Ni-Mn-Ti-Si alloy material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of thermoelastic refrigeration alloy materials and preparation processes of alloys of the thermoelastic refrigeration alloy materials. The material can obtain remarkable adiabatic temperature change near the room temperature, and is an ideal near-room-temperature elastic heat refrigerating working medium. The chemical formula of the Ni-Mn-Ti-Si elastic thermal refrigeration alloy material is Ni < 50-x > Mn < 3 2.5-y > Ti < 17.5 + y > Si < x >, the sum of mole numbers of elements in the alloy is 100, x is larger than or equal to 1 and smaller than or equal to 4, and y is larger than or equal to 0 and smaller than or equal to 2.5. According to the preparation method, the Ni-Mn-Ti-Si elastic thermal refrigeration alloy block blank is prepared through raw material proportioning, vacuum arc repeated smelting, polycrystalline cast ingot preparation, annealing under the protection of high-purity inert gas and then rapid water cooling. Under the action of external stress, the adiabatic temperature change range of the alloy block ranges from 2.4 K to 15.1 K, and the adiabatic temperature change range ranges from-2.0 K to-14.8 K.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy materials, and relates to a Ni-Mn-Ti-Si alloy material, a preparation method and applications thereof. Background Art

[0002] With the rapid growth of demand for industrial and commercial refrigeration, innovation in refrigeration technology has been greatly promoted. However, widely used volatile liquid refrigerants (such as hydrofluorocarbons) may trigger the greenhouse effect when released into the atmosphere, leading to global environmental degradation. In the process of seeking environmentally friendly refrigeration technology, solid-state caloric cooling technology based on the caloric effect (eCE) of solid materials driven by uniaxial stress is regarded as a promising solution. Among the various caloric cooling materials currently under research, Heusler-type Ni-Mn-Ti shape memory alloys have attracted much attention due to their large phase transition entropy change and low raw material cost. However, the poor mechanical properties of the ternary Ni-Mn-Ti alloy limit the realization of its caloric effect and high cyclic stability. Therefore, the design is to replace the Mn element by Si to regulate the alloy microstructure, thereby improving the caloric cooling performance of the Mn-Ni-Ti-Si alloy. Summary of the Invention

[0003] The present invention provides a Ni-Mn-Ti-Si alloy material, a preparation method and application thereof, so as to overcome the deficiencies in the prior art.

[0004] In order to achieve the aforementioned object of the invention, the technical solution adopted by the present invention includes:

[0005] A Ni-Mn-Ti-Si alloy material, the chemical formula of the alloy material is Ni 50-x Mn 32.5-y Ti 17.5+ y Si x , the sum of the molar numbers of elements in the alloy is 100, where 1≤x≤4, 0≤y≤2.5.

[0006] Further features, in the Ni-Mn-Ti-Si alloy material, Ni is 99.99wt.% high-purity Ni, Mn is 99.9wt.% high-purity Mn, Ti is 99.99wt.% high-purity Ti, and Si is 99.9wt.% high-purity Si.

[0007] Further features, the Ni-Mn-Ti-Si alloy material has an adiabatic temperature change range of 2.4 to 15.1K and -2.0 to -14.8K under external compressive stress, and a maximum recoverable strain of 2.5% to 4%, which can be used for elastic caloric cooling.

[0008] A method for preparing a Ni-Mn-Ti-Si alloy material comprises the following steps:

[0009] (1) Raw material ratio: According to the chemical formula Ni 50-x Mn 32.5-y Ti 17.5+y Si x The molar ratio of the ingredients is 100, and the sum of the molar numbers of the elements in the alloy is 100, where 1≤x≤4, 0≤y≤2.5;

[0010] (2) Preparation of polycrystalline ingots: The raw materials weighed in step (1) were placed in a water-cooled copper crucible in a vacuum arc melting furnace, and the chamber of the arc melting furnace was evacuated to 3×10 -3 After the inert protective gas reaches 0.05 MPa, the smelting is repeated 4 times for 1 to 1.5 hours. Arc melting is performed under electromagnetic stirring to obtain a polycrystalline parent alloy with uniform composition.

