High-temperature TA15-based composite material based on TiB2 ceramic particle modification and additive manufacturing method thereof

Abstract

The invention relates to the technical field of titanium alloy preparation, in particular to a high-temperature TA15-based composite material based on TiB2 ceramic particle modification and an additive manufacturing method thereof.The TA15 powder and TiB2 powder are dried and then mechanically mixed to obtain mixed powder, and a powder bin is filled with the mixed powder; creating a three-dimensional digital model, slicing the three-dimensional digital model, and obtaining powder parameters and scanning data; the obtained powder parameters and scanning data are imported into 3D printing control software for printing; in the process of melting mixed powder through a laser heat source, TiB2 ceramic particles generate TiB crystal whiskers in situ, the TiB crystal whiskers with the high length-diameter ratio and high orientation are obtained by regulating and controlling the TiB crystal whiskers, grain boundary regulation and control and additive manufacturing process cooperation are achieved, the bottlenecks of high-temperature strength and oxidation resistance of TA15 titanium alloy are solved, and the problems that a traditional titanium alloy casting process is large in number of steps, complex in method and low in cost are solved. And a new thought is provided for solving the problem that the high-temperature obdurability of the titanium alloy cannot meet the ever-increasing use performance requirement.

Description

Technical Field

[0001] The present invention relates to the technical field of titanium alloy preparation, and in particular to a high-temperature TA15-based composite material modified based on TiB2 ceramic particles and an additive manufacturing method thereof. Background Art

[0002] With the rapid development of the new generation of aerospace vehicles, the demand for titanium alloys in key structural components is increasing. However, the service environment is becoming more and more harsh, and the demand for high-temperature and high-strength titanium alloys is becoming more and more urgent. However, due to the limitations of traditional metallurgical principles, the performance and structure of modern titanium alloys cannot fully meet the requirements of high-temperature and high-strength use.

[0003] TA15 titanium alloy (Ti-6.5Al-2Zr-1Mo-1V), a key material for hot-end components of aircraft engines, has excellent medium-temperature performance. However, it faces problems such as insufficient mechanical properties and poor thermal stability in high-temperature environments above 600°C. It has never been able to break through the "thermal barrier temperature" of 600°C and is difficult to meet current usage requirements. The low interfacial energy (<0.8 J / m 2 ) to effectively pin the grain boundaries and hinder dislocation slip, inhibiting the coarsening of the α phase and the weakening of the grain boundaries at high temperatures, and comprehensively achieving a synergistic improvement in high-temperature strength and thermal stability of the structure. Therefore, this patent selects TiB2 ceramic particles to modify high-temperature TA15-based composite materials.

[0004] The traditional preparation of TiB2 / TA15 composite materials relies on high temperature sintering (1200℃ / 8-12h) and other methods, which require ball milling and sintering. The preparation process has many steps, complex methods, long manufacturing cycle, and single structure. The parts of traditional mixed element powder deposition have high density of the constituent powders (TiB2: 4.52 g / cm 3 , TA15: 4.45 g / cm 3 ), morphology and size differences lead to segregation of the initial raw materials (B concentration deviation ± 2 wt.%), generation of coarse and brittle TiBw phase (aspect ratio < 6) at the interface, density of only 93-95%, and difficulty in forming complex structures (such as porous gradients, thin-walled cavities) due to mold limitations; in many cases, poor repeatability of the prepared composite parts, unmelted powder and local chemical inhomogeneities in the produced parts can still be seen, and the high-temperature strength and toughness of titanium alloys cannot meet the growing performance requirements. Summary of the Invention

[0005] In view of the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a high-temperature TA15-based composite material modified based on TiB2 ceramic particles and an additive manufacturing method thereof. The present invention solves the problems of the traditional titanium alloy casting process with many steps, complex methods and single structure through a method of preparing high-strength titanium-based composite materials by in-situ alloying, and provides a new idea for solving the problem that the strength and toughness of titanium alloys cannot meet the growing performance requirements.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A high-temperature TA15-based composite material modified with TiB2 ceramic particles and an additive manufacturing method thereof, comprising the following steps: TA15 powder and TiB2 powder are dried and mixed to obtain mixed powder, and the mixed powder is filled into a powder bin.

[0007] A three-dimensional digital model is created, the three-dimensional digital model is sliced, and powder parameters and scanning data are obtained.

[0008] Import the acquired powder parameters and scanning data into the 3D printing control software, set the printing parameters and start printing.

[0009] During the process of melting the mixed powder with a laser heat source, the TiB2 ceramic particles react in situ to generate TiB whiskers. The generated TiB whiskers are bonded to the matrix through a coherent or semi-coherent interface with low interfacial energy, which enhances the interfacial bonding strength. A high-temperature TA15-based composite material modified based on TiB2 ceramic particles is obtained. The high-temperature TA15-based composite material can maintain its structural stability and functional performance in a high-temperature environment above 600°C.

