Preparation method of high-entropy alloy with constant and super-elastic properties, alloy and application

Abstract

A preparation method of a high-entropy alloy with constant elasticity and super-elasticity, the alloy and applications, the method comprises the following steps: Ti, Zr, Hf, Ta and Nb are melted to obtain an alloy ingot of Ti a Zr b Hf c Ta d Nb e , wherein a, b, c, d and e are atomic percentages of the five elements, a is 25-30, b is 25-30, c is 25-30, d is 5-15 and e is 4-8, and a+b+c+d+e=100; and the alloy ingot is hot forged to obtain the high-entropy alloy. The high-entropy alloy has constant elasticity and super-elasticity and excellent mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of alloy materials technology, and in particular to a method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, as well as the alloy and its applications. Background Technology

[0002] Constant-elastic and hyperelastic alloys, as core functional materials in high-end industries, drive innovation in precision manufacturing and extreme-condition technologies, respectively, due to their advantages in modulus temperature stability and ultra-large recoverable strain. Constant-elastic alloys, by suppressing the influence of temperature changes on modulus, have become key materials for aerospace precision components and complex instruments. Their applications significantly reduce system temperature compensation requirements, overcoming the bottlenecks of complex and costly machining of traditional precision parts. Hyperelastic alloys, relying on their phase transformation-driven large strain recovery capabilities, are widely used in intelligent sensing, electromechanical automation, and aerospace dynamic components, expanding the extreme applications of functional materials.

[0003] However, mainstream hyperelastic alloys rely on martensitic phase transformation to achieve hyperelasticity, and their modulus fluctuates drastically during the phase transformation, which fundamentally conflicts with the requirement of constant modulus in constant elastic alloys. For example, invention patent CN118028658 A discloses a hyperelastic low-modulus TiZrNbSn alloy and its preparation method, which has significant hyperelasticity and low modulus characteristics, but it does not possess constant elasticity; invention patent CN114369744 A discloses a non-magnetic wide-temperature-range constant elastic titanium alloy and its preparation method, which has wide-temperature-range constant elasticity and excellent comprehensive mechanical properties, but it does not possess hyperelasticity, only the linear elasticity of the material itself.

[0004] Unlike traditional alloys with their single principal component systems, high-entropy alloys achieve a single-phase structure with a unique solid solution strengthening mechanism through the atomic-level synergistic effect of multiple components. Their significant high-entropy effect and lattice distortion characteristics not only overcome the traditional inverse relationship between strength and plasticity in alloys, but also open up new paths in the field of functional-structural integration—from achieving synergistic improvement in ultra-high strength and toughness to constructing intelligent material systems that combine mechanical load-bearing capacity with special functional responses. These advancements have been widely applied in the research and development of key aerospace components, precision transmission devices, and bio-implantable devices.

[0005] In recent years, researchers have attempted to introduce the design concept of high-entropy alloys into the development of constant-elastic / hyperelastic materials, trying to achieve dual-functional coupling through compositional entropy regulation. However, existing technologies are limited by key technical bottlenecks such as interface stability control and phase transformation dynamics regulation, making it difficult to establish an effective balance between modulus constancy, hyperelastic strain amplitude, and material strength.

[0006] The information disclosed in the background section is only for enhancing the understanding of the background of this invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] This invention provides a method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, as well as the alloy and its applications. The high-entropy alloy has both constant elasticity and hyperelasticity and excellent mechanical properties.

[0008] A method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity includes:

[0009] Step 1: Ti, Zr, Hf, Ta and Nb are smelted to obtain Ti. a Zr b Hf c Ta d Nb e The alloy ingot, wherein a, b, c, d, and e are the atomic percentages of the five elements, where a = 25~30, b = 25~30, c = 25~30, d = 5~15, e = 4~8, and a+b+c+d+e = 100;

[0010] Step 2: Hot forging the alloy ingot to obtain a high-entropy alloy.

[0011] In the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, in step 1, the purity of Ti, Zr, Hf, Ta and Nb is not less than 99.99%.

[0012] In the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, in step 1, before melting, a vacuum is first drawn and the mixture is purged with an inert gas, followed by evacuation until the gas pressure is less than 1.3 × 10⁻⁶. -3 Pa, with inert gas as the protective gas, the gas pressure during smelting is 0.03~0.06 Pa.

[0013] In the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, in step 1, at the beginning of melting, the heating power of the vacuum induction furnace is adjusted to 50W, and then the power is increased as the required temperature rises, up to a maximum of 100W. During melting, after all components have melted together, the alloy liquid is poured onto a cooling platform to obtain the melted alloy ingot. After melting is completed, the alloy ingot is naturally cooled to room temperature under an inert atmosphere and then taken out.