[0011] (3) Heat treatment: The Ni-Mn-Ti-Si alloy ingot is kept at 950° C. for 24 hours and then water-cooled to obtain the Ni-Mn-Ti-Si elastic caloric refrigeration material.

[0012] A further feature is that in step (1), the method of placing Ni, Mn, Ti, and Si in the water-cooled copper crucible is to place Mn at the bottom of the water-cooled copper crucible, and Si and Ti are placed above Mn in sequence, with Ni placed at the top.

[0013] A further feature is that in step (2), the ingot is repeatedly smelted four times.

[0014] A further feature is that the inert gas in step (1) and step (2) is high-purity argon.

[0015] The beneficial effects of the present invention compared with the prior art are:

[0016] (1) By adjusting the ratio of alloy components, the Ni-Mn-Ti-Si alloy can undergo a reversible martensitic transformation over a wide temperature range. Driven by an external stress field, a stress-induced martensitic transformation occurs, exhibiting a large elastocaloric effect.

[0017] (3) The raw materials Ni, Mn, Ti, and Si required for the thermoelastic alloy provided by the present invention are inexpensive and abundant in reserves. Furthermore, the alloy is non-toxic, has good thermal conductivity, good cooling capacity, and good performance stability.

[0018] (3) The martensitic phase transformation temperature is adjusted by replacing Mn with Ti and Ni with Si. This method is simple and has good repeatability, and can produce near-room temperature elastocaloric cooling materials with excellent mechanical properties and a wide operating temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Ni in the embodiment of the present invention 49 Mn 32.5 Ti 17.5 DSC curve of Si1 material.

[0020] Figure 2 Ni in the embodiment of the present invention 48 Mn 32 Ti 18 DSC curve of Si2 material.

[0021] Figure 3 Ni in the embodiment of the present invention 47 Mn 31 Ti 19 DSC curve of Si3 material.

[0022] Figure 4 Ni in the embodiment of the present invention 46 Mn 30 Ti 20 DSC curve of Si4 material.

[0023] Figure 5 Ni in the embodiment of the present invention 49 Mn 32.5 Ti 17.5 Superelastic curve of Si1 material.

[0024] Figure 6 Ni in the embodiment of the present invention 48 Mn 32 Ti 18 Superelastic curve of Si2 material.

[0025] Figure 7 Ni in the embodiment of the present invention 47 Mn 31 Ti 19 Superelastic curve of Si3 material.

[0026] Figure 8 Ni in the embodiment of the present invention 46 Mn 30 Ti 20 Superelastic curve of Si4 material.

[0027] Figure 9 Ni in the embodiment of the present invention 49 Mn 32.5 Ti 17.5 ΔT of Si1 material ad -Time curve.

[0028] Figure 10 Ni in the embodiment of the present invention 48Mn 32 Ti 18 ΔT of Si2 material ad -Time curve.

[0029] Figure 11 Ni in the embodiment of the present invention 47 Mn 31 Ti 19 ΔT of Si3 material ad -Time curve.

[0030] Figure 12 Ni in the embodiment of the present invention 46 Mn 30 Ti 20 ΔT of Si4 material ad -Time curve. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are described in detail below in conjunction with the technical solutions and drawings.

[0032] In the following examples, Ni is 99.99 wt. % high-purity Ni, Mn is 99.9 wt. % high-purity Mn, Ti is 99.99 wt. % high-purity Ti, and Si is 99.9 wt. % high-purity Si.

[0033] In the following examples, the vacuum arc melting furnace was purchased from Shenyang Scientific Instrument Research and Development Center Co., Ltd., Chinese Academy of Sciences, and the model of the vacuum arc melting furnace was DHL-400.

[0034] The detection technology means of the following embodiments are:

[0035] Differential scanning calorimetry (DSC, TA-DSC25) was used to measure the martensitic transformation and reverse transformation temperatures of the samples. 49 Mn 32.5 Ti 17.5 Si1、Ni 48 Mn 32 Ti 18 Si2 and Ni 47 Mn 31 Ti 19 The heating and cooling rates of Si3 alloy were both 10K / min, and Ni 46 Mn 30 Ti 20 The heating and cooling rates of the Si4 sample were both 2 K / min, and the phase transition temperature was determined on the DSC curve using the tangent method.

