阅读说明：本技术 一种3d打印生物医用金属钽的高强高韧后处理方法及金属钽 (High-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum and metal tantalum ) 是由 周立波 孙金山 陈荐 牛焱 何建军 李聪 李微 于 2021-07-02 设计创作，主要内容包括：本发明公开了一种3D打印生物医用金属钽的高强高韧后处理方法及金属钽,高强高韧后处理方法包括,将经3D打印的金属钽置于氩气氛围中,升温至第一阈值温度；随炉冷却至第二阈值温度；随炉冷却至第三阈值温度；迅速冷却至室温；其中,第一阈值温度、第二阈值温度、第三阈值温度之间呈等差数列。本发明可以有效的实现3D打印金属钽柱状晶向等轴晶转变,同时通过位错的规则排列以及堆积形成亚晶界而保持3D打印金属钽的细小晶粒,实现保持3D打印金属钽的高强度,同时可以显著提升3D打印金属钽的延伸率,经后处理的金属钽拉伸强度大于750MPa,屈服强度大于650MPa,延伸率大于12％。(The invention discloses a high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum and metal tantalum, wherein the high-strength high-toughness post-treatment method comprises the steps of placing 3D printed metal tantalum in an argon atmosphere, and heating to a first threshold temperature; cooling with the furnace to a second threshold temperature; cooling with the furnace to a third threshold temperature; rapidly cooling to room temperature; and the first threshold temperature, the second threshold temperature and the third threshold temperature are in an arithmetic progression. The invention can effectively realize the transformation of columnar crystal orientation equiaxial crystals of the 3D printed metal tantalum, simultaneously keep fine crystal grains of the 3D printed metal tantalum by forming the subboundary through the regular arrangement and accumulation of dislocation, realize the maintenance of high strength of the 3D printed metal tantalum, and simultaneously can obviously improve the elongation of the 3D printed metal tantalum, wherein the tensile strength of the post-processed metal tantalum is more than 750MPa, the yield strength is more than 650MPa, and the elongation is more than 12%.)

1. A high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum is characterized by comprising the following steps: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

placing the 3D printed metal tantalum in an argon atmosphere, and heating to a first threshold temperature;

cooling with the furnace to a second threshold temperature;

cooling with the furnace to a third threshold temperature;

rapidly cooling to room temperature;

and the first threshold temperature, the second threshold temperature and the third threshold temperature are in an arithmetic progression.

2. The high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum according to claim 1, characterized in that: the first threshold temperature is 1800 ℃, the second threshold temperature is 1600 ℃, and the third threshold temperature is 1400 ℃.

3. The high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum as claimed in claim 1 or 2, wherein the post-treatment method comprises the following steps: and heating to a first threshold temperature at a heating rate of 20 ℃/s.

4. The high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum according to claim 3, characterized in that: the method further comprises a heat preservation step, wherein the heat preservation step is carried out after the temperature is raised to a first threshold temperature, the furnace cooling is carried out to a second threshold temperature, and the furnace cooling is carried out to a third threshold temperature, and the heat preservation time is 1-2 hours.

5. The high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum according to any one of claims 1, 2 and 4, characterized by comprising the following steps of: and 3D printing the 3D printed metal tantalum by placing raw material powder into selective laser melting equipment for 3D printing and forming.

6. The high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum according to claim 5, characterized in that: the 3D printing forming is carried out, the laser power is 200-300W, the laser scanning speed is 80-150 mm/s, the laser scanning interval is 0.23mm, the scanning layer thickness is 0.03mm, the laser spot size is 100 micrometers, and the scanning mode adopts a zigzag scanning mode of rotating 67 degrees layer by layer.

7. The high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum according to claim 6, characterized in that: the compactness of the 3D printed metal tantalum is higher than 97%.

8. The high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum according to any one of claims 1, 2, 4, 6 and 7, which is characterized by comprising the following steps of: the metal tantalum powder is metal tantalum powder which is subjected to arc melting or hydrogenation dehydrogenation.

