A method for functional regulation of a nickel-titanium-tantalum-hafnium shape memory alloy wire

Abstract

The present invention relates to a method for functional regulation of a nickel-titanium-tantalum-hafnium shape memory alloy wire, and relates to the technical field of shape memory alloys. The present invention performs different heat treatments on the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wire to endow it with different functional characteristics: annealing the alloy wire at 450°C to 550°C to obtain a wide-temperature-range superelastic nickel-titanium-tantalum-hafnium alloy wire; or annealing the alloy wire at 600°C to 900°C to obtain a high-temperature shape memory nickel-titanium-tantalum-hafnium alloy wire. The method for functional regulation of the nickel-titanium-tantalum-hafnium shape memory alloy wire of the present invention can enable the nickel-titanium-tantalum-hafnium alloy to achieve wide-temperature-range superelasticity or high-temperature shape memory performance, and the nickel-titanium-tantalum-hafnium alloy also has strong X-ray visibility, and has the characteristics of simple regulation method, simple process and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of shape memory alloys, and particularly to a method for functional regulation of a Ni-Ti-Ta-Hf shape memory alloy wire. Background Art

[0002] At present, the superelastic strain of commercially available Ni-Ti shape memory alloys is about 8%, but the temperature range is only -20°C to 80°C, which cannot meet some application fields requiring wide-temperature-range superelasticity, such as the space field (-150°C to 120°C), the automotive field (-50°C to 150°C), etc.

[0003] To achieve wide-temperature-range superelasticity, methods such as strain glass and nano-domains including nanocrystallization have been introduced into Ni-Ti-based shape memory alloys. These methods have been proven to be able to expand the superelastic temperature range of Ni-Ti alloys. However, after these Ni-Ti-based alloys are heated to a certain temperature, the superelastic strain gradually decreases, and they do not have a high-temperature shape memory effect. For example, the literature "Ma Zhiyuan. Research on NiTi-based shape memory alloys with wide-temperature-range high superelastic stress. China University of Petroleum (Beijing), 2021" reported nanocrystalline Ni-Ti-Nb wire, whose superelastic temperature range reached -196°C to 160°C, and the superelastic strain in the low-temperature region exceeded 5%. However, the superelastic strain of this alloy wire was lower than 5% after the temperature exceeded 100°C. The invention patent with the patent number CN104032188 B discloses a Ti-Zr-Nb-Ta shape memory alloy with wide-temperature-range superelasticity and its preparation method, which has wide-temperature-range (-196°C to 135°C) superelasticity and high-temperature shape memory effect, but its maximum superelastic strain is only 5%, and the maximum shape memory strain is only 3.34%.

[0004] In minimally invasive interventional surgery, the X-ray visibility of the guide wire directly determines whether the doctor can accurately position and release the catheter or instrument to ensure its arrival at the lesion site. However, commercially available Ni-Ti alloy guide wires are restricted by low X-ray visibility, and new methods are urgently needed to overcome this disadvantage and promote the further application of Ni-Ti guide wires in micro medical interventional surgery.

[0005] In summary, to further expand the application of shape memory alloys in engineering fields such as space exploration and automobiles and biomedical fields, etc., it is urgent to develop a method for functional regulation of shape memory alloys to meet the application requirements in multiple fields. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for functional regulation of a Ni-Ti-Ta-Hf shape memory alloy wire to solve the problems existing in the above-mentioned prior art, realize adjustable wide-temperature-range high superelasticity and high-temperature shape memory effect of the shape memory alloy wire, and make the alloy material have strong X-ray visibility.

[0007] To achieve the above purpose, the present invention provides the following solutions:

[0008] The present invention performs different heat treatments on cold-drawn (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wires to endow them with different functional characteristics:

[0009] Wide-temperature-range superelasticity: The (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wires annealed at 450°C to 550°C have wide-temperature-range superelasticity. In the temperature range of 18°C to 200°C, 2.9% ≤ superelastic strain ≤ 7.6%, and 236 MPa ≤ superelastic stress ≤ 1600 MPa; among them, the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wires annealed at 450°C have a superelastic strain exceeding 5% at 37°C and can be used to make medical guide wires.