[0014] In the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, hot forging is performed at 1100℃ in step 2.

[0015] In the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, the engineering thickness reduction rate is 50% in step 2.

[0016] In the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, the balance between constant elasticity and hyperelasticity of the high-entropy alloy is adjusted by regulating the Nb ratio and hot forging parameters.

[0017] A high-entropy alloy is prepared according to the aforementioned method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity.

[0018] The high-entropy alloy described herein has constant elasticity at -150~200℃, recoverable strain of 1.5~2.6%, tensile strength of 0.76~1.1GPa, tensile fracture strain of 5.8~15%, yield strength of 700~850MPa, elastic modulus of 70.2~72.8GPa, and elastic storage density of 2.44~2.63.

[0019] One application of the high-entropy alloy is in aerospace.

[0020] Compared with existing technologies, this invention has the following advantages: the high-entropy alloy possesses both constant elasticity and hyperelasticity, and exhibits excellent mechanical properties. The preparation method of the high-entropy alloy provided by this invention is simple and has a short processing cycle; in particular, the constant elasticity and hyperelasticity of the high-entropy alloy are achieved through elemental control. Attached Figure Description

[0021] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0022] In the attached diagram:

[0023] Figure 1 The static modulus temperature curve of the high-entropy alloy prepared in Example 1 is shown.

[0024] Figure 2 The dynamic modulus-temperature curves of the high-entropy alloys prepared in Examples 1-3 are shown.

[0025] Figure 3 The high-entropy alloy prepared in Example 1 is shown in the room temperature tensile cyclic stress-strain curve.

[0026] Figure 4 The high-entropy alloy prepared in Example 2 is shown in the room temperature tensile cyclic stress-strain curve.

[0027] Figure 5The figure shows the room temperature tensile cyclic stress-strain curve of the high-entropy alloy prepared in Example 3.

[0028] Figure 6 The stress-strain curve of the high-entropy alloy prepared in Example 1 during variable temperature tensile fracture is shown.

[0029] The present invention will be further explained below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0030] Specific embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0031] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0032] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0033] like Figures 1 to 6 As shown, the preparation method of a high-entropy alloy possessing both constant elasticity and hyperelasticity includes the following steps:

[0034] Step 1: Ti, Zr, Hf, Ta and Nb are smelted to obtain Ti. a Zr b Hf c Ta d Nb e The alloy ingot, wherein a, b, c, d, and e are the atomic percentages of the five elements, where a = 25~30, b = 25~30, c = 25~30, d = 5~15, e = 4~8, and a+b+c+d+e = 100;

[0035] Step 2: Hot forging the alloy ingot to obtain a high-entropy alloy.

[0036] In a preferred embodiment of the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, in step 1, the purity of Ti, Zr, Hf, Ta and Nb is not less than 99.99%.

[0037] In a preferred embodiment of the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, in step 1, before melting, a vacuum is first drawn and the mixture is purged with an inert gas, followed by evacuation until the gas pressure is less than 1.3 × 10⁻⁶. -3 Pa, with inert gas as the protective gas, the gas pressure during smelting is 0.03~0.06 Pa.

[0038] In a preferred embodiment of the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, in step 1, at the start of melting, the heating power of the vacuum induction furnace is adjusted to 50W, and then the power is increased as the required temperature rises, up to a maximum of 100W. During melting, after all components have melted together, the molten alloy is poured onto a cooling platform to obtain the molten alloy ingot. After melting is completed, the ingot is naturally cooled to room temperature under an inert atmosphere and then removed.

[0039] In a preferred embodiment of the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, hot forging is performed at 1100°C in step 2.

[0040] In a preferred embodiment of the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, the engineering thickness reduction rate is 50% in step 2.

[0041] In a preferred embodiment of the method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity, the balance between constant elasticity and hyperelasticity of the high-entropy alloy is adjusted by regulating the Nb ratio and hot forging parameters.

[0042] A high-entropy alloy is prepared according to the aforementioned method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity.

[0043] In a preferred embodiment of the high-entropy alloy, the high-entropy alloy has constant elasticity at -150~200℃, recoverable strain of 1.5~2.6%, tensile strength of 0.76~1.1GPa, tensile fracture strain of 5.8~15%, yield strength of 700~850MPa, elastic modulus of 70.2~72.8GPa, and elastic storage density of 2.44~2.63.

[0044] One application of the high-entropy alloy is in aerospace.

[0045] In one embodiment, the martensite size of the high-entropy alloy is at the nanoscale.

