High-entropy alloy material and preparation method and application thereof

Abstract

The invention relates to the field of high-entropy alloy materials, and discloses a high-entropy alloy material and a preparation method and application thereof. The chemical formula of the high-entropy alloy material is MgaTibNbcZrdMe, wherein M is selected from at least one of Cr, Fe, Mn, Co, Ni, Cu and Al; wherein 1 < = a < = 1.5, 0.5 < = b < = 1, 0.5 < = c < = 1, 0.5 < = d < = 1, and 1 < = e < = 1.5. The high-entropy alloy material provided by the invention is uniform in structure component, small in grain size and excellent in hydrogen storage performance.

Description

Technical Field

[0001] The present invention relates to a high entropy alloy material, and in particular to a high entropy alloy material and a preparation method and application thereof. Background Art

[0002] Hydrogen is pollution-free and has a high calorific value. It is a clean energy with great development potential. Hydrogen storage and transportation is one of the main bottlenecks facing the hydrogen energy industry chain. Solid-state hydrogen storage has the advantages of high volume density and good safety, and is becoming a hot spot for hydrogen storage and transportation technology research and development and industrial layout.

[0003] Unlike traditional alloys based on one or two main elements, high entropy alloys usually contain five or more main elements in equal or nearly equal molar ratios. High entropy alloys are mainly characterized by the easy formation of simple phases due to the high entropy effect, severe lattice distortion due to differences in atomic radius, and the use of multiple elements greatly increases the possibility of developing material combinations with excellent hydrogen storage properties, which makes high entropy alloys theoretically considered to be very ideal hydrogen storage alloys.

[0004] At present, the research on hydrogen storage high entropy alloys is mainly focused on bulk high entropy alloys prepared by vacuum arc furnace melting. Since the solidification rate of this type of technology is usually not high, it is easy to cause component segregation and grain coarsening during the solidification process. In addition, when preparing refractory high entropy alloys with traditional casting technology, due to the high melting temperature of the elements, large differences in melting points, and different densities, it is impossible to simultaneously reach the temperature required for the diffusion of all element powder particles, and repeated melting is required, resulting in high production efficiency and low cost. The mechanical alloying method can be used to finely mix various elements and improve the activity of the mixed powder. The prepared high entropy alloy has the characteristics of uniform organizational composition and small grain size, which effectively reduces component segregation and has the advantages of low cost and safety. Although the current mechanical alloying method has many of the aforementioned advantages, it has the defect of low product preparation efficiency due to powder agglomeration and agglomeration during the preparation process.

[0005] CN112501485A discloses a reversible room temperature hydrogen storage high entropy alloy, the chemical formula of the high entropy alloy is recorded as TiaVbNbcCrdMy, M is at least one of Zr, Ni, Mn, Fe, Co, Mo, Al, Hf and Ta; wherein 5at%≤a≤40at%, 25at%≤b≤40at%, 5at%≤c≤30at%, 10at%≤d≤30at%, 0at%≤y≤20at%, and 60at%≤a+b+c≤85at% and a+b+c+d+y=100. However, when the alloy material prepared by this scheme is used, the activation temperature is high and the hydrogen storage capacity is low. Summary of the invention

[0006] The purpose of the present invention is to provide a high entropy alloy material with high hydrogen storage capacity.

[0007] In order to achieve the above-mentioned object, the first aspect of the present invention provides a high entropy alloy material, the chemical formula of which is Mg a Ti b Nb c Zr d M e , M is selected from at least one of Cr, Fe, Mn, Co, Ni, Cu, and Al;

[0008] Among them, 1≤a≤1.5, 0.5≤b≤1, 0.5≤c≤1, 0.5≤d≤1, 1≤e≤1.5.

[0009] Preferably, the chemical formula of the high entropy alloy material is Mg a Ti b Nb c Zr d M e , M is Mn, where 1.2≤a≤1.5, 0.8≤b≤1, 0.5≤c≤1, 0.8≤d≤1, 1≤e≤1.5.

[0010] Preferably, the entropy value of the high entropy alloy material is greater than 1.61R.

