3d printing method for low cost ta15 parts based on bimodal particle size distribution near-spherical powder

Abstract

The application provides a 3D printing method for preparing a low-cost TA15 part based on a bimodal particle size distribution near-spherical powder and a high-performance low-cost TA15 part. The 3D printing method uses a bimodal particle size distribution near-spherical TA15 alloy powder with good uniformity as a raw material, improves the near-spherical powder bed density through bimodal grading of coarse powder and fine powder, and then prepares a low-cost high-performance TA15 part through an optimized selective laser melting (SLM) process parameter window suitable for bimodal distribution powder, thereby providing a more cost-effective preparation method for TA15 titanium alloy parts in aerospace.

Description

A 3D printing method for preparing low-cost TA15 parts based on near-spherical powder with bimodal particle size distribution. Technical Field

[0001] This invention relates to the field of metal material preparation technology, specifically to a 3D printing method for preparing low-cost TA15 parts based on near-spherical powder with bimodal particle size distribution. Background Technology

[0002] TA15 (Ti-6Al-2Zr-1Mo-1V) alloy, a high-aluminum-equivalent near-α-titanium alloy, is widely used in the aerospace field, especially for complex structural components in aircraft, missiles, launch vehicles, and satellites. However, due to its high melting point, high activity, and low thermal conductivity, traditional processes such as forging and casting present difficulties in forming complex structures. Selective laser melting (SLM), a commonly used metal additive manufacturing technology, uses a high-power laser beam to scan and melt pre-laid metal powder, thus depositing it layer by layer to form the desired part. It exhibits unique advantages in the high-precision fabrication of complex structural parts. Therefore, using SLM technology to manufacture complex TA15 structural parts is an extremely efficient method.

[0003] Currently, the raw materials used in SLM TA15 alloy production are mainly atomized spherical titanium powder. However, the low yield and high price of spherical powder significantly increase manufacturing costs. In recent years, to further reduce the cost of TA15 raw material powder, the research and industrial communities have successively developed near-spherical powder with simple preparation processes and low prices. However, the performance of parts formed based on near-spherical powder still falls short of the performance requirements of high-end equipment. As a raw material for SLM technology, the characteristics of powder, such as loose packing density and particle size, can alter the powder bed density and molten pool thermal fluid behavior during the forming process, thus significantly affecting the performance and quality of the formed parts. Therefore, adjusting the characteristics of low-cost near-spherical TA15 raw material powder to improve the quality and performance of formed parts is of great significance for its further application in the aerospace field. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the main objective of this invention is to provide a 3D printing method for preparing TA15 parts based on near-spherical powder with bimodal particle size distribution, and to produce high-performance, low-cost TA15 parts. This 3D printing method uses near-spherical TA15 powder with good uniformity as the raw material. The loose density of the near-spherical powder bed is improved by the bimodal gradation of coarse and fine powders, and a suitable process parameter window for near-spherical powder is optimized. Then, selective laser melting (SLM) technology is used to prepare high-performance, low-cost TA15 parts, providing a more cost-effective preparation method for precision TA15 titanium alloy parts in aerospace applications.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a 3D printing method for preparing low-cost TA15 parts based on near-spherical powder with a bimodal particle size distribution is provided.

[0006] The 3D printing method for preparing low-cost TA15 parts based on near-spherical powder with bimodal particle size distribution includes the following steps:

[0007] A three-dimensional model is drawn based on the shape of the part and then sliced ​​into layers. The obtained two-dimensional data information is then input into the SLM forming equipment.

[0008] Using bimodal TA15 near-spherical powder with a particle size distribution as the raw material and a forged TA15 plate as the substrate, TA15 parts of a specific shape are produced by SLM printing; wherein the bimodal TA15 near-spherical powder with a particle size distribution is prepared by using two types of TA15 near-spherical powder with different average particle sizes.

[0009] Furthermore, the two TA15 powders with different average particle sizes are referred to as fine powder and coarse powder, respectively. The fine powder has a particle size ≤20μm, and the coarse powder has a particle size of 20-70μm, excluding the endpoint value of 20μm.

[0010] Furthermore, the ratio of the medium particle size of the fine powder to the coarse powder is 0.414:1 to 0.175:1.

[0011] Preferably, the mass ratio of the fine powder to the coarse powder is 1:9 to 4:6.

