A method for preparing high-performance titanium-based composite materials resistant to 700℃ using selective laser melting technology.

Abstract

A method for preparing high-performance titanium-based composite materials resistant to 700℃ using selective laser melting (SLM) technology is disclosed. This invention relates to the field of alloys and aims to solve the problems of cumbersome and complex traditional methods for preparing and processing high-temperature titanium-based composite materials, the difficulty in forming complex components, and the challenge of balancing formability and high-temperature performance in 3D printing of titanium-based composite materials. The method uses TC11 titanium alloy powder as the matrix for preparing high-temperature titanium-based composite materials via SLM, and ceramic powder as the raw material for composition modification. The mixture is then mixed using low-energy ball milling and dried. A three-dimensional model is designed and constructed, and printing parameters and strategies are set. The printing substrate is preheated, and the dried composite powder is used for printing. Finally, annealing heat treatment is performed. The resulting lightweight titanium-based composite material achieves a heat resistance of 700℃, better meeting application requirements.

Description

Technical Field

[0001] This invention belongs to the field of alloys, and specifically relates to a method for preparing high-performance titanium-based composite materials resistant to 700℃ using selective laser melting technology. Background Technology

[0002] High-temperature titanium alloys are key structural materials in my country's aerospace field. Due to their low density, high specific strength, excellent high-temperature performance, and corrosion resistance, they are widely used and rapidly developed in the aerospace industry, often referred to as the backbone of aviation. Aircraft engines place stringent performance requirements on high-temperature titanium alloys, demanding a good balance of room-temperature performance, high-temperature strength, creep resistance, thermal stability, fatigue performance, and fracture toughness. However, the requirements for these performance indicators are contradictory to the material's composition and microstructure; for example, room-temperature toughness and high-temperature strength are often inversely related. Laser selective melting additive manufacturing technology can achieve near-net-shape forming of complex metal components, offering significant advantages in improving dimensional accuracy, manufacturing efficiency, and material utilization. Although many high-temperature titanium alloys are currently available, such as TA15, TC31, Ti55, Ti60, Ti65, and Ti600, which can operate at temperatures up to 500℃-600℃, they typically exhibit an inverse relationship between material thermal strength and laser selective melting (LSM) formability. For example, Ti60, a titanium alloy resistant to 600℃, is unsuitable for the extremely rapid cooling of LSMs, as it is prone to macroscopic cracking and poor formability. TA15 titanium alloy has good LSM formability, but its long-term operating temperature is only 500℃, which is insufficient to meet the temperature resistance requirements of thermal protection components for high-speed aircraft, necessitating improvements in its high-temperature mechanical properties.

[0003] With its unique advantages of no mold opening and full digitalization, rapid solidification speed and near-net-shape forming of complex parts, additive manufacturing technology is being demonstrated and applied more and more widely in the aerospace field for structural and functional parts, providing a highly promising new method for the preparation of metal matrix composites.

[0004] In the process of preparing high-temperature resistant titanium-based composite materials using selective laser melting (SLM) additive manufacturing technology, introducing a certain amount of reinforcing phase through powder mixing can refine grains, eliminate coarse columnar crystal texture, and thus improve the material's thermal strength and service temperature. However, it also increases the difficulty of forming the material. Because the melting and solidification process in additive manufacturing involves rapid temperature changes, uneven plastic deformation caused by thermal expansion and contraction or solid-state phase transformations easily occurs inside the sample, often resulting in significant residual stress and macroscopic cracking. Inappropriate printing parameters, such as energy density, can also easily lead to defects such as cracks or porosity. Ultimately, it becomes difficult to simultaneously achieve good formability and high-temperature performance in titanium-based composite materials, necessitating further heat treatment to stabilize the microstructure. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of cumbersome and complex traditional methods for preparing and processing high-temperature resistant titanium-based composite materials, the difficulty in forming complex components, and the difficulty in balancing formability and high-temperature performance of titanium-based composite materials in 3D printing. The invention provides a method for preparing high-performance titanium-based composite materials resistant to 700℃ by using selective laser melting technology.

[0006] Traditional methods for preparing high-temperature resistant titanium-based composite materials include melting and casting, and powder metallurgy. These methods involve cumbersome processing steps, long cycles, low material utilization, and significant difficulty in machining complex-shaped components. In contrast, the laser selective melting technology used in this invention offers strong comprehensive functionality, reduces assembly time, improves material utilization, and saves direct costs, thereby achieving near-net-shape forming of complex components with high efficiency and quality.

