Titanium alloy component forming method based on selective laser melting

Abstract

The invention discloses a titanium alloy component forming method based on selective laser melting, and belongs to the technical field of high-temperature titanium alloy surface strengthening. The method comprises the following steps: dividing a three-dimensional model into a plurality of sedimentary layers through slicing software, and dividing the sedimentary layers into an entity area and a contour area; selective laser melting forming is conducted on the solid area in the protective atmosphere; and the contour area is formed in mixed gas of protective gas and nitrogen, the nitrogen is dissolved in a molten pool and reacts with the titanium substrate to generate a TiN strengthening phase, and therefore a strengthening layer is formed on the surface of the component in situ. Through a double-gas-path gas supply system and dynamic atmosphere regulation and control, internal densification and surface layer strengthening are synchronously carried out, forming deformation is effectively relieved, and the surface hardness and wear resistance are remarkably improved.

Description

Technical Field

[0001] This application relates to the field of high-temperature titanium alloy surface strengthening technology, specifically a titanium alloy component forming method based on laser selective melting. Background Technology

[0002] High-temperature titanium alloys are widely used in critical components such as aero-engine blades, compressor disks, and gas turbine parts due to their excellent specific strength and corrosion resistance. In recent years, Selective Laser Melting (SLM), a typical metal additive manufacturing technology, has attracted attention for its ability to efficiently fabricate complex titanium alloy components. However, SLM-processed high-temperature titanium alloy parts still face several key challenges in their application.

[0003] Firstly, the deformation during the forming process is significant. Rapid heating and cooling of the molten pool in the SLM process leads to a substantial accumulation of residual thermal stress, which can easily cause warping deformation of components, especially in large, thin-walled structures. Existing technologies mainly alleviate thermal stress by optimizing the scanning path, setting support structures, or preheating the substrate. However, the support structures often lack sufficient rigidity and are difficult to effectively suppress deformation. Furthermore, removing the support structures in post-processing is complex and can easily affect the surface quality and geometric accuracy of the components.

[0004] Secondly, titanium alloys suffer from insufficient surface wear resistance. Due to the extremely rapid solidification rate during SLM forming, coarse grains and defects easily form on the component surface, resulting in insufficient microhardness and wear resistance, making it difficult to meet the service requirements under high-temperature and high-friction conditions. Traditional surface strengthening methods, such as gas nitriding, plasma nitriding, or shot peening, usually require additional treatment after forming, which not only increases process costs and production cycle but may also damage the surface morphology and geometric accuracy of the component, making them unsuitable for precision components with complex thin walls or internal flow channels. Summary of the Invention

[0005] This application provides a titanium alloy component forming method based on laser selective melting to solve the problem of difficulty in achieving both accuracy and surface properties in high-temperature titanium alloy laser selective melting forming.

[0006] According to one aspect of this application, a method for forming titanium alloy components based on selective laser melting is provided, comprising the following steps: S100 uses slicing software to divide the three-dimensional model of the component to be formed into multiple deposition layers, and divides the deposition layers into an inner solid area and an outer contour area. S200, titanium alloy powder is added to the powder chamber of the laser selective melting and forming equipment, and a titanium alloy plate is used as the forming substrate. The S300 uses a laser selective melting forming device to perform laser selective melting forming of solid areas in a protective gas environment. S400 uses a laser selective melting forming device to perform laser selective melting forming of the contour area in a mixture of protective gas and nitrogen, so that the nitrogen dissolves in the molten pool and reacts with the titanium matrix to generate a TiN strengthening phase, thereby forming a strengthening layer in situ on the surface of the component. S500: After completing the formation of one deposition layer, the substrate is lowered to form the next deposition layer. S600, repeat steps S300~S500 until the component is formed.

[0007] Optionally, the molded substrate is sandblasted, ultrasonically cleaned with acetone, and preheated to 80~300 ℃ before use.

[0008] Optionally, step S100 may further include the following steps: A support structure is added to the part to be formed, and the support structure forms a support area in the deposition layer during the slicing process; In step S400, the support area and the contour area are formed simultaneously.

