As-cast single-phase bcc refractory high-entropy alloy with matching strength and plasticity and preparation method thereof

Abstract

This invention relates to a refractory high-entropy alloy with a strong-plasticity match in the as-cast state and its preparation method. The purpose of this invention is to solve the problem of the mismatch between strength and plasticity in existing as-cast refractory high-entropy alloys. The as-cast refractory high-entropy alloy of this invention is composed of 16.67%–33.33% Ti, 16.67%–20% Zr, 16.67%–20% Nb, 16.67%–20% Hf, and 3%–16.67% V by atomic percentage. The prepared refractory high-entropy alloys all possess a stable single-phase BCC structure. The as-cast microstructure of the refractory high-entropy alloy can achieve a compressive yield strength of up to 1008 MPa at room temperature, with compressive strains all exceeding 50%. This invention has applications in the preparation of refractory high-entropy alloys.

Description

Technical Field

[0001] This invention relates to a single-phase BCC refractory high-entropy alloy with strength and plasticity matching in the as-cast state and its preparation method. Background Technology

[0002] With the continuous development of human society, various fields are placing increasingly higher demands on the service environment and performance of materials. Unlike traditional alloys that use a single element as the main component, high-entropy alloys employ multiple elements as the main components in their design. Since the concept of high-entropy alloys was proposed by Professor Ye Yunwei and Professor Cantor in 2004, a large number of high-entropy alloy materials with excellent properties have been designed, such as high-hardness high-entropy alloys, high-strength high-entropy alloys, and high-entropy alloys with good ductility and toughness.

[0003] High-entropy alloys composed of refractory elements (Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) are called refractory high-entropy alloys (RHEAs). These alloys have a natural advantage in service conditions at ultra-high temperatures (above 1400°C). Refractory high-entropy alloys still exhibit good yield strength at ultra-high temperatures. However, they suffer from poor room-temperature plasticity, which limits their industrial applications. Improving their room-temperature plasticity, on the other hand, affects their strength. Therefore, how to balance strength and plasticity, and continuously improve the strength of refractory high-entropy alloys while ensuring their excellent plasticity, has become an urgent problem to be solved in the field of refractory high-entropy alloys. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that existing refractory high-entropy alloys cannot simultaneously achieve both strength and plasticity, and to propose a single-phase BCC refractory high-entropy alloy with a strong-plasticity balance in the as-cast state and its preparation method.

[0005] This invention discloses a single-phase BCC refractory high-entropy alloy with strong-ductility matching in the as-cast state, which is composed of 16.67%–33.33% Ti, 16.67%–20% Zr, 16.67%–20% Nb, 16.67%–20% Hf and 3%–16.67% V by atomic percentage, and the sum of the atomic percentages of each component is 100%.

[0006] A method for preparing a single-phase BCC refractory high-entropy alloy with strong-ductility matching in the as-cast state, comprising the following steps:

[0007] 1. Weigh the raw materials according to the stated atomic percentage;

[0008] 2. Pre-treat the raw materials and titanium blocks, then add the raw materials to the crucible of the melting furnace in the order of Nb, Hf, V, Zr and Ti from bottom to top. Then add 50-70g of titanium blocks to another crucible of the melting furnace. After evacuating the melting furnace, fill it with argon gas for protective melting. Melt the titanium blocks first, then melt the raw materials. After cooling, obtain the button ingot sample.

[0009] 3. The alloy ingot is repeatedly melted 7-10 times and cooled to obtain a single-phase BCC refractory high-entropy alloy with strong and ductile properties in the as-cast state.

[0010] The present invention has the following gain effects:

[0011] I. This invention provides a refractory high-entropy alloy with strong and ductile properties. The elements Ti, Zr, Nb, Hf, and V, and their relative contents, are selected in this invention because these five elements can form a single-phase refractory high-entropy alloy (BCC), which has a simple structure. In this invention, the atomic radius of V is 132 pm, lower than that of Ti, Zr, Nb, and Hf. Therefore, the addition of V increases the degree of lattice distortion, making the solid solution strengthening and grain refinement effects of the alloy more significant, thereby improving the overall mechanical properties of the alloy.

