A refractory high-entropy alloy with a layered heterostructure, its preparation method, and its application.

Abstract

This invention provides a refractory high-entropy alloy with a layered heterostructure, its preparation method, and its applications, belonging to the technical field of lightweight refractory high-entropy alloys. This invention selects low-density, high-melting-point Ti, Nb, and Zr as main elements, adds V to synergistically with Al to achieve a lightweighting effect, controls the content of each element to reduce the alloy's phase separation tendency, maintains a single body-centered cubic disordered solid solution, utilizes the uneven deformation during cold rolling to form high dislocation density deformation bands, and adds Ni to promote preferential nucleation and growth of these deformation bands during recrystallization annealing, thereby obtaining a layered heterostructure with bimodal grains, improving its plasticity while ensuring the alloy's strength.

Description

Technical Field

[0001] This invention belongs to the technical field of lightweight refractory high-entropy alloys, specifically relating to a refractory high-entropy alloy with a layered heterostructure, its preparation method, and its application. Background Technology

[0002] The application of traditional metallic structural materials in aerospace, weaponry, and other fields has always faced the dual contradiction of "strength and toughness versus lightness." In existing technologies, increasing strength through alloying often leads to increased density (e.g., nickel-based superalloys have a density of 8.5 g / cm³), while traditional lightweight designs (such as titanium alloys) struggle to balance room-temperature mechanical properties and formability. Therefore, there is an urgent need to design and develop new alloy materials with lower density and higher strength and toughness to meet the increasingly stringent comprehensive performance requirements of load-bearing materials for next-generation key high-end equipment in aviation, aerospace, marine, and nuclear power industries.

[0003] Refractory high-entropy alloys, composed of various refractory metals, have attracted widespread attention in the industry due to their high strength, high hardness, and excellent radiation resistance. However, these alloys generally have high densities, and their body-centered cubic (BCC) structure results in poor intrinsic work hardening. Furthermore, the current mainstream equiatomic ratio design principle does not take into account the presence of intermetallic compounds. Consequently, most refractory high-entropy alloys exhibit brittleness or rapid strain softening at room temperature, significantly limiting their engineering applications. Therefore, further reducing the density and improving the plasticity of refractory high-entropy alloys has become a major challenge for the industry. Summary of the Invention

[0004] The purpose of this invention is to provide a refractory high-entropy alloy with a layered heterostructure, its preparation method, and its applications. The refractory high-entropy alloy provided by this invention has low density and high elongation.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a refractory high-entropy alloy with a layered heterostructure, wherein the chemical formula of the refractory high-entropy alloy with the layered heterostructure is Ti. a Nb b Zr c V d Al e Ni f Among them, 25.0at%≤a≤40.0at%, 20.0at%≤b≤30.0at%, 25.0at%≤c≤40.0at%, 4at%≤d≤14.0at%, 0at%≤e≤7at%, 0at%<f≤2at% and a+b+c+d+e+f=100%;

[0007] The preparation method of the refractory high-entropy alloy with a layered heterostructure includes the following steps:

[0008] (1) The alloy raw materials are melted and then cast to obtain alloy ingots;

[0009] (2) The alloy ingot obtained in step (1) is subjected to homogenization treatment to obtain a homogenized alloy;

[0010] (3) The homogenized alloy obtained in step (2) is subjected to cold rolling deformation to obtain the rolled alloy;

[0011] (4) The rolled alloy obtained in step (3) is subjected to recrystallization annealing to obtain a refractory high entropy alloy with a layered heterostructure.

[0012] Preferably, the melting current in step (1) is 400~550A.

[0013] Preferably, the homogenization temperature in step (2) is 1100~1200℃ and the homogenization time is 1~2h.

[0014] Preferably, the homogenization treatment temperature is 1150~1200℃, and the homogenization treatment time is 1.5~2h.

[0015] Preferably, in step (3), the rolling rate of cold rolling deformation is 0.1~0.3m / s, the total reduction of cold rolling deformation is ≥80%, and the single reduction of cold rolling deformation is 1~3%.

[0016] Preferably, the rolling rate of the cold rolling deformation is 0.15~0.25m / s, the total reduction of the cold rolling deformation is 80~90%, and the single reduction of the cold rolling deformation is 2~3%.