[0009] Optionally, the support structure may employ a low-density lattice or linear structure.

[0010] Optionally, the laser selective melting forming equipment is equipped with a dual gas supply system, which includes a protective gas channel and a nitrogen channel. In step S300, before performing laser selective melting and forming of the solid area, protective gas is first introduced into the laser selective melting and forming equipment through the protective gas channel; In step S400, before performing laser selective melting and forming of the contour area, protective gas and nitrogen are introduced into the laser selective melting and forming equipment through the protective gas channel and nitrogen channel, respectively.

[0011] Optionally, in the step of introducing protective gas into the laser selective melting and forming equipment through the protective gas channel, the protective gas is argon gas with a purity of ≥99.99%, which is continuously introduced until the oxygen content in the laser selective melting and forming equipment is reduced to below 200ppm.

[0012] Optionally, in the step of introducing protective gas and nitrogen into the laser selective melting and forming equipment through the protective gas channel and nitrogen channel respectively, nitrogen accounts for 5~30 vol.% of the total introduced gas.

[0013] Optionally, the titanium alloy powder used in step S200 has a particle size of 15~53 μm and an oxygen content of no more than 0.15%.

[0014] Optionally, in step S300, the laser in the solid area adopts a checkerboard / striped scanning strategy, with the laser power set to 250-400W, the scanning speed set to 800-1200 mm / s, and the overlap rate set to 50%. In step S400, the laser in the contour area adopts a reciprocating scanning strategy, with the laser power set to 250-350W, the scanning speed set to 500-800 mm / s, and the overlap rate set to 50%.

[0015] Optionally, after the component is formed, the following steps may also be included: S700, remove the support structure and test the depth of the nitrided layer on the component surface.

[0016] In summary, this application includes at least one of the following beneficial technical effects: By dividing the deposited layer into solid and contour regions during the slicing stage and employing differentiated atmosphere control for these two types of regions during the forming process, simultaneous improvement in internal forming accuracy and surface properties was achieved. The solid region melts and solidifies in an inert protective gas, ensuring the density and geometric accuracy of the internal structure and avoiding brittleness caused by excessive nitrogen introduction. The contour region melts in a mixed gas environment of protective gas and nitrogen. Nitrogen dissolves in the molten pool and reacts with the titanium matrix to generate a TiN strengthening phase, directly forming a continuous strengthening layer on the component surface, thus significantly improving surface hardness and wear resistance. Through a layer-by-layer cyclic approach, this method ensures overall dimensional accuracy and forming stability of the component while achieving in-situ strengthening on the surface. This overcomes the bottleneck of traditional laser selective melting processes, which struggle to balance forming accuracy and surface properties, and realizes integrated manufacturing of complex titanium alloy components, achieving both internal densification and surface wear resistance.

[0017] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. A further detailed description of this application will be provided below with reference to the figures. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart of the titanium alloy component forming method based on laser selective melting in this application; Figure 2 The metallographic structure of the nitrided layer on the surface of the component in this application; Figure 3 The electron microstructure of the nitrided layer on the surface of the component in this application is shown. Detailed Implementation

[0019] The embodiments of this application are described in detail below with reference to the accompanying drawings; however, this application may be implemented in a variety of different ways as defined and covered below.

[0020] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0021] This application discloses a method for forming titanium alloy components based on laser selective melting.

[0022] Reference Figure 1 This application provides a method for forming titanium alloy components based on laser selective melting, comprising the following steps: S100 uses slicing software to divide the three-dimensional model of the component to be formed into multiple deposition layers, and divides the deposition layers into an inner solid area and an outer contour area. S200: Titanium alloy powder is added to the powder chamber of the laser selective melting and forming equipment, and a titanium alloy plate is used as the forming substrate. The S300 uses a laser selective melting forming device to perform laser selective melting forming of solid areas in a protective gas environment. S400 uses a laser selective melting forming device to perform laser selective melting forming of the contour area in a mixture of protective gas and nitrogen, so that the nitrogen dissolves in the molten pool and reacts with the titanium matrix to generate a TiN strengthening phase, thereby forming a strengthening layer in situ on the surface of the component. S500: After completing the formation of one deposition layer, the substrate is lowered to form the next deposition layer. S600, repeat steps S300~S500 until the component is formed.

