Nickel-titanium shape memory alloy micro-wire surface machining process

A memory alloy and surface processing technology, applied in metal processing equipment, metal material coating technology, metal wire drawing, etc., can solve problems such as difficult to accurately control penetration thickness, functional attenuation of shape memory alloy microwires, etc., and achieve clear technical methods Simple, easy to promote, simple and controllable effect

Active Publication Date: 2020-09-08
常州艾易泰合金科技有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] For shape memory alloy microwires with extremely small diameters (less than 100 μm), electrochemical polishing is likely to greatly increase the hydrogen content of the material and cause brittleness; while surface nitriding is extremely difficult to precisely control the penetration thickness, and poor control may easily lead to shape loss. Functional Attenuation of Memory Alloy Microwires
Therefore, there is no mature process to suppress the surface crack initiation of nickel-titanium shape memory alloy microwires.

Method used

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  • Nickel-titanium shape memory alloy micro-wire surface machining process
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  • Nickel-titanium shape memory alloy micro-wire surface machining process

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Experimental program
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Effect test

Embodiment 1

[0037] The nickel-titanium shape-memory alloy microwire 3 with a diameter of 25 μm was selected. The actual diameter of the nickel-titanium shape-memory alloy microwire was measured by scanning electron microscope to be 25.07 μm, and the initial grain size was 80 nm, which was recorded as the first microwire; a diamond wire drawing die was selected 3 groups, the outlet apertures are 24.5μm, 24μm and 23.5μm respectively, and the cone angle is 25°. Oil lubricating fluid is used for spray cooling drawing. After 3 consecutive passes of drawing, the second microfilament is obtained. Microstructural characterization of the second microfilament, as figure 1 As shown, it is determined that there is an amorphous layer 1 with a thickness of about 60nm on the surface of the second microwire; then the second microwire is plasma nitrided in a tube furnace, the nitriding temperature is 350°C, and the time is 2 minutes. During the nitriding process, The tension at both ends of the second mic...

Embodiment 2

[0039] The nickel-titanium shape memory alloy microwire 3 with a diameter of 50 μm was selected. The actual diameter of the nickel-titanium shape memory alloy microwire was measured by scanning electron microscope to be 50.10 μm, and the initial grain size was 100 nm, which was recorded as the first microwire; a diamond wire drawing die was selected Group 2, the outlet apertures were 48.5 μm and 47.5 μm, and the cone angles were both 24°. Oily lubricating fluid was used for spray cooling and drawing. After two consecutive drawing passes, the second microfilament was obtained. The microstructure of the second microwire was characterized, and it was determined that there was an amorphous layer 1 with a thickness of about 160 nm on the surface of the second microwire; then, the second microwire was plasma nitriding in a tube furnace, the nitriding temperature was 450°C, and the time was 3 minutes. During the nitriding process, the tension at both ends of the second microfilament w...

Embodiment 3

[0041] The nickel-titanium shape-memory alloy microwire 3 with a diameter of 30 μm was selected. The actual diameter of the nickel-titanium shape-memory alloy microwire was measured by scanning electron microscope to be 30.15 μm, and the initial grain size was 65 nm, which was recorded as the first microwire; a diamond wire drawing die was selected 3 groups, the outlet apertures are 29.4μm, 28.8μm and 28.2μm, and the cone angle is 28°. Oil lubricating fluid is used for spray cooling drawing. After 3 consecutive passes of drawing, the second microfilament is obtained , perform microstructural characterization on the second microwire, and confirm that there is an amorphous layer 1 with a thickness of about 120 nm on the surface of the second microwire; 2min, during the nitriding process, the tension at both ends of the second microwire was maintained at 220MPa, and the third microwire was obtained, and the surface XPS analysis and micro-area XRD analysis were carried out on the t...

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Abstract

The invention provides a nickel-titanium shape memory alloy micro-wire surface machining process and relates to the technical field of material machining. Nitriding treatment is conducted after repeated cold drawing process treatment is conducted on a preprocessed nickel-titanium shape memory alloy micro-wire, so that the nickel-titanium shape memory alloy micro-wire long in fatigue life are obtained. Cold drawing treatment is conducted on the nickel-titanium shape memory alloy micro-wire through a wire-drawing die, an amorphous layer can be formed on the surface of the micro-wire in an accurate control manner, nitriding treatment is conducted on this basis, crystallization of the amorphous layer can be achieved, and a hardening layer with the thickness being accurate and controllable is formed. The nickel-titanium shape memory alloy micro-wire surface machining process is suitable for industrially, easily and controllably machining the hardening layer on the surface of the nickel-titanium shape memory alloy micro-wire, generation of surface fatigue cracks of the nickel-titanium shape memory alloy micro-wire is effectively restrained, the fatigue life of the shape memory alloy micro-wire is greatly prolonged, and the own shape memory function of the wire cannot be damaged.

Description

technical field [0001] The invention relates to the field of material processing, in particular to a process for processing the surface of nickel-titanium shape memory alloy microwires. Background technique [0002] Shape memory alloy is an advanced intelligent material with multi-functionality such as superelasticity, shape memory effect, damping and displacement sensing, etc. It has great application potential in the fields of medical equipment, aerospace, microelectronics and robots. In actual use, the challenges of shape memory alloys lie in the complexity of the control model, low driving frequency and fatigue life. Shape memory alloys are known for their large recoverable strain and output stress in the intelligent driving material system, and the main application form is wire or film. In certain application areas, such as microelectronic devices or linear motor actuators, high demands are placed on fatigue performance. The fatigue performance of shape memory alloys ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21C1/04B21C19/00C22F1/00C22F1/10C23C8/36
CPCB21C1/04B21C19/00C22F1/006C22F1/10C23C8/36
Inventor 占静玲丁希可蔡正午
Owner 常州艾易泰合金科技有限公司
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