Mn-Fe-Ni-Si-Cu based negative thermal expansion material and preparation method and application thereof

Abstract

The invention provides a Mn-Fe-Ni-Si-Cu-based negative thermal expansion material as well as a preparation method and application thereof, and belongs to the technical field of negative thermal expansion materials. The negative thermal expansion temperature range of the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material provided by the invention covers the high-temperature and low-temperature ranges (120K-896K), and the high-temperature and wide-temperature-range negative thermal expansion effect is shown; good mechanical properties are achieved; the material has extremely high thermal and mechanical stability, and has important significance for developing high-temperature precision mechanical devices based on zero expansion. The Mn-Fe-Ni-Si-Cu-based negative thermal expansion material disclosed by the invention is low in raw material cost and simple in preparation method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of negative thermal expansion materials, and particularly relates to a Mn-Fe-Ni-Si-Cu-based negative thermal expansion material and a preparation method and application thereof. BACKGROUND

[0002] Most materials have the characteristics of thermal expansion and contraction, that is, the volume of the material increases with the increase of temperature. The positive thermal expansion coefficient in general materials is relatively small, however, in precision instruments, even a length change of 10 -6 per degree Celsius can cause the failure of the device. Therefore, the development of materials with negative thermal expansion or zero expansion has important physical significance and application value, and among them, high-strength alloys with high-temperature low expansion coefficient are key materials in the fields of aerospace and energy.

[0003] The main way to realize negative thermal expansion and zero expansion is to use negative thermal expansion materials and positive expansion materials to control the thermal expansion coefficient of the material. Existing negative thermal expansion materials are mainly divided into two types: one is negative thermal expansion caused by lattice vibration, and the representative materials are β-spodumene, β-albite, ZrW2O8; the other is negative thermal expansion caused by phase transition, including magnetic phase transition materials such as Hf(Ta, Fe)2, La(Fe, Si) 13 Mn3AN; ferroelectric phase transition materials such as 0.4PbTiO3-0.6BiFeO3; and structural phase transition materials such as MM’X (M, M’ = transition group elements, X is main group elements such as Ge, Si). Negative thermal expansion materials based on phase transition are the main component of negative thermal expansion materials, however, the huge volume change during the phase transition of this kind of material will introduce internal stress, resulting in poor mechanical properties and difficulty in forming, thus unable to realize application.

[0004] MnNiSi-based alloys have a martensitic phase transition, and the volume abnormally increases by 4% during the cooling martensitic phase transition, and the phase transition temperature is as high as 1206K. By replacing part of Mn with Fe, the phase transition temperature of the alloy can be controlled to further control the temperature range of negative thermal expansion, so there is great potential in designing high-temperature negative expansion or low-expansion materials based on this kind of alloy. However, after the synthesis of this kind of alloy material, the alloy ingot will be broken into powder after cooling phase transition, and cannot be formed into an alloy block, and the MnNiSi material is all used with epoxy resin adhesive, which cannot realize further mechanical processing. Therefore, this kind of alloy is faced with the problems of difficulty in forming and poor mechanical properties. SUMMARY

[0005] The application aims to provide a Mn-Fe-Ni-Si-Cu-based negative thermal expansion material, a preparation method and application thereof.

[0006] In order to achieve the above-mentioned application purposes, the application provides the following technical solutions.

[0007] The application provides a Mn-Fe-Ni-Si-Cu-based negative thermal expansion material, which has a chemical composition of Mn 1-x Fe x NiSiCu y , wherein 0

[0008] Preferably, x = 0.2-0.8, and y = 0.1-1.2.

[0009] Preferably, x = 0.5, and y = 0.45.

[0010] The application provides a preparation method of the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material.

[0011] According to a required stoichiometric ratio, a Mn source, an Fe source, a Ni source, a Si source and a Cu source are mixed, and the obtained mixture is subjected to arc melting to obtain an alloy ingot.