[0011] A second aspect of the present invention provides a method for preparing the high entropy alloy material according to the first aspect, the method comprising:

[0012] (1) Under an inert atmosphere, Mg, Ti, Nb, Zr and M are ball-milled to obtain powders;

[0013] (2) subjecting the powder to vacuum treatment to obtain a high entropy alloy material;

[0014] The conditions are controlled so that the chemical formula of the high entropy alloy material obtained is Mg a Ti b Nb c Zr d M e , M is selected from at least one of Cr, Fe, Mn, Co, Ni, Cu, and Al; wherein, 1≤a≤1.5, 1≤e≤1.5, 0.5≤b≤1, 0.5≤c≤1, and 0.5≤d≤1.

[0015] Preferably, the average particle diameters of the Mg single substance, the Ti single substance, the Nb single substance, the Zr single substance and the M single substance are each independently 25-45 μm.

[0016] Preferably, the conditions for the ball milling treatment include: a ball-to-material weight ratio of 20-30:1, a time of 50-100 hours, and a rotation speed of 300-500 rpm.

[0017] Preferably, the vacuum treatment conditions include: a vacuum degree of -100 KPa to -50 KPa, and a time of 0.5-1 h.

[0018] Further preferably, the ball milling process is performed in a forward and reverse rotation alternating manner.

[0019] In a preferred embodiment, the ball milling treatment comprises: performing cyclic ball milling treatment in a cycle of forward rotation for 8-12 minutes, rest for 8-12 minutes, reverse rotation for 8-12 minutes, and rest for 8-12 minutes.

[0020] Preferably, the diameters of the grinding balls used in the ball milling treatment are the same or different, and the diameters of the grinding balls are independently selected from 2-10 mm.

[0021] Preferably, in the ball milling process, the number ratio of the grinding balls 1 with a diameter of 9-10 mm, the grinding balls 2 with a diameter of 5-6 mm, and the grinding balls 3 with a diameter of 2-3 mm is 1:1.5-2:2.5-3.

[0022] The third aspect of the present invention provides application of the high entropy alloy material described in the first aspect in hydrogen storage.

[0023] The present invention has at least the following advantages:

[0024] (1) The high entropy alloy material provided by the present invention has uniform microstructure and composition, small grain size, and excellent hydrogen storage performance.

[0025] (2) The method for preparing the high entropy alloy material provided by the present invention is used to place each single substance powder in a ball mill. Under the operation of the ball mill, the powder and the grinding balls are subjected to long-term impact, collision and extrusion, so that the powder undergoes repeated deformation, cold welding and crushing, thereby realizing the solid-state diffusion of atoms in the powder and finally achieving alloying. It can maximize the solid solubility between elements and promote the formation of solid solution phase between alloy elements, which is beneficial to improving the hydrogen storage capacity of the high entropy alloy material. It also has the advantages of low cost, good safety and high product preparation efficiency. DETAILED DESCRIPTION

[0026] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0027] The forward rotation and the reverse rotation in the present invention refer to two rotation modes in opposite directions.

[0028] The ball-to-material weight ratio in the present invention refers to the weight ratio of the grinding balls to the raw materials.

[0029] In the present invention, the value of R is 8.314 J / (mol·K).

[0030] As mentioned above, the first aspect of the present invention provides a high entropy alloy material, the chemical formula of which is Mg a Ti b Nb c Zr d M e , M is selected from at least one of Cr, Fe, Mn, Co, Ni, Cu, and Al;

[0031] Among them, 1≤a≤1.5, 0.5≤b≤1, 0.5≤c≤1, 0.5≤d≤1, 1≤e≤1.5.

[0032] The present invention specifically selects Mg, Ti, Nb, and Zr as necessary components of the high entropy alloy material, and combines them with the M metal element to prepare an alloy material having excellent hydrogen absorption stability and a high hydrogen absorption capacity. The high entropy alloy material is prepared by preparing the aforementioned components according to the ratio required by the present invention, and can achieve an excellent effect of a hydrogen absorption capacity of more than 3wt%, preferably more than 3.2wt%.