[0012] II. This invention first selects a matrix component with a high Ti content, Ti. 40 Zr 20 Nb 20 Hf 20 The matrix exhibits excellent compressive strain rate but low compressive yield strength. Therefore, this invention leverages the strengthening effect of V by varying its addition amount. When 16.67 at.% V is added, the room temperature compressive strength of the alloy can be increased from 613 MPa to 1008 MPa while maintaining a compressive strain rate of over 50%.

[0013] Third, the alloy prepared by the method of the present invention is melted and solidified in a water-cooled copper crucible, which is low in cost, simple and easy to implement, does not require subsequent heat treatment and hot deformation optimization, has a short preparation cycle, and the microstructure obtained after solidification is uniform and has a single solid solution microstructure.

[0014] This invention aims to improve strength while ensuring a suitable balance of plasticity, and proposes a Ti material that combines both strength and plasticity. a Zr b Nb c Hf d V e Methods for controlling the mechanical properties of refractory high-entropy alloys. By changing the amount of V added, mechanical properties can be improved, providing new insights for further exploration of refractory high-entropy alloy systems. Attached Figure Description

[0015] Figure 1 XRD patterns of refractory high-entropy alloys prepared in Examples 1 to 5 and Comparative Example 1;

[0016] Figure 2 SEM image of the refractory high-entropy alloy prepared in Example 2;

[0017] Figure 3 Metallographic image of the refractory high-entropy alloy prepared in Example 2;

[0018] Figure 4 The compressive stress-strain curves of the high-entropy alloys prepared in Examples 1 to 5 and Comparative Example 1 are shown. Detailed Implementation

[0019] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0020] Specific Implementation Method 1: This implementation method describes a single-phase BCC refractory high-entropy alloy with strong and ductile properties in the as-cast state, which is composed of 16.67%–33.33% Ti, 16.67%–20% Zr, 16.67%–20% Nb, 16.67%–20% Hf, and 3%–16.67% V by atomic percentage, with the sum of the atomic percentages of each component being 100%.

[0021] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the alloy is composed of 38.46% Ti, 19.23% Zr, 19.23% Nb, 19.23% Hf, and 3.85% V by atomic percentage, expressed as Ti 38.46 Zr 19.23 Nb 19.23 Hf 19.23 V 3.85 Everything else is the same as in Specific Implementation Method 1.

[0022] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the alloy is composed of 37.04% Ti, 18.52% Zr, 18.52% Nb, 18.52% Hf, and 7.40% V by atomic percentage, expressed as Ti 37.04 Zr 18.52 Nb 18.52 Hf 18.52 V 7.40 Everything else is the same as in specific implementation method one or two.

[0023] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the alloy is composed of 35.71% Ti, 17.86% Zr, 17.86% Nb, 17.86% Hf, and 10.71% V by atomic percentage, expressed as Ti35.7 1Zr 17.86 Nb 17.86 Hf 17.86 V 10.71 Everything else is the same as in any of the specific implementation methods one to three.

[0024] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the alloy is composed of 34.48% Ti, 17.24% Zr, 17.24% Nb, 17.24% Hf, and 13.80% V by atomic percentage, denoted as Ti. 34.48 Zr 17.24 Nb 17.24 Hf 17.24 V 13.80 Everything else is the same as in any of the specific implementation methods one to four.

[0025] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the alloy is composed of 33.32% Ti, 16.67% Zr, 16.67% Nb, 16.67% Hf, and 16.67% V by atomic percentage, expressed as Ti 33.3 2Zr 16.67 Nb 16.67 Hf 16.67 V 16.67 Everything else is the same as in any one of the specific implementation methods one to five.

[0026] Specific Implementation Method Seven: This implementation method describes a method for preparing a single-phase BCC refractory high-entropy alloy with a strong-ductility matching in the as-cast state, which is carried out according to the following steps:

[0027] 1. Weigh the raw materials according to the stated atomic percentage;

[0028] 2. Pre-treat the raw materials and titanium blocks, then add the raw materials to the crucible of the melting furnace in the order of Nb, Hf, V, Zr and Ti from bottom to top. Then add 50-70g of titanium blocks to another crucible of the melting furnace. After evacuating the melting furnace, fill it with argon gas for protective melting. Melt the titanium blocks first, then melt the raw materials. After cooling, obtain the button ingot sample.

[0029] 3. The alloy ingot is repeatedly melted 7-10 times and cooled to obtain a single-phase BCC refractory high-entropy alloy with strong and ductile properties in the as-cast state.

