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Method for realizing giant negative thermal expansion of wide temperature area in MnCoGe base alloy

A technology with negative thermal expansion and wide temperature range, applied in the direction of nanotechnology, can solve the problem of few MnCoGe-based alloys, and achieve the effect of simple and convenient preparation method, less energy consumption and low preparation cost

Active Publication Date: 2018-07-20
JIANGXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It can be seen that the lattice volume ratio of the orthorhombic TiNiSi phase is higher than that of the hexagonal Ni 2 The lattice volume of the In phase is smaller, so MnCoGe-based phase change alloys have negative thermal expansion when the structural phase transition occurs. However, MnCoGe-based alloys have rarely been studied as negative thermal expansion materials until now.

Method used

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  • Method for realizing giant negative thermal expansion of wide temperature area in MnCoGe base alloy
  • Method for realizing giant negative thermal expansion of wide temperature area in MnCoGe base alloy
  • Method for realizing giant negative thermal expansion of wide temperature area in MnCoGe base alloy

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Alloys are designed according to principle, specifically Mn 0.965 co 1.035 Ge, the preparation steps are as follows:

[0025] S1. Dosing: According to the stoichiometric ratio, calculate the mass of the required Mn, Co, and Ge element elements, generally accurate to 0.1 mg, and the purity of the metal elements is above 99.99%. For volatile metals, appropriately increase the amount to compensate for the loss during the smelting process, such as Mn, for MnCoGe-based alloy samples, consider adding 3-10wt.% more;

[0026] S2. Carry out electric arc melting: put the prepared raw materials into a water-cooled copper crucible electric arc furnace, and pump the vacuum to 5×10 - 3 Below Pa, fill in argon gas with a purity of 99.999% at 1 atmosphere, and carry out arc melting. During the first smelting, melt the metal with a current of 28A. Just see the molten metal flowing in the crucible, and melt the first smelting Turn the block sample over, slightly increase the current ...

Embodiment 2

[0030] Alloys are designed according to principle, specifically Mn 0.965 co 1.035 Ge, the preparation steps are as follows:

[0031] S1. Dosing: According to the stoichiometric ratio, calculate the mass of the required Mn, Co, and Ge element elements, generally accurate to 0.1 mg, and the purity of the metal elements is above 99.99%. For volatile metals, appropriately increase the amount to compensate for the loss during the smelting process, such as Mn, for MnCoGe-based alloy samples, consider adding 3-10wt.% more;

[0032] S2. Carry out electric arc melting: put the prepared raw materials into a water-cooled copper crucible electric arc furnace, and pump the vacuum to 5×10 - 3 Below Pa, fill in argon gas with a purity of 99.999% at 1 atmosphere, and carry out arc melting. During the first smelting, melt the metal with a current of 28A. Just see the molten metal flowing in the crucible, and melt the first smelting Turn the block sample over, slightly increase the current ...

Embodiment 3

[0036] This embodiment designs the alloy according to the principle, Mn 1-x co 1+x In Ge, (x=0.015, x=0.02), namely Mn 0.985 co 1.015 Ge and Mn 0.98 co 1.02 Ge,

[0037] The difference between this embodiment and Embodiment 1 lies in that in step S3, the rotational speed of the high-energy ball milling process is 300 rpm, after the high-energy ball milling treatment, the ball milling time is 10 h. Other steps and selected parameters are the same as in Example 1. As a result, a sample with a large negative thermal expansion in a wide temperature range was obtained, and the Mn 0.985 co 1.015 Ge and Mn 0.98 co 1.02 Ge, a martensitic phase transformation with a wide temperature range was observed in the sample, and a huge negative thermal expansion in a wide temperature range was obtained.

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Abstract

The invention discloses a method for realizing giant negative thermal expansion of a wide temperature area in a MnCoGe base alloy, and belongs to the technical field of negative thermal expansion of MnCoGe base alloys. The method uses Co, Fe or Ni for replacing Mn to increase the valence electron concentration e / a; specific components Mn1-xCo1+xGe are designed, wherein c is not more than 0.15 andnot less than 0.01; the martensite phase change temperature of the alloy is lowered; the martensite phase change is coupled with the magnetic phase change to generate first-grade magnetic structure phase change at room temperature; and the method comprises the following steps: (S1) burdening is performed; (S2) arc smelting is performed to obtain Mn1-xCo1+xGe sample ingots; and (S3) aftertreatmentis performed on the Mn1-xCo1+xGe sample ingots obtained in the step (S2) to obtain Mn1-xCo1+xGe powder. The method is simple in preparation and low in cost; and obtained MnCoGe base alloy samples achieve negative thermal expansion of the wide temperature area near the room temperature.

Description

technical field [0001] The invention belongs to the preparation method of MnCoGe-based alloy material, especially relates to the special component Mn 1-x co 1+x The method of introducing defects and internal stress into Ge (0.01≤x≤0.15) to broaden the martensitic transformation temperature range of the alloy, thereby obtaining a large negative thermal expansion in a wide temperature range in the MnCoGe-based alloy. Background technique [0002] In the field of high-precision devices, such as fiber optic reflection grating devices, high-precision optical mirrors, and high-precision medical equipment, the thermal expansion of materials is a key factor for the thermal stability of equipment. But we know that most materials expand when heated and contract when cooled (that is, positive thermal expansion material, PTE), and it is difficult to find an ideal material with a desired thermal expansion coefficient. So negative thermal expansion (NTE) materials, which shrink when hea...

Claims

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Application Information

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IPC IPC(8): C22C1/02C22C30/00B22F9/04B22F9/14B82Y40/00
CPCB22F9/04B22F9/14B22F2009/043B82Y40/00C22C1/02C22C30/00
Inventor 马胜灿杨胜刘凯俞堃张智硕钟震晨
Owner JIANGXI UNIV OF SCI & TECH
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