[0010] By adopting in-situ alloying technology, highly compatible TiB whiskers are directly synthesized in the TA15 titanium alloy matrix through the chemical reaction between Ti and TiB2 (Ti+TiB2→2TiB) during the melting process, avoiding the problem of reinforcement agglomeration in the traditional post-addition method. This process covers the stages of TiB2 decomposition, Ti-B reaction, whisker nucleation growth and solidification, so that TiB whiskers are evenly distributed in the matrix, forming a titanium-based composite material with a tight interface bond, significantly improving mechanical properties (such as high-temperature tensile strength) and thermal stability. The in-situ synthesis method does not require reinforcement pretreatment, simplifies the process while reducing costs and environmental load, and has excellent process universality and can be extended to a variety of alloy systems. Its core advantage is that the reinforcement and the matrix spontaneously form a high-cleanliness interface, effectively reducing defects, and providing an efficient and environmentally friendly solution for the development of high-performance composite materials.

[0011] In a preferred embodiment of the present invention, the cooling rate is increased by water-cooling a stainless steel substrate, and a grain boundary inhibitor Y2O3 is added and adsorbed on the side of TiB to inhibit the lateral coarsening of TiB whiskers, thereby obtaining TiB whiskers with an aspect ratio, wherein the volume fraction of the grain boundary inhibitor Y2O3 is 0.1% to 0.5% of the mixed powder.

[0012] In a preferred embodiment of the present invention, the volume percentage of TiB2 powder in the mixed powder is 0.5%~4.5%. The addition of TiB2 will increase the strength of the TiB2 / TA15 composite material, but will correspondingly reduce the plasticity of the material. When the added content is 4.5% TiB2, the strength of the composite material is as high as 1095.8MPa, but the plasticity is only 2.5%. The effect of too low TiB2 addition (<0.4%) on improving the room temperature and high temperature mechanical properties of the material is limited, and it is difficult to achieve the expected goal of enhancing the material performance by adding ceramic phase.

[0013] In a preferred embodiment of the present invention, the printing parameters are: laser power 1500W, scanning speed 500mm / min, scanning pitch 1mm, print layer thickness 500µm, unidirectional parallel scanning printing path, TA15 powder particle size 25µm-100µm, and TiB2 powder particle size 2µm-13µm. The TA15 powder composition is: 3.3%-4.0% Al, 91.0%-92.2% Ti, 2.0%-2.1% V, 1.5%-1.9% Zr, and 0.9%-1.1% Mo.

[0014] Through the above preferred embodiment, the present invention is based on laser directed energy deposition (LDED) technology, through synchronous powder feeding and dynamic control of laser power (1400W~1600W), scanning speed (450mm / min~550mm / min), layer thickness (450µm~550µm), and scanning spacing (0.8mm~1.2mm), adding grain boundary inhibitors (a trace amount of Y2O3 is adsorbed on the side of TiB to inhibit diffusion), and using Marangoni convection to drive orientation arrangement, unidirectional parallel scanning, and controlling the aspect ratio of the molten pool by the laser spot diameter to form a narrow molten pool to constrain the flow direction, thereby achieving in-situ generation of a molten pool with a high aspect ratio (7 ~19), highly oriented (63%~75%) TiB whiskers, matrix grain size is refined to 0.8μm~1.5μm, and TiB2 agglomeration is suppressed, the density is increased to more than 98%, so that the room temperature and high temperature mechanical properties of the modified alloy are improved significantly, and the service performance under high temperature conditions is upgraded by leaps and bounds, showing excellent temperature-strength synergistic response characteristics, while supporting the integrated near-net forming of conformal cooling flow channel components and gradient functional materials, providing a possibility to overcome the technical difficulties of enhanced phase distribution, high temperature performance and coordinated optimization of complex structures, and also providing a new idea for the problem that the high temperature strength and toughness of titanium alloys cannot meet the growing performance requirements.

[0015] Another object of the present invention is to provide a high-temperature TA15-based composite material modified with TiB2 ceramic particles, obtained by the additive manufacturing method described in any one of the above.

[0016] The core of the present invention is to achieve the unity of uniform distribution of reinforcement phase, interface stability and dense forming through material-process integrated design, providing a reliable material basis for lightweighting of aviation engine components above 600°C.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention mechanically mixes TA15 powder and TiB2 powder after drying to obtain a mixed powder, and then fills the mixed powder into a powder bin; creates a three-dimensional digital model, slices the three-dimensional digital model, obtains powder parameters and scan data, imports the obtained powder parameters and scan data into 3D printing control software, sets printing parameters and performs printing, and after printing, obtains a high-temperature TA15-based composite material modified with TiB2 ceramic particles. The present invention adopts in-situ alloying technology to directly synthesize highly compatible TiB whiskers in the TA15 titanium alloy matrix through the chemical reaction between Ti and TiB2 during the melting process (Ti+TiB2→2TiB), avoiding the reinforcement agglomeration problem of the traditional post-addition method. The process covers the TiB2 decomposition, Ti-B reaction, whisker nucleation growth and solidification stages, so that the TiB whiskers are evenly distributed in the matrix, forming a titanium-based composite material with a tight interface bond, significantly improving mechanical properties and thermal stability. The in-situ synthesis method does not require reinforcement pretreatment, simplifies the process while reducing costs and environmental load, and has excellent process universality and can be expanded to various alloy systems. Its core advantage lies in the spontaneous formation of a high-cleanliness interface between the reinforcement and the matrix, which effectively reduces defects and provides an efficient and environmentally friendly solution for the development of high-performance composite materials.

