A nano-reinforced high-temperature titanium alloy and its directional energy deposition additive manufacturing method

Abstract

This invention discloses a nano-reinforced high-temperature titanium alloy and its directional energy deposition additive manufacturing method, relating to the fields of high-temperature titanium alloy materials and additive manufacturing technology. The method includes the following steps: composition design, raw material weighing, melting and casting (vacuum consumable arc layered gradient melting), powder preparation, laser directional energy deposition (partition scanning + partitioned variable parameter energy input + gradient transition layer and interface control + multi-source sensing real-time monitoring and adaptive temperature field control), and heat treatment. This invention, through synergistic process control throughout the entire process, fully leverages the heat resistance advantages of the nano-second phase while significantly suppressing columnar crystal epitaxial growth, increasing the equiaxed crystal ratio to ≥80%, ultimately obtaining a nano-hierarchical structure with "nano-reinforced phase hierarchically dispersed in fine equiaxed β grains and α / β fine lamellars." The prepared titanium alloy components exhibit a tensile strength of 600~640MPa at 700℃ and an elongation of 25~40%, suitable for high-performance applications such as hot-end components of aerospace engines.

Description

Technical Field

[0001] This invention relates to the field of high-temperature titanium alloy materials and additive manufacturing technology, and in particular to a nano-reinforced high-temperature titanium alloy and its directional energy deposition additive manufacturing method. Background Technology

[0002] High-temperature titanium alloys are key structural materials for hot-end components of high-end equipment such as aero-engines, spacecraft, and advanced gas turbines. Their performance directly determines the thrust-to-weight ratio, service temperature, and lifespan of the equipment. However, as next-generation aero-engines develop towards higher thrust-to-weight ratios, higher turbine inlet temperatures, and lower structural weights, traditional near-alpha Ti-Al-Sn-Zr-Mo-Nb-W-Si high-temperature titanium alloys have gradually revealed their insufficient heat resistance. Their long-term operating temperature is difficult to exceed 700℃, failing to meet the urgent needs of next-generation aero-engines for weight reduction and temperature increase.

[0003] To address the aforementioned challenges, based on the design principles of near-alpha alloys, the development of novel Ti-Al-Zr-Mo-Nb-Sn-Ta-Si high-temperature titanium alloys is a promising approach. Optimizing the high-temperature mechanical properties of these materials through multi-element alloying is one possible solution. For the fabrication of these novel titanium alloys, additive manufacturing technology is the preferred option due to its near-net-shape forming advantages. Selective laser melting (SLM) and directed energy deposition (DED) are the mainstream technologies for forming high-temperature titanium alloys. While SLM offers high forming precision, the thin single-pass cladding layer results in low forming efficiency for large-size components and is prone to severe thermal stress due to repeated melting. In contrast, DED technology, employing coaxial powder feeding and synchronous laser action, offers significant advantages such as high forming efficiency, a wide range of applicable powder particle sizes, and the ability to achieve integrated manufacturing of large-size complex structures, making it the preferred technological path. However, DED forming still faces two major challenges: First, the low thermal conductivity of high-temperature titanium alloys and the high energy density of lasers create a large temperature gradient, leading to thermal stress accumulation and cracking, resulting in poor formability; Second, the uneven distribution of the second phase in traditional ingot preparation causes the second phase to agglomerate at the grain boundaries after DED forming, forming coarse silicides, which seriously deteriorates room temperature plasticity.

[0004] Therefore, developing a new alloy composition and supporting process that matches the characteristics of DED process to synergistically achieve uniform precipitation of nano-reinforcing phases and control of equiaxed crystal structure has become the key to breaking through the bottleneck of additive manufacturing of high-performance large titanium alloy components. Summary of the Invention

[0005] The purpose of this invention is to provide a nano-reinforced high-temperature titanium alloy and its directional energy deposition additive manufacturing method, to solve the problems existing in the prior art, such as insufficient heat resistance of traditional high-temperature titanium alloys, easy cracking during additive manufacturing, second-phase segregation deteriorating room-temperature plasticity, high proportion of columnar crystal regions, and mismatch in formability. This invention improves the strength and plasticity of high-temperature titanium alloys through composition optimization and process synergy. The method of this invention is applicable to the high-performance manufacturing of high-temperature load-bearing components (such as hot-end components of aerospace engines) in the aerospace field.

[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of the present invention: a method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloys, comprising the following steps: Composition Design: The chemical composition of the nano-reinforced high-temperature titanium alloy, by mass percentage, is as follows: Al: 6.0~7.0%, Zr: 8.5~9.5%, Mo: 1.5~2.5%, Nb: 0.8~1.2%, Sn: 3.5~4.5%, Ta: 1.5~2.5%, Si: 0.25~0.45%, with the balance being Ti and unavoidable impurities; Raw material weighing: Calculate and weigh pure titanium raw materials, pure aluminum raw materials, pure tin raw materials, and intermediate alloy particles according to the composition design (using multi-element intermediate alloys instead of single elements). Melting and casting ingots: The raw materials are melted in layers by vacuum consumable arc, cast and quenched in stages to obtain high-temperature titanium alloy ingots (high-temperature titanium alloy ingots reinforced with uniformly dispersed (Ti,Zr)6Si3 particles). Powder preparation: The high-temperature titanium alloy ingot is atomized into high-temperature titanium alloy powder (specifically, high-sphericity, low-oxygen-content high-temperature titanium alloy powder) by plasma rotating electrode. Laser-directed energy deposition: Using the high-temperature titanium alloy powder as raw material, laser-directed energy deposition is performed on the surface of a preheated substrate; during the laser-directed energy deposition process, the heat-mass transfer is dynamically controlled by combining a partitioned scanning strategy, a partitioned variable parameter energy input strategy, a gradient transition layer and interface control strategy, a multi-source sensor real-time monitoring and adaptive temperature field control strategy, so as to suppress cracking and segregation from the source. Heat treatment: The formed part obtained by laser directional energy deposition is subjected to high temperature short-time aging treatment to obtain the nano-reinforced high temperature titanium alloy.