[0010] High-temperature shape memory effect: The (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wires annealed at 600°C to 900°C have a high-temperature shape memory effect. The strain start recovery temperature is between 90.8°C and 152.6°C, and the maximum shape memory strain is 6.1%. Moreover, the wires obtained by annealing treatment at 600°C to 900°C also have superelastic properties in the range of 120°C to 130°C, and the superelastic strain can reach 6%.

[0011] In the nickel-titanium-tantalum-hafnium shape memory alloy wires of the present invention, due to the addition of a high density of tantalum elements, the X-ray visibility of the alloy can be significantly enhanced.

[0012] The present invention can achieve that the shape memory alloy wires still have a superelastic strain exceeding 6% when the temperature is higher than 100°C, and can also achieve a high-temperature shape memory strain of 6.1%, thus meeting the requirements of high-temperature shape memory and superelastic functional components from room temperature to 150°C. This is mainly because the addition of Ta and Hf increases the martensitic transformation temperature of the alloy and the transformation strain induced by the martensitic transformation in the alloy; the addition of Ta can improve the processing performance of the alloy wires, which is beneficial to obtaining nano-structured alloy wires by combining cold drawing and annealing, thereby broadening the temperature range of the alloy's superelasticity.

[0013] Preferably, the functional regulation method of the nickel-titanium-tantalum-hafnium shape memory alloy wires of the present invention includes the following steps:

[0014] Prepare (Ni 49.59 Ti 45.41 Ta5) 97Hf3 alloy ingot, and then wire materials with a diameter of 2 - 3 mm are obtained through forging and hot drawing. The deformation amount of the hot drawing treatment is 30 - 40% per pass, and the deformation temperature is 750 °C - 850 °C; then the wire materials of (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy with a diameter of 2 - 3 mm are cold drawn to 0.2 - 1.5 mm. The cold drawing deformation amount is 10 - 20% per pass, and the intermediate annealing temperature between passes is 600 °C - 700 °C;

[0015] The wire materials of (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy obtained by cold drawing are annealed at 450 °C - 550 °C for 1 - 5 minutes, and then quenched in water to obtain wire materials with superelasticity in a wide temperature range; the more preferred annealing temperature is 450 °C;

[0016] The wire materials of (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy obtained by cold drawing are annealed at 600 °C - 900 °C for 1 - 5 minutes, and then quenched in water to obtain wire materials with high - temperature shape memory effect. The more preferred annealing temperature is 600 °C - 800 °C.

[0017] The method of the present invention can achieve that the maximum temperature of the superelastic strain of the nickel - titanium - tantalum - hafnium alloy wire materials can reach 200 °C. Compared with the 80 °C that the existing commercial nickel - titanium alloy wire materials can reach, the high - temperature region is significantly expanded, and it has stronger X - ray visibility, and can be used for making medical guide wires, high - temperature drive wires, etc.

[0018] The present invention discloses the following technical effects:

[0019] The method for regulating the functions of the nickel - titanium - tantalum - hafnium shape - memory alloy wire materials of the present invention can enable the nickel - titanium - tantalum - hafnium alloy to achieve superelasticity in a wide temperature range or high - temperature shape - memory performance, and the nickel - titanium - tantalum - hafnium alloy also has stronger X - ray visibility.

[0020] The regulation method provided by the present invention is simple, the process is simple, and the cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 For the annealing treatment at 500 °C in Embodiment 1 of the present invention (Ni49.59 Ti 45.41 Ta5) 97 Tensile loading and unloading stress-strain curves of the Hf3 alloy wire (test temperature 150 °C);

[0023] Figure 2 For the 500 °C annealing treatment in Example 1 of the present invention (Ni 49.59 Ti 45.41 Ta5) 97 Comparison photo of the Hf3 alloy wire and X-ray;

[0024] Figure 3 For the 550 °C annealing treatment in Example 2 of the present invention (Ni 49.59 Ti 45.41 Ta5) 97 Tensile loading and unloading stress-strain curves of the Hf3 alloy wire (test temperature 150 °C);

[0025] Figure 4 For the 550 °C annealing treatment in Example 2 of the present invention (Ni 49.59 Ti 45.41 Ta5) 97 Tensile loading and unloading stress-strain curves of the Hf3 alloy wire (test temperature 18 °C);