[0046] In one embodiment, by finely adjusting the alloy composition to control the martensitic phase transformation process, the transformation of martensite size from the micrometer scale to the nanometer scale was achieved. Specifically, the martensite, ranging from several micrometers to tens of micrometers in traditional hyperelastic alloys, was suppressed to martensite domains of tens of nanometers, and the average structure did not exhibit a martensitic phase transformation. This microscopic structural transformation effect had a decisive impact on the macroscopic properties of the material: it not only changed the rate of change of the elastic modulus with temperature, achieving a constant elasticity effect, but also endowed the high-entropy alloy with hyperelasticity due to the inherent characteristics of nanoscale martensite. Through the selection of numerous elements, the inventors specifically set five components: Ti, Zr, Hf, Ta, and Nb, ultimately obtaining a high-entropy alloy that possesses both constant elasticity and hyperelasticity characteristics. The inventors discovered that by adjusting the proportion of Nb, the constant elasticity effect can be effectively improved, allowing the high-entropy alloy to ultimately exhibit both properties. Furthermore, considering the influence of lattice defects and point defects on material properties, a balance between constant elasticity and hyperelasticity was achieved in the high-entropy alloy system by adjusting the proportion of Nb and hot forging.

[0047] In one embodiment, since the vacuum induction furnace is a vacuum environment, it effectively isolates oxygen, nitrogen, and other gaseous contaminants, significantly reducing oxidation and impurity inclusions during the metal smelting process. Furthermore, electromagnetic induction heating enables rapid melting and uniform stirring. Combined with precise atmosphere control of the vacuum system, it ensures efficient melting of alloying elements and uniform composition. Therefore, vacuum induction melting is preferred. In step 2, the post-processing includes hot forging at 1100°C, with a thickness reduction rate of 50%. In this invention, at a high temperature of 1100°C, the raw material is above its recrystallization temperature, enhancing atomic diffusion and accelerating the dynamic recrystallization process. This significantly reduces deformation resistance to only 1 / 10 to 1 / 5 of that at room temperature, facilitating plastic flow and preventing work hardening. This large plastic deformation of 50% thickness reduction is achieved through multi-pass forging or high-tonnage equipment. Its purpose is to optimize the material's microstructure—refining the grain size, such as from coarse casting grains to tens of micrometers, following the Hall-Petch relationship, improving strength, eliminating defects such as porosity / shrinkage, and improving metal flow distribution, while simultaneously meeting shape requirements and economic efficiency.

[0048] High-entropy alloy is Ti a Zr b Hf c Ta d Nb e The alloy is composed of five elements: Ti, Zr, Hf, Ta, and Nb, where a, b, c, d, and e are the atomic percentages of the five elements, where a = 25-30, b = 25-30, c = 25-30, d = 5-15, and e = 4-8, and a+b+c+d+e = 100. Preferably, the high-entropy alloy is Ti. a Zr b Hf cTa d Nb e The alloy is composed of five elements: Ti, Zr, Hf, Ta, and Nb. a, b, c, d, and e are the atomic percentages of the five elements, where a = 28.4, b = 28.4, c = 28.4, d = 8.8, e = 6, and a + b + c + d + e = 100.

[0049] In this invention, the high-entropy alloy has constant elasticity at -150~200℃; the high recoverable strain is 1.5~2.6%; the high-entropy alloy has a tensile strength of 0.76~1.1GPa, a tensile fracture strain of 5.8~15%, a yield strength of 700~850MPa, an elastic modulus of 70.2~72.8GPa, and an elastic storage density of 2.44~2.63.

[0050] On the other hand, according to the method for preparing the high-entropy alloy according to the first aspect of the present invention, the method includes:

[0051] Step 1: Ti, Zr, Hf, Ta and Nb are smelted to obtain an alloy ingot;

[0052] Step 2: The alloy ingot is post-processed to obtain the high-entropy alloy.

[0053] In step 1, calculate Ti a Zr b Hf c Ta d Nb e The alloy is composed of five elements: Ti, Zr, Hf, Ta, and Nb, where a, b, c, d, and e are the atomic percentages of the five elements, where a = 25-30, b = 25-30, c = 25-30, d = 5-15, and e = 4-8, and a+b+c+d+e = 100. Preferably, the high-entropy alloy is Ti. a Zr b Hf c Ta d Nb e The alloy is composed of five elements: Ti, Zr, Hf, Ta, and Nb. a, b, c, d, and e are the atomic percentages of the five elements, where a = 28.4, b = 28.4, c = 28.4, d = 8.8, e = 6, and a + b + c + d + e = 100.

[0054] In step 1, the purity of Ti, Zr, Hf, Ta and Nb is not less than 99.99%.

[0055] In step 1, the crucible used to hold the sample needs to be placed in a muffle furnace, evacuated to negative pressure, heated to 400°C for one hour, and then kept at that temperature for three hours.

