Method for quick processing iron based shape memory alloy under large current impulse

A technology of memory alloy and fast pulse, which is applied in the field of shape memory alloy to achieve the effect of improving the effect, simplifying the processing technology and shortening the processing time

Inactive Publication Date: 2012-03-07
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there are few reports on the rapid processing of iron-based shape memory alloys using high-current pulses, especially the use of high-current pulses to act on deformed iron-based shape memory alloys to promote the rapid precipitation of the second phase, thereby improving the shape memory effect of the alloy. Not yet reported

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  • Method for quick processing iron based shape memory alloy under large current impulse
  • Method for quick processing iron based shape memory alloy under large current impulse

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Experimental program
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Effect test

Embodiment 1

[0020] According to the designed composition formula Mn30%, Si3%, Cr7%, Ni4%, C0.2%, Nb2% (the balance is iron, both are mass percentages), using industrial pure iron, metal manganese, metal silicon, metal chromium, Electrolytic nickel, graphite, and ferroniobium are used as raw materials, melted in an induction furnace, and then cast to obtain an ingot. The ingot size is φ78×160mm and weighs 5.5Kg. In order to eliminate the compositional inhomogeneity of the ingot, the ingot is homogenized and annealed at ~1100°C for 15 hours. After the surface scale is removed, it is hot-forged into a Φ15mm round bar at the initial forging temperature of 1100°C. Still at the initial forging temperature of 1100°C, the wire material of Φ3.5mm is formed by three rotary hammers. The Φ3.5mm wire is drawn into Φ1.5mm wire through 8 cold drawing (intermediate annealing process is 1273K×10min). Cut 20 wires with a length of 140 mm, put them in a straight pipe and keep them warm for 30 minutes at 11...

Embodiment 2

[0022] According to the designed ingredient formula, Mn is 14%, Si is 5%, Cr is 12%, Ni is 6%, C is 0.01%, and Nb is 0.1% (the balance is iron, which are all mass percentages). Pure iron, metal manganese, metal silicon, metal chromium, electrolytic nickel, and graphite are used as raw materials, melted in an induction furnace, and then poured to obtain an ingot. The ingot size is φ78×155mm and weighs 5.4Kg. In order to eliminate the compositional inhomogeneity of the ingot, the ingot is homogenized and annealed at ~1100°C for 15 hours. After the surface scale is removed, it is hot-forged into a Φ15mm round bar at the initial forging temperature of 1100°C. Still at the initial forging temperature of 1100°C, the wire material of Φ3.5mm is formed by three rotary hammers. The Φ3.5mm wire is drawn into Φ1.5mm wire through 8 cold drawing (intermediate annealing process is 1273K×10min). Cut 20 wires with a length of 140 mm, put them in a straight pipe and keep them warm for 30 minut...

Embodiment 3

[0024] According to the designed ingredient formula, Mn is 17%, Si is 7%, Cr is 8%, Ni is 5%, C is 0.1%, and Nb is 1% (the balance is iron, which are all mass percentages). Pure iron, metal manganese, metal silicon, metal chromium, electrolytic nickel, graphite, and ferroniobium are used as raw materials, melted in an induction furnace, and then poured to obtain an ingot. The ingot size is φ78×165mm and weighs 5.6Kg. In order to eliminate the compositional inhomogeneity of the ingot, the ingot is homogenized and annealed at ~1100°C for 15 hours. After the surface scale is removed, it is hot-forged into a Φ15mm round bar at the initial forging temperature of 1100°C. Still at the initial forging temperature of 1100°C, the wire material of Φ3.5mm is formed by three rotary hammers. The Φ3.5mm wire is drawn into Φ1.5mm wire through 8 cold drawing (intermediate annealing process is 1273K×10min). Cut 20 wires with a length of 140 mm, put them in a straight pipe and keep them warm fo...

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Abstract

This invention discloses a method for rapidly treating iron-based shape memory alloy via high-current pulse generated by a remote-control (RC) charge / discharge apparatus. The method comprises: pre-defoaming the iron-based shape memory alloy, and treating by high-current pulse. By the method, a large amount of the second phase of the iron-based shape memory alloy can be rapidly precipitated within60 s. In the method, the current density, the width, the frequency and the time of the pulse can be controlled by regulating the capacitance (10-10000 mu.F), the voltage (50-600 V) and the pulse frequency (0.5-500 Hz) of the RC charge / discharge apparatus. The treated iron-based shape memory alloy has a shape recovery rate above 80% (when bending deformation amount is 5%) and a recoverable deformation amount above 4.0%. The RC charge / discharge apparatus used in the method has simple structure and convenient maintenance. The method has such advantages as short treatment period and high efficiency.

Description

technical field [0001] The invention relates to the field of shape memory alloys, in particular to a method for rapidly processing iron-based shape memory alloys with large current pulses. The iron-based shape memory alloy prepared by the method has high shape recovery rate and recoverable deformation, and has the advantages of simple manufacturing process, low cost and short processing time. It can be applied in the fields of driving mechanism, fastening connection elements such as pipe joints and sensing elements. Background technique [0002] The shape memory effect means that a deformed material can fully or partially return to its original undeformed shape when heated above a certain temperature. Alloys with this effect are called shape memory alloys, which are a new type of functional material that integrates perception and actuation. Iron-based shape memory alloys are not only cheap, high strength, easy to process, but also have a high phase transition point and lar...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/58C22C30/00C21D10/00C22F3/00
Inventor 李宁杨世洲文玉华刘文博张伟
Owner SICHUAN UNIV
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