3D printing titanium alloy and preparation method thereof

Abstract

The invention belongs to the technical field of alloys, and particularly relates to a 3D printing titanium alloy and a preparation method thereof. The invention particularly provides a preparation method of a TA15 titanium alloy for selective laser melting printing. The structure uniformity and the mechanical property of a material can be remarkably improved. By optimizing SLM printing process parameters (including laser power, scanning speed, filling spacing and layer thickness), the heat accumulation effect and cooling rate in the forming process are effectively controlled, so that a microstructure with high density, uniform structure and refined grains is obtained, and the hardness, strength and toughness of the titanium alloy are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloys, and in particular relates to a 3D printing titanium alloy and a preparation method thereof. Background Art

[0002] Titanium alloys have become an indispensable key material in the field of high-end manufacturing due to their excellent properties, including high specific strength, good corrosion resistance, and biocompatibility. Among them, TA15 titanium alloy, as a typical α+β type titanium alloy, is widely used in the manufacture of load-bearing structural parts in the aerospace field. Traditional TA15 titanium alloy processing technologies mainly include forging and casting, but these methods often have problems such as complex processes, serious material waste, and long processing cycles when manufacturing parts with complex shapes. 3D printing technology breaks the limitations of traditional manufacturing processes. It can directly melt and solidify metal powder layer by layer based on computer-aided design (CAD) models, achieving near-net shape of complex structure TA15 titanium alloy parts. In high-end fields such as aerospace and biomedicine, the demand for titanium alloy components with complex internal structures and high performance requirements is growing.

[0003] The unique rapid melting and solidification process of SLM results in a microstructure in TA15 titanium alloy that is distinct from that produced by conventional machining methods. This microstructure features fine grains and directional growth. However, the significant temperature gradients during SLM can generate high residual stresses within the material, leading to poor toughness and cracking—common defects in SLM. Therefore, studying the effects of process parameters such as laser power and scanning speed on microstructure and mechanical properties is crucial for advancing laser melting and forming technologies. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a high-strength and high-toughness 3D printed titanium alloy and a preparation method thereof to solve the problems existing in the above-mentioned prior art. The present invention can obtain a stable and homogeneous organizational structure by regulating the 3D printing parameters and heat treatment process parameters, thereby improving its hardness, strength and toughness.

[0005] It is important to note that studying the impact of process parameters on microstructure can provide a deeper understanding of phenomena during the SLM process, such as the solidification behavior of the melt pool and the formation of the heat-affected zone. This not only helps to improve theoretical understanding of SLM technology but also provides a basis for precisely controlling microstructure through optimizing process parameters, thereby obtaining microstructure properties that meet the requirements of different application scenarios.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The first technical purpose of the present invention is to provide a method for preparing a 3D printed titanium alloy, the method specifically comprising the following steps:

[0008] 1) Raw material preparation

[0009] TA15 titanium alloy powder is selected, and the composition (mass percentage) is: Al 6.0-7.5%, Mo 1.5-2.5%, V0.5-1.5%, Fe≤0.3%, Si≤0.2%, and the rest is Ti; the powder preparation method preferably adopts gas atomization (GA) to prepare spherical powder, the particle size range is 15-53 μm, the particle size distribution is uniform, the powder morphology is spherical, and there is no obvious satellite powder, hollow powder and sticky powder.

[0010] 2) Powder pretreatment

[0011] TA15 titanium alloy powder is placed in a drying oven at 100°C for 3 hours to remove moisture adsorbed on the powder surface. After drying, it is cooled to room temperature under the protection of an inert gas (such as argon) and then loaded into the feed barrel of the SLM equipment to prevent oxidation.

[0012] 3) Selective laser melting printing process

[0013] The substrate was sandblasted to remove surface impurities such as oil, dust, and oxide film. It was then wiped dry with alcohol and mounted and leveled. Printing was performed under an inert atmosphere (Ar). The system oxygen content was controlled below 1000 ppm to prevent oxidation of the titanium alloy during the 3D printing process. The print platform preheated to a temperature of 50°C-100°C for 30 minutes to reduce thermal stress and warping risks. The printing parameters were set as follows: laser power of 200-280W, scan speed of 1000-1400mm / s, infill spacing of 65-105μm, layer height of 30μm, and scanning strategy: rotary scanning with an inter-layer rotation angle of 67°. Layer-by-layer stacking ultimately resulted in a metal block measuring 30*15*12mm.

[0014] 4) Post-printing processing

[0015] After printing is complete, the component is removed and cooled to room temperature under inert gas. Separate the component from the substrate using methods such as wire EDM. De-powdering is then performed on the component, including airflow cleaning, ultrasonic cleaning, or vacuum extraction.

[0016] Preferably, in step (3), the laser power is 240-280 W, the scanning speed is 1000-1200 mm / s, and the filling spacing is 75-85 μm.

[0017] The second technical purpose of the present invention is to provide a 3D printing titanium alloy, which is prepared by the above method.

