device, and the steps are as follows:

[0043] High frequency mixing, frequency 90hz, acceleration 80g, mixing time 6min, the purpose is to break the agglomeration of small nano powder, and improve the mixing uniformity of the next step;

[0044] Middle-low frequency mixing, frequency 60hz, acceleration 80g, mixing time 20min, the purpose is to uniformly disperse the raw material powder, and make the Y2O3 particles uniformly adhere to the surface of the Ti powder and Fe powder and TiO2 powder.

[0045] (2) The mixed titanium alloy powder is placed in a vacuum drying oven for drying treatment, the drying oven temperature is 80-100℃, and the drying time is 3-6h. The micrograph of the titanium alloy powder after the powder mixing process is shown in Figure 1 It can be seen that the various types of raw material powders are uniformly distributed, and the nano Y2O3 powder is uniformly attached to the surface of the other micron powders.

[0046] The above titanium alloy powder is used for additive manufacturing, and the steps are as follows:

[0047] (1) Establish a printing model, import a selected area laser melting device to generate a processing preparation program;

[0048] (2) Use pure titanium as the substrate, clean and polish the surface of the substrate, and then fix it in the forming cabin of the selected area laser melting device;

[0049] (3) Close the cabin door, and use inert gas (Ar gas) to wash the air in the cabin;

[0050] (4) running the processing preparation program, according to the preset scanning path, melting the titanium alloy powder laid on the powder bed layer by layer, completing the additive manufacturing of the three-dimensional titanium alloy component;

[0051] (5) after printing, taking out the substrate and the titanium alloy component deposited on the surface of the substrate;

[0052] (6) machining the titanium alloy component, and performing organization characterization and other analysis tests.

[0053] The titanium alloy prepared in the embodiment has the following chemical composition and mass percentage: 3% of Fe element, 0.4% of O element, and the balance of Ti; and Y element is precipitated in the additive manufacturing process.

[0054] Further, in the additive manufacturing process of the titanium alloy component, the oxygen content in the forming cabin is less than 100 ppm, high-purity argon is used for gas washing, and the gas washing is continuously maintained during the deposition process to maintain a low-oxygen atmosphere in the cabin, so as to eliminate the influence of oxygen content error.

[0055] Further, in the additive manufacturing process of the titanium alloy component, the laser spot diameter is 60 μm, the laser power is 210 W, the scanning speed is 1150 mm / s, the single-layer deposition thickness is 30 μm, the overlap rate is 40%, and the substrate is preheated to 200°C.

[0056] Further, the laser scanning mode adopts a single-layer parallel line scanning path, after completing one layer of deposition, the scanning path of the next layer is rotated clockwise by 90° relative to the scanning path of the previous layer; in particular, the embodiment designs a periodic remelting process, which is performed every 2 layers on the basis of the given laser scanning path, and the remelting process parameters are as follows: laser power 120 W, scanning speed 1200 mm / s, spot overlap rate 0-10%, and scanning path single-layer parallel line scanning. The remelting process is directly performed after the completion of the previous layer, without powder laying. The finally prepared titanium alloy sample has a size of 20*10*10 mm.

[0057] On the basis of the conventional laser selective melting process, the embodiment introduces a periodic remelting process, which improves the microstructure characteristics of the titanium alloy and refines the grain structure. At the same time, the introduction of nano Y2O3 particles realizes the dual effects of grain refinement and intergranular brittleness relief. The alloy sample prepared in the embodiment shows excellent matching of strength and plasticity, the tensile strength is ≥1100 MPa, and the elongation after fracture is ≥15%, which further improves the comprehensive mechanical properties of the Ti-O-Fe alloy.

[0058] Comparative Example 1

[0059] A titanium alloy powder material is prepared, raw materials including pure Ti powder, pure Fe powder, TiO2 powder. The mass percentage of each type of raw material powder is as follows: pure Fe powder is 3%, TiO2 powder is 1%, and the balance is pure Ti powder.

[0060] The pure Ti powder in the titanium alloy powder is 15-53 μm spherical powder, the pure Fe powder is 0.5-1 μm spherical powder, and the TiO2 powder is 0.5-1 μm spherical powder.

