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Magnetic material with bidirectional shape memory effect and single-crystal producing method thereof

A technology of memory effect and magnetic materials, applied in the field of shape memory materials, can solve the problems of high brittleness of parent phase and low phase transition temperature, etc.

Inactive Publication Date: 2005-04-27
INST OF PHYSICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] For the above problems, the object of the present invention is to provide a magnetic material with two-way shape memory effect, which overcomes the existing ferromagnetic shape memory material Ni 2 The disadvantages of MnGa's Curie temperature, low phase transition temperature, and high brittleness of the parent phase make devices made of this material have excellent performance.

Method used

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  • Magnetic material with bidirectional shape memory effect and single-crystal producing method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] The preparation composition is: Mn 2 NiGa is a magnetic alloy with magnetically induced high strain and shape memory effect. It is heated by radio frequency with a growth parameter of 245 kHz, and argon with a positive pressure of 0.01 to 1 MPa is used as a protective gas. In a magnetic levitation cold crucible, the heating power is 20 Kilowatt, its preparation method is carried out according to the following specific steps:

[0023] (1) Weighing Mn39.19 grams, Ni20.94 grams and Ga24.87 grams with a purity of 99.9% respectively;

[0024] (2) Put the weighed material into the crucible, heat it to 1230°C to melt, keep it for 10-30 minutes, and the synthetic composition is Mn 2 The raw material of NiGa weighs 85 grams in total;

[0025] (3) Use Mn of 2×2×7mm size 2 NiGa[001] oriented single crystal is used as seed crystal to grow single crystal;

[0026] During the growth process, the rotation rate of the seed rod is 30 rpm, and the pulling growth rate is 30mm / hour;

...

Embodiment 2

[0031] The preparation composition is: Mn 45 Ni 30 Ga 25 A magnetic alloy with magnetically induced high strain and shape memory effect; the difference is that in a quartz crucible, it is grown by resistance heating, except that the rotation rate of the seed rod is 20 revolutions / minute, and the pulling growth rate is 10mm / hour , all the other are with embodiment 1, and its phase transition temperature and Curie temperature are shown in Table 1. Measure the strain of its shape memory effect, and obtain the characteristic curve whose shape is shown in the accompanying drawing, and its values ​​are shown in Table 3.

Embodiment 3

[0033] The preparation composition is: Mn 40 Ni 35 Ga 25 A magnetic alloy with magnetically induced high strain and shape memory effect; except that the rotation rate of the seed rod is 10 rpm and the pulling growth rate is 50 mm / hour, all the other are the same as in Example 1, its phase transition temperature and Curie temperature See Table 1. Measure the strain of its shape memory effect, and obtain the characteristic curve whose shape is shown in the accompanying drawing, and its values ​​are shown in Table 3.

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Abstract

The present invention discloses one kind of magnetic material with bi-directional shape memory effect and its monocrystal preparing process. The magnetic monocrystal material has the chemical expression of MnxNiyGaz, where x is 37-55, y is 20-38, z is 20-30, x+y+z=100, x, y and z are atom percentage content. The monocrystal preparing process includes setting prepared material in crucible and Czochralski process of growing the magnet MnxNiyGaz monocrystal. The magnetic monocrystal material has its martensitic transformation temperature regulated via altering the Mn, Ni and Ga ratio, and may have martensitic starting point regulated in 36-350 K and Curie temperature in 140-330 deg.c as requirement. In addition, the present invention uses conventional equipment, has low cost and is easy industrial application.

Description

technical field [0001] The invention relates to a shape memory material, in particular to MnNiGa magnetic material with ferromagnetism and two-way shape memory effect and its single crystal preparation method. Background technique [0002] Common shape memory alloys have a crystal structure (hereinafter referred to as the parent phase) at a relatively high temperature, and spontaneously change into another crystal structure at a relatively low temperature, generally called a martensitic phase. When cooling from a higher temperature to a lower temperature, the material transforms from the parent phase to the martensitic phase, which is called a martensitic transformation. Conversely, by heating the material from relatively low temperatures, the alloy undergoes a transformation from the martensitic phase to the parent phase, and this opposite phase transformation is called reverse martensitic transformation. Generally, the start point and end point of martensitic transformati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C22/00C22C32/00C30B15/00C30B29/52H01F1/047
Inventor 刘国栋柳祝红代学芳朱志永陈京兰吴光恒
Owner INST OF PHYSICS - CHINESE ACAD OF SCI
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