Wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy and preparation method thereof

Abstract

The invention provides a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy and a preparation method, and the wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy comprises the following chemical components in percentage by mass: 30%-50% of nickel, 35%-48% of titanium, 5%-16% of copper and 2.5%-10% of vanadium. According to the shape memory alloy, by adjusting the element composition of the shape memory alloy and optimizing the preparation scheme, the alloy shows the hyperelastic mechanical behavior and the shape memory effect within the temperature range of-65 DEG C to 200 DEG C, the recoverable strain is at least 3%, and the adiabatic temperature drop reaches 4.3 DEG C to 11.2 DEG C during unloading.

Description

Technical Field

[0001] This application relates to the fields of elastocaloric cooling / heating and aerospace applications, and particularly to a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy and a preparation method thereof. Background Art

[0002] Currently, vapor compression refrigeration systems are commonly used in the field of refrigeration technology. This system relies on refrigerants such as freon and hydrocarbons, and has defects such as flammability, explosiveness, and high greenhouse effect. For example, difluoromethane (R32), as a freon refrigerant, has a global warming potential (GWP) that is 650 times that of carbon dioxide, seriously threatening environmental safety. To address the above defects of vapor compression refrigeration systems, elastocaloric refrigeration technology based on solid-state phase change materials has become a research hotspot. This technology realizes endothermic and exothermic processes by mechanically driving a shape memory alloy to undergo austenite-martensite two-way reversible phase change, and has advantages such as zero greenhouse gas emissions, high energy efficiency ratio, and two-way temperature control.

[0003] However, the nickel-titanium shape memory alloy, the core material of existing elastocaloric refrigeration technology, has significant limitations: Firstly, its superelastic temperature range is narrow, and it only exhibits a stable elastocaloric effect near room temperature. When the environmental temperature exceeds 100°C or is lower than 0°C, the phase change characteristics deteriorate rapidly; Secondly, the fatigue life and cyclic stability of the material are limited in a wide temperature range. This makes it difficult for it to work stably in extreme temperature scenarios such as spacecraft temperature control devices and deep space exploration equipment (for example, the temperature on the lunar surface varies between -180°C and 150°C), severely restricting the application scope of elastocaloric refrigeration technology. Summary of the Invention

[0004] To solve the above problems, this application provides a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy and a preparation method thereof. This shape memory alloy can exhibit excellent superelasticity in a relatively wide temperature range.

[0005] Specifically, this application provides: According to an embodiment of the first aspect of this application, a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy is provided. By mass percentage, the chemical composition of this shape memory alloy is: nickel: 30% - 50%, titanium: 35% - 48%, copper 5% - 16%, and vanadium 2.5% - 10%.

[0006] According to an embodiment of the second aspect of this application, a preparation method of a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy is provided, including: Melting raw materials containing titanium, nickel, copper, and vanadium to obtain an ingot; by mass percentage, the chemical composition of the above raw materials is: nickel: 30% - 50%, titanium: 35% - 48%, copper 5% - 16%, and vanadium 2.5% - 10%; Cut the ingot into circular slices, and perform cold rolling or high-pressure torsion to obtain a shape memory alloy thin sheet; Anneal and quench the shape memory alloy thin sheet to obtain a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy.

[0007] Exemplarily, melting the raw materials containing titanium, nickel, copper, and vanadium to obtain an ingot, including: Use arc melting or induction melting or levitation induction melting for the raw materials of titanium, nickel, copper, and vanadium to obtain an ingot.

[0008] Specifically, arc melting includes: After evacuating the arc melting furnace, pass a protective gas, and the above-mentioned protective gas includes at least one of high-purity argon, a mixture of hydrogen and argon, and nitrogen; Induction melting or levitation induction melting includes: After evacuating the induction melting furnace or levitation induction melting furnace, pass a protective gas, and the above-mentioned protective gas includes at least one of high-purity argon, a mixture of hydrogen and argon, and nitrogen.