[0030] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that the pretreatment in step two involves grinding, polishing, cleaning, and then drying. Everything else is the same as in Specific Implementation Method Seven.

[0031] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Seven or Eight in that: Step Two involves evacuating the furnace to achieve a vacuum level of 3 × 10⁻⁶.-3 Pa, then high-purity argon gas is introduced as a protective gas to 0.05 MPa. Everything else is the same as in specific embodiments seven or eight.

[0032] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Seven to Nine in that the current intensity during smelting is 300-600A. Everything else is the same as in Specific Implementation Methods Seven to Nine.

[0033] The beneficial effects of the present invention are verified using the following embodiments:

[0034] Example 1: A single-phase BCC refractory high-entropy alloy with strong-ductility matching in the as-cast state, composed of 38.46% Ti, 19.23% Zr, 19.23% Nb, 19.23% Hf and 3.85% V by atomic percentage, denoted as Ti. 38.46 Zr 19.23 Nb 19.23 Hf 19.23 V 3.85 ;

[0035] Its preparation method is as follows:

[0036] (1) Weigh Ti blocks, Zr blocks, Nb particles, Hf particles and V particles according to the above atomic ratio to obtain raw materials; the purity of the raw materials is greater than 99.95%.

[0037] (2) The selected raw materials and titanium blocks are pre-treated by grinding and cleaning to remove oxides and impurities from the surface of the raw materials. The oxide scale is removed by grinding with 400-mesh SiC sandpaper. Acetone is used as the cleaning agent for ultrasonic cleaning for 8 minutes. The ultrasonic power is 100W and the frequency is 25KHz. The raw materials and titanium blocks after acetone cleaning are then ultrasonically cleaned a second time with anhydrous ethanol as the cleaning agent for 5 minutes. The ultrasonic power is 120W and the frequency is 35KHz. The sample surface is then dried with a blower.

[0038] (3) The processed raw materials are placed into the crucible of the non-consumable vacuum arc furnace in the order of Nb, Hf, V, Zr, and Ti. At the same time, the titanium metal block is placed into another crucible of the non-consumable vacuum arc furnace and evacuated to a vacuum level of 3×10. -3 Pa, high-purity argon gas is introduced to a protective pressure of 0.05 MPa, vacuum is repeatedly evacuated and purged with argon gas, and the gas is washed 3 times. Then, arc melting is carried out. First, the titanium block is melted at a melting current of 450 A for 3 min. During the melting process, the residual oxygen in the electric arc furnace chamber is adsorbed, further reducing the oxidation behavior during the melting process. Then, the alloy ingot is melted at a melting current of 600 A for 5 min. After cooling, the initial melted alloy ingot is obtained.

[0039] (4) The initial melted alloy ingot is flipped using the furnace's built-in robotic arm. After flipping, it is melted again. This process is repeated 7 times. The alloy needs to be flipped each time to ensure the uniformity of the alloy composition. After multiple melting processes, the ingot is cooled to obtain Ti. 38.46 Zr 19.23 Nb 19.23 Hf 19.23 V 3.85 Refractory high-entropy alloys.

[0040] Example 2: A single-phase BCC refractory high-entropy alloy with strength and ductility matching in the as-cast state, composed of 37.04% Ti, 18.52% Zr, 18.52% Nb, 18.52% Hf and 7.40% V by atomic percentage, denoted as Ti. 37.04 Zr 18.52 Nb 18.52 Hf 18.52 V 7.40 ;

[0041] Its preparation method is as follows:

[0042] (1) Weigh Ti blocks, Zr blocks, Nb particles, Hf particles and V particles according to the above atomic ratio to obtain raw materials; the purity of the raw materials is greater than 99.95%.

[0043] (2) The selected raw materials and titanium blocks are pre-treated by grinding and cleaning to remove oxides and impurities from the surface of the raw materials. The oxide scale is removed by grinding with 400-mesh SiC sandpaper. Acetone is used as the cleaning agent for ultrasonic cleaning for 8 minutes. The ultrasonic power is 100W and the frequency is 25KHz. The raw materials and titanium blocks after acetone cleaning are then ultrasonically cleaned a second time with anhydrous ethanol as the cleaning agent for 5 minutes. The ultrasonic power is 120W and the frequency is 35KHz. The sample surface is then dried with a blower.