[0012] The alloy ingot is subjected to annealing treatment to obtain the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material.

[0013] Preferably, the Mn source, the Fe source, the Ni source, the Si source and the Cu source are independently the corresponding single elements of each element.

[0014] Preferably, the temperature of the arc melting is 1500-2500 DEG C, the number of times of the arc melting is 3-5, and the background vacuum of the arc melting is < 3x10 -3 Pa.

[0015] Preferably, the temperature of the annealing treatment is 600-900 DEG C, the vacuum degree is < 1x10 -3 Pa, and the time is 1-10 days.

[0016] Preferably, the temperature range of the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material is 120K-896K.

[0017] The application provides application of the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material in precision instruments.

[0018] The application provides a Mn-Fe-Ni-Si-Cu-based negative thermal expansion material, wherein Fe is used to control the phase transition temperature range, so that the intrinsic 1200K phase transition is reduced to room temperature, and the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material is convenient to use; Cu is added to generate a Cu-rich nanophase between the main phase lattices, and the Cu-rich nanophase is completely coherent with the main phase, so that the mechanical properties are improved, and thus the alloy can remain in a bulk state after phase transition, and is convenient for subsequent mechanical processing, thereby solving the problems that the existing MnNiSi material cannot be formed and has poor mechanical properties.

[0019] The Mn-Fe-Ni-Si-Cu-based negative thermal expansion material is a composite material formed by a Mn-Fe-Ni-Si-Cu multi-component alloy, and the multi-component alloy has MnNiSi, MnNi 1.11 Si 0.89 , face-centered cubic Mn6Ni 16 Si7 phase and a Cu-rich nanophase distributed in the main phase MnNiSi. The hexagonal structure MnNiSi phase has a structural phase transition, and is transformed from a hexagonal structure into an orthogonal structure near the phase transition temperature, and the lattice volume changes by 4% during the process, and the phase is a functional phase for generating negative thermal expansion. The hexagonal structure MnNi 1.11 Si 0.89 is semi-coherent with the main phase MnNiSi; the Cu-rich phase is completely coherent with the main phase; and the second phase and the nanometer coherent second phase that are semi-coherent with the main phase help to improve the mechanical properties of the alloy. Therefore, the multi-component alloy can obtain a negative thermal expansion material with high compressive strength and ductility, a super-wide temperature range (high working temperature) and a tunable negative thermal expansion coefficient. The large number of interface dislocations induced in the interface of the Cu-rich nanophase, the MnNi 1.11 Si 0.89 phase and the face-centered cubic Mn6Ni 16 Si7 phase can partially solve the problem of difficulty in dislocation opening of the main phase of the alloy, and the nanotwin Cu-rich phase coherent with the main phase can induce dislocations and pass through, thereby effectively improving the compressive strength and ductility of the alloy, and changing the brittle fracture of the material into plastic fracture.

[0020] The Mn-Fe-Ni-Si-Cu-based negative thermal expansion material provided by the application has a negative thermal expansion temperature range covering a low temperature range (120K-523K) and a high temperature (755K-896K) range, exhibits a high temperature (the highest temperature range is up to 896K) and wide temperature range (the low temperature range covers a temperature of 403K, and the high temperature range covers a temperature of 141K) negative thermal expansion effect, has good mechanical properties, and has extremely high thermal and mechanical stability, which is of great significance for developing high-temperature precision mechanical devices based on zero expansion.

[0021] The application can adjust the negative thermal expansion coefficient by changing the alloy composition, and further can control the phase composition and distribution in the alloy by controlling the annealing time and temperature, so as to effectively control the mechanical properties of the alloy.

