Nickel-titanium alloy wire, shaping method and application of nickel-titanium alloy wire

Abstract

The invention provides a nickel-titanium alloy wire, a shaping method and application of the nickel-titanium alloy wire. The shaping method comprises the following steps that S1, drawing is conducted before shaping, and the microstructure of nickel-titanium alloy obtained after drawing is formed by compounding amorphous and nanocrystalline; s2, the surface of the nickel-titanium alloy wire is sequentially sleeved with a heat insulation sleeve and a plastic film sleeve; and S3, the nickel-titanium alloy wire is powered on through direct current, shaping is conducted, cooling is conducted to the room temperature after power failure, and the surface temperature of the plastic film sleeve is smaller than or equal to 55 DEG C in the shaping process.

Description

Technical Field

[0001] The invention relates to the field of shape memory alloy processing, and in particular to a nickel-titanium alloy wire, a shaping method and applications thereof. Background Art

[0002] Nickel-titanium alloy is widely used in biomedical and other fields due to its excellent superelasticity, such as orthodontic wires, wearable medical devices, etc. In order to match the shape required by the application, the last process of nickel-titanium alloy is shaping treatment.

[0003] The existing shaping method is to fix the nickel-titanium alloy wire on a mold and then put it into a heating furnace for shaping. This method often requires a higher shaping temperature (usually 400°C-550°C) and a longer shaping time (usually greater than 5 minutes), which can easily lead to coarse grains, poor superelasticity, and is not convenient and energy-saving. The existing mold shaping method also has forming errors.

[0004] Therefore, a new low-temperature shaping method is needed that can ensure the microstructure of the nanocrystals after shaping, which is conducive to the material retaining good superelasticity, and can be directly shaped on the human body, which is more in line with customized needs. Summary of the invention

[0005] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a nickel-titanium alloy wire, a shaping method and applications thereof.

[0006] The present invention provides a nickel-titanium alloy wire shaping method having the following characteristics, comprising the following steps:

[0007] S1, drawing is performed before shaping, and the microstructure of the nickel-titanium alloy after drawing is a composite of amorphous and nanocrystalline;

[0008] S2, sequentially putting a heat-insulating sleeve and a plastic film sleeve on the surface of the nickel-titanium alloy wire;

[0009] S3, using direct current to energize the nickel-titanium alloy wire for shaping, and cooling it to room temperature after power off. During the shaping process, the surface temperature of the plastic film sleeve is ≤55°C.

[0010] The nickel-titanium alloy wire shaping method provided by the present invention may also have the following characteristics: wherein the amorphous content in step S1 is ≥ 20%.

[0011] The nickel-titanium alloy wire shaping method provided by the present invention may also have the following characteristics: wherein the thermal insulation sleeve material in step S2 comprises silicon dioxide nano-aerogel, porous vacuum silicon and glass fiber.

[0012] The nickel-titanium alloy wire shaping method provided by the present invention may also have the following characteristics: wherein the wall thickness of the heat-insulating sleeve in step S2 is 1-5 mm, and the wall thickness of the plastic film sleeve is 0-0.1 mm.

[0013] The nickel-titanium alloy wire shaping method provided by the present invention may also have the following characteristics: wherein, in step S3, the current density of the energized wire is 4-10A / mm 2 , the time does not exceed 100s.

[0014] The present invention also provides a nickel-titanium alloy wire having this feature, which is formed by a nickel-titanium alloy wire forming method.

[0015] The nickel-titanium alloy wire provided by the present invention may also have the following characteristics: the microstructure of the nickel-titanium alloy wire before shaping is composed of nanocrystals and amorphous materials, and the grain size of the nanocrystals does not exceed 100 nm.

[0016] The nickel-titanium alloy wire provided by the present invention may also have the following characteristics: wherein the microstructure of the nickel-titanium alloy wire after shaping is composed of nanocrystals, and the grain size of the nanocrystals does not exceed 100 nm.

[0017] The present invention also provides an application of nickel-titanium alloy wire in the preparation of wearable devices or medical components.

[0018] In the application of the nickel-titanium alloy wire provided by the present invention in the preparation of wearable devices or medical components, it can also have the following characteristics: wherein the nickel-titanium alloy wire covered with a heat-insulating sleeve and a plastic film sleeve is directly wrapped around the arm, and the nickel-titanium alloy wire is fixed to the arm with paper tape, and then energized and shaped with direct current.