[0012] Furthermore, the bimodal particle size distribution TA15 near-spherical powder has a particle size ≤70μm, a flowability <45s / 50g, and a loose packing density of 2.36~2.44g / cm³. 3 .

[0013] Furthermore, the SLM printing process parameters are: laser power of 180–220W, scanning speed of 900–1400 mm / s, scanning spacing of 0.1–0.15 mm, and powder layer thickness of 30–35 μm;

[0014] Preferably, the substrate preheating temperature is 200–400°C.

[0015] The process parameters described above in this invention are optimized based on orthogonal experiments. The process parameter window is obtained by comparing the density and mechanical properties of TA15 parts prepared under multiple sets of different 3D printing process parameters. Using this process window is more suitable for 3D printing of bimodal gradation near-spherical powders, thereby producing low-cost, high-performance titanium alloy parts.

[0016] Furthermore, the preparation of the bimodal near-spherical TA15 powder includes:

[0017] Two types of near-spherical TA15 powders with different average particle sizes were placed in a suspension and stirred for a certain period of time to prepare a powder mixture slurry.

[0018] Under a protective atmosphere, the powder mixture slurry is degreased to obtain the near-spherical TA15 powder with a bimodal particle size distribution.

[0019] Furthermore, the suspension is a mixture of polyethylene glycol 4000 and anhydrous ethanol, or a mixture of polyethylene glycol 4000 and deionized water.

[0020] Preferably, the mass of the polyethylene glycol 4000 is 0.5% to 2% of the total mass of the two TA15 near-spherical powders with different average particle sizes;

[0021] Preferably, the sum of the masses of the two near-spherical TA15 powders with different average particle sizes is 60-80% of the total mass of the powder mixture slurry.

[0022] Furthermore, the stirring speed is 200-500 r / min, and the stirring time is 2-8 h;

[0023] Preferably, the stirring is carried out under a high-purity argon protective atmosphere.

[0024] Furthermore, the degreasing treatment temperature is 100-150℃, the heating rate is 1-3℃ / min, and the degreasing time is 1-2h;

[0025] Preferably, the protective gas is high-purity argon.

[0026] To achieve the above objectives, according to a second aspect of the present invention, a high-performance, low-cost TA15 component is provided.

[0027] The high-performance, low-cost TA15 part is prepared using the 3D printing method described above; wherein, the TA15 part has a density ≥99.34%, a surface roughness ≤3.5Ra, a tensile strength of 1020.2~1083.8MPa, and an elongation of 12.3~15.2%.

[0028] This invention improves powder bed density through powder particle size distribution, thereby influencing the physical behavior of the molten pool dynamics during printing, ultimately achieving low-cost fabrication of high-performance TA15 parts. Specifically, it uses near-spherical TA15 powder with a bimodal particle size distribution as the raw material and prepares high-performance, low-cost TA15 parts through selective laser melting technology.

[0029] The preparation method of this invention has the following advantages:

[0030] 1) When the loose packing density of the powder is low, i.e., the interparticle gaps are large, laser energy is difficult to penetrate into the powder layer, resulting in a significant increase in the temperature gradient between the upper and lower surfaces of the powder layer. This leads to incomplete melting of the lower powder particles and poor interlayer bonding, thereby reducing the density of the formed part. This effect is even more pronounced for near-spherical powders due to their low sphericity. Compared to powders with a single-peak particle size distribution, the bi-peak particle size distribution powder used in this invention has a higher loose packing density and a deeper laser penetration depth, improving the aforementioned accumulation effect of laser energy on the powder surface. This significantly improves the density of the finished product, which is also closely related to mechanical properties such as tensile strength and elongation, thus also being improved.

[0031] 2) The near-spherical powder used in this invention has better adaptability to bimodal gradation compared to spherical powder. Due to its special geometric characteristics, near-spherical powder has a larger contact area between different powder particles in the powder bed. Using bimodal gradation more effectively increases the powder bed packing density, improves the laser absorption rate during the printing process, reduces defects in the printed parts, and improves the quality of the parts.

[0032] 3) The powder particle size distribution method in this invention expands the particle size range of powders used for 3D printing (single-peak powder 15-53μm, bi-peak powder ≤70μm), improves the utilization rate of fine powder with a particle size <15μm and coarse powder with a particle size >53μm, and can further reduce the cost of raw material powder.