[0018] 2. TiB2 ceramic particles, through in-situ generation of TiB whiskers, B element grain boundary control, and additive manufacturing processes, systematically address the high-temperature strength, creep resistance, and oxidation resistance bottlenecks of TA15 titanium alloy, from microstructural optimization to macroscopic performance enhancement. The core of this approach is to achieve uniform distribution of the reinforcement phase, interface stability, and dense forming through integrated material-process design, providing a reliable material foundation for lightweighting aircraft engine components above 600°C. High-temperature TA15-based composite materials modified with TiB2 ceramic particles, prepared by additive manufacturing methods, address the problems of traditional titanium alloy casting processes with multiple steps, complex methods, and a single structure, providing a new approach to addressing the problem that the high-temperature strength and toughness of titanium alloys cannot meet the growing performance requirements.

[0019] 3. The addition amount of TiB2 in the titanium alloy prepared by the present invention is 0.5%~4.5%. Different addition amounts of TiB2 also affect its reinforcement effect. When the TiB2 addition amount is low, the number of TiB whiskers generated is small and the distribution is sparse, and the reinforcement effect of TiB whiskers is limited. When the TiB2 addition amount is moderate, the number of TiB whiskers generated is moderate and the distribution is uniform. TiB whiskers can effectively strengthen the matrix without significantly reducing the plasticity and toughness of the alloy. When the TiB2 addition amount is too high, the number of TiB whiskers generated is too large, which may cause whisker aggregation or uneven distribution. Excessive TiB whiskers will cut the matrix and reduce the plasticity and toughness of the alloy.

[0020] 4. The present invention optimizes the formation of TiB2 in the alloy and enhances its performance through process parameters. The laser power is set at 1400W-1600W, the scanning speed is 450mm / min-550mm / min, the layer thickness is 450µm-550µm, and the scanning pitch is 0.8mm-1.2mm. Excessive laser power leads to excessively high melt pool temperatures, which can cause overmelting of the titanium matrix, grain coarsening, and reduced mechanical properties. High power leads to an expansion of the heat-affected zone and increased residual stress, potentially inducing cracks or deformation. Excessive laser power leads to incomplete decomposition of TiB2, insufficient boron release, insufficient TiB whisker formation, and uneven nucleation and growth, compromising the reinforcement effect. Excessively rapid cooling rates can lead to incomplete TiB2 decomposition, insufficient time for TiB whisker nucleation and growth, resulting in smaller and more unevenly distributed whiskers. Rapid cooling can lead to the formation of non-equilibrium phases, affecting the material's structure and properties. Excessively slow scanning speeds reduce the cooling rate, resulting in grain coarsening and reduced strength and toughness. Excessive layer thickness can lead to uneven melt pool depth and uneven distribution of TiB whiskers in the thickness direction, affecting the reinforcement effect. Excessive layer thickness can lead to increased heat accumulation, which may cause the melt pool temperature to be too high, excessive decomposition of TiB2, or dissolution of TiB whiskers. Excessive scanning spacing can lead to unfused melt channels, forming pores and reducing density. Excessive scanning spacing can lead to increased heat accumulation, which may cause the melt pool temperature to be too high, excessive decomposition of TiB2, or dissolution of TiB whiskers. The comparative advantages of using additive manufacturing and traditional methods to prepare high-temperature TA15-based composites are shown in Table 1:

[0021] Table 1 Comparison of the advantages of using additive manufacturing and traditional methods to prepare high-temperature TA15-based composites 11. This invention produces high-aspect-ratio TiB whiskers through rapid solidification and the addition of a grain boundary inhibitor (a trace amount of Y2O3 (0.1-0.5 vol.%) adsorbed on the sides of the TiB to inhibit diffusion). These whiskers surpass low-aspect-ratio whiskers in strength, toughness, and high-temperature performance through the synergistic effects of geometric advantages (grain spanning and directional alignment) and multi-scale strengthening mechanisms (load transfer, crack bridging, and dislocation pinning). The directional solidification characteristics of the LDED process further amplify these advantages, making the material irreplaceable in extreme environment applications such as aerospace and the nuclear industry.