[0044] (3) The processed raw materials are placed into the crucible of the non-consumable vacuum arc furnace in the order of Nb, Hf, V, Zr, and Ti. At the same time, the titanium metal block is placed into another crucible of the non-consumable vacuum arc furnace and evacuated to a vacuum level of 3×10. -3 Pa, high-purity argon gas is introduced to a protective pressure of 0.05 MPa, vacuum is repeatedly evacuated and purged with argon gas, and the gas is washed 3 times. Then, arc melting is carried out. First, the titanium block is melted at a melting current of 450 A for 3 min. During the melting process, the residual oxygen in the electric arc furnace chamber is adsorbed, further reducing the oxidation behavior during the melting process. Then, the alloy ingot is melted at a melting current of 600 A for 5 min. After cooling, the initial melted alloy ingot is obtained.

[0045] (4) The initial melted alloy ingot is flipped using the furnace's built-in robotic arm. After flipping, it is melted again. This process is repeated 7 times. The alloy needs to be flipped each time to ensure the uniformity of the alloy composition. After multiple melting processes, the ingot is cooled to obtain Ti. 37.04 Zr 18.52 Nb 18.52 Hf 18.52 V 7.40 Refractory high-entropy alloys.

[0046] Example 3: A single-phase BCC refractory high-entropy alloy with strong-ductility matching in the as-cast state, composed of 35.71% Ti, 17.86% Zr, 17.86% Nb, 17.86% Hf and 10.71% V by atomic percentage, denoted as Ti. 35.71 Zr 17.86 Nb 17.86 Hf 17.86 V 10.71 ;

[0047] Its preparation method is as follows:

[0048] (1) Weigh Ti blocks, Zr blocks, Nb particles, Hf particles and V particles according to the above atomic ratio to obtain raw materials; the purity of the raw materials is greater than 99.95%.

[0049] (2) The selected raw materials and titanium blocks are pre-treated by grinding and cleaning to remove oxides and impurities from the surface of the raw materials. The oxide scale is removed by grinding with 400-mesh SiC sandpaper. Acetone is used as the cleaning agent for ultrasonic cleaning for 8 minutes. The ultrasonic power is 100W and the frequency is 25KHz. The raw materials and titanium blocks after acetone cleaning are then ultrasonically cleaned a second time with anhydrous ethanol as the cleaning agent for 5 minutes. The ultrasonic power is 120W and the frequency is 35KHz. The sample surface is then dried with a blower.

[0050] (3) The processed raw materials are placed into the crucible of the non-consumable vacuum arc furnace in the order of Nb, Hf, V, Zr, and Ti. At the same time, the titanium metal block is placed into another crucible of the non-consumable vacuum arc furnace and evacuated to a vacuum level of 3×10. -3 Pa, high-purity argon gas is introduced to a protective pressure of 0.05 MPa, vacuum is repeatedly evacuated and purged with argon gas, and the gas is washed 3 times. Then, arc melting is carried out. First, the titanium block is melted at a melting current of 450 A for 3 min. During the melting process, the residual oxygen in the electric arc furnace chamber is adsorbed, further reducing the oxidation behavior during the melting process. Then, the alloy ingot is melted at a melting current of 600 A for 5 min. After cooling, the initial melted alloy ingot is obtained.

[0051] (4) The initial melted alloy ingot is flipped using the furnace's built-in robotic arm. After flipping, it is melted again. This process is repeated 7 times. The alloy needs to be flipped each time to ensure the uniformity of the alloy composition. After multiple melting processes, the ingot is cooled to obtain Ti. 35.71 Zr 17.86 Nb 17.86 Hf 17.86 V 10.71 Refractory high-entropy alloys.

[0052] Example 4: A single-phase BCC refractory high-entropy alloy with strong-ductility matching in the as-cast state, composed of 34.48% Ti, 17.24% Zr, 17.24% Nb, 17.24% Hf and 13.80% V by atomic percentage, denoted as Ti. 34.48 Zr 17.24 Nb 17.24 Hf 17.24 V 13.80 ;

[0053] Its preparation method is as follows:

[0054] (1) Weigh Ti blocks, Zr blocks, Nb particles, Hf particles and V particles according to the above atomic ratio to obtain raw materials; the purity of the raw materials is greater than 99.95%.