[0009] Exemplarily, the current of arc melting is 100 A to 1000 A, and the ingot morphology formed by arc melting includes: Button-shaped, with a diameter of 5 mm to 1000 mm and a thickness of 1 mm to 600 mm; and / or, Cylindrical rod-shaped formed by suction casting, with a diameter of 1 mm to 50 mm and a height of 1 mm to 800 mm.

[0010] Exemplarily, the current of induction melting or levitation induction melting is 100 A to 300 A, the oscillation frequency is 1 kHz to 80 kHz, and the ingot formed by the induction melting is cylindrical rod-shaped, with a diameter of 1 mm to 1000 mm and a height of 3 mm to 1000 mm.

[0011] Exemplarily, annealing and quenching the shape memory alloy thin sheet includes: Anneal the shape memory alloy thin sheet using an annealing process with an annealing temperature of 200 °C to 800 °C and an annealing time of 0.01 hour to 12 hours; Immediately put the annealed shape memory alloy thin sheet into water, oil, or an ice-water mixture for quenching.

[0012] Exemplarily, the shape memory alloy exhibits superelastic mechanical behavior in the temperature range of -65 °C to 200 °C, generates at least 3% strain under a compressive stress of 100 MPa to 2000 MPa, and after the load is removed, the shape memory alloy can recover its original shape and size.

[0013] Exemplarily, the impurities of the shape memory alloy meet the following requirements: carbon ≤ 0.1% by mass, oxygen plus nitrogen ≤ 1% by mass, iron ≤ 0.1% by mass, hydrogen ≤ 0.1% by mass, and other impurities ≤ 0.5% by mass.

[0014] According to an embodiment of the third aspect of the present application, a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy product is provided. At least a part of the shape memory alloy product is made of the shape memory alloy as described in the first aspect. The shape memory alloy product is applied to aerospace components, biomedical materials, solid-state elastocaloric refrigeration components, solid-state elastocaloric heating components, mechanical engineering components, automotive components, and / or building components.

[0015] The technical effects of the present application are as follows: The present application provides a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy and a preparation method thereof. The nickel-titanium-copper-vanadium alloy of the present application is a functional material with reversible martensitic transformation. Its martensitic transformation and its reverse transformation can be induced by temperature or stress, and correspondingly, it can exhibit superelasticity and the elastocaloric effect. Compared with the existing nickel-titanium shape memory alloy, the present application adjusts the element composition and optimizes the preparation scheme, so that the nickel-titanium-copper-vanadium shape memory alloy shows superelastic mechanical behavior and shape memory effect in the temperature range of -65°C to 200°C, the recoverable strain is at least 3%, and the adiabatic temperature drop during unloading reaches 4.3°C to 11.2°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following is a brief description of the drawings, which are for showing the exemplary embodiments disclosed in the present application and are not intended to limit them.

[0017] Figure 1 is a flowchart of a method for preparing a shape memory alloy provided by an embodiment of the present application; Figure 2 is a processing schematic diagram of preparing a shape memory alloy thin plate by high-pressure torsion provided by an embodiment of the present application; Figure 3 is a processing schematic diagram of preparing a shape memory alloy thin plate by cold rolling provided by an embodiment of the present application; Figure 4 is a stress-strain relationship diagram of the shape memory alloy prepared in Example 1 of the present application during the compression loading and unloading process in the environmental temperature range of -65°C to 200°C.

[0018] Figure 5 is an adiabatic temperature drop performance diagram of the shape memory alloy prepared in Example 1 of the present application during compression unloading in the environmental temperature range of -65°C to 200°C. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The components, methods, and devices disclosed in this application can be more fully understood with reference to the accompanying drawings. For the convenience and ease of illustration of this application, these drawings are only schematic representations and are not intended to represent the relative sizes and dimensions of the device or its components, and / or to define or limit the scope of the exemplary embodiments.

[0020] Although specific terms are used in the following description for clarity, these terms are intended to refer only to the specific structures of the embodiments illustrated in the drawings and are not intended to define or limit the scope of this application. In the drawings and the following description, it should be understood that like numerical reference labels refer to components with similar functions.