[0033] 4) The selective laser melting technology used can accurately control the macroscopic structure and internal microscopic topology of the parts. It is an important process for the preparation of complex structural parts that integrate high precision and high performance. The optimized process parameter window is more suitable for near-spherical bimodal particle size distribution powder. The density, tensile strength and elongation of the finished parts are improved compared with the unoptimized spherical powder process parameters, which is more conducive to the preparation of low-cost high-performance 3D printed parts.

[0034] 5) Compared with conventional gas atomization and rotating electrode atomization of spherical titanium powder, the near-spherical TA15 powder preparation process used in this invention is simple, has a high powder yield, and low cost, which can effectively reduce the production cost of 3D printed titanium alloy parts.

[0035] 6) Traditional ball milling processes for preparing bimodal particle size distribution powders are prone to poor powder flowability and uneven density of formed parts due to uneven mixing. Furthermore, prolonged ball milling can introduce metallic elements and impurities such as oxygen and carbon from the grinding balls. Compared to ball milling, the bimodal particle size distribution powder prepared by the PEG4000 suspension wet mixing combined with furnace rotary degreasing technology proposed in this invention exhibits more uniform mixing of the two powders with different particle sizes. Moreover, the absence of grinding balls in the mixing process significantly reduces the introduction of impurities, thus facilitating the production of stable 3D printed titanium alloy parts. Attached Figure Description

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0037] Figure 1 is a morphology diagram of the near-spherical bimodal particle size distribution TA15 alloy powder prepared in Example 1 of the present invention. Detailed Implementation

[0038] Exemplary embodiments of this disclosure will now be described in more detail. It should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0039] According to a specific embodiment of the present invention, a 3D printing method for preparing high-performance, low-cost TA15 parts based on near-spherical powder with bimodal particle size distribution is provided.

[0040] The 3D printing method for preparing low-cost TA15 parts based on bimodal particle size distribution powder in this invention includes the following steps:

[0041] 1) Use UG software to draw a 3D model according to the required part shape and export the file.

[0042] 2) The 3D model is sliced ​​using Magics software, and the resulting 2D data and optimized process parameters are input into the SLM forming equipment. The laser power is 180–220W, the scanning speed is 900–1400 mm / s, the scanning spacing is 0.1–0.15 mm, the powder layer thickness is 30–35 μm, and the substrate preheating temperature is 200–400℃.

[0043] In the embodiments of the present invention, the specific process parameters are based on orthogonal experiments. The optimal process parameter window is obtained by comparing the density and mechanical properties of TA15 parts prepared under multiple sets of different 3D printing process parameters. Using this process window is more suitable for 3D printing of bimodal gradation near-spherical powder, thereby producing low-cost, high-performance titanium alloy parts.

[0044] It should be noted that the specific process parameters mentioned above should not limit the 3D printing method of powder bimodal gradation of the present invention. In practice, parameters such as substrate preheating temperature, laser power, scanning speed, and scanning spacing can be appropriately adjusted, and these adjustments should also be within the scope of protection of the present invention.

[0045] 3) Using bimodal TA15 powder as raw material and forged TA15 plate as substrate, TA15 parts of a specified shape are produced by SLM printing.

[0046] In the embodiments of the present invention, the bimodal particle size distribution TA15 powder has a particle size ≤70μm, a flowability <45s / 50g, and a loose packing density of 2.36~2.44g / cm³. 3 .

[0047] It is worth mentioning that after obtaining the bimodal particle size distribution TA15 powder, it needs to be vacuum-sealed. Before vacuum sealing, a small amount of powder can be taken for relevant tests. Specifically, the morphology, particle size distribution, flowability, and loose density of the mixed powder are observed by scanning electron microscopy, laser particle size analyzer, and Hall flow meter (funnel diameter of 5 mm).

[0048] In an embodiment of the present invention, the bimodal particle size distribution TA15 powder is a near-spherical powder.

[0049] In an embodiment of the present invention, the bimodal particle size distribution TA15 powder is prepared by using two TA15 powders with different average particle sizes, wherein the two TA15 powders with different average particle sizes are referred to as fine powder and coarse powder, respectively. The particle size of the fine powder is ≤20μm, and the particle size of the coarse powder is 20~70μm and does not include the endpoint value of 20μm.

[0050] It should be noted that the average particle size in this invention can be expressed as D. 50 .