[0007] Currently, the heat resistance of high-temperature titanium alloys and high-temperature resistant titanium-based composites prepared by selective laser melting (SLM) is insufficient to meet the structural material requirements of high-precision fields such as aerospace. This invention addresses this issue by selecting TC11 alloy, which possesses both high thermal strength and formability, as the matrix. Through methods such as adding high-strength ceramic particles as reinforcement and designing their content, controlling ball milling parameters, designing the shape of the printing model, optimizing printing parameters, and annealing heat treatment, a high-temperature resistant titanium-based composite material with good formability is prepared. This results in a high-performance titanium-based composite material that can withstand 700℃, overcoming the previous bottleneck of 600℃.

[0008] To address the aforementioned needs, this invention proposes a titanium-based composite material that combines high-temperature resistance with excellent laser selective melting (LSM) formability. It utilizes α+β type mid-temperature titanium alloy TC11 powder as the matrix, with a nominal alloy composition of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si. Its service temperature can reach 500℃, and the high Mo content ensures the alloy's plasticity and LSM formability. Furthermore, the presence of Si inherently enhances the material's thermal strength. On this basis, TiB2 ceramic powder is further introduced, undergoing an in-situ synthesis reaction with Ti to generate TiB and other ceramic reinforcing phases. This strengthening effect further improves the high-temperature mechanical properties, achieving a heat resistance temperature of 700℃.

[0009] This invention selects medium-temperature titanium alloy TC11 as the matrix and high-modulus TiB and other ceramic whiskers as reinforcements. By optimizing the laser selective melting manufacturing parameters and subsequent heat treatment parameters, a lightweight titanium-based composite material with good formability, excellent high-temperature mechanical properties and high-temperature stability is prepared. The heat resistance temperature reaches 700℃, which better meets the application requirements.

[0010] The present invention has the following beneficial effects:

[0011] (1) This invention adds a TiB2 ceramic phase to TC11 alloy, which undergoes an in-situ synthesis reaction with Ti to generate a TiB reinforcing phase. This phase exhibits a unique network structure distribution where a hard phase surrounds a soft phase, thus improving strength. Further optimization of ball milling parameters and reinforcing phase content ultimately yields a TiBw / TC11 composite powder with an optimal TiB2 content of 0.6 wt.%. The printed composite material was tested and showed a room temperature tensile strength of 1627 MPa (e.g., ...). Figure 4 As shown), the room temperature tensile strength of the printed TC11 alloy under the same printing parameters is 1475 MPa, which is 10% higher than that of the printed alloy (as shown). Figure 3 (As shown).

[0012] (2) TiBw / TC11 composite materials are prone to macroscopic cracking during selective laser melting due to the extremely high cooling rate and temperature gradient, resulting in very poor formability. This invention combines multiple methods during selective laser melting to directly obtain components without macroscopic cracking and with low residual stress—that is, by controlling the substrate preheating temperature, optimizing process parameters, optimizing the structural design of the formed component, and subsequent annealing heat treatment, macroscopic cracking is effectively avoided, resulting in a high-temperature resistant titanium-based composite material with good formability and high density (such as…). Figure 1-2 (As shown).

[0013] (3) The composite material prepared by this invention, after annealing heat treatment, has a room temperature tensile strength ≥1200MPa and an elongation ≥10%; a tensile strength at 700℃ ≥450MPa; and creep performance: the duration under tensile stress of 200MPa at 700℃ is ≥2h. TC11 alloy and TiB / TA15 composite material were also prepared using the same process parameters. The tensile strength of TC11 alloy at 700℃ was 313MPa, an increase of 44%; the tensile strength of TiB / TA15 composite material at 700℃ was 342MPa, an increase of 32%. Attached Figure Description

[0014] Figure 1 Macroscopic cracking photographs of partially printed TiB / TC11 composite material before process optimization (block size: 45×15×15mm);

[0015] Figure 2 Macroscopic photographs of TiB / TC11 composite materials in the printed and heat-treated states after process optimization (block size: 45×15×15mm);

[0016] Figure 3 Room temperature tensile properties of TC11 alloy in printed state;

[0017] Figure 4 Room temperature tensile properties of printed TiB / TC11 composite material;

[0018] Figure 5 Graph of tensile properties of annealed TC11 alloy at 700℃;

[0019] Figure 6 Graph of tensile properties of annealed TiB / TA15 composite material at 700℃;

[0020] Figure 7 Room temperature tensile properties of annealed TiB / TC11 composite material;

[0021] Figure 8 Graph of tensile properties of annealed TiB / TC11 composite material at 700℃;

[0022] Figure 9 High-temperature creep curve of annealed TiB / TC11 composite material at 700℃ / 200MPa. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the spirit of the contents disclosed in the present invention will be described in detail below. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0024] The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0025] Example 1

[0026] This embodiment is performed according to the following steps:

[0027] (1) Select (α+β) dual-phase medium-temperature titanium alloy TC11 spherical powder as printing raw material. The nominal composition of the alloy is Ti-6.5Al-3.5Mo-1.5Zr-0.3Si, and the particle size distribution range is 15-53μm.

