A high-damping Ni-Co-Mn-Sn magnetic shape memory alloy and a preparation method thereof

Abstract

The application discloses a high-damping Ni-Co-Mn-Sn magnetic shape memory alloy and a preparation method thereof. 45 Co5Mn 43‑x Sn 7+x , wherein x=0-3, and the preparation method comprises the following steps: taking nickel, cobalt, manganese and tin according to the stoichiometric ratio of Ni 45 Co5Mn 43‑x Sn 7+x , respectively, mixing and vacuum smelting, continuing smelting after inert gas is filled, and finally casting to obtain the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy. The high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared by the method has the advantages of simple preparation method, low raw material price, saved alloy preparation cost, adjustable phase transition temperature of the alloy through the change of the Mn and Sn content, good controllability, high phase transition temperature of the prepared alloy, promoted formation of more martensite structure, and good damping performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alloys, in particular to a high-damping Ni-Co-Mn-Sn magnetic shape memory alloy and a preparation method thereof. BACKGROUND

[0002] With the development of technology, intelligent materials play a crucial role in replacing traditional materials. Shape memory alloys, as a kind of intelligent material, can recover shape under the conditions of heat, magnetic change and low temperature. There are various types of shape memory alloys, such as temperature-controlled shape memory alloys, magnetic shape memory alloys, shape memory thin films, etc. Magnetic shape memory alloys are a new type of shape memory alloy developed in recent years. This type of alloy has both thermal-elastic martensitic phase transition and ferromagnetic transition, so its deformation can be controlled by a magnetic field. Compared with traditional temperature-controlled shape memory alloys and giant magnetostrictive materials, magnetic shape memory alloys have the comprehensive advantages of large strain and fast response. Magnetic shape memory alloys mainly include Ni-Mn-(Sn, In, Ga) base alloys. Among them, Ga and In elements are both noble metals, which have high cost and are toxic.

[0003] With the development of modern industry, there are different degrees of noise and vibration in the fields of aviation, aerospace and rail transportation. In order to reduce the harm caused by vibration and noise, the commonly used method is to use materials with high damping performance in key components, and damping alloys are an important branch of many damping materials. Metals can be divided into two categories according to the size of damping capacity: one category is aluminum alloy, copper alloy, titanium alloy and steel, etc., which have low damping performance; the other category is Fe, Ni, Mn-Cu alloy, which has high damping performance. The damping alloys developed at present can be divided into four types according to different damping mechanisms, which are complex phase type, ferromagnetic type, dislocation type and twinning type. Among them, the twinning type and the ferromagnetic type of damping alloys are affected by high temperature and magnetic field respectively, which seriously affects the practical application of the alloy, so it is necessary to study a high-damping alloy that can resist high temperature and magnetic field.

[0004] Ni-Mn-Sn-based magnetic shape memory alloy, the high-temperature austenite phase is L21 structure. According to different conditions, four typical structures including 4O type modulation, 10M type modulation, 14M type modulation based on L10 type non-modulation. The phase transition of Ni-Mn-Sn alloy can be divided into several steps, which can be divided into: liquid-solid phase transition, order-disorder phase transition, paramagnetic-ferromagnetic transition, martensitic phase transition. According to the phase diagram, the Ni-Mn-Sn alloy in liquid state first forms the disordered B2 type solid phase with CsCl structure during the cooling process. When the temperature decreases, the disordered B2 type solid phase is converted into the ordered L21 type solid phase, and this process is the order-disorder transition stage. The Ni-Mn-Sn alloy parent phase will undergo martensitic phase transition at a certain cooling rate during the cooling process of the L21 type solid phase. The martensitic phase will change from unstable structure to stable structure through multiple transitions as the temperature decreases.

