Titanium alloy based on laser powder bed fusion and method of making the same

Abstract

The application relates to the technical field of titanium alloy and discloses a titanium alloy based on laser powder bed melting and a preparation method thereof, the titanium alloy comprises the following elements in percentage by weight: 85-93% of titanium, 4-6% of molybdenum, 2-4% of iron, 1-4% of tin, and inevitable impurities as the balance; the forming state organization of the titanium alloy prepared through laser powder bed melting technology is composed of metastable beta phase and fine and dispersed nanometer omega phase, and the size of the nanometer omega phase is 3-6 nm. The titanium alloy of the application has super-high strength and good plasticity, does not need a subsequent heat treatment process, and realizes low-cost, high-performance and short-process preparation of metastable beta titanium alloy.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy technology, and more specifically, to a titanium alloy based on laser powder bed melting and its preparation method. Background Technology

[0002] Laser powder bed fusion (LPBF) technology, as a representative process of metal additive manufacturing, has shown great potential in aerospace, biomedical, and high-end equipment fields due to its high design freedom, lightweight manufacturing capabilities, and excellent material properties. Titanium alloys, especially metastable β-titanium alloys, have become one of the key material systems for the application of LPBF technology due to their high specific strength, good biocompatibility, and excellent corrosion resistance.

[0003] In recent years, researchers have developed components with tensile strengths exceeding 1000 MPa through composition design and process optimization. These components are made from metastable β-titanium alloys (such as Ti-5Al-5V-5Mo-3Cr and Ti-10V-2Fe-3Al) produced by laser powder bed melting. Despite some progress in the preparation of metastable β-titanium alloys using laser powder bed melting, the following problems remain prominent: Traditional β-titanium alloys rely on precious metal elements such as V, Nb, Ta, and Zr, with raw material costs accounting for more than 60% of manufacturing costs. Furthermore, the preparation process of specialized pre-alloyed powders is complex and expensive, significantly limiting their large-scale application. The rapid cooling process of laser powder bed melting easily forms nano-ω phases (typically <10nm in size). Although this phase can significantly improve the alloy strength (up to 1000MPa or more), the brittle nature of the ω phase results in generally low alloy elongation (approximately 1%), making it extremely prone to brittle fracture and unable to balance high strength and good plasticity. To eliminate the brittle ω phase or obtain an α+β dual-phase structure to optimize strength and plasticity, existing technologies require frequent use of subsequent heat treatment processes such as solution aging and hot isostatic pressing. This not only prolongs the production cycle but also increases process energy consumption and manufacturing costs. At the same time, the heat treatment process can easily lead to problems such as deformation and uneven performance in complex structural parts.

[0004] Based on the shortcomings of the existing technologies, there is an urgent need to develop a low-cost, high-strength and high-plasticity matching metastable β-titanium alloy for laser powder bed melting that does not require subsequent heat treatment. Summary of the Invention

[0005] In view of this, the present invention provides a titanium alloy based on laser powder bed melting and its preparation method, aiming to solve the core pain points of high cost, prominent contradiction between strength and plasticity, and strong dependence on post-processing in the prior art, and promote the large-scale application of additive manufacturing titanium alloys in various fields.

[0006] On the one hand, the present invention provides a titanium alloy based on laser powder bed melting, which, by weight percentage, comprises the following elemental components: 85%-93% titanium, 4%-6% molybdenum, 2%-4% iron, 1%-4% tin, with the balance being unavoidable impurities.

[0007] The morphological structure of the titanium alloy prepared by laser powder bed melting technology consists of a metastable β phase and a finely dispersed nano ω phase with a size of 3-6 nm.

[0008] Preferably, by weight percentage, it comprises the following elemental components: 90% titanium, 5% molybdenum, 3% iron and 2% tin.

[0009] Preferably, by weight percentage, it comprises the following elemental components: 88% titanium, 5% molybdenum, 3% iron, and 4% tin.