[0022] The Mn-Fe-Ni-Si-Cu-based negative thermal expansion material has low raw material cost and simple preparation method. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Mn 0.7 Fe 0.3 NiSiCu y Room temperature XRD patterns of Mn-Fe-Ni-Si-Cu-based negative thermal expansion materials with different y values (y=0.15, 0.3, 0.75);

[0024] Figure 2 Mn 0.6 Fe 0.4 NiSiCu y Room temperature XRD patterns of Mn-Fe-Ni-Si-Cu-based negative thermal expansion materials with different y values (y=0.15, 0.3, 0.75);

[0025] Figure 3 Mn 1-x Fe x NiSiCu y Backscattering scanning electron microscope images of Mn-Fe-Ni-Si-Cu-based negative thermal expansion materials with x=0.5 and y=0.45, wherein (a) is a backscattering image, (b) is a local enlarged view of (a), (c-g) are, in sequence, surface scanning images of Si, Ni, Cu, Fe, Mn components corresponding to the region of (b);

[0026] Figure 4 Mn 1-x Fe x NiSiCu y Transmission electron microscope images of Mn-Fe-Ni-Si-Cu-based negative thermal expansion materials with x=0.5 and y=0.45, wherein (a) is a bright field image of a coexisting region of a MnNiSi hexagonal main phase and a Mn6Ni 16 Si7 phase; (b) and (c) are, respectively, a MnNiSi main phase and a face-centered cubic Mn6Ni 16(d) is the electron diffraction pattern of Si7 phase, (e) is the corresponding Fourier transform pattern, (f) is the electron diffraction pattern of MnNiSi phase Mn6Ni 16 (d) is the electron diffraction pattern of Si7 phase, (e) is the corresponding Fourier transform pattern, (f) is the electron diffraction pattern of MnNiSi phase

[0027] Figure 5 Mn6Ni 1-x Fe x NiSiCu y The linear expansion amount of the material series (x = 0.3, y = 0.45; x = 0.4, y = 0.45; x = 0.4, y = 1.0; x = 0.5, y = 1.0) with temperature is shown in the schematic diagram.

[0028] Figure 6 Mn6Ni 1-x Fe x NiSiCu y The stress-strain curve at room temperature is shown in the diagram, wherein (a) is the Mn 0.7 Fe 0.3 NiSiCu y (y = 0.15, 0.45, 0.75), (b) is the Mn 0.6 Fe 0.4 NiSiCu y (y = 0.15, 0.45, 0.75). DETAILED DESCRIPTION

[0029] In the present application, the required raw materials or reagents are all commercially available goods well known to those skilled in the art, unless otherwise specified.

[0030] The present application provides a Mn-Fe-Ni-Si-Cu-based negative thermal expansion material, the chemical composition of which is Mn 1-x Fe x NiSiCu y , wherein 0 < x ≤ 1, 0 < y ≤ 1.5.

[0031] In the present application, preferably x = 0.2-0.8, more preferably 0.3-0.5, and further preferably x = 0.5.

[0032] In the present application, preferably y = 0.1-1.2, more preferably 0.15-1.0, further preferably y = 0.3-0.75, and further preferably y = 0.4-0.45.

[0033] The application provides a preparation method of the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material.

[0034] According to a required stoichiometric ratio, a Mn source, an Fe source, a Ni source, a Si source and a Cu source are mixed, and the obtained mixture is subjected to arc melting to obtain an alloy ingot.

[0035] The alloy ingot is subjected to annealing treatment to obtain the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material.

[0036] In the application, the Mn source, the Fe source, the Ni source, the Si source and the Cu source are independently preferably corresponding elements of each element; the purity of the Mn source, the Fe source, the Ni source, the Si source and the Cu source is all greater than or equal to 99.9wt%.

[0037] The application controls the phase ratio of the composite material by controlling the element ratio, and the negative thermal expansion coefficient of the composite material is continuously adjustable and the working temperature is adjustable.

[0038] The application preferably puts the raw materials prepared according to the stoichiometric ratio into an arc furnace, evacuates to a vacuum degree less than 3*10 -3 Pa, and then the furnace cavity is filled with the argon, and under the protection of 0.5-1 atmosphere, arc striking is performed, repeated melting is performed, and an alloy ingot is obtained.