[0036] The superelastic behavior and elastocaloric effect of the alloy were measured using an electronic universal testing machine (Shimadzu AGS-X / 50kN). The strain rate of the superelastic test was 5.6×10 -4 s -1 During the compression test, a displacement meter (Mitutoyo LG100-0110) was used to monitor the compressive strain of the sample. The alloy's caloric effect was directly measured using a K-type thermocouple attached to the sample surface, and a paperless recorder connected to the thermocouple recorded the temperature changes on the sample surface in real time. To ensure that the sample reached thermal equilibrium with the ambient temperature, the hold time between loading and unloading was set to 10 seconds. The strain rate for the caloric effect test was 5.6×10 -2 s -1 .

[0037] Example 1

[0038] Ni-Mn-Ti-Si alloy material, the sum of the molar numbers of elements in the alloy material is 100, and the molar ratio of the elements is Ni:Mn:Ti:Si=49:32.5:17.5:1.

[0039] The preparation method of the Ni-Mn-Ti-Si alloy material comprises the following steps:

[0040] Step 1, preparation of polycrystalline parent alloy:

[0041] (1) Raw material ratio: According to the chemical formula Ni 49 Mn 32.5 Ti 17.5 The molar ratio of Si1;

[0042] (2) Preparation of polycrystalline ingots: The raw materials weighed in step (1) were placed in a water-cooled copper crucible in a vacuum arc melting furnace, and the chamber of the arc melting furnace was evacuated to 3×10 -3 Then, an inert protective gas of 0.05 MPa is introduced and the smelting is repeated 4 times for 1 to 1.5 hours. Arc melting is performed under electromagnetic stirring to obtain a polycrystalline parent alloy with uniform composition.

[0043] (3) Heat treatment:

[0044] The Ni-Mn-Ti-Si alloy ingot was cast, kept at 950°C for 24 hours and then water-cooled to obtain the Ni 49 Mn 32.5 Ti 17.5 Si1 alloy material.

[0045] Differential scanning calorimetry was used to analyze the Ni 49 Mn 32.5 Ti 17.5 Phase transformation behavior of Si1 alloy. Figure 1 As shown, Ni 49 Mn 32.5 Ti 17.5 Si1 alloy showed significant endothermic and exothermic peaks during the heating and cooling processes, respectively, indicating that martensitic transformation and reverse martensitic transformation occurred within the test temperature range.

[0046] The superelastic behavior and elastocaloric effect of the samples were measured using an electronic universal testing machine. Figure 5 As shown in Figure 2, isothermal loading / unloading experiments were carried out at 293 K with a strain rate of 5.6×10 -4 s -1 The alloy exhibits a typical plateau-type superelastic response accompanied by significant stress hysteresis, with a maximum recoverable strain of 4%. The temperature change of the sample during the stress-induced phase transformation was directly measured using a thermocouple at a strain rate of 5.6×10 -2 s -1 .like Figure 9 As shown in Figure 2, the maximum adiabatic temperature changes of the alloy during loading and unloading are 15.1K and -14.8K, respectively.

[0047] Example 2

[0048] Ni-Mn-Ti-Si alloy material, the sum of the molar numbers of elements in the alloy material is 100, and the molar ratio of the elements is Ni:Mn:Ti:Si=48:32:18:2.

[0049] The preparation method of the Ni-Mn-Ti-Si alloy material comprises the following steps:

[0050] Step 1, preparation of polycrystalline parent alloy:

[0051] (1) Raw material ratio: According to the chemical formula Ni 48 Mn 32 Ti 18 The molar ratio of Si2;

[0052] (2) Preparation of polycrystalline ingots: The raw materials weighed in step (1) were placed in a water-cooled copper crucible in a vacuum arc melting furnace, and the chamber of the arc melting furnace was evacuated to 3×10 -3 Then, an inert protective gas of 0.05 MPa is introduced and the smelting is repeated 4 times for 1 to 1.5 hours. Arc melting is performed under electromagnetic stirring to obtain a polycrystalline parent alloy with uniform composition.

[0053] (3) Heat treatment:

[0054] The Ni-Mn-Ti-Si alloy ingot was cast, kept at 950°C for 24 hours and then water-cooled to obtain the Ni 48 Mn 32 Ti 18Si2 alloy material.

