阅读说明：本技术 一种具有原位析出共格沉淀相的磁性记忆合金及其制备方法 (Magnetic memory alloy with in-situ precipitated coherent precipitated phase and preparation method thereof ) 是由 巨佳 刘壮 康彦 张思斌 巴志新 毛向阳 张保森 许永祥 张慧 于 2018-08-10 设计创作，主要内容包括：本发明提供一种具有原位析出共格沉淀相的磁性记忆合金及其制备方法,属于形状记忆合金领域,该合金与现有材料相比具备优良的兼具优良力学性能和优良的磁性性能这两方面的优点。该合金化学式为：Co<Sub>x</Sub>Ni<Sub>y</Sub>Al<Sub>z</Sub>Tm<Sub>j</Sub>；其中,35.1≤x≤39.9,29.6≤y≤32.7,28.5≤z≤31.8,0.9≤j≤1.8,x+y+z+j＝100,x、y、z、j表示摩尔百分比含量。本发明磁控形状记忆合金与现有材料相比,在合金的基体相中形成的微米级别短棒状的共格Co<Sub>5</Sub>Tm金属中间相,使合金兼具良好的力学性能和磁性性能的特征,促使合金能够实现兼具优良力学性能和磁性性能的特点,大大的拓宽了该类合金的工业应用范围。(The invention provides a magnetic memory alloy with in-situ precipitated coherent precipitated phase and a preparation method thereof, belonging to the field of shape memory alloys. The alloy has the chemical formula as follows: co x Ni y Al z Tm j (ii) a Wherein x is more than or equal to 35.1 and less than or equal to 39.9, y is more than or equal to 29.6 and less than or equal to 32.7, z is more than or equal to 28.5 and less than or equal to 31.8, j is more than or equal to 0.9 and less than or equal to 1.8, and x + y + z + j is equal to100, and x, y, z and j represent the content of mole percent. Compared with the prior material, the magnetic control shape memory alloy of the invention forms micron-level short rod-shaped coherent Co in the matrix phase of the alloy 5 The Tm metal intermediate phase ensures that the alloy has the characteristics of good mechanical property and magnetic property, promotes the alloy to have the characteristics of good mechanical property and magnetic property, and greatly widens the industrial application range of the alloy.)

1. A magnetic memory alloy having in-situ precipitation of coherent precipitate phases, characterized by: the raw materials and the mixture ratio are as follows by mol percent:

the preparation process of the magnetic memory alloy with the in-situ precipitated coherent precipitated phase is characterized by comprising the following specific steps of:

s1, material preparation: proportioning and weighing according to the proportion;

s2, smelting: putting the prepared raw materials into a crucible for vacuum melting, wherein the melting conditions are as follows: a.1X 10^-3～5×10^{- 3}A low vacuum state of MPa; b. the smelting temperature is 1450-1550 ℃; c. magnetic stirring is adopted in the smelting process; d. melting time is according to the formula t ═ K × (M)^-1/2) Obtained by the reaction of the following formula, wherein the element coefficient K is 15 to 20 s.g^-1/2M is the mass of the alloy being smelted and is given in g; t is melting time in units of s;

s3, magnetic field heat treatment: carrying out vacuum magnetic field heat treatment on the alloy ingot obtained by vacuum melting under the following treatment conditions: the temperature is 600-650 ℃; time: 10-15 hours; vacuum degree: 1X 10^-3～5×10^-3MPa; applying magnetic field intensity: 2X 10⁶～2×10⁷A·m^-1(ii) a The magnetic field rise rate is: 1200 A.m^-1·s^-1；

S4, cooling; and then cooling along with the furnace, wherein the cooling speed range is as follows: 0.01 to 0.5 ℃ s^-1(ii) a The magnetic field reduction rate was: 1200 A.m^-1·s^-1(ii) a And cooling to room temperature and taking out to obtain the final magnetic memory alloy.

2. A magnetic memory alloy having in-situ precipitated coherent precipitate phases, the memory alloy having the formula: co_xNi_yAl_zTm_j(ii) a Wherein x is more than or equal to 35.1 and less than or equal to 39.9, y is more than or equal to 29.6 and less than or equal to 32.7, z is more than or equal to 28.5 and less than or equal to 31.8, j is more than or equal to 0.9 and less than or equal to 1.8, x + y + z + j is 100, and x, y, z and j represent the content in mole percentage.

3. A magnetic memory alloy with in-situ precipitated coherent precipitated phase is characterized in that micron-level short rod-shaped coherent Co is formed in a matrix phase of the memory alloy₅Tm metal mesophase.

