Ti-V-Nb-Zr-Fe-Cr high-entropy alloy and preparation method and application thereof

Abstract

The invention provides a Ti-V-Nb-Zr-Fe-Cr high-entropy alloy as well as a preparation method and application thereof, and belongs to the technical field of solid hydrogen storage. Six elements of Ti, V, Nb, Zr, Fe and Cr are adopted to form the TixVxNb10Zr10CryFey alloy, a component uniform design method is adopted, and the microstructure and the hydrogen storage performance of a Ti-V-based high-entropy hydrogen storage alloy system formed by different elements are controlled by fixing the content of Nb and Zr, limiting the content of Ti, V, Fe and Cr and limiting the ratio of x to y at the same time. The preparation cost of the alloy can be reduced, the effect of stabilizing the crystal structure of the'mixed entropy 'in the high-temperature environment can be fully played, and the method has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state hydrogen storage, and particularly to a Ti-V-Nb-Zr-Fe-Cr high-entropy alloy, a preparation method thereof, and an application thereof. Background Art

[0002] As one of the cleanest energy sources with the greatest development potential in the 21st century, hydrogen energy has attracted much attention due to its high calorific value and zero-carbon emission advantages. However, the low density of hydrogen under normal temperature and pressure poses a great challenge to its storage and transportation. The current mainstream hydrogen storage technologies can be divided into three categories: high-pressure gaseous hydrogen storage, cryogenic liquid hydrogen storage, and solid-state hydrogen storage based on hydrogen storage materials. Among these three technologies, solid-state hydrogen storage exhibits significant advantages due to its low operating pressure and high hydrogen purity, and has broad application prospects.

[0003] In the solid-state hydrogen storage technology, the metal hydride hydrogen storage method is currently the most widely used one. This technology realizes hydrogen storage by allowing hydrogen to penetrate into the alloy lattice to form metal hydrides under specific temperature and hydrogen pressure conditions. When hydrogen needs to be released, only the hydride needs to be heated. The uniqueness of this hydrogen storage method lies in that hydrogen exists in the alloy in atomic form, and its hydrogen storage density can reach 1000 times that of hydrogen under standard conditions, equivalent to or even higher than that of liquid hydrogen. Compared with other hydrogen storage technologies, the metal hydride hydrogen storage method shows obvious advantages in terms of safety, operation convenience, and environmental protection, providing an ideal solution for the storage and transportation of hydrogen energy.

[0004] However, the development of traditional hydrogen storage alloy systems has reached a bottleneck, and the method of improving hydrogen storage performance by trace doping elements has been difficult to meet the actual needs. Against this background, the concept of high-entropy alloys proposed in 2004 has opened up a new direction for the development of hydrogen storage materials. High-entropy alloys are composed of five or more equal or nearly equal metal elements, and the atomic percentage of each element ranges from 5% to 35%. Such alloys not only have a relatively high thermodynamic entropy value but also exhibit characteristics such as simple phase structure and flexible composition design, showing great application potential in the field of new energy hydrogen storage.

[0005] Ti-V-based hydrogen storage alloys have received extensive attention due to their excellent hydrogen storage characteristics. Their hydrogen storage capacity usually exceeds 2.0 wt.%, and some optimized alloys can even reach more than 3.0 wt.%. Such alloys can achieve reversible hydrogen absorption and desorption processes near room temperature, showing good kinetic performance and moderate operating conditions, and having significant application prospects. However, Ti-V-based alloys still face many challenges in practical applications, such as poor activation performance, high hydride stability, and high cost. In particular, the scarcity of vanadium elements limits their large-scale commercial applications. In recent years, researchers have optimized the performance of Ti-V-based alloys through various means. For example, by adding elements such as Cr, Fe, and Mn, the activation performance of the alloy has been significantly improved and the hydrogen desorption temperature has been reduced. At the same time, heat treatment and mechanical alloying technologies have been used to control the microstructure, further improving the hydrogen storage capacity. In addition, high-entropy alloy design and composite material development provide new research directions for Ti-V-based hydrogen storage materials. Therefore, it is of great significance to study new high-entropy alloys with excellent comprehensive hydrogen storage performance. Summary of the Invention

[0006] The purpose of the present invention is to provide a Ti-V-Nb-Zr-Fe-Cr high-entropy alloy, its preparation method and application, and the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy has excellent hydrogen storage performance.