[0023] In step S100, the 3D model of the component to be formed is sliced ​​into multiple deposition layers using slicing software. Each deposition layer is a basic unit for selective laser melting, typically with a thickness on the order of tens of micrometers, used to ensure a balance between geometric accuracy and forming efficiency. During the slicing process, the deposition layers are further divided into an internal solid region and an external contour region. The solid region is used to form the load-bearing parts inside the component, ensuring overall strength and density, while the contour region defines the boundary contour and surface accuracy of the component, playing a crucial role in the final appearance quality. This data partitioning method allows for differentiated control of the internal structure and surface properties at the process level.

[0024] In step S200, titanium alloy powder is added to the powder chamber of the laser selective melting forming equipment, and a titanium alloy plate is used as the forming substrate. The powder is the raw material for forming, and its morphology and chemical composition directly affect the powder spreading quality and the stability of the molten pool; the substrate provides a metallurgical bonding interface for the initial layer and also serves as the supporting foundation for the entire component. In order to obtain a good metallurgical bonding effect, the substrate needs to have a certain degree of cleanliness and flatness to avoid defects during the first layer fusion process.

[0025] In step S300, a laser selective melting forming device is used to melt the solid region in a protective gas environment. The protective gas is introduced to isolate oxygen and water vapor, preventing oxidation of the molten pool and thus maintaining the purity of the titanium alloy microstructure and the density of its internal structure. The key point of this step is to form a continuous and dense solid region through stable laser scanning and sufficient molten pool coverage, ensuring the load-bearing capacity of the component.

[0026] In step S400, during the melting of the contour area, a mixture of protective gas and nitrogen is simultaneously introduced into the forming environment. This allows the nitrogen to dissolve in the high-temperature molten pool and react with the titanium matrix, generating dispersed TiN particles, thereby forming a reinforcing layer in situ on the component surface. This reinforcing layer is metallurgically bonded to the matrix simultaneously, avoiding the adhesion problems that may arise from subsequent separate surface treatment processes. The principle lies in utilizing the solubility and chemical combination properties of nitrogen in liquid titanium to construct a reinforcing phase in the forming boundary region, ensuring both the surface hardness and wear resistance of the component without significantly affecting its internal toughness.

[0027] In step S500, after one layer of deposition is formed, the substrate is moved downwards according to a preset layer thickness, and a new layer of powder is laid on its surface to provide uniform powder bed conditions for the melting and forming of the next layer. Through this cycle of layer-by-layer sinking and powder laying, it is ensured that the component is gradually accumulated in the thickness direction, maintaining the continuity of interlayer geometry and metallurgy.

[0028] In step S600, steps S300 to S500 are repeated until all deposited layers are formed, ultimately resulting in an integral component. During this process, the solid region provides a dense load-bearing framework, while the contour region forms a reinforcing layer under a nitrogen-containing atmosphere, thereby achieving synergistic optimization of internal structure and surface properties during the forming process. In a specific embodiment, the deposited layer thickness can be selected within a suitable medium range, and the substrate is cleaned and moderately preheated before forming, enabling the acquisition of a uniform and dense surface-reinforcing layer while ensuring forming stability.

[0029] In one embodiment, the present application pre-treats and preheats the substrate before forming to further improve the metallurgical bonding quality between the substrate and the first deposited layer, and to reduce thermal stress during the forming process. The substrate is typically made of a titanium alloy material with the same or similar composition to the powder to be formed, such as TC4 alloy plate, to ensure compatibility of interface composition and fusion stability. During the pre-treatment process, the substrate surface is first sandblasted. Sandblasting effectively removes the oxide film and impurities from the surface and creates a certain roughness on the substrate surface, which is beneficial for wetting and mechanical interlocking of the first molten pool, thereby enhancing the metallurgical bonding strength. Subsequently, the sandblasted substrate is ultrasonically cleaned with acetone to further remove residual oil, particles, and minute impurities from the surface, ensuring surface cleanliness.