[0018] Moreover, the 3D printed titanium alloy is a high-strength and high-toughness TA15 titanium alloy. The quasi-static tensile strength of the alloy reaches 1247 MPa and the total elongation at break reaches 10%.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The selective laser melting (SLM) printing method for preparing TA15 titanium alloy, provided by this invention, significantly improves the material's microstructure uniformity and mechanical properties. By optimizing SLM printing process parameters (including laser power, scanning speed, and fill spacing), the heat accumulation effect and cooling rate during the forming process are effectively controlled, resulting in a microstructure with high density, uniform structure, and refined grains.

[0021] Compared with traditional forging or casting processes, the TA15 titanium alloy components prepared by the present invention exhibit the following technical effects:

[0022] 1. Improved density: The component density reaches over 99.5%, effectively reducing porosity and increasing fatigue life;

[0023] 2. Optimized microstructure: The microstructure is mainly composed of fine α phase or needle-shaped α′ martensite, with significantly refined grain size, uniform structure, and avoidance of macrosegregation;

[0024] 3. Improved mechanical properties: Without heat treatment, the printed components can exhibit excellent mechanical properties, with a tensile strength of over 1200 MPa and an elongation at break of up to 10%;

[0025] 4. Anisotropy improvement: The inter-layer rotation scanning strategy effectively reduces the anisotropy of the printed components, improving the overall mechanical consistency and service reliability.

[0026] In summary, the present invention not only improves the comprehensive performance of TA15 titanium alloy components, but also ensures high-precision and high-repeatability additive manufacturing quality, providing a new technical path for the precision manufacturing of high-performance titanium alloy structural parts, and has good engineering application prospects and industrialization value. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0028] Figure 1 The SEM images of the powder particles in Examples 1 and 2;

[0029] Figure 2 Print the engineering stress-strain curves of titanium alloy for the two parameters in Examples 1 and 2;

[0030] Figure 3 EBSD IPF map of TA15 titanium alloy in Example 1;

[0031] Figure 4 This is the IPF map of the EBSD of TA15 titanium alloy in Example 2. DETAILED DESCRIPTION

[0032] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all 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.

[0033] The term "embodiment" is used herein specifically to describe any embodiment as "exemplary," and should not be construed as superior or preferable to other embodiments. Performance indicators in the embodiments of this application were tested using conventional testing methods in the art, unless otherwise specified. It should be understood that the terms used in this application are intended solely to describe specific implementations and are not intended to limit the disclosure herein.

[0034] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0035] In order to better illustrate the content of this application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that this application can be implemented without certain specific details. In the examples, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of this application.

[0036] Under the premise of no conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of this application.

[0037] The invention discloses a preparation method of a 3D printing titanium alloy.

[0038] For a better understanding of the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as limiting the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above invention content are also considered to fall within the scope of protection of the present invention.

[0039] Example 1:

[0040] 1. Raw material preparation

[0041] TA15 titanium alloy powder is selected, and the composition (mass percentage) is: Al 6.0-7.5%, Mo 1.5-2.5%, V0.5-1.5%, Fe≤0.3%, Si≤0.2%, and the rest is Ti; the powder preparation method preferably adopts gas atomization (GA) to prepare spherical powder, the particle size range is 15-53 μm, the particle size distribution is uniform, the powder morphology is spherical, and there is no obvious satellite powder, hollow powder and sticky powder.

[0042] 2. Powder pretreatment

[0043] TA15 titanium alloy powder is placed in a drying oven at 100°C for 3 hours to remove moisture adsorbed on the powder surface. After drying, it is cooled to room temperature under the protection of an inert gas (such as argon) and then loaded into the feed barrel of the SLM equipment to prevent oxidation.

[0044] 3. Selective laser melting printing process

[0045] The substrate was sandblasted to remove surface impurities such as oil, dust, and oxide film. It was then wiped dry with alcohol and leveled before being mounted. Printing was performed under an inert atmosphere (Ar). The system oxygen content was controlled below 1000ppm to prevent oxidation of the titanium alloy during the 3D printing process. The print platform was preheated to 50°C for 30 minutes to reduce thermal stress and warping risks. The printing parameters were set as follows: laser power of 280W, scan speed of 1000mm / s, infill spacing of 85μm, layer height of 30μm, and scanning strategy: rotary scanning with an inter-layer rotation angle of 67°. Layer-by-layer stacking ultimately resulted in a metal block measuring 30*15*12mm.

[0046] 4. Post-printing processing

[0047] After printing is complete, the component is removed and cooled to room temperature under inert gas. Separate the component from the substrate using methods such as wire EDM. De-powdering is then performed on the component, including airflow cleaning, ultrasonic cleaning, or vacuum extraction.

[0048] The final product is a high-strength and high-toughness TA15 titanium alloy with a quasi-static tensile strength of 1225 MPa and a total elongation at break of up to 9.35%.