[0007] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0008] The present invention provides a Ti-V-Nb-Zr-Fe-Cr high-entropy alloy, and its chemical composition is Ti x V x Nb 10 Zr 10 Cr y Fe y , where x and y are independently 5-35, and x / y = 0.6-7.0;

[0009] Based on the total amount of the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy being 100 at.%, the contents of Nb and Zr are both 10 at.%, and the contents of Ti, V, Fe, and Cr are independently 5-35 at%.

[0010] Preferably, x / y = 1.0-3.0.

[0011] The present invention provides a preparation method of the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy described in the above technical solution, including the following steps:

[0012] According to the required ratio of the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy, mix the metal raw materials Ti, V, Cr, Fe, Nb and Zr, and conduct vacuum melting to obtain the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy.

[0013] Preferably, before conducting the vacuum melting, evacuate to a vacuum degree ≤ 3×10-3 Pa, fill with argon, and conduct vacuum melting.

[0014] Preferably, the pressure of the vacuum melting is 0.8 bar.

[0015] Preferably, the number of times of the vacuum melting ≥ 4 times; the time of each vacuum melting is independently 30 - 45 s.

[0016] Preferably, the current of the vacuum melting is 20 - 80 A; the vacuum melting is conducted in a WK-II type non-consumable vacuum arc melting furnace.

[0017] The present invention provides the application of the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy described in the above technical solution or the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy prepared by the preparation method described in the above technical solution in the field of hydrogen storage.

[0018] Preferably, the method of the application includes: after activating the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy, conduct hydrogen absorption.

[0019] Preferably, the activation treatment is conducted under dynamic vacuum conditions at 673 K, and the time of the activation treatment is 2 h; the temperature of the hydrogen absorption is 303 K, and the pressure is 3 MPa.

[0020] The present invention provides a Ti-V-Nb-Zr-Fe-Cr high-entropy alloy. The present invention uses six elements Ti, V, Nb, Zr, Fe, and Cr to form Ti x V x Nb 10 Zr 10 Cr y Fe yAn alloy is designed by the method of uniform composition design. By fixing the contents of Nb and Zr at 10 at.%, restricting the contents of Ti, V, Fe, and Cr to be independently 5 - 35 at%, and controlling the ratio of x / y, the microstructure and hydrogen storage performance of the Ti-V-based high-entropy hydrogen storage alloy system formed by different elements are controlled. The partial substitution of Nb and Zr in the hydrogen storage alloy can effectively increase the lattice parameter and lattice distortion of the Ti-V-based alloy, increase the cycle durability while maintaining the hydrogen storage capacity, and the addition of Nb and Zr can make the alloy more easily activated to absorb hydrogen. By defining the contents of each element of the high-entropy alloy, the comprehensive performance of the Ti-V-based alloy can be improved while reducing the preparation cost of the alloy, and the role of "mixing entropy" in stabilizing the crystal structure at high temperature can be fully exerted, having broad application prospects.

[0021] The Ti provided by the present invention x V x Nb 10 Zr 10 Cr y Fe y (x and y are independently 5 - 35, and x / y = 0.6 - 7.0) The high-entropy alloy has the following advantages:

[0022] 1) It can be seen from the XRD characterization and EPMA scanning results that as the ratio of x / y increases, the phase structure of the alloy changes from a single Laves phase to a two-phase structure composed of Laves phase and BCC phase. The two-phase structure provides a channel for hydrogen atoms to enter the alloy, and the increase in the unit cell parameter provides more occupancy space for hydrogen atoms.

[0023] 2) Advantages in activation performance and hydrogen storage performance: Ti x V x Nb 10 Zr 10 Cr y Fe y The alloy can achieve hydrogen absorption after a single activation treatment. The alloy after the first activation can rapidly absorb hydrogen under the conditions of 3 MPa hydrogen pressure and room temperature. Among them, Ti 30 V 30 Nb 10 Zr 10 Cr 10 Fe 10 The alloy has a fast hydrogen absorption rate and can complete hydrogen absorption within 5 minutes.

[0024] 3) Ti 30 V 30 Nb 10 Zr 10 Cr 10 Fe 10 The high-entropy alloy has the advantage of hydrogen absorption kinetics: Ti 30 V30 Nb 10 Zr 10 Cr 10 Fe 10 After activation, the alloy can rapidly absorb hydrogen at room temperature under a hydrogen pressure of 3.0 MPa without an incubation period and can complete rapid hydrogen absorption within 5 minutes.