[0019] Functions and Effects of the Invention

[0020] According to the nickel-titanium alloy wire, shaping method and application thereof involved in the present invention, the nickel-titanium alloy wire of the present invention is a microstructure of a composite of amorphous and nanocrystalline, which reduces the temperature required for shaping from the material itself, retains the nanocrystalline microstructure after shaping, and when power is turned on during shaping, the temperature is lower than 55°C, which will not cause harm to the human body, and can be shaped directly on the human body to improve the shaping effect. The wearable device or medical component prepared in this way is more ergonomic and can also be shaped according to the user's individual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1. The figure is a picture (a) of the application of nickel-titanium alloy wire in the preparation of wearable devices and a temperature measurement picture (b) of an infrared thermal imager in an embodiment of the present invention;

[0022] Figure 2The embodiment of the present invention is a shaping effect of the nickel-titanium wire on a human arm (a) and the nickel-titanium wire after shaping is put on the arm (b);

[0023] Figure 3 is an exploded view of a nickel-titanium wire shaping die in an embodiment of the present invention;

[0024] Figure 4 is a schematic structural diagram of the nickel-titanium wire shaping die in an embodiment of the present invention when power is supplied;

[0025] Figure 5 It is an infrared thermal imager temperature measurement diagram of a nanocrystalline (25%)-amorphous (75%) sample covered with a heat insulation cover and a plastic film cover in an embodiment of the present invention;

[0026] Figure 6 The infrared thermal imager temperature measurement diagram of the nanocrystalline (25%)-amorphous (75%) sample in the embodiment of the present invention without the heat insulation cover and the plastic film cover; and

[0027] Figure 7 The conventional sample without amorphous and the nanocrystalline (25%)-amorphous (75%) sample in the embodiment of the present invention are at a current density of 8.3A / mm 2 , Comparison of shaping effects after DC shaping for 30s. DETAILED DESCRIPTION

[0028] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically describe the nickel-titanium alloy wire, shaping method and application of the present invention, including Example 1, Comparative Example 1 and Comparative Example 2, wherein Comparative Examples 1 and 2 are mainly for illustrating the superiority of the method of this embodiment.

[0030] Example 1

[0031] A nickel-titanium alloy wire shaping method of this embodiment includes the following steps:

[0032] S1, drawing is performed before shaping, and the nickel-titanium alloy wire with a diameter of 1 mm is drawn to a diameter of 0.8 mm. The drawing process is as follows: the initial sample with a diameter of 1 mm is annealed with a 12A-600s DC current, and air-cooled; cold-drawn to 0.9 mm, the drawing speed is 50 mm / min, and the average drawing force is 280 N, and then annealed in a furnace at 300 degrees-8 min, and water quenched; cold-drawn to 0.8 mm, the drawing speed is 50 mm / min, and the average drawing force is 370 N. The microstructure of the nickel-titanium alloy after drawing is a composite of amorphous and nanocrystalline, in which the amorphous fraction accounts for 75% and the nanocrystalline fraction accounts for 25%;

[0033] S2, a heat-insulating sleeve and a plastic film sleeve are sequentially put on the surface of the nickel-titanium alloy wire, the heat-insulating sleeve material is silicon oxide nano-aerogel, the sleeve wall thickness is 1.5 mm, the inner diameter is 1 mm, and the plastic film material is a low-density polyethylene film with a thickness of 0.1 mm;

[0034] S3, directly wrapping the nickel-titanium alloy wire covered with the heat-insulating sleeve and the plastic film sleeve in step S2 around the arm, and energizing the nickel-titanium alloy wire with direct current at a current density of 8.3 A / mm 2 , time is 30s, for shaping, and then cooled to room temperature after power off. During the shaping process, the surface temperature of the plastic film sleeve is 48℃.

[0035] Figure 1 These are pictures of the application of nickel-titanium alloy wire in the preparation of wearable devices and temperature measurement pictures with an infrared thermal imager in an embodiment of the present invention. Figure 1 (a) The nickel-titanium alloy wire covered with a heat-insulating sleeve and a plastic film sleeve is directly wrapped around the arm and fixed with paper tape. Figure 1 (b) is powered at 8.3A / mm 2 , infrared temperature measurement diagram at a time of 30s. Figure 2 The figure is a shaping effect of the nickel-titanium wire on a human arm in an embodiment of the present invention (a) and the nickel-titanium wire after shaping is put on the arm (b). It can be seen that the nickel-titanium wire after shaping can better match the shape of the arm.