[0007] This invention, through synergistic end-to-end process coordination, fully leverages the heat resistance advantages of the nano-second phase while significantly suppressing the epitaxial growth of columnar crystals, increasing the proportion of equiaxed crystals to ≥80%, ultimately obtaining a nano-hierarchical structure in which "nano-reinforcing phases are hierarchically dispersed in fine equiaxed β grains and α / β fine lamellae". The prepared titanium alloy components exhibit a tensile strength of 600~640MPa at 700℃ and an elongation of 25~40%, making them suitable for high-performance applications such as hot-end components of aerospace engines.

[0008] Furthermore, the pure titanium raw material includes sponge titanium, the pure aluminum raw material includes aluminum granules, the pure tin raw material includes tin granules, and the intermediate alloy particles include Al-Ta intermediate alloy particles, Nb-30Si intermediate alloy particles, and Ti-30Mo-15Nb-5Zr intermediate alloy particles.

[0009] Furthermore, the basic process parameters for laser-directed energy deposition include: laser power of 1800~2800W, scanning speed of 8~15mm / s, powder feed rate of 5~15g / min, spot diameter of 4mm, layer thickness of 0.5mm, and scanning spacing of 3mm.

[0010] Furthermore, the partitioned variable parameter energy input strategy includes: in the high stress risk area, switching from the basic process parameters to a 1500W low power + 7mm / s slow scan mode (other basic process parameters remain unchanged); in the melt pool edge area where silicides are prone to segregation, switching from the basic process parameters to a 200~500Hz high frequency pulse energy input mode (other basic process parameters remain unchanged).

[0011] Furthermore, the high-stress risk area includes the corners.

[0012] Furthermore, the gradient transition layer and interface control strategy includes: before deposition (high-temperature titanium alloy powder), depositing 1-2 layers of low-melting-point, high-plasticity alloy transition layer on the substrate surface as a composition-performance transition layer; in the structural transition region, intermittently adding 0.1-0.3wt% of rare earth elements (Y and / or La) through micro-alloy pulse powder feeding, adding once every 3 layers, and each powder feeding lasts 2-3 seconds.

[0013] Furthermore, the low-melting-point, high-plasticity alloy transition layer includes a TA2 layer and / or a TC1 layer, each with a thickness of 0.3-0.8 mm.

[0014] Furthermore, the structural transition zone includes the flow channel opening and / or corners.

[0015] Furthermore, the multi-source sensing real-time monitoring and adaptive temperature field control strategy includes: throughout the deposition process, through multi-source sensing real-time monitoring and adaptive temperature field control, the interlayer temperature is always maintained within 60% to 80% of the recrystallization temperature of the high-temperature titanium alloy (720~800℃); and the surface strain, the temperature field of the molten pool and its surroundings, and the internal thermal deformation of the substrate are collected in real time. When the strain mutation is >0.5%, the cooling rate at the edge of the molten pool is >80℃ / s, or the interlayer temperature difference is >50℃, the deposition is paused, the induction heating device is activated to heat the risk area to 350~500℃, and the temperature of the deposited area is maintained at 350~500℃ by an infrared heat preservation cover. After confirming that the interlayer temperature difference is ≤30℃, the deposition continues.

[0016] Furthermore, the multi-source sensing real-time monitoring and adaptive temperature field control strategy also includes: after every 5 layers of deposition are completed during the deposition process, the adaptive PID algorithm lowers the reference temperature by 30~50℃ based on heat accumulation. That is, the risk area is heated to 350~500℃, and the temperature of the deposited area is maintained at 350~500℃ by a temperature target lowered by 30~50℃ through an infrared heat preservation cover.

[0017] Furthermore, the laser-directed energy deposition is performed in an inert protective atmosphere.