[0022] 12. The higher power (1400W-1600W) employed in this invention increases the melt pool temperature gradient and enhances Marangoni convection. Strong convection vortices form within the melt pool, driving the TiB2 particles to decompose and generate TiBW that align along the flow direction, typically aligned with the laser scanning direction. This results in highly oriented TiBW, which aligns parallel to the tensile axis during tensile testing. The control strategy for enhancing Marangoni convection is as follows:

[0023] ①Use unidirectional parallel scanning without crossing or rotating to ensure the consistency of the flow direction; ②Control the aspect ratio of the molten pool by laser power to form a narrow and long molten pool to constrain the flow direction.

[0024] 7. The high-temperature TA15-based composite material modified based on TiB2 ceramic particles prepared by the present invention uses TiB2 as a reinforcing phase, which can significantly improve the high-temperature properties of the alloy, such as tensile strength, yield strength and fatigue resistance, thereby meeting higher usage requirements. The hardness of TiB2 can effectively improve the wear resistance of the alloy and extend its service life, making it particularly suitable for applications in high-wear environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : are particle size distribution diagrams, where (a) is the particle size distribution diagram of TA15 powder and (b) is the particle size distribution diagram of TiB2 powder.

[0026] Figure 2 are SEM images, where (a) and (b) are SEM images of TA15 powder at different magnifications, and (c) and (d) are SEM images of TiB2 powder at different magnifications.

[0027] Figure 3 Metallographic structure diagram, where (a) is the metallographic structure of pure TA15 titanium alloy, (b) is the metallographic structure of TA15 titanium alloy containing 0.5% TiB2, (c) is the metallographic structure of TA15 titanium alloy containing 2.5% TiB2, and (d) is the metallographic structure of TA15 titanium alloy containing 4.5% TiB2.

[0028] Figure 4 : are tensile performance diagrams, wherein (a) is the tensile performance diagram of the materials of Control Example 1, Example 1, Example 2 and Example 3 at room temperature, with three parallels made for each sample; (b) is the tensile performance diagram of the materials of Control Example 1 and Example 1 at 550°C, with two parallels made for each sample; and (c) is the tensile performance diagram of the materials of Control Example 1 and Example 1 at 750°C, with two parallels made for each sample. DETAILED DESCRIPTION

[0029] The following is a detailed description of the technical solutions in the embodiments of the present invention, using preferred embodiments and accompanying drawings in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] It should be noted that all professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0031] Example 1 An additive manufacturing method for high-temperature TA15 titanium alloy modified with TiB2 ceramic particles comprises the following steps: (1) Raw material preparation: Select TA15 and TiB2 powders that meet the requirements and dry them to remove moisture from the powder to ensure the quality of the powder and the printing effect. Then perform a simple mechanical mixing and fill the powder bin. Calculated by volume percentage, the composition of TA15 and TiB2 is 99.5% TA15 and 0.5% TiB2.

[0032] (2) Loading the model: Setting up the printer for printing: The 3D digital model created by the CAD software of a rectangular block with a size of 30mm×15mm×30mm was cut into multiple layers by slicing software, representing the various layers required to form the part. The material was deposited onto the base through a nozzle mounted on a multi-axis arm. The metal material supplied to the nozzle was provided in powder form. During the deposition process, the laser heat source melted the material simultaneously according to the set process parameters, including the laser power of 1500W, the scanning speed of 500mm / min, the printing layer thickness of 500µm, the scanning spacing of 1mm, and the scanning mode of unidirectional parallel scanning to enhance the consistency of the flow direction. This process was repeated until each layer solidified and the object was created. In addition, during the deposition process, the cooling rate was increased by water-cooling the stainless steel substrate. The operating conditions of the water-cooling stainless steel substrate were: water cooling was turned on throughout the process from the first layer deposition to the end of printing, and the circulating cooling water temperature was 10℃.

[0033] (3) Inspection and evaluation: The formed parts were processed into 5mm×5mm×2mm specimens by wire cutting machine, and polished step by step on 80#, 400#, 600#, 800#, 1000#, 1200#, 1500#, and 2000# sandpaper, polished with silica polishing liquid, and corroded with Kroll etching liquid. The Kroll etching liquid was 5% HF, 10% HNO3 and 85% H2O by volume. The microstructure was observed using a scanning electron microscope.

[0034] Example 2 An additive manufacturing method for high-temperature TA15 titanium alloy modified with TiB2 ceramic particles comprises the following steps: (1) Raw material preparation: Select TA15 and TiB2 powders that meet the requirements and dry them to remove moisture from the powder to ensure the quality of the powder and the printing effect. Then perform a simple mechanical mixing and fill the powder bin. Calculated by volume percentage, the composition of TA15 and TiB2 is 97.5% TA15 and 2.5% TiB2.