[0028] (2) Place the alloy powder in a vacuum drying oven, set the drying temperature to 120℃ and the drying time to 4h, thereby eliminating the static electricity of the powder after ball milling and making the powder fully dry, thus improving the powder flowability.

[0029] (3) Design and build a three-dimensional model, import it into the model processing software corresponding to the printer, and place the model in a suitable position as needed.

[0030] (4) The dried powder is manufactured by selective laser melting process. The forming process is carried out in an argon protective atmosphere. The forming process window is: laser power 185W, scanning power 1100mm / s, powder layer thickness 30μm, laser scanning spacing 90μm, and substrate preheating temperature 180℃.

[0031] (5) The TC11 alloy in the printed state was obtained by selective laser melting and then subjected to subsequent annealing heat treatment to control the variables. The temperature was set to 900℃ and the holding time was set to 2h. After annealing, the furnace was cooled to room temperature.

[0032] In this embodiment, the room temperature mechanical properties of the printed TC11 alloy are as follows: tensile strength is 1475 MPa (e.g., Figure 3 (As shown); High-temperature mechanical properties of annealed TC11 alloy: Tensile strength reaches 313.27 MPa at 700℃, and elongation is 23.69% (as shown). Figure 5 (As shown).

[0033] Example 2

[0034] This embodiment is performed according to the following steps:

[0035] (1) Near-α titanium alloy TA15 was selected as the matrix with a particle size distribution range of 15-53μm. Its heat resistance temperature (500-550℃) is relatively high and its high temperature performance is good. Titanium diboride (chemical formula TiB2) powder was selected as the raw material for composition modification with a particle size of 0.5μm.

[0036] (2) Mix spherical TA15 titanium alloy powder and TiB2 powder raw materials in a certain proportion. After mixing, the mass fraction of TiB2 powder accounts for 0.5 wt.% of the mass fraction of the mixed powder. The mixed powder is ball-milled under argon protection with a ball-to-material ratio of 2:1, a ball milling speed of 220 r / min, and a ball milling time of 5 h.

[0037] (3) Place the ball-milled powder in a vacuum drying oven, set the drying temperature to 120℃ and the drying time to 4h, thereby eliminating the static electricity of the ball-milled powder and making the powder fully dry and improving the powder flowability.

[0038] (4) Design and build a three-dimensional model, add chamfers and other structural designs to prevent the sample from cracking, and then import it into the corresponding model processing software of the printer and place the model in a suitable position as needed.

[0039] (5) The dried powder is manufactured by selective laser melting process. The forming process is carried out in an argon protective atmosphere. The forming process window is: laser power 180W, scanning power 1100mm / s, powder layer thickness 30μm, laser scanning spacing 90μm, and substrate preheating temperature 180℃.

[0040] (6) 0.5wt.% TiB / TA15 titanium-based composite material was obtained by selective laser melting. Subsequent annealing heat treatment was carried out to eliminate residual stress. The temperature was set to 900℃ and the holding time was set to 2h. After annealing, the furnace was cooled to room temperature.

[0041] In this embodiment, the annealed TiB / TA15 titanium-based composite material was tested and its high-temperature mechanical properties were obtained: tensile strength at 700℃ was 342 MPa, and elongation was 32% (e.g., Figure 6 (As shown).

[0042] Example 3

[0043] This embodiment is performed according to the following steps:

[0044] (1) The (α+β) dual-phase medium-temperature titanium alloy TC11 spherical powder was selected as the matrix. The nominal composition of the alloy was Ti-6.5Al-3.5Mo-1.5Zr-0.3Si, and the particle size distribution range was 15-53μm. Titanium diboride (chemical formula TiB2) powder was selected as the raw material for composition modification, with a particle size of 0.5μm.

[0045] (2) Spherical TC11 titanium alloy powder and TiB2 powder raw materials were mixed in a certain proportion. After mixing, the mass fraction of TiB2 powder accounted for 0.6 wt.% of the mass fraction of the mixed powder. The mixed powder was ball-milled under argon protection with a ball-to-material ratio of 2:1, a ball milling speed of 200 r / min, and a ball milling time of 5 h.