[0056] In step 1, before melting, a vacuum is first drawn, and the gas is purged three times with an inert gas such as argon. Then, a vacuum is drawn until the gas pressure is less than 1.3 × 10⁻⁶. -3 Pa.

[0057] In step 1, an inert gas, such as argon, is used as a protective gas, and the gas pressure during melting is maintained at 0.03~0.06 Pa (relative pressure), such as 0.05 Pa. Under a certain gas pressure, the molten metal droplets are less likely to be splashed, which helps to ensure operational safety; the inert gas can also prevent the metal from reacting with oxygen, nitrogen, etc. in the air during the melting process.

[0058] In step 1, at the start of melting, the heating power of the vacuum induction furnace is adjusted to 50W, and then the power is increased as the required temperature rises, up to a maximum of 100W.

[0059] In step 1, during the smelting process, after all the components have melted together, the rocker arm is cranked to pour the molten alloy onto the cooling platform to obtain the smelted alloy ingot.

[0060] In step 1, after melting is completed, the alloy ingot is naturally cooled to room temperature in an inert atmosphere such as argon, and then removed.

[0061] In step 2, the post-processing includes hot forging at 1100°C, with an engineering thickness reduction rate of 50%.

[0062] In order to optimize the material microstructure and improve its uniformity, the raw material was hot-forged at 1100℃. The choice of 1100℃ ensures that the material is fully softened and drives dynamic recrystallization to homogenize the microstructure.

[0063] In step 2, the thickness reduction rate is 50%. An engineering thickness reduction rate of 50% means that the material thickness is reduced from the original value to 50%, such as from 100 mm to 50 mm. A 50% reduction rate achieves performance improvement through sufficient strain accumulation. Example 1

[0064] Ti a Zr b Hf c Ta d Nb e The alloy is composed of five elements: Ti, Zr, Hf, Ta, and Nb. a, b, c, d, and e represent the atomic percentages of the five elements, where a = 25-30, b = 25-30, c = 25-30, d = 5-15, and e = 4-8, with a+b+c+d+e = 100. The following atomic ratio of metal raw materials with a purity of 99.99% or higher is selected: Ti 28.4%, Zr 28.4%, Hf 28.4%, Ta 8.8%, and Nb 6%, with a metal mass of 1 kg, for later use.

[0065] Place the crucible used to hold the sample into a muffle furnace, evacuate to negative pressure, heat to 400°C for one hour, hold for three hours, and then remove it.

[0066] The crucible containing the above-mentioned raw materials was placed inside the large crucible of the vacuum induction furnace. The large dry pot was then placed in the coil of the vacuum induction furnace. A vacuum was then drawn, and the furnace was further purged with argon gas three times. Finally, the furnace was evacuated until the pressure was less than 1.3 × 10⁻⁶. - 3 Pa, at this time, argon gas is introduced as a protective gas to keep the furnace chamber pressure at 0.05Pa; at the beginning of melting, the heating power of the vacuum induction furnace is adjusted to 50W, and then the power is increased as the required temperature rises, up to a maximum of 100W; after all the components are melted together, the rocker is turned to pour the alloy liquid onto the cooling platform to obtain the melted alloy ingot, which is then naturally cooled to room temperature in an inert atmosphere such as argon gas, and the alloy ingot is taken out.

[0067] The alloy is placed in a heating furnace and gradually heated to 1100℃. It is then held at 1100℃ for 2 hours. The alloy heated to 1100℃ is transferred to the press table within 10 seconds using a robotic arm. A hydraulic press is then used with a closed forging die of H13 hot work die steel preheated to 300℃. Water-based graphite lubricant is sprayed on the die to a thickness of 50~100 μm and a pressure of 0.3~0.5MPa. The forging is completed in three passes: the first pass is upsetting using a flat anvil die, pressing down 20% at a speed of 10 mm / s, from 100 mm to 80 mm, at a temperature ≥1050℃; the second pass is pre-forging using a cavity die, pressing down 25% at a depth of 80 mm to 60 mm, holding for 5 seconds, at a temperature ≥1000℃; the third pass is final forging using a precision die, pressing down 15% at a depth of 60 mm to 51 mm, holding for 8 seconds, at a final forging temperature ≥950℃. The flash is then removed by the built-in cutting edge of the mold; within 10 seconds after final forging, the forging is transferred by a robotic arm to a chain plate controlled cooling conveyor line. The cooling method is to turn on the water mist system, with a particle size ≤50 μm and a rate of 150~200℃ / min. After reaching 300℃, the forging is air-cooled. Finally, the forging is left to stand in the drying area to room temperature. During the process, the temperature deviation is monitored by an infrared thermometer for each pass, resulting in a high-entropy alloy, denoted as Nb6 alloy.