[0021] Unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" include plural referents.

[0022] The numerical values in the specification and claims of this application should be understood to include the same values when reduced to the same number of significant digits, and values that differ from the stated value by less than the experimental error of the conventional measurement techniques used to determine that value in the type described in this application.

[0023] All ranges disclosed in this application include the listed end values and are combinable independently (e.g., the range "200 °C to 800 °C" includes the end values 200 °C and 800 °C and includes all intermediate values).

[0024] Values modified by one or more terms such as "about" and "substantially" are not limited to the specified exact values. The terms used to indicate approximation can conform to the precision of the instrument used to measure the value. The modifier "about" should also be considered to disclose the range determined by the absolute values of the two end values. For example, the expression "about 2 to about 4" also discloses the range "2 to 4".

[0025] This application relates to temperature ranges. It is noted that these temperatures refer to the atmosphere temperature to which the alloy is exposed or the set temperature of the furnace; the alloy itself does not need to reach these temperatures.

[0026] As used in this application, the term "superelasticity" refers to the phenomenon that a shape memory alloy generates a strain much larger than the strain at the elastic limit of a general metal structural material under an external force, usually more than 1%, and the strain can spontaneously recover during unloading. That is, in the austenite phase state, due to the action of an external stress, stress-induced martensitic transformation occurs, so that the alloy exhibits mechanical behavior different from ordinary materials. Its elastic limit is much larger than that of ordinary materials and no longer follows Hooke's law. Compared with the shape memory property, superelasticity is driven by force. Generally speaking, superelasticity can be divided into two categories: linear superelasticity and non-linear superelasticity. In the former, the stress and strain in the stress-strain curve are close to a linear relationship. Non-linear superelasticity refers to the result of stress-induced martensitic transformation and its reverse transformation occurring respectively during loading and unloading within a certain temperature range above the austenite phase transformation end temperature (A f )).

[0027] The term "recoverable strain" refers to the magnitude of the strain that a material or structure can recover after being loaded and unloaded under force, reflecting the elastic or superelastic mechanical properties of the material or structure.

[0028] The term "temperature range" refers to the difference between the highest and lowest ambient temperatures at which a material can be used. The term "wide temperature range" means that the material can maintain the required performance in a relatively wide ambient temperature range. Usually, a temperature range above 100 °C can be regarded as a wide temperature range.

[0029] Specifically, the embodiment of this application provides a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy. By mass percentage, the chemical composition of this wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy is: nickel: 30% - 50%, titanium: 35% - 48%, copper 5% - 16%, vanadium 2.5% - 10%. Compared with conventional nickel-titanium alloys, copper and vanadium are added to the wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy provided in this application and the element ratio is optimized, so that the alloy exhibits superelastic mechanical behavior and shape memory effect in the wide temperature range of -65 °C to 200 °C.

[0030] Correspondingly, this application also provides a preparation method for a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy. Figure 1 It is a flowchart of a preparation method for a shape memory alloy provided by an embodiment of this application. As Figure 1 shown, this method includes the following steps: S101, melting the raw materials of titanium, nickel, copper and vanadium to obtain an ingot.

[0031] In some embodiments, the smelting in this step can be arc smelting, induction smelting or levitation induction smelting. Among them, arc smelting refers to melting metal raw materials by generating high temperature (>3000 °C) through a high-voltage arc between electrodes, usually carried out under vacuum or inert gas protection, and the oxidation loss of active metals (such as titanium) can be precisely controlled; induction smelting or levitation induction smelting uses a medium- to high-frequency alternating magnetic field to induce eddy current heating in the metal to melt the material, with the characteristics of rapid and uniform heating, and is suitable for the large-scale preparation of high-conductivity alloys. Specifically, during the smelting process, after evacuating the arc smelting furnace, induction smelting furnace or levitation induction smelting furnace, through a protective gas, the protective gas here can include at least one of high-purity argon, a mixture of hydrogen and argon, and nitrogen. By evacuating and selecting a specific protective gas, the interference of other gases during the smelting process is effectively isolated, and metal oxidation and impurity generation are inhibited.