[0025] 4) Advantages of the alloy in hydrogen storage capacity: Ti 35 V 35 Nb 10 Zr 10 Cr 5 Fe 5 After the first activation treatment, the hydrogen storage capacity of the alloy can reach 2.66 wt.% under a hydrogen pressure of 3.0 MPa at room temperature, Ti 15 V 15 Nb 10 Zr 10 Cr 25 Fe 25 After 10 hydrogen absorption and desorption cycles, the hydrogen storage capacity of the alloy is as high as 2.09 wt.%, and the cycle retention rate can reach 92.1%. Description of the Drawings

[0026] Figure 1 XRD patterns of the Ti x V x Nb 10 Zr 10 Cr y Fe y (x / y = 0.6, 1.0, 3.0, 7.0) alloys prepared in Examples 1-4;

[0027] Figure 2 EPMA diagrams of the alloy ingots prepared in Examples 1-4; where (a) Ti 15 V 15 Nb 10 Zr 10 Cr 25 Fe 25 alloy; (b) Ti 20 V 20 Nb 10 Zr 10 Cr 20 Fe 20 alloy, (c) Ti 30 V 30 Nb 10 Zr 10 Cr 10 Fe 10 alloy, (d) Ti 35 V 35 Nb 10Zr 10 Cr 5 Fe 5 alloy;

[0028] Figure 3 Ti prepared for Examples 1 - 4 x V x Nb 10 Zr 10 Cr y Fe y (x / y = 0.6, 1.0, 3.0, 7.0) hydrogen absorption kinetic curves of the alloy;

[0029] Figure 4 Ti prepared for Examples 1 - 4 x V x Nb 10 Zr 10 Cr y Fe y (x / y = 0.6, 1.0, 3.0, 7.0) hydrogen absorption PCT curves of the alloy (a) x / y = 0.6, (b) x / y = 1.0, (c) x / y = 3.0, (d) x / y = 7.0;

[0030] Figure 5 Ti prepared for Examples 1 - 4 x V x Nb 10 Zr 10 Cr y Fe y (x / y = 0.6, 1.0, 3.0, 7.0) hydrogen storage capacity change curves of the alloy after 10 hydrogen absorption - desorption cycles. Detailed implementation manners

[0031] In the present invention, unless otherwise specified, the raw materials or reagents required for preparation are all commercially available products well - known to those skilled in the art.

[0032] The present invention provides a Ti - V - Nb - Zr - Fe - Cr high - entropy alloy, with the chemical composition of Ti x V x Nb 10 Zr 10 Cr y Fe y , where x and y are independently 5 - 35, and x / y = 0.6 - 7.0;

[0033] Based on the total amount of the Ti - V - Nb - Zr - Fe - Cr high - entropy alloy being 100 at.%, the contents of Nb and Zr are both 10 at.%, and the contents of Ti, V, Fe and Cr are independently 5 - 35 at%.

[0034] In the present invention, x is more preferably 15 to 30, further preferably 20 to 25, and y is preferably 10 to 30, further preferably 20 to 25.

[0035] In the present invention, it is more preferably that x / y = 1.0 to 3.0, and further preferably that x / y = 0.6, 1.0, 3.0 or 7.0.

[0036] The present invention provides a method for preparing the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy described in the above technical solution, comprising the following steps:

[0037] According to the required ratio of the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy, mix the metal raw materials Ti, V, Cr, Fe, Nb and Zr, and conduct vacuum melting to obtain the Ti-V-Nb-Zr-Fe-Cr high-entropy alloy.

[0038] In the present invention, the purity of the metal raw materials Ti, V, Cr, Fe, Nb and Zr is preferably ≥99.95%; the shapes of the metal raw materials Ti, V, Cr, Fe, Nb and Zr preferably include ingot shape, sheet shape or block shape.

[0039] In the present invention, the vacuum melting is preferably carried out in a WK-II type non-consumable vacuum arc melting furnace.

[0040] The present invention preferably uses a vice to shear the metal raw materials Ti, V, Cr, Fe, Nb and Zr to a diameter of 8 mm, accurately weigh each metal raw material using a Sartorius BSA2245 type electronic balance, and before putting the metal raw materials into the melting furnace, wipe the inside of the melting furnace with cotton dipped in anhydrous ethanol to ensure cleanliness.