[0018] Preferably, the method for directional energy deposition additive manufacturing of the nano-reinforced high-temperature titanium alloy includes the following more specific steps: S1. Composition Design: The chemical composition of the nano-reinforced high-temperature titanium alloy, by mass percentage, is: Al: 6.0~7.0%, Zr: 8.5~9.5%, Mo: 1.5~2.5%, Nb: 0.8~1.2%, Sn: 3.5~4.5%, Ta: 1.5~2.5%, Si: 0.25~0.45%, with the balance being Ti and unavoidable impurities; among which Al and Sn solid solution strengthen the α matrix and improve high-temperature creep resistance, Zr... r has the dual function of solid solution strengthening and grain refinement. It strengthens the α phase through lattice distortion and works synergistically with β stabilizing elements to regulate the microstructure. Mo, Nb, and Ta, as β phase stabilizing elements, work synergistically with Zr to refine β grains, promote the formation of equiaxed crystals, and promote the uniform and diffuse precipitation of silicide (Ti,Zr)6Si3. Si forms nanoscale (Ti,Zr)6Si3 silicides with Ti, Zr, etc., which are diffusely distributed at the α / β lamellar interface and within the grains, resulting in high-temperature strengthening and pinning effects. S2. Raw material weighing: Calculate and weigh the raw materials according to the proportion of each element in the nano-reinforced high-temperature titanium alloy to be prepared (i.e., composition design): sponge titanium, aluminum granules, tin granules, and intermediate alloy particles prepared in the form of Al-Ta, Nb-30Si, Ti-30Mo-15Nb-5Zr. S3. Melting and Casting Ingots: A vacuum self-consuming electric arc melting furnace is used, employing a layered gradient charging method: 35~40wt% of sponge titanium, Ti-30Mo-15Nb-5Zr master alloy particles, 10~20wt% of sponge titanium, Nb-30Si master alloy particles, and 10~20wt% of sponge titanium are added sequentially. Finally, uniformly mixed aluminum granules, tin granules, Al-Ta master alloy particles, and the remaining sponge titanium are added. After charging is complete, the furnace door is closed, and the process is allowed to proceed until the vacuum reaches 5×10⁻⁶. -3 Pa ~ 1×10 -2 After Pa, vacuum arc melting is carried out at 1700~1750℃. After the raw materials are completely melted, the power is adjusted to maintain the temperature at 1400~1500℃ and held for 2~4 hours to ensure the homogenization of alloying elements and complete dissolution of silicides. After the holding period, casting is carried out, and then a staged quenching process is adopted. First, it is air-cooled to 800℃, and then immediately water-cooled for quenching to avoid cracking caused by huge phase transformation stress due to direct rapid cooling, thereby obtaining a high-temperature titanium alloy ingot reinforced with uniformly dispersed (Ti,Zr)6Si3 particles. S4. Powder Preparation: The ingot obtained in step S3 is machined into Φ50mm×260mm rods by turning and milling. Alloy powder is prepared by plasma rotating electrode atomization (PREP), with the atomization voltage controlled at 30~35kV, current at 150~180A, rotation speed at 9000~12000r / min, and vacuum degree in the atomization chamber ≤1×10⁻⁶. -2 Pa, after atomization and collection, high-temperature titanium alloy powder with a particle size of 53~150μm was screened out and then vacuum dried at 120℃ for 2h for later use. S5. Laser Directed Energy Deposition (DED): Laser directed energy deposition (DED) is performed on the high-temperature titanium alloy powder obtained in step S4 under an inert protective gas atmosphere. A coaxial powder feeding laser directed energy deposition (DED) system is used, equipped with a real-time monitoring unit (stereoscopic digital image correlation (DIC) system, high-definition infrared thermal imager, distributed fiber optic sensor), an adaptive heating unit (high-frequency induction heating device (specifically a movable high-frequency induction heating head) + infrared heat preservation cover) and an intelligent control unit (edge ​​computing module + adaptive PID control system). Before deposition, the vacuum is first evacuated to 3×10 -3The substrate was preheated to 450-550℃ and held for 5 minutes. Basic process parameters were set, employing a checkerboard-style partitioned scanning strategy (67° rotation between layers with a 10-second delay) and a partitioned variable parameter energy input strategy. In high-stress risk areas (such as corners), a "low power + slow scan" mode was used. In the molten pool edge area where silicides are prone to segregation, a high-frequency pulse energy input mode of 200-500Hz was switched. The interlayer temperature was controlled by a combination of an infrared insulation cover and a high-frequency induction heating device, maintaining it within 60-80% of the alloy recrystallization temperature (720-800℃). For specific areas, gradient transition layers and interface control were implemented: before deposition, 1-2 layers of low-melting-point, high-plasticity alloy transition layers were deposited on the substrate surface as a "composition-performance transition layer." In specific structural transition areas (flow channel openings and / or corners), a "micro-alloy pulse powder feeding" process was used, intermittently adding 0.1-0.3 wt% of the alloy powder. Rare earth elements (Y and / or La) are added once every 3 layers with each powder feeding lasting 2-3 seconds to refine the grains and pin the second phase, preventing it from segregating and coarsening along the grain boundaries. Throughout the deposition process, the DIC system acquires surface strain in real time, an infrared thermal imager records the temperature field of the molten pool and its surroundings, and a fiber optic sensor monitors the internal thermal deformation of the substrate. The data is transmitted to the edge computing unit in real time, and interlayer discrimination is performed based on the AI ​​model (crack judgment threshold: strain mutation > 0.5%, molten pool edge cooling rate > 80℃ / s, or interlayer temperature difference > 50℃). If the deposition layer triggers the threshold, deposition is paused, and a high-frequency induction heating device is activated to heat the risk area (i.e., the area with strain mutation > 0.5%, molten pool edge cooling rate > 80℃ / s, or interlayer temperature difference > 50℃) to 350~500℃, while the temperature of the deposited area is maintained at 350~500℃ by an infrared heat preservation cover. After infrared thermography confirms that the interlayer temperature difference is ≤ 30℃, the laser head returns to normal parameters and continues deposition. During the forming process, every 5 layers of deposition are completed, and the adaptive PID algorithm lowers the reference temperature by 30~50℃ based on heat accumulation. Finally, a particle-reinforced high-temperature titanium alloy forming part with no macroscopic cracks and uniform dispersion of (Ti,Zr)6Si3 is obtained. S6. Heat treatment: After the deposition process in step S5 is completed, the molded part and the substrate are immediately transferred to a vacuum heat treatment furnace under a protective atmosphere. During the transfer, the temperature of the molded part is maintained at ≥300℃. High temperature short aging (750℃ / 1~3h / air cooling, i.e. AC) treatment is adopted to promote the transformation of martensite into α phase, eliminate stress, and precipitate nano-silicide (Ti,Zr)6Si3.

[0019] Furthermore, in step 3, the melting current of the vacuum self-consuming arc melting is 3000~6000A, and the melting voltage is 20~30V.

[0020] Through steps S2, S3, and S4, by using a multi-element master alloy to replace elemental raw materials, the activity of Si element during the melting process is reduced, the segregation of high-melting-point metals is decreased, and the uniformity of alloy element distribution is improved. Before melting, layered gradient charging combined with the layering and isolation effect of sponge titanium allows the master alloy to gradually diffuse in the molten pool, avoiding excessively high local concentrations that could lead to the aggregation of reinforcing phases. A melting temperature of 1700~1750℃ + holding at 1400~1500℃ for 2~4 hours ensures complete melting of raw materials, homogenization of alloy elements, and complete dissolution of silicides. After casting, a staged quenching process is employed (first air-cooled to 800℃, then immediately water-quenched) to avoid cracking caused by the huge phase transformation stress generated by direct rapid cooling (water cooling). This process also promotes the uniform and dispersed precipitation of the (Ti,Zr)6Si3 phase while inhibiting its coarsening and growth, thereby obtaining a high-temperature titanium alloy ingot reinforced with uniformly dispersed (Ti,Zr)6Si3 particles. PREP powder is used, with a powder sphericity ≥98%, oxygen content ≤870ppm, Hall flow rate 22.7~25.5s / 50g (tested according to standard GB / T 1482), and tap density 2.8~3.0g / cm³. 3 (Tested according to standard GB / T 5162), loose density 2.6~2.7 g / cm³ 3 (Tested according to standard GB / T 1479.1) It is superior to the traditional gas atomization method, with a low porosity defect rate, providing high-quality raw materials for subsequent DED molding and ensuring the stability of the mechanical properties of the molded parts.

