Ultrahigh-plasticity medium-entropy alloy conical bushing as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of powder metallurgy, and particularly discloses an ultrahigh-plasticity medium-entropy alloy conical bushing and a preparation method and application thereof.The medium-entropy alloy is mainly composed of W, Co, Mo, Ta, La and Ni according to the specific mass fraction, during preparation, a cast ingot is obtained through vacuum melting firstly and machined into a plasma rotating electrode to prepare bimodal distribution powder, and then the powder is subjected to high-temperature sintering to obtain the ultrahigh-plasticity medium-entropy alloy conical bushing. And filling the blank into a shape control sheath, heating, degassing, carrying out seal welding, carrying out hot isostatic pressing treatment, carrying out acid pickling to remove the sheath, and carrying out heat treatment and finish machining on the blank to obtain a finished product. The density of the manufactured conical bushing is larger than or equal to 11.5 g / cm, the ductility is larger than or equal to 65%, the problem that the density, plasticity and cost of a traditional material are difficult to balance is effectively solved, and the technical bottlenecks of material segregation, product incompactness, performance anisotropy, low material utilization rate and the like in a traditional preparation process are solved; the method can be widely applied to the fields of oil exploration, weaponry, machinery manufacturing, energy industry and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of powder metallurgy, focuses on the processing direction of bushings, and particularly relates to a super-high plasticity medium entropy alloy conical bushing, its preparation method and application. Background Art

[0002] In many key fields of modern industry, such as oil exploration, weaponry, machinery manufacturing, and the energy industry, conical bushings (i.e., penetrators) play an important role. As a core functional component for achieving directional energy release under extreme dynamic load conditions (such as high-speed impact and high-temperature jet scenarios), with a specific geometric structure, it can generate continuous metal jets during the instantaneous high strain rate deformation process to effectively penetrate high-hardness targets. Given that its working environment involves high temperatures and high-speed metal jets, extremely stringent requirements are imposed on the density and plasticity of the manufacturing materials.

[0003] At present, the commonly used materials for conical bushings include pure copper, pure nickel, pure tungsten, and various alloys such as tantalum tungsten alloy and tungsten copper alloy. Among them, pure copper is used in some scenarios due to its good ductility and corrosion resistance, but limited by its low density, it is difficult to meet the special working conditions with strict requirements for material density, and there are performance shortcomings in high-end application fields. With the progress of technology, the demand for high-performance materials in various industries is increasing day by day. Tungsten alloys, with characteristics such as high density, high melting point, good ductility, and high sound speed, have gradually become the research focus of new conical bushing materials. However, tungsten alloys have problems such as short total jet length, sensitivity to radial disturbances, high cost, and high processing difficulty, which severely restrict their large-scale popularization and application. Tantalum, as a bushing material, has advantages such as high density, high sound speed, high plasticity, high melting point, and good dynamic characteristics. However, the content of tantalum in the earth's crust is limited, and the supply is restricted, resulting in high costs, and the processing difficulty and complexity are also relatively high.

[0004] In addition, from the perspective of the preparation process, traditional smelting and processing processes are extremely prone to material segregation when dealing with high melting point elements (such as tungsten). Taking tungsten alloys as an example, during the melting process, due to the high melting point characteristics of tungsten, it is difficult to ensure its uniform distribution in the matrix, resulting in unstable performance of the final product. In powder metallurgy processes, conical bushings prepared by traditional methods generally have the problem of non-dense products, which seriously affects the strength and service life of the products. In addition, for bushings prepared by processes such as forging, due to uneven stress distribution during the processing, the product performance shows anisotropy, and the performance in different directions varies greatly, unable to meet some application scenarios with high requirements for isotropy. Moreover, traditional preparation processes often require a large number of machining operations to meet the dimensional accuracy requirements of the products, which not only consumes a large amount of time and cost but also results in low material utilization rate, usually less than 70%.

[0005] In summary, in the current situation where the performance requirements for conical bushings are continuously increasing in many industries, and higher standards for the comprehensive performance of materials are put forward in emerging application scenarios (such as deep-sea oil exploration and high-end weapon equipment upgrading), it is difficult to achieve a balance among density, plasticity, and cost for existing materials, and there are many technical bottlenecks that are difficult to overcome in traditional preparation processes. Against this background, it is urgent to develop a conical bushing with high density, high plasticity, and low cost, as well as its preparation process.