[0033] Preferably, the chemical formula of the high entropy alloy material is Mg a Ti b Nb c Zr d M e , M is Mn, where 1.2≤a≤1.5, 0.8≤b≤1, 0.5≤c≤1, 0.8≤d≤1, 1≤e≤1.5.

[0034] Preferably, the entropy value of the high entropy alloy material is greater than 1.61R.

[0035] As mentioned above, the second aspect of the present invention provides a method for preparing the high entropy alloy material according to the first aspect, the method comprising:

[0036] (1) Under an inert atmosphere, Mg, Ti, Nb, Zr and M are ball-milled to obtain powders;

[0037] (2) subjecting the powder to vacuum treatment to obtain a high entropy alloy material;

[0038] The conditions are controlled so that the chemical formula of the high entropy alloy material obtained is Mg a Ti b Nb c Zr d Me , M is selected from at least one of Cr, Fe, Mn, Co, Ni, Cu, and Al; wherein, 1≤a≤1.5, 1≤e≤1.5, 0.5≤b≤1, 0.5≤c≤1, and 0.5≤d≤1.

[0039] Preferably, the average particle diameters of the Mg single substance, the Ti single substance, the Nb single substance, the Zr single substance and the M single substance are independently 25-45 μm, preferably 30-35 μm.

[0040] Preferably, in the present invention, the purity of each metal element in its elemental form is >99.9%.

[0041] Preferably, in step (1), the conditions of the ball milling treatment include: a ball-to-material weight ratio of 20-30:1, preferably 25-30:1; a time of 50-100h, preferably 80-100h; a rotation speed of 300-500rpm, preferably 400-500rpm.

[0042] According to a preferred specific implementation manner, the ball milling treatment is performed in a forward and reverse rotation alternating manner.

[0043] Further preferably, the ball milling treatment comprises: performing cyclic ball milling treatment with a cycle of forward rotation of 8-12 min, rest of 8-12 min, reverse rotation of 8-12 min, and rest of 8-12 min.

[0044] Preferably, the diameters of the grinding balls used in the ball milling treatment are the same or different, and the diameters of the grinding balls are independently selected from 2-10 mm.

[0045] More preferably, in the ball milling process, the ratio of the number of grinding balls 1 with a diameter of 9-10 mm, the number of grinding balls 2 with a diameter of 5-6 mm, and the number of grinding balls 3 with a diameter of 2-3 mm is 1:1.5-2:2.5-3. The inventors found in their research that the grinding ball combination under this preferred condition has high grinding efficiency and is conducive to grinding the single substance powder into fine particles, which is conducive to the process of mechanical alloying, thereby improving the hydrogen storage performance of the high entropy alloy material.

[0046] The present invention has no particular restrictions on the type and model of the ball milling equipment used for the ball milling treatment, as long as the aforementioned preferred parameter requirements of the present invention can be achieved. However, in order to obtain a high entropy alloy material with a higher hydrogen storage capacity, the present invention preferably uses the following method to perform the ball milling treatment.

[0047] According to a particularly preferred specific implementation manner, the Mg single substance, the Ti single substance, the Nb single substance, the Zr single substance, the M single substance and grinding balls are placed in a planetary ball mill; wherein the number and type of grinding balls in each ball mill jar are the same, and the ball-to-material weight ratio is 20-30:1; the planetary ball mill is started, the rotation speed is adjusted to 300-500rpm, and a cycle of forward rotation of 8-12min, intermittent rotation of 8-12min, reverse rotation of 8-12min, and intermittent rotation of 8-12min is used for cyclic ball milling treatment, and the ball milling time is 50-100h.

[0048] Preferably, the method of the present invention further comprises: before step (1), exhausting oxygen in the ball milling system and then performing the ball milling.

[0049] The present invention has no particular limitation on the specific method of exhausting oxygen, and those skilled in the art may select the method according to technical means known in the art. The present invention hereinafter provides an exemplary preferred specific implementation method, which should not be construed as a limitation on the present invention by those skilled in the art.

