A conical bushing made of ultra-high plasticity medium-entropy alloy and its preparation method and application

Abstract

The present invention belongs to the field of powder metallurgy technology and specifically discloses an ultra-high plasticity medium-entropy alloy conical bushing, its preparation method, and application. The medium-entropy alloy is mainly composed of W, Co, Mo, Ta, La, and Ni with specific mass fractions. During preparation, an ingot is first obtained by vacuum melting, which is then processed into a plasma rotating electrode to prepare a bimodal powder. The powder is then placed in a shape-controlling sleeve, heated for degassing, sealed, and then hot isostatically pressed. The sleeve is then pickled to remove the sleeve, and the blank is heat-treated and finely processed to obtain a finished product. The conical bushing produced by the present invention has a density of ≥11.5g / cm³ and an elongation of ≥65%. It effectively overcomes the problem of traditional materials that are difficult to balance between density, plasticity, and cost, and solves technical bottlenecks in traditional preparation processes such as material segregation, non-dense products, anisotropic properties, and low material utilization. It can be widely used in fields such as oil exploration, weaponry, machinery manufacturing, and the energy industry.

Description

Technical Field

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

[0002] Conical bushings (also known as penetrators) play a vital role in many key areas of modern industry, such as oil exploration, weaponry, machinery manufacturing, and the energy sector. As core functional components that enable targeted energy release under extreme dynamic loads (such as high-speed impact and high-temperature jets), these bushings utilize a specific geometric structure to generate a continuous metal jet during instantaneous high-strain-rate deformation, effectively penetrating high-hardness targets. Given the high temperatures and high-velocity metal jets involved in their operation, these requirements place extremely stringent demands on the density and plasticity of the manufacturing material.

[0003] Currently, common materials for tapered bushings include copper, pure nickel, pure tungsten, and various alloys, such as tantalum-tungsten and tungsten-copper. Copper, due to its excellent ductility and corrosion resistance, is used in some applications. However, its low density makes it difficult to meet demanding requirements for specialized applications, resulting in performance shortcomings in high-end applications. With technological advancements, demand for high-performance materials is growing across various industries. Tungsten alloys, with their high density, high melting point, excellent ductility, and high sonic velocity, have become a research focus for new tapered bushing materials. However, tungsten alloys suffer from issues such as short total jet length, sensitivity to radial disturbances, high cost, and difficulty in processing, which severely hinder their widespread adoption. Tantalum, as a bushing material, offers advantages such as high density, high sonic velocity, high plasticity, high melting point, and excellent dynamic properties. However, its limited presence in the Earth's crust and limited supply result in high costs and a relatively high processing difficulty and complexity.

[0004] Furthermore, from a manufacturing perspective, traditional smelting and processing techniques are prone to material segregation when handling high-melting-point elements such as tungsten. Taking tungsten alloys as an example, during the smelting process, due to tungsten's high melting point, its uniform distribution in the matrix is ​​difficult to ensure, resulting in unstable performance in the final product. In powder metallurgy processes, conical bushings produced using traditional methods generally suffer from a lack of density, which seriously affects the product's strength and service life. Furthermore, bushings produced through processes such as forging exhibit anisotropic performance due to uneven stress distribution during processing, resulting in significant performance variations in different directions, making them unsuitable for applications requiring high isotropy. Furthermore, traditional manufacturing processes often require extensive machining operations to achieve the required dimensional accuracy. This not only consumes significant time and cost, but also results in low material utilization, typically less than 70%.

[0005] In summary, with the performance requirements for tapered bushings constantly increasing across numerous industries, and emerging applications (such as deep-sea oil exploration and high-end weaponry upgrades) placing even higher demands on comprehensive material performance, existing materials struggle to strike a balance between density, plasticity, and cost, while traditional manufacturing processes face numerous insurmountable technical bottlenecks. Against this backdrop, the development of a tapered bushing and its manufacturing process that combines high density, high plasticity, and low cost is urgent.