[0039] In the application, the temperature of the arc melting is preferably 1500-2500 DEG C, and more preferably 2000 DEG C; the number of times of the arc melting is preferably 3-5 times, and more preferably 4 times; and the background vacuum of the arc melting is preferably less than 3*10 -3 Pa.

[0040] After the melting is completed, the alloy ingot is obtained by cooling in a copper crucible.

[0041] The application preferably seals the alloy ingot in a vacuum quartz tube after the alloy ingot is wrapped with a metal tantalum foil, and performs annealing treatment.

[0042] In the application, the temperature of the annealing treatment is preferably 600-900 DEG C, and more preferably 800-900 DEG C; the vacuum degree is preferably less than 1*10 -3 Pa, and more preferably 1*10 -4 Pa; and the time is preferably 1-10 days, and more preferably 2-5 days.

[0043] After the annealing treatment is completed, the application preferably cools the quartz tube with the furnace or quenches in an ice-water mixture, breaks the quartz tube, and obtains the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material.

[0044] In the present application, the temperature range of the Mn-Fe-Ni-Si-Cu based negative thermal expansion material is 120K-896K.

[0045] In the present application, the Mn-Fe-Ni-Si-Cu based negative thermal expansion material is an alloy with multiple intermetallic phases, mainly including MnNiSi alloy hexagonal structure (P63 / mmc), MnNi 1.11 Si 0.89 (P63 / mmc), Mn6Ni 16 Si7 face-centered cubic phase (Fm-3m), and Cu-rich nanophase distributed in the MnNiSi main phase. Among them, the MnNiSi alloy has a magnetic-structural phase transition, which changes from hexagonal phase to orthorhombic phase during the cooling process, and the volume change during the phase transition reaches 4%. The MnNi 1.11 Si 0.89 The face-centered cubic Mn6Ni 16 Si7 phase is coherent with the main phase, and the Cu-rich nanophase has a nanotwin structure. The interaction of these two intermetallic compounds with the MnNiSi main phase greatly improves the mechanical properties of the alloy, making the Mn 1- x Fe x NiSiCu y The material has both zero expansion effect and good mechanical properties.

[0046] The present application provides the application of the Mn-Fe-Ni-Si-Cu based negative thermal expansion material in precision instruments. The application method of the present application is not specially limited, and can be applied according to the methods well known in the art.

[0047] The specific embodiments of the present application are described in detail below, but it should be understood that the protection scope of the present application is not limited by the specific embodiments. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0048] The experimental methods in each embodiment of the present application are all conventional methods unless otherwise specified; the reagents and raw materials described below are commercially available unless otherwise specified.

[0049] Example 1

[0050] This embodiment is according to the chemical formula Mn 1-x Fe x NiSiCu yPreparation of composite materials, wherein x = 0.3, y = 0.15-1.0 (y = 0.15, 0.3, 0.45, 0.75, 1.0).

[0051] 1) The elemental Mn, Fe, Ni, Si, Cu raw materials with purity > 99.9wt% are prepared according to the chemical formula Mn 0.7 Fe 0.3 NiSiCu y The samples are weighed and mixed.

[0052] 2) The prepared raw materials in step 1) are placed in an electric arc furnace, vacuumed to <3x10 -3 Pa, and after purging the furnace cavity twice with high-purity argon (purity 99.996wt%), the arc is started under the protection of 0.5 atm of high-purity argon (purity 99.996wt%), and repeatedly melted 4 times, with the melting temperature being 2000℃. After the melting is completed, the alloy ingot is obtained by cooling in a copper crucible.

[0053] 3) The alloy ingot in step 2) is wrapped with a tantalum foil and sealed in a vacuum quartz tube (vacuum degree 1x10 - 4 Pa), and after annealing at 900℃ for 2 days, it is quenched in an ice-water mixture to obtain Mn 0.7 Fe 0.3 NiSiCu y series compound samples.

