High-temperature annealing strengthened pure tantalum, and preparation method and application thereof

Abstract

The application relates to high-temperature annealing strengthened pure tantalum and a preparation method and application thereof, and the preparation method of the high-temperature annealing strengthened pure tantalum is as follows: first, cold plastic deformation processing is carried out on pure tantalum at a temperature not higher than 30 DEG C for not less than 1 time to obtain fine-grained or ultrafine-grained pure tantalum, and then the fine-grained or ultrafine-grained pure tantalum is annealed in a vacuum at 300-600 DEG C to obtain the high-temperature annealing strengthened pure tantalum. The pure tantalum prepared according to the above preparation method appears an annealing strengthening effect at 500 DEG C high temperature, and further improves the high-temperature strength of the pure tantalum, thereby laying a theoretical foundation for expanding the application field of the pure tantalum and improving the application capability of the pure tantalum.

Description

Technical Field

[0001] This invention belongs to the field of metallic materials technology, specifically relating to a high-temperature annealed strengthened pure tantalum, its preparation method, and its application. Background Technology

[0002] Tantalum is a body-centered cubic refractory metal with high density and melting point, good ductility and corrosion resistance. It is widely used in the electronics, metallurgical, advanced steel, and automotive industries. Furthermore, tantalum's outstanding high-temperature strength makes it suitable for manufacturing engine blades and other components in the aerospace field. The high-temperature mechanical properties of pure tantalum determine its application capabilities; therefore, further improving the high-temperature strength of pure tantalum is of significant research importance for expanding its application areas and enhancing its overall applicability.

[0003] In the prior art, the annealing strengthening phenomenon of metallic materials is mostly manifested at room temperature. For example, patent number CN111440938A discloses an annealing strengthening process for rolling pure tantalum foil. The pure tantalum foil prepared by this process has a room temperature annealing strengthening effect, which significantly improves the tensile strength and plastic deformation of the rolled tantalum foil, thereby improving the room temperature mechanical properties. However, no high temperature annealing effect is observed. In view of this, the present invention provides a high temperature annealing strengthening pure tantalum, its preparation method and application. Summary of the Invention

[0004] The purpose of this invention is to provide a high-temperature annealed reinforced pure tantalum, its preparation method, and its application in order to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] As a first aspect of the present invention, the present invention provides a method for preparing high-temperature annealed and strengthened pure tantalum, wherein the pure tantalum is first subjected to cold plastic deformation processing at a temperature not higher than 30°C for at least one time to obtain fine-grained or ultra-fine-grained pure tantalum, and then the fine-grained or ultra-fine-grained pure tantalum is annealed in a vacuum at 300-600°C to obtain high-temperature annealed and strengthened pure tantalum.

[0007] As a further optimization of the present invention, the cold plastic deformation process is one or more of rotary forging, rolling, forging or extrusion, and the total strain of the cold plastic deformation process is not less than 1.

[0008] As a further optimization of the present invention, the specific steps of the cold plastic deformation processing include,

[0009] (1) First, pure tantalum is subjected to one pass of equal channel angular extrusion at 20°C with a strain of 1.03;

[0010] (2) After the extruded pure tantalum is placed in liquid nitrogen to cool for 20 minutes, it is taken out and the surface temperature of the sample is measured to be -10℃ using an infrared temperature measuring instrument. When the surface temperature of the pure tantalum is above 0℃, the forging of the pure tantalum is started. When the surface temperature of the pure tantalum exceeds 0℃, the forging is stopped and the pure tantalum is placed in liquid nitrogen. When the surface temperature of the pure tantalum reaches -10℃, the next forging is started. This cycle is repeated until the total deformation of the forging is 73%, thus completing the cold plastic deformation processing of pure tantalum.

[0011] As a further optimization of the present invention, the vacuum degree of the annealing treatment is not less than 10. -1 Pa, annealing time is 0.5-5 hours.

[0012] As a second aspect of the present invention, the present invention provides a high-temperature annealed strengthened pure tantalum according to any of the above descriptions.

[0013] As a further optimization of the present invention, the high-temperature annealed and strengthened pure tantalum has a tensile strength of 525-561 MPa and a total elongation of 13-16% at 500°C.