[0036] The drawing process in step S1 is a plastic deformation process of the nickel-titanium alloy. A large number of crystal defects are accumulated during the plastic deformation process, resulting in grain breakage and amorphization, thereby obtaining a nanocrystalline and amorphous composite microstructure.

[0037] like Figure 1-2 As shown, the application method of the above nickel-titanium alloy wire in preparing wearable devices or medical components is as follows:

[0038] Before performing step S3, the nickel-titanium alloy wire covered with a heat-insulating sleeve and a plastic film sleeve is directly wound around the arm or relevant parts of the human body, and then powered on for shaping according to step S3. After shaping is completed, the heat-insulating sleeve and the plastic film sleeve are removed to obtain a customized nickel-titanium alloy wire.

[0039] It should be pointed out that the realization of this process is the joint effect of two aspects. On the one hand, nanocrystalline and amorphous microstructures are required, and on the other hand, thermal insulation sleeves and plastic film sleeves are required.

[0040] Comparative Example 1

[0041] This comparative example is mainly to highlight the necessity of the heat-insulating sleeve and the plastic film sleeve. Based on the nickel-titanium alloy wire shaping method of Example 1, the step S2 of sequentially covering the nickel-titanium alloy wire with the heat-insulating sleeve and the plastic film sleeve is eliminated.

[0042] In order to illustrate the necessity of the heat-insulating sleeve and the plastic film sleeve, this example compares the temperature of putting on and taking off the heat-insulating sleeve and the plastic film sleeve. Since the surface temperature of the heat-insulating sleeve and the plastic film sleeve is high when they are taken off, they cannot be shaped on the human body, so a shaping mold is designed.

[0043] Figure 3 It is an exploded view of the nickel-titanium wire shaping mold in an embodiment of the present invention. Figure 4 It is a schematic structural diagram of the nickel-titanium wire shaping die in an embodiment of the present invention when power is supplied.

[0044] like Figure 3-4 As shown, the bottom of the nickel-titanium wire shaping mold 1 is an aluminum alloy base 110, and cross slide grooves 132 are respectively arranged on both sides of the aluminum alloy base, and a slider 131 is arranged inside the cross slide groove 132.

[0045] A ceramic lower plate 123 is fixed above the aluminum alloy base 110, and a first ceramic upper plate 121 and a second ceramic upper plate 122 are provided above the ceramic lower plate 123, wherein the second ceramic upper plate 122 is semi-arc-shaped and is fixed above the ceramic lower plate 123 by screws 140, and the shapes of the first ceramic upper plate 121 and the second ceramic upper plate 122 match each other, and the first ceramic upper plate 121 is fixed to the slider 131 by screws 140, so that the first ceramic upper plate 121 can move along the direction of the cross slide groove 132.

[0046] When in use, first move the first ceramic upper plate 121 so that there is a gap between the first ceramic upper plate 121 and the second ceramic upper plate 122, then place the shaped sample 150 in the gap, and then move the first ceramic upper plate 121 along the direction of the second ceramic upper plate 122 to squeeze the shaped sample 150 into an arc shape, and finally perform a power-on test.

[0047] In this embodiment, based on the nickel-titanium alloy wire shaping method of Example 1, step S2 of sequentially covering the surface of the nickel-titanium alloy wire with a heat-insulating sleeve and a plastic film sleeve is eliminated.

[0048] Figure 5 This is an infrared thermal imager temperature measurement diagram of a nanocrystalline (25%)-amorphous (75%) sample covered with a heat-insulating sleeve and a plastic film sleeve in an embodiment of the present invention. Figure 6 This is an infrared thermal imager temperature measurement diagram of a nanocrystalline (25%)-amorphous (75%) sample in an embodiment of the present invention without a heat-insulating sleeve and a plastic film sleeve.

[0049] like Figure 5-6 As shown in FIG. 1 , the heat-insulating sleeve and the plastic film sleeve are removed in this embodiment. At this time, the surface forming temperature of the nanocrystalline-amorphous sample is 250°C. Although this temperature is lower than the existing 400°C, it is still not in direct contact with the human body. Therefore, the heat-insulating sleeve and the plastic film sleeve are necessary, which makes the electric setting process (current density is 8.3A / mm 2 , time is 30s), the surface temperature of the plastic film sleeve drops to 48℃.