[0005] Through the phase transition process of Ni-Mn-Sn-based alloy, it can be determined that the alloy exists in the martensitic structure at room temperature. According to the Mn-Cu alloy with high damping performance and the Cu-Al-based shape memory alloy with temperature control, both alloy matrices exist in the martensitic structure and the twinning substructure, thereby having good twinning damping performance. Generally, the martensitic phase transition temperature of Ni-Mn-based magnetic shape memory alloy is generally near room temperature, which causes the martensitic phase transition to be below room temperature, so that it does not have damping performance near room temperature. SUMMARY

[0006] In order to solve the above technical problems, the purpose of the present application is to provide a high-damping Ni-Co-Mn-Sn magnetic shape memory alloy and a preparation method thereof, so as to solve the problems of low phase transition temperature and damping performance of existing memory alloys, and the problem that high-temperature resistance and magnetic field resistance cannot be compatible.

[0007] The technical scheme for solving the above technical problems of the present application is as follows:

[0008] A high-damping Ni-Co-Mn-Sn magnetic shape memory alloy, the chemical formula is Ni 45 Co5Mn 43-x Sn 7+x , wherein x=0-3.

[0009] Further, a high-damping Ni-Co-Mn-Sn magnetic shape memory alloy, the chemical formula is Ni 45 Co5Mn 42 Sn7, Ni 45 Co5Mn 41 Sn8 or Ni 45 Co5Mn 40 Sn 10 .

[0010] The preparation method of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy has the characteristics that it comprises the following steps:

[0011] According to the stoichiometric ratio of Ni 45 Co5Mn 43-x Sn 7+x , respectively, the nickel, cobalt, manganese and tin are mixed and vacuum smelted, then the inert gas is filled and the smelting is continued, and finally the casting is made.

[0012] Further, the purity of the nickel block, cobalt sheet, manganese sheet and tin block is greater than 99.9%.

[0013] Further, the vacuum degree of the vacuum smelting is less than 4.5*10 -3 Pa.

[0014] Further, the temperature of the vacuum smelting and the continued smelting is 1500-1700℃.

[0015] Further, the time of the vacuum smelting and the continued smelting is 30-50min.

[0016] Further, the pressure of the inert gas after being filled is 0.05-0.07MPa.

[0017] The high-damping Ni-Co-Mn-Sn magnetic shape memory alloy is applied in shock absorption and noise reduction.

[0018] The present application has the following beneficial effects:

[0019] (1) The preparation method of the Ni-Co-Mn-Sn magnetic shape memory alloy is simple, and the raw material price is low; unlike the general vacuum arc smelting, the present application adopts vacuum induction smelting, which can reduce the volatilization of Mn element in the smelting process and maintain good uniformity; and the alloy after smelting can be used without subsequent heat treatment, which greatly saves the preparation cost of the alloy.

[0020] (2) The Ni-Co-Mn-Sn magnetic shape memory alloy can adjust the phase transition temperature of the alloy by changing the content of Mn and Sn, and has good controllability. And the phase transition temperature of the prepared alloy is high, which can promote the formation of more martensite structure, thereby having good damping performance. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 DSC test results of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared in Example 1;

[0022] Figure 2DSC test results of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared for Example 1;

[0023] Figure 3 DSC test results of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared for Example 3;

[0024] Figure 4 DSC test results of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared for Comparative Example 1;

[0025] Figure 5 A graph of internal friction varying with strain amplitude of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared for Example 1;

[0026] Figure 6 A graph of dynamic mechanical loss varying with temperature of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared for Example 1;

[0027] Figure 7 A graph of internal friction varying with strain amplitude of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared for Example 2;

[0028] Figure 8 A graph of internal friction varying with strain amplitude of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared for Example 3;

[0029] Figure 9 A graph of internal friction varying with strain amplitude of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared for Comparative Example 1. DETAILED DESCRIPTION

[0030] The principles and features of the present application are described below in conjunction with the accompanying drawings, in which the examples are used to explain the present application and are not intended to limit the scope of the present application. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments not mentioned by the manufacturer are all conventional products that can be purchased on the market.

[0031] Example 1:

[0032] A high-damping Ni-Co-Mn-Sn magnetic shape memory alloy comprising the following atomic percentage components: Ni 45%, Co 5%, Mn 43%, and Sn 7%.