4. The magnetic memory alloy with in-situ precipitation coherent precipitated phases as claimed in claim 2, wherein said memory alloy is prepared by the method of claim 1.

Technical Field

The invention belongs to the field of shape memory alloys, and particularly relates to a magnetic memory alloy with in-situ precipitated coherent precipitated phase and a preparation method thereof

Background

Magnetic shape memory alloys are a new class of shape memory alloys that developed in the last 90 th century. The shape memory alloy has the characteristics of thermoelastic martensite phase transformation and ferromagnetic transformation at the same time, and can realize the control of the deformation of the shape memory alloy by a magnetic field. Conventional temperature-controlled shape memory alloys, such as NiTi-based and Fe-based alloys, have large strain but slow response, while shape memory alloys, such as giant magnetostrictive materials and piezoelectric materials, have high response frequency and small strain. The magnetic shape memory alloy is a new shape memory alloy, and has the characteristics of large strain and quick response, and the alloy also has the accompanied physical effects of magnetocaloric property, magnetic resistance and the like. Therefore, the magnetic shape memory alloy is considered to be the leading of a novel functional material, and can be widely applied to the fields of biology, environment, aviation and the like.

At present, Adaptamat of Finland has already introduced Ni₂The MnGa alloy is used as a driving sensitive material to be applied to the manufacture of a novel driver. However, the function failure of the driver can occur after the driver is used for a plurality of times in a circulating way, and the reason is caused by the magneto-strain functional fatigue of the magnetic shape memory alloy, so that the on-line work of the driver is seriously hinderedApplication and popularization in the industrial field. Therefore, it is desired to develop a new magnetic control shape memory alloy with excellent mechanical properties, large magnetic strain and long functional fatigue life to accelerate the industrial application and popularization.

Disclosure of Invention

In order to overcome the defects, the invention provides a magnetic memory alloy with in-situ precipitated coherent phases and a preparation method of the magnetic memory alloy with in-situ precipitated coherent phases.

In order to achieve the purpose of the invention, the technical scheme of the invention is as follows: a magnetic memory alloy having in-situ precipitation of coherent precipitate phases, characterized by: the raw materials and the mixture ratio are as follows by mol percent:

the invention also discloses a preparation process of the magnetic memory alloy with the in-situ precipitated coherent precipitated phase, which is characterized by comprising the following specific steps of:

s1, material preparation: proportioning and weighing according to the proportion;

s2, smelting: putting the prepared raw materials into a crucible for vacuum melting, wherein the melting conditions are as follows: a.1X 10^-3～5×10^-3A low vacuum state of MPa; b. the smelting temperature is 1450-1550 ℃; c. magnetic stirring is adopted in the smelting process; d. melting time is according to the formula t ═ K × (M)^-1/2) Obtained by the reaction of the following formula, wherein the element coefficient K is 15 to 20 s.g^-1/2M is the mass of the alloy being smelted and is given in g; t is melting time in units of s;

s3, magnetic field heat treatment: carrying out vacuum magnetic field heat treatment on the alloy ingot obtained by vacuum melting under the following treatment conditions: the temperature is 600-650 ℃; time: 10-15 hours; vacuum degree: 1X 10^-3～5×10^-3MPa; applying magnetic field intensity: 2X 10⁶～2×10⁷A·m^-1(ii) a The magnetic field rise rate is: 1200 A.m^-1·s^-1；

S4, cooling; then cooling along with the furnaceThe speed ranges are: 0.01 to 0.5 ℃ s^-1(ii) a The magnetic field reduction rate was: 1200 A.m^-1·s^-1(ii) a And cooling to room temperature and taking out to obtain the final magnetic memory alloy.

Further, the magnetic memory alloy with the in-situ precipitated coherent precipitated phase is characterized by having the chemical formula: co_xNi_yAl_zTm_j(ii) a Wherein x is more than or equal to 35.1 and less than or equal to 39.9, y is more than or equal to 29.6 and less than or equal to 32.7, z is more than or equal to 28.5 and less than or equal to 31.8, j is more than or equal to 0.9 and less than or equal to 1.8, x + y + z + j is 100, and x, y, z and j represent the content in mole percentage.

Further, the magnetic memory alloy with the in-situ precipitated coherent precipitated phase is characterized in that the coherent Co with micron-scale short rod shape is formed in the matrix phase of the memory alloy₅Tm metal mesophase.