[0021] After step S5, compared to the traditional DED forming process, the heat distribution of the molten pool is reconstructed through a checkerboard-style partitioned scanning strategy. This avoids stress-oriented accumulation, effectively suppresses the continuous epitaxial growth of columnar grains, weakens texture, and promotes the formation of fine equiaxed grains. Abandoning the fixed power mode, a partitioned variable parameter energy input is adopted based on the part (i.e., component) structure: in high-stress areas, a "low power + slow scan" method is used to reduce the cooling rate, slow down the scanning speed, and combine induction heating with real-time preheating, reducing the local cooling rate to 10. 2 ~10 3The temperature is controlled at ℃ / s to suppress martensitic transformation and reduce thermal stress accumulation. High-frequency pulsed energy breaks up the solute-rich layer in the molten pool edge region where silicides are prone to segregation, promoting uniform nucleation and dispersed distribution of (Ti,Zr)6Si3. Simultaneously, infrared heat preservation and induction heating are used to synergistically regulate the interlayer temperature, maintaining it within 60%~80% of the recrystallization temperature. This improves interlayer bonding quality and inhibits the preferential growth of (Ti,Zr)6Si3 along the interlayer. The introduction of a "composition-performance transition layer" alleviates the thermal expansion mismatch stress between the substrate and the component, preventing interface cracking. Furthermore, a "micro-alloy pulsed powder feeding" technique is used in specific areas to intermittently introduce trace amounts of rare earth elements, refining the grains and pinning the (Ti,Zr)6Si3 phase, preventing its segregation and coarsening along grain boundaries. The entire process utilizes multi-source sensors (DIC, infrared thermal imaging, and fiber optic sensors) to collect data in real time. Through calculation and analysis, when strain, cooling rate, or temperature difference exceeds a threshold, the process is immediately paused and local temperature field control is initiated. Forming continues only after the risk is eliminated, achieving closed-loop intelligent control of the forming process. The final product is a particle-reinforced high-temperature titanium alloy part with no macroscopic cracks and a uniformly dispersed (Ti,Zr)6Si3 particle structure.

[0022] After step S6, once the deposition is complete, the substrate and the molded part are immediately subjected to heat treatment to avoid secondary stress caused by a sudden drop in temperature. A high-temperature short-aging process (750℃ / 1~3h / AC) is used to promote the transformation of martensite into the α phase, eliminate stress, and precipitate nano-silicide (Ti,Zr)6Si3, ultimately obtaining a high-temperature titanium alloy molded part without macroscopic cracks and with both high strength and high plasticity.

[0023] The second technical solution of the present invention: a nano-reinforced high-temperature titanium alloy prepared by the directional energy deposition additive manufacturing method of the above-mentioned nano-reinforced high-temperature titanium alloy.

[0024] The third technical solution of the present invention: an application of the above-mentioned nano-reinforced high-temperature titanium alloy in the preparation of hot-end components of aerospace engines.

[0025] The present invention discloses the following technical effects: (1) The method of this invention is a “shape control-property control” synergistic scheme. Through the synergistic effect of alloy composition design, ingot microstructure control, DED forming parameter optimization and subsequent heat treatment process, the microstructure and properties of high-temperature titanium alloys are effectively controlled. By reasonably controlling the heat input, cooling rate and interlayer temperature distribution during the deposition process, the columnar epitaxial growth and silicide segregation along the grain boundaries are effectively suppressed while ensuring forming stability. A hierarchical structure of “micron-scale matrix + nano-scale reinforcing phase” is formed. This structure not only improves high-temperature strength through nano-reinforcing phase, but also avoids grain boundary embrittlement due to the uniform distribution of reinforcing phase, ensuring room temperature plasticity. It achieves the synergy of high strength at high temperature of 700~750℃ and high toughness at room temperature, which is of great significance for promoting the engineering application of high-temperature titanium alloys in the field of aero-engines.

[0026] (2) The present invention adopts a high temperature melting process of 1700~1750℃ + long temperature holding at 1400~1500℃ + graded quenching process to ensure that the raw materials are completely melted, the alloy elements are homogenized, the silicides are completely dissolved, and the (Ti,Zr)6Si3 phase is uniformly dispersed and precipitated, which solves the problem of coarse agglomeration of silicides in traditional ingots and significantly improves the uniformity of alloy composition and heat resistance stability.

[0027] (3) The present invention uses an intelligent DED forming system to realize real-time monitoring of crack risk and dynamic control of interlayer temperature, so that the interlayer temperature is always maintained within 60-80% of the alloy recrystallization temperature (720~800℃), reducing the stress caused by interlayer thermal expansion mismatch, improving the interface bonding quality, reducing crack risk, and inhibiting the preferential growth of (Ti,Zr)6Si3 along the interlayer.

[0028] (4) The present invention adopts a partitioned variable parameter energy input strategy, abandons the traditional fixed power mode, and dynamically controls heat-mass transfer based on the part structure. Combined with checkerboard partition scanning and interlayer rotation of 67°, it not only relieves thermal stress and suppresses cracks, but also effectively suppresses the continuous epitaxial growth of columnar grains, weakens texture and promotes the formation of fine equiaxed crystals, thereby improving the comprehensive mechanical properties of the formed parts.

[0029] (5) The present invention adopts a gradient transition layer and interface control strategy to introduce a “composition-performance transition layer” between the substrate and the component, which alleviates the interface stress cracking caused by the mismatch of the thermal expansion coefficients of the substrate and the high temperature alloy; in a specific structural transition region, a “micro-alloy pulse powder feeding” process is used to intermittently add trace amounts of rare earth elements (Y and / or La), which refines the grains and pins the (Ti,Zr)6Si3 phase, avoiding its coarsening along the grain boundaries.

[0030] (6) After the forming is completed, an integrated high temperature short-time heat treatment is adopted to avoid secondary stress caused by sudden temperature drop, promote the transformation of martensite into α phase, reduce residual stress, precipitate nano-silicide (Ti,Zr)6Si3, form a hierarchical structure of "micron matrix + nano-reinforcing phase", and synergistically improve strength and plasticity. Attached Figure Description

[0031] 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.

[0032] Figure 1 The diagram shows the components prepared by directional energy deposition additive manufacturing in the various embodiments and comparative examples, wherein (a) is a three-dimensional view of the component and (b) is a top view of the component. In the figure: 1 is the component after deposition, 2 is the flow channel, 3 is the corner region, 4 is the composition-performance transition layer, 5 is the edge region of the molten pool of the deposited layer and the composition-performance transition layer, and 6 is the substrate.