[0054] Example 2

[0055] This example is prepared according to the chemical formula Mn 1-x Fe x NiSiCu y Preparation of composite materials, wherein x = 0.4, y = 0.15-1.0 (y = 0.15, 0.3, 0.45, 0.75, 1.0).

[0056] 1) The elemental Mn, Fe, Ni, Si, Cu raw materials with purity > 99.9wt% are prepared according to the chemical formula Mn 0.6 Fe 0.4 NiSiCu y The samples are weighed and mixed.

[0057] 2) The prepared raw materials in step 1) are placed in an electric arc furnace, vacuumed to <3x10 -3 Pa, and after purging the furnace cavity twice with high-purity argon (purity 99.996wt%), the arc is started under the protection of 0.5 atm of high-purity argon (purity 99.996wt%), and repeatedly melted 4 times, with the melting temperature being 2000℃. After the melting is completed, the alloy ingot is obtained by cooling in a copper crucible.

[0058] 3) The alloy ingot prepared in step 2) is wrapped with a metal tantalum foil and sealed in a vacuum quartz tube (vacuum degree is 1 x 10 -4 Pa), annealed at 900°C for 2 days, and furnace-cooled to obtain a Mn 0.6 Fe 0.4 NiSiCu y series compound sample.

[0059] Example 3

[0060] In this example, a composite material is prepared according to the chemical formula Mn 1-x Fe x NiSiCu y wherein x = 0.5 and y = 0.15 to 1.0 (y = 0.15, 0.3, 0.45, 0.75, 1.0).

[0061] 1) The elemental Mn, Fe, Ni, Si, and Cu raw materials with purity > 99.9 wt% are prepared according to the chemical formula Mn 0.5 Fe 0.5 NiSiCu y The samples are weighed and mixed.

[0062] 2) The prepared raw materials in step 1) are placed in an arc furnace, vacuumed to < 3 x 10 -3 Pa, washed twice with high-purity argon (purity 99.996 wt%), and then arc-ignited under the protection of high-purity argon (purity 99.996 wt%) at 0.5 atm. The alloy ingot is obtained by repeatedly melting 4 times at a melting temperature of 2000°C, and then cooled in a copper crucible.

[0063] 3) The alloy ingot prepared in step 2) is wrapped with a metal tantalum foil and sealed in a vacuum quartz tube (vacuum degree is 1 x 10 -4 Pa), annealed at 900°C for 2 days, and furnace-cooled to obtain a Mn 0.5 Fe 0.5 NiSiCu y series compound sample.

[0064] Example 4

[0065] In this example, a composite material is prepared according to the chemical formula Mn 1-x Fe x NiSiCu y wherein x = 0.6 and y = 0.15 to 1.0 (y = 0.15, 0.3, 0.45, 0.75, 1.0).

[0066] 1) The elemental Mn, Fe, Ni, Si, and Cu raw materials with purity > 99.9 wt% are prepared according to the chemical formula Mn 0.4 Fe0.6 NiSiCu y Weigh the sample and mix it.

[0067] 2) Place the prepared raw materials from step 1) into the electric arc furnace and evacuate to a vacuum level of <3×10⁻⁶. -3 After being cleaned twice with high-purity argon gas (99.996 wt%), the alloy was ignited by electric arc under the protection of high-purity argon gas (99.996 wt%) at 0.5 atmospheres and repeatedly melted four times at a melting temperature of 2000℃. After melting, the alloy was cooled in a copper crucible to obtain a cast alloy ingot.

[0068] 3) Wrap the alloy ingot prepared in step 2) with tantalum foil and seal it in a vacuum quartz tube (vacuum degree 1×10⁻⁶). -4 After annealing at 900℃ for 2 days, Mn was obtained by furnace cooling. 0.4 Fe 0.6 NiSiCu y A series of compound samples.