[0006] In view of this, this invention is specifically proposed. Summary of the Invention

[0007] The object of the present invention is to overcome the above-mentioned shortcomings of the existing technology, and provide a super-high plasticity medium entropy alloy conical bushing, its preparation method and application, mainly to solve the problem that it is difficult to balance density, plasticity, and cost for existing conical bushings, as well as technical problems such as material segregation, non-dense products, performance anisotropy, and low material utilization rate existing in traditional preparation processes.

[0008] The object of the present invention is solved by the following technical solutions: In the first aspect, the present invention provides a preparation method for a super-high plasticity medium entropy alloy conical bushing, and the preparation method includes the following steps: Step 1: Use vacuum induction melting technology to cast the molten solution of a medium entropy alloy with specific components to form an electrode, and perform vacuum consumable arc melting treatment on the electrode again to obtain a medium entropy alloy ingot; Step 2: After processing the medium entropy alloy ingot into a plasma rotating electrode, prepare a medium entropy alloy plasma rotating electrode powder with a bimodal distribution; Step 3: Load the medium entropy alloy plasma rotating electrode powder into a shape-control sleeve of the conical bushing. After filling and vibrating it solid, first perform heat degassing treatment on the shape-control sleeve until the vacuum degree requirement is met, and then perform sealing welding treatment on the shape-control sleeve; Step 4: Perform hot isostatic pressing treatment on the sealed shape-control sleeve to obtain a hot isostatic pressing blank; Step 5: Remove the shape-control sleeve outside the hot isostatic pressing blank by pickling or machining to obtain a medium entropy alloy conical bushing blank. Subsequently, perform heat treatment on the medium entropy alloy conical bushing blank, and then perform finish machining on it to obtain a super-high plasticity medium entropy alloy conical bushing.

[0009] Further, in Step 1, the main component and the mass fraction of each component of the medium entropy alloy are as follows: W: 15% - 47%, Co: 0 - 20%, Mo: 0 - 20%, Ta: 0 - 20%, La: 0 - 20%, and the balance is Ni element; Among them, Ni and W elements are essential elements, and the remaining elements include at least two of Co, Mo, Ta, and La.

[0010] Further, in step 2, the medium-entropy alloy plasma rotating electrode powder has a bimodal distribution of fine powder and coarse powder; Among them, the particle size of the fine powder is 15μm - 53μm, and the mass ratio is 30% - 60%. The rest is coarse powder, and the particle size of the coarse powder is 75μm - 300μm.

[0011] Further, in step 3, the ratio of the internal size of the shape control sleeve to the external size of the target medium-entropy alloy conical bushing is controlled between 1.05 and 1.5.

[0012] Further, in step 3, the specific process of the heating and degassing treatment is as follows: First, the temperature is raised from room temperature to 100℃ - 200℃ at a heating rate of 5℃ / min - 20℃ / min and then held for 30min - 240min; then the temperature is raised to 250℃ - 400℃ at a heating rate of 5℃ / min - 20℃ / min and held for 30min - 240min; finally, the temperature is raised to 450℃ - 600℃ at a heating rate of 5℃ / min - 20℃ / min and held until the vacuum degree meets the requirement of less than 1.0×10 -4 Pa.

[0013] Further, in step 4, the specific process of the hot isostatic pressing treatment is as follows: Initially, the temperature is raised to 900℃ - 1200℃ at a heating rate of 11℃ / min - 20℃ / min and held for 30min - 120min, and at the same time, the pressure is raised to 120MPa - 180MPa; then the temperature is raised to 1250℃ - 1450℃ at a heating rate of 11℃ / min - 15℃ / min and held for 60min - 240min.

[0014] Further, in step 5, a composite acid is used for pickling to remove the shape control sleeve, and the composite acid is composed of sulfuric acid and phosphoric acid; Among them, the mass fraction of sulfuric acid is 40% - 70%, the concentration is 15% - 30%, and the rest is phosphoric acid. The concentration of phosphoric acid is 5% - 20%.

[0015] Further, in step 5, the process of the heat treatment is as follows: First, the medium-entropy alloy conical bushing blank is placed in a heat treatment furnace at 1100℃ - 1450℃ for 2h - 3h of solution treatment; after the solution treatment is completed, the medium-entropy alloy conical bushing blank is subjected to water quenching treatment, and the transfer time of the medium-entropy alloy conical bushing blank from the solution treatment to the water quenching treatment should be less than 30s.