[0035] (2) Loading the model: Setting up the printer for printing: The 3D digital model created by the CAD software of a rectangular block with a size of 30mm×15mm×30mm was cut into multiple layers using slicing software, representing the various layers required to form the part. The material was deposited onto the base through a nozzle mounted on a multi-axis arm. The metal material supplied to the nozzle was provided in powder form. During the deposition process, the laser heat source melted the material simultaneously according to the set process parameters, including the laser power of 1500W, the scanning speed of 500 mm / min, the printing layer thickness of 500µm, the scanning spacing of 1mm, and the scanning mode of unidirectional parallel scanning to enhance the consistency of the flow direction. This process was repeated until each layer solidified and the object was created. In addition, during the deposition process, the cooling rate was increased by water-cooling the stainless steel substrate. The operating conditions of the water-cooling stainless steel substrate were: water cooling was turned on throughout the process from the first layer deposition to the end of printing, and the circulating cooling water temperature was 10℃.

[0036] (3) Inspection and evaluation: The formed parts were processed into 5mm×5mm×2mm specimens by wire cutting machine, and polished step by step on 80#, 400#, 600#, 800#, 1000#, 1200#, 1500#, and 2000# sandpaper, polished with silica polishing liquid, and corroded with Kroll etching liquid. The Kroll etching liquid was 5% HF, 10% HNO3 and 85% H2O by volume. The microstructure was observed using a scanning electron microscope.

[0037] Example 3 An additive manufacturing method for high-temperature TA15 titanium alloy modified with TiB2 ceramic particles comprises the following steps: (1) Raw material preparation: Select TA15 and TiB2 powders that meet the requirements and dry them to remove moisture from the powder to ensure the quality of the powder and the printing effect. Then perform a simple mechanical mixing and fill the powder bin. Calculated by volume percentage, the composition of TA15 and TiB2 is 95.5% TA15 and 4.5% TiB2.

[0038] (2) Loading the model: Setting up the printer for printing: The 3D digital model created by the CAD software of a rectangular block with a size of 30mm×15mm×30mm was cut into multiple layers using slicing software, representing the various layers required to form the part. The material was deposited onto the base through a nozzle mounted on a multi-axis arm. The metal material supplied to the nozzle was provided in powder form. During the deposition process, the laser heat source melted the material simultaneously according to the set process parameters, including the laser power of 1500W, the scanning speed of 500 mm / min, the printing layer thickness of 500µm, the scanning spacing of 1mm, and the scanning mode of unidirectional parallel scanning to enhance the consistency of the flow direction. This process was repeated until each layer solidified and the object was created. In addition, during the deposition process, the cooling rate was increased by water-cooling the stainless steel substrate. The operating conditions of the water-cooling stainless steel substrate were: water cooling was turned on throughout the process from the first layer deposition to the end of printing, and the circulating cooling water temperature was 10℃.

[0039] (3) Inspection and evaluation: The formed parts were processed into 5mm×5mm×2mm specimens by wire cutting machine, and polished step by step on 80#, 400#, 600#, 800#, 1000#, 1200#, 1500#, and 2000# sandpaper, polished with silica polishing liquid, and corroded with Kroll etching liquid. The Kroll etching liquid was 5% HF, 10% HNO3 and 85% H2O by volume. The microstructure was observed using a scanning electron microscope.

[0040] Example 4 An additive manufacturing method for high-temperature TA15 titanium alloy modified with TiB2 ceramic particles comprises the following steps: (1) Raw material preparation: Select TA15 and TiB2 that meet the requirements, as well as the inhibitor Y2O3 powder, and dry them to remove moisture from the powder to ensure the quality of the powder and the printing effect. Then perform a simple mechanical mixing and fill the powder bin. Calculated by volume percentage, the composition of TA15 and TiB2 is 99.1% TA15, 0.5% TiB2, and 0.4% Y2O3.

[0041] (2) Loading the model: Setting up the printer for printing: The 3D digital model created by the CAD software of a rectangular block with a size of 30mm×15mm×30mm was cut into multiple layers using slicing software, representing the various layers required to form the part. The material was deposited onto the base through a nozzle mounted on a multi-axis arm. The metal material supplied to the nozzle was provided in powder form. During the deposition process, the laser heat source melted the material simultaneously according to the set process parameters, including the laser power of 1500W, the scanning speed of 500 mm / min, the printing layer thickness of 500µm, the scanning spacing of 1mm, and the scanning mode of unidirectional parallel scanning to enhance the consistency of the flow direction. This process was repeated until each layer solidified and the object was created. In addition, during the deposition process, the cooling rate was increased by water-cooling the stainless steel substrate. The operating conditions of the water-cooling stainless steel substrate were: water cooling was turned on throughout the process from the first layer deposition to the end of printing, and the circulating cooling water temperature was 10℃.

[0042] (3) Inspection and evaluation: The formed parts were processed into 5mm×5mm×2mm specimens by wire cutting machine, and polished step by step on 80#, 400#, 600#, 800#, 1000#, 1200#, 1500#, and 2000# sandpaper, polished with silica polishing liquid, and corroded with Kroll etching liquid. The Kroll etching liquid was 5% HF, 10% HNO3 and 85% H2O by volume. The microstructure was observed using a scanning electron microscope.