[0010] On the other hand, the present invention provides a method for preparing titanium alloys based on laser powder bed melting, comprising the following steps: (1) Raw material preparation: Weigh out 84%-93% titanium, 4%-6% molybdenum, 2%-5% iron, 1%-4% tin and the balance being pure metal powder corresponding to unavoidable impurities by weight percentage.

[0011] After weighing, the powder is sealed, mixed, and then dried.

[0012] (2) Laser powder bed melting preparation: In an inert gas protective environment, after the substrate is preheated, the titanium alloy powder bed is periodically scanned and melted using a laser beam. After each layer is scanned, the substrate is lowered by one layer thickness and the powder feeding cylinder is raised by one layer thickness to complete the laying of a new layer of titanium alloy powder. After each layer is scanned, the laser is controlled to rotate 67° before scanning the next layer. The operation is repeated until all preset slices are completed to obtain a titanium alloy block.

[0013] Preferably, in step (1), the mixing operation is to put the powder into a mixing tank, seal it, and then mix it in a three-dimensional mixer for 10 hours.

[0014] The drying process involves placing the mixed powder in a vacuum oven and drying it at 120°C for 2 hours.

[0015] Preferably, the pure metal powder includes: pure Ti powder with a particle size of 15-53 μm, pure Mo powder with a particle size of 0.8-5 μm, pure Fe powder with a particle size of 15-53 μm, and pure Sn powder with a particle size of 1-10 μm.

[0016] Preferably, in step (2), the substrate preheating temperature is 100℃; the laser scanning process parameters are: laser beam diameter is 62μm, laser power is 180-200W, scanning speed is 800-1200mm / s, powder layer thickness is 20-40μm, and overlap spacing is 80-120μm.

[0017] Preferably, in step (2), the inert gas protection environment is such that the oxygen content in the printing chamber is less than 1500 ppm; after printing is completed, inert gas is continued to be introduced until the titanium alloy block cools to room temperature and is then opened and removed.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The alloy of the present invention has the following characteristics: (1) Ultra-high strength: The alloy has an extremely high yield strength (1358 MPa), which is far greater than that of commonly used metastable β alloys (generally below 900 MPa). The alloy is composed of a metastable β phase and a uniformly dispersed fine (size about 3-6 nm) ω phase. By finely controlling the size and structure of the ω phase, the ω phase provides a high precipitation strengthening effect while maintaining a good elongation.

[0019] (2) Low cost: The alloy raw materials use inexpensive elements such as Fe and Sn to replace expensive alloying elements such as Mo, Nb, V and Ta commonly used in metastable β alloys, which reduces the cost of alloy raw materials; in addition, the alloy raw materials are obtained by in-situ alloying, that is, by directly mixing different pure metal powders to obtain uniform mixed powder, without the need to prepare powder raw materials through pre-alloying, which reduces the raw material processing cost.