[0026] Figure 5 For the 450 °C annealing in Example 3 of the present invention (Ni 49.59 Ti 45.41 Ta5) 97 Tensile loading and unloading stress-strain curves of the Hf3 alloy wire (test temperature 37 °C);

[0027] Figure 6 For the 600 °C annealing in Example 4 of the present invention (Ni 49.59 Ti 45.41 Ta5) 97 Strain-temperature curve of the Hf3 alloy wire (constant stress 300 MPa);

[0028] Figure 7 For the 800 °C annealing in Example 5 of the present invention (Ni 49.59 Ti 45.41 Ta5) 97 Strain-temperature curve of the Hf3 alloy wire (constant stress 300 MPa). Detailed implementation manners

[0029] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0030] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0032] Without departing from the scope or spirit of the present invention, various improvements and variations can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are merely exemplary.

[0033] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0034] Example 1 Preparation of Ni-Ti-Ta-Hf alloy wire with wide temperature range and high superelasticity

[0035] (1) Prepare an ingot of (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy by vacuum induction melting method, and then obtain a wire with a diameter of 2 mm through forging and hot drawing with a deformation amount of 30% per pass and a deformation temperature of 750 °C;

[0036] (2) Cold draw the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wire with a diameter of 2 mm to 0.2 mm, with a cold drawing deformation amount of 10% per pass and an intermediate annealing temperature of 600 °C between passes;

[0037] (3) The (Ni 49.59 Ti 45.41 Ta5) 97The Hf3 alloy wire is annealed at 500 °C for 2 minutes, then quenched in water to obtain a wire with high elasticity in a wide temperature range.

[0038] Using a low-speed diamond cutting saw, cut a tensile specimen with a length of 45 mm from the above-prepared product (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 wire, and test its superelasticity at different temperatures in the temperature control box of an Instron-3365 universal material testing machine. First, adjust the test temperatures to 18 °C, 40 °C, 60 °C, 80 °C, 100 °C, 120 °C, 140 °C, 150 °C, etc. respectively. After the temperature is stable, load it to a certain deformation amount, and then unload it. Measure the recovery strain after unloading, which is the superelastic strain. The test results show that the superelastic temperature range of this alloy wire is from room temperature to 200 °C, 4.1% ≤ superelastic strain ≤ 7.6%, 289 MPa ≤ superelastic stress ≤ 1523 MPa.

[0039] The tensile stress-strain curve obtained at 150 °C is as Figure 1 shown. When the total strain is 7%, the superelastic strain of the sample reaches 5.6%.

[0040] Table 1 summarizes the superelastic strain and stress of Example 1 at different temperatures, with a total strain of 8%.

[0041]

[0042] Figure 2 The X-ray comparison photo of the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wire with a diameter of 1.5 mm and the NiTi alloy wire is shown. It can be seen that the X-ray visibility of the former is better than that of the latter.

[0043] Example 2 Preparation of a nickel-titanium-tantalum-hafnium alloy wire with high elasticity in a wide temperature range

[0044] (1) Prepare a (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy ingot by vacuum induction melting method, and then obtain a wire with a diameter of 1.5 mm through forging and hot drawing with a deformation amount of 30% per pass and a deformation temperature of 850 °C;

[0045] (2) Cold-draw the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wire with a diameter of 1.5 mm to 0.2 mm, with a cold-drawing deformation amount of 10% per pass and an intermediate annealing temperature of 650 °C during passes;

[0046] (3) Anneal the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wire at 550 °C for 2 minutes, then quench in water to obtain a wire with high-temperature superelasticity in a wide temperature range.

[0047] Using a low-speed diamond cutting saw, cut a tensile specimen with a length of 45 mm from the above-prepared product (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 wire, and test its superelasticity at different temperatures in the temperature control box of an Instron-3365 universal material testing machine. First, adjust the test temperatures to 18 °C, 40 °C, 60 °C, 80 °C, 100 °C, 120 °C, 140 °C, 150 °C, etc. respectively. After the temperature is stable, load it to a certain deformation amount, then unload it, and measure the recovery strain after unloading, which is the superelastic strain.