[0043] Example 5 An additive manufacturing method for high-temperature TA15 titanium alloy modified with TiB2 ceramic particles comprises the following steps: (1) Raw material preparation: Select TA15 and TiB2 powders that meet the requirements and dry them to remove moisture from the powder to ensure the quality of the powder and the printing effect. Then perform a simple mechanical mixing and fill the powder bin. Calculated by volume percentage, the composition of TA15 and TiB2 is 99.5% TA15 and 0.5% TiB2.

[0044] (2) Loading the model: Setting up the printer for printing: The 3D digital model created by the CAD software of a rectangular block with a size of 30mm×15mm×30mm was cut into multiple layers using slicing software, representing the various layers required to form the part. The material was deposited onto the base through a nozzle mounted on a multi-axis arm. The metal material supplied to the nozzle was provided in powder form. During the deposition process, the laser heat source melted the material simultaneously according to the set process parameters, including the laser power of 1600W, the scanning speed of 550mm / min, the printing layer thickness of 550µm, the scanning pitch of 1.2mm, and the scanning mode of unidirectional parallel scanning to enhance the consistency of the flow direction. This process was repeated until each layer solidified and the object was created. In addition, during the deposition process, the cooling rate was increased by using a water-cooled stainless steel substrate. The operating conditions of the water-cooled stainless steel substrate were: water cooling was turned on throughout the process from the first layer deposition to the end of printing, and the circulating cooling water temperature was 25℃.

[0045] (3) Inspection and evaluation: The formed parts were processed into 5mm×5mm×2mm specimens by wire cutting machine, and polished step by step on 80#, 400#, 600#, 800#, 1000#, 1200#, 1500#, and 2000# sandpaper, polished with silica polishing liquid, and corroded with Kroll etching liquid. The Kroll etching liquid was 5% HF, 10% HNO3 and 85% H2O by volume. The microstructure was observed using a scanning electron microscope.

[0046] Comparative Example 1 Additive manufacturing of TA15 titanium alloy without TiB2 addition includes the following steps: (1) Raw material preparation: Only pure TA15 titanium alloy powder (composition: Ti-6.5Al-2Zr-1Mo-1V) was used without adding TiB2, and it was directly dried and filled into the powder bin.

[0047] (2) Loading the model: Setting up the printer for printing: The 3D digital model created by the CAD software of a rectangular block with a size of 30mm×15mm×30mm was cut into multiple layers by slicing software, representing the various layers required to form the part. The material was deposited onto the base through a nozzle mounted on a multi-axis arm. The metal material supplied to the nozzle was provided in powder form. During the deposition process, the laser heat source melted the material simultaneously according to the set process parameters, including the laser power of 1500W, the scanning speed of 500mm / min, the printing layer thickness of 500µm, and the scanning spacing of 1mm. This process was repeated until each layer solidified and the object was created. In addition, during the deposition process, the cooling rate was increased by water-cooling the stainless steel substrate. The operating conditions of the water-cooling stainless steel substrate were: water cooling was turned on throughout the process from the first layer deposition to the end of printing, and the circulating cooling water temperature was 10℃.

[0048] (3) Inspection and evaluation: The formed parts were subjected to the same wire cutting, grinding, polishing and corrosion processes, and the microstructure was observed using a scanning electron microscope.

[0049] Mechanical properties at room temperature: The tensile strength is 943 MPa, which is 11.3% to 16.3% lower than that of Examples 1 to 5.

[0050] Comparative Example 2 Additive manufacturing of TA15 titanium alloy without TiB2 addition (laser power different from control example 1) includes the following steps: (1) Raw material preparation: Only pure TA15 titanium alloy powder (composition: Ti-6.5Al-2Zr-1Mo-1V) was used without adding TiB2, and it was directly dried and filled into the powder bin.

[0051] (2) Loading the model: Setting up the printer for printing: The 3D digital model created by the CAD software of a rectangular block with a size of 30mm×15mm×30mm was cut into multiple layers by slicing software, representing the various layers required to form the part. The material was deposited onto the base through a nozzle mounted on a multi-axis arm. The metal material supplied to the nozzle was provided in powder form. During the deposition process, the laser heat source melted the material simultaneously according to the set process parameters, including the laser power of 1000W, the scanning speed of 500mm / min, the printing layer thickness of 500µm, and the scanning spacing of 1mm. This process was repeated until each layer solidified and the object was created. In addition, during the deposition process, the cooling rate was increased by water-cooling the stainless steel substrate. The operating conditions of the water-cooling stainless steel substrate were: water cooling was turned on throughout the process from the first layer deposition to the end of printing, and the circulating cooling water temperature was 10℃.