[0020] (3) No heat treatment required: Common metastable β titanium alloys generally have low yield strength (<900MPa) and usually require subsequent heat treatment processes to obtain α+β microstructure in order to meet the requirements of high strength and plasticity. This alloy exhibits ultra-high alloy strength and good plasticity after being prepared by laser powder bed melting technology, and no further heat treatment is required. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The room temperature tensile curve of the titanium alloy provided in the embodiments of the present invention; Figure 2 This is the inverse pole figure of the printed titanium alloy along the printing direction in Embodiment 1 of the present invention; Figure 3 This is the metastable β-titanium phase-Z-direction inverse pole diagram of Example 1 of the present invention; Figure 4 The phase composition and distribution of the printed titanium alloy in Example 1 of this invention; Figure 5 This is the grain size distribution of the printed titanium alloy in Embodiment 1 of the present invention; Figure 6 This is the inverse pole figure of the printed titanium alloy along the printing direction in Embodiment 2 of the present invention; Figure 7 This is the metastable β-titanium phase-Z-direction inverse pole diagram of Example 2 of the present invention; Figure 8 The phase composition and distribution of the printed titanium alloy in Example 2 of this invention; Figure 9 This is a grain size distribution diagram of the printed titanium alloy in Embodiment 2 of the present invention; Figure 10 This is the inverse pole figure of the printed titanium alloy in Comparative Example 2 of the present invention along the printing direction; Figure 11 This is the metastable β-titanium phase-Z-direction inverse pole diagram of Comparative Example 2 of the present invention; Figure 12 The phase composition and distribution of the printed titanium alloy in Comparative Example 2 of this invention are shown. Figure 13 This is a grain size distribution diagram of the printed titanium alloy in Comparative Example 2 of the present invention; Figure 14 The dark field morphology, ω phase size statistics, and ω phase aspect ratio statistics of the printed titanium alloy under TEM imaging mode in the embodiments and comparative examples of the present invention are shown. Figure 14 In the image, (a) shows the selected area electron diffraction spots of printed titanium alloys with different Sn contents along the {110} band axis; (b) shows the dark field image morphology of the ω phase obtained after overlaying the ω phase diffraction spots of the printed titanium alloy in (a). Figure 15 Enlarged views of the ω-phase size statistics and ω-phase aspect ratio statistics of the embodiments and comparative examples of the present invention; Figure 15 In the figure, (a) represents the size of the ω phase of the printed titanium alloy with different Sn contents; (b) represents the aspect ratio of the ω phase of the printed titanium alloy with different Sn contents. Figure 16 The room temperature tensile curve of the titanium alloy is provided as a comparative example in this invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Addressing the three major pain points of LPBF metastable β titanium alloys—high cost, a significant contradiction between strength and ductility, and strong dependence on post-processing—an innovative integrated solution of "inexpensive element substitution + in-situ alloying + ω-phase control" was proposed. By designing a Ti-5Mo-3Fe-xSn alloy system, a balance between ultra-high strength and good ductility in the printed state was achieved while reducing raw material costs, eliminating the need for complex post-processing steps. This achievement provides a new paradigm for developing low-cost, high-performance, and short-process LPBF-specific titanium alloys, and has significant practical implications for promoting the large-scale application of additive manufacturing titanium alloys in aerospace structural components, biological implants, and other fields.

[0026] In the following embodiments and comparative examples, Figure 2 This is the inverse pole figure of Example 1. The Ti53-2Sn at the top of the figure is the industry-standard simplified name for Ti-5Mo-3Fe-2Sn titanium alloy. The meaning of Ti53-2Sn is: Ti represents titanium, the matrix element of the titanium alloy; 5 represents 5% by weight of the alloying element molybdenum (Mo); 3 represents 3% by weight of the alloying element iron (Fe); 2Sn represents 2% by weight of the alloying element tin (Sn). Ti53-2Sn corresponds to Example 1. Figure 6 This is the inverse pole figure of Example 2. Similarly, Ti53-4Sn is an abbreviation for Ti-5Mo-3Fe-2Sn, and Ti53-4Sn corresponds to Example 2. Figure 10 This is the inverse pole figure of Comparative Example 2. Ti53 is an abbreviation for Ti-5Mo-3Fe. Ti53 corresponds to Comparative Example 2. Figure 14 , 15 The same applies to other diagrams. Figure 5 , 9 In Figures 1 and 13, the horizontal axis represents the equivalent diameter of the grain (unit: micrometer), and the vertical axis represents the frequency of grain occurrence (normalized percentage). Figure 15 In (a), the horizontal axis represents the particle size of the ω phase (unit: nanometers), and the vertical axis represents the frequency of occurrence of the ω phase particles (normalized percentage). Figure 15In (b), the horizontal axis represents the aspect ratio of the ω phase particles, and the vertical axis represents the frequency of occurrence of the ω phase particles (normalized proportion). Figure 15 The label at the top of (b) is: ω phase average aspect ratio.

[0027] Example 1

[0028] (1) Raw material preparation

[0029] S1. Weigh the following components by weight percentage: titanium 90%, molybdenum 5%, iron 3%, tin 2%, and other impurity elements ≤0.1%.

[0030] S2. Weigh each component of pure metal powder, load it into a mixing container and seal it. Mix it in a three-dimensional mixer for 10 hours to ensure that each component powder is evenly dispersed.