[0055] (2) The selected raw materials and titanium blocks are pretreated by grinding and cleaning to remove oxides and impurities from the surface of the raw materials. The oxide scale is removed by grinding with 400-mesh SiC sandpaper. Acetone is used as the cleaning agent for ultrasonic cleaning for 8 minutes. The ultrasonic power is 100W and the frequency is 25KHz. The raw materials and titanium blocks after acetone cleaning are then ultrasonically cleaned a second time with anhydrous ethanol as the cleaning agent for 5 minutes. The ultrasonic power is 120W and the frequency is 35KHz. The sample surface is then dried with a blower.

[0056] (3) The processed raw materials are placed into the crucible of the non-consumable vacuum arc furnace in the order of Nb, Hf, V, Zr, and Ti. At the same time, the titanium metal block is placed into another crucible of the non-consumable vacuum arc furnace and evacuated to a vacuum level of 3×10. -3 Pa, high-purity argon gas is introduced to a protective pressure of 0.05 MPa, vacuum is repeatedly evacuated and purged with argon gas, and the gas is washed 3 times. Then, arc melting is carried out. First, the titanium block is melted at a melting current of 450 A for 3 min. During the melting process, the residual oxygen in the electric arc furnace chamber is adsorbed, further reducing the oxidation behavior during the melting process. Then, the alloy ingot is melted at a melting current of 600 A for 5 min. After cooling, the initial melted alloy ingot is obtained.

[0057] (4) The initial melted alloy ingot is flipped using the furnace's built-in robotic arm. After flipping, it is melted again. This process is repeated 7 times. The alloy needs to be flipped each time to ensure the uniformity of the alloy composition. After multiple melting processes, the ingot is cooled to obtain Ti. 34.48 Zr 17.24 Nb 17.24 Hf 17.24 V 13.80 Refractory high-entropy alloys.

[0058] Example 5: A single-phase BCC refractory high-entropy alloy with strength and ductility matching in the as-cast state, composed of 33.32% Ti, 16.67% Zr, 16.67% Nb, 16.67% Hf, and 16.67% V by atomic percentage, denoted as Ti. 33.32 Zr 16.67 Nb 16.67 Hf 16.67 V 16.67 ;

[0059] Its preparation method is as follows:

[0060] (1) Weigh Ti blocks, Zr blocks, Nb particles, Hf particles and V particles according to the above atomic ratio to obtain raw materials; the purity of the raw materials is greater than 99.95%.

[0061] (2) The selected raw materials and titanium blocks are pretreated by grinding and cleaning to remove oxides and impurities from the surface of the raw materials. The oxide scale is removed by grinding with 400-mesh SiC sandpaper. Acetone is used as the cleaning agent for ultrasonic cleaning for 8 minutes. The ultrasonic power is 100W and the frequency is 25KHz. The raw materials and titanium blocks after acetone cleaning are then ultrasonically cleaned a second time with anhydrous ethanol as the cleaning agent for 5 minutes. The ultrasonic power is 120W and the frequency is 35KHz. The sample surface is then dried with a blower.

[0062] (3) The processed raw materials are placed into the crucible of the non-consumable vacuum arc furnace in the order of Nb, Hf, V, Zr, and Ti. At the same time, the titanium metal block is placed into another crucible of the non-consumable vacuum arc furnace and evacuated to a vacuum level of 3×10. -3 Pa, high-purity argon gas is introduced to a protective pressure of 0.05 MPa, vacuum is repeatedly evacuated and purged with argon gas, and the gas is washed 3 times. Then, arc melting is carried out. First, the titanium block is melted at a melting current of 450 A for 3 min. During the melting process, the residual oxygen in the electric arc furnace chamber is adsorbed, further reducing the oxidation behavior during the melting process. Then, the alloy ingot is melted at a melting current of 600 A for 5 min. After cooling, the initial melted alloy ingot is obtained.

[0063] (4) The initial melted alloy ingot is flipped using the furnace's built-in robotic arm, and then remelted. This process is repeated 7 times to ensure the uniformity of the alloy composition. After multiple melting processes, the ingot is cooled to obtain Ti. 33.32 Zr 16.67 Nb 16.67 Hf 16.67 V 16.67 Refractory high-entropy alloys.