[0052] (3) Inspection and evaluation: The formed parts were subjected to the same wire cutting, grinding, polishing and corrosion processes, and the microstructure was observed using a scanning electron microscope.

[0053] (4) Room temperature mechanical properties: The tensile strength is 900 MPa, which is 16.6% to 21.8% lower than that of Examples 1 to 5.

[0054] Comparative Example 3 Additive manufacturing of TA15 titanium alloy without TiB2 addition (laser power different from control example 1) includes the following steps: (1) Raw material preparation: Only pure TA15 titanium alloy powder (composition: Ti-6.5Al-2Zr-1Mo-1V) was used without adding TiB2, and it was directly dried and filled into the powder bin.

[0055] (2) Loading the model: Setting up the printer for printing: The 3D digital model created by the CAD software of a rectangular block with a size of 30mm×15mm×30mm was cut into multiple layers by slicing software, representing the various layers required to form the part. The material was deposited onto the base through a nozzle mounted on a multi-axis arm. The metal material supplied to the nozzle was provided in powder form. During the deposition process, the laser heat source melted the material simultaneously according to the set process parameters, including the laser power of 2000W, the scanning speed of 500mm / min, the printing layer thickness of 500µm, and the scanning spacing of 1mm. This process was repeated until each layer solidified and the object was created. In addition, during the deposition process, the cooling rate was increased by water-cooling the stainless steel substrate. The operating conditions of the water-cooling stainless steel substrate were: water cooling was turned on throughout the process from the first layer deposition to the end of printing, and the circulating cooling water temperature was 10℃.

[0056] (3) Inspection and evaluation: The formed parts were subjected to the same wire cutting, grinding, polishing and corrosion processes, and the microstructure was observed using a scanning electron microscope.

[0057] (4) Room temperature mechanical properties: The tensile strength is 780 MPa, which is 34.5% to 40.5% lower than that of Examples 1 to 5.

[0058] Comparing the examples with Comparative Examples 2 and 3 reveals that the present invention, for the first time, discovered that laser power also affects the room-temperature mechanical properties of the material. Laser powers between 1400W and 1600W exhibit excellent room-temperature mechanical properties. Furthermore, laser power also affects the orientation of the TiBW whiskers. When the laser power is greater than 1600W or less than 1400W, proper Marangoni convection cannot be achieved. Consequently, the powers used in Comparative Documents 2 and 3 cannot produce 63% to 75% highly oriented TiBW whiskers.

[0059] Comparative Example 4 The operation was essentially the same as in Example 1, except that the step of increasing the cooling rate by water-cooling the stainless steel substrate during deposition was omitted. The water-cooling conditions for the stainless steel substrate were as follows: water cooling was enabled throughout the deposition of the first layer and continued until the end of printing, with the circulating cooling water temperature at 10°C. This example demonstrated the effect of "increasing the cooling rate by water-cooling the stainless steel substrate" on the quality of TiB whiskers. The results showed that the TiB whiskers obtained in this comparative example failed to suppress lateral coarsening and failed to achieve a high aspect ratio of 7 to 19.

[0060] Result Analysis TA15 and TiB2 powder particle size distribution is as follows Figure 1As shown, it can be seen that the particle size of TA15 powder is 25µm~100µm, and the particle size of TiB2 powder is 1.5µm~13µm. The particle size distribution is normal, which is suitable for the subsequent LDED powder spreading process. Figure 2 As shown, it can be seen that the powder has high sphericity and uniform distribution.

[0061] Figure 3 Scanning metallographic structures of TA15 composite materials, (a) is pure TA15 titanium alloy, (b) is TA15 titanium alloy containing 0.5% TiB2, (c) is TA15 titanium alloy containing 2.5% TiB2, and (d) is TA15 titanium alloy containing 4.5% TiB2. It can be seen from the figure that TiB whiskers are evenly distributed at the grain boundaries, indicating that the reinforcement phase is well bonded with the matrix, which is conducive to strength improvement.

[0062] Figure 4 The tensile performance diagram of TA15 composite material at different temperatures shows that the tensile strength of TA15 / TiB2 composite material is increased by more than 16.3% at room temperature compared with TA15 material, and the tensile strength is increased by more than 14.3% at the conventional service temperature of 550℃. At the new standard long-term service temperature of 750℃, the tensile strength of TA15 / TiB2 composite material is increased by more than 102.5%, achieving a leap-forward upgrade in service performance under high-temperature conditions and showing excellent temperature-strength synergistic response characteristics.