[0033] A preparation method thereof, comprising the following steps:

[0034] (1) batching: according to the atomic percentage components of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy, the raw materials are weighed and mixed to prepare a mixed powder; 45 Co 5 Mn 43Sn7 atomic percentage of pure nickel, purity of 99.99 % cobalt, purity of 99.99 % manganese and purity of 99.99 % tin.

[0035] (2) drying: the surface of the nickel, cobalt, manganese and tin weighed in step (1) is polished and cleaned, and is placed in a drying oven at 300 DEG C for 24 h to ensure that the raw materials are free of moisture.

[0036] (3) loading: the dried raw materials are loaded into a crucible in a vacuum induction furnace, the ingot mold is placed in the furnace, the furnace door is closed, and the gas valve is tightened.

[0037] (4) vacuumizing: the high vacuum valve is closed, the low vacuum valve is opened, the mechanical pump is started, then the pre-vacuum valve is opened, and the diffusion pump power is turned on. When the vacuum degree reaches 500 Pa, the Roots pump is opened until the vacuum degree reaches 2-3 Pa. After the diffusion pump is heated for 30 min, when the vacuum degree reaches below 2 Pa, the low vacuum valve is closed, the high vacuum valve is opened, and the high vacuum state is entered, and the vacuum degree is maintained below 4.5 x 10 -3 Pa.

[0038] (5) vacuum melting: the power of the vacuum induction furnace is adjusted to 28 kW, the temperature is raised to 1600 DEG C, and the raw materials are treated for 50 min to obtain a liquid mixture.

[0039] (6) argon filling: the power of the vacuum induction furnace is adjusted to 0, and the inside of the furnace cavity is filled with argon with a purity of 99.9 %, and the filling is stopped when the pressure reaches 0.06 MPa.

[0040] (7) continue melting: the power of the vacuum induction furnace is adjusted to 20 kW, and the liquid is kept for 50 min.

[0041] (8) casting: the high vacuum valve is closed, the Roots pump is closed, and the refined liquid mixture is slowly cast into the ingot mold, and then is left to stand for 30 min to obtain a.

[0042] Example 2:

[0043] A high-damping Ni-Co-Mn-Sn magnetic shape memory alloy, comprising the following atomic percentage components: Ni45 %, Co5 %, Mn42 %, Sn8 %.

[0044] A preparation method thereof, comprising the following steps:

[0045] (1) batching: according to the atomic percentage of Ni 45 Co5Mn 42 Sn8, pure nickel with a purity of 99.99 %, pure cobalt with a purity of 99.99 %, pure manganese with a purity of 99.99 %, and pure tin with a purity of 99.99 % are weighed.

[0046] (2) Drying: the nickel, cobalt, manganese and tin surface weighed in step (1) is polished and cleaned, and is placed in a drying oven at 300°C for 24h to ensure that the raw materials are free of moisture.

[0047] (3) Charging: the dried raw materials are charged into a crucible in a vacuum induction furnace, the ingot mold is placed in the furnace, the furnace door is closed, and the gas valve is tightened.

[0048] (4) Vacuum pumping: the high vacuum valve is closed, the low vacuum valve is opened, the mechanical pump is started, then the pre-vacuum valve is opened, and the diffusion pump power is turned on. When the vacuum degree reaches 500Pa, the Roots pump is opened until the vacuum degree reaches 2-3Pa. After the diffusion pump is heated for 30min, when the vacuum degree reaches below 2Pa, the low vacuum valve is closed, the high vacuum valve is opened, and the high vacuum pumping state is entered, and the vacuum degree is maintained below 4.5x10 -3 Pa.

[0049] (5) Vacuum melting: the power of the vacuum induction furnace is adjusted to 28kW, the temperature is raised to 1600°C, and the raw materials are treated for 50min to obtain a liquid mixture.