[0031] S3. Take out the mixed powder and place it in a vacuum oven at 120°C for 2 hours to keep the powder dry, then cool it to room temperature and take it out.

[0032] (2) Preparation of titanium alloy by laser powder bed melting

[0033] S1. Confirm that the laser powder bed melting equipment is in normal working condition. Perform necessary calibration and maintenance before printing, including powder cleaning, filter replacement, doctor blade adjustment, substrate leveling, etc.

[0034] S2. Place the mixed powder raw materials into the powder feeding cylinder of the laser powder bed melting equipment.

[0035] S3. Preheat the substrate of the laser powder bed melting equipment to 100°C, and fill the printing chamber with inert gas to keep the oxygen content in the printing chamber less than 1500ppm.

[0036] S4. Adjust the laser beam diameter to 62μm, laser power to 200W, scanning speed to 1000mm / s, layer thickness to 30μm, and overlap spacing to 100μm. Under an inert gas protective environment, use the laser beam to periodically scan and melt the titanium alloy powder bed.

[0037] S5. After each layer is scanned, the substrate is lowered by one layer thickness, and the powder feeding cylinder is raised by one layer thickness. A scraper is used to reciprocate to complete the laying of a new layer of titanium alloy powder. After each layer is scanned, the laser is controlled to rotate 67° before scanning the next layer. This operation is repeated until all preset slices are completed, and finally a titanium alloy block with the target size is obtained by layer-by-layer stacking.

[0038] S6. After printing is complete, continue to introduce inert gas until it cools to room temperature, then open the chamber and remove the formed titanium alloy block.

[0039] Example 2

[0040] (1) Raw material preparation

[0041] S1. Weigh the following components by weight percentage: titanium 88%, molybdenum 5%, iron 3%, tin 4%, and other impurity elements ≤0.1%.

[0042] S2. Weigh each component of pure metal powder, load it into a mixing container and seal it. Mix it in a three-dimensional mixer for 10 hours to ensure that each component powder is evenly dispersed.

[0043] S3. Take out the mixed powder and place it in a vacuum oven at 120°C for 2 hours to keep the powder dry, then cool it to room temperature and take it out.

[0044] (2) Preparation of titanium alloy by laser powder bed melting

[0045] S1. Confirm that the laser powder bed melting equipment is in normal working condition. Perform necessary calibration and maintenance before printing, including powder cleaning, filter replacement, doctor blade adjustment, substrate leveling, etc.

[0046] S2. Place the mixed powder raw materials into the powder feeding cylinder of the laser powder bed melting equipment.

[0047] S3. Preheat the substrate of the laser powder bed melting equipment to 100°C, and fill the printing chamber with inert gas to keep the oxygen content in the printing chamber less than 1500ppm.

[0048] S4. Adjust the laser beam diameter to 62μm, laser power to 200W, scanning speed to 1000mm / s, layer thickness to 30μm, and overlap spacing to 100μm. Under an inert gas protective environment, use the laser beam to periodically scan and melt the titanium alloy powder bed.

[0049] S5. After each layer is scanned, the substrate is lowered by one layer thickness, and the powder feeding cylinder is raised by one layer thickness. A scraper is used to reciprocate to complete the laying of a new layer of titanium alloy powder. After each layer is scanned, the laser is controlled to rotate 67° before scanning the next layer. This operation is repeated until all preset slices are completed, and finally a titanium alloy block with the target size is obtained by layer-by-layer stacking.

[0050] S6. After printing is complete, continue to introduce inert gas until it cools to room temperature, then open the chamber and remove the formed titanium alloy block.

