A method of controlling the magnetic domain of fega magnetostrictive alloy by 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: 2019-04-09
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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  • A method of controlling the magnetic domain of fega magnetostrictive alloy by unidirectional solidification stress
  • A method of controlling the magnetic domain of fega magnetostrictive alloy by unidirectional solidification stress
  • A method of controlling the magnetic domain of fega magnetostrictive alloy by unidirectional solidification stress

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Embodiment 1

[0033] The steps adopted 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 the Ga element from burning during the smelting process, the Fe 81 Ga 19 2wt% Ga was added on the basis of the composition. Specifically, 1547.1 g of Fe and 461.8 g of Ga were weighed for use. Before batching, Fe must be ultrasonically cleaned with absolute ethanol and dried under vacuum to remove the 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 melting furnace. When placing it, it is necessary to place the Ga element that is easy to burn at the bottom of the crucible, and the Fe element that is not easy to burn at the top of the crucible.

[0038] Vacuumize the vacuum non-consumable arc melting furnace to 5.0×10 -2 After Pa, fill the furnace body with ...

Embodiment 2

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

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

[0053] 3. The orientation of the obtained FeGa alloy is the [001] direction, the magnetic domains are arranged perpendicular to the growth direction, and the width is 70-120 μm; the magnetostriction coefficient of the FeGa alloy is 305ppm u...

Embodiment 3

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

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

[0057] 3. The orientation of the obtained FeGa alloy is the [001] direction, the magnetic domains are arranged perpendicular to the growth direction, and the width is 60-90 μm; the magnetostriction coefficient of the FeGa alloy is 311ppm u...

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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, it relates to a method for regulating FeGa alloy magnetic domains by using unidirectional thermal stress parallel to the growth direction in the directional solidification process of liquid metal cooling crucible drop method , belonging to the field of crystal growth. Background technique [0002] Magnetostrictive materials are an important class of magnetically driven smart materials. The length and volume of the material can undergo reversible changes under the action of an external magnetic field, achieving the effect of magnetism and force conversion. The magnetostrictive material has the advantages of high magnetic-force energy conversion efficiency, and the prepared magnetostrictive device has high reliability and simple driving mode. Magnetostrictive materials and devices are used in medical and health (medi...

Claims

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Application Information

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Patent Type & Authority Patents(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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