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

[0007] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an ultra-high plasticity medium entropy alloy conical bushing and its preparation method and application, which are mainly used to solve the problem of difficult balance between density, plasticity and cost of existing conical bushings, as well as the technical difficulties such as material segregation, non-dense products, performance anisotropy and low material utilization rate in traditional preparation processes.

[0008] The purpose of the present invention is to solve the problem through the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing an ultra-high plasticity medium entropy alloy tapered bushing, the preparation method comprising the following steps:

[0010] Step 1: Using vacuum induction melting technology to cast a melt of a medium-entropy alloy with a specific composition to form an electrode, and then subjecting the electrode to vacuum consumable arc melting treatment again to obtain a medium-entropy alloy ingot;

[0011] 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;

[0012] Step 3: The medium entropy alloy plasma rotating electrode powder is loaded into the shape-controlling sleeve of the conical bushing. After the powder is fully loaded and vibrated, the shape-controlling sleeve is first heated and degassed until the vacuum degree requirement is met, and then the shape-controlling sleeve is sealed and welded;

[0013] Step 4: hot isostatic pressing the shape-controlling sleeve after sealing and welding to obtain a hot isostatic pressed blank;

[0014] Step 5: After removing the shape-controlling sheath on the outside of the hot isostatically pressed blank by pickling or machining, a medium-entropy alloy conical bushing blank is obtained. The medium-entropy alloy conical bushing blank is then heat treated and then fine-processed to obtain a medium-entropy alloy conical bushing with ultra-high plasticity.

[0015] Furthermore, in step 1, the main components of the medium entropy alloy and the mass fractions of the components are as follows:

[0016] W: 15% to 47%, Co: 0 to 20%, Mo: 0 to 20%, Ta: 0 to 20%, La: 0 to 20%, and the balance is Ni;

[0017] Among them, Ni and W are essential elements, and the remaining elements include at least two of Co, Mo, Ta, and La.

[0018] Furthermore, in step 2, the medium entropy alloy plasma rotating electrode powder adopts a bimodal distribution of fine powder and coarse powder;

[0019] 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.

[0020] Furthermore, 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.

[0021] Furthermore, in step 3, the specific process of the heating and degassing treatment is as follows:

[0022] First, increase the temperature from room temperature to 100°C to 200°C at a heating rate of 5°C / min to 20°C / min, and then keep it warm for 30min to 240min; then increase the temperature to 250°C to 400°C at a heating rate of 5°C / min to 20°C / min, and then keep it warm for 30min to 240min; finally, increase the temperature to 450°C to 600°C at a heating rate of 5°C / min to 20°C / min, and then keep it warm until the vacuum degree is less than 1.0×10 -4 Pa's request.

[0023] Furthermore, in step 4, the specific process of the hot isostatic pressing treatment is:

[0024] 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.

[0025] Furthermore, 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;

[0026] 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%.

[0027] Furthermore, 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℃~1450℃ for 2h~3h of solution treatment; after the solution treatment is completed, the medium-entropy alloy conical bushing blank is subjected to water-cooling quenching treatment, and the transfer time of the medium-entropy alloy conical bushing blank from solution treatment to water-cooling quenching treatment should be less than 30s.

[0028] In the second aspect, the present invention also provides an ultra-high plasticity medium entropy alloy conical bushing, the medium entropy alloy conical bushing is prepared based on the above preparation method, and the density of the medium entropy alloy conical bushing is ≥11.5g / cm 3 , elongation ≥65%.

[0029] In a third aspect, the present invention also provides an application of the above-mentioned ultra-high plasticity medium-entropy alloy conical bushing, which is used in the fields of oil exploration, weapon equipment, machinery manufacturing and energy industry.