[0050] Preferably, in step (1), the inert atmosphere is an argon atmosphere.

[0051] Preferably, in step (2), the vacuum treatment conditions include: vacuum degree of -100KPa to -50KPa, time of 0.5-1h. The inventors found in their research that vacuum treatment of the powder obtained in step (1) can prevent oxidation of the powder during the grinding process, which is not conducive to hydrogen absorption performance.

[0052] The high entropy alloy material obtained by the preparation method provided by the present invention can be stored for more than 1 year under normal temperature and pressure without changing its hydrogen storage performance. The normal temperature and pressure in the present invention refers to 20-28°C and a standard atmospheric pressure.

[0053] As mentioned above, the third aspect of the present invention provides the use of the high entropy alloy material described in the first aspect in hydrogen storage.

[0054] Preferably, the application method comprises: subjecting the high entropy alloy material to an activation treatment and then using it for hydrogen storage; the activation treatment method comprises: performing a hydrogen absorption and desorption cycle at 180-220° C. for 1-3 times.

[0055] In the following examples, unless otherwise specified, the raw materials are all common commercially available products.

[0056] The average particle diameters of Mg simple substance, Ti simple substance, Nb simple substance, Zr simple substance, Mn simple substance, Fe simple substance, and V simple substance are each independently 30 μm.

[0057] Grinding ball combination 1: consists of grinding balls 1 with a diameter of 10 mm, grinding balls 2 with a diameter of 5 mm, and grinding balls 3 with a diameter of 3 mm in a quantity ratio of 1:1.5:3.

[0058] Grinding ball combination 2: consists of grinding balls 1 with a diameter of 10 mm, grinding balls 2 with a diameter of 5 mm, and grinding balls 3 with a diameter of 3 mm in a quantity ratio of 1:1:1.

[0059] Grinding ball combination 3: consists of grinding balls 1 with a diameter of 5 mm, grinding balls 2 with a diameter of 5 mm, and grinding balls 3 with a diameter of 3 mm in a quantity ratio of 1:1.5:3.

[0060] In the following examples, the chamber was evacuated and then filled with argon before ball milling, and this operation was repeated 4 times.

[0061] Example 1

[0062] (1) In an argon atmosphere, Mg, Ti, Nb, Zr, Mn (atomic molar ratio of 1.5:1:1:1:1) and grinding ball combination 1 are placed in a ball mill, with a ball-to-material weight ratio of 30:1. The ball mill is rotated at a speed of 500 rpm, with a cycle of forward rotation for 10 min, rest for 10 min, reverse rotation for 10 min, and rest for 10 min. The total working time is 100 h.

[0063] (2) The powder is subjected to vacuum treatment (vacuum degree is -100 KPa, time is 1 h) to obtain a high entropy alloy material.

[0064] Embodiment 2-9

[0065] Examples 2-9 were carried out using the same process as Example 1, with specific differences shown in Table 1 to obtain high entropy alloy materials.

[0066] Example 10

[0067] This embodiment adopts the high temperature smelting method, and the specific steps are as follows:

[0068] Under argon atmosphere, Mg, Ti, Nb, Zr and Mn with an atomic molar ratio of 1.5:1:1:1:1 are melted at high temperature in a vacuum arc melting furnace. After the raw materials are completely melted, they are cooled to obtain an alloy ingot, and the alloy ingot is repeatedly melted 4 times to obtain a high entropy alloy material.

[0069] Comparative Examples 1-3

[0070] Comparative Examples 1-3 were carried out using the same process as Example 1, with specific differences shown in Table 2 to obtain high entropy alloy materials.

[0071] Table 1

[0072]

[0073] Table 1

[0074]

[0075] Table 2

[0076]

[0077]

[0078] Test example:

[0079] The high entropy alloy materials prepared in Examples 1 to 10 and Comparative Examples 1-3 were tested for hydrogen absorption performance, and the test method was as follows:

[0080] (1) Activation of high entropy alloy materials: Activation is completed by absorbing and releasing hydrogen twice at 200°C.