[0033] Figure 2 This is a schematic diagram of the scanning strategy in Example 1.

[0034] Figure 3 The image shows the microstructure of the nano-reinforced high-temperature titanium alloy prepared in Example 1.

[0035] Figure 4 The image shows a macroscopic SEM image of the nano-reinforced high-temperature titanium alloy prepared in Example 1. Detailed Implementation

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0039] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0040] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0041] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0042] In the following embodiments and comparative examples of the present invention, if room temperature is involved, it refers to 20~30°C unless otherwise specified.

[0043] In the following embodiments and comparative examples of this invention, the "%" related to the content of the ingredients all represent mass percentages.

[0044] All raw materials used in the following embodiments and comparative examples of this invention are commercially available products.

[0045] Schematic diagrams of components fabricated by directional energy deposition additive manufacturing in the following embodiments and comparative examples of the present invention are shown below. Figure 1 As shown, (a) is a 3D view of the component, and (b) is a top view of the component. In (a), 1 is the component after deposition (50mm high, with a 0.5mm deposited layer), 2 is the flow channel (flow channel radius R=3mm), 3 is the corner area, 4 is the composition-performance transition layer (divided into 2 layers, the first layer TA2 + the second layer TC1, each layer of the transition layer has a size of 96mm×96mm×0.5mm), 5 is the edge area of ​​the molten pool of the deposited layer and the composition-performance transition layer, and 6 is the substrate (size 100mm×100mm×10mm). The inner and outer diameters of the inner and outer circles of the component are shown in [reference needed]. Figure 1 (b)

[0046] Example 1 A method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloy, comprising the following steps: S1. Composition Design: The chemical composition of the nano-reinforced high-temperature titanium alloy by mass percentage is as follows: Al: 6.5%, Zr: 8.5%, Mo: 1.5%, Nb: 1%, Sn: 3.5%, Ta: 1.5%, Si: 0.35%, with the balance being Ti and unavoidable impurities.

[0047] S2. Raw material weighing: Calculate and weigh the raw materials according to the proportion of each element in the required nano-reinforced high-temperature titanium alloy (i.e., composition design): sponge titanium, aluminum granules, tin granules, and intermediate alloy particles prepared in the form of Al-Ta, Nb-30Si, Ti-30Mo-15Nb-5Zr.

[0048] S3. Melting and Casting Ingots: A vacuum arc remelting furnace is used, employing a layered gradient charging method: 35wt% sponge titanium, Ti-30Mo-15Nb-5Zr master alloy particles, 20wt% sponge titanium, Nb-30Si master alloy particles, and another 20wt% sponge titanium are added sequentially. Finally, a uniformly mixed mixture of aluminum granules, tin granules, Al-Ta master alloy particles, and the remaining sponge titanium are added. After charging is complete, the furnace door is closed, and the vacuum level is allowed to reach 5×10⁻⁶. -3 After Pa, vacuum arc melting was carried out at 1750℃ with a melting current of 5000A and a melting voltage of 30V. After the raw materials were completely melted, the power was adjusted to maintain the temperature at 1450℃ for 3 hours to ensure the homogenization of alloying elements and complete dissolution of silicides. After the holding period, casting was carried out, followed by a staged quenching process. The ingot was first air-cooled to 800℃ and then immediately water-quenched to obtain a high-temperature titanium alloy ingot reinforced with uniformly dispersed (Ti,Zr)6Si3 particles.

[0049] S4. Powder Preparation: The ingot obtained in step S3 is machined into Φ50mm×260mm rods by turning and milling. Alloy powder is prepared using plasma rotating electrode atomization (PREP) method, with the atomization voltage controlled at 30kV, current at 150A, rotation speed at 9000r / min, and vacuum degree in the atomization chamber ≤1×10⁻⁶. -2 Pa, after atomization and collection, was screened to obtain high-temperature titanium alloy powder with a particle size of 53-150 μm (powder sphericity 98%, oxygen content 870 ppm, Hall flow rate 25.10 s / 50 g (GB / T 1482), tap density 2.98 g / cm³). 3 (GB / T 5162) Loose packing density is 2.62 g / cm³ 3 (GB / T 1479.1), vacuum dry at 120℃ for 2 hours for later use.

[0050] S5. Laser Directed Energy Deposition (DED): Laser directed energy deposition (DED) is performed on the high-temperature titanium alloy powder obtained in step S4 under an inert protective gas atmosphere. A coaxial powder feeding laser directed energy deposition (DED) system is used, equipped with a real-time monitoring unit (3D digital image correlation (DIC) system, high-definition infrared thermal imager, distributed fiber optic sensor), an adaptive heating unit (high-frequency induction heating device + infrared heat preservation cover; the front-mounted high-frequency induction heating device is a movable high-frequency induction heating head with a ring coil structure, the inner diameter of the coil being 3:1 to the diameter of the laser spot; the rear-mounted infrared heat preservation cover covers a 12mm area behind the laser application point), and an intelligent control unit (edge ​​computing module + adaptive PID control system). Before deposition, a vacuum of 3×10⁻⁶ is first applied. -3 The substrate was preheated to 500℃ and held for 5 minutes, and high-purity argon gas was used to control the oxygen content to ≤80ppm. Basic process parameters were set (laser power 2200W, scanning speed 12mm / s, powder feed rate 10g / min, spot diameter 4mm, layer thickness 0.5mm, scanning spacing 3mm). Each layer employed a checkerboard-style partitioned scanning strategy (interlayer rotation 67° with a 10-second delay; the specific scanning path for each layer is as follows). Figure 2 (As shown) and a zoned variable parameter energy input strategy. At the corners (high stress risk areas), a "low power (1500W) + slow scan (7mm / s)" mode is adopted (other basic process parameters remain unchanged), reducing the local (corner) cooling rate to 10. 2 ℃ / s, reducing thermal stress accumulation; in the edge region of the molten pool where silicides are prone to segregation, switch to a 300Hz high-frequency pulse energy input mode (other basic process parameters remain unchanged). The interlayer temperature is controlled by the infrared heat preservation cover and the movable induction heating head to keep it at 65%~75% of the alloy recrystallization temperature (750℃). Gradient transition layer and interface control are performed for special areas: before deposition, two low-melting-point, high-plasticity alloy transition layers are deposited on the substrate surface as "composition-performance transition layers" (the first layer is TA2 + the second layer is TC1, each layer is 0.5mm, using the corresponding alloy powder as raw material, and the above basic process parameters and checkerboard partition scanning strategy are used for deposition); in the specific structural transition region (flow channel opening), the "micro-alloy pulse powder feeding" process is used to intermittently add 0.2wt% of rare earth element La, adding once every 3 layers and feeding pure La powder for 2s each time, to achieve grain refinement and pinning of the second phase, avoiding its segregation and coarsening along the grain boundaries.