[0051] Experimental results: The mechanical properties of the titanium alloys prepared in Examples 1 and 2 were tested in accordance with the national standard GB / T 228.1-2010 "Metallic materials, tensile testing - Part 1: Room temperature test method". Figure 1The tensile mechanical properties of the Ti-5Mo-3Fe-2Sn and Ti-5Mo-3Fe-4Sn alloys prepared in Examples 1 and 2 were verified. Compared with the comparative examples, the tensile yield strength, tensile strength and tensile plasticity of the alloys in Examples 1 and 2 were significantly improved. The tensile mechanical properties of the samples in the two sets of examples are shown in Table 1. Figure 2 - Figure 13 The microstructure, inverse pole figure, pole figure, and grain statistics of the shaped titanium alloys in Comparative Example 2, Example 1, and Example 2 are presented. Example 1 and Example 2 both exhibit a metastable β phase and a very small amount of α phase. Compared to the mixed columnar and equiaxed grain structure shown in the Comparative Example, Example 1 and Example 2 exhibit a refined equiaxed grain structure. Figure 14 and Figure 15 The figures show the dark-field morphology, ω-phase size statistics, volume fraction, and aspect ratio statistics of the microstructures of Comparative Example 2, Example 1, and Example 2 under TEM imaging mode. Example 1 and Example 2 exhibit a β-phase and diffusely distributed, uniformly distributed nano-precipitated ω-phase. In the comparative example, the average size of the ω-phase is approximately 5.8 nm. Compared to the comparative example, the ω-phase size in Example 1 and Example 2 gradually decreases to approximately 3 nm with increasing Sn content. Furthermore, with increasing Sn content, the volume fraction of the ω-phase in Example 1 and Example 2 significantly decreases, and the aspect ratio slightly decreases, indicating that ω-phase growth is inhibited, resulting in a refinement effect.

[0052] Table 1. Room temperature tensile properties of the alloys in the examples

[0053] Comparative Example 1

[0054] (1) Raw material preparation

[0055] S1. Weigh the following components by weight percentage: titanium 93%, molybdenum 5%, iron 2%, and other impurity elements ≤0.1%.

[0056] S2. Weigh each component of pure metal powder, load it into a mixing container and seal it. Mix it in a three-dimensional mixer for 10 hours to ensure that each component powder is evenly dispersed.

[0057] S3. Take out the mixed powder and place it in a vacuum oven at 120°C for 2 hours to keep the powder dry, then cool it to room temperature and take it out.

[0058] (2) Preparation of titanium alloy by laser powder bed melting

[0059] S1. Confirm that the laser powder bed melting equipment is in normal working condition. Perform necessary calibration and maintenance before printing, including powder cleaning, filter replacement, doctor blade adjustment, substrate leveling, etc.

[0060] S2. Place the mixed powder raw materials into the powder feeding cylinder of the laser powder bed melting equipment.

[0061] S3. Preheat the substrate of the laser powder bed melting equipment to 100°C, and fill the printing chamber with inert gas to keep the oxygen content in the printing chamber less than 1500ppm.

[0062] S4. Adjust the laser beam diameter to 62μm, laser power to 200W, scanning speed to 1000mm / s, layer thickness to 30μm, and overlap spacing to 100μm. Under an inert gas protective environment, use the laser beam to periodically scan and melt the titanium alloy powder bed.

[0063] S5. After each layer is scanned, the substrate is lowered by one layer thickness, and the powder feeding cylinder is raised by one layer thickness. A scraper is used to reciprocate to complete the laying of a new layer of titanium alloy powder. After each layer is scanned, the laser is controlled to rotate 67° before scanning the next layer. This operation is repeated until all preset slices are completed, and finally a titanium alloy block with the target size is obtained by layer-by-layer stacking.

[0064] S6. After printing is complete, continue to introduce inert gas until it cools to room temperature, then open the chamber and remove the formed titanium alloy block.

[0065] Comparative Example 2

[0066] (1) Raw material preparation

[0067] S1. Weigh the following components by weight percentage: titanium 92%, molybdenum 5%, iron 3%, and other impurity elements ≤0.1%.

[0068] S2. Weigh each component of pure metal powder, load it into a mixing container and seal it. Mix it in a three-dimensional mixer for 10 hours to ensure that each component powder is evenly dispersed.

[0069] S3. Take out the mixed powder and place it in a vacuum oven at 120°C for 2 hours to keep the powder dry, then cool it to room temperature and take it out.

