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Magnetic and heating treatment method to improve magnetically driven reversible strain property of polycrystalline Ni2 MnGa

A magnetic drive and strain variable technology, applied in the direction of material selection for magnetostrictive devices, inorganic material magnetism, device material selection, etc., can solve the problems of misorientation of martensitic twins

Inactive Publication Date: 2003-11-05
EMERSON ELECTRIC (CHINA) HLDG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the disordered orientation of the parent phase grains and the martensitic twin variants induced by pure heat in the polycrystalline material, the magnetically induced macroscopic strain is only 10 -4 order of magnitude (that is, hundreds of ppm); even if the parent phase is columnar crystal (parent phase texture) through directional solidification, it can only reach 120×10 -6 and up to 0.30%

Method used

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  • Magnetic and heating treatment method to improve magnetically driven reversible strain property of polycrystalline Ni2 MnGa
  • Magnetic and heating treatment method to improve magnetically driven reversible strain property of polycrystalline Ni2 MnGa
  • Magnetic and heating treatment method to improve magnetically driven reversible strain property of polycrystalline Ni2 MnGa

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Embodiment 1

[0026] Improvement of polycrystalline Ni by using magnetic field heat treatment according to the present invention 2 A method for magnetically driving reversible strain of MnGa, the method comprising the following steps:

[0027] a) Preparation of Ni by non-stoichiometry according to the chemical formula 2 MnGa alloy containing 52at% Ni, 25at% Mn and 23at% Ga;

[0028] b) placing Ni, Mn and Ga raw materials of high-purity elements in an electric arc furnace, and performing repeated smelting under an argon protective atmosphere to produce a polycrystalline ingot;

[0029] c) performing homogenization annealing treatment on the above-mentioned polycrystalline ingot, the annealing temperature is 1173K, and the time is 3 days;

[0030] d) The homogenized heat-treated polycrystalline ingot is made into 2×4×8mm 3 Ni 52 mn 25 Ga 23 sample, placed in the figure 1 The magnetic yoke-permanent magnet assembly shown is subjected to magnetic field heat treatment, the magnetic field ...

Embodiment 2

[0037] Improvement of Polycrystalline Ni by Magnetic Field Heat Treatment 2 The method of the magnetic drive reversible strain of MnGa, this method adopts the same step as embodiment 1, just Ni 52 mn 25 Ga 23 The magnetic field heat treatment of the sample is cooled by water quenching (W).

[0038] In the method step of this embodiment, the same sample is subjected to the same heat treatment in the magnetic field of zero magnetic field H=0 and H 0.7T, which are respectively expressed as:

[0039] T 1 W-0 means that the sample is water quenched under the condition of H=0 (0) after being kept at 413K for 30 minutes.

[0040] T i W-L means that after the sample is kept at 413K for 30 minutes, it is longitudinally treated in a magnetic field under the condition of H≈0.7T (L) water quenching.

[0041] T 1 W-T means that after the sample is kept at 413K for 30 minutes, it is water-quenched under the condition of H≈0.7T under the condition of magnetic field transverse treatmen...

Embodiment 3

[0051] As the embodiment of water quenching (W) and air-cooling (A) method, use the same step and material as embodiment 1 and 2, just the heat treatment heating temperature of sample piece after annealing adopts 348K (T 2 ) (higher than the end temperature of reverse phase transition A f ), the same sample is subjected to the same heat treatment in the longitudinal (L) or transverse (T) magnetic field of zero magnetic field H=0 and H≈0.7T, air cooling or water quenching are respectively expressed as: T 2 A-L, T 2 A-0, T 2 W-L, T 2 W-0, T 2 A-T, T 2 A-0, T 2 W-T and T 2 W-0. In Example 3, the magnetically induced strain of each sample was measured in the electromagnet with a variable magnetic field H=0-1T along the longitudinal direction of the sample. The test results are listed in Table 2. Correspondingly, according to the measured data of Table 2, the comparison chart of magnetically induced strain is shown in Figure 4 second half of .

[0052] Applied m...

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Abstract

The magnetic field heating treatment to improve magnetically driven reversible strain property of polycrystalline Ni2MnGa includes the following steps: preparing Ni2MnGa alloy in nonstoichiometeric ratio with Ni content of 50.3-53.0 at% and Mn / Ga ratio 1.05-1.15; electric arc smelting with high purity element Ni, Mn and Ga material under Ar protection to produce polycrystalline ingot; homogenizing annealing treatment of the polycrystalline ingot at 1100-1200 K for 1-3 days; heat treatment in magnetic field of strength H 0.7T, temperature 240-350 K or 360-460 K for 20-30 min and final air cooling or water quenching. The said process of the present invention raises the magnetically driven reversible strain amount of polycrystalline Ni2MnGa by about 17 %.

Description

technical field [0001] The present invention relates to a kind of Ni that can produce magneto-controlled shape memory effect 2 MnGa functional material, more specifically, relates to a polycrystalline Ni that can be improved by magnetic field heat treatment 2 MnGa method for magnetically actuated reversible strain. Background technique [0002] As a new type of functional material, shape memory alloy (SMA) can undergo shape recovery under certain conditions, resulting in macroscopic strain and restoring force. Since Buehler and others in the United States first discovered the shape memory effect (SME) in NiTi alloy in 1963, great progress has been made in basic research and development and application, and it has been used in aviation, aerospace, medical, engineering and daily life. widely used. Although traditional shape memory alloys such as NiTi, Cu-based, and Fe-based alloys have large recoverable strain and large restoring force, their response frequency is very low ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C19/03H10N35/85
CPCC22C19/03H10N35/85
Inventor 徐祖耀陈世朴赵容斌钱明
Owner EMERSON ELECTRIC (CHINA) HLDG CO LTD
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