[0049] Example 2:

[0050] 1. Raw material preparation

[0051] TA15 titanium alloy powder is selected, and the composition (mass percentage) is: Al 6.0-7.5%, Mo 1.5-2.5%, V0.5-1.5%, Fe≤0.3%, Si≤0.2%, and the rest is Ti; the powder preparation method preferably adopts gas atomization (GA) to prepare spherical powder, the particle size range is 15-53 μm, the particle size distribution is uniform, the powder morphology is spherical, and there is no obvious satellite powder, hollow powder and sticky powder.

[0052] 2. Powder pretreatment

[0053] TA15 titanium alloy powder is placed in a drying oven at 100°C for 3 hours to remove moisture adsorbed on the powder surface. After drying, it is cooled to room temperature under the protection of an inert gas (such as argon) and then loaded into the feed barrel of the SLM equipment to prevent oxidation.

[0054] 3. Selective laser melting printing process

[0055] The substrate was sandblasted to remove surface impurities such as oil, dust, and oxide film. It was then wiped dry with alcohol and mounted and leveled. Printing was performed under an inert atmosphere (Ar). The system oxygen content was controlled below 1000 ppm to prevent oxidation of the titanium alloy during the 3D printing process. The print platform was preheated to 50°C for 30 minutes to reduce thermal stress and warping risks. The printing parameters were set as follows: laser power of 240 W, scan speed of 1000 mm / s, infill spacing of 75 μm, layer height of 30 μm, and scanning strategy: rotary scanning with an inter-layer rotation angle of 67°. The print platform was preheated to 100°C for 30 minutes to reduce thermal stress and warping risks. Layer-by-layer stacking ultimately resulted in a metal block measuring 30 x 15 x 12 mm.

[0056] 4. Post-printing processing

[0057] After printing is complete, the component is removed and cooled to room temperature under inert gas. Separate the component from the substrate using methods such as wire EDM. De-powdering is then performed on the component, including airflow cleaning, ultrasonic cleaning, or vacuum extraction.

[0058] The final product is a high-strength and high-toughness TA15 titanium alloy with a quasi-static tensile strength of 1247 MPa and a total elongation at break of up to 10%.

[0059] In summary, the present invention improves the microstructure and mechanical properties of the alloy by adjusting the selective laser melting parameters, making the alloy structure more uniform and improving its hardness, strength and toughness; the quasi-static tensile strength of the high-strength and high-toughness TA15 titanium alloy of the present invention can reach 1247 MPa, and the total elongation at break can reach 10%.

[0060] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a 3D printed titanium alloy, characterized in that: The method specifically includes the following: 1) Raw material preparation TA15 titanium alloy powder was selected, with a particle size range of 15 to 53 μm, uniform particle size distribution, and spherical powder morphology without obvious satellite powder, hollow powder, and sticky powder; 2) Powder pretreatment The TA15 titanium alloy powder was dried, then cooled to room temperature under inert gas protection and loaded into the feed barrel of the SLM equipment to avoid oxidation; 3) Selective laser melting printing process After sandblasting the substrate and wiping it dry with alcohol, it was installed and leveled. Printing was performed under inert atmosphere protection. A metal block with a size of 30*15*12mm was finally obtained by layer-by-layer stacking. 4) Post-printing processing After printing is completed, the component is taken out, cooled to room temperature under inert gas, separated from the substrate, and the component is de-powdered.

2. The method for preparing a 3D printing titanium alloy according to claim 1, wherein: TA15 titanium alloy powder composition, in mass percentage, includes: Al 6.0~7.5%, Mo 1.5~2.5%, V 0.5~1.5%, Fe≤0.3%, Si≤0.2%, and the rest is Ti.

3. The method for preparing a 3D printing titanium alloy according to claim 1, wherein: The drying temperature in step 2) is 100° C. and the drying time is 3 hours.

4. The method for preparing a 3D printing titanium alloy according to claim 1, wherein: In step 3), the oxygen content of the system is controlled below 1000 ppm, the preheating temperature of the printing platform is controlled at 50° C.-100° C., and the holding time is 30 minutes.

5. The method for preparing a 3D printing titanium alloy according to claim 1 or 4, characterized in that: The parameters during the printing process were set as follows: laser power of 200–280 W, scanning speed of 1000–1400 mm / s, filling spacing of 65–105 μm, layer height of 30 μm, scanning strategy: rotation scanning, and inter-layer rotation angle of 67°.

6. The method for preparing a 3D printing titanium alloy according to claim 1, wherein: The de-powdering treatment includes airflow cleaning, ultrasonic cleaning or vacuum powder extraction.

7. A 3D printed titanium alloy, characterized in that: The alloy is prepared by the method according to claim 1.

8. The 3D printing titanium alloy according to claim 7, characterized in that: The 3D printed titanium alloy is a high-strength and high-toughness TA15 titanium alloy. The quasi-static tensile strength of the alloy reaches 1247 MPa and the total elongation at break reaches 10%.

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