[0051] In an embodiment of the present invention, the ratio of the medium particle size of the fine powder to the coarse powder is 0.414:1 to 0.175:1.

[0052] In embodiments of the present invention, the mass ratio of fine powder to coarse powder is 1:9 to 4:6.

[0053] It is worth mentioning that the present invention provides a method for preparing TA15 powder with a bimodal particle size distribution, specifically including the following steps:

[0054] Two TA15 powders with different average particle sizes were placed in a suspension and stirred for 2–8 hours at a stirring speed of 200–500 r / min to obtain a powder mixture slurry.

[0055] Under a protective atmosphere, the powder mixture slurry was degreased to obtain the bimodal particle size distribution TA15 powder.

[0056] In embodiments of the present invention, the suspension is a mixture of polyethylene glycol 4000 and anhydrous ethanol, or a mixture of polyethylene glycol 4000 and deionized water.

[0057] In one embodiment of the present invention, the mass of polyethylene glycol 4000 is 0.5 to 2% of the total mass of the two TA15 powders with different average particle sizes.

[0058] In one embodiment of the present invention, the sum of the masses of the two TA15 powders with different average particle sizes is 60 to 80% of the total mass of the powder mixture slurry.

[0059] In embodiments of the present invention, stirring can be carried out under a protective atmosphere of high-purity argon.

[0060] In an embodiment of the present invention, the degreasing treatment temperature is 100-150°C, the heating rate is 1-3°C / min, and the degreasing time is 1-2 hours.

[0061] In embodiments of the present invention, the protective gas for the degreasing treatment can be high-purity argon.

[0062] It is worth mentioning that after printing is completed, once the forming chamber and the substrate have cooled to room temperature, the substrate and the printed TA15 part are removed, and the part is cut off from the substrate by wire cutting.

[0063] According to a specific embodiment of the present invention, the high-performance, low-cost TA15 part prepared by the above preparation method has a density >99.34%, a surface roughness <3.5Ra, a tensile strength of 1020.2 to 1083.8 MPa, and an elongation of 12.3 to 15.2%.

[0064] It should be noted that the density, surface roughness, tensile strength, and elongation of the TA15 part were tested using the Archimedes' displacement method, laser confocal microscopy, and room temperature tensile tests, respectively. Furthermore, to ensure the accuracy of the test data, the wire-cut parts were ultrasonically cleaned in alcohol for 20 minutes; then dried in a vacuum drying oven at 70°C for 30 minutes.

[0065] The following detailed embodiments illustrate the 3D printing method for preparing TA15 parts based on bimodal particle size distribution powder and the performance of the prepared TA15 parts.

[0066] Example 1:

[0067] Two types of near-spherical TA15 powders with particle sizes ranging from 2 to 20 μm and 20 to 53 μm, respectively, were weighed at a mass ratio of 4:6 and placed in a beaker containing a suspension of PEG4000 in anhydrous ethanol. The PEG4000 accounted for 1% of the total mass of the two powders, and the two powders comprised 70% of the total volume of the suspension. Under high-purity argon protection, the two powders of different particle sizes were mixed uniformly using a magnetic stirrer at a speed of 300 r / min for 5 h. The resulting powder mixture was then placed in a high-temperature rotary furnace for degreasing. High-purity argon was used as the protective gas. The degreasing temperature was 130℃, the heating rate was 1.5℃ / min, and the holding time was 1.5 h. After furnace cooling, near-spherical bimodal TA15 powder with a particle size distribution was obtained and vacuum-sealed for storage. Before sealing, a small amount of powder was taken for tests on powder morphology, particle size, and flowability. The results are detailed in Table 1.

[0068] The 3D printing method for TA15 parts using TA15 powder with a near-spherical bimodal particle size distribution as shown in Figure 1 as raw material includes the following steps:

[0069] S1: Use UG software to draw a 3D model according to the required part shape and export the file;

[0070] S2: The 3D model is sliced ​​using Magics software, and the resulting 2D data information is input into the SLM forming equipment. The specific process parameters are: substrate preheating temperature 300℃, laser power 200W, scanning speed 1200mm / s, scanning spacing 0.12mm, and powder layer thickness 32μm.

[0071] S3: Using the near-spherical bimodal particle size distribution TA15 powder obtained above as raw material and forged TA15 as substrate, a part of a specified shape is prepared by selective laser melting technology;

[0072] S4: Printing complete. After the forming chamber and substrate have cooled to room temperature, remove the substrate and the printed parts, and cut the parts from the substrate using wire cutting.