[0014] As a third aspect of the present invention, the present invention also provides the application of high-temperature annealed and strengthened pure tantalum as described above in the preparation of high-temperature resistant and high-strength mechanical parts, the high-temperature resistant and high-strength mechanical parts including engine blades or blades used in the aerospace field.

[0015] The beneficial effects of this invention are as follows:

[0016] This invention first involves cold plastic deformation processing of commercially pure tantalum at low temperatures to obtain fine-grained or ultrafine-grained pure tantalum with a large number of pre-existing dislocations. Subsequently, by controlling the heat treatment process, the dislocation behavior is controlled, causing the numerous pre-existing dislocations to evolve into dislocation cell structures or sub-grains, etc. These sub-structures exhibit good high-temperature stability, resulting in an annealing strengthening effect on the pure tantalum at 500°C. This improves the high-temperature strength of pure tantalum and lays a theoretical foundation for expanding the application fields of pure tantalum and enhancing its application capabilities. Attached Figure Description

[0017] Figure 1 The image is an electron backscattered image provided by the present invention (in the image, a is extruded and forged pure tantalum (E&F-Ta); b is high-temperature annealed and strengthened pure tantalum (E&F-A-Ta)).

[0018] Figure 2 The figures show the engineering stress-strain curves of extruded and forged pure tantalum (E&F-Ta) and high-temperature annealed and strengthened pure tantalum (E&F-A-Ta) provided by this invention (in the figure, a is room temperature 20℃; b is 500℃). Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0020] Example 1

[0021] This embodiment provides a method for preparing high-temperature annealed and strengthened pure tantalum, including the following steps:

[0022] (1) Commercially available pure tantalum was first subjected to one pass of equal channel angular extrusion with a strain of 1.03 at room temperature (20°C). Then, the extruded sample was placed in liquid nitrogen to cool for 20 minutes and then taken out. When the surface temperature of the sample was measured to be about -10°C by an infrared thermometer, the sample was forged. When the surface temperature of the sample exceeded 0°C, the forging was stopped and the sample was placed in liquid nitrogen. When the surface temperature of the sample reached -10°C, the next pass of forging was started. This cycle was repeated until the total deformation of the forging was about 73%, and extruded + forged pure tantalum (E&F-Ta) was obtained.

[0023] (2) Extruded and forged pure tantalum (E&F-Ta) is subjected to a vacuum of 10 at 500°C. -2 Annealing in a Pa heating furnace for 2 hours yields high-temperature annealed and strengthened pure tantalum (E&F-A-Ta).

[0024] Microstructure analysis was performed on extruded and forged pure tantalum (E&F-Ta) and high-temperature annealed and strengthened pure tantalum (E&F-A-Ta), respectively. Figure 1 a represents the electron backscattering results for extruded and forged pure tantalum (E&F-Ta). Figure 1 b represents the electron backscattering results of high-temperature annealed and strengthened pure tantalum (E&F-A-Ta).

[0025] from Figure 1 As can be seen, after extrusion and forging, pure tantalum exhibits a layered structure with a layer thickness of approximately 1 μm, and high-density dislocations appear within the layers. After annealing at 500℃, the layer thickness did not change significantly, but a large number of substructures evolved from high-density dislocations were formed within the layers.

[0026] Subsequently, mechanical properties of extruded and forged pure tantalum (E&F-Ta) and high-temperature annealed and strengthened pure tantalum (E&F-A-Ta) were tested at room temperature and at 500℃. Figure 2 a and Figure 2 b represents the engineering stress-strain curves of extruded and forged pure tantalum (E&F-Ta) and high-temperature annealed and strengthened pure tantalum (E&F-A-Ta) at room temperature (20℃) and 500℃, respectively.

[0027] The room temperature tensile strength of the high-temperature annealed and strengthened pure tantalum (E&F-A-Ta) prepared by this invention was measured to be 575 MPa, with a total elongation of approximately 13%, while the tensile strength of extruded and forged pure tantalum (E&F-Ta) was approximately 628 MPa, with a total elongation of approximately 19.5%. This indicates that annealing reduced the room temperature strength and ductility of extruded and forged pure tantalum. At 500℃, the tensile strength of the high-temperature annealed and strengthened pure tantalum (E&F-A-Ta) was 561 MPa, with a total elongation of approximately 13%, while the tensile strength of extruded and forged pure tantalum (E&F-Ta) was approximately 485 MPa, with a total elongation of approximately 14%. This demonstrates that annealing improved the 500℃ high-temperature strength of extruded and forged pure tantalum with almost no change in ductility, achieving a high-temperature annealing strengthening effect.