[0055] Differential scanning calorimetry was used to analyze the Ni 48 Mn 32 Ti 18 Phase transformation behavior of Si2 alloy. Figure 2 As shown, Ni 48 Mn 32 Ti 18 Si2 alloy showed significant endothermic and exothermic peaks during the heating and cooling processes, respectively, indicating that martensitic transformation and reverse martensitic transformation occurred within the test temperature range.

[0056] The superelastic behavior and elastocaloric effect of the samples were measured using an electronic universal testing machine. Figure 6 As shown in Figure 2, isothermal loading / unloading experiments were carried out at 293 K with a strain rate of 5.6×10 -4 s -1 The alloy exhibits a quasi-linear superelastic response with moderate stress hysteresis and a maximum recoverable strain of 3%. The temperature change of the sample during the stress-induced phase transformation was directly measured using thermocouples at a strain rate of 5.6×10 -2 s -1 .like Figure 10 As shown, the maximum adiabatic temperature changes of the alloy during loading and unloading are 7.6K and -6.7K respectively.

[0057] Example 3

[0058] Ni-Mn-Ti-Si alloy material, the sum of the molar numbers of elements in the alloy material is 100, and the molar ratio of the elements is Ni:Mn:Ti:Si=47:31:19:3.

[0059] The preparation method of the Ni-Mn-Ti-Si alloy material comprises the following steps:

[0060] Step 1, preparation of polycrystalline parent alloy:

[0061] (1) Raw material ratio: According to the chemical formula Ni 47 Mn 31 Ti 19 The molar ratio of Si3;

[0062] (2) Preparation of polycrystalline ingots: The raw materials weighed in step (1) were placed in a water-cooled copper crucible in a vacuum arc melting furnace, and the chamber of the arc melting furnace was evacuated to 3×10 -3 Then, an inert protective gas of 0.05 MPa is introduced and the smelting is repeated 4 times for 1 to 1.5 hours. Arc melting is performed under electromagnetic stirring to obtain a polycrystalline parent alloy with uniform composition.

[0063] (3) Heat treatment:

[0064] The Ni-Mn-Ti-Si alloy ingot was cast, kept at 950°C for 24 hours and then water-cooled to obtain the Ni 47 Mn 31 Ti 19 Si3 alloy material.

[0065] Differential scanning calorimetry was used to analyze the Ni 47 Mn 31 Ti 19 Phase transformation behavior of Si3 alloy. Figure 3 As shown, Ni 47 Mn 31 Ti 19 Si3 alloy showed significant endothermic and exothermic peaks during the heating and cooling processes, respectively, indicating that martensitic transformation and reverse martensitic transformation occurred within the test temperature range.

[0066] The superelastic behavior and elastocaloric effect of the samples were measured using an electronic universal testing machine. Figure 7 As shown in Figure 2, isothermal loading / unloading experiments were carried out at 293 K with a strain rate of 5.6×10 -4 s -1 The alloy exhibits a quasi-linear superelastic response with a small stress hysteresis and a maximum recoverable strain of 2.5%. The temperature change of the sample during the stress-induced phase transformation was directly measured using a thermocouple at a strain rate of 5.6×10 -2 s -1 .like Figure 11 As shown, the maximum adiabatic temperature changes of the alloy during loading and unloading are 3.4K and -3.0K respectively.

[0067] Example 4

[0068] Ni-Mn-Ti-Si alloy material, the sum of the molar numbers of elements in the alloy material is 100, and the molar ratio of the elements is Ni:Mn:Ti:Si=46:30:20:4.

[0069] The preparation method of the Ni-Mn-Ti-Si alloy material comprises the following steps:

[0070] Step 1, preparation of polycrystalline parent alloy:

[0071] (1) Raw material ratio: According to the chemical formula Ni 46 Mn 30 Ti 20 The molar ratio of Si4;

[0072] (2) Preparation of polycrystalline ingots: The raw materials weighed in step (1) were placed in a water-cooled copper crucible in a vacuum arc melting furnace, and the chamber of the arc melting furnace was evacuated to 3×10 -3 Then, an inert protective gas of 0.05 MPa is introduced and the smelting is repeated 4 times for 1 to 1.5 hours. Arc melting is performed under electromagnetic stirring to obtain a polycrystalline parent alloy with uniform composition.