[0048] The results show that the superelastic temperature range of this alloy wire is 18 °C to 200 °C, 2.9% ≤ superelastic strain ≤ 7.3%, 287 MPa ≤ superelastic stress ≤ 1496 MPa. The tensile stress-strain curve obtained at 150 °C is as Figure 3 shown. When the total strain is 6.5%, the superelastic strain of the sample reaches 6.3%. The tensile stress-strain curve obtained at 18 °C is as Figure 4 shown. When the total strain is 3.75%, the superelastic strain of the sample reaches 2.9%. Table 2 summarizes the superelastic strain and stress tested at different temperatures in Example 2, and the total strain is 8%.

[0049] Table 2

[0050]

[0051] Example 3 Preparation of a nickel-titanium-tantalum-hafnium alloy wire with a superelastic strain exceeding 5% at 37 °C

[0052] (1) Prepare a (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy ingot by vacuum induction melting method, and then obtain a wire with a diameter of 2 mm through forging and hot drawing with a deformation amount of 30% per pass and a deformation temperature of 800 °C;

[0053] (2) Cold-draw the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wire with a diameter of 2 mm to 0.2 mm, with a cold-drawing deformation amount of 10 - 20% per pass and an intermediate annealing temperature of 600 - 700 °C;

[0054] (3) Anneal the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wire at 450 °C for 2 minutes, then quench in water to obtain a nickel-titanium-tantalum-hafnium alloy wire, and the superelastic strain of this wire exceeds 5% at 37 °C.

[0055] Using a low-speed diamond cutting saw, cut a tensile specimen with a length of 45 mm from the above-prepared (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 shape memory alloy wire, and test its superelasticity at 37 °C in the temperature control box of an Instron-3365 universal material testing machine. First, adjust the test temperature to 37 °C. After the temperature is stable, load it to a pre-deformation of 5.8%, then unload it, and measure the recovery strain after unloading, which is the superelastic strain. The tensile stress-strain curve obtained at 37 °C is as Figure 5 shown, and the superelastic strain of the sample reaches 5.3%.

[0056] The results show that the superelastic temperature range of this alloy wire is from room temperature to 200 °C, 4.8% ≤ superelastic strain ≤ 7%, and 239 MPa ≤ superelastic stress ≤ 1564 MPa. Table 3 summarizes the superelastic strain and stress tested at different temperatures in Example 3, and the total strain is 8%.

[0057] Table 3

[0058]

[0059] Example 4 Preparation of Nickel-Titanium-Tantalum-Hafnium Wire with High-Temperature Shape Memory Effect

[0060] (1) Prepare a (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy ingot by vacuum induction melting method, and then obtain a wire with a diameter of 2 mm through forging and hot drawing with a deformation of 30% per pass and a deformation temperature of 750 °C;

[0061] (2) Cold draw the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wire with a diameter of 2 mm to 0.2 mm, with a cold drawing deformation of 10% per pass and an intermediate annealing temperature of 650 °C during passes;

[0062] (3) The (Ni 49.59 Ti 45.41 Ta5) 97The Hf3 alloy wire is annealed at 600 °C for 2 minutes, then quenched in water to obtain a wire with high-temperature shape memory effect.

[0063] Using a low-speed diamond cutting saw, a 20-mm-long specimen is cut from the above-prepared (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 wire. The shape memory effect under different constant stresses is tested on a TA Q850 dynamic mechanical analyzer (DMA) in tensile mode. First, the sample is clamped, then the test temperature is raised to 250 °C to ensure that the sample is fully transformed into austenite. After the temperature stabilizes, a load of 300 MPa is applied, and a constant stress of 300 MPa is maintained during the subsequent cooling (down to 0 °C) and heating (up to 250 °C) processes. The relationship between strain and temperature is measured. The superelasticity at different temperatures is tested in the temperature control box of an Instron-3365 universal material testing machine. The results show that it also has superelastic properties at 120 - 130 °C, and the superelastic strain at 120 °C can reach 6%.

[0064] The strain-temperature curve obtained under a constant stress of 300 MPa is as Figure 6 shown. In the figure, ε R is the shape memory strain of the sample, reaching 6.1%. At the same time, the alloy begins to recover strain at 125 °C during heating. Table 4 summarizes the shape memory strains under different applied stresses in Example 4.