[0030] Specifically, in the field of oil exploration, the medium-entropy alloy conical bushing can be used in the jet generator of deep drill bits for oil exploration; in terms of weapons and equipment, the medium-entropy alloy conical bushing can be used in the penetrator of armor-piercing warheads; in the field of mechanical manufacturing, the medium-entropy alloy conical bushing can be used in the key connection parts or transmission components of various types of precision mechanical equipment; in the field of energy industry, whether in traditional energy extraction equipment or new energy equipment such as wind turbines, solar tracking devices, etc., the medium-entropy alloy conical bushing can play an important role.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. In terms of performance, the present invention prepares medium-entropy alloys by powder metallurgy, which effectively overcomes the problem of segregation of high-melting-point tungsten elements in the nickel matrix, and allows a large amount of tungsten elements to be evenly dissolved in the nickel matrix. This design not only significantly improves the density of the alloy and meets the stringent requirements for high-density materials, but also ensures ultra-high plasticity and low preparation costs, successfully solving the problem that existing materials are difficult to balance between density, plasticity and production costs. At the same time, the medium-entropy alloy conical bushings prepared by the present invention have been tested in practice, and the density is ≥11.5g / cm³ and the elongation is ≥65%. The various performance indicators far exceed those of conical bushings made of traditional materials, providing a solid material foundation for the stable and efficient operation of the conical bushings under complex working conditions.

[0033] 2. In terms of preparation process, the present invention has the following advantages: First, it solves the problem of non-density of products: the present invention uses powder hot isostatic pressing process to prepare medium-entropy alloy conical bushings, and the product density is >99.9%, which completely solves the key technical problem of non-density of traditional powder conical bushings, significantly improves the strength and service life of the product, and reduces the risk of failure caused by internal defects in the product; second, it eliminates performance anisotropy: compared with traditional processes such as forging, the medium-entropy alloy conical bushings prepared by hot isostatic pressing of the present invention do not have performance anisotropy, and the performance of the product in all directions is consistent, which can better meet the application scenarios with high requirements for isotropy; third, it improves material utilization and economy: the hot isostatic pressing process can achieve near-net forming and greatly reduce machining processes, which not only reduces production costs and reduces waste of raw materials, but also shortens the production cycle, improves production efficiency, and enhances the competitiveness of products in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the invention.

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 This is a flow chart of a method for preparing an ultra-high plasticity medium entropy alloy tapered bushing according to the present invention;

[0037] Figure 2 This is a microstructure diagram of the medium-entropy alloy tapered bushing A prepared in Example 1 of the present invention;

[0038] Figure 3 The engineering stress and engineering strain curves of the medium entropy alloy conical bushing A obtained in Example 1 of the present invention are shown. DETAILED DESCRIPTION

[0039] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Instead, they are merely examples consistent with certain aspects of the present invention as detailed in the appended claims.

[0040] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.

[0041] See also Figure 1 The present invention provides a method for preparing an ultra-high plasticity medium entropy alloy tapered bushing, which specifically comprises the following steps:

[0042] Step 1: Using vacuum induction melting technology to cast a melt of a medium-entropy alloy with a specific composition to form an electrode, and then subjecting the electrode to vacuum consumable arc melting treatment again to obtain a medium-entropy alloy ingot.

[0043] Specifically, the present invention adopts the main components of the medium entropy alloy and the mass fraction of each component is W: 15% to 47%, Co: 0 to 20%, Mo: 0 to 20%, Ta: 0 to 20%, La: 0 to 20%, and the balance is Ni element and unavoidable impurity elements;

[0044] Among them, Ni and W are essential elements, and the remaining elements include at least two of Co, Mo, Ta, and La.

[0045] Step 2: After processing the medium entropy alloy ingot into a plasma rotating electrode, a plasma rotating electrode powder with a bimodal distribution is prepared.

[0046] Specifically, the plasma rotating electrode powder of the present invention adopts a bimodal distribution of fine powder and coarse powder;

[0047] Among them, the particle size of fine powder is 15μm~53μm, accounting for 30%~60% by mass, and the rest is coarse powder (that is, the mass proportion of coarse powder is 40%~70%), and the particle size of coarse powder is 75μm~300μm.