[0030] After cleaning, the substrate undergoes preheating, typically to a temperature range of 80–300 °C. Appropriate preheating significantly reduces the temperature difference between the substrate and the deposited layer during forming, lowering the thermal gradient formed in the molten pool during rapid solidification, thereby effectively suppressing the accumulation of residual stress and component warping. Preheating also improves powder spreadability on the substrate surface, resulting in a more uniform powder layer and contributing to stable forming of the first scanning trajectory. These substrate pretreatment and preheating measures provide a more reliable forming foundation for subsequent melting of the solid and contour regions, thereby improving the overall forming accuracy and service reliability of the component.

[0031] In one embodiment, this application adds a support structure to the component to be formed during the model slicing stage to ensure the stability of the forming process. The support structure is an auxiliary component pre-designed in 3D modeling or slicing software. Its geometry is converted into a corresponding support area in the slicing data and is generated synchronously with the deposition layer during actual forming. The support structure is mainly distributed in overhanging parts, thin-walled areas, or large-span overhanging areas. Its function is to provide support and heat dissipation channels for local deposition layers, prevent the molten pool from collapsing or warping due to lack of lower support, and at the same time reduce the accumulation of local thermal stress.

[0032] During the forming process, the support area is typically formed synchronously with the contour area, meaning the support structure is deposited while the component boundary layer is melting. This synchronous forming method ensures a stable metallurgical bond between the support and the outer surface of the component, guaranteeing sufficient strength and thermal conductivity for the support throughout the processing. By introducing the support structure, the geometric accuracy of the component can be maintained when forming complex geometries, reducing the probability of forming defects, especially in large-size or overhanging structures. Through this support structure, this application can improve the stability of the additive manufacturing process without changing the part's design shape, ensuring the overall forming quality when the deposited layers are stacked one by one.

[0033] In one embodiment, this application specifies the particular form of the support structure. The support structure employs a low-density lattice or linear geometric design. This design significantly reduces material consumption and simplifies subsequent removal while ensuring basic support and heat conduction. The lattice support forms a support network through small, evenly distributed nodes connected by thin connecting rods, thus providing stable support while maintaining overall lightweight design. The linear support arranges slender strip units along the overhang boundary or span direction of the component, forming a continuous auxiliary skeleton to provide reinforced support for critical areas.

[0034] In another embodiment, the laser selective melting forming equipment of this application is equipped with a dual-gas supply system. This system includes a protective gas channel and a nitrogen channel, capable of separately introducing protective gas or a mixture of protective gas and nitrogen into the forming chamber according to the needs of different forming areas. During the solid region forming step, protective gas is continuously supplied to the forming chamber only through the protective gas channel to ensure that the molten pool melts and solidifies in an inert environment, thereby obtaining a dense and stable internal structure. During the contour region forming step, protective gas and nitrogen are simultaneously supplied to the chamber through both the protective gas channel and the nitrogen channel, allowing the molten pool to melt and solidify under a controlled atmosphere. Nitrogen dissolves in the atmosphere and reacts with the titanium matrix, thereby forming a TiN strengthening phase in situ on the component surface.

[0035] The dual-air supply system allows for differentiated atmosphere control between the solid and contour areas within the same equipment. This maintains the internal density and overall mechanical properties of the component while also enhancing the surface layer. This method of switching atmospheres by region avoids the cumbersome process of additional surface treatment after forming, as is common in traditional methods, achieving simultaneous improvement of surface properties and overall forming.

[0036] Specifically, during the forming process, argon gas with a purity of not less than 99.99% is used as the protective gas. Before forming, this gas is continuously introduced to gradually replace the air in the chamber, reducing the oxygen content in the forming environment to below 200 ppm. The flow rate is also controlled at 20-30 L / min, and the replacement time is 2-5 min. As a chemically stable inert gas, argon can effectively isolate oxygen and water vapor under the high-temperature conditions of the molten pool, preventing oxidation reactions or the formation of oxide inclusions in the molten metal, thereby ensuring the purity of the solidified structure.