The magnetic memory alloy with the in-situ precipitated coherent precipitated phase has the capability of generating deformation under the control of an external magnetic field in a room temperature range, and has the advantages of large magnetic strain and long functional life. Micron-level short rod-shaped coherent Co formed in matrix phase of magnetic memory alloy₅The Tm metal intermediate phase ensures that the alloy has the characteristics of good mechanical property and magnetic property, and promotes the alloy to have the characteristics of good mechanical property and magnetic property.

Compared with the prior art, the invention has the following advantages:

the invention provides a magnetic memory alloy with in-situ precipitated coherent precipitated phase, and compared with other magnetic shape memory alloys, the magnetic memory alloy forms micron-level short rod-shaped coherent Co in a matrix phase of the alloy₅The Tm metal intermediate phase ensures that the alloy has the characteristics of good mechanical property and magnetic property, promotes the alloy to have the characteristics of good mechanical property and magnetic property, and greatly widens the industrial application range of the alloy.

Compared with the existing material, the magnetic memory alloy with the in-situ precipitated coherent precipitated phase has the advantages of excellent mechanical property and excellent magnetic property.

(1): excellent mechanical properties: the matrix phase in the Co-Ni system belongs to a brittle phase, and the comprehensive mechanical property of the matrix phase is poor, so that the alloy cannot be precisely processed and used. The Tm element in the Co-Ni system has limited solid solubility, supersaturated Tm atoms are separated out and react with Co in a matrix phase under the process condition of the invention to form micron-level short-rod-shaped coherent Co with excellent comprehensive mechanical property₅The Tm metal intermediate phase is greatly superior to the matrix phase in strength and toughness and plasticity of the intermetallic compound, and a large amount of metal intermediate phase is distributed in the alloy matrix phase, so that the overall mechanical property of the alloy can be obviously enhanced.

(2): higher saturation magnetization: co₅The Tm metal intermediate phase has stronger magnetic property and belongs to a strong magnetic phase. In the invention patent, a great amount of micron-scale short rod-shaped coherent Co is formed in an alloy matrix phase under specific process conditions₅The Tm metal intermediate phase can greatly improve the magnetic property of the alloy, and particularly the saturation magnetization of the alloy is obviously improved.

(3): higher magnetocrystalline anisotropy: co formed under specific process conditions in the patent of the invention₅The Tm metal mesophase is a short rod whose magnetic properties have significant anisotropy in various directions. At the same time, Co formed in the matrix phase₅The obvious preferred orientation growth trend in the middle of the Tm metal causes the magnetocrystalline anisotropy of the alloy on the whole to be increased, and the magnetocrystalline anisotropy of the alloy is improved.

(4): the preparation method comprises the following steps: the invention adopts the vacuum crucible for smelting, and in the smelting process, because the system is in a vacuum state, the mechanical and magnetic properties of the alloy are prevented from being reduced due to surface oxidation. Compared with the traditional method, the method also has the effect of gathering the internal smelting defects of the alloy to the surface so as to enhance the processing performance of the material, such as holes and the like. The perfect matching of the melting temperature and the melting time not only ensures that pure metal has enough time and temperature to be melted into alloy ingots, but also can avoid the burning loss of alloy components caused by overhigh temperature and overlong time. Co in alloy structure₅The Tm metal mesophase belongs to an unstable metal mesophase, which is in a solidification stageThere is a tendency to decompose and not be retained in the alloy structure by conventional means. However, the invention adopts a magnetic field vacuum heat treatment mode, and induces the magnetic domains in the alloy to present obvious preferential distribution in an external magnetic field mode, particularly the matrix phase structure of Co and Tm aggregation, and the magnetic domains are directionally arranged under the drive of the external magnetic field, thereby changing the Co₅The magnetic entropy of the intermediate phase of the Tm metal is improved, and Co is improved₅Stability of Tm metal intermediate phase, Co distributed in coherent ultra-fine dispersion₅The Tm metal mesophase is capable of being stably present in the matrix phase of the alloys of the present invention. In addition, the magnetic domain after orientation distribution further strengthens the magnetocrystalline anisotropy of the alloy.

In conclusion, the invention provides the magnetic memory alloy with the in-situ precipitated coherent precipitated phase and the preparation method thereof, and the alloy has the advantages of excellent mechanical property and excellent magnetic property compared with other magnetic control shape memory alloys.

Drawings

FIG. 1 shows Co of the present invention_xNi_yAl_zTm_jSEM images of the alloys at room temperature;

Detailed Description

The invention is further illustrated by the following examples.