[0048] Step 3: The plasma rotating electrode powder is loaded into the shape-controlling sleeve of the conical bushing. After the powder is 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.

[0049] Specifically, the ratio of the inner dimensions of the control-shaped sheath to the outer dimensions of the target medium entropy alloy conical bushing is controlled between 1.05 and 1.5.

[0050] Furthermore, when the shape-controlling bag is heated and degassed, the temperature is first 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.

[0051] Step 4: performing hot isostatic pressing on the shape-controlling sleeve after sealing and welding to obtain a hot isostatic pressed blank.

[0052] Specifically, the specific process of the hot isostatic pressing treatment of the present invention 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.

[0053] Step 5: After removing the shape-controlling sheath on the outside of the hot isostatically pressed blank by pickling or machining, a medium-entropy alloy conical bushing blank is obtained. The medium-entropy alloy conical bushing blank is then heat treated and then fine-processed to obtain a medium-entropy alloy conical bushing with ultra-high plasticity.

[0054] Specifically, the present invention uses a composite acid to remove the shape-controlling sheath by pickling, and the composite acid is composed of sulfuric acid and phosphoric acid;

[0055] 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%.

[0056] Furthermore, the heat treatment process is as follows: 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 subjected to water-cooling quenching treatment, and the transfer time of the medium-entropy alloy conical bushing blank from solution treatment to water-cooling quenching treatment should be less than 30s.

[0057] In order to further verify the efficacy of the present invention, the inventors conducted the following specific experiments: Example 1

[0058] This embodiment aims to prepare a certain type of medium entropy alloy conical bushing A. The detailed preparation process is as follows:

[0059] 1) The mass percentages of the main components of the medium-entropy alloy are as follows: W 30%, Ta 20%, Mo 1%, and the balance is Ni and inevitable impurities. The medium-entropy alloy melt is cast into an electrode using vacuum induction melting technology, and the electrode is further subjected to vacuum consumable arc melting to obtain a medium-entropy alloy ingot.

[0060] 2) Processing the obtained medium-entropy alloy ingot into a plasma rotating electrode to prepare medium-entropy alloy plasma rotating electrode powder.

[0061] Among them: coarse powder with a particle size of 75μm to 300μm accounts for 40% by mass, and the rest is fine powder with a particle size of 15μm to 53μm.

[0062] 3) The medium entropy alloy plasma rotating electrode powder is loaded into a pre-designed and processed control bag. After it is filled and vibrated, the control bag is heated and degassed. Specifically, the temperature is first increased 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 increased to 400°C at a heating rate of 5°C / min and then kept at this temperature for 60 minutes; finally, the temperature is increased 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.

[0063] 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 120 MPa; 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 isostatically pressed billet.

[0064] 5) After removing the shape-controlling sheath outside the hot isostatic pressing blank by machining, a medium entropy alloy conical bushing blank is obtained.

[0065] 6) First, the medium-entropy alloy conical bushing blank is placed in an 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 quenched, and the transfer time from the solution treatment to the water-cooled quenching treatment of the medium-entropy alloy conical bushing blank is 10s to 20s.

[0066] 7) After heat treatment, the medium entropy alloy conical bushing blank is finely machined 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, as shown in FIG. Figure 2 As shown in the figure, there is no obvious component segregation area. This uniform microstructure enables the bushing to bear complex external stress and loads, and each part can work together to avoid 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 entropy alloy conical bushing A can reach 74.5%. Example 2

[0067] This embodiment aims to prepare a certain type of medium entropy alloy conical bushing B, and the detailed preparation process is as follows:

[0068] 1) The mass percentages of the main components of the medium-entropy alloy are as follows: W 45%, Co 2%, Mo 1%, Ta 1%, La 1%, and the balance is Ni and inevitable impurities. The medium-entropy alloy melt is cast into an electrode using vacuum induction melting technology, and the electrode is further subjected to vacuum consumable arc melting to obtain a medium-entropy alloy ingot.