[0016] In a second aspect, the present invention also provides a superplastic medium-entropy alloy tapered bushing, which is prepared based on the above preparation method, and the density of the medium-entropy alloy tapered bushing is ≥ 11.5 g / cm 3 , and the elongation is ≥ 65%.

[0017] In a third aspect, the present invention also provides an application based on the above superplastic medium-entropy alloy tapered bushing, and the medium-entropy alloy tapered bushing is used in the fields of oil exploration, weapon equipment, mechanical manufacturing, and energy industry.

[0018] Specifically, in the field of oil exploration, the medium-entropy alloy tapered bushing can be used for the jet generator of deep-earth drill bits in oil exploration; in terms of weapon equipment, the medium-entropy alloy tapered bushing can be applied to the penetration body of armor-piercing warheads; in the field of mechanical manufacturing, the medium-entropy alloy tapered bushing can be used for key connection parts or transmission components of various precision mechanical equipment; in the field of energy industry, whether it is in the mining equipment of traditional energy or new energy equipment such as wind turbines and solar tracking devices, the medium-entropy alloy tapered bushing can play an important role.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. In terms of performance, the medium-entropy alloy is prepared by powder metallurgy in the present invention, effectively overcoming the segregation problem of high-melting-point tungsten elements in the nickel matrix, and enabling a large amount of tungsten elements to be uniformly solid-solved in the nickel matrix. This design not only significantly increases the alloy density, meeting the stringent requirements for high-density materials, but also ensures ultra-high plasticity, and has a low preparation cost, successfully solving the problem that it is difficult for existing materials to achieve a balance among density, plasticity, and production cost. At the same time, the medium-entropy alloy tapered bushing prepared in the present invention has been actually tested, with a density ≥ 11.5 g / cm³ and an elongation ≥ 65%, and various performance indicators far exceed those of the tapered bushing made of traditional materials, providing a solid material basis for the stable and efficient operation of the tapered bushing under complex working conditions.

[0020] 2. In terms of the preparation process, the present invention has the following advantages: First, it solves the problem of non-dense products: The present invention uses the powder hot isostatic pressing process to prepare the medium entropy alloy tapered bushing, and the product density > 99.9%, completely solving the key technical problem of non-dense traditional powder tapered bushings, significantly improving the strength and service life of the product, and reducing the failure risk caused by internal defects of the product. Second, it eliminates the performance anisotropy: Compared with traditional processes such as forging, the medium entropy alloy tapered bushing prepared by hot isostatic pressing in the present invention has no performance anisotropy, and the product shows consistent performance in all directions, which can better meet the application scenarios with high requirements for isotropy. Third, it improves the material utilization rate and economy: The hot isostatic pressing process can achieve near-net shaping, greatly reducing the machining process. This not only reduces the production cost, reduces the waste of raw materials, but also shortens the production cycle, improves the production efficiency, and enhances the competitiveness of the product in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings herein are incorporated into the specification and form a part of this specification, and are used together with the specification to explain the principles of the present invention.

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a flowchart of the preparation method of the ultra-high plasticity medium entropy alloy tapered bushing of the present invention; Figure 2 It is a microstructural diagram of the medium entropy alloy tapered bushing A prepared in Example 1 of the present invention; Figure 3 It is an engineering stress and engineering strain curve diagram of the medium entropy alloy tapered bushing A obtained in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. On the contrary, they are only examples consistent with some aspects of the present invention detailed in the appended claims.

[0025] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] Please refer to Figure 1, a preparation method of a superplastic medium-entropy alloy conical bushing provided by the present invention specifically includes the following steps: Step 1: Use vacuum induction melting technology to cast the molten solution of the medium-entropy alloy with specific components to form an electrode, and perform vacuum consumable arc melting treatment on the electrode again to obtain a medium-entropy alloy ingot.

[0027] Specifically, the main components of the medium-entropy alloy adopted in the present invention and the mass fraction of each component are: W: 15% - 47%, Co: 0 - 20%, Mo: 0 - 20%, Ta: 0 - 20%, La: 0 - 20%, and the balance is Ni element and inevitable impurity elements; Among them, Ni and W elements are essential elements, and the remaining elements include at least two of Co, Mo, Ta, and La.

[0028] Step 2: After processing the medium-entropy alloy ingot into a plasma rotating electrode, prepare a plasma rotating electrode powder with a bimodal distribution.