9. The high-strength high-toughness post-treatment method for 3D printing of biomedical metal tantalum according to claim 8, characterized in that: the tantalum powder comprises, by mass, 0.0005-0.0012 wt% of H, 0.15-0.21 wt% of O, 0.0028-0.0033 wt% of N, 0.0027-0.0030 wt% of C, 0.0035-0.0041 wt% of Nb, and the balance of Ta.

10. The metal tantalum prepared by the high-strength high-toughness post-treatment method of the 3D printed biomedical metal tantalum as claimed in any one of claims 1 to 9, wherein the metal tantalum is prepared by the following steps: the tensile strength of the metal tantalum is more than 750MPa, the yield strength is more than 650MPa, and the elongation is more than 12%.

Technical Field

The invention belongs to the technical field of 3D printing post-processing, and particularly relates to a high-strength high-toughness post-processing method for 3D printing biomedical metal tantalum and metal tantalum.

Background

The metal tantalum is a metal element which is generally recognized in the field of biomedical science and has the best biocompatibility, and has the function of inducing bone growth. However, the metal tantalum has an ultra-high melting point (2996 ℃) and extremely strong oxygen affinity, so that the processing and forming process is difficult by adopting the traditional processing scheme. The 3D printing technology effectively solves the difficult problem of difficult forming of refractory metal, and the central temperature of the high-energy laser beam exceeds 3000 ℃. Therefore, the 3D printing technology can be adopted to realize the effective forming of the high-melting-point metal tantalum.

However, a technical bottleneck of the 3D printing technology for forming the metal tantalum is how to effectively control the microstructure of the formed metal tantalum workpiece, because the 3D printing process has an extremely high cooling rate and non-equilibrium solidification characteristics. The microstructure can directly influence the physical and chemical properties of the metal tantalum forming workpiece, so that the hot point and the difficulty of the research on how to regulate and control the microstructure of the 3D printing forming metal tantalum workpiece are always studied. Meanwhile, columnar crystals are easily formed in the 3D printing forming metal tantalum workpiece, and the shape of the crystals is easy to cause anisotropy. Compared with columnar crystals, the equiaxed crystals can bring higher mechanical properties and can effectively avoid the formation of anisotropy. And due to the high cooling rate and the non-equilibrium solidification characteristic of 3D printing, the prepared metal tantalum workpiece is often high in strength but generally low in elongation rate, and further popularization and application of the metal tantalum workpiece are severely limited.

Therefore, how to effectively regulate and control the microstructure of the 3D printed metal tantalum workpiece and obtain a fine isometric crystal structure is of great significance, however, no relevant research report exists at present, and especially the microstructure regulation and control of the 3D printed high-biocompatibility high-melting-point metal tantalum is provided.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made keeping in mind the above and/or other problems occurring in the prior art.

The invention provides a high-strength high-toughness processing method for 3D printed biomedical metal tantalum, which can effectively realize the transformation of columnar crystal orientation equiaxial crystal of 3D printed metal tantalum through the post-processing method, and meanwhile, fine crystal grains of the 3D printed metal tantalum are kept through the regular arrangement and accumulation of dislocation to form a subgrain boundary, so that the high strength of the 3D printed metal tantalum is kept, and meanwhile, the elongation of the 3D printed metal tantalum can be obviously improved.

In order to solve the technical problems, the invention provides the following technical scheme: a high-strength high-toughness post-treatment method for 3D printed biomedical metal tantalum comprises the steps of placing 3D printed metal tantalum in an argon atmosphere, and heating to a first threshold temperature; cooling with the furnace to a second threshold temperature; cooling with the furnace to a third threshold temperature; rapidly cooling to room temperature;

and the first threshold temperature, the second threshold temperature and the third threshold temperature are in an arithmetic progression.