[0069] 2) Processing the obtained medium-entropy alloy ingot into a plasma rotating electrode to prepare medium-entropy alloy plasma rotating electrode powder.

[0070] Among them: coarse powder with a particle size of 75μm to 300μm accounts for 50% by mass, and the rest is fine powder, and the particle size of the fine powder is 15μm to 53μm.

[0071] 3) The medium entropy alloy plasma rotating electrode powder is loaded into a pre-designed and processed control bag. After it is filled and vibrated, the control bag is heated and degassed. Specifically, the temperature is first raised from room temperature to 100°C at a heating rate of 20°C / min and then kept at this temperature for 240 minutes; then the temperature is raised to 260°C at a heating rate of 20°C / min and then kept at this temperature for 230 minutes; finally, the temperature is raised to 460°C at a heating rate of 20°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.

[0072] 4) The shape-controlling sleeve after sealing and welding is subjected to hot isostatic pressing treatment. Specifically, the temperature is first increased to 900°C at a heating rate of 11°C / min and then kept at this temperature for 120 minutes, while the pressure is increased to 180 MPa; then the temperature is increased to 1250°C at a heating rate of 11°C / min and kept at this temperature for 240 minutes to obtain a hot isostatic pressed billet.

[0073] 5) After the hot isostatically pressed blank is pickled to remove the external shape-controlling sheath, a medium-entropy alloy tapered bushing blank is obtained. The pickling process removes the shape-controlling sheath using a composite acid consisting of sulfuric acid and phosphoric acid. The sulfuric acid has a mass fraction of 40% and a concentration of 30%, while the remainder is phosphoric acid at a concentration of 20%.

[0074] 6) First, the medium-entropy alloy conical bushing blank is placed in a 1250°C heat treatment furnace for 2.5 hours of solution treatment; after the solution treatment is completed, the medium-entropy alloy conical bushing blank is water-cooled quenched, and the transfer time from the solution treatment to the water-cooled quenching treatment of the medium-entropy alloy conical bushing blank is 10 seconds to 20 seconds.

[0075] 7) After heat treatment, the medium entropy alloy conical bushing blank is finely machined to remove a small amount of excess. After testing, the density is 12.8g / cm 3 , medium entropy alloy tapered bushing B with an elongation of 65%. Example 3

[0076] This embodiment aims to prepare a certain type of medium entropy alloy conical bushing C, and the detailed preparation process is as follows:

[0077] 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%, with the balance being Ni and unavoidable impurities. The medium-entropy alloy melt is cast into an electrode using vacuum induction melting technology, and the electrode is further subjected to vacuum consumable arc melting to obtain a medium-entropy alloy ingot.

[0078] 2) Processing the obtained medium-entropy alloy ingot into a plasma rotating electrode to prepare medium-entropy alloy plasma rotating electrode powder.

[0079] Among them: coarse powder with a particle size of 75μm to 300μm accounts for 60% by mass, and the rest is fine powder, and the particle size of the fine powder is 15μm to 53μm.

[0080] 3) The medium entropy alloy plasma rotating electrode powder is loaded into a pre-designed and processed control bag. After it is filled and vibrated, the control bag is heated and degassed. Specifically, the temperature is first increased from room temperature to 150°C at a heating rate of 10°C / min and then kept at this temperature for 150 minutes; then the temperature is increased to 330°C at a heating rate of 10°C / min and then kept at this temperature for 150 minutes; finally, the temperature is increased to 530°C at a heating rate of 8°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.

[0081] 4) The shape-controlling sleeve after sealing and welding is subjected to hot isostatic pressing treatment. Specifically, the temperature is first increased to 1000°C at a heating rate of 15°C / min and then kept at this temperature for 60 minutes, while the pressure is increased to 150 MPa; then the temperature is increased to 1350°C at a heating rate of 13°C / min and kept at this temperature for 120 minutes to obtain a hot isostatically pressed billet.