[0064] Comparative Example 1: This example describes a refractory high-entropy alloy, composed of 40% Ti, 20% Zr, 20% Nb, and 20% Hf by atomic percentage, denoted as Ti. 40 Zr 20 Nb 20 Hf 20 ;

[0065] Its preparation method is as follows:

[0066] (1) Weigh Ti blocks, Zr blocks, Nb particles, and Hf particles according to the above atomic ratio to obtain raw materials; the purity of the raw materials is greater than 99.95%.

[0067] (2) The selected raw materials and titanium blocks are pretreated by grinding and cleaning to remove oxides and impurities from the surface of the raw materials. The oxide scale is removed by grinding with 400-mesh SiC sandpaper. Acetone is used as the cleaning agent for ultrasonic cleaning for 8 minutes. The ultrasonic power is 100W and the frequency is 25KHz. The raw materials and titanium blocks after acetone cleaning are then ultrasonically cleaned a second time with anhydrous ethanol as the cleaning agent for 5 minutes. The ultrasonic power is 120W and the frequency is 35KHz. The sample surface is then dried with a blower.

[0068] (3) The processed raw materials are placed into the crucible of the non-consumable vacuum arc furnace in the order of Nb, Hf, V, Zr, and Ti. At the same time, the titanium metal block is placed into another crucible of the non-consumable vacuum arc furnace and evacuated to a vacuum level of 3×10. -3 Pa, high-purity argon gas is introduced to a protective pressure of 0.05 MPa, vacuum is repeatedly evacuated and purged with argon gas, and the gas is washed 3 times. Then, arc melting is carried out. First, the titanium block is melted at a melting current of 450 A for 3 min. During the melting process, the residual oxygen in the electric arc furnace chamber is adsorbed, further reducing the oxidation behavior during the melting process. Then, the alloy ingot is melted at a melting current of 600 A for 5 min. After cooling, the initial melted alloy ingot is obtained.

[0069] (4) The initial melted alloy ingot is flipped using the furnace's built-in robotic arm, and then remelted. This process is repeated 7 times to ensure the uniformity of the alloy composition. After multiple melting processes, the ingot is cooled to obtain Ti. 40 Zr 20 Nb20 Hf 20 Refractory high-entropy alloys.

[0070] The XRD patterns of the refractory high-entropy alloys of Examples 1 to 5 and Comparative Example 1 are shown below. Figure 1 As shown, the phase structure of the high-entropy alloy was determined using X-ray diffraction. The X-ray source was CuKα (λ = 0.1542 nm) rays, the scanning angle 2θ ranged from 20° to 100°, and the scanning speed was 4° / min. Figure 1 It can be seen that the refractory high-entropy alloys prepared in Examples 1 to 5 and Comparative Example 1 are all single BCC solid solution phase structures without intermetallic compounds. This is because the multi-component characteristics of high-entropy alloys lead to an increased degree of disorder, which increases the mixing entropy of the alloy. The high mixing entropy promotes the compatibility of elements. At the same time, the near-zero mixing enthalpy between elements in this example reduces the bonding force between components, thereby inhibiting the formation of brittle intermetallic compounds and promoting the formation of single-phase solid solutions.

[0071] Ti prepared in Example 2 37.04 Zr 18.52 Nb 18.52 Hf 18.52 V 7.40 Scanning electron microscopy (SEM) microstructure of refractory high-entropy alloys as shown below Figure 2 As shown in the figure, the structure is a single BCC phase, with no other phase structures appearing, and the prepared Ti... 37.04 Zr 18.52 Nb 18.5 2Hf 18.52 V 7.40 The refractory high-entropy alloy has a uniform and fine microstructure, and the uniform BCC single-phase solid solution significantly improves the plasticity of the alloy.

[0072] Ti prepared in Example 2 37.04 Zr 18.52 Nb 18.52 Hf 18.52 V 7.40 Metallographic images of refractory high-entropy alloys, such as Figure 3 As shown in the figure, its microstructure is a typical dendritic and interdendritic structure.