As a preferred scheme of the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, the method comprises the following steps: the first threshold temperature is 1800 ℃, the second threshold temperature is 1600 ℃, and the third threshold temperature is 1400 ℃.

As a preferred scheme of the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, the method comprises the following steps: and heating to a first threshold temperature at a heating rate of 20 ℃/s.

As a preferred scheme of the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, the method comprises the following steps: the method further comprises a heat preservation step, wherein the heat preservation step is carried out after the temperature is raised to a first threshold temperature, the furnace cooling is carried out to a second threshold temperature, and the furnace cooling is carried out to a third threshold temperature, and the heat preservation time is 1-2 hours.

As a preferred scheme of the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, the method comprises the following steps: and 3D printing the 3D printed metal tantalum by placing raw material powder into selective laser melting equipment for 3D printing and forming.

As a preferred scheme of the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, the method comprises the following steps: the 3D printing forming is carried out, the laser power is 200-300W, the laser scanning speed is 80-150 mm/s, the laser scanning interval is 0.23mm, the scanning layer thickness is 0.03mm, the laser spot size is 100 micrometers, and the scanning mode adopts a zigzag scanning mode of rotating 67 degrees layer by layer.

As a preferred scheme of the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, the method comprises the following steps: the compactness of the 3D printed metal tantalum is higher than 97%.

As a preferred scheme of the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, the method comprises the following steps: the raw material powder is obtained by vacuum drying of metal tantalum powder with a medium particle size of 30-45 mu m.

As a preferred scheme of the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, the method comprises the following steps: the metal tantalum powder is metal tantalum powder which is subjected to arc melting or hydrogenation dehydrogenation.

As a preferred scheme of the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, the method comprises the following steps: the metal tantalum powder comprises, by mass, 0.0012% of H, 0.15% of O, 0.0028% of N, 0.0030% of C, 0.0041% of Nb and the balance of Ta.

The invention also aims to provide the metal tantalum prepared by the high-strength high-toughness post-treatment method for 3D printing of the biomedical metal tantalum, wherein the tensile strength of the metal tantalum is more than 600MPa, the yield strength of the metal tantalum is more than 550MPa, and the elongation of the metal tantalum is more than 8%.

Compared with the prior art, the invention has the following beneficial effects:

according to the post-processing method, the columnar crystal orientation equiaxial crystal transformation of the 3D printed metal tantalum can be effectively realized, meanwhile, the fine crystal grains of the 3D printed metal tantalum are kept by forming the subboundary through the regular arrangement and accumulation of dislocation, the high strength of the 3D printed metal tantalum is kept, and meanwhile, the elongation of the 3D printed metal tantalum can be remarkably improved.

The method combines the 3D printing process and the post-treatment process, has larger subversion compared with the traditional forming process, can effectively improve the problem that the high-melting-point metal tantalum is difficult to form by the traditional process, and can effectively improve the problem that the 3D printing metal tantalum has low elongation.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:

FIG. 1 is a flow chart of a heat treatment process provided by the present invention.

FIG. 2 shows the microstructure of 500 μm before and after the post-treatment of the biomedical metal tantalum 3D printed in the present invention.

FIG. 3 shows the microstructure of 10 μm before and after the post-treatment of the biomedical metal tantalum 3D printed in the present invention.

FIG. 4 shows a microstructure of a 100nm scale after 3D printing of biomedical metallic tantalum according to the present invention.

FIG. 5 shows the mechanical property changes before and after the post-treatment of the biomedical metal tantalum 3D printed in the invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Example 1

(1) Selecting spherical tantalum powder with the medium particle size of 38.3 mu m, which is prepared by arc melting and comprises, by mass, 0.0012% of H, 0.15% of O, 0.0028% of N, 0.0030% of C, 0.0041% of Nb and the balance of Ta;

(2) drying the mixture in a vacuum drying oven at 50 ℃ for 24 hours to obtain 3D printing raw material powder;

(3) placing the dried raw material powder into BLT-S210 selective laser melting equipment for forming, wherein the forming base material is a metal tantalum plate, and the forming process parameters are as follows: the laser power is 250W, the laser scanning speed is 100mm/s, the scanning interval is 0.23mm, the scanning layer thickness is 0.03mm, and the scanning mode is that the scanning layer rotates by 67 degrees layer by layer; the density of the workpiece formed by the process conditions reaches 98.3 percent and is higher than 97 percent.