[0050] Comparative Example 2

[0051] This comparative example is mainly to highlight the necessity of amorphous and nanocrystalline composite microstructures. Based on the nickel-titanium alloy wire shaping method of Example 1, the drawing step of step S1 is eliminated, and conventional nanocrystalline nickel-titanium alloy wire without amorphous is selected.

[0052] Figure 7 The conventional sample without amorphous and the nanocrystalline (25%)-amorphous (75%) sample in the embodiment of the present invention are at a current density of 8.3A / mm 2 , Comparison of shaping effects after DC shaping for 30s.

[0053] from Figure 7 It can be found that nanocrystalline-amorphous samples can be well shaped. However, traditional nanocrystalline nickel-titanium alloys without amorphous materials have severe springback and cannot be shaped. This shows that traditional nickel-titanium alloy samples require a higher shaping temperature and are difficult to apply to personalized matching shaping for the human body.

[0054] Functions and Effects of the Embodiments

[0055] According to the nickel-titanium alloy wire, shaping method and application thereof involved in the present invention, the nickel-titanium alloy wire of the present invention is a composite microstructure of amorphous and nanocrystalline, and the temperature required for shaping is reduced from the material itself. At the same time, a heat-insulating sleeve and a plastic film sleeve are sequentially put on the surface of the nickel-titanium wire. When the power is turned on for shaping, the temperature is lower than 55°C, which will not cause harm to the human body. It can be shaped directly on the human body to improve the shaping effect. The wearable device or medical component prepared in this way is more ergonomic and can also be shaped according to the user's personalized matching. The microstructure of the nickel-titanium wire after shaping is nanocrystalline, and the grain size does not exceed 100nm, which is conducive to ensuring good performance.

[0056] Compared with the conventional nanocrystalline nickel-titanium alloy wire without amorphous materials, the nanocrystalline (25%)-amorphous (75%) sample of the present invention has a current density of 8.3A / mm 2 The shaping effect after DC shaping for 30s is good, with basically no rebound, which can better improve the equipment effect of wearable devices or medical components and better meet customized needs.

[0057] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for shaping nickel-titanium alloy wire, characterized in that: The steps include: S1, drawing is performed before shaping, and the microstructure of the nickel-titanium alloy after drawing is a composite of amorphous and nanocrystalline; S2, sequentially putting a heat-insulating sleeve and a plastic film sleeve on the surface of the nickel-titanium alloy wire; S3, using direct current to energize the nickel-titanium alloy wire for shaping, and cooling it to room temperature after power off. During the shaping process, the surface temperature of the plastic film sleeve is ≤55°C.

2. The method for shaping nickel-titanium alloy wire according to claim 1, characterized in that: in, The amorphous content in step S1 is ≥ 20%.

3. The method for shaping nickel-titanium alloy wire according to claim 1, characterized in that: in, The thermal insulation sleeve material in step S2 includes silicon dioxide nano-aerogel, porous vacuum silicon and glass fiber.

4. The method for shaping nickel-titanium alloy wire according to claim 3, characterized in that: in, The wall thickness of the heat-insulating sleeve in step S2 is 1-5 mm, and the wall thickness of the plastic film sleeve is 0-0.1 mm.

5. The method for shaping nickel-titanium alloy wire according to claim 1, characterized in that: in, In step S3, the current density of the energized current is 4-10A / mm 2 , the time does not exceed 100s.

6. The nickel-titanium alloy wire according to claim 1, characterized in that: The nickel-titanium alloy wire is shaped by the nickel-titanium alloy wire shaping method described in any one of claims 1 to 6.

7. The nickel-titanium alloy wire according to claim 1, characterized in that: The microstructure of the nickel-titanium alloy wire before shaping consists of nanocrystals and amorphous materials, and the grain size of the nanocrystals does not exceed 100 nm.

8. The nickel-titanium alloy wire according to claim 1, characterized in that: After shaping, the microstructure of the nickel-titanium wire is nanocrystalline, and the grain size does not exceed 100nm.

9. Use of the nickel-titanium alloy wire as described in claims 6-8 in the preparation of wearable devices or medical components.

10. The use of the nickel-titanium alloy wire according to claim 9 in preparing wearable devices or medical components, characterized in that: The nickel-titanium alloy wire covered with the heat-insulating sleeve and the plastic film sleeve is directly wound around the arm, and the nickel-titanium alloy wire is fixed to the arm using paper tape, and then energized and shaped using direct current.

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