[0032] Exemplarily, during the arc smelting process, the current can be 100 A to 1000 A, and the ingot forms formed by arc smelting include: button-shaped, with a diameter of 5 mm to 1000 mm and a thickness of 1 mm to 600 mm; and / or, a cylindrical rod-shaped formed by suction casting, with a diameter of 1 mm to 50 mm and a height of 1 mm to 800 mm.

[0033] Exemplarily, during the induction smelting process or levitation induction smelting, the current can be 100 A to 300 A, the oscillation frequency is 1 kHz to 80 kHz, and the ingot formed by induction smelting is a cylindrical rod-shaped, with a diameter of 1 mm to 1000 mm and a height of 3 mm to 1000 mm.

[0034] S102, cut the above ingot into round slices, and perform high-pressure torsion or cold rolling to obtain a shape memory alloy thin plate.

[0035] The shape memory alloy thin plate refers to a sheet material prepared by plastic processing technologies such as high-pressure torsion or cold rolling, and is an intermediate form of the shape memory alloy in this application.

[0036] Figure 2 FIG. is a processing schematic diagram of preparing a shape memory alloy thin plate by high-pressure torsion provided by an embodiment of the present application, where 21, 22 and 23 are respectively an upper pressure head, a disc-shaped sample and a lower pressure head.

[0037] Figure 3 FIG. is a processing schematic diagram of preparing a shape memory alloy thin plate by cold rolling provided by an embodiment of the present application, where 31, 32 and 33 are respectively an upper pressure head, a long plate-shaped sample and a lower pressure head.

[0038] In addition to the illustrated high-pressure torsion and cold rolling, other plastic deformation processes can also be used to regulate the microstructure to achieve similar performance optimization goals.

[0039] S103, anneal and quench the above-mentioned shape memory alloy thin sheet to obtain a wide-temperature-range nickel-titanium-copper-vanadium shape memory alloy.

[0040] Exemplarily, an annealing process with an annealing temperature of 200 °C to 800 °C and an annealing time of 0.01 hour to 12 hours can be used to anneal the shape memory alloy thin sheet, and after annealing, the shape memory alloy thin sheet is immediately placed in water, oil or an ice-water mixture for quenching.

[0041] So far, the description of the Figure 1 shown process is completed.

[0042] Based on the preparation method given in the embodiments of the present application, the prepared shape memory alloy may contain impurities. When the impurities meet the following conditions, it does not affect the achievement of the technical effects pointed out in the present application: the impurities include carbon ≤ 0.1% by mass, oxygen plus nitrogen ≤ 1% by mass, iron ≤ 0.1% by mass, hydrogen ≤ 0.1% by mass, and other impurities ≤ 0.5% by mass. Here, the other impurities may include elements outside the components and inevitable impurities.

[0043] Based on the preparation method given in the embodiments of the present application, the prepared shape memory alloy exhibits superelastic mechanical behavior in the temperature range of -65 °C to 200 °C, generates at least 3% strain under a compressive stress of 100 MPa to 2000 MPa, and after the load is removed, the shape memory alloy can recover its initial shape and size.

[0044] Correspondingly, the embodiments of the present application also provide a shape memory alloy product, which is at least partially made of the shape memory alloy described in the above embodiments, and the shape memory alloy product can be applied to at least aerospace components, biomedical materials, solid-state elastic card refrigeration components, solid-state elastic card heating components, mechanical engineering components, automotive components and / or building components.

[0045] The following examples are provided to illustrate the alloys and preparation methods of the present application. These examples are illustrative only and are not intended to limit the disclosure to the materials, conditions or process parameters described therein.