[0017] Preferably, the rolling rate of the cold rolling deformation is 0.2 m / s, and the single reduction of the cold rolling deformation is 2.5%.

[0018] Preferably, the recrystallization annealing temperature in step (4) is 800~850℃ and the recrystallization annealing time is 0.5~1.5h.

[0019] Preferably, the recrystallization annealing treatment is performed at a temperature of 800~850℃ for 1 hour.

[0020] The present invention also provides the application of the refractory high-entropy alloy with layered heterostructure described in the above technical solution in aviation, aerospace, marine, nuclear power and weaponry.

[0021] This invention provides a refractory high-entropy alloy with a layered heterostructure, wherein the chemical formula of the refractory high-entropy alloy with the layered heterostructure is Ti. a Nb b Zr c V d Al e Ni f , wherein 25.0at%≤a≤40.0at%, 20.0at%≤b≤30.0at%, 25.0at%≤c≤40.0at%, 4at%≤d≤14.0at%, 0at%≤e≤7at%, 0at%<f≤2at% and a+b+c+d+e+f=100%; the preparation method of the refractory high entropy alloy with layered heterostructure includes the following steps: (1) melting the alloy raw materials and casting them to obtain an alloy ingot; (2) homogenizing the alloy ingot obtained in step (1) to obtain a homogenized alloy; (3) cold rolling the homogenized alloy obtained in step (2) to obtain a rolled alloy; (4) recrystallizing and annealing the rolled alloy obtained in step (3) to obtain a refractory high entropy alloy with layered heterostructure. This invention selects low-density, high-melting-point Ti, Nb, and Zr as main elements, and adds V to synergistically with Al to achieve a lightweighting effect. Controlling the content of each element reduces the tendency of alloy phase separation, maintaining a single BCC disordered solid solution. High dislocation density deformation bands are formed during cold rolling deformation, and Ni is added to promote preferential nucleation and growth of these deformation bands during recrystallization annealing, thereby obtaining a layered heterostructure with bimodal grains. This improves the alloy's plasticity while ensuring its strength. The results of the embodiments show that the density of the refractory high-entropy alloy provided by this invention is 6.55 g / cm³. 3 The following properties have a yield strength of over 1000 MPa, a tensile strength of over 1020 MPa, and an elongation at break of over 23%, with a maximum of 45%. Attached Figure Description

[0022] Figure 1 The images show the XRD patterns of the refractory high-entropy alloys with layered heterostructures in Examples 1-5.

[0023] Figure 2 Metallographic photograph of the refractory high-entropy alloy with a layered heterostructure in Example 1;

[0024] Figure 3 Metallographic photograph of the refractory high-entropy alloy with a layered heterostructure in Example 2;

[0025] Figure 4 Metallographic photograph of the refractory high-entropy alloy with a layered heterostructure in Example 3;

[0026] Figure 5Metallographic photograph of the refractory high-entropy alloy with a layered heterostructure in Example 4;

[0027] Figure 6 Metallographic photograph of the refractory high-entropy alloy with a layered heterostructure in Example 5;

[0028] Figure 7 The tensile engineering stress-engineering strain curves are shown for the refractory high-entropy alloys with layered heterostructures in Examples 1-5. Detailed Implementation

[0029] This invention provides a refractory high-entropy alloy with a layered heterostructure, wherein the chemical formula of the refractory high-entropy alloy with the layered heterostructure is Ti. a Nb b Zr c V d Al e Ni f Among them, 25.0at%≤a≤40.0at%, 20.0at%≤b≤30.0at%, 25.0at%≤c≤40.0at%, 4at%≤d≤14.0at%, 0at%≤e≤7at%, 0at%<f≤2at% and a+b+c+d+e+f=100%;

[0030] The preparation method of the refractory high-entropy alloy with a layered heterostructure includes the following steps:

[0031] (1) The alloy raw materials are melted and then cast to obtain alloy ingots;

[0032] (2) The alloy ingot obtained in step (1) is subjected to homogenization treatment to obtain a homogenized alloy;

[0033] (3) The homogenized alloy obtained in step (2) is subjected to cold rolling deformation to obtain the rolled alloy;

[0034] (4) The rolled alloy obtained in step (3) is subjected to recrystallization annealing to obtain a refractory high entropy alloy with a layered heterostructure.