The formed workpieces are divided into two groups, one group is subjected to post-treatment, and the other group is not subjected to treatment.

(4) Placing the post-processed sample in a tubular furnace protected by argon, heating to 1800 ℃, wherein the heating rate is 20 ℃/s, and keeping the temperature at 1800 ℃ for 2 h;

(5) then cooling to 1600 ℃ along with the furnace, and preserving heat for 2 h;

(6) then cooling to 1400 ℃ along with the furnace, and preserving heat for 2 h;

(7) and then taking out air from the furnace and cooling to room temperature to obtain the high-strength high-toughness post-treated metal tantalum.

The microstructure of 500 μm before and after the post-treatment of the biomedical metal tantalum is 3D printed and is shown in FIG. 2, wherein FIG. 2(c) is a microstructure diagram of 500 μm without post-treatment of the spherical tantalum powder 3D printed, and FIG. 2(D) is a microstructure diagram of 500 μm after post-treatment of the spherical tantalum powder 3D printed; it can be seen that the columnar crystals formed during the 3D printing of metallic tantalum were transformed into equiaxed crystals.

3D printing microstructures with the size of 10 mu m before and after post-treatment of the biomedical metal tantalum, as shown in FIG. 3, wherein FIG. 3(c) is a microstructure diagram with the size of 10 mu m obtained by 3D printing the spherical tantalum powder without post-treatment, and FIG. 3(D) is a microstructure diagram with the size of 10 mu m obtained by 3D printing the spherical tantalum powder with post-treatment; it can be seen that the post-treatment process is capable of regularly arranging the dislocations that are randomly distributed.

The microstructure of 100nm scale after the 3D printing of the biomedical metal tantalum is subjected to post-treatment is shown in fig. 4, and it can be seen that after the post-treatment process enables regularly arranged dislocations to be gradually accumulated to form subgrain boundaries, short-range ordered equiaxial crystal structures which are uniformly distributed are formed through dislocation walls, the effect of refining grains is achieved, meanwhile, the subgrain boundaries play a role of blocking the dislocation from further sliding, and therefore the high strength of a workpiece at room temperature is maintained.

The metal tantalum after high-strength and high-toughness post-treatment and the workpiece without post-treatment are subjected to room-temperature tensile test by using an Instron 3369 universal electronic mechanics tester, and the result is shown in figure 5, and the result shows that the workpiece without high-strength and high-toughness post-treatment of the 3D printed metal tantalum has the strength of 740MPa, the elongation of only 1.7 percent and almost no work hardening; the strength of the workpiece after high-strength and high-toughness post-treatment is increased to 750MPa, the elongation is increased to 12 percent, and the work hardening phenomenon is obvious.

Example 2

(1) Selecting polygonal tantalum powder with the medium grain size of 43.7 mu m, which is prepared by hydrogenation and dehydrogenation and comprises, by mass, 0.0005 wt% of H, 0.21 wt% of O, 0.0033 wt% of N, 0.0027 wt% of C, 0.0035 wt% of Nb and the balance of Ta;

(2) drying the mixture in a vacuum drying oven at 50 ℃ for 24 hours to obtain 3D printing raw material powder;

(3) placing the dried raw material powder into BLT-S210 selective laser melting equipment for forming, wherein the forming base material is a metal tantalum plate, and the forming process parameters are as follows: the laser power is 275W, the laser scanning speed is 100mm/s, the scanning interval is 0.23mm, the scanning layer thickness is 0.03mm, and the scanning mode is that the scanning layer rotates by 67 degrees layer by layer; the density of the workpiece formed by the process conditions reaches 97.9 percent and is higher than 97 percent.