[0046] (3) Place the ball-milled powder in a vacuum drying oven, set the drying temperature to 120℃ and the drying time to 4h, thereby eliminating the static electricity of the ball-milled powder and making the powder fully dry and improving the powder flowability.

[0047] (4) Design and build a three-dimensional model, add chamfers and other structural designs to prevent the sample from cracking, and then import it into the corresponding model processing software of the printer and place the model in a suitable position as needed.

[0048] (5) The dried powder is manufactured by selective laser melting process. The forming process is carried out in an argon protective atmosphere. The forming process window is: laser power 185W, scanning power 1100mm / s, powder layer thickness 30μm, laser scanning spacing 90μm, and substrate preheating temperature 180℃.

[0049] (6) 0.6wt.% TiB / TC11 titanium-based composite material was obtained by selective laser melting. Subsequent annealing heat treatment was carried out to eliminate residual stress. The temperature was set to 900℃ and the holding time was set to 2h. After annealing, the furnace was cooled to room temperature.

[0050] The room temperature mechanical properties of the 0.6 wt.% TiB / TC11 titanium-based composite material in this embodiment are as follows: tensile strength 1627 MPa, elongation 0.62% (e.g. Figure 4(As shown). The annealed TiB / TC11 titanium-based composite material was tested and its room temperature mechanical properties were obtained as follows: tensile strength 1213.53 MPa, elongation 10% (as shown). Figure 7 (As shown); High-temperature mechanical properties: Tensile strength reaches 452.34 MPa at 700℃, and elongation is 13.53% (as shown). Figure 8 (As shown); the duration of saturation at 700℃ and 200MPa is 2.2h (as shown). Figure 9 (As shown). The results show that the in-situ self-generated TiB / TC11 titanium-based composite material prepared by low-energy ball milling of TiB2 ceramic powder and TC11 titanium alloy and then laser selective melting technology has improved room temperature and high temperature tensile properties, effectively increasing the heat resistance temperature of the material to 700℃, while also ensuring good laser selective melting formability, enabling near-net-shape forming of complex and precision components.

Claims

1. A method for manufacturing a 700℃-resistant high-performance titanium-based composite material by using a laser selective melting technique, characterized in that The method is carried out in the following manner: (1) using titanium alloy TC11 powder as the base material for laser selective melting to prepare a high-temperature titanium-based composite material, and using ceramic powder as the component-modified raw material; the titanium alloy TC11 is an alpha+beta dual-phase medium-temperature titanium alloy TC11; the ceramic powder is titanium diboride; the particle size of the ceramic powder is 0.5-3.0 μm; (2) mixing the titanium alloy TC11 powder and the ceramic powder under an argon atmosphere by low-energy ball milling to obtain a composite powder; (3) placing the composite powder in a vacuum drying box for sufficient drying; (4) designing and constructing a three-dimensional model, setting the printing parameters and printing strategy, preheating the printing substrate, and printing the dried composite powder in an argon protective atmosphere; the printing parameters are as follows: laser power 150-250 W, scanning speed 900 mm / s-1200 mm / s, powder layer thickness 30-50 μm, laser scanning pitch 80-100 μm, and substrate preheating temperature 100-200 ℃; (5) removing the printed titanium-based composite material for annealing heat treatment; the annealing heat treatment temperature range is 800-1000 ℃, and the heat treatment time range is 1-4 h; after annealing, the furnace is cooled to room temperature, and the process is completed.

2. The method for preparing high-performance titanium-based composite materials resistant to 700℃ by using selective laser melting technology according to claim 1, characterized in that The titanium alloy TC11 powder is near-regular spherical, and the particle size is 15-53 μm.

3. The method for preparing high-performance titanium matrix composite materials resistant to 700℃ by using selective laser melting technology according to claim 1, characterized in that The ceramic powder accounts for 0.1-5.0 wt.% of the composite powder.

4. The method for preparing high-performance titanium matrix composite materials resistant to 700℃ by using selective laser melting technology according to claim 1, characterized in that In step (2), the low-energy ball milling parameters are as follows: rotation speed 180-220 r / min, time 4-6 h, and ball-to-material ratio (2-3):

1.

5. The method of claim 1, wherein the method of manufacturing a high performance titanium matrix composite material resistant to 700°C by using a selective laser melting technique is characterized by In step (3), the drying temperature of the vacuum drying box is 80-120 ℃, and the drying time is 1-4 h.

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