[0063] In summary, the present invention relates to a high-temperature TA15 titanium alloy modified with TiB2 ceramic particles and its additive manufacturing method. LDED technology utilizes synchronous powder feeding combined with dynamic control of laser power (1400W-1600W), scanning speed (450mm-550mm / min), layer thickness (450μm-550μm), and scanning pitch (0.8mm-1.2mm) to trigger an in-situ reaction (Ti+TiB2→2TiB) in the molten pool, directly generating high-aspect-ratio TiB whiskers while suppressing TiB2 agglomeration. The high aspect ratio ranges from 7 to 19. This process refines the matrix grain size to 0.8μm-1.5μm, achieving a density exceeding 98%. It also achieves a significant improvement in the room-temperature and high-temperature mechanical properties of the TA15 / TiB2 composite. Standardized room-temperature and high-temperature tensile tests demonstrate that the TA15 / TiB2 composite exhibits approximately 16.3% higher tensile strength at room temperature and approximately 14.3% higher tensile strength at the standard service temperature of 550°C compared to TA15. Under the new standard, the long-term service temperature is increased from 550°C to 750°C, and the tensile strength of the TA15 / TiB2 composite at 750°C increases by approximately 102.5%, achieving a significant improvement in service performance under high-temperature conditions and demonstrating excellent temperature-strength synergy. Through material-process synergy optimization, uniform reinforcement distribution, interfacial bonding, and compact forming are achieved, overcoming the bottlenecks of conventional titanium alloys, such as insufficient high-temperature strength, complex fabrication processes, and monolithic structures. This innovative process supports the near-net-net forming of components containing conformal cooling channels and functionally gradient materials, making it suitable for high-temperature, lightweight aerospace engine components. Compared with the traditional post-addition method, in-situ alloying technology reduces production costs and environmental pollution, has process universality, and provides a new path for the development of high-performance titanium-based composite materials.

[0064] It should be noted that when numerical ranges are mentioned in the present invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints may be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0065] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. An additive manufacturing method for high-temperature TA15 titanium alloy modified with TiB2 ceramic particles, characterized in that: The following steps are involved: TA15 powder and TiB2 powder are dried and mixed to obtain a mixed powder, and the mixed powder is filled into a powder bin; Creating a three-dimensional digital model, slicing the three-dimensional digital model, and obtaining powder parameters and scanning data; Import the acquired powder parameters and scanning data into the 3D printing control software, set the printing parameters and start printing; During the laser heat source melting process of the mixed powder, the TiB2 ceramic particles react in situ to generate TiB whiskers. The generated TiB whiskers are bonded to the matrix at a coherent or semi-coherent interface, thereby enhancing the interfacial bonding strength and obtaining a high-temperature TA15-based composite material modified with TiB2 ceramic particles.

2. The additive manufacturing method of high-temperature TA15-based composite materials modified with TiB2 ceramic particles according to claim 1, characterized in that: A grain boundary inhibitor, Y2O3, is added to a mixed powder of TiB2 and TA15. The volume fraction of the grain boundary inhibitor in the mixed powder is 0.1% to 0.5%. The grain boundary inhibitor Y2O3 is adsorbed on the side of TiB to inhibit the lateral coarsening of TiB whiskers. Marangoni convection is used to drive the orientation of TiBW whiskers to obtain high aspect ratio and high orientation TiB whiskers, wherein the high aspect ratio is 7 to 19, the high orientation value is 63% to 75%, and the matrix grain size of the TiB whiskers is 0.8μm to 1.5μm.

3. The additive manufacturing method of high-temperature TA15-based composite materials modified with TiB2 ceramic particles according to claim 1, characterized in that: The volume percentage of TiB2 powder in the mixed powder is 0.5%~4.5%.

4. The additive manufacturing method of high-temperature TA15-based composite materials modified with TiB2 ceramic particles according to claim 1, characterized in that: The printing parameters are: laser power 1400W~1600W, scanning speed 450 mm / min~550 mm / min, and scanning spacing 0.8mm~1.2mm.

5. The additive manufacturing method of high-temperature TA15-based composite materials modified with TiB2 ceramic particles according to claim 1, characterized in that: The printing layer thickness is 450µm~550µm.

6. The additive manufacturing method of high-temperature TA15-based composite materials modified with TiB2 ceramic particles according to claim 1, characterized in that: The printing path is unidirectional parallel scanning.

7. The additive manufacturing method of the high-temperature TA15-based composite material modified with TiB2 ceramic particles according to claim 1, characterized in that: The particle size of TA15 powder is 25µm~100µm, and the particle size of TiB2 powder is 2µm~13µm.

8. The additive manufacturing method of high-temperature TA15-based composite materials modified with TiB2 ceramic particles according to claim 1, characterized in that: The composition of TA15 powder is: 3.3%~4.0%Al, 91.0%~92.2%Ti, 2.0%~2.1%V, 1.5%~1.8%Zr, 0.9%~1.1%Mo.

9. A high-temperature TA15-based composite material modified with TiB2 ceramic particles, produced by the additive manufacturing method according to any one of claims 1 to 8.

10. The high-temperature TA15-based composite material modified with TiB2 ceramic particles according to claim 9, characterized in that: The high-temperature TA15-based composite material modified with TiB2 ceramic particles contains TiB whiskers.

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