[0068] The obtained high-entropy alloy was first wire-cut into 1mm thick sheets, and then tensile specimens with a total length of 40mm, a width of 5mm, and an arc of 0.5mm were wire-cut. The variable-temperature tensile tests were performed at -150℃, -100℃, -50℃, 0℃, 50℃, 100℃, 150℃, and 200℃ using a mechanical testing machine. The resulting static modulus-temperature curves are shown below. Figure 1As shown, the high-entropy alloy obtained under static stress loading exhibits an elastic modulus of 70.2–72.8 GPa and an elastic storage density of 2.44–2.63 kJ / m³ at temperatures ranging from -150°C to 200°C. 3 That is, it exhibits a constant elastic effect within a temperature range of 350℃.

[0069] The obtained high-entropy alloy wire was further cut into cuboids of 25×2.5×1mm, and dynamic modulus was tested on a dynamic thermomechanical analyzer. The obtained dynamic modulus-temperature curve is shown below. Figure 2 As shown in the Nb6 alloy curve, it can be seen that the prepared high-entropy alloy exhibits constant elasticity under stress loading at multiple frequencies, ranging from -150℃ to 200℃, i.e., within a temperature range of 350℃.

[0070] The high-entropy alloy tensile specimens cut above were subjected to room temperature tensile cyclic testing using a mechanical testing machine. The resulting room temperature tensile cyclic stress-strain curves are shown below. Figure 3 As shown, the prepared high-entropy alloy exhibits superelasticity, displaying a recoverable strain of approximately 2.6%.

[0071] The high-entropy alloy tensile specimens cut above were subjected to variable-temperature tensile fracture tests using a mechanical testing machine, and the resulting variable-temperature tensile-compression-compression fracture curves are shown below. Figure 6 As shown, it has a tensile strength of about 800 MPa and a tensile fracture strain of about 10.8% at room temperature. In addition, its yield strength is about 720 MPa and its elastic modulus is about 71 GPa, exhibiting good mechanical properties. Example 2

[0072] Ti a Zr b Hf c Ta d Nb e The alloy is composed of five elements: Ti, Zr, Hf, Ta, and Nb. a, b, c, d, and e represent the atomic percentages of the five elements, where a = 25-30, b = 25-30, c = 25-30, d = 5-15, and e = 4-8, with a+b+c+d+e = 100. The following atomic ratio of metallic raw materials with a purity of 99.99% or higher is selected: Ti 28.4%, Zr 28.4%, Hf 28.4%, Ta 10.8%, and Nb 4%, with a metal mass of 1 kg, for later use.

[0073] Place the crucible used to hold the sample into a muffle furnace, evacuate to negative pressure, heat to 400°C for one hour, hold for three hours, and then remove it.

[0074] The crucible containing the above-mentioned raw materials was placed inside the large crucible of the vacuum induction furnace. The large dry pot was then placed in the coil of the vacuum induction furnace. A vacuum was then drawn, and the furnace was further purged with argon gas three times. Finally, the furnace was evacuated until the pressure was less than 1.3 × 10⁻⁶. - 3 Pa, at this time, argon gas is introduced as a protective gas to keep the furnace chamber pressure at 0.05Pa; at the beginning of melting, the heating power of the vacuum induction furnace is adjusted to 50W, and then the power is increased as the required temperature rises, up to a maximum of 100W; after all the components are melted together, the rocker is turned to pour the alloy liquid onto the cooling platform to obtain the melted alloy ingot, which is then naturally cooled to room temperature in an inert atmosphere such as argon gas, and the alloy ingot is taken out.

[0075] The alloy is placed in a heating furnace and gradually heated to 1100℃. It is then held at 1100℃ for 2 hours. The alloy heated to 1100℃ is transferred to the press table within 10 seconds using a robotic arm. A hydraulic press is then used with a closed forging die of H13 hot work die steel preheated to 300℃. Water-based graphite lubricant is sprayed on the die to a thickness of 50~100 μm and a pressure of 0.3~0.5MPa. The forging is completed in three passes: the first pass is upsetting using a flat anvil die, pressing down 20% at a speed of 10 mm / s, from 100 mm to 80 mm, at a temperature ≥1050℃; the second pass is pre-forging using a cavity die, pressing down 25% at a depth of 80 mm to 60 mm, holding for 5 seconds, at a temperature ≥1000℃; the third pass is final forging using a precision die, pressing down 15% at a depth of 60 mm to 51 mm, holding for 8 seconds, at a final forging temperature ≥950℃. The flash is then removed by the built-in cutting edge of the mold; within 10 seconds after final forging, the forging is transferred by a robotic arm to a chain plate controlled cooling conveyor line. The cooling method is to turn on the water mist system, with a particle size ≤50 μm and a speed of 150~200℃ / min. After reaching 300℃, it is air-cooled. Finally, the forging is left to stand in the drying area to room temperature. During the process, the temperature deviation is monitored by an infrared thermometer for each pass, and a high-entropy alloy is obtained, which is denoted as Nb4 alloy.