[0051] Throughout the deposition process, the DIC system acquires surface strain in real time, an infrared thermal imager records the temperature field of the molten pool and its surroundings, and fiber optic sensors monitor the internal thermal deformation of the substrate. This data is transmitted in real time to the edge computing unit, and interlayer discrimination is performed based on an AI model (crack detection thresholds: strain mutation > 0.5%, molten pool edge cooling rate > 80℃ / s, or interlayer temperature difference > 50℃). If the deposition layer triggers the threshold, deposition is paused, and a high-frequency induction heating head is activated to heat the risk area to 450℃, while an infrared insulation cover maintains the temperature of the deposited area at 450℃. Once infrared thermography confirms that the interlayer temperature difference is ≤ 30℃, the laser head returns to normal parameters and deposition continues. During the forming process, after every 5 layers are deposited, the adaptive PID algorithm lowers the base temperature by 30℃ based on heat accumulation (i.e., for layers 1-5, the risk area is heated to 450℃ and the temperature of the deposited area is maintained at 450℃ using an infrared insulation cover; for layers 6-10, the risk area is heated to 420℃ and the temperature of the deposited area is maintained at 420℃ using an infrared insulation cover, and so on). Finally, a particle-reinforced high-temperature titanium alloy forming part with no macroscopic cracks and uniformly dispersed (Ti,Zr)6Si3 was obtained (see schematic diagram of the forming part as shown in the figure). Figure 1 (As shown).

[0052] S6. Heat treatment: After the deposition process in step S5 is completed, the molded part and the substrate are immediately transferred to a vacuum heat treatment furnace under high-purity argon gas. During the transfer, the temperature of the molded part is maintained at ≥300℃, and high-temperature short-time aging (750℃ / 2h / AC) treatment is adopted.

[0053] The SEM image of the microstructure of the nano-reinforced high-temperature titanium alloy component prepared in this embodiment is shown below. Figure 3 As shown, the SEM macroscopic diagram is as follows: Figure 4 As shown, its phase composition consists of fine equiaxed β grains, primary α phase, secondary α phase, and uniformly dispersed nanoscale (Ti,Zr)6Si3 reinforcing phase. The equiaxed β grains have an average particle size of 18 μm and an equiaxed grain ratio of 80%. The primary α phase is lamellar with an average thickness of 0.28 μm. The secondary α phase is dispersed in the β matrix as fine, short flakes with an average thickness of 90 nm. The (Ti,Zr)6Si3 silicide is uniformly dispersed as nanoparticles within the α / β phase and between the lamellar layers, with an average particle size of approximately 20 nm. No coarse silicide phases continuously distributed along grain boundaries were observed. The component has a tensile strength of 1370 MPa and an elongation of 15% at room temperature (tested according to standard GB / T228.1-2021); and a tensile strength of 630 MPa and an elongation of 40% at 700℃ (tested according to standard GB / T228.2-2015). No macroscopic cracks were found inside the component, which has both high strength and high plasticity.

[0054] Comparative Example 1 Same as Example 1, except that in step S5, a traditional unidirectional scanning strategy is used, with interlayer rotation of 67° and a delay of 10 seconds, and no partitioned variable parameter energy input is performed (the rest of the process and parameters remain unchanged).

[0055] The nano-reinforced high-temperature titanium alloy component prepared in this comparative example exhibits a significantly coarser and less uniform phase composition compared to Example 1: the average size of equiaxed β grains increases to approximately 40 μm, and the proportion of equiaxed grains decreases to 45%; the average thickness of the primary α phase increases to 0.45 μm, the secondary α phase coarsens to 150 nm and is unevenly distributed; the average particle size of (Ti,Zr)6Si3 silicide particles increases to 35 nm, and locally coarse (Ti,Zr)6Si3 phases with a size of approximately 140 nm are continuously distributed along grain boundaries. This component exhibits a tensile strength of 1150 MPa and an elongation of 9% at room temperature; and a tensile strength of 540 MPa and an elongation of 28% at 700 °C, with microcracks observed in localized areas within the component. A comparison between Example 1 and this comparative example reveals that, due to the use of a traditional unidirectional scanning strategy without partitioned variable parameter energy input, columnar epitaxial growth and localized silicide segregation are more pronounced, resulting in a decrease in the uniformity of microstructure and properties compared to Example 1.

[0056] Comparative Example 2 Same as Example 1, except that solution aging treatment is used in step S6, specifically 950℃ / 1.5h / AC + 550℃ / 3h / AC (that is, the difference between this comparative example and Example 1 is that only the heat treatment method is changed, and the other processes and parameters remain unchanged).

[0057] The nano-reinforced high-temperature titanium alloy component prepared in this comparative example exhibits a significant change in phase composition compared to Example 1: the β grains coarsen to 45 μm, and the equiaxed grain ratio decreases to 60%; the primary α phase is largely dissolved, leaving only a small amount of coarse α phase with an average thickness of 0.5 μm; the secondary α phase exists in the form of fine needles, with an average thickness reduced to 70 nm, uneven distribution, and disordered orientation; (Ti,Zr)6Si3 silicides precipitate as nanoparticles within and between the α / β phases, with an average particle size of 16 nm, but showing a tendency to be discontinuously distributed along grain boundaries. The component exhibits a tensile strength of 1380 MPa and an elongation of 10% at room temperature; and a tensile strength of 610 MPa and an elongation of 30% at 700 °C. No macroscopic cracks were found inside the component, but its high-temperature plasticity is significantly reduced. A comparison between Example 1 and this comparative example shows that the conventional solution aging treatment method promotes β grain coarsening and the distribution of some silicides along grain boundaries, resulting in a decrease in the high-temperature performance of the component compared to Example 1.