[0046] Example 1 Mix titanium, nickel, copper and vanadium with a purity of at least 99.9 atomic% according to the mass percentages: nickel (Ni): 47%; titanium (Ti): 40%; copper (Cu): 8%; vanadium (V): 5% and add them to an arc melting furnace, evacuate to Pa, and then introduce high-purity argon with a purity of ≥99%. Adjust the current of the melting furnace to 150 A - 700 A. After melting the raw materials into an alloy, flip the sample and remelt it. A total of 5 melts are performed, with each melt lasting from 0.1 minute to 5 minutes, to obtain an alloy sample. Use wire cutting to cut the alloy sample into a circular shape. According to Figure 2 As shown, use a high-pressure torsion device. Apply a compressive stress of 2000 MPa, and then rotate the upper pressure head. Utilize the frictional force between the pressure head and the sample to perform torsional deformation on the sample. The upper pressure head rotates 10 circles relative to the lower pressure head, that is, 3600 degrees. Heat-treat the alloy material after high-pressure torsion at a temperature of 450 °C for 30 minutes. Immediately after heat treatment, quickly place it in water at room temperature for quenching, and the quenching time is 1 minute. Thus, the Ni-Ti-Cu-V shape memory alloy of Example 1 is obtained. Figure 4 Figure Figure 4 is a stress-strain relationship diagram of the shape memory alloy prepared in Example 1 of this application during the compression loading and unloading processes within the temperature range of -65 °C to 200 °C. As Figure 4 shown, this shape memory alloy exhibits superelastic mechanical behavior and shape memory effect within the ambient temperature range of -65 °C to 200 °C, and produces at least 3% recoverable strain under a compressive stress of 100 MPa to 2000 MPa. The adiabatic temperature drop during unloading of this shape memory alloy reaches 4.3 °C to 11.2 °C, as Figure 5 shown.

[0047] Example 2 Manufacture the Ni-Ti-Cu-V alloy of Example 2 basically according to the same composition and processing method as in Example 1, with the difference that the heat treatment temperature is 500 °C and the time is 30 minutes.

[0048] Example 3 Manufacture the Ni-Ti-Cu-V alloy of Example 3 basically according to the same composition and processing method as in Example 1, with the difference that the heat treatment temperature is 600 °C and the time is 60 minutes.

[0049] Example 4 Manufacture the Ni-Ti-Cu-V alloy of Example 4 basically according to the same processing method as in Example 2, with the difference that the composition is Ni49.5Ti42Cu6V2.5 (mass percentage).

[0050] Example 5 Manufacture the Ni-Ti-Cu-V alloy of Example 5 basically according to the same composition and heat treatment method as in Example 4, with the difference that room temperature (25 °C) cold rolling is adopted and the thickness reduction is 50%.

[0051] Example 6 The Ni-Ti-Cu-V alloy of Example 6 was manufactured by substantially the same processing method as in Example 5, except that the composition was Ni47Ti40Cu5V8 (mass percentage), and the cold rolling thickness reduction was 30%.

[0052] Example 7 The Ni-Ti-Cu-V alloy of Example 7 was manufactured by substantially the same processing method as in Example 6, except that the composition was Ni47.4Ti38Cu9V5.6 (mass percentage), and the rolling temperature was 30 °C.

[0053] Example 8 The Ni-Ti-Cu-V alloy of Example 8 was manufactured by substantially the same processing method as in Example 7, except that the composition was Ni35Ti40Cu15V10 (mass percentage), and hot rolling was used. The hot rolling temperature was 500 °C, that is, the material or structure was first placed in a 500 °C heating furnace for temperature rise treatment, and then the material was rapidly rolled. The rolled material or structure was heat-treated at 600 °C for 60 minutes.

[0054] Example 9 The Ni-Ti-Cu-V alloy of Example 9 was manufactured by substantially the same processing method as in Example 8, except that the composition was Ni30Ti48Cu16V6 (mass percentage).

[0055] Example 10 The Ni-Ti-Cu-V alloy of Example 10 was manufactured by substantially the same processing method as in Example 8, except that the composition was Ni50Ti35Cu9V6 (mass percentage).

[0056] The relevant data of the above Examples 1-10 are shown in Table 1. It can be seen from Table 1 that according to the preparation method provided in this application, the wide-temperature-range Ni-Ti-Cu-V shape memory alloys prepared in Examples 1-7 can all exhibit superelastic mechanical behavior in the temperature range of -65 °C to 200 °C, and the recoverable strain is at least 3%. For Examples 8-10, the materials were rolled by hot rolling, and the recoverable strain was less than 3% and was between 1% and 2%.