[0041] The present invention preferably places the raw materials weighed according to the stoichiometric ratio in the pit of a water-cooled copper crucible, closes the furnace door, and successively conducts high-vacuum and low-vacuum pumping (the vacuum degree of high vacuum is 0.008 Pa, and the vacuum degree of low vacuum is 3 Pa) until the vacuum degree is lower than 3×10-3 Pa; then fill the furnace with high-purity Ar to near atmospheric pressure, and repeat the furnace washing 3 times to reduce the content of impurity gases, and then fill Ar to the required pressure.

[0042] In the present invention, before conducting the vacuum melting, it is preferably to pump the vacuum to a vacuum degree ≤3×10-3 Pa, fill with argon, and conduct the vacuum melting.

[0043] In the present invention, the pressure of the vacuum melting is preferably 0.8 bar (provided by argon), and the number of times of the vacuum melting ≥4 times; the time of each vacuum melting is independently 30 to 45 s. The present invention limits the number of times and time of the above vacuum melting to ensure the uniform composition of the alloy ingot.

[0044] In the present invention, the current of the vacuum melting is preferably 20 to 80A.

[0045] During the vacuum melting process, the non-consumable tungsten electrode is continuously rotated and the current is adjusted to reach the melting point of various metals to ensure sufficient flow of liquid phase on the surface of the alloy ingot, thereby promoting uniform diffusion of metal elements at high temperature.

[0046] After the vacuum smelting is completed, the present invention preferably cools the obtained sample with the furnace for 10 minutes, opens the smelting furnace, and obtains the alloy ingot.

[0047] After obtaining the alloy ingot, the present invention preferably uses a grinder to grind the surface of the alloy ingot to grind off the oxide layer, cuts it into small blocks with metal pliers, puts the block alloy into a metal mortar for grinding, and then sieves it to obtain a Ti-V-Nb-Zr-Fe-Cr high entropy alloy.

[0048] The present invention provides the application of the Ti-V-Nb-Zr-Fe-Cr high entropy alloy described in the above technical scheme or the Ti-V-Nb-Zr-Fe-Cr high entropy alloy prepared by the preparation method described in the above technical scheme in the field of hydrogen storage.

[0049] In the present invention, the application method preferably includes: absorbing hydrogen after activating the Ti-V-Nb-Zr-Fe-Cr high entropy alloy.

[0050] In the present invention, the activation treatment is preferably carried out under a dynamic vacuum condition of 673K, and the activation treatment time is 2h; the temperature of the hydrogen absorption is 303K and the pressure is 3MPa.

[0051] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified.

[0052] The following experimental methods and detection methods, unless otherwise specified, are conventional methods; the following reagents and raw materials, unless otherwise specified, are commercially available.

[0053] The elemental composition of the high entropy alloy in Examples 1 to 4 is shown in Table 1.

[0054] Table 1 High entropy alloy formula of Examples 1 to 4

[0055] x / y alloy Ti (at.%) V (at.%) Nb (at.%) Zr (at.%) Cr (at.%) Fe (at.%) 0.6 <![CDATA[Ti 15 V 15 Nb 10 Zr 10 Cr 25 Fe 25 > 15 15 10 10 25 25 1.0 <![CDATA[Ti 20 V 20 Nb 10 Zr 10 Cr 20 Fe 20 > 20 20 10 10 20 20 3.0 <![CDATA[Ti 30 V 30 Nb 10 Zr 10 Cr 10 Fe 10 > 30 30 10 10 10 10 7.0 <![CDATA[Ti 35 V 35 Nb 10 Zr 10 Cr 5 Fe 5 > 35 35 10 10 5 5

[0056] Example 1

[0057] Preparation of Ti15 V 15 Nb 10 Zr 10 Cr 25 Fe 25 High entropy alloy, that is, x / y=0.6.