The formed workpieces are divided into two groups, one group is subjected to post-treatment, and the other group is not subjected to treatment.

(4) Placing the post-processed sample in a tubular furnace protected by argon, heating to 1800 ℃, wherein the heating rate is 20 ℃/s, and keeping the temperature at 1800 ℃ for 2 h;

(5) then cooling to 1600 ℃ along with the furnace, and preserving heat for 2 h;

(6) then cooling to 1400 ℃ along with the furnace, and preserving heat for 2 h;

(7) and then taking out air from the furnace and cooling to room temperature to obtain the high-strength high-toughness post-treated metal tantalum.

The microstructure of 500 μm scale before and after the post-treatment of the biomedical metal tantalum is 3D printed and is shown in FIG. 2, wherein FIG. 2(a) is a microstructure diagram of 500 μm scale without post-treatment printed by polygonal tantalum powder 3D, and FIG. 2(b) is a microstructure diagram of 500 μm scale without post-treatment printed by polygonal tantalum powder 3D; it can be seen that the columnar crystals formed during the 3D printing of metallic tantalum were transformed into equiaxed crystals.

3D printing microstructures with the size of 10 mu m before and after post-treatment of the biomedical metal tantalum, as shown in FIG. 3, wherein FIG. 3(a) is a microstructure diagram with the size of 10 mu m obtained by 3D printing of polygonal tantalum powder without post-treatment, and FIG. 3(b) is a microstructure diagram with the size of 10 mu m obtained by 3D printing of polygonal tantalum powder with post-treatment; it can be seen that the post-treatment process is capable of regularly arranging the dislocations that are randomly distributed.

The metal tantalum after high-strength and high-toughness post-treatment and the workpiece without post-treatment are subjected to room-temperature tensile test by using an Instron 3369 universal electronic mechanics tester, and the result is shown in FIG. 5, and the result shows that the workpiece without high-strength and high-toughness post-treatment of the 3D printed metal tantalum has the strength of 610MPa, the elongation of only 1.3 percent and almost no work hardening; the strength of the workpiece after high-strength and high-toughness post-treatment is increased to 690MPa, the elongation is increased to 9.3 percent, and the work hardening phenomenon is obvious.

Example 3

Example 3 differs from example 1 in that the post-treatment conditions were: and (3) placing the post-processed sample in a tubular furnace under the protection of argon, heating to 1800 ℃, keeping the temperature at 1800 ℃ for 2h at the heating rate of 20 ℃/s, and then cooling to room temperature along with the furnace to obtain a coarse isometric crystal structure, wherein the strength of the workpiece is 330MPa, and the elongation is 25%. The elongation increased significantly compared to the direct 3D printed sample, but the intensity decreased significantly.

Example 4

This example 4 differs from example 1 in that the post-treatment conditions were: and (3) placing the post-processed sample in a tubular furnace under the protection of argon, heating to 1800 ℃, keeping the temperature at 1800 ℃ for 2h at the heating rate of 20 ℃/s, then cooling to 1600 ℃ along with the furnace, keeping the temperature for 2h, and cooling to room temperature along with the furnace to obtain the workpiece with the strength of 350MPa and the elongation of 16%. The elongation increased significantly compared to the direct 3D printed sample, but the intensity decreased significantly.

Example 5

This example 5 differs from example 1 in that the post-treatment conditions were: and (3) placing the post-processed sample in a tubular furnace under the protection of argon, heating to 1800 ℃, keeping the temperature at 1800 ℃ for 2h at a heating rate of 20 ℃/s, cooling to 1600 ℃ along with the furnace, keeping the temperature for 2h, cooling to 1400 ℃ along with the furnace, keeping the temperature for 2h, cooling to 1200 ℃ along with the furnace, keeping the temperature for 2h, taking out air from the furnace, and cooling to room temperature to obtain the workpiece with the strength of 620MPa and the elongation of 10%. Compared with a direct 3D printing sample, the strength is slightly reduced, the elongation is obviously improved, but the strength and the elongation are lower than those of the high-strength high-toughness treatment method provided by the example 1.