[0037] Continuously introducing high-purity argon gas not only establishes a low-oxygen environment in the early stages of forming but also maintains a stable atmosphere within the chamber throughout the forming process, preventing oxygen content increases due to powder splashing, dust, or minor external leaks. In this way, melting of the solid and contour regions under different atmospheric conditions can occur in a stable low-oxygen environment, thereby ensuring the metallurgical quality and forming reliability of the component's interior and surface.

[0038] During selective laser melting of the contour area, protective gas and nitrogen are introduced into the forming chamber through protective gas and nitrogen channels, respectively, ensuring that the volume fraction of nitrogen in the total gas entering the chamber is controlled between 5% and 30%. The total flow rate of the mixed gas is controlled at 20~30 L / min, and the introduction time is 25 min to ensure that the nitrogen concentration in the chamber reaches the target level and remains stable. The amount of nitrogen added within this range can dissolve in the molten pool and react chemically with the titanium matrix to generate dispersed TiN particles, thereby forming a strengthening phase in situ on the surface of the component.

[0039] The purpose of adjusting the nitrogen content within this range is to balance the strengthening effect and forming stability. When the nitrogen ratio is too low, the amount of nitrogen dissolved in the molten pool is insufficient, making it difficult to form a sufficient strengthening phase on the surface, resulting in limited strengthening effect. Conversely, when the nitrogen ratio is too high, it can easily lead to the formation of pores or brittle structures in the molten pool, thereby affecting the quality and mechanical properties of the surface layer. Therefore, by controlling the nitrogen gas fraction between 5% and 30%, the formation of nitrides can be effectively achieved and the stability of the forming process can be maintained, thus ensuring that the component obtains a stable and uniform strengthened layer on the surface.

[0040] This application further incorporates a real-time atmosphere monitoring module and a gas switching controller into the existing dual-gas supply system. The real-time atmosphere monitoring module continuously monitors the oxygen content, nitrogen partial pressure, and gas flow rate within the forming chamber using sensors, transmitting the signals to the controller. The gas switching controller, based on preset process parameters and monitoring results, rapidly switches between or mixes protective gas and nitrogen, ensuring the stable achievement of differentiated atmospheric conditions between the solid region and the contour region. The introduction of this module avoids forming instability caused by gas switching lag or fluctuations in mixing ratios, thereby further improving process controllability and repeatability.

[0041] In another embodiment, this application specifies the particle size range and compositional purity of the titanium alloy powder used for forming. The particle size of the powder is controlled between 15 and 53 μm, and the oxygen content is no more than 0.15%. Setting the particle size range helps to balance powder uniformity and laser melting efficiency. While excessively fine powder can improve surface smoothness, it is prone to splashing or sintering and agglomeration under laser irradiation, leading to unstable forming; while excessively coarse powder is difficult to completely melt within a single layer thickness, easily forming incomplete fusion defects between layers. Therefore, controlling the powder particle size within the range of 15 to 53 μm achieves a balance between forming efficiency and density, ensuring the uniformity and continuity of the deposited layer. Furthermore, the oxygen content of the powder significantly affects the microstructure and properties after forming. Oxygen acts as an interstitial solid solution atom in titanium alloys; excessively high oxygen content leads to decreased material plasticity and increases the risk of brittle cracking. Therefore, by controlling the oxygen content of the powder to below 0.15%, the molten pool metal can maintain good fluidity and toughness during the forming process, thereby obtaining a microstructure that combines strength and ductility. Through strict control of powder particle size and chemical composition, this application can ensure uniform powder spreading and stable solidification of the molten pool during additive manufacturing, thereby further improving the overall forming quality and service reliability of the components.

[0042] In another embodiment, this application specifies the scanning strategy and process parameters for the solid region and the contour region. The solid region employs a checkerboard or stripe scanning strategy, dividing a large area into several small units or parallel strips, scanning them one by one to effectively disperse heat input and reduce the concentration of residual thermal stress. During scanning of the solid region, the laser power is controlled between 250 and 400 W, the scanning speed is set to 800 to 1200 mm / s, and the overlap rate is 50% to ensure that the molten pool has sufficient melt depth and overlap width, thereby obtaining a dense and continuous internal structure.