[0050] (6) Argon filling: the power of the vacuum induction furnace is adjusted to 0, and the inside of the furnace cavity is filled with argon with a purity of 99.9%, and when the pressure reaches 0.06Mpa, the process is stopped.

[0051] (7) Continue melting: the power of the vacuum induction furnace is adjusted to 20kW, and the liquid is kept for 50min to fully fuse.

[0052] (8) Casting: the high vacuum valve is closed, the Roots pump is closed, and the refined liquid mixture is slowly cast into the ingot mold, and then it is left to stand for 30min to obtain a.

[0053] Example 3:

[0054] A high-damping Ni-Co-Mn-Sn magnetic shape memory alloy includes the following atomic percentage components: Ni45%, Co5%, Mn40%, and Sn10%.

[0055] A preparation method thereof includes the following steps:

[0056] (1) batching: according to the atomic percentage of Ni 45 Co5Mn 42 Sn8, pure nickel with a purity of 99.99%, pure cobalt with a purity of 99.99%, pure manganese with a purity of 99.99%, and pure tin with a purity of 99.99% are weighed.

[0057] (2) Drying: the surface of the weighed nickel, cobalt, manganese and tin in step (1) is polished and cleaned, and then placed in a drying oven and dried at 300°C for 24h to ensure that the raw materials are free of moisture.

[0058] (3) Charging: the dried raw materials are charged into a crucible in a vacuum induction furnace, the ingot mold is placed in the furnace, the furnace door is closed, and the gas valve is tightened.

[0059] (4) Vacuum pumping: close the high vacuum valve, open the low vacuum valve, start the mechanical pump, then open the pre-vacuum valve, and turn on the diffusion pump power. When the vacuum degree reaches 500Pa, open the Roots pump until the vacuum degree reaches 2-3Pa. After the diffusion pump is heated for 30min, when the vacuum degree reaches below 2Pa, close the low vacuum valve and open the high vacuum valve to enter the high vacuum pumping state, and maintain the vacuum degree less than 4.5x10 -3 Pa.

[0060] (5) Vacuum melting: adjust the power of the vacuum induction furnace to 28kW, and raise the temperature to 1600°C for 50min until the raw materials are melted to obtain a liquid mixture.

[0061] (6) Argon filling: adjust the power of the vacuum induction furnace to 0, and fill the inside of the furnace cavity with argon with a purity of 99.9%, and stop when the pressure reaches 0.06Mpa.

[0062] (7) Continue melting: continue to adjust the power of the vacuum induction furnace to 20kW and maintain for 50min until the liquid is fully fused.

[0063] (8) Casting: close the high vacuum valve and the Roots pump, and slowly cast the refined liquid mixture into the ingot mold, then stand for 30min to obtain.

[0064] Comparative Example 1

[0065] A high-damping Ni-Co-Mn-Sn magnetic shape memory alloy, comprising the following atomic percentage components: Ni 45%, Co 5%, Mn 42%, Sn 8%.

[0066] A preparation method thereof, comprising the following steps:

[0067] (1) batching: according to the atomic percentage of Ni 45 Co5Mn 42 Sn8, weigh nickel with a purity of 99.99%, cobalt with a purity of 99.99%, manganese with a purity of 99.99%, and tin with a purity of 99.99%.

[0068] (2) Drying: the surface of the weighed nickel, cobalt, manganese and tin in step (1) is polished and cleaned, and then placed in a drying oven and dried at 300°C for 24h to ensure that the raw materials are free of moisture.

[0069] (3) Charging: After drying the raw materials, they are charged into the crucible in the vacuum induction furnace, the pouring ingot mold is put into the furnace, the furnace door is closed, and the gas valve is tightened.

[0070] (4) Vacuum pumping: Close the high vacuum valve, open the low vacuum valve, start the mechanical pump, then open the pre-vacuum valve, and turn on the diffusion pump power. When the vacuum degree reaches 500 Pa, open the Roots pump until the vacuum degree reaches 2-3 Pa. After the diffusion pump is heated for 30 min, when the vacuum degree reaches below 2 Pa, close the low vacuum valve, open the high vacuum valve, enter the high vacuum pumping state, and keep the vacuum degree less than 4.5 x 10 -3 Pa.