[0061] The titanium alloy powder material is obtained according to the following steps:

[0062] (1) The pure Ti powder, pure Fe powder and TiO2 powder are mixed. In order to achieve good powder mixing effect and dispersion effect, a multi-stage powder mixing process is carried out using a sound resonance device, and the steps are as follows:

[0063] High-frequency mixing, frequency 90hz, acceleration 80g, mixing time 6min, the purpose is to break the agglomeration of fine powder and improve the uniformity of the next step.

[0064] Low-frequency mixing, frequency 60hz, acceleration 80g, mixing time 20min, the purpose is to uniformly disperse the raw material powder.

[0065] (2) The mixed titanium alloy powder is placed in a vacuum drying oven for drying treatment, the drying oven temperature is 80-100℃, and the drying time is 3-6h.

[0066] The above titanium alloy powder is used for additive manufacturing, and the steps are as follows:

[0067] (1) Establish a printing model, import a selected area laser melting device to generate a processing preparation program;

[0068] (2) Use pure titanium as the substrate, clean and polish the surface of the substrate, and then fix it in the forming cabin of the selected area laser melting device;

[0069] (3) Close the cabin door, and use inert gas (Ar gas) to wash the air in the cabin;

[0070] (4) Run the processing preparation program, and according to the preset scanning path, melt the titanium alloy powder laid on the powder bed layer by layer, complete the additive manufacturing of the three-dimensional titanium alloy component;

[0071] (5) After printing, take out the substrate and the titanium alloy component deposited on the surface of the substrate;

[0072] (6) Machine cut the titanium alloy component, and perform organization characterization and other analysis tests.

[0073] The titanium alloy prepared in the embodiment has the following chemical composition and mass percentage: 3% of Fe element, 0.4% of O element, and the balance of Ti.

[0074] Further, in the additive manufacturing process of the titanium alloy component, the oxygen content in the forming cabin is less than 100 ppm, high-purity argon is used for gas washing, and slow and continuous gas washing is performed during the deposition process to maintain a low-oxygen atmosphere in the cabin, so as to eliminate the influence of oxygen content error.

[0075] Further, in the additive manufacturing process of the titanium alloy component, the laser spot diameter is 60 μm, the laser power is 210 W, the scanning speed is 1150 mm / s, the single-layer deposition thickness is 30 μm, the overlap rate is 40%, and the substrate is preheated to 200°C.

[0076] Further, the laser scanning mode adopts a single-layer parallel line scanning path, and after completing the deposition of one layer, the scanning path of the next layer is rotated clockwise by 90° relative to the scanning path of the previous layer. The finally prepared titanium alloy sample has a size of 20*10*10 mm.

[0077] By adding nano Y2O3 particles in the powder raw material and introducing a periodic remelting process in the additive manufacturing method in embodiment 1, the microstructure characteristics of Ti-O-Fe are further improved; the prepared sample of comparative example 1 (other manufacturing steps are the same) without adding nano Y2O3 particles and without introducing a periodic remelting process is compared.

[0078] As shown in Figure 2 The additive manufacturing method provided by the application successfully improves the grain size of the Ti-O-Fe bulk sample; as can be seen, after adding nano Y2O3 particles and introducing a periodic remelting process, the α and β laths in the titanium alloy are obviously refined, and the room temperature size is about 0.5-1 μm. The advantage of the application lies in that the introduction of Y2O3 particles plays a role in enhancing heterogeneous nucleation at the high-temperature phase transition stage, so that the original β grains are refined, and then the refinement of the α and β phases at room temperature is greatly promoted. In addition, by using a low-energy-density additive process, i.e., the optimization parameters of low laser power + fast scanning speed, a near-α' strong non-equilibrium microstructure is obtained, and through the periodic remelting process, the non-equilibrium microstructure is quickly decomposed into equilibrium α+β microstructure, so that the microstructure is finely controlled, and the microsize of the lath microstructure is effectively reduced, so that the purpose of refining the microstructure is achieved.

[0079] In addition, compared with the titanium alloy component prepared in comparative example 1, the room temperature tensile properties of the titanium alloy component prepared in embodiment 1 are comprehensively improved. From Figure 3It can be seen that the Ti-O-Fe bulk sample prepared by the method of the present application greatly improves the elongation of the alloy sample without reducing the tensile strength, and realizes the improvement of the strength and toughness of the Ti-O-Fe alloy. The performance improvement benefits from the substantial refinement of the α+β room temperature dual-phase structure, and the effective improvement of the ductility of the alloy, and the precipitation of nano Y2O3 particles in the process of L→β phase transition of the titanium alloy, effectively alleviates the strong segregation behavior of O at the grain boundary, improves the intergranular brittleness of the alloy, and realizes the high strength and toughness of the Ti-O-Fe alloy.