[0029] Specifically, the plasma rotating electrode powder of the present invention adopts a bimodal distribution of fine powder and coarse powder; Among them, the particle size of the fine powder is 15μm - 53μm, and the mass ratio is 30% - 60%, and the rest is coarse powder (that is, the mass ratio of the coarse powder is 40% - 70%), and the particle size of the coarse powder is 75μm - 300μm.

[0030] Step 3: Load the plasma rotating electrode powder into the shape control sleeve of the conical bushing. After filling and vibrating it solid, first perform heat degassing treatment on the shape control sleeve until the vacuum degree requirement is met, and then perform sealing welding treatment on the shape control sleeve.

[0031] Specifically, the ratio of the internal size of the shape control sleeve in the present invention to the external size of the target medium-entropy alloy conical bushing is controlled between 1.05 and 1.5.

[0032] Furthermore, when performing heat degassing on the shape control sleeve, first increase the temperature from room temperature to 100°C - 200°C at a heating rate of 5°C / min - 20°C / min and hold for 30min - 240min; then increase the temperature to 250°C - 400°C at a heating rate of 5°C / min - 20°C / min and hold for 30min - 240min; finally increase the temperature to 450°C - 600°C at a heating rate of 5°C / min - 20°C / min and hold until the vacuum degree is less than 1.0×10 -4 Pa is required.

[0033] Step 4: Perform hot isostatic pressing treatment on the sealed shape control sleeve to obtain a hot isostatic pressing blank.

[0034] Specifically, the specific process of hot isostatic pressing treatment in the present invention is as follows: Initially, the temperature is raised to 900°C - 1200°C at a heating rate of 11°C / min - 20°C / min and held for 30 min - 120 min, while the pressure is raised to 120 MPa - 180 MPa; subsequently, the temperature is further raised to 1250°C - 1450°C at a heating rate of 11°C / min - 15°C / min and held for 60 min - 240 min.

[0035] Step 5: After removing the shape control jacket outside the hot isostatic pressing blank by pickling or machining, a medium-entropy alloy conical bushing blank is obtained. Subsequently, after heat-treating the medium-entropy alloy conical bushing blank, finish machining is performed on it to obtain a medium-entropy alloy conical bushing with ultra-high plasticity.

[0036] Specifically, a composite acid is used for pickling to remove the shape control jacket in the present invention, and this composite acid is composed of sulfuric acid and phosphoric acid; Among them, the mass fraction of the sulfuric acid is 40% - 70%, the concentration is 15% - 30%, and the rest is phosphoric acid, and the concentration of the phosphoric acid is 5% - 20%.

[0037] Furthermore, the process of heat treatment is as follows: First, place the medium-entropy alloy conical bushing blank in a heat treatment furnace at 1100°C - 1450°C for solution treatment for 2 h - 3 h; after the solution treatment is completed, perform water quenching treatment on the medium-entropy alloy conical bushing blank, and the transfer time of the medium-entropy alloy conical bushing blank from solution treatment to water quenching treatment should be less than 30 s.

[0038] In order to further verify the efficacy of the present invention, the inventor conducted the following specific experiments: Example 1

[0039] The target of this example is to prepare a medium-entropy alloy conical bushing A of a certain model, and its detailed preparation process is as follows: 1) The mass percentages of the main components in the medium-entropy alloy are as follows: W 30%, Ta 20%, Mo 1%, and the balance is Ni element and inevitable impurity elements. The molten solution of the medium-entropy alloy is cast into an electrode by vacuum induction melting technology, and the electrode is subjected to vacuum consumable arc melting treatment again to obtain a medium-entropy alloy ingot.

[0040] 2) After processing the obtained medium-entropy alloy ingot into a plasma rotating electrode, medium-entropy alloy plasma rotating electrode powder is prepared.

[0041] Among them: The mass proportion of the coarse powder with a particle size of 75 μm - 300 μm is 40%, and the rest is fine powder, and the particle size of the fine powder is 15 μm - 53 μm.

[0042] 3) The medium entropy alloy plasma rotating electrode powder is loaded into a pre-designed and processed control package. After it is filled and vibrated, the control package is heated and degassed. Specifically, the temperature is first raised from room temperature to 200°C at a heating rate of 5°C / min and then kept at this temperature for 60 minutes; then the temperature is raised to 400°C at a heating rate of 5°C / min and then kept at this temperature for 60 minutes; finally, the temperature is raised to 600°C at a heating rate of 5°C / min and then kept at this temperature until the vacuum degree is less than 1.0×10 -4 After Pa, the shape-control package is sealed and welded.