[0082] 5) After the hot isostatically pressed blank is pickled to remove the external shape-controlling sheath, a medium-entropy alloy tapered bushing blank is obtained. The pickling process for removing the shape-controlling sheath is performed using a composite acid consisting of sulfuric acid and phosphoric acid. The sulfuric acid has a mass fraction of 66% and a concentration of 17%, while the remainder is phosphoric acid, with a concentration of 5%.

[0083] 6) First, the medium-entropy alloy conical bushing blank is placed in a 1450°C heat treatment furnace for 2 hours of solution treatment; after the solution treatment is completed, the medium-entropy alloy conical bushing blank is water-cooled quenched, and the transfer time from the solution treatment to the water-cooled quenching treatment of the medium-entropy alloy conical bushing blank is 10s to 20s.

[0084] 7) After heat treatment, the medium entropy alloy conical bushing blank is finely machined to remove a small amount of excess. After testing, the density is 11.65g / cm 3 , medium entropy alloy tapered bushing C with an elongation of 70%.

[0085] Example 4

[0086] This embodiment aims to prepare a certain type of medium entropy alloy conical bushing D, and the detailed preparation process is as follows:

[0087] 1) The mass percentages of the main components of the medium-entropy alloy are as follows: W 25%, Co 17%, Mo 10%, and the balance is Ni and inevitable impurities. The medium-entropy alloy melt is cast into an electrode using vacuum induction melting technology, and the electrode is further subjected to vacuum consumable arc melting to obtain a medium-entropy alloy ingot.

[0088] 2) Processing the obtained medium-entropy alloy ingot into a plasma rotating electrode to prepare medium-entropy alloy plasma rotating electrode powder.

[0089] Among them: coarse powder with a particle size of 75μm to 300μm accounts for 70% by mass, and the rest is fine powder, and the particle size of the fine powder is 15μm to 53μm.

[0090] 3) The medium entropy alloy plasma rotating electrode powder is loaded into a pre-designed and processed control bag. After it is filled and vibrated, the control bag is heated and degassed. Specifically, the temperature is first increased from room temperature to 200°C at a heating rate of 10°C / min and then kept at this temperature for 30 minutes; then the temperature is increased to 250°C at a heating rate of 10°C / min and then kept at this temperature for 240 minutes; finally, the temperature is increased to 500°C at a heating rate of 10°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.

[0091] 4) The shape-controlling sleeve after sealing and welding is subjected to hot isostatic pressing treatment. Specifically, the temperature is first increased to 1050°C at a heating rate of 14°C / min and then kept at this temperature for 60 minutes, while the pressure is increased to 150 MPa; then the temperature is increased to 1300°C at a heating rate of 14°C / min and kept at this temperature for 120 minutes to obtain a hot isostatically pressed billet.

[0092] 5) After the hot isostatically pressed blank is pickled to remove the external shape-controlling sheath, a medium-entropy alloy tapered bushing blank is obtained. The pickling process for removing the shape-controlling sheath is performed using a composite acid consisting of sulfuric acid and phosphoric acid. The sulfuric acid has a mass fraction of 50% and a concentration of 20%, while the remainder is phosphoric acid at a concentration of 10%.

[0093] 6) First, the medium-entropy alloy conical bushing blank is placed in a 1350°C heat treatment furnace for 2.2 hours of solution treatment; after the solution treatment is completed, the medium-entropy alloy conical bushing blank is water-cooled quenched, and the transfer time from the solution treatment to the water-cooled quenching treatment of the medium-entropy alloy conical bushing blank is 10 seconds to 20 seconds.

[0094] 7) After heat treatment, the medium entropy alloy conical bushing blank is finely machined to remove a small amount of excess. After testing, the density is 12.0g / cm 3 , medium entropy alloy tapered bushing D with an elongation of 68%.

[0095] Comparative Examples 1-2

[0096] The present invention is based on Examples 1 and 2 of the application No. 202110182870.5 filed by Beijing Institute of Technology on February 10, 2021, entitled "A method for preparing a medium-density ultra-high plasticity nickel-tungsten alloy liner material," as comparative examples 1 and 2, respectively.