[0081] (2) Hydrogen absorption PCT test: The activated high entropy alloy material was tested using a Sieverts-type PCT device at a test temperature of 473 K and a test pressure of 5 MPa.

[0082] The specific test data are shown in Table 3;

[0083] Table 3

[0084] Test items Hydrogen absorption / wt% Example 1 3.45 Example 2 3.40 Example 3 3.29 Example 4 3.01 Example 5 2.88 Example 6 2.71 Example 7 2.76 Example 8 2.87 Example 9 2.83 Example 10 2.25 Comparative Example 1 1.47 Comparative Example 2 1.73 Comparative Example 3 1.53

[0085] It can be seen from the above results that the high entropy alloy material of the present invention has uniform composition, small grain size, and excellent hydrogen storage performance. In addition, the preparation method provided by the present invention can maximize the solid solubility between elements, promote the formation of solid solution phase between alloy elements, and is conducive to improving the hydrogen storage capacity of high entropy alloy materials, and also has the advantages of low cost and good safety.

[0086] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A high entropy alloy material, characterized in that: The chemical formula of the high entropy alloy material is Mg a Ti b Nb c Zr d M e , M is selected from at least one of Cr, Fe, Mn, Co, Ni, Cu, and Al; Among them, 1≤a≤1.5, 0.5≤b≤1, 0.5≤c≤1, 0.5≤d≤1, 1≤e≤1.

5.

2. The high entropy alloy material according to claim 1, characterized in that: The chemical formula of the high entropy alloy material is Mg a Ti b Nb c Zr d M e , M is Mn, where 1.2≤a≤1.5, 0.8≤b≤1, 0.5≤c≤1, 0.8≤d≤1, 1≤e≤1.

5.

3. The high entropy alloy material according to claim 1 or 2, characterized in that: The entropy value of the high entropy alloy material is greater than 1.61R.

4. A method for preparing the high entropy alloy material according to any one of claims 1 to 3, characterized in that: The method includes: (1) Under an inert atmosphere, Mg, Ti, Nb, Zr and M are ball-milled to obtain powders; (2) subjecting the powder to vacuum treatment to obtain a high entropy alloy material; The conditions are controlled so that the chemical formula of the high entropy alloy material obtained is Mg a Ti b Nb c Zr d M e , M is selected from at least one of Cr, Fe, Mn, Co, Ni, Cu, and Al; wherein, 1≤a≤1.5, 1≤e≤1.5, 0.5≤b≤1, 0.5≤c≤1, and 0.5≤d≤1.

5. The method according to claim 4, characterized in that The average particle diameters of the Mg single substance, the Ti single substance, the Nb single substance, the Zr single substance and the M single substance are each independently 25-45 μm.

6. The method according to claim 4 or 5, characterized in that: The conditions of the ball milling treatment include: a ball-to-material weight ratio of 20-30:1, a time of 50-100 hours, and a rotation speed of 300-500 rpm; And / or, the conditions of the vacuum treatment include: a vacuum degree of -100 KPa to -50 KPa, and a time of 0.5-1 h.

7. The method according to claim 4 or 5, characterized in that: The ball milling process is carried out in a forward and reverse rotation alternating manner; Preferably, the ball milling treatment comprises: performing cyclic ball milling treatment in a cycle of forward rotation for 8-12 minutes, rest for 8-12 minutes, reverse rotation for 8-12 minutes, and rest for 8-12 minutes.

8. The method according to claim 4 or 5, characterized in that: The diameters of the grinding balls used in the ball milling process are the same or different, and the diameters of the grinding balls are independently selected from 2-10 mm.

9. The method according to claim 8, characterized in that In the ball milling process, the number ratio of the grinding balls 1 with a diameter of 9-10 mm, the grinding balls 2 with a diameter of 5-6 mm, and the grinding balls 3 with a diameter of 2-3 mm is 1:1.5-2:2.5-3.

10. Use of the high entropy alloy material according to any one of claims 1 to 3 in hydrogen storage.

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