[0073] S5: The part obtained in S4 is ultrasonically cleaned in alcohol for 20 minutes, and then dried in a vacuum drying oven for 30 minutes at a temperature of 70°C.

[0074] S6: The density, surface roughness, tensile strength, and elongation of the part obtained in S5 were tested by Archimedes' displacement method, laser confocal microscopy, and room temperature tensile test, respectively. The results are detailed in Table 2.

[0075] Examples 2 and 3 use the same preparation process as Example 1, except for the raw material powder parameters, process parameters, etc. The properties of the near-spherical bimodal particle size distribution powder obtained in Examples 1 to 3, the properties of the TA15 parts prepared in Examples 1 to 3, and the preparation process parameters of the bimodal particle size distribution powder and its parts in Examples 1 to 3 are summarized in Tables 1, 2 and 3.

[0076] Table 1. Summary of powder characteristics of TA15 powder with bimodal particle size distribution in Examples 1-3

[0077] Powder Properties Example 1 Example 2 Example 3 Powder Composition TA15 Alloy Powder TA15 Alloy Powder TA15 Alloy Powder Flowability / (s / 50g) 434440 Loose Packing Density / (g / cm³) 3 )2.39 2.44 2.36 Particle size range / μm2~538~63≤45 medium particle size D 50 / μm13, 3316, 409, 23 surface

[0078] Table 2 summarizes the properties of the TA15 alloy parts prepared in Examples 1-3.

[0079] Part Performance Examples 1 Example 2 Example 3 Density / % 99.34 99.76 99.45 Surface Roughness / Ra 3.4 3.2 3.5 Tensile Strength / MPa 102 0.2 108 3.8 103 0.6 Elongation / % 13.8 15.2 12.3 surface

[0080] Table 3 Summary of process parameters for raw material powders and parts preparation in Examples 1-4

[0081]

[0082]

[0083] The following will compare the performance of the TA15 alloy parts prepared in Examples 1-3 and the parts prepared in Comparative Examples 1-6.

[0084] I. Experimental Subjects

[0085] The TA15 alloy parts prepared in Examples 1-3 and the TA15 alloy parts prepared in Comparative Examples 1-6, wherein:

[0086] Comparative Example 1:

[0087] Using TA15 powder with the same characteristics as in Example 1 as the raw material, and employing the same preparation process as in Example 1, TA15 alloy parts were prepared. The only difference was the selected laser melting process parameter window: the process parameters in Example 1 were the optimized process parameter window selected by comparing the performance of TA15 near-spherical powder SLM parts under different process parameters, while the process parameters used in Comparative Example 1 were the commonly used process parameters for high-quality SLM parts made from spherical TA15 powder. For details of the specific process parameters and part performance, please refer to Tables 4 and 6.

[0088] Comparative Example 2:

[0089] Using TA15 powder with a particle size range basically the same as that in Example 1 as the raw material, and using the same preparation process as in Example 1, TA15 alloy parts were prepared. The only difference was the particle size distribution characteristics of the raw material powder: the powder particle size in Example 1 showed a bimodal particle size distribution, while the powder particle size in Comparative Example 2 showed a unimodal distribution. For details of the specific powder characteristics and the performance of the parts, please refer to Tables 5 and 6.

[0090] Comparative Example 3:

[0091] Using TA15 powder with the same characteristics as in Example 2 as the raw material, and employing the same preparation process as in Example 2, TA15 alloy parts were prepared. The only difference was the selected laser melting process parameter window: the process parameters in Example 2 were the optimized process parameter window selected by comparing the performance of TA15 near-spherical powder SLM parts under different process parameters, while the process parameters used in Comparative Example 3 were the commonly used process parameters for high-quality SLM parts made from spherical TA15 powder. For details of the specific process parameters and part performance, please refer to Tables 4 and 6.

[0092] Comparative Example 4:

[0093] Using TA15 powder with a particle size range basically the same as that in Example 2 as the raw material, and using the same preparation process as in Example 2, TA15 alloy parts were prepared. The only difference was the particle size distribution characteristics of the raw material powder: the powder particle size in Example 2 showed a bimodal particle size distribution, while the powder particle size in Comparative Example 4 showed a unimodal distribution. For details of the specific powder characteristics and the performance of the parts, please refer to Tables 5 and 6.