[0035] The chemical formula of the refractory high-entropy alloy with a layered heterostructure provided by this invention is Ti. a Nb b Zr c V d Al e Ni f .

[0036] In this invention, 25.0at% ≤ a ≤ 40.0at%. As one embodiment, a can specifically be 25at%, 26at%, 27at%, 28at%, 29at%, 30at%, 31at%, 32at%, 33at%, 34at%, 35at%, 36at%, 37at%, 38at%, 39at%, or 40at%. In this invention, the density of Ti is 4.5 g / cm³. 3 It is significantly lower than that of traditional refractory metals (such as W, which has a concentration of 19.3 g / cm³). 3 Ta's 16.6 g / cm 3 Ti provides a lightweight base for the alloy, and the addition of Ti can improve the intrinsic plasticity of the alloy. However, the addition of Ti will reduce the stability of the matrix BCC. Therefore, the present invention controls the Ti content within the above range to ensure both the lightweight nature of the alloy and the phase stability of the alloy.

[0037] In this invention, 20.0at% ≤ b ≤ 30.0at%. As one embodiment, b can specifically be 20at%, 21at%, 22at%, 23at%, 24at%, 25at%, 26at%, 27at%, 28at%, 29at%, or 30at.

[0038] In this invention, 25.0at% ≤ c ≤ 40.0at%. As one embodiment, c can specifically be 25at%, 26at%, 27at%, 28at%, 29at%, 30at%, 31at%, 32at%, 33at%, 34at%, 35at%, 36at%, 37at%, 38at%, 39at%, or 40at.

[0039] In this invention, Zr and Nb are important elements for forming intermetallic compounds. Zr and Nb can cause severe lattice distortion in refractory high-entropy alloys, resulting in solid solution strengthening. Both are BCC stabilizing elements, which can effectively suppress Ti-induced phase transformation and grain growth, and improve the heat treatment stability of the alloy. At the same time, the mixing enthalpy between Zr and Nb is positive. Compared with adding one of the elements alone, the synergistic addition of the two is conducive to the uniform distribution of elements in the alloy and avoids brittle fracture caused by local element enrichment. However, Zr and Nb have high densities. Therefore, this invention controls the content of Zr and Nb within the above range to ensure both the lightweight nature of the alloy and the mechanical properties of the alloy.

[0040] In this invention, 4at% ≤ d ≤ 14.0at%. As one embodiment, d can specifically be 4at%, 5at%, 6at%, 7at%, 8at%, 9at%, 10at%, 11at%, 12at%, 13at%, or 14at%. In this invention, V has a lower density than Zr and Nb. Adding V can reduce the alloy density. Simultaneously, V is a stabilizing element in the BCC phase, and its addition does not cause significant phase separation like Al. By controlling the V content, a portion of V is added to replace Al, synergistically achieving a lightweight effect. Therefore, this invention controls the V content within the above range, ensuring both the lightweight nature of the alloy and its phase stability.

[0041] In this invention, 0at% ≤ e ≤ 7at%. As one embodiment, e can specifically be 0at%, 1at%, 2at%, 3at%, 4at%, 5at%, 6at%, or 7at%. In this invention, Al and Zr have a relatively negative enthalpy of mixing, and Al's atomic size is much smaller than that of Zr and other refractory elements. Adding Al often results in a large atomic size mismatch in the alloy system, leading to the formation of a second phase, etc. Although this can improve the room temperature strength of the alloy to some extent, it also seriously affects the alloy's plasticity. Therefore, this invention controls the Al content within the above-mentioned range to improve the alloy's plasticity while ensuring its strength.

[0042] In this invention, 0 at% < f ≤ 2 at%. As one embodiment, f can specifically be 1 at% or 2 at%. In this invention, adding a small amount of Ni significantly reduces the recrystallization energy barrier of grains near the rolling deformation zone, promoting preferential nucleation and growth of the deformation zone during recrystallization. However, its mixing enthalpy with Zr is negative, and excessive Ni will lead to the precipitation of a brittle second phase that severely degrades plasticity, and its density is high. Therefore, this invention controls the Ni content within the above range, ensuring both the lightweight nature of the alloy and its plasticity.