[0076] The obtained high-entropy alloy wire was further cut into cuboids of 25×2.5×1mm, and dynamic modulus was tested on a dynamic thermomechanical analyzer. The obtained dynamic modulus-temperature curve is shown below. Figure 2 As shown in the Nb4 alloy curve, it can be seen that the prepared high-entropy alloy exhibits constant elasticity under stress loading at multiple frequencies, ranging from -150℃ to 200℃, i.e., within a temperature range of 350℃.

[0077] The high-entropy alloy tensile specimens cut above were subjected to tensile cyclic testing at room temperature using a mechanical testing machine. The resulting tensile cyclic stress-strain curves at room temperature (℃) are shown below. Figure 4 As shown, the prepared high-entropy alloy exhibits superelasticity, displaying a recoverable strain of approximately 1.5%. Example 3

[0078] Ti a Zr b Hf c Ta d Nb e The alloy is composed of five elements: Ti, Zr, Hf, Ta, and Nb. a, b, c, d, and e represent the atomic percentages of the five elements, where a = 25-30, b = 25-30, c = 25-30, d = 5-15, and e = 4-8, with a+b+c+d+e = 100. The following atomic ratio of metallic raw materials with a purity of 99.99% or higher is selected: Ti 28.4%, Zr 28.4%, Hf 28.4%, Ta 6.8%, and Nb 8%, with a metal mass of 1 kg, for later use.

[0079] Place the crucible used to hold the sample into a muffle furnace, evacuate to negative pressure, heat to 400°C for one hour, hold for three hours, and then remove it.

[0080] The crucible containing the above-mentioned raw materials was placed inside the large crucible of the vacuum induction furnace. The large dry pot was then placed in the coil of the vacuum induction furnace. A vacuum was then drawn, and the furnace was further purged with argon gas three times. Finally, the furnace was evacuated until the pressure was less than 1.3 × 10⁻⁶. - 3 Pa, at this time, argon gas is introduced as a protective gas to keep the furnace chamber pressure at 0.05Pa; at the beginning of melting, the heating power of the vacuum induction furnace is adjusted to 50W, and then the power is increased as the required temperature rises, up to a maximum of 100W; after all the components are melted together, the rocker is turned to pour the alloy liquid onto the cooling platform to obtain the melted alloy ingot, which is then naturally cooled to room temperature in an inert atmosphere such as argon gas, and the alloy ingot is taken out.

[0081] The alloy is placed in a heating furnace and gradually heated to 1100℃. It is then held at 1100℃ for 2 hours. The alloy heated to 1100℃ is transferred to the press table within 10 seconds using a robotic arm. A hydraulic press is then used with a closed forging die of H13 hot work die steel preheated to 300℃. Water-based graphite lubricant is sprayed on the die to a thickness of 50~100 μm and a pressure of 0.3~0.5MPa. The forging is completed in three passes: the first pass is upsetting using a flat anvil die, pressing down 20% at a speed of 10 mm / s, from 100 mm to 80 mm, at a temperature ≥1050℃; the second pass is pre-forging using a cavity die, pressing down 25% at a depth of 80 mm to 60 mm, holding for 5 seconds, at a temperature ≥1000℃; the third pass is final forging using a precision die, pressing down 15% at a depth of 60 mm to 51 mm, holding for 8 seconds, at a final forging temperature ≥950℃. The flash is then removed by the built-in cutting edge of the mold; within 10 seconds after final forging, the forging is transferred by a robotic arm to a chain plate controlled cooling conveyor line. The cooling method is to turn on the water mist system, with a particle size ≤50 μm and a speed of 150~200℃ / min. After reaching 300℃, it is air-cooled. Finally, the forging is left to stand in the drying area to room temperature. During the process, the temperature deviation is monitored by an infrared thermometer for each pass, and a high-entropy alloy is obtained, which is denoted as Nb 8 alloy.

[0082] The obtained high-entropy alloy wire was further cut into cuboids of 25×2.5×1mm, and dynamic modulus was tested on a dynamic thermomechanical analyzer. The obtained dynamic modulus-temperature curve is shown below. Figure 2 As shown in the Nb 8 alloy curve, it can be seen that the prepared high-entropy alloy exhibits constant elasticity under stress loading at multiple frequencies, from -150℃ to 200℃, i.e., within a temperature range of 350℃.