[0043] 4) The shape-controlling sleeve after sealing and welding is subjected to hot isostatic pressing treatment. Specifically, the temperature is first increased to 1200°C at a heating rate of 20°C / min and then kept at this temperature for 30 minutes, while the pressure is increased to 120MPa; then the temperature is increased to 1440°C at a heating rate of 15°C / min and kept at this temperature for 60 minutes to obtain a hot isostatic pressed billet.

[0044] 5) After removing the shape-controlling sleeve on the outside of the hot isostatic pressed blank by machining, a medium entropy alloy conical bushing blank is obtained.

[0045] 6) First, place the medium entropy alloy conical bushing blank in a 1100°C heat treatment furnace for 3 hours of solution treatment; after the solution treatment is completed, the medium entropy alloy conical bushing blank is water-cooled and quenched, and the transfer time of the medium entropy alloy conical bushing blank from solution treatment to water-cooled and quenched treatment is 10s to 20s.

[0046] 7) After the heat treatment, the medium entropy alloy conical bushing blank is finely processed to remove a small amount of excess. After testing, the density is 12.6g / cm 3 Medium entropy alloy conical bushing A. In addition, the microstructure of the medium entropy alloy conical bushing A is uniform, such as Figure 2 As shown in the figure, there is no obvious component segregation area. This uniform microstructure enables the bushing to bear complex external stresses and loads in a coordinated manner, avoiding stress concentration caused by organizational differences, thereby significantly improving its overall mechanical properties. Figure 3 From the engineering stress and engineering strain curve of the medium entropy alloy conical bushing A, it can be seen that the elongation of the medium entropy alloy conical bushing A can reach 74.5%. Example 2

[0047] The present embodiment aims to prepare a certain type of medium entropy alloy conical bushing B, and the detailed preparation process is as follows: 1) The mass percentages of the main components in the medium-entropy alloy are as follows: W 45%, Co 2%, Mo 1%, Ta 1%, La 1%, and the balance is Ni element and inevitable impurity elements. The molten solution of the medium-entropy alloy is cast into an electrode by vacuum induction melting technology, and the electrode is further processed by vacuum consumable arc melting to obtain a medium-entropy alloy ingot.

[0048] 2) After processing the obtained medium-entropy alloy ingot into a plasma rotating electrode, medium-entropy alloy plasma rotating electrode powder is prepared.

[0049] Among them: the mass proportion of the coarse powder with a particle size of 75μm - 300μm is 50%, and the rest is fine powder, and the particle size of the fine powder is 15μm - 53μm.

[0050] 3) The above-mentioned medium-entropy alloy plasma rotating electrode powder is loaded into a pre-designed and processed shape-controlled envelope. After filling and vibrating to compact, the shape-controlled envelope is subjected to heating and degassing treatment. Specifically, the temperature is first raised from room temperature to 100°C at a heating rate of 20°C / min and held for 240 min; then the temperature is raised to 260°C at a heating rate of 20°C / min and held for 230 min; finally, the temperature is raised to 460°C at a heating rate of 20°C / min and held until the vacuum degree is less than 1.0×10 -4 Pa, and then the shape-controlled envelope is sealed and welded.

[0051] 4) The sealed shape-controlled envelope is subjected to hot isostatic pressing treatment. Specifically, the temperature is first raised to 900°C at a heating rate of 11°C / min and held for 120 min, and at the same time the pressure is raised to 180 MPa; then the temperature is raised to 1250°C at a heating rate of 11°C / min and held for 240 min to obtain a hot isostatic pressing blank.

[0052] 5) After removing the external shape-controlled envelope of the hot isostatic pressing blank by pickling, a medium-entropy alloy conical bushing blank is obtained. Specifically, a composite acid is used for pickling to remove the shape-controlled envelope. The composite acid is composed of sulfuric acid and phosphoric acid; among them, the mass fraction of sulfuric acid is 40% and the concentration is 30%, and the rest is phosphoric acid, and the concentration of this phosphoric acid is 20%.

[0053] 6) First, the medium-entropy alloy conical bushing blank is placed in a heat treatment furnace at 1250°C for 2.5 h of solution treatment; after the solution treatment is completed, the medium-entropy alloy conical bushing blank is then subjected to water quenching treatment, and the transfer time of the medium-entropy alloy conical bushing blank from solution treatment to water quenching treatment is 10 s - 20 s.