[0058] The metal raw materials Ti, V, Cr, Fe, Nb and Zr were sheared to a diameter of 8 mm using vise jaws, and the metal raw materials Ti, V, Nb, Zr, Cr and Fe were weighed in turn using a Sartorius BSA2245 electronic balance, 0.4771 g, 0.5077 g, 0.6174 g, 0.6061 g, 0.9278 g and 0.8638 g, respectively, for a total of 4 g. The smelting furnace was wiped clean with cotton soaked in anhydrous ethanol, and the mixed metal raw materials were placed in a WK-Ⅱ non-consumable vacuum arc melting furnace for smelting, placed in a water-cooled copper crucible pit, and the furnace door was closed; high vacuum and low vacuum (the vacuum degree of high vacuum is 0.008 Pa, and the vacuum degree of low vacuum is 3 Pa) were drawn to a vacuum degree of less than 3×10 -3 Pa; fill with high-purity Ar to normal pressure, and repeat the chamber washing 3 times; fill with Ar to a pressure of 0.8 bar, continuously rotate the non-consumable tungsten electrode during smelting, and adjust the current from 20 to 80A to reach the melting point of various metal raw materials to ensure the flow of liquid phase on the surface of the alloy ingot, smelting for 40s each time, smelting for 4 times, and cooling with the furnace for 5min after smelting. Open the smelting furnace to obtain a button-shaped alloy ingot; then use a grinder to grind the surface of the alloy ingot to remove the oxide layer, use metal pliers to cut the alloy ingot into small pieces, put the block alloy into a metal mortar for grinding, and sieve the ground samples through 400-mesh and 100-mesh sieves respectively to obtain high entropy alloy samples.

[0059] The samples sieved through 400 mesh were subjected to XRD test, and the results showed that the phase structure of the alloy was Laves single phase structure ( Figure 1 ).

[0060] The 100-mesh sieved samples were subjected to EPMA testing to verify the phase structure of the alloy. The backscattered image of the alloy showed that ( Figure 2 ), Ti 15 V 15 Nb 10 Zr 10 Cr 25 Fe 25 The alloy has a single-phase structure, which is consistent with the XRD results.

[0061] The sieved 100-mesh sample was dynamically vacuum-activated at 673 K for 2 h. The alloy powder sample after activation treatment was placed in the test chamber of a hydrogen storage sorption instrument maintained at a constant temperature of 303 K. Subsequently, 3.0 MPa of high-purity hydrogen was charged and the system was sealed for hydrogen absorption kinetics testing. The test results showed that the kinetics of the alloy were improved ( Figure 3 ). Analyzing the reason, it was found that the Laves phase structure of the alloy catalyzed the addition of hydrogen atoms, thus improving the hydrogen absorption kinetics of the high-entropy alloy.

[0062] The sieved 100-mesh alloy sample was subjected to PCT testing at different temperatures (303 K, 333 K, 363 K) with a hydrogen pressure ranging from 0 to 3 MPa. It was found that the alloy had a relatively high hydrogen absorption plateau ( Figure 4 ), which was beneficial for the hydrogen desorption of the alloy.

[0063] The hydrogen storage capacity of the sieved 100-mesh alloy sample after 10 hydrogen absorption and desorption cycles was recorded. Hydrogen absorption was carried out under the above conditions (constant temperature of 303 K, 3.0 MPa). For hydrogen desorption, the sample saturated with hydrogen was placed in the sample chamber, and the temperature was raised from 303 K to 673 K, observing the change in hydrogen pressure in the sample chamber. The hydrogen absorption capacity is shown in Figure 5 . As can be seen from Figure 5 , the Ti 15 V 15 Nb 10 Zr 10 Cr 25 Fe 25 alloy had excellent cycling performance, and the hydrogen storage capacity retention rate after 10 cycles reached 92.1% ( Figure 5 ).

[0064] Example 2

[0065] The difference from Example 1 was only that: for the preparation of the Ti 20 V 20 Nb 10 Zr 10 Cr 20 Fe 20 high-entropy alloy, i.e., x / y = 1.0, a Sartorius BSA2245 type electronic balance was used to weigh 0.6410 g, 0.6821 g, 0.6220 g, 0.6107 g, 0.6963 g, and 0.7478 g of the metal raw materials Ti, V, Nb, Zr, Cr, and Fe respectively, with a total of 4 g.

[0066] The sieved 400-mesh sample was subjected to XRD testing, and the results showed that the phase structure of the alloy was a single Laves phase structure ( Figure 1 ).

[0067] The sieved 100-mesh sample was subjected to EPMA testing to verify the phase structure of the alloy. It can be observed from the backscattered image of the alloy that Ti 20 V 20 Nb 10 Zr 10 Cr 20 Fe 20 the alloy is a single-phase structure ( Figure 2 ), which is consistent with the XRD results.