[0083] The high-entropy alloy tensile specimens cut above were subjected to room temperature tensile cyclic testing using a mechanical testing machine. The resulting room temperature tensile cyclic stress-strain curves are shown below. Figure 5 As shown, the prepared high-entropy alloy exhibits superelasticity, displaying approximately 2.2% recoverable strain.

[0084] As can be seen from Examples 1-3, the high-entropy alloy of the present invention has both constant elasticity and hyperelasticity, and has good mechanical properties. The high-entropy alloy in Example 1 has constant elasticity in a temperature range of 350℃ (-150~200℃), that is, it has the widest constant elasticity temperature range, and has the largest recoverable strain, that is, it has the best constant elasticity and hyperelasticity, and has the highest compressive strength, with the best overall performance.

[0085] Comparative Example 1

[0086] High-entropy alloys were prepared in a manner similar to that of Example 1, except that the raw material composition exceeded the aforementioned range, namely:

[0087] Select metal raw materials with a purity of 99.99% or higher and the following atomic ratios: Ti 28.4%, Zr 28.4%, Hf 28.4%, Ta 4.8%, Nb 10%, with a metal mass of 1 kg, for later use;

[0088] Place the crucible used to hold the sample into a muffle furnace, evacuate to negative pressure, heat to 400°C for one hour, hold for three hours, and then remove it.

[0089] The crucible containing the above-mentioned raw materials was placed inside the large crucible of the vacuum induction furnace. The large dry pot was then placed in the coil of the vacuum induction furnace. A vacuum was then drawn, and the furnace was further purged with argon gas three times. Finally, the furnace was evacuated until the pressure was less than 1.3 × 10⁻⁶. - 3 Pa, at this time, argon gas is introduced as a protective gas to keep the furnace chamber pressure at 0.05Pa; at the beginning of melting, the heating power of the vacuum induction furnace is adjusted to 50W, and then the power is increased as the required temperature rises, up to a maximum of 100W; after all the components are melted together, the rocker is turned to pour the alloy liquid onto the cooling platform to obtain the melted alloy ingot, which is then naturally cooled to room temperature in an inert atmosphere such as argon gas, and the alloy ingot is taken out.

[0090] The alloy is placed in a heating furnace and gradually heated to 1100℃. It is then held at 1100℃ for 2 hours. The alloy heated to 1100℃ is transferred to the press table within 10 seconds using a robotic arm. A hydraulic press is then used with a closed forging die of H13 hot work die steel preheated to 300℃. Water-based graphite lubricant is sprayed on the die to a thickness of 50~100 μm and a pressure of 0.3~0.5MPa. The forging is completed in three passes: the first pass is upsetting using a flat anvil die, pressing down 20% at a speed of 10 mm / s, from 100 mm to 80 mm, at a temperature ≥1050℃; the second pass is pre-forging using a cavity die, pressing down 25% at a depth of 80 mm to 60 mm, holding for 5 seconds, at a temperature ≥1000℃; the third pass is final forging using a precision die, pressing down 15% at a depth of 60 mm to 51 mm, holding for 8 seconds, at a final forging temperature ≥950℃. The flash is then removed by the built-in cutting edge of the mold; within 10 seconds after final forging, the forging is transferred by a robotic arm to a chain plate controlled cooling conveyor line. The cooling method is to turn on the water mist system, with a particle size ≤50 μm and a speed of 150~200℃ / min. After reaching 300℃, the forging is air-cooled. Finally, the forging is left to stand in the drying area to room temperature. During the process, the temperature deviation is monitored by an infrared thermometer for each pass to obtain a high-entropy alloy.

[0091] The obtained high-entropy alloy was first wire-cut into 1mm thick sheets, and then tensile specimens with a total length of 40mm, a width of 5mm, and an arc of 0.5mm were wire-cut. Tensile cyclic testing at room temperature was performed using a mechanical testing machine, and the specimens exhibited approximately 1.5% hyperelastic strain at room temperature. The elastic moduli of the prepared high-entropy alloy at 100℃, 50℃, and -50℃ were 65GPa, 33GPa, and 51GPa, respectively, far exceeding the requirements for constant elasticity. Therefore, the prepared high-entropy alloy exhibits hyperelasticity over a wide temperature range, but the modulus changes drastically with temperature, and it does not possess a constant elastic effect.

[0092] Comparative Example 2

[0093] The high-entropy alloy was prepared in a manner similar to that of Example 1, except that no hot forging treatment was performed, i.e.:

[0094] Select metal raw materials with a purity of 99.99% or higher and the following atomic ratios: Ti 28.4%, Zr 28.4%, Hf 28.4%, Ta 8.8%, Nb 6%, with a metal mass of 1 kg, for later use;

[0095] Place the crucible used to hold the sample into a muffle furnace, evacuate to negative pressure, heat to 400°C for one hour, hold for three hours, and then remove it.