[0043] The contour area employs a reciprocating scanning strategy, scanning along the part boundary line in alternating directions. This method ensures the linear accuracy and boundary clarity of the outer contour while reducing surface warping caused by unidirectional heat accumulation. During contour area scanning, the laser power is controlled between 250 and 350 W, the scanning speed is 500 to 800 mm / s, and the overlap rate is also 50%, ensuring stable nitriding reaction conditions while maintaining surface flatness in the molten pool. By using different scanning strategies and process parameters for the solid area and the contour area respectively, the internal density of the component can be balanced with the precision and strengthening effect of the external surface, achieving synergistic optimization of forming efficiency and performance quality.

[0044] In one embodiment, this application further includes a post-processing step after the component is formed. First, the support structure formed on the component is removed. Since the support structure mainly serves to support and conduct heat during the forming process, its geometry is usually low-density. Therefore, after forming, it can be quickly removed by mechanical cutting, vibration impact, or electrical discharge machining without causing significant damage to the main body of the component. After the support is removed, the surface of the component is cleaned to remove residual powder or processing marks, ensuring that the surface condition meets the testing requirements.

[0045] Subsequently, the depth of the nitrided layer on the component surface is tested to verify the thickness and distribution of the TiN strengthening phase generated in situ during the contour forming process. Testing methods may include metallographic microscopy, microhardness gradient analysis, or scanning electron microscopy combined with energy dispersive spectroscopy. These methods can clearly display the metallurgical interface between the nitrided layer and the substrate, and determine the continuity and uniformity of the nitrided layer in the thickness direction. The test results can not only be used to evaluate the rationality of process parameters but also provide reliable quality assurance for practical applications. Through the above post-processing steps, this application ensures that the component possesses both a complete geometric shape and a stable strengthening effect on the surface, thereby meeting the wear resistance and reliability requirements under service conditions.

[0046] Reference Figure 2 and Figure 3 The component prepared in this application can form a continuous nitrided strengthening layer in the contour region. This strengthening layer consists of dispersed TiN particles, and its microhardness can reach 600~800 HV, which is about 50%~100% higher than that of the untreated SLM state, significantly improving the wear resistance and high-temperature oxidation resistance of the component. By adjusting the nitrogen ratio in the mixed gas, the nitrogen content dissolved in the molten pool can be controlled. When the nitrogen content is about 10%, the surface hardness of the alloy is significantly higher than that of the matrix; when the nitrogen content reaches 15%, the hardness improvement effect is optimal and the performance is stable; when the nitrogen content is increased to 20%, the hardness still remains at a high level; while when the nitrogen content exceeds 25%, although the hardness continues to increase, the forming difficulty of additive manufacturing increases significantly, which can easily lead to a decrease in the formability of the component and an increase in defects. Therefore, in actual processes, it is preferable to control the nitrogen content at about 15% to obtain the best balance between strengthening effect and forming stability.

[0047] The implementation principle of the titanium alloy component forming method based on laser selective melting in this application is as follows: During the laser selective melting process, the component to be formed is divided into a solid region and a contour region using data slicing and region segmentation methods, thereby applying differentiated atmosphere control and scanning processes to different regions. The solid region is melted and solidified in an inert gas protective environment to ensure the density of the internal structure and the strength of the matrix, forming the load-bearing skeleton of the component. The contour region is scanned in a mixed atmosphere of protective gas and nitrogen. The nitrogen dissolves in the high-temperature molten pool and reacts chemically with the titanium matrix, precipitating dispersed TiN particles during solidification, directly forming a reinforcing layer on the component surface in situ. Through this method, the component can obtain comprehensive characteristics that combine overall mechanical properties and surface wear resistance during the forming stage.