[0073] (3) Heat treatment:

[0074] The Ni-Mn-Ti-Si alloy ingot was cast, kept at 950°C for 24 hours and then water-cooled to obtain the Ni 46 Mn 30 Ti 20 Si4 alloy material.

[0075] Differential scanning calorimetry was used to analyze the Ni 46 Mn 30 Ti 20 Phase transformation behavior of Si4 alloy. Figure 4 As shown, Ni 46 Mn 30 Ti 20 Si4 alloy showed significant endothermic and exothermic peaks during the heating and cooling processes, respectively, indicating that martensitic transformation and reverse martensitic transformation occurred within the test temperature range.

[0076] The superelastic behavior and elastocaloric effect of the samples were measured using an electronic universal testing machine. Figure 8 As shown in Figure 2, isothermal loading / unloading experiments were carried out at 293 K with a strain rate of 5.6×10 -4 s -1 The alloy exhibits a quasi-linear superelastic response with a small stress hysteresis and a maximum recoverable strain of 2.5%. The temperature change of the sample during the stress-induced phase transformation was directly measured using a thermocouple at a strain rate of 5.6×10 -2 s -1 .like Figure 12 As shown in Figure 3, the maximum adiabatic temperature changes of the alloy during loading and unloading are 2.4 K and -2.1 K, respectively.

Claims

1. A Ni-Mn-Ti-Si alloy material, characterized in that: The chemical formula of the alloy material is Ni 50-x Mn 32.5- y Ti 17.5+y Si x , the sum of the molar numbers of each element in the alloy is 100, where 1≤x≤4, 0≤y≤2.

5.

2. The Ni-Mn-Ti-Si alloy material according to claim 1, characterized in that Ni is 99.99 wt. % high-purity Ni, Mn is 99.9 wt. % high-purity Mn, Ti is 99.99 wt. % high-purity Ti, and Si is 99.9 wt. % high-purity Si.

3. The use of the Ni-Mn-Ti-Si alloy material according to claim 1 or 2, characterized in that: The Ni-Mn-Ti-Si alloy material has an adiabatic temperature change range of 2.4 to 15.1 K and -2.0 to -14.8 K under external compressive stress, a maximum recoverable strain of 2.5% to 4%, and can be used for elastic caloric cooling.

4. A method for preparing a Ni-Mn-Ti-Si alloy material, characterized in that: The following steps are involved: (1) Raw material ratio: According to the chemical formula Ni 50-x Mn 32.5-y Ti 17.5+y Si x The molar ratio of the ingredients is 100, and the sum of the molar numbers of the elements in the alloy is 100, where 1≤x≤4, 0≤y≤2.5; (2) Preparation of polycrystalline ingots: The raw materials weighed in step (1) were placed in a water-cooled copper crucible in a vacuum arc melting furnace, and the chamber of the arc melting furnace was evacuated to 3×10 -3 After the temperature reaches 0.05 MPa, an inert protective gas of 0.05 MPa is introduced, and the smelting is repeated 4 times for 1 to 1.5 hours; arc melting is performed under electromagnetic stirring to obtain a polycrystalline parent alloy with uniform composition; (3) Heat treatment: The Ni-Mn-Ti-Si alloy ingot was kept at 950° C. for 24 h and then water-cooled to obtain the Ni-Mn-Ti-Si elastic caloric refrigeration material.

5. The preparation method according to claim 4, characterized in that In step 3(1), the method for placing Ni, Mn, Ti, and Si in the water-cooled copper crucible is to place Mn at the bottom of the water-cooled copper crucible, and then place Si and Ti above Mn in sequence, with Ni being placed at the top.

6. The method for preparing Ni-Mn-Ti-Si according to claim 4 or 5, characterized in that: In the step (2), the ingot is repeatedly smelted 4 times.

7. The method for preparing Ni-Mn-Ti-Si according to claim 4 or 5, characterized in that: The inert gas in steps (1) and (2) is high-purity argon.

Images