[0054] 7) After the heat-treated medium-entropy alloy conical bushing blank is finely processed to remove a small amount of surplus. After testing, a medium-entropy alloy conical bushing B with a density of 12.8 g / cm 3 and an elongation of 65% is obtained. Example 3

[0055] In this example, the target is to prepare a medium-entropy alloy conical bushing C of a certain model. The detailed preparation process is as follows: 1) The mass percentages of the main components in the medium-entropy alloy are as follows: W 15%, Co 10%, Mo 19%, Ta 10%, La 18%, and the balance is Ni element and inevitable impurity elements. The molten liquid of the medium-entropy alloy is cast into an electrode by vacuum induction melting technology, and the electrode is subjected to vacuum consumable arc melting treatment again to obtain a medium-entropy alloy ingot.

[0056] 2) After processing the obtained medium-entropy alloy ingot into a plasma rotating electrode, medium-entropy alloy plasma rotating electrode powder is prepared.

[0057] Among them: the mass proportion of the coarse powder with a particle size of 75μm - 300μm is 60%, and the rest is fine powder, and the particle size of the fine powder is 15μm - 53μm.

[0058] 3) The above-mentioned medium-entropy alloy plasma rotating electrode powder is loaded into a pre-designed and processed shape-controlled sleeve. After filling and vibrating it solid, the shape-controlled sleeve is subjected to heating and degassing treatment. Specifically, the temperature is first raised from room temperature to 150°C at a heating rate of 10°C / min and held for 150 min; then the temperature is raised to 330°C at a heating rate of 10°C / min and held for 150 min; finally, the temperature is raised to 530°C at a heating rate of 8°C / min and held until the vacuum degree is less than 1.0×10 -4 Pa, and then the shape-controlled sleeve is subjected to sealing welding treatment.

[0059] 4) The sealed shape-controlled sleeve is subjected to hot isostatic pressing treatment. Specifically, the temperature is first raised to 1000°C at a heating rate of 15°C / min and held for 60 min, and at the same time the pressure is raised to 150 MPa; then the temperature is raised to 1350°C at a heating rate of 13°C / min and held for 120 min to obtain a hot isostatic pressing blank.

[0060] 5) After removing the external shape-controlled sleeve of the hot isostatic pressing blank by pickling, a medium-entropy alloy conical bushing blank is obtained. Specifically, a composite acid is used for pickling to remove the shape-controlled sleeve. The composite acid is composed of sulfuric acid and phosphoric acid; among them, the mass fraction of sulfuric acid is 66%, the concentration is 17%, and the rest is phosphoric acid, and the concentration of this phosphoric acid is 5%.

[0061] 6) First, the medium-entropy alloy conical bushing blank is placed in a heat treatment furnace at 1450°C for 2 h of solution treatment; after the solution treatment is completed, the medium-entropy alloy conical bushing blank is subjected to water quenching treatment, and the transfer time of the medium-entropy alloy conical bushing blank from solution treatment to water quenching treatment is 10 s - 20 s.

[0062] 7) After finishing machining the heat-treated medium-entropy alloy conical bushing blank to remove a small amount of surplus, through detection, a medium-entropy alloy conical bushing C with a density of 11.65 g / cm 3 and an elongation of 70% was obtained.

[0063] Example 4 The target of this example is to prepare a certain model of medium-entropy alloy conical bushing D, and its detailed preparation process is as follows: 1) The mass percentages of the main components in the medium-entropy alloy are as follows: W 25%, Co 17%, Mo 10%, and the balance is Ni element and inevitable impurity elements. The molten solution of the medium-entropy alloy is cast into an electrode by vacuum induction melting technology, and the electrode is subjected to vacuum consumable arc melting treatment again to obtain a medium-entropy alloy ingot.

[0064] 2) After processing the obtained medium-entropy alloy ingot into a plasma rotating electrode, medium-entropy alloy plasma rotating electrode powder is prepared.

[0065] Among them: the mass proportion of the coarse powder with a particle size of 75 μm to 300 μm is 70%, and the rest is fine powder, and the particle size of the fine powder is 15 μm to 53 μm.

[0066] 3) Load the above-mentioned medium-entropy alloy plasma rotating electrode powder into a pre-designed and processed shape-controlled sleeve. After filling and vibrating it solid, heat degassing treatment is carried out on the shape-controlled sleeve. Specifically, first, the temperature is raised from room temperature to 200 °C at a heating rate of 10 °C / min and then held for 30 min; then the temperature is raised to 250 °C at a heating rate of 10 °C / min and held for 240 min; finally, the temperature is raised to 500 °C at a heating rate of 10 °C / min and held until the vacuum degree is less than 1.0×10 -4 Pa, and then the shape-controlled sleeve is sealed and welded.