[0043] In this invention, the method for preparing the refractory high-entropy alloy with a layered heterostructure includes the following steps:

[0044] (1) The alloy raw materials are melted and then cast to obtain alloy ingots;

[0045] (2) The alloy ingot obtained in step (1) is subjected to homogenization treatment to obtain a homogenized alloy;

[0046] (3) The homogenized alloy obtained in step (2) is subjected to cold rolling deformation to obtain the rolled alloy;

[0047] (4) The rolled alloy obtained in step (3) is subjected to recrystallization annealing to obtain a refractory high entropy alloy with a layered heterostructure.

[0048] This invention involves melting and casting alloy raw materials to obtain alloy ingots.

[0049] In this invention, the alloy raw material preferably includes Ti particles, Nb particles, Zr particles, V particles, and Ni particles. When the Al content is not zero, it also preferably includes Al particles. This invention does not impose any special limitation on the particle size of the alloy raw material; commercially available products well-known to those skilled in the art can be used.

[0050] In this invention, the purity of the alloy raw material is preferably ≥99.9%.

[0051] The present invention does not impose any special limitation on the amount of Ti particles, Nb particles, Zr particles, V particles and Ni particles used, but can determine the amount based on the content of each element in the product.

[0052] When the Al content is not 0, this invention preferably weighs out an additional 5 at% of Al particles according to the Al content in the product. This is because Al has a low melting point and its boiling point is close to that of Nb. Therefore, an additional 5 at% of Al particles is weighed out.

[0053] In this invention, the alloy raw material is preferably subjected to sanding, ultrasonic cleaning with anhydrous ethanol, and drying in sequence before use.

[0054] The present invention does not have any special limitations on the operation of sanding, ultrasonic cleaning with anhydrous ethanol and drying. The oxide scale and stains on the surface of the alloy raw material can be removed and dried to constant weight by means of technical solutions known to those skilled in the art.

[0055] In one implementation, the melting is carried out in a vacuum arc melting furnace or a vacuum induction melting furnace. The present invention does not specify a particular model of the vacuum arc melting furnace or vacuum induction melting furnace; commercially available equipment well known to those skilled in the art can be used.

[0056] In this invention, when the Al content is not 0, the Al and V particles are preferably placed at the bottom of the crucible, the Ti and Ni particles are preferably placed above the Al and V particles, and the Zr and Nb particles are preferably placed above the Ti and Ni particles; when the Al content is 0, the V particles are preferably placed at the bottom of the crucible, the Ti and Ni particles are preferably placed above the V particles, and the Zr and Nb particles are preferably placed above the Ti and Ni particles. This invention places the lower-melting-point Al and V particles at the bottom of the crucible and the higher-melting-point Zr and Nb particles at the top, which is more conducive to the smelting of the alloy raw materials.

[0057] The present invention preferably involves evacuating the smelting furnace to a vacuum level of 2×10⁻⁶. -3 ~3×10 -3 The process involves first introducing high-purity argon gas (purity ≥ 99.99%) to a vacuum level of 0.02~0.05MPa (i.e., one gas intake), then repeating the gas intake process 1~3 times before smelting. This invention, by incorporating and controlling the number of gas intake cycles, can further reduce the impact of oxygen on the alloy.

[0058] In this invention, the melting is preferably carried out in a high-purity argon atmosphere; the pressure of the argon is preferably 0.02~0.05MPa.

[0059] In this invention, the number of melting operations is preferably 4 to 6, more preferably 5; after each melting operation, the ingot is preferably flipped 180° for the next melting operation; the current for each melting operation is preferably 400 to 550 A; and the time for each melting operation is preferably 2 to 4 minutes. As one embodiment, the current for each melting operation can specifically be 400 A, 410 A, 420 A, 430 A, 440 A, 450 A, 460 A, 470 A, 480 A, 490 A, 500 A, 510 A, 520 A, 530 A, 540 A, or 550 A; and the time for each melting operation can specifically be 2 minutes, 3 minutes, or 4 minutes. By controlling the melting current, time, and number of melting operations within the above ranges, this invention ensures that the raw materials are fully melted and mixed uniformly.

[0060] The present invention does not impose any special limitations on the casting operation; any casting technique known to those skilled in the art can be used.