[0071] (5) Vacuum melting: The power of the vacuum hole induction furnace is modulated to 28 kW, the temperature is raised to 1600℃, and the treatment is performed for 50 min, until the raw materials are melted to obtain a liquid mixture.

[0072] (6) Argon filling: The power of the vacuum induction furnace is adjusted to 0, and the inside of the furnace cavity is filled with argon with a purity of 99.9%, and when the pressure reaches 0.06 MPa, it is stopped.

[0073] (7) Continue melting: Continue to adjust the power of the vacuum induction furnace to 20 kW and keep it for 50 min until the liquid is fully fused.

[0074] (8) Casting: Close the high vacuum valve, close the Roots pump, and slowly cast the refined liquid mixture into the ingot mold, then stand for 30 min.

[0075] (9) Heat treatment: The cast ingot is placed in a muffle furnace for heat treatment, the heating temperature is 900℃, and the holding time is 12 h, then it is taken out and water cooled to obtain.

[0076] Test Example 1:

[0077] The high-damping Ni-Co-Mn-Sn magnetic shape memory alloy prepared in Example 1-3 and Comparative Example 1 is subjected to experiments.

[0078] Using wire cutting technology, the sample is cut into a block-shaped sample of 2 x 2 x 2 mm, and the block-shaped sample is polished to remove impurities on the surface, and then tested for phase transition temperature point by DSC, and the experimental results are shown in Figures 1-4 .

[0079] From Figure 1 it can be seen that the Ni 45 Co5Mn 43The starting temperature (Ms), ending temperature (Mf), starting temperature (As), and ending temperature (Af) of the martensitic transformation in Sn7 alloy are 317℃, 260℃, 275℃, and 333℃, respectively, making it a high-temperature alloy. Figure 2 As can be seen from the example, the Ni prepared in Example 2 45 Co5Mn 42 The Ms, Mf, As, and Af points of the Sn8 alloy are 307℃, 217℃, 253℃, and 316℃, respectively. This is in contrast to the Ni alloy prepared in Example 1. 45 Co5Mn 43 The phase transition temperatures of Sn7 all decreased; from Figure 3 As can be seen from the example, the Ni prepared in Example 3 45 Co5Mn 40 Sn 10 The Ms, Mf, As, and Af values ​​of the alloy are 280℃, 81℃, 114℃, and 287℃, respectively, with significant decreases in the Mf and As values; from Figure 4 It can be seen that the Ni prepared in Comparative Example 1 after heat treatment 45 Co5Mn 42 The Ms, Mf, As, and Af points of the Sn8 alloy are 274℃, 249℃, 261℃, and 286℃, respectively. Compared to Example 2, the phase transformation temperature range of Comparative Example 1 is significantly reduced.

[0080] Experimental Example 2:

[0081] The high-damping Ni-Co-Mn-Sn magnetic shape memory alloys prepared in Examples 1-3 and Comparative Example 1 were used for experiments.

[0082] Using wire cutting technology, the sample was cut into sheet-like samples with dimensions of 35×10×1mm. After the sheet-like samples were polished with sandpaper, their room temperature damping performance was tested using a Q800DMA. The experimental results are as follows. Figures 5-9 As shown.