[0065] Table 4

[0066]

[0067] Example 5 Preparation of nickel-titanium-tantalum-hafnium wire with high-temperature shape memory effect

[0068] (1) Prepare an (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy ingot by vacuum induction melting, and then obtain a wire with a diameter of 2 mm through forging and hot drawing with a deformation amount of 30% per pass and a deformation temperature of 750 °C;

[0069] (2) Cold-draw the (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 alloy wire with a diameter of 2 mm to 0.2 mm, with a cold-drawing deformation amount of 10% per pass and an intermediate annealing temperature of 650 °C during passes;

[0070] (3) The (Ni 49.59 Ti 45.41 Ta5) 97The Hf3 alloy wire is annealed at 800 °C for 2 minutes, then quenched in water to obtain a wire with high-temperature shape memory effect.

[0071] Using a low-speed diamond cutting saw, a 20-mm-long specimen is cut from the above-prepared (Ni 49.59 Ti 45.41 Ta5) 97 Hf3 wire, and its shape memory effect under different constant stresses is tested in a tensile mode on a TA Q850 dynamic mechanical analyzer (DMA). First, the sample is clamped, then the test temperature is raised to 250 °C to ensure that the sample is completely transformed into austenite. After the temperature stabilizes, it is loaded to 300 MPa, and a constant stress of 300 MPa is maintained during the subsequent cooling (cooling to 0 °C) and heating (heating to 250 °C) processes, and the relationship between strain and temperature is measured. Its superelasticity at different temperatures is tested in the temperature control box of an Instron-3365 universal material testing machine. The results show that it also has superelastic properties at 120 - 130 °C, and the superelastic strain at 120 °C can reach 6%.

[0072] The strain-temperature curve obtained under a constant stress of 300 MPa is as Figure 7 shown. In the figure, ε R is the shape memory strain of the sample, reaching 4.5%, and the alloy starts to undergo strain recovery at 152 °C during heating. Table 5 summarizes the shape memory strains under different applied stresses.

[0073] Table 5

[0074]

[0075] The nickel-titanium-tantalum-hafnium shape memory alloy wire prepared by the present invention has high superelasticity in a wide temperature range, good high-temperature shape memory effect, and stronger X-ray visibility than nickel-titanium alloys. The preparation method of the present invention can adjust the service temperature of the nickel-titanium-tantalum-hafnium alloy wire, as well as its superelasticity and shape memory effect, by adjusting the coordination relationship between the deformation amount and the heat treatment temperature, and can meet the requirements of shape memory and superelastic functional components from room temperature to 150 °C. The preparation method is simple and has low cost.

[0076] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for functional regulation of a nickel-titanium-tantalum-hafnium alloy wire, characterized in that, The composition of the nickel-titanium-tantalum-hafnium alloy wire is (Ni 49.59 Ti 45.41 Ta5) 97 Hf3; The functional regulation method includes the following steps: Anneal the nickel-titanium-tantalum-hafnium alloy wire at 450°C to 550°C to obtain a wide-temperature-range superelastic nickel-titanium-tantalum-hafnium alloy wire; Or Anneal the nickel-titanium-tantalum-hafnium alloy wire at 600°C to 900°C to obtain a high-temperature shape memory nickel-titanium-tantalum-hafnium alloy wire; The annealing time for both the 450°C to 550°C annealing and the 600°C to 900°C annealing is 1 - 5 minutes; The nickel-titanium-tantalum-hafnium alloy wire is obtained by successively performing hot drawing treatment and cold drawing treatment on a nickel-titanium-tantalum-hafnium alloy ingot; The deformation amount of the hot drawing treatment is 30 - 40% per pass, and the deformation temperature is 750 - 850°C; The deformation amount of the cold drawing treatment is 10 - 20% per pass, and the intermediate annealing temperature between passes is 600 - 700°C.

2. A nickel-titanium-tantalum-hafnium alloy wire prepared by the functional regulation method according to claim 1.

3. The application of the nickel-titanium-tantalum-hafnium alloy wire according to claim 2 in the fields of space, automobiles, robots, and medical devices.

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