[0061] The present invention does not impose any special limitations on the shape and size of the alloy ingot; it can be selected according to actual needs. As one embodiment, the alloy ingot may specifically be an alloy bar.

[0062] After obtaining the alloy ingot, the present invention performs homogenization treatment on the alloy ingot to obtain a homogenized alloy.

[0063] In this invention, the preferred temperature for the homogenization treatment is 1100~1200℃; the preferred time for the homogenization treatment is 1~2 hours. As one embodiment, the specific temperature for the homogenization treatment can be 1100℃, 1110℃, 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, or 1200℃; the specific time for the homogenization treatment can be 1 hour, 1.5 hours, or 2 hours. By controlling the temperature and time of the homogenization treatment within the above ranges, this invention can further improve the uniformity of the alloy.

[0064] In this invention, the homogenization process is preferably carried out in air, vacuum, or a protective atmosphere.

[0065] The present invention does not impose any special limitation on the vacuum degree of the vacuum; any vacuum conditions well known to those skilled in the art can be used.

[0066] The present invention does not have any particular limitation on the type of protective atmosphere; any protective atmosphere known to those skilled in the art can be used.

[0067] The present invention preferably places the alloy ingot into a quartz glass tube, then seals the tube with a hydrogen flame, and then performs homogenization treatment.

[0068] After the homogenization process is completed, the present invention preferably quenches and polishes the homogenized product in sequence to obtain a homogenized alloy.

[0069] The present invention does not impose any special limitations on the water quenching operation; water quenching to room temperature can be performed using a water quenching technique well known to those skilled in the art.

[0070] The present invention does not impose any special limitations on the grinding operation; any grinding technique known to those skilled in the art can be used to grind away the alloy surface layer.

[0071] After obtaining the homogenized alloy, the present invention performs cold rolling deformation on the homogenized alloy to obtain the rolled alloy.

[0072] In this invention, the preferred temperature for cold rolling is room temperature; the preferred rolling rate for cold rolling is 0.1~0.3 m / s; the preferred total reduction for cold rolling is ≥80%; and the preferred reduction per pass for cold rolling is 1~3%. As one embodiment, the preferred rolling rate for cold rolling can be 0.1 m / s, 0.15 m / s, 0.2 m / s, 0.25 m / s, or 0.3 m / s; the preferred total reduction for cold rolling can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, or 90%; and the preferred reduction per pass for cold rolling can be 1%, 2%, or 3%. This invention utilizes the uneven deformation during cold rolling to form high dislocation density deformation bands. In the subsequent recrystallization annealing process, Ni promotes the preferential nucleation and growth of the deformation bands, thereby obtaining a layered heterostructure microstructure composed of bimodal grains. By controlling the parameters of cold rolling deformation, the plasticity of the alloy is further improved while ensuring its strength.

[0073] After obtaining the rolled alloy, the present invention performs recrystallization annealing treatment on the rolled alloy to obtain a refractory high-entropy alloy with a layered heterostructure.

[0074] In this invention, the recrystallization annealing temperature is preferably 800~850℃; the recrystallization annealing time is preferably 0.5~1.5h; and the recrystallization annealing is preferably performed under vacuum conditions. As one embodiment, the recrystallization annealing temperature can specifically be 800℃, 810℃, 820℃, 830℃, 840℃, or 850℃; and the recrystallization annealing time can specifically be 0.5h, 1h, or 1.5h. This invention does not have a specific limitation on the vacuum degree; vacuum conditions well known to those skilled in the art can be used.

[0075] The present invention preferably places the rolled alloy into a quartz glass tube, then seals the tube with a hydrogen flame, and then performs recrystallization annealing treatment.

[0076] After recrystallization annealing, the present invention preferably quenches the product of recrystallization annealing in water to obtain a refractory high-entropy alloy with a layered heterostructure.

[0077] The present invention does not impose any special limitations on the water quenching operation; water quenching to room temperature can be performed using a water quenching technique well known to those skilled in the art.