[0083] from Figure 5 It can be seen that the Ni prepared in Example 1 45 Co5Mn 43 The damping properties of Sn7 alloy are positively correlated with strain amplitude. At low amplitudes, the damping properties of the alloy increase rapidly, reaching a maximum at a strain amplitude of 200 × 10⁻⁶. -6 At that time, its internal friction value Q⁻¹≈0.065. As the strain amplitude increases, the internal friction value tends to stabilize; from Figure 6 It can be seen that the Ni prepared in Example 1 45 Co5Mn 43The damping performance of Sn7 alloy varies with temperature. Within the temperature range of room temperature to 270℃, the alloy's damping performance remains constant. After 270℃, a phase transition occurs, and the phase transition damping mechanism becomes dominant, resulting in a very high level of damping performance. However, its temperature range is relatively narrow, limiting its application scope. Figure 7 As can be seen from Example 2, Ni 45 Co5Mn 42 The damping properties of Sn8 alloy are positively correlated with strain amplitude. At low amplitudes, the damping properties of the alloy increase rapidly, reaching a maximum at a strain amplitude of 200 × 10⁻⁶. -6 At that time, its internal friction value Q⁻¹≈0.062. As the strain amplitude increases, the internal friction value tends to stabilize; from... Figure 8 It can be seen that the Ni obtained in Example 3 45 Co5Mn 40 Sn 10 The damping properties of the alloy are positively correlated with the strain amplitude. At low amplitudes, the damping properties of the alloy increase rapidly, reaching a maximum at a strain amplitude of 200 × 10⁻⁶. -6 At that time, its internal friction value Q-1≈0.035. As the strain amplitude increases, the internal friction value increases slowly.

[0084] Ni prepared by comparison with Example 3 45 Co5Mn 40 Sn 10 Comparing the damping properties of the two alloys prepared in Examples 1 and 2, it can be found that the room temperature damping performance of the alloy is related to the phase transformation temperature of the alloy itself. In order to obtain an alloy with better damping performance, it is necessary to further increase the phase transformation temperature of the alloy.

[0085] from Figure 9 It can be seen that the Ni prepared in Comparative Example 1 after heat treatment 45 Co5Mn 42 The damping properties of Sn8 alloy are positively correlated with strain amplitude. At low amplitudes, the damping properties of the alloy increase rapidly, reaching a maximum at a strain amplitude of 200 × 10⁻⁶. -6 At that time, its internal friction value Q⁻¹≈0.047. As the strain amplitude increases, the internal friction value tends to stabilize. This is in contrast to the Ni prepared in Example 2. 45 Co5Mn 42 The damping performance of Sn8 alloy is significantly reduced compared to that of Comparative Example 1.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-damping Ni-Co-Mn-Sn magnetic shape memory alloy, characterized in that, The chemical formula is Ni 45 Co5Mn 43 Sn7, Ni 45 Co5Mn 42 Sn8 or Ni 45 Co5Mn 40 Sn 10 .

2. The process for the preparation of high damping Ni-Co-Mn-Sn magnetic shape memory alloy as claimed in claim 1, wherein, It comprises the following steps: According to the Ni 45 Co5Mn 43-x Sn 7+x The stoichiometric ratio of nickel, cobalt, manganese and tin is mixed and vacuum melted. After filling with inert gas, continue to melt, and finally cast.

3. The method of claim 2, wherein the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy is prepared by the following steps of: The purity of the nickel, cobalt, manganese and tin is greater than or equal to 99.9%. ​ 4. The method of claim 2, wherein the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy is prepared by the steps of: preparing a master alloy by mixing Ni, Co, Mn and Sn in a predetermined ratio; and performing a heat treatment on the master alloy at a temperature of 1,000°C to 1,200°C for 1 to 10 hours. The vacuum degree of the vacuum melting is less than 4.5 x 10 -3 Pa.

5. The method of claim 2, wherein the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy is prepared by the steps of: preparing a master alloy by mixing Ni, Co, Mn and Sn in a predetermined ratio; and performing a heat treatment on the master alloy at a temperature of 1,000°C to 1,200°C for 1 to 10 hours. The temperature of the vacuum melting and the continuous melting is 1500-1700 ℃.

6. The method of claim 2, wherein the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy is prepared by the steps of: The time of the vacuum melting and the continuous melting is 30-50 min.

7. The method for preparing the high-damping Ni-Co-Nn-Sn magnetic shape memory alloy according to claim 2, characterized in that, The pressure after filling the inert gas is 0.05-0.07 MPa.

8. The application of the high-damping Ni-Co-Mn-Sn magnetic shape memory alloy in claim 1 in shock absorption and noise reduction.

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