A COVGA-based Heusler alloy realizing magnetic field-driven metamagnetic reverse martensitic transformation

A martensitic transformation, magnetic field driven technology, applied in the field of Heusler alloys, can solve the problems of poor mechanical properties, limited magnetocaloric materials, brittleness, etc. Effect

Active Publication Date: 2021-11-09
JIANGXI UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the martensitic transformation is usually accompanied by many physical phenomena. In addition, no magnetic field-driven magnetic reverse martensitic transformation has been reported in CoVGa-based Heusler alloys.
[0004] In addition, the reason why many materials with excellent magnetocaloric properties in the past have not been applied to solid-state refrigeration soon is mainly because their mechanical properties are too poor, fragile, low strength, poor machinability, etc., which greatly limit the magnetic field. Thermal materials into practical applications

Method used

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  • A COVGA-based Heusler alloy realizing magnetic field-driven metamagnetic reverse martensitic transformation
  • A COVGA-based Heusler alloy realizing magnetic field-driven metamagnetic reverse martensitic transformation
  • A COVGA-based Heusler alloy realizing magnetic field-driven metamagnetic reverse martensitic transformation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Example 1 In order to satisfy the first general chemical formula Co of the alloy 50-x Fe x V 35 Ga 15 , x takes 1.

[0040] This embodiment is an alloy Co with a magnetically variable martensitic transformation 49 Fe 1 V 35 Ga 15 , according to the stoichiometric ratio to calculate the required mass of Co, Fe, V, Ga elements for batching, it needs to be accurate to 0.1mg ~ 0.01mg, and the purity of the metal elements is above 99.95%. Put the prepared raw materials into the water-cooled copper crucible arc melting furnace, and pump the vacuum to 5×10 -3 Above Pa, fill with argon gas with a purity of 99.999% at 1 atmospheric pressure for arc melting.

[0041] For the first smelting, use 23A current to melt the metal. When you see the metal liquid flowing in the crucible, turn over the block sample smelted in the first smelting, slightly increase the current to 40A and smelt it 4 times, and you can get Co 49 Fe 1 V 35 Ga 15 Alloy ingots; put part of the alloy i...

Embodiment 2

[0042] Example 2 The first general chemical formula of the alloy Co 50-x Fe x V 35 Ga 15 , x takes 5.

[0043] This embodiment is an alloy Co with magnetic field-driven metamagnetic martensitic transformation 45 Fe 5 V 35 Ga 15 , the specific preparation method of the bulk alloy is almost the same as the preparation process of Example 1, the difference is that part of the Co 45 Fe 5 V 35 Ga 15 The alloy ingot is put into a quartz tube with an inner diameter of 10 mm, and then the quartz tube is placed in a high vacuum belt furnace, and the furnace cavity is evacuated to 10 mm. -4 Pa, 0.5 atmospheric pressure of argon gas is introduced, the ingot is melted into a liquid state through high-frequency induction heating, and then sprayed onto the high-speed rotating copper rod through the small hole at the bottom of the quartz tube, and the speed of the copper rod is 10-50m / s , to obtain a fast-quenched strip sample; put the strip sample into a quartz tube with an inner ...

Embodiment 3

[0044] Example 3 The first general chemical formula of the alloy Co 50-x Fe x V 35 Ga 15 , x takes 4.

[0045] This embodiment is an alloy Co with a magnetic field-driven metamagnetic martensitic transformation 46 Fe 4 V 35 Ga 15 , the specific preparation method of the sample is the same as the preparation process of Example 1, the only difference is that according to Co 46 Fe 4 V 35 Ga 15 The stoichiometric ratio is used to calculate the mass of the required Co, Fe, V, and Ga elements for batching; the annealing temperature is 1200 ° C, and the time is 24 hours. in Co 46 Fe 4 V 35 Ga 15 The temperature-driven severe metamagnetic martensitic phase transformation is obtained in the alloy sample, and phase transformation retardation occurs at low temperature. The thermomagnetic curve of the alloy sample under a 0.1T magnetic field is shown in the attached figure 2 shown. It can be seen that the alloy undergoes a severe martensitic transformation between 125-160...

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Abstract

The invention provides a CoVGa-based Heusler alloy that realizes magnetic field-driven variable magnetic reverse martensitic phase transformation, and its chemical formula is Co a‑ x Fe x V b‑15 Ga 15 ; Wherein, a+b=100, 50≤a≤52, 48≤b≤50, 1≤x≤6, a, b, x single group or combination represent atomic percentage content. The alloy has the characteristics of high strength, high hardness, high corrosion resistance, easy processing and forming, and temperature (magnetic field) driven magnetic reverse martensitic phase transformation. Alloys can be widely used in magnetic memory, solid-state refrigeration devices, magnetic drives, magnetic sensitive components, thermomagnetic-electric conversion and other fields.

Description

technical field [0001] The invention relates to a CoVGa-based Heusler alloy that realizes magnetic field-driven reverse martensitic phase transformation, and in particular to a Heusler alloy that has high strength, high hardness and high corrosion resistance and is capable of undergoing variable magnetic reverse martensitic transformation through the substitution of Fe elements. Heusler alloy with martensitic transformation. Background technique [0002] Heusler compounds are a special class of materials between compounds and alloys, combining the properties of compounds and alloys. Heusler compounds form a chemically stable covalent lattice inside, which can be replaced by different elements at a single lattice site. The Heusler structure can be divided into full structure (X 2 YZ) and semi-Heusler structure (XYZ), where X and Y are transition group metal elements, and z is the main group element. The structural changes and the diversity of elements in Heusler alloys make...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C19/07C22C30/00C22C1/02C22F1/02C22F1/10
CPCC22C1/02C22C19/07C22C30/00C22F1/02C22F1/10
Inventor 马胜灿刘凯韩幸奇俞堃钟震晨唐云志
Owner JIANGXI UNIV OF SCI & TECH
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