[0028] Example 2

[0029] This embodiment provides a method for preparing high-temperature annealed and strengthened pure tantalum. First, commercially available pure tantalum is subjected to two passes of equal channel angular extrusion at room temperature (20°C) with a strain of 2.06 to obtain extruded pure tantalum. Then, the extruded pure tantalum is annealed at 300°C under a vacuum of 10... -2 High-temperature annealed and strengthened pure tantalum was obtained by annealing in a Pa heating furnace for 2 hours.

[0030] The mechanical properties of the extruded pure tantalum and the high-temperature annealed strengthened pure tantalum prepared above were tested at room temperature (20℃) and at 500℃. The room temperature tensile strength of the high-temperature annealed strengthened pure tantalum prepared in this invention was measured to be 560 MPa, with a total elongation of approximately 14%, while the tensile strength of the extruded pure tantalum was approximately 610 MPa, with a total elongation of 21%. Annealing reduced the room temperature strength and plasticity of the extruded pure tantalum. At 500℃, the tensile strength of the high-temperature annealed strengthened pure tantalum was 553 MPa, with a total elongation of approximately 13%, while the tensile strength of the extruded pure tantalum was approximately 484 MPa, with a total elongation of approximately 14%. It can be seen that annealing improved the 500℃ high-temperature strength of the extruded pure tantalum with almost no change in plasticity, achieving the high-temperature annealing strengthening effect.

[0031] Example 3

[0032] This embodiment provides a method for preparing high-temperature annealed and strengthened pure tantalum. First, the purchased commercially available pure tantalum is cooled in liquid nitrogen for 20 minutes and then removed. When the surface temperature of the sample is measured to be approximately -10°C using an infrared thermometer, forging of the sample begins. Forging is stopped when the surface temperature of the sample exceeds 0°C, and the sample is placed back in liquid nitrogen. When the surface temperature of the sample reaches -10°C, the next forging pass is started. This cycle is repeated until the total forging deformation is approximately 90%, resulting in forged pure tantalum. Then, the forged sample is subjected to high-temperature annealing at 500°C under a vacuum of 10°C. -2Annealing in a Pa heating furnace for 2 hours yields high-temperature annealed and strengthened pure tantalum.

[0033] The mechanical properties of the forged pure tantalum and the high-temperature annealed pure tantalum obtained above were tested at room temperature (20℃) and at 500℃. The room temperature tensile strength of the high-temperature annealed pure tantalum obtained by this invention was measured to be 570 MPa, and the total elongation was approximately 13%, while the tensile strength of the forged pure tantalum was approximately 615 MPa, and the total elongation was approximately 18%. Therefore, annealing reduced the room temperature strength and plasticity of the forged pure tantalum. At 500℃, the tensile strength of the high-temperature annealed pure tantalum was 539 MPa, and the total elongation was approximately 14%, while the tensile strength of the forged pure tantalum was approximately 480 MPa, and the total elongation was approximately 15%. Therefore, annealing improved the 500℃ high-temperature strength of the forged pure tantalum with almost no change in plasticity, achieving the high-temperature annealing strengthening effect.

[0034] Example 4

[0035] This embodiment provides a method for preparing high-temperature annealed and strengthened pure tantalum. First, commercially available pure tantalum is subjected to a single pass of equal channel angular extrusion with a strain of 1.03 at -10°C in liquid nitrogen. The extruded sample is then cooled in liquid nitrogen for 20 minutes and removed. When the surface temperature of the sample is measured to be approximately -10°C using an infrared thermometer, forging begins. Forging is stopped when the surface temperature exceeds 0°C, and the sample is placed back in liquid nitrogen. The next forging pass is then initiated when the surface temperature reaches -10°C. This cycle is repeated until the total forging deformation is approximately 40%, yielding extruded and forged pure tantalum. Finally, the extruded and forged pure tantalum is subjected to high-temperature annealing at 500°C under a vacuum of 10°C. -2 Annealing in a Pa heating furnace for 2 hours yields high-temperature annealed and strengthened pure tantalum.