[0068] The alloy powder sample after activating treatment of the sieved 100-mesh sample under the conditions in Example 1 was placed in the test chamber of a hydrogen storage sorption instrument at a constant temperature of 303 K. Subsequently, 3.0 MPa of high-purity hydrogen was charged and the system was sealed for hydrogen absorption kinetics testing. The test results found that the kinetics of the alloy was improved ( Figure 3 ). Analyzing the reason, it is that the Laves phase structure of the alloy plays a catalytic role in the addition of hydrogen atoms, thus improving the hydrogen absorption kinetics of the high-entropy alloy and increasing the maximum hydrogen storage capacity.

[0069] The sieved 100-mesh alloy sample was subjected to PCT testing according to the method in Example 1, and it was found that the hydrogen absorption plateau of the alloy was relatively high ( Figure 4 ), which is beneficial to the hydrogen desorption of the alloy.

[0070] The hydrogen storage capacity of the sieved 100-mesh alloy sample after 10 hydrogen absorption and desorption cycles according to the method in Example 1 was recorded. From Figure 5 it can be seen that Ti 20 V 20 Nb 10 Zr 10 Cr 20 Fe 20 the alloy has excellent cycling performance, and the hydrogen storage capacity retention rate after 10 cycles can reach 92.0%.

[0071] Example 3

[0072] The difference from Example 1 is only that: when preparing Ti 30 V 30 Nb 10 Zr 10 Cr 10 Fe 10 high-entropy alloy, that is, x / y = 3.0, a Sartorius BSA2245 type electronic balance was used to weigh 0.9763 g, 1.0389 g, 0.6316 g, 0.6201 g, 0.3535 g, and 0.3797 g of the metal raw materials Ti, V, Nb, Zr, Cr, and Fe respectively, totaling 4 g.

[0073] The sieved 400-mesh sample was subjected to XRD testing, and the test results found that the phase structure of the alloy consisted of two phases, the Laves phase and the BCC phase (Figure 1 )。

[0074] The sieved 100-mesh sample was subjected to EPMA testing to verify the phase structure of the alloy. It can be observed from the backscattered image of the alloy that Ti 30 V 30 Nb 10 Zr 10 Cr 10 Fe 10 the alloy is a two-phase structure ( Figure 2 ), which is consistent with the XRD results.

[0075] The alloy powder sample after activation treatment of the sieved 100-mesh sample under the conditions of Example 1 was placed in the test chamber of a hydrogen storage sorption instrument at a constant temperature of 303 K. Subsequently, 3.0 MPa of high-purity hydrogen was filled and the system was sealed for hydrogen absorption kinetics testing. The test results found that the kinetics of the alloy was improved ( Figure 3 ),Ti 30 V 30 Nb 10 Zr 10 Cr 10 Fe 10 the alloy can complete hydrogen absorption within 5 minutes. Analyzing the reason, it is that the two-phase structure of the alloy provides a large number of channels for the addition of hydrogen atoms. In addition, as the x / y ratio increases, the hydrogen-absorbing element content in the alloy increases, improving the hydrogen storage capacity of the alloy, and thus the maximum hydrogen storage capacity of the high-entropy alloy increases.

[0076] The sieved 100-mesh alloy sample was subjected to PCT testing according to the method of Example 1, and it was found that the hydrogen absorption plateau of the alloy decreased slightly ( Figure 4 ), which is beneficial for the alloy to absorb hydrogen at a lower hydrogen pressure.

[0077] The hydrogen storage capacity of the sieved 100-mesh alloy sample after 10 hydrogen absorption and desorption cycles according to the method of Example 1 was recorded. From Figure 5 it can be seen that Ti 30 V 30 Nb 10 Zr 10 Cr 10 Fe 10 the alloy has excellent cycling performance, and the hydrogen storage capacity after 10 cycles can reach 1.83 wt.%.

[0078] Example 4

[0079] The difference from Example 1 is only that: the preparation of Ti 35 V 35 Nb 10 Zr 10 Cr 5 Fe 5High-entropy alloy, where x / y = 7.0. Weigh the raw materials Ti, V, Nb, Zr, Cr, and Fe using a Sartorius BSA2245 electronic balance, which are 1.1478 g, 1.2214 g, 0.6365 g, 0.6249 g, 0.1781 g, and 0.1913 g respectively, with a total of 4 g.

[0080] Perform XRD testing on the sample sieved through 400 mesh. The test results show that the phase structure of the alloy consists of two phases, the Laves phase and the BCC phase ( Figure 1 ).