[0070] (2) Preparation of titanium alloy by laser powder bed melting

[0071] S1. Confirm that the laser powder bed melting equipment is in normal working condition. Perform necessary calibration and maintenance before printing, including powder cleaning, filter replacement, doctor blade adjustment, substrate leveling, etc.

[0072] S2. Place the mixed powder raw materials into the powder feeding cylinder of the laser powder bed melting equipment.

[0073] S3. Preheat the substrate of the laser powder bed melting equipment to 100°C, and fill the printing chamber with inert gas to keep the oxygen content in the printing chamber less than 1500ppm.

[0074] S4. Adjust the laser beam diameter to 62μm, laser power to 200W, scanning speed to 1000mm / s, layer thickness to 30μm, and overlap spacing to 100μm. Under an inert gas protective environment, use the laser beam to periodically scan and melt the titanium alloy powder bed.

[0075] S5. After each layer is scanned, the substrate is lowered by one layer thickness, and the powder feeding cylinder is raised by one layer thickness. A scraper is used to reciprocate to complete the laying of a new layer of titanium alloy powder. After each layer is scanned, the laser is controlled to rotate 67° before scanning the next layer. This operation is repeated until all preset slices are completed, and finally a titanium alloy block with the target size is obtained by layer-by-layer stacking.

[0076] S6. After printing is complete, continue to introduce inert gas until it cools to room temperature, then open the chamber and remove the formed titanium alloy block.

[0077] Comparative Example 3

[0078] (1) Raw material preparation

[0079] S1. Weigh the following components by weight percentage: titanium 91%, molybdenum 5%, iron 4%, and other impurity elements ≤0.1%.

[0080] S2. Weigh each component of pure metal powder, load it into a mixing container and seal it. Mix it in a three-dimensional mixer for 10 hours to ensure that each component powder is evenly dispersed.

[0081] S3. Take out the mixed powder and place it in a vacuum oven at 120°C for 2 hours to keep the powder dry, then cool it to room temperature and take it out.

[0082] (2) Preparation of titanium alloy by laser powder bed melting

[0083] S1. Confirm that the laser powder bed melting equipment is in normal working condition. Perform necessary calibration and maintenance before printing, including powder cleaning, filter replacement, doctor blade adjustment, substrate leveling, etc.

[0084] S2. Place the mixed powder raw materials into the powder feeding cylinder of the laser powder bed melting equipment.

[0085] S3. Preheat the substrate of the laser powder bed melting equipment to 100°C, and fill the printing chamber with inert gas to keep the oxygen content in the printing chamber less than 1500ppm.

[0086] S4. Adjust the laser beam diameter to 62μm, laser power to 200W, scanning speed to 1000mm / s, layer thickness to 30μm, and overlap spacing to 100μm. Under an inert gas protective environment, use the laser beam to periodically scan and melt the titanium alloy powder bed.

[0087] S5. After each layer is scanned, the substrate is lowered by one layer thickness, and the powder feeding cylinder is raised by one layer thickness. A scraper is used to reciprocate to complete the laying of a new layer of titanium alloy powder. After each layer is scanned, the laser is controlled to rotate 67° before scanning the next layer. This operation is repeated until all preset slices are completed, and finally a titanium alloy block with the target size is obtained by layer-by-layer stacking.

[0088] S6. After printing is complete, continue to introduce inert gas until it cools to room temperature, then open the chamber and remove the formed titanium alloy block.

[0089] Test results

[0090] The mechanical properties of the titanium alloys prepared in Examples 1 and 2 were tested in accordance with the national standard GB / T 228.1-2010 "Metallic materials, tensile testing - Part 1: Room temperature test method". Figure 16 The tensile mechanical properties of Ti-5Mo-2Fe, Ti-5Mo-3Fe, and Ti-5Mo-4Fe prepared in Comparative Examples 1, 2, and 3 were verified. Table 2 shows the specific tensile properties of all comparative examples. All comparative examples exhibited high yield strength but poor plasticity.