Example 6

The embodiment 6 is different from the embodiment 1 in the 3D printing process conditions, and the 3D printing process includes: laser power 200W, laser scanning speed: 100mm/s, the scanning interval is 0.23mm, the scanning layer thickness is 0.03mm, and the scanning mode is that the scanning layer rotates by 67 degrees layer by layer. The density of the workpiece formed by the process conditions is 96%. The strength of the work piece obtained by the post-treatment of example 1 was 630MPa and the elongation was 8.2%.

Example 7

This example 7 differs from example 1 in that the post-treatment conditions were: and (3) placing the post-processed sample in a tubular furnace under the protection of argon, heating to 2000 ℃, keeping the temperature at the heating rate of 20 ℃/s for 2h at 2000 ℃, then cooling to 1800 ℃ along with the furnace, keeping the temperature for 2h, then cooling to 1600 ℃ along with the furnace, keeping the temperature for 2h, then taking out air from the furnace and cooling to room temperature, and finally obtaining the workpiece with the strength of 450MPa and the elongation of 13%.

Example 8

This example 8 differs from example 1 in that the post-treatment conditions were: and (3) placing the post-processed sample in a tubular furnace protected by argon, heating to 1400 ℃, keeping the temperature at 1400 ℃ for 2h at a heating rate of 20 ℃/s, cooling to 1200 ℃ along with the furnace, keeping the temperature for 2h, cooling to 1000 ℃ along with the furnace, keeping the temperature for 2h, taking out air from the furnace, cooling to room temperature, and finally obtaining the workpiece with the strength of 670MPa and the elongation of 4%.

Example 9

This example 9 differs from example 1 in that the post-treatment conditions were: and (3) placing the post-processed sample in a tubular furnace under the protection of argon, heating to 1800 ℃, keeping the temperature at 1800 ℃ for 4h at a heating rate of 20 ℃/s, cooling to 1600 ℃ along with the furnace, keeping the temperature for 4h, cooling to 1400 ℃ along with the furnace, keeping the temperature for 4h, taking out air from the furnace, cooling to room temperature, and finally obtaining the workpiece with the strength of 530MPa and the elongation of 12%.

The invention puts the post-processing sample into a tube furnace protected by argon, the temperature is raised to 1800 ℃, the temperature raising rate is 20 ℃/s, keeping the temperature at 1800 ℃ for 2h, converting columnar crystals formed in the process of 3D printing of the metal tantalum into isometric crystals, improving the room temperature elongation of the workpiece by obtaining isometric crystal while eliminating the anisotropy of the 3D printed metal tantalum, then cooling to 1600 ℃ along with the furnace, preserving heat for 2h, cooling to 1400 ℃ along with the furnace after the dislocation distributed randomly is arranged regularly, preserving heat for 2h, after the dislocation arranged regularly is gradually stacked to form a subgrain boundary, the dislocation wall forms a short-range ordered equiaxial crystal structure which is uniformly distributed, plays a role in refining crystal grains, meanwhile, the subgrain boundary plays a role in preventing dislocation from further sliding, and then the work piece is rapidly cooled to room temperature by air, so that the strength reduction caused by abnormal expansion of crystal grains is prevented, and the room-temperature high strength of the work piece is maintained.

According to the post-processing method, the columnar crystal orientation equiaxial crystal transformation of the 3D printed metal tantalum can be effectively realized, meanwhile, the fine crystal grains of the 3D printed metal tantalum are kept by forming the subboundary through the regular arrangement and accumulation of dislocation, the high strength of the 3D printed metal tantalum is kept, and meanwhile, the elongation of the 3D printed metal tantalum can be remarkably improved.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.