[0081] Perform EPMA testing on the alloy sample sieved through 100 mesh to verify the phase structure of the alloy. Through the backscattered image of the alloy, it can be observed that Ti 35 V 35 Nb 10 Zr 10 Cr 5 Fe 5 The alloy is a two-phase structure ( Figure 2 ), which is consistent with the XRD results.

[0082] Place the alloy powder sample after activation treatment of the alloy sample sieved through 100 mesh under the conditions of Example 1 into the test chamber of a constant-temperature 303K hydrogen storage adsorption instrument. Then, fill it with 3.0 MPa high-purity hydrogen and seal the system for hydrogen absorption kinetics testing. The test results show that the kinetics of the alloy is improved ( Figure 3 and Table 2). Analyze the reason that the two-phase structure of the alloy provides a large number of channels for the addition of hydrogen atoms. In addition, as the x / y ratio increases, the hydrogen-absorbing element content in the alloy increases, improving the hydrogen storage capacity of the alloy. Thus, the maximum hydrogen storage capacity of the high-entropy alloy increases. Ti 35 V 35 Nb 10 Zr 10 Cr 5 Fe 5 The hydrogen storage capacity of the alloy can reach 2.66 wt.%.

[0083] Table 2 Hydrogen absorption performance of high-entropy alloys in Examples 1-4

[0084]

[0085]

[0086] Perform PCT testing on the alloy sample sieved through 100 mesh according to the method of Example 1. It is found that the hydrogen absorption plateau of the alloy decreases slightly ( Figure 4 ), which is beneficial for the alloy to absorb hydrogen at a lower hydrogen pressure.

[0087] The hydrogen storage capacity of the alloy sample sieved through 100 meshes was recorded according to the method of Example 1 for 10 hydrogen absorption and desorption cycles. It can be seen from Figure 5 that the 35 Ti 35 V 10 Nb 10 Zr 5 Cr 5 Fe alloy has excellent cycling performance, and the hydrogen storage capacity after 10 cycles can reach 2.09 wt.%.

[0088] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A Ti-V-Nb-Zr-Fe-Cr high entropy alloy, characterized in that: The chemical composition is Ti x V x Nb 10 Zr 10 Cr y Fe y , wherein x and y are independently 5 to 35, and x / y = 0.6 to 7.0; Taking the total amount of the Ti-V-Nb-Zr-Fe-Cr high entropy alloy as 100 at.%, the contents of Nb and Zr are both 10 at.%, and the contents of Ti, V, Fe and Cr are independently 5 to 35 at.%.

2. The Ti-V-Nb-Zr-Fe-Cr high entropy alloy according to claim 1, characterized in that: x / y=1.0~3.

0.

3. The method for preparing the Ti-V-Nb-Zr-Fe-Cr high entropy alloy according to claim 1 or 2, characterized in that: The following steps are involved: According to the required proportion of the Ti-V-Nb-Zr-Fe-Cr high entropy alloy, metal raw materials Ti, V, Cr, Fe, Nb and Zr are mixed and vacuum smelted to obtain the Ti-V-Nb-Zr-Fe-Cr high entropy alloy.

4. The preparation method according to claim 3, characterized in that: Before the vacuum melting, the vacuum is evacuated to a vacuum degree of ≤3×10-3Pa, and argon is filled in to perform vacuum melting.

5. The preparation method according to claim 4, characterized in that: The pressure of the vacuum melting is 0.8 bar.

6. The preparation method according to claim 5, characterized in that: The vacuum melting is performed ≥4 times; and the time of each vacuum melting is independently 30 to 45 seconds.

7. The preparation method according to claim 6, characterized in that: The current of the vacuum melting is 20-80A; the vacuum melting is carried out in a WK-II type non-consumable vacuum arc melting furnace.

8. Application of the Ti—V—Nb—Zr—Fe—Cr high entropy alloy according to claim 1 or 2 or the Ti—V—Nb—Zr—Fe—Cr high entropy alloy prepared by the preparation method according to any one of claims 3 to 7 in the field of hydrogen storage.

9. The use according to claim 8, characterized in that: The application method comprises: activating the Ti-V-Nb-Zr-Fe-Cr high entropy alloy and then absorbing hydrogen.

10. The use according to claim 9, characterized in that: The activation treatment is carried out under a dynamic vacuum condition of 673K, and the activation treatment time is 2h; the temperature of the hydrogen absorption is 303K, and the pressure is 3MPa.

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