[0080] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, and they should be covered in the scope of the claims of the present application.

Claims

1. A titanium alloy powder suitable for use in laser selective melting additive manufacturing, characterized in that, The titanium alloy powder is mixed by pure Ti powder, pure Fe powder, TiO2 powder and Y2O3 powder; The Y2O3 powder is uniformly attached to the surface of the pure Ti powder, the pure Fe powder and the TiO2 powder to achieve nanoscale dispersion and regulate the distribution of oxygen elements, and avoid the brittle of grain boundary.

2. The titanium alloy powder of claim 1, wherein, The titanium alloy powder comprises, by mass percentage, 2.7-3.5% of pure Fe powder, 0.9-1.2% of TiO2 powder, 0.1-0.2% of Y2O3 powder, and the balance of pure Ti powder. The pure Ti powder is a spherical powder with a size of 15-53 μm, the pure Fe powder is a spherical powder with a size of 0.5-1 μm, the TiO2 powder is a spherical powder with a size of 0.5-1 μm, and the Y2O3 powder is a non-spherical powder with a size of 10-50 nm.

3. A method of producing a titanium alloy powder as claimed in any one of claims 1 to 2, characterized in that, The method comprises the following steps: (1) adding the pure Ti powder, the pure Fe powder, the TiO2 powder and the Y2O3 powder into a mixing device according to a preset ratio, and performing multi-stage vibration mixing to uniformly attach the Y2O3 powder to the surface of the other powders; (2) performing vacuum drying on the mixed powder to remove moisture and stabilize the powder structure.

4. The production method according to claim 3, characterized by, The multi-stage vibration mixing in the step (1) is specifically as follows: in the high-frequency mixing stage, a frequency of 90 Hz, an acceleration of 80 g and a time of 6 min are adopted to disperse Y2O3 nanoparticles; and in the medium-low frequency mixing stage, a frequency of 60 Hz, an acceleration of 80 g and a time of 20 min are adopted to uniformly adhere Y2O3 to the surface of the other powders.

5. The preparation method according to claim 3, characterized in that, The vacuum drying conditions in the step (2) are as follows: a temperature of 80-100 ℃ and a time of 3-6 h.

6. A method for additive manufacturing of a low-cost high-performance titanium alloy having a fine-grained structure using the titanium alloy powder according to any one of claims 1 to 2, characterized by, The method comprises the following steps: (1) establishing a three-dimensional printing model and generating a laser scanning program; (2) laying a powder bed in a low-oxygen environment and layer-by-layer laser melting the titanium alloy powder; (3) taking out and post-processing the component after the printing is completed.

7. The additive manufacturing method of claim 6, wherein, The low-oxygen environment in the step (2) is that the oxygen content in the forming cabin is less than 100 ppm, high-purity argon is used for gas washing and continuous aeration; The laser process parameters are as follows: a spot diameter of 40-60 μm, a power of 100-300 W, a scanning speed of 1000-1400 mm / s, a single-layer thickness of 20-40 μm, an overlap rate of 40-60%, and preheating the substrate to 150-200 ℃.

8. The additive manufacturing method of claim 6, wherein, The periodic remelting process is adopted in the step (2), and the periodic remelting process is that remelting is performed once immediately after every 2 layers of deposition without powder laying; The remelting parameters are as follows: a laser power of 100-200 W, a scanning speed of 1000-1200 mm / s, an overlap rate of 0-10%, and a scanning path of a single-layer parallel line mode.

9. The additive manufacturing method of claim 6, wherein, The post-processing in the step (3) comprises machining cutting of the component, tissue characterization and mechanical testing.

10. A low cost high performance titanium alloy with a fine grain structure, characterized in that, The low-cost high-performance titanium alloy is prepared by the additive manufacturing method according to any one of claims 6-9, and the chemical composition of the low-cost high-performance titanium alloy is 2.7-3.5% of Fe element, 0.3-0.5% of O element, and the balance of Ti.

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