[0069] Performance testing

[0070] (1)Mn 1-x Fe x NiSiCu y Structural and phase transition characterization

[0071] Representative Mn was measured using a Rigaku X-ray diffractometer from Japan. 1-x Fe x NiSiCu y (x=0.3, y=0.15, 0.3, 0.75); Mn 1-x Fe x NiSiCu y (x = 0.4, y = 0.15, 0.3, 0.75) The θ-2θ mode X-ray diffraction pattern at room temperature is as follows: Figure 1 and Figure 2 As shown. Analysis of the X-ray diffraction pattern reveals that the alloy mainly contains four phases: a MnNiSi-based hexagonal structure and an orthorhombic structure. Similarly, MnNi also exhibits a hexagonal structure. 1.11 Si 0.89 Phase and Mn6Ni with face-centered cubic structure 16 Si7.

[0072] (2)Mn 1-x Fe x NiSiCu y Phase composition and microstructure characterization

[0073] Image of Mn using a scanning electron microscope 1-x Fe xNiSiCu y (x = 0.5, y = 0.45) of the backscattered electron pattern Figure 3 (a), Figure 3 (b) is a local magnification of (a) where the MnNiSi main phase, hexagonal MnNi 1.11 Si 0.89 and face-centered cubic Mn6Ni 16 Si7 phase are marked. Figure 3 (c-g) are the corresponding surface scanning maps of Si, Ni, Cu, Fe, Mn components of the region of (b) in turn. From Figure 3 it can be seen that the MnNiSi main phase, hexagonal MnNi 1.11 Si 0.89 and face-centered cubic Mn6Ni 16 Si7 phase are interlaced and closely connected together in the material.

[0074] Figure 4 Mn 1-x Fe x NiSiCu y (x = 0.5, y = 0.45) alloy. (a) is a bright field image of the coexisting region of MnNiSi hexagonal main phase and Mn6Ni 16 Si7 phase, which can be seen that there are high-density nano precipitates in the MnNiSi alloy phase. Figure 4 (b) and (c) are electron diffraction patterns of the MnNiSi main phase and face-centered cubic Mn6Ni 16 Si7 phase respectively. Figure 4 (d) is a high-resolution map at the interface of the two phases, Figure 4 (e) is the corresponding Fourier transform map, combined with Figure 4 (b) and (d). Figure 4 (f) is the inverse Fourier transform map obtained by selecting the MnNiSi phase surface and Mn6Ni 16 Si7 phase (011) surface diffraction spot, which can be directly seen that the interface at the interface of the two phases has interface dislocation. Figure 4 (g) is a bright field phase of the MnNiSi main phase, Figure 4 (i) is a high-resolution map of the selected region of the bright field phase of the main phase, Figure 4 (h) is an electron diffraction pattern of the lattice region of the map, which can be seen that the shooting orientation is (0001) crystal phase. From Figure 5It can be seen that the Cu-rich nano-phase is coherent with the main phase and has a nano-twin structure. The introduction of a large number of interface dislocations at the multi-phase interface can partially solve the problem of difficult dislocation opening of the main phase of the alloy, and the nano-twin Cu-rich phase coherent with the main phase can induce dislocations and pass through, which can effectively improve the mechanical properties of the alloy and is one of the main factors to enhance the strength of the alloy.

[0075] (3)Mn 1-x Fe x NiSiCu y Measurement of the negative thermal expansion coefficient

[0076] The thermal expansion properties of the composite were measured using a thermal mechanical analyzer (TMA). Figure 6 Representative Mn 1- x Fe x NiSiCu y The thermal expansion-temperature curves of the alloys with compositions: x = 0.3, y = 0.45; x = 0.4, y = 0.45; x = 0.4, y = 1.0; x = 0.5, y = 1.0, where the abscissa is temperature and the ordinate is linear expansion, can be calculated to obtain the Mn 1-x Fe x NiSiCu y The linear thermal expansion coefficient of the material. At low Cu content (y = 0.45), Mn 1-x Fe x NiSiCu y (x = 0.3, x = 0.4) alloys exhibit negative thermal expansion effect in the low temperature region (120K-523K) and the high temperature region (755K-896K); with the increase of Cu content, x = 0.4, y = 1.0, the thermal expansion coefficient in the temperature range of 190K-580K is close to 0; x = 0.5, due to the addition of Fe to reduce the transition temperature of MnNiSi alloy, the alloy exhibits negative thermal expansion in the temperature range of 127K-323K.