[0058] Comparative Example 3 Same as Example 1, except that the real-time monitoring unit and adaptive heating unit are not enabled in step S5, there is no interlayer temperature control, and only the initial preheating of the substrate is 500°C (the rest of the process and parameters remain unchanged).

[0059] The nano-reinforced high-temperature titanium alloy component prepared in this comparative example has a phase composition consisting of β grains, primary α phase, secondary α phase, and (Ti,Zr)6Si3 silicide particles. The β grains show significant coarsening, with an average particle size of 52 μm and an equiaxed grain ratio reduced to 40%. The average thickness of the primary α phase increases to 0.52 μm, while the secondary α phase coarsens to 180 nm and exhibits highly uneven distribution. The average particle size of the (Ti,Zr)6Si3 silicide particles increases to 68 nm, and a large number of coarse (Ti,Zr)6Si3 phase particles with an average size of approximately 170 nm are continuously distributed along the grain boundaries. The component exhibits a tensile strength of 1090 MPa and an elongation of 7% at room temperature; and a tensile strength of 490 MPa and an elongation of 21% at 700 °C. Microcracks were observed in localized areas within the component. Compared with Example 1, it can be seen that the lack of real-time monitoring and interlayer temperature control leads to coarsening of the microstructure, local segregation of silicides and concentration of thermal stress. The coupling effect of these three factors results in a significant decrease in the mechanical properties of the component.

[0060] Comparative Example 4 Same as Example 1, except that a fixed power mode is used in step S5, and the partitioned variable parameter energy input strategy is not performed (the rest of the process and parameters remain unchanged).

[0061] The nano-reinforced high-temperature titanium alloy component prepared in this comparative example has a phase composition consisting of β grains, primary α phase, secondary α phase, and (Ti,Zr)6Si3 silicide particles. The average particle size of the equiaxed β grains increased to approximately 40 μm, and the proportion of equiaxed grains decreased to approximately 55%, with a distinct mixed region of columnar and equiaxed grains. The average thickness of the primary α phase increased to 0.42 μm, and the secondary α phase coarsened to 140 nm. The average particle size of the (Ti,Zr)6Si3 silicide particles increased to 52 nm, and coarse (Ti,Zr)6Si3 phases, approximately 120 nm in size, were continuously distributed along the grain boundaries in high-stress risk areas such as the corners. The component exhibited a tensile strength of 1190 MPa and an elongation of 11% at room temperature; and a tensile strength of 570 MPa and an elongation of 30% at 700 °C. No macroscopic cracks were observed inside the component, but signs of microcrack initiation were observed in the corner regions. Compared with Example 1, it can be seen that by adopting a fixed power mode without partitioned variable parameter energy input, it is impossible to adjust the heat input and cooling rate according to the needs of different regions. This leads to the accumulation of thermal stress in high stress areas and the failure to break the solute enrichment layer in areas where silicides are prone to agglomeration. Consequently, the microstructure becomes coarse and uneven, silicide agglomeration intensifies, mechanical properties decrease significantly, and the risk of defects increases.

[0062] Comparative Example 5 Same as Example 1, except that the gradient transition layer and interface control process are not used in step S5: no “composition-performance transition layer” is introduced between the substrate and the component; no “micro-alloying pulse powder feeding” is introduced between the layers (the rest of the process and parameters remain unchanged).

[0063] The nano-reinforced high-temperature titanium alloy component prepared in this comparative example has a phase composition consisting of β grains, primary α phase, secondary α phase, and (Ti,Zr)6Si3 silicide particles. At the substrate / deposited layer interface, coarse columnar crystalline regions are formed, approximately 200 μm wide, with an average grain size of 62 μm. In the deposited layer further away from the interface, the average β grain size increases to 29 μm, and the proportion of equiaxed grains decreases to 60%. The average width and thickness of the primary α phase increase to 0.38 μm, and the secondary α phase coarsens to 120 nm. (Ti,Zr)6Si3 silicides are continuously distributed along grain boundaries near the interface and within the deposited layer, with an average grain size of approximately 100 nm. Micron-sized silicide clusters (average size approximately 0.65 μm) are observed in some areas, and microcracks are observed at the substrate / deposited layer interface and in the structural transition region. The component has a tensile strength of 1220 MPa and an elongation of 10% at room temperature; and a tensile strength of 550 MPa and an elongation of 27% at 700℃. Compared with Example 1, it can be seen that without the use of a gradient transition layer and interface control process, the thermal expansion mismatch stress between the substrate and the component cannot be alleviated. Furthermore, the special structural transition region lacks the grain refinement and pinning effect of rare earth microalloying, resulting in coarse microstructure, intensified silicide segregation, and decreased interfacial bonding strength, ultimately leading to a decline in mechanical properties.

[0064] Comparative Example 6 Same as Example 1, except that the chemical composition of the nano-reinforced high-temperature titanium alloy in step S1 is as follows by mass percentage: Al: 6.5%, Zr: 8.5%, Mo: 3.0%, Nb: 1%, Sn: 3.5%, Si: 0.35%, with the balance being Ti and unavoidable impurities.

[0065] The nano-reinforced high-temperature titanium alloy component prepared in this comparative example exhibits changes in phase composition and microstructure compared to Example 1: the average particle size of equiaxed β grains increases to 48 μm, and the proportion of equiaxed grains decreases significantly to 42%; the primary α phase is lamellarly, with an average thickness increasing to 0.50 μm, while the secondary α phase coarsens to 150 nm and its distribution uniformity decreases; the (Ti,Zr)6Si3 silicide shows decreased precipitation uniformity and an average particle size increasing to 60 nm due to the lack of Ta synergistic regulation, with slight segregation at grain boundaries and the α / β interface, and the formation of coarse silicide phases with a size of approximately 130 nm in local areas. This component exhibits a tensile strength of 1180 MPa and an elongation of 17% at room temperature; and a tensile strength of 500 MPa and an elongation of 35% at 700 °C. Compared with Example 1, omitting the Ta element weakens the synergistic grain refinement effect between Zr and Ta. Although the Mo content is increased to 3.0% to compensate for the β phase stabilization effect, it cannot replace the role of Ta in refining β grains, inhibiting columnar epitaxial growth, and promoting the uniform dispersion precipitation of silicide (Ti,Zr)6Si3. This leads to a decrease in microstructure uniformity, a weakening of the second phase dispersion strengthening effect, and ultimately a decrease in alloy strength and a deterioration in overall comprehensive mechanical properties.