[0057] Table 1

[0058] It should be understood that the above disclosed variations and other features and functions or their alternatives can be combined into many other different systems or applications. Those skilled in the art can subsequently make various alternative ways, modifications, variations or improvements that are not currently foreseen or anticipated, and this is also intended to be covered by the appended claims.

Claims

1. A wide temperature range nickel-titanium-copper-vanadium shape memory alloy, characterized in that: The chemical composition of the wide temperature range nickel-titanium-copper-vanadium shape memory alloy is, by mass percentage, 30% to 50% nickel, 35% to 48% titanium, 5% to 16% copper and 2.5% to 10% vanadium.

2. A method for preparing a wide temperature range nickel-titanium-copper-vanadium shape memory alloy, characterized in that: include: Smelting raw materials containing titanium, nickel, copper and vanadium to obtain ingots; the chemical composition of the raw materials is as follows: nickel: 30% to 50%, titanium: 35% to 48%, copper: 5% to 16% and vanadium: 2.5% to 10% by mass percentage; Cutting the ingot into discs, and performing cold rolling or high-pressure twisting to obtain a shape memory alloy thin plate; The shape memory alloy thin plate is annealed and quenched to obtain a wide temperature range nickel-titanium-copper-vanadium shape memory alloy.

3. The preparation method according to claim 2, characterized in that: The process of smelting raw materials containing titanium, nickel, copper and vanadium to obtain an ingot comprises: The raw materials of titanium, nickel, copper and vanadium are melted by arc melting, induction melting or suspension induction melting to obtain ingots.

4. The preparation method according to claim 3, characterized in that: The arc melting comprises: After the arc melting furnace is evacuated, a protective gas is passed through, wherein the protective gas includes at least one of high-purity argon, a mixture of hydrogen and argon, and nitrogen; The induction melting or suspension induction melting comprises: After the induction melting furnace or the suspension induction melting furnace is evacuated, a protective gas is passed through, wherein the protective gas includes at least one of high-purity argon, a mixture of hydrogen and argon, and nitrogen.

5. The preparation method according to claim 3, characterized in that: The current of the arc melting is 100A to 1000A, and the ingot morphology formed by the arc melting includes: Button-shaped, with a diameter of 5 mm to 1000 mm and a thickness of 1 mm to 600 mm; and / or, The cylindrical rod is formed by suction casting, with a diameter of 1mm to 50mm and a height of 1mm to 800mm.

6. The preparation method according to claim 3, characterized in that: The current of the induction melting is 100A to 300A, the oscillation frequency is 1kHz to 80kHz, and the ingot formed by the induction melting is in the shape of a cylindrical rod with a diameter of 1mm to 1000mm and a height of 3mm to 1000mm.

7. The preparation method according to claim 2, characterized in that: The annealing and quenching of the shape memory alloy thin plate comprises: Annealing the shape memory alloy thin plate by adopting an annealing process with an annealing temperature of 200° C. to 800° C. and an annealing time of 0.01 hour to 12 hours; The annealed shape memory alloy thin plate is immediately placed in water, oil or ice-water mixture for quenching.

8. The preparation method according to claim 2, characterized in that: The wide temperature range nickel-titanium-copper-vanadium shape memory alloy exhibits superelastic mechanical behavior within a temperature range of -65°C to 200°C, produces at least 3% strain under a compressive stress of 100 MPa to 2000 MPa, and after the load is removed, the wide temperature range nickel-titanium-copper-vanadium shape memory alloy can recover its original shape and size.

9. The preparation method according to claim 2, characterized in that: The impurities of the shape memory alloy meet the following requirements: carbon ≤0.1% by mass, oxygen plus nitrogen ≤1% by mass, iron ≤0.1% by mass, hydrogen ≤0.1% by mass, and other impurities ≤0.5% by mass.

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