[0094] Comparative Example 5:

[0095] Using TA15 powder with the same characteristics as in Example 3 as the raw material, and employing the same preparation process as in Example 3, TA15 alloy parts were prepared. The only difference was the selected laser melting process parameter window: the process parameters in Example 3 were the optimized process parameter window selected by comparing the performance of TA15 near-spherical powder SLM parts under different process parameters, while the process parameters used in Comparative Example 5 were the commonly used process parameters for high-quality SLM parts made from spherical TA15 powder. For details of the specific process parameters and part performance, please refer to Tables 4 and 6.

[0096] Comparative Example 6:

[0097] Using TA15 powder with a particle size range basically the same as that in Example 3 as the raw material, and using the same preparation process as in Example 3, TA15 alloy parts were prepared. The only difference was the particle size distribution characteristics of the raw material powder: the powder particle size in Example 3 showed a bimodal particle size distribution, while the powder particle size in Comparative Example 6 showed a unimodal distribution. For details of the specific powder characteristics and the performance of the parts, please refer to Tables 5 and 6.

[0098] Table 4 summarizes the process parameters in Comparative Examples 1, 3, and 5.

[0099] Powder Properties Comparative Example 1 Comparative Example 3 Comparative Example 5 Laser Power / W 180 200 150 Scanning Speed / (mm / s) 900 1000 850 Scanning Spacing / mm 0.1 0.1 0.1 Powder Layer Thickness / μm 30 30 30 Substrate Preheating Temperature / ℃ 200 200 200 surface

[0100] Table 5 summarizes the powder properties of the raw material powders in Comparative Examples 2, 4, and 6.

[0101] Powder Properties (Comparative Example 2, Comparative Example 4, Comparative Example 6) Flowability (s / 50g): 40 42 39 Loose Bulk Density (g / cm³) 3 )2.13 2.15 2.03 Particle size range / μm2~53 10~60 3~48 Medium particle size D 50 / μm303328 surface

[0102] Table 6 summarizes the properties of TA15 alloy parts prepared in Comparative Examples 1-6.

[0103] Comparative Examples of Part Properties: Example 1, Example 2, Example 3, Example 4, Example 5, Example 6; Density / %: 98.42%, 98.56%, 98.15%, 98.32%, 98.17%, 98.97%; Surface Roughness / Ra: 3.8, 4.1, 3.9, 3.8, 4.4, 4.2; Tensile Strength / MPa: 995.3, 998.7, 101, 0.5, 102, 0.5, 1002, 998.8; Elongation / %: 9.8, 10.1, 10.2, 10.5, 9.3, 9.6 surface

[0104] Analysis of the data in the table shows that the bimodal particle size distribution TA15 powders prepared in Examples 1-4 have a flowability range of 40-46 s / 50g and a bulk density of 2.36-2.44 g / cm³. 3 The prepared parts have high density, reaching over 99%; good surface quality, with a surface roughness value of 3.2 to 3.5 Ra; and excellent mechanical properties, with a room temperature tensile strength of 1020.2 to 1083.8 MPa and an elongation of 12.3 to 15.2%.

[0105] By comparing Example 1 with Comparative Example 1, Example 2 with Comparative Example 3, and Example 3 with Comparative Example 5, it can be seen that, with the same powder characteristics and other preparation processes, the parts prepared using the process parameter window proposed in this invention, suitable for near-spherical bimodal particle size distribution TA15 powder, exhibit better performance compared to the process parameters used for printing spherical TA15 powder parts. Specifically, high density: 99.34% vs. 98.42%, 99.76% vs. 98.15%. Low surface roughness: 3.4 vs. 3.8 Ra, 3.2 vs. 3.9 Ra, 3.5 vs. 4.4 Ra; High tensile strength: 1020.2 vs. 995.3 MPa, 1083.8 vs. 1010.5 MPa, 1030.6 vs. 1002.5 MPa; High elongation: 13.8 vs. 9.8%, 15.2 vs. 10.2%, 12.3 vs. 9.3%.