[0091] Table 2 Room temperature tensile properties of alloys in the comparative examples

[0092] In summary, this invention introduces inexpensive Fe and Sn elements to form a Ti-Mo-Fe-Sn titanium alloy system, replacing expensive metal elements such as Mo, Nb, and Ta, thereby reducing the cost of alloy raw materials. This invention prepares the raw materials required for laser powder bed melting equipment through in-situ alloying, which reduces the process flow and cost compared to the preparation of pre-alloyed powder raw materials. The Ti-Mo-Fe-Sn alloy prepared by this invention using laser powder bed melting technology exhibits ultra-high strength and good plasticity, significantly improving the problems of insufficient strength and poor plasticity in existing additive manufacturing metastable β titanium alloys, enabling high-strength titanium alloys to meet the performance requirements under extreme working conditions. Furthermore, the Ti-Mo-Fe-Sn alloy prepared by this invention using laser powder bed melting technology does not require subsequent heat treatment or hot isostatic pressing processes; it exhibits good strength-plasticity compatibility in the formed state, reducing post-processing costs.

[0093] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the present invention.

Claims

1. A titanium alloy based on laser powder bed melting, characterized in that, By weight percentage, it comprises the following elements: titanium 85%-93%, molybdenum 4%-6%, iron 2%-4%, tin 1%-4%, with the balance being unavoidable impurities; The morphological structure of the titanium alloy prepared by laser powder bed melting technology consists of a metastable β phase and a finely dispersed nano ω phase with a size of 3-6 nm.

2. The titanium alloy based on laser powder bed melting according to claim 1, characterized in that, By weight percentage, it comprises the following elements: 90% titanium, 5% molybdenum, 3% iron and 2% tin.

3. The titanium alloy based on laser powder bed melting according to claim 1, characterized in that, By weight percentage, it comprises the following elements: titanium 88%, molybdenum 5%, iron 3%, and tin 4%.

4. A method for preparing titanium alloy based on laser powder bed melting as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Raw material preparation: Weigh out 84%-93% titanium, 4%-6% molybdenum, 2%-5% iron, 1%-4% tin and the balance being pure metal powder corresponding to unavoidable impurities by weight percentage; After the weighed powder is sealed, mixed, and then dried; (2) Laser powder bed melting preparation: In an inert gas protective environment, after the substrate is preheated, the titanium alloy powder bed is periodically scanned and melted using a laser beam. After each layer is scanned, the substrate is lowered by one layer thickness and the powder feeding cylinder is raised by one layer thickness to complete the laying of a new layer of titanium alloy powder. After each layer is scanned, the laser is controlled to rotate 67° before scanning the next layer. The operation is repeated until all preset slices are completed to obtain a titanium alloy block.

5. The method for preparing titanium alloys based on laser powder bed melting according to claim 4, characterized in that, In step (1), the mixing operation involves loading the powder into a mixing tank, sealing it, and then mixing it in a three-dimensional mixer for 10 hours. The drying process involves placing the mixed powder in a vacuum oven and drying it at 120°C for 2 hours.

6. The method for preparing titanium alloys based on laser powder bed melting according to claim 4, characterized in that, The pure metal powders include: pure Ti powder with a particle size of 15-53 μm, pure Mo powder with a particle size of 0.8-5 μm, pure Fe powder with a particle size of 15-53 μm, and pure Sn powder with a particle size of 1-10 μm.

7. The method for preparing titanium alloys based on laser powder bed melting according to claim 4, characterized in that, In step (2), the substrate preheating temperature is 100℃; the laser scanning process parameters are: laser beam diameter is 62μm, laser power is 180-200W, scanning speed is 800-1200mm / s, powder layer thickness is 20-40μm, and overlap spacing is 80-120μm.

8. The method for preparing titanium alloys based on laser powder bed melting according to claim 4, characterized in that, In step (2), the inert gas protection environment is such that the oxygen content in the printing chamber is less than 1500ppm; after printing is completed, inert gas is continued to be introduced until the titanium alloy block cools to room temperature and is then opened and removed.

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