[0096] The crucible containing the above-mentioned raw materials was placed inside the large crucible of the vacuum induction furnace. The large dry pot was then placed in the coil of the vacuum induction furnace. A vacuum was then drawn, and the furnace was further purged with argon gas three times. Finally, the furnace was evacuated until the pressure was less than 1.3 × 10⁻⁶. - 3 Pa, at this time, argon gas is introduced as a protective gas to keep the furnace chamber pressure at 0.05Pa; at the beginning of melting, the heating power of the vacuum induction furnace is adjusted to 50W, and then the power is increased as the required temperature rises, up to a maximum of 100W; after all the components are melted together, the rocker is turned to pour the alloy liquid onto the cooling platform to obtain the melted alloy ingot, which is then naturally cooled to room temperature in an inert atmosphere such as argon gas, and the alloy ingot is taken out.

[0097] The surface of the alloy ingot can be polished, and this product is referred to as a high-entropy alloy.

[0098] The obtained high-entropy alloy was first wire-cut into thin sheets with a thickness of 1 mm, and then wire-cut into tensile specimens with a total length of 40 mm, a width of 5 mm, and an arc of 0.5 mm. Tensile cycle tests were conducted at room temperature using a mechanical testing machine. The results showed that the obtained high-entropy alloy did not have hyperelasticity, but only the linear elasticity of the material itself.

[0099] The obtained high-entropy alloy wire was cut into cuboids of 25×2.5×1mm and subjected to dynamic modulus testing on a dynamic thermomechanical analyzer. The results showed that the obtained high-entropy alloy did not have a stage with relatively small modulus change, that is, it did not have constant elasticity.

[0100] It should be specifically noted that the foregoing embodiments are merely illustrative examples of the technical solutions of this invention and do not constitute a limiting interpretation of the scope of protection of the claims. Those skilled in the art can make equivalent substitutions, reorganize technical elements, or modify the described technical features without departing from the scope defined by the claims, and the resulting improvements still fall within the protected scope of this invention's patent rights. It should be understood that any adaptive modifications based on the core inventive concept of this invention, as long as their technical features fall within the scope of the technical solutions set forth in the claims, are considered to be included within the legal protection scope of this invention.

[0101] The substantive scope of protection of this invention is strictly defined based on the claims and their equivalent technical features as finally authorized by the State Intellectual Property Office. The description of embodiments in the specification should not be used as a basis for limiting the interpretation of the claims.

Claims

1. A method for preparing a high-entropy alloy possessing both constant elasticity and hyperelasticity, characterized in that, Includes the following steps: Step 1: Ti, Zr, Hf, Ta and Nb are smelted to obtain Ti. a Zr b Hf c Ta d Nb e The alloy ingot, wherein a, b, c, d, and e are the atomic percentages of the five elements, where a = 25~30, b = 25~30, c = 25~30, d = 5~15, e = 4~8, and a+b+c+d+e = 100; Step 2: Hot forging the alloy ingot to obtain a high-entropy alloy.

2. The method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity properties according to claim 1, characterized in that, In step 1, the purity of Ti, Zr, Hf, Ta and Nb is not less than 99.99%.

3. The method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity as described in claim 1, characterized in that, In step 1, before melting, a vacuum is first drawn and the gas is purged with an inert gas, then the vacuum is drawn again until the gas pressure is less than 1.3 × 10⁻⁶. - 3 Pa, with inert gas as the protective gas, the gas pressure during smelting is 0.03~0.06 Pa.

4. The method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity as described in claim 1, characterized in that, In step 1, when the melting begins, the heating power of the vacuum induction furnace is adjusted to 50W.

5. The method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity as described in claim 1, characterized in that, In step 2, hot forging is performed at 1100°C.

6. The method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity as described in claim 1, characterized in that, In step 2, the thickness reduction rate is 50%.

7. The method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity as described in claim 1, characterized in that, The balance between constant elasticity and hyperelasticity of high-entropy alloys can be adjusted by regulating the Nb ratio and hot forging parameters.

8. A high-entropy alloy, characterized in that, It is prepared by a method for preparing a high-entropy alloy with both constant elasticity and hyperelasticity according to any one of claims 1-7.

9. The high-entropy alloy according to claim 8, characterized in that, The high-entropy alloy has constant elasticity at -150~200℃ and recoverable strain of 1.5~2.6%.

10. An application characterized in that, The high-entropy alloy as described in claim 8 or 9 is used in aerospace.

Images