[0106] Comparing Example 1 with Comparative Example 2, Example 2 with Comparative Example 4, and Example 3 with Comparative Example 6, it can be seen that, with the same particle size distribution range, compared to single-peak powder, the near-spherical powder with a bimodal particle size distribution used in this invention has a higher bulk density due to the combination of large and small particle sizes: 2.39 vs. 2.13 g / cm³. 3 2.44 vs. 2.15 g / cm³ 3 2.36 vs. 2.03 g / cm³ 3 Furthermore, the prepared parts exhibit superior performance, specifically: high density: 99.34% vs. 98.56%, 99.76% vs. 98.32%, 99.45% vs. 98.97%; low surface roughness: 3.4% vs. 4.1% Ra, 3.2% vs. 3.8% Ra, 3.5% vs. 4.2% Ra; high tensile strength: 1020.2% vs. 998.8 MPa, 1083.8% vs. 1020.5 MPa, 1030.6% vs. 998.8 MPa; and high elongation: 13.8% vs. 10.1%, 15.2% vs. 10.5%, 12.3% vs. 9.6%.

[0107] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A 3D printing method for preparing low-cost TA15 parts based on near-spherical powder with bimodal particle size distribution, characterized in that, Includes the following steps: A three-dimensional model is drawn based on the shape of the part and then sliced ​​into layers. The obtained two-dimensional data information is then input into the SLM forming equipment. Using bimodal TA15 near-spherical powder with a particle size distribution as the raw material and a forged TA15 plate as the substrate, TA15 parts of a specific shape are manufactured by SLM printing. The bimodal TA15 near-spherical powder is prepared from two types of TA15 near-spherical powder with different average particle sizes. The preparation of the bimodal TA15 near-spherical powder includes: placing two types of TA15 powder with different average particle sizes in a suspension and stirring for a certain time to obtain a powder mixture slurry; the suspension is a mixture of polyethylene glycol 4000 and anhydrous ethanol, or a mixture of polyethylene glycol 4000 and deionized water; under a protective atmosphere, the powder mixture slurry is subjected to furnace-mounted rotary degreasing treatment to obtain the bimodal TA15 near-spherical powder.

2. The 3D printing method as described in claim 1, characterized in that, Two types of TA15 near-spherical powders with different average particle sizes are referred to as fine powder and coarse powder, respectively. The fine powder has a particle size ≤20μm, and the coarse powder has a particle size of 20~70μm, excluding the endpoint value of 20μm.

3. The 3D printing method as described in claim 2, characterized in that, The ratio of the fine powder to the coarse powder in terms of medium particle size is 0.414:1 to 0.175:

1.

4. The 3D printing method as described in claim 2, characterized in that, The mass ratio of the fine powder to the coarse powder is 1:9 to 4:

6.

5. The 3D printing method as described in claim 1, characterized in that, The bimodal particle size distribution TA15 near-spherical powder has a particle size ≤70μm, a flowability <45s / 50g, and a loose packing density of 2.36~2.44g / cm³. 3 .

6. The 3D printing method as described in claim 1, characterized in that, The SLM printing process parameters are: laser power of 180~220W, scanning speed of 900~1400mm / s, scanning spacing of 0.1~0.15mm, and powder layer thickness of 30~35μm.

7. The 3D printing method as described in claim 1, characterized in that, The substrate preheating temperature is 200~400℃.

8. The 3D printing method as described in claim 1, characterized in that, The mass of the polyethylene glycol 4000 is 0.5 to 2% of the total mass of the two TA15 powders with different average particle sizes.

9. The 3D printing method as described in claim 1, characterized in that, The sum of the masses of the two TA15 powders with different average particle sizes is 60-80% of the total mass of the powder mixture slurry.

10. The 3D printing method as described in claim 1, characterized in that, The stirring speed is 200~500 r / min, and the stirring time is 2~8 h.

11. The 3D printing method as described in claim 1, characterized in that, The stirring was carried out under a protective atmosphere of high-purity argon.

12. The 3D printing method as described in claim 1, characterized in that, The degreasing treatment is carried out at a temperature of 100~150℃, a heating rate of 1~3℃ / min, and a degreasing time of 1~2h.

13. The 3D printing method as described in claim 1, characterized in that, The protective gas is high-purity argon.

14. A high-performance, low-cost TA15 component, characterized in that, It is prepared by the 3D printing method according to any one of claims 1-13; wherein, the density of the TA15 part is ≥99.34%, the surface roughness is ≤3.5Ra, the tensile strength is 1020.2~1083.8MPa, and the elongation is 12.3~15.2%.

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