[0097] The properties of the final products obtained in Examples 1 to 4 of the present invention and Comparative Examples 1 to 2 are shown in Table 1 below:

[0098] Table 1 Performance test results of the parts obtained from Examples 1 to 4 of the present invention and Comparative Examples 1 to 2

[0099]

[0100] The test results in Table 1 show that the medium entropy alloy conical bushings prepared in Examples 1 to 4 of the present invention have better plasticity (elongation ≥ 65%) and density (density ≥ 11.5 g / cm 3 ). This is because the present invention innovatively adopts powder hot isostatic pressing to prepare medium-entropy alloy conical bushings, and this preparation method has significant advantages. In the traditional preparation process, the segregation problem of high-melting-point tungsten in nickel is more difficult, which seriously affects the performance and quality of the alloy. The present invention uses powder hot isostatic pressing technology to suppress this segregation phenomenon to the greatest extent. By precisely controlling the process parameters, the tungsten element is evenly distributed in the alloy, thereby greatly increasing the tungsten content in the alloy. The higher and more uniform tungsten content not only improves the density of the alloy, but also plays a key optimization role in the overall performance. In addition, the traditional process often requires the introduction of a high-temperature homogenization process during the forming process, which not only consumes a lot of time and energy, but also lengthens the production cycle and increases production costs. The present invention directly completes near-net forming through powder hot isostatic pressing, which not only shortens the production process, but also improves material utilization. This efficient, energy-saving and high-performance preparation technology for parts has undoubtedly laid a solid foundation for the large-scale production and wide application of medium-entropy alloy conical bushings.

[0101] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0102] It should be understood that the present invention is not limited to the above description and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only 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 melt of a medium-entropy alloy with a specific composition to form an electrode, and then subjecting the electrode to vacuum consumable arc melting treatment 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. After the powder is fully loaded and vibrated, the shape-controlling sleeve is first heated and degassed until the vacuum degree requirement is met, and then the shape-controlling sleeve is sealed and welded; Step 4: hot isostatic pressing 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 isostatically pressed blank by pickling or machining, a medium-entropy alloy conical bushing blank is obtained, and then 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; In step 1, the main components of the medium-entropy alloy and the mass fractions of each component are as follows: W: 15% to 47%, Co: 0 to 20%, Mo: 0 to 20%, Ta: 0 to 20%, La: 0 to 20%, and the balance is Ni; wherein Ni and W are essential elements, and the remaining elements include at least two of Co, Mo, Ta, and La; In step 2, the medium entropy alloy plasma rotating electrode powder adopts a bimodal distribution of fine powder and coarse powder; wherein 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; In step 4, the specific process of the hot isostatic pressing treatment is as follows: 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 at this temperature for 30 min to 120 min, while the pressure is raised to 120 MPa to 180 MPa; 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 at this temperature for 60 min to 240 min; In step 5, the heat treatment process is as follows: 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 subjected to water-cooling quenching treatment, and the transfer time of the medium-entropy alloy conical bushing blank from solution treatment to water-cooling quenching treatment should be less than 30s.

2. The method for preparing the ultra-high 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.

3. 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, increase the temperature from room temperature to 100°C to 200°C at a heating rate of 5°C / min to 20°C / min, and then keep it warm for 30min to 240min; then increase the temperature to 250°C to 400°C at a heating rate of 5°C / min to 20°C / min, and then keep it warm for 30min to 240min; finally, increase the temperature to 450°C to 600°C at a heating rate of 5°C / min to 20°C / min, and then keep it warm until the vacuum degree is less than 1.0×10 -4 Pa's request.

4. The method for preparing the ultra-high 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%.

5. 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 4, and the density of the medium entropy alloy conical bushing is ≥11.5g / cm 3 , elongation ≥65%.

6. An application of the ultra-high plasticity medium entropy alloy tapered bushing as claimed in claim 5, 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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