[0067] 4) Carry out hot isostatic pressing treatment on the sealed and welded shape-controlled sleeve. Specifically, first, the temperature is raised to 1050 °C at a heating rate of 14 °C / min and held for 60 min, and at the same time, the pressure is raised to 150 MPa; then, it is raised to 1300 °C at a heating rate of 14 °C / min and held for 120 min to obtain a hot isostatic pressing blank.

[0068] 5) After removing the shape-controlled sleeve outside the hot isostatic pressing blank by pickling, a medium-entropy alloy conical bushing blank is obtained. Specifically, a composite acid is used for pickling to remove the shape-controlled sleeve. This composite acid is composed of sulfuric acid and phosphoric acid; among them, the mass fraction of sulfuric acid is 50%, the concentration is 20%, and the rest is phosphoric acid, and the concentration of this phosphoric acid is 10%.

[0069] 6) First, place the medium-entropy alloy conical bushing blank in a heat treatment furnace at 1350 °C for 2.2 h of solution treatment; after the solution treatment is completed, then perform water-cooled quenching treatment on the medium-entropy alloy conical bushing blank, and the transfer time of the medium-entropy alloy conical bushing blank from solution treatment to water-cooled quenching treatment is 10 s to 20 s.

[0070] 7) After the heat-treated medium-entropy alloy conical bushing blank is finish-machined to remove a small amount of surplus. After testing, a medium-entropy alloy conical bushing D with a density of 12.0 g / cm 3 and an elongation of 68% is obtained.

[0071] Comparative Examples 1-2 In the present invention, Example 1 and Example 2 of a preparation method of a medium-density and ultra-high plasticity nickel-tungsten alloy liner material, with the application number 202110182870.5 and the name of the application being submitted by Beijing Institute of Technology on February 10, 2021, are respectively used as Comparative Example 1 and Comparative Example 2.

[0072] The final products obtained in Examples 1-4 and Comparative Examples 1-2 of the present invention have the following performances as shown in Table 1 below: Table 1 Performance test results of the products obtained in Examples 1-4 and Comparative Examples 1-2 of the present invention

[0073]

[0074] It can be seen from the test results in Table 1 that the medium-entropy alloy conical bushings prepared in Examples 1-4 of the present invention have more excellent plasticity (elongation ≥ 65%) and density (density ≥ 11.5 g / cm 3 ). This is because the present invention innovatively adopts the powder hot isostatic pressing method to prepare the medium-entropy alloy conical bushing, and this preparation method has significant advantages. In the traditional preparation process, the segregation problem of high-melting-point tungsten in nickel is rather intractable, seriously affecting the performance and quality of the alloy. However, through the powder hot isostatic pressing technology in the present invention, this segregation phenomenon can be maximally inhibited. By precisely controlling the process parameters, the tungsten element is evenly distributed in the alloy, and thus the content of the tungsten element in the alloy can be greatly increased. The relatively high and uniform tungsten content not only improves the density of the alloy, but also plays a key role in optimizing the overall performance. In addition, the traditional process often needs to introduce a high-temperature homogenization process during the forming process, which not only consumes a large amount of time and energy, but also lengthens the production cycle and increases the production cost. The present invention directly completes near-net forming through powder hot isostatic pressing, which not only shortens the production process, but also improves the material utilization rate. This high-efficiency, energy-saving and high-performance product-guaranteeing preparation technology undoubtedly lays a solid foundation for the large-scale production and wide application of medium-entropy alloy conical bushings.

[0075] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0076] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A method for preparing an ultra-high plasticity medium entropy alloy tapered bushing, characterized in that: The preparation method comprises the following steps: Step 1: using vacuum induction melting technology to cast a molten medium entropy alloy of a specific composition to form an electrode, and performing vacuum consumable arc melting treatment on the electrode again to obtain a medium entropy alloy ingot; Step 2: Processing the medium entropy alloy ingot into a plasma rotating electrode to prepare a medium entropy alloy plasma rotating electrode powder having a bimodal distribution; Step 3, the medium entropy alloy plasma rotating electrode powder is loaded into the shape-controlling sleeve of the conical bushing, and after being filled and vibrated, the shape-controlling sleeve is first heated and degassed until the vacuum requirement is met, and then the shape-controlling sleeve is sealed and welded; Step 4, performing hot isostatic pressing on the shape-controlling sleeve after sealing and welding to obtain a hot isostatic pressed blank; Step 5: After removing the shape-controlling sheath on the outside of the hot isostatic pressed blank by pickling or machining, a medium entropy alloy conical bushing blank is obtained. Subsequently, the medium entropy alloy conical bushing blank is heat treated and then fine-processed to obtain a medium entropy alloy conical bushing with ultra-high plasticity.