[0073] Table 1. Compression strength and compression deformation at different V contents

[0074]

[0075] The compressive stress and strain of the refractory high-entropy alloys prepared in Examples 1 to 5 are as follows: Figure 4As shown in Table 1, the compressive strength and compressive deformation of the alloy with different V contents are as follows. The room temperature compressive stress-strain curves of the alloy show that with the addition of V, the room temperature compressive strength of the alloy increases from 613 MPa to 1008 MPa; the compressive strain does not decrease with the increase of strength, and the compressive strain is always above 50%. This is mainly due to the combined effect of the atomic structure characteristics of V and its strengthening effect on the alloy. The atomic radius of V is smaller than that of Ti, Zr, Nb, and Hf, while its electronegativity and shear modulus are greater than those of other atoms. These characteristics result in V generating a large lattice distortion energy when dissolved in the alloy, effectively hindering the movement of subsequent dislocations, and its ability to bond with surrounding atoms as a solid-solution atom is stronger.

Claims

1. A single-phase BCC refractory high-entropy alloy with strength-ductility matching in the as-cast state, characterized in that... This refractory high-entropy alloy is Ti. 37.0 4Zr 18.52 Nb 18.52 Hf 18.52 V 7.40 Ti 35.71 Zr 17.86 Nb 17.86 Hf 17.86 V 10.71 Ti 34.48 Zr 17.24 Nb 17.24 Hf 17.24 V 13.80 or Ti 33.32 Zr 16.67 Nb 16.67 Hf 16.67 V 16.67 ; among which Ti 37.04 Zr 18.52 Nb 18.52 Hf 18.52 V 7.40 It is composed of 37.04% Ti, 18.52% Zr, 18.52% Nb, 18.52% Hf and 7.40% V by atomic percentage; Ti 35.71 Zr 17.86 Nb 17.86 Hf 17.86 V 10.71 It is composed of 35.71% Ti, 17.86% Zr, 17.86% Nb, 17.86% Hf and 10.71% V by atomic percentage; Ti 34.48 Zr 17.24 Nb 17.24 Hf 17.2 4V 13.80 It is composed of 34.48% Ti, 17.24% Zr, 17.24% Nb, 17.24% Hf and 13.80% V by atomic percentage; Ti 33.32 Zr 16.67 Nb 16.67 Hf 16.67 V 16.67 It consists of 33.32% Ti, 16.67% Zr, 16.67% Nb, 16.67% Hf and 16.67% V by atomic percentage; The preparation method of the refractory high-entropy alloy is as follows:

1. Weigh the raw materials according to the stated atomic percentage; 2. Pre-treat the raw materials and titanium blocks, then add the raw materials to the crucible of the melting furnace in the order of Nb, Hf, V, Zr and Ti from bottom to top. Then add 50-70g of titanium blocks to another crucible of the melting furnace. After evacuating the melting furnace, fill it with argon gas for protective melting. Melt the titanium blocks first, then melt the raw materials. After cooling, obtain the button ingot sample.

3. The alloy ingot is repeatedly melted 7-10 times and cooled to obtain a single-phase BCC refractory high-entropy alloy with strong and ductile properties in the as-cast state.

2. The method for preparing a single-phase BCC refractory high-entropy alloy with strength-ductility matching in the as-cast state as described in claim 1, characterized in that, The preparation method is carried out according to the following steps:

1. Weigh the raw materials according to the stated atomic percentage; 2. Pre-treat the raw materials and titanium blocks, then add the raw materials to the crucible of the melting furnace in the order of Nb, Hf, V, Zr and Ti from bottom to top. Then add 50-70g of titanium blocks to another crucible of the melting furnace. After evacuating the melting furnace, fill it with argon gas for protective melting. Melt the titanium blocks first, then melt the raw materials. After cooling, obtain the button ingot sample.

3. The alloy ingot is repeatedly melted 7-10 times and cooled to obtain a single-phase BCC refractory high-entropy alloy with strong and ductile properties in the as-cast state.

3. The method for preparing a single-phase BCC refractory high-entropy alloy with strength-ductility matching in the as-cast state according to claim 2, characterized in that, The pretreatment in step two involves grinding and polishing, cleaning, and then drying.

4. The method for preparing a single-phase BCC refractory high-entropy alloy with strength-ductility matching in the as-cast state according to claim 2, characterized in that, Step 2: Vacuuming to achieve a vacuum level of 3 × 10⁻⁶ inside the furnace. -3 Pa, then high-purity argon gas is introduced as a protective gas to 0.05 MPa.

5. The method for preparing a single-phase BCC refractory high-entropy alloy with strength-ductility matching in the as-cast state according to claim 2, characterized in that, The current intensity during smelting is 300-600A.

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