Method for regulating magnetic domain of FeGa magnetostrictive alloy by using unidirectional solidification stress

A technology of directional solidification and alloying, applied in the direction of self-solidification method, chemical instruments and methods, single crystal growth, etc., can solve the problems such as being unsuitable for processing large-size samples, high requirements for heat treatment equipment, uneven magnetic field distribution, etc., to achieve comprehensive use The effect of good performance, convenient operation and simple process equipment

Active Publication Date: 2018-12-18
BEIHANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the need to apply a strong magnetic field, this method has high requirements for heat treatment equipment, and because the magnetic field is not uniformly distributed in a large range, it is not suitable for processing large-scale samples.
[0006] In addition to magnetic field heat treatment, stress annealing is currently used to improve the distribution of magnetic domains, but there are also some shortcomings, such as the need for additional pressurized devices, and a huge load is required to process large-sized samples.

Method used

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  • Method for regulating magnetic domain of FeGa magnetostrictive alloy by using unidirectional solidification stress
  • Method for regulating magnetic domain of FeGa magnetostrictive alloy by using unidirectional solidification stress
  • Method for regulating magnetic domain of FeGa magnetostrictive alloy by using unidirectional solidification stress

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Experimental program
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Embodiment 1

[0033] The steps used in this embodiment are as follows:

[0034] 1. Ingredients

[0035] The purity of the selected raw materials Fe and Ga are both 99.99wt%, and in order to prevent Ga element from burning during the smelting process, the Fe 81 Ga 19 2wt% Ga is added on the basis of the composition. Specifically, 1547.1 g of Fe and 461.8 g of Ga were weighed for use. Fe must be ultrasonically cleaned with absolute ethanol before mixing, and dried under vacuum to remove oil on the surface.

[0036] 2. Preparation of master alloy ingot

[0037] Put the above-mentioned weighed raw materials Fe and Ga into the crucible of the vacuum non-consumable arc smelting furnace. When placing, it is necessary to place the easily burned Ga element on the bottom of the crucible, and the non-burnable Fe element on the crucible.

[0038] Vacuum non-consumable arc melting furnace to 5.0×10 -2 After Pa, fill the furnace body with high-purity argon, the volume percentage (purity) of argon is above 99.99%...

Embodiment 2

[0051] 1. The batching, the preparation of the master alloy ingot and the preparation of the master alloy rod of this embodiment are the same as those of the first embodiment.

[0052] 2. In the step of preparing FeGa alloy by directional solidification, the graphite heater is heated to 800°C at a heating rate of 30°C / min, and after holding for 5 minutes, the graphite heating body is heated to 1625°C at a heating rate of 25°C / min, and then holding for another 30 minutes. . The growth rate was controlled to 5mm / h, and the corundum crucible was smoothly drawn down into the liquid alloy for directional solidification. After the directional growth is completed, the temperature of the directional furnace is lowered to room temperature and then the grown FeGa alloy is taken out.

[0053] 3. The obtained FeGa alloy is oriented in the [001] direction, the magnetic domains are arranged perpendicular to the growth direction, and the width is 70-120μm; the magnetostriction coefficient of the...

Embodiment 3

[0055] 1. The batching, the preparation of the master alloy ingot and the preparation of the master alloy rod of this embodiment are the same as those of the first embodiment.

[0056] 2. In the step of preparing FeGa alloy by directional solidification, the graphite heater is heated to 800°C at a heating rate of 30°C / min, and after holding for 5 minutes, the graphite heating body is heated to 1625°C at a heating rate of 25°C / min, and then holding for another 30 minutes. . The growth rate was controlled to 50mm / h, and the corundum crucible was smoothly drawn down into the liquid alloy for directional solidification. After the directional growth is completed, the temperature of the directional furnace is lowered to room temperature and then the grown FeGa alloy is taken out.

[0057] 3. The obtained FeGa alloy is oriented in the [001] direction, the magnetic domains are arranged perpendicular to the growth direction, and the width is 60-90 μm; the magnetostriction coefficient of th...

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Abstract

The invention discloses a method for regulating the magnetic domain of a FeGa magnetostrictive alloy by using unidirectional solidification stress. The method is a liquid metal cooling Bridgman method. According to the invention, unidirectional thermal stress generated by unidirectional heat conduction parallel to a growth direction in the directional solidification process of the liquid metal cooling Bridgman method is utilized to allow initial magnetic domains in the FeGa alloy to be arrayed along a direction perpendicular to the growth direction, so a saturation magnetostriction value of 300 to 320 ppm can be obtained without pre-compressive stress. The nominal composition of the FeGa alloy is Fe100-xGax, wherein x is no less than 17 and no more than 20. After melting of Fe and Ga proportioned according to composition requirements into a master alloy ingot and the master alloy ingot is cast into a master alloy rod, the FeGa master alloy rod is placed in directional solidification equipment; the directional solidification equipment is vacuumized and filled with protection gas; the mother alloy rod is completely melted by heating; then a molten material is drawn into a liquid metal coolant for directional solidification; and a temperature gradient is controlled to be 5*10<4>-9*10<4> K / m, and a growth rate is controlled to be 1 to 100 mm / h.

Description

Technical field [0001] The invention relates to a method for regulating FeGa alloy magnetic domains by using unidirectional solidification stress, in particular to a method for regulating FeGa alloy magnetic domains by using unidirectional thermal stress parallel to the growth direction during the directional solidification process of liquid metal cooling crucible descending method , Belongs to the field of crystal growth. Background technique [0002] Magnetostrictive materials are an important type of magnetically driven smart materials. The length and volume of the material can be reversibly transformed under the action of an external magnetic field, which has the effect of transforming magnetism and force. The magnetostrictive material has the advantages of high magneto-force energy conversion efficiency, and the prepared magnetostrictive device has strong reliability and simple driving mode. Magnetostrictive materials and devices are used in medical and health (medical magn...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B11/02C30B29/52
CPCC30B11/02C30B29/52
Inventor 王敬民陈艺骏蒋成保刘敬华张天丽
Owner BEIHANG UNIV
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