2. The method for preparing the ultra-high plasticity medium entropy alloy tapered bushing according to claim 1, characterized in that: In step 1, the main components of the medium entropy alloy and the mass fraction of each component are as follows: W: 15%~47%, Co: 0~20%, Mo: 0~20%, Ta: 0~20%, La: 0~20%, the balance is Ni element; Among them, Ni and W are essential elements, and the remaining elements include at least two of Co, Mo, Ta, and La.

3. The method for preparing the ultrahigh plasticity medium entropy alloy tapered bushing according to claim 1, characterized in that: In step 2, the medium entropy alloy plasma rotating electrode powder adopts a bimodal distribution of fine powder and coarse powder; The particle size of the fine powder is 15 μm to 53 μm, accounting for 30% to 60% by mass, and the rest is coarse powder, and the particle size of the coarse powder is 75 μm to 300 μm.

4. The method for preparing the ultrahigh plasticity medium entropy alloy tapered bushing according to claim 1, characterized in that: In step 3, the ratio of the inner dimension of the shape-controlling sleeve to the outer dimension of the target medium entropy alloy conical bushing is controlled between 1.05 and 1.

5.

5. The method for preparing the ultra-high plasticity medium entropy alloy tapered bushing according to claim 1, characterized in that: In step 3, the specific process of the heating and degassing treatment is as follows: First, the temperature is raised from room temperature to 100°C to 200°C at a heating rate of 5°C / min to 20°C / min, and then kept warm for 30min to 240min; then the temperature is raised to 250°C to 400°C at a heating rate of 5°C / min to 20°C / min, and then kept warm for 30min to 240min; finally, the temperature is raised to 450°C to 600°C at a heating rate of 5°C / min to 20°C / min, and then kept warm until the vacuum degree is less than 1.0×10 -4 Pa's request.

6. The method for preparing the ultrahigh plasticity medium entropy alloy tapered bushing according to claim 1, characterized in that: In step 4, the specific process of the hot isostatic pressing treatment is: Initially, the temperature is raised to 900°C to 1200°C at a heating rate of 11°C / min to 20°C / min, and then kept warm for 30min to 120min, while the pressure is raised to 120MPa to 180MPa; then the temperature is raised to 1250°C to 1450°C at a heating rate of 11°C / min to 15°C / min, and kept warm for 60min to 240min.

7. The method for preparing the ultrahigh plasticity medium entropy alloy tapered bushing according to claim 1, characterized in that: In step 5, a composite acid is used to remove the shape-controlling sheath by pickling, and the composite acid is composed of sulfuric acid and phosphoric acid; The mass fraction of the sulfuric acid is 40% to 70%, and the concentration is 15% to 30%. The rest is phosphoric acid, and the concentration of the phosphoric acid is 5% to 20%.

8. The method for preparing the ultrahigh plasticity medium entropy alloy tapered bushing according to claim 1, characterized in that: In step 5, the heat treatment process is: first, the medium-entropy alloy conical bushing blank is placed in a heat treatment furnace at 1100°C to 1450°C for 2h to 3h of solution treatment; after the solution treatment is completed, the medium-entropy alloy conical bushing blank is water-cooled and quenched, and the transfer time of the medium-entropy alloy conical bushing blank from solution treatment to water-cooled quenching treatment should be less than 30s.

9. An ultra-high plasticity medium entropy alloy tapered bushing, characterized in that: The medium entropy alloy conical bushing is prepared based on the preparation method according to any one of claims 1 to 8, and the density of the medium entropy alloy conical bushing is ≥11.5g / cm 3 , elongation ≥65%.

10. An application of the ultra-high plasticity medium entropy alloy tapered bushing as claimed in claim 9, characterized in that: The medium entropy alloy conical bushing is used in the fields of oil exploration, weapon equipment, machinery manufacturing and energy industry.

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