[0077] (4)Mn 1-x Fe x NiSiCu y Mechanical property test of Mn

[0078] The stress-strain curves in compression mode were tested by using an electronic universal testing machine produced by Shimadzu Corporation of Japan, and the representative components: Mn 1-x Fe x NiSiCu y : x = 0.3, y = 0.15; x = 0.3, y = 0.45; x = 0.3, y = 0.75; x = 0.4, y = 0.15; x = 0.4, y = 0.45; x = 0.4, y = 0.75 were tested for compressive strength and strain, such as​ (a) is Mn 0.7 Fe 0.3 NiSi Cu y (y = 0.15, 0.45, 0.75), (b) is Mn 0.6 Fe 0.4 NiSiCu y (y = 0.15, 0.45, 0.75). In the component of x = 0.3, when the Cu content is y = 0.15, the Mn 1-x Fe x NiSiCu y alloy can be formed and the compressive strength is 201 MPa (Note: the component of y = 0.15 has already yielded at 1.5% strain, the compressive strength rising curve after 2% strain, the compressive strength performance of the sample itself); when the Cu content increases to 0.75, the Mn 1-x Fe x NiSiCu y alloy reaches 290 MPa. When x = 0.4, the Mn 1-x Fe x NiSiCu y compressive strength increases with the increase of Cu content, and reaches 519 MPa when y = 0.75. This is closely related to the second phase strengthening of the alloy.

[0079] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A Mn-Fe-Ni-Si-Cu based negative thermal expansion material, characterized in that, The chemical composition is Mn 1-x Fe x NiSiCu y , where 0 < x ≤ 1, 0 < y ≤ 1.

5.

2. The Mn-Fe-Ni-Si-Cu-based negative thermal expansion material according to claim 1, characterized in that, x=0.2~0.8, y=0.1~1.

2.

3. The Mn-Fe-Ni-Si-Cu-based negative thermal expansion material according to claim 1, characterized in that, x = 0.5, y = 0.

45.

4. The method for preparing the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material according to any one of claims 1 to 3, characterized in that, Includes the following steps: According to the required stoichiometric ratio, Mn source, Fe source, Ni source, Si source and Cu source are mixed, and the resulting mixture is subjected to electric arc melting to obtain alloy ingot; The alloy ingot was annealed to obtain a Mn-Fe-Ni-Si-Cu based negative thermal expansion material.

5. The preparation method according to claim 4, characterized in that, The Mn source, Fe source, Ni source, Si source, and Cu source are each an elemental substance.

6. The preparation method according to claim 4, characterized in that, The temperature of the electric arc melting is 1500–2500℃; the number of electric arc melting cycles is 3–5; and the background vacuum of the electric arc melting is <3×10⁻⁶. -3 Pa.

7. The preparation method according to claim 4, characterized in that, The annealing treatment is performed at a temperature of 600–900°C, with a vacuum degree of <1×10⁻⁶. -3 Pa, the time is 1 to 10 days.

8. The preparation method according to claim 4, characterized in that, The temperature range of the Mn-Fe-Ni-Si-Cu-based negative thermal expansion material is 120K to 896K.

9. The application of the Mn-Fe-Ni-Si-Cu based negative thermal expansion material according to any one of claims 1 to 3 or the Mn-Fe-Ni-Si-Cu based negative thermal expansion material prepared by the preparation method according to any one of claims 4 to 8 in precision instruments.

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