[0066] 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 by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloy, characterized in that, Includes the following steps: Composition Design: The chemical composition of the nano-reinforced high-temperature titanium alloy, by mass percentage, is as follows: Al: 6.0~7.0%, Zr: 8.5~9.5%, Mo: 1.5~2.5%, Nb: 0.8~1.2%, Sn: 3.5~4.5%, Ta: 1.5~2.5%, Si: 0.25~0.45%, with the balance being Ti and unavoidable impurities; Raw material weighing: Weigh pure titanium raw materials, pure aluminum raw materials, pure tin raw materials, and intermediate alloy particles according to the composition design calculation; Smelting and casting: The raw materials are subjected to vacuum consumable arc layered gradient melting, casting and staged quenching to obtain high-temperature titanium alloy ingots; Powder preparation: The high-temperature titanium alloy ingot is atomized into high-temperature titanium alloy powder by plasma rotating electrode; Laser-directed energy deposition: using the high-temperature titanium alloy powder as raw material, laser-directed energy deposition is performed on the surface of a preheated substrate; during the laser-directed energy deposition process, heat-mass transfer is dynamically controlled by combining a partitioned scanning strategy, a partitioned variable parameter energy input strategy, a gradient transition layer and interface control strategy, and a multi-source sensor real-time monitoring and adaptive temperature field control strategy. Heat treatment: The formed part obtained by laser directional energy deposition is subjected to high temperature short-time aging treatment to obtain the nano-reinforced high temperature titanium alloy.

2. The method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloy as described in claim 1, characterized in that, The pure titanium raw material includes sponge titanium, the pure aluminum raw material includes aluminum granules, the pure tin raw material includes tin granules, and the intermediate alloy particles include Al-Ta intermediate alloy particles, Nb-30Si intermediate alloy particles, and Ti-30Mo-15Nb-5Zr intermediate alloy particles.

3. The method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloy as described in claim 2, characterized in that, The vacuum self-consuming arc layered gradient melting process includes: sequentially adding 35-40 wt% of sponge titanium, Ti-30Mo-15Nb-5Zr master alloy particles, 10-20 wt% of sponge titanium, Nb-30Si master alloy particles, and 10-20 wt% of sponge titanium to a vacuum self-consuming arc melting device; finally adding uniformly mixed aluminum granules, tin granules, Al-Ta master alloy particles, and the remaining sponge titanium; and evacuating the vacuum to a vacuum degree of 5×10⁻⁶. -3 Pa ~ 1×10 -2 After Pa, vacuum self-consuming arc melting is carried out at 1700~1750℃. After the raw materials are completely melted, they are kept at 1400~1500℃ for 2~4 hours. The step of graded quenching includes: first air cooling to 800°C, followed by immediate water quenching.

4. The method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloy as described in claim 1, characterized in that, The parameters for plasma rotating electrode atomization include: atomization voltage of 30~35kV, atomization current of 150~180A, rotation speed of 9000~12000r / min, and atomization chamber vacuum degree ≤1×10⁻⁶. -2 Pa.

5. The method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloy as described in claim 1, characterized in that, The preheating temperature is 450~550℃, and the time is 5~10min; The basic process parameters for laser-directed energy deposition include: laser power of 1800~2800W, scanning speed of 8~15mm / s, powder feed rate of 5~15g / min, spot diameter of 4mm, layer thickness of 0.5mm, and scanning spacing of 3mm. The partition scanning strategy includes: adopting a chessboard-style partition scanning strategy, rotating 67° between layers and delaying for 10 seconds.

6. The method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloy as described in claim 5, characterized in that, The partitioned variable parameter energy input strategy includes: in the high stress risk area, switching from the basic process parameters to a 1500W low power + 7mm / s slow scan mode; in the melt pool edge area where silicides are prone to segregation, switching from the basic process parameters to a 200~500Hz high frequency pulse energy input mode. The gradient transition layer and interface control strategy includes: before deposition, depositing 1 to 2 layers of low-melting-point, high-plasticity alloy transition layer on the substrate surface as a composition-performance transition layer; in the structural transition region, intermittently adding 0.1 to 0.3 wt% of rare earth elements by micro-alloy pulse powder feeding, once every 3 layers.

7. The method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloy as described in claim 5, characterized in that, The multi-source sensing real-time monitoring and adaptive temperature field control strategy includes: throughout the deposition process, through multi-source sensing real-time monitoring and adaptive temperature field control, the interlayer temperature is always maintained within 60% to 80% of the recrystallization temperature of the high-temperature titanium alloy; and the surface strain, the temperature field of the molten pool and its surroundings, and the internal thermal deformation of the substrate are collected in real time. When the strain mutation is greater than 0.5%, the cooling rate at the edge of the molten pool is greater than 80℃ / s, or the interlayer temperature difference is greater than 50℃, the deposition is paused, the induction heating device is activated to heat the risk area to 350 to 500℃, and the temperature of the deposited area is maintained at 350 to 500℃ by an infrared heat preservation cover. After confirming that the interlayer temperature difference is ≤30℃, the deposition continues.

8. The method for directional energy deposition additive manufacturing of nano-reinforced high-temperature titanium alloy as described in claim 7, characterized in that, The parameters for the high-temperature short-time aging treatment include: holding at 750℃ for 1~3 hours, followed by air cooling.

9. A nano-reinforced high-temperature titanium alloy prepared by a directional energy deposition additive manufacturing method according to any one of claims 1-8.

10. The application of the nano-reinforced high-temperature titanium alloy as described in claim 9 in the preparation of hot-end components for aerospace engines.

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