[0048] A dual-gas supply system ensures flexible atmosphere switching between the solid and contour regions, allowing for targeted optimization of the microstructure and properties of different areas. The high purity and low-oxygen environment of the protective gas maintain the chemical stability of the molten pool metal, while the controlled introduction of nitrogen ensures that the formation and distribution of TiN remain within a stable range. Powder particle size and chemical purity control the powder spreading quality and the metallurgical reaction characteristics of the molten pool, while scanning strategies and parameters further balance internal density, surface precision, and strengthening effect. Ultimately, in the layer-by-layer forming cycle, the solid region gradually builds a dense overall structure, while the contour region continuously forms a TiN-containing strengthening layer. The combination of these two elements forms a titanium alloy component with both high strength and high wear resistance. By constructing a strengthening layer in situ during the forming stage, this application avoids the defects of traditional processes requiring additional surface treatment, achieving integrated process and simultaneous optimization of structure and performance.

[0049] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for forming titanium alloy components based on laser selective melting, characterized in that: Includes the following steps: S100 uses slicing software to divide the three-dimensional model of the component to be formed into multiple deposition layers, and divides the deposition layers into an inner solid area and an outer contour area. S200, titanium alloy powder is added to the powder chamber of the laser selective melting and forming equipment, and a titanium alloy plate is used as the forming substrate. The S300 uses a laser selective melting forming device to perform laser selective melting forming of solid areas in a protective gas environment. S400 uses a laser selective melting forming device to perform laser selective melting forming of the contour area in a mixture of protective gas and nitrogen, so that the nitrogen dissolves in the molten pool and reacts with the titanium matrix to generate a TiN strengthening phase, thereby forming a strengthening layer in situ on the surface of the component. S500: After completing the formation of one deposition layer, the substrate is lowered to prepare for the formation of the next deposition layer. S600, repeat steps S300~S500 until the component is formed.

2. The titanium alloy component forming method based on laser selective melting according to claim 1, characterized in that: Before use, the molded substrate is pretreated by sandblasting and ultrasonic cleaning with acetone, and preheated to 80~300 ℃.

3. The titanium alloy component forming method based on laser selective melting according to claim 2, characterized in that: Step S100 further includes the following steps: A support structure is added to the part to be formed, and the support structure forms a support area in the deposition layer during the slicing process; In step S400, the support area and the contour area are formed simultaneously.

4. The titanium alloy component forming method based on laser selective melting according to claim 3, characterized in that: The supporting structure adopts a low-density lattice or linear structure.

5. The titanium alloy component forming method based on laser selective melting according to claim 1, characterized in that: The laser selective melting forming equipment is equipped with a dual gas supply system, which includes a protective gas channel and a nitrogen channel. In step S300, before performing laser selective melting and forming of the solid area, protective gas is first introduced into the laser selective melting and forming equipment through the protective gas channel; In step S400, before performing laser selective melting and forming of the contour area, protective gas and nitrogen are introduced into the laser selective melting and forming equipment through the protective gas channel and nitrogen channel, respectively.

6. The titanium alloy component forming method based on laser selective melting according to claim 5, characterized in that: In the step of introducing protective gas into the laser selective melting and forming equipment through the protective gas channel, the protective gas is argon gas with a purity of ≥99.99%, which is continuously introduced until the oxygen content in the laser selective melting and forming equipment is reduced to below 200ppm.

7. The titanium alloy component forming method based on laser selective melting according to claim 5, characterized in that: In the step of introducing protective gas and nitrogen into the laser selective melting and forming equipment through the protective gas channel and nitrogen channel respectively, nitrogen accounts for 5~30 vol.% of the total introduced gas.

8. The method for forming titanium alloy components based on laser selective melting according to claim 1, characterized in that: The titanium alloy powder used in step S200 has a particle size of 15~53 μm and an oxygen content of no more than 0.15%.

9. The titanium alloy component forming method based on laser selective melting according to claim 1, characterized in that: In step S300, the laser in the solid area adopts a checkerboard / striped scanning strategy, with the laser power set to 250-400W, the scanning speed set to 800-1200 mm / s, and the overlap rate set to 50%. In step S400, the laser in the contour area adopts a reciprocating scanning strategy, with the laser power set to 250-350W, the scanning speed set to 500-800 mm / s, and the overlap rate set to 50%.

10. The method for forming titanium alloy components based on laser selective melting according to claim 1, characterized in that: After the component is formed, the following steps are also included: S700, remove the support structure and test the depth of the nitrided layer on the component surface.

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