[0036] The mechanical properties of the forged pure tantalum and the high-temperature annealed pure tantalum obtained above were tested at room temperature (20℃) and at 500℃. The room temperature tensile strength of the high-temperature annealed pure tantalum obtained by this invention was 577 MPa, and the total elongation was about 13%, while the tensile strength of the extruded + forged pure tantalum was about 629 MPa, and the total elongation was about 18%. Therefore, annealing reduced the room temperature strength and plasticity of the extruded + forged pure tantalum. At 500℃, the tensile strength of the high-temperature annealed pure tantalum was 559 MPa, and the total elongation was about 13%, while the tensile strength of the extruded + forged pure tantalum was about 488 MPa, and the total elongation was about 13%. Therefore, annealing improved the 500℃ high-temperature strength of the extruded + forged pure tantalum with almost no change in plasticity, achieving the high-temperature annealing strengthening effect.

[0037] Example 5

[0038] This embodiment provides a method for preparing high-temperature annealed and strengthened pure tantalum. First, commercially available pure tantalum is subjected to a single pass of equal channel angular extrusion with a strain of 1.03 at room temperature. Then, the extruded sample is forged at room temperature (20°C) with a total forging deformation of approximately 60%, yielding extruded + forged pure tantalum. Finally, the extruded + forged pure tantalum is subjected to annealing at 500°C under a vacuum of 10°C. -2 Annealing in a Pa heating furnace for 2 hours yields high-temperature annealed and strengthened pure tantalum.

[0039] The mechanical properties of the forged pure tantalum and the high-temperature annealed pure tantalum obtained above were tested at room temperature (20℃) and at 500℃. The room temperature tensile strength of the high-temperature annealed pure tantalum obtained by this invention was measured to be 540 MPa, and the total elongation was approximately 16%, while the tensile strength of the forged pure tantalum was approximately 585 MPa, and the total elongation was approximately 20%. Therefore, annealing reduced the room temperature strength and plasticity of the forged pure tantalum. At 500℃, the tensile strength of the high-temperature annealed pure tantalum was 525 MPa, and the total elongation was approximately 16%, while the tensile strength of the extruded forged pure tantalum was approximately 470 MPa, and the total elongation was approximately 18%. Therefore, annealing improved the 500℃ high-temperature strength of the extruded + forged pure tantalum with almost no change in plasticity, achieving the high-temperature annealing strengthening effect.

[0040] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing high-temperature annealed and strengthened pure tantalum, characterized in that: First, pure tantalum undergoes cold plastic deformation processing to obtain fine-grained or ultrafine-grained pure tantalum with a large number of pre-existing dislocations; the specific steps of the cold plastic deformation processing include, (1) First, pure tantalum is subjected to one pass of equal channel angular extrusion at 20°C with a strain of 1.03; (2) After the extruded pure tantalum is placed in liquid nitrogen to cool for 20 minutes, it is taken out and the surface temperature of the sample is measured to be -10℃ using an infrared temperature measuring instrument. Forging of the pure tantalum is started. Forging is stopped when the surface temperature of the pure tantalum exceeds 0℃. The pure tantalum is then placed in liquid nitrogen. When the surface temperature of the pure tantalum reaches -10℃, the next forging is started. This cycle is repeated until the total deformation of the forging is 73%. Fine-grained or ultrafine-grained pure tantalum is then annealed in a furnace at 500°C and a vacuum of 10⁻² Pa for 2 hours, causing the pre-fabricated large number of dislocations to evolve into dislocation cell structures or sub-grains, thus obtaining high-temperature annealed strengthened pure tantalum; the high-temperature annealed strengthened pure tantalum has a strengthening effect at 500°C.

2. A high-temperature annealed reinforced pure tantalum prepared by the preparation method according to claim 1.

3. The high-temperature annealed and strengthened pure tantalum according to claim 2, characterized in that: The high-temperature annealed reinforced pure tantalum has a tensile strength of 525-561 MPa at 500℃ and a total elongation of 13-16%.

4. The application of high-temperature annealed and strengthened pure tantalum as described in claim 3 in the preparation of high-temperature resistant and high-strength mechanical parts, characterized in that, The high-temperature resistant and high-strength mechanical parts include engine blades or blades used in the aerospace field.

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