[0078] In existing technologies, conventional lightweight refractory high-entropy alloys are mainly alloyed using the lightweight element Al. On the one hand, Al's low density contributes to weight reduction; on the other hand, the addition of Al reduces the BCC (Browser-Cooled Corner) stability region of the matrix, and heat treatment can achieve phase separation of the second phase, which, while improving strength, is a measure that sacrifices ductility for strength. This invention, however, does not utilize conventional alloying methods with high lightweight elements. It controls the Al content to maintain the BCC structure of the matrix and limit phase separation. However, the biggest problem with low Al content is insufficient weight reduction and inadequate mechanical properties. To address this issue, this invention optimizes the alloying elements and corresponding heat treatment processes to form a special structure: a layered heterostructure composed of bimodal grains. Strength is provided through back stress strengthening, while the layered grain boundaries act as dislocation sources, improving dislocation multiplication ability and ductility. This ensures that the alloy possesses both high strength and high ductility, and the process is simple and controllable.

[0079] This invention selects low-density, high-melting-point Ti, Zr, and Nb as main elements, and adds V to assist Al in achieving a lightweight effect. Compared with existing lightweight refractory high-entropy alloys, it has a lower tendency for phase separation and can maintain a single BCC disordered solid solution. It creatively introduces a layered heterostructure into the lightweight refractory high-entropy alloy, utilizing the high dislocation density deformation bands formed by uneven deformation during cold rolling. By adding Ni, the deformation bands preferentially nucleate and grow during recrystallization, thus obtaining a layered heterostructure composed of bimodal grains, resolving the contradiction of strength-plasticity imbalance in conventional phase separation strategies. The alloy provided by this invention not only has a low density but also excellent mechanical properties. The alloy exhibits good tensile plasticity at room temperature, with a yield strength exceeding 1000 MPa and a fracture elongation of up to 45%, achieving a strong-plasticity match in the lightweight refractory high-entropy alloy. This also facilitates subsequent processing and deformation, enabling large-size fabrication.

[0080] The present invention also provides the application of the refractory high-entropy alloy with layered heterostructure described in the above technical solution in aviation, aerospace, marine, nuclear power and weaponry.

[0081] The present invention does not impose any special limitations on the operation of the application, and any technical solution known to those skilled in the art can be used.

[0082] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0083] Example 1

[0084] A refractory high-entropy alloy with a layered heterostructure and the chemical formula Ti 25 Nb 30 Zr 40 V4Ni1;

[0085] The preparation method of the refractory high entropy alloy with layered heterostructure is as follows: (1) According to the alloy ratio, select Ti particles and Ni particles with a purity of 99.9% and Nb particles, Zr particles and V particles with a purity of 99.95%, and polish them with 120#, 320# and 600# SiC sandpaper in sequence. Then, use anhydrous ethanol for ultrasonic cleaning for 10 min, dry at 50℃, put the treated alloy raw materials into a vacuum arc melting furnace, with V particles at the bottom, Ti particles and Ni particles in the middle, and Nb particles and Zr particles at the top. Evacuate the melting furnace to 3×10 -3Pa, high-purity argon gas (99.99% purity) is introduced to control the vacuum at 0.02 MPa (considered as one gas intake). After three gas intakes, high-purity argon gas (99.99% purity) is introduced to a pressure of 0.02 MPa before melting. The melting time for each melting is 3 minutes, and the melting current is 400 A. The melting is repeated 5 times by flipping. Finally, the molten metal is poured into a mold to obtain alloy rods.

[0086] (2) Place the alloy rod obtained in step (1) into a quartz glass tube and evacuate the vacuum level of the glass tube to 2×10⁻⁶. 3 Below Pa, the tube is sealed with a hydrogen flame, homogenized at 1200℃ for 2 hours, cooled to room temperature by water quenching, and the surface thickness of 0.3 mm is removed by grinding to obtain the homogenized alloy.

[0087] (3) The homogenized alloy obtained in step (2) is subjected to cold rolling deformation. The temperature of cold rolling deformation is room temperature, the single reduction is 2.5%, the rolling speed is 0.2m / s, and the total reduction is 90%, to obtain the rolled alloy sheet.

[0088] (4) Place the rolled alloy sheet obtained in step (3) into a quartz glass tube and evacuate the vacuum level of the glass tube to 2×10⁻⁶. 3 Below Pa, the tube was sealed with a hydrogen flame, recrystallized and annealed at 800℃ for 1 hour, and then water-quenched to room temperature to obtain a refractory high-entropy alloy with a layered heterostructure.

[0089] Example 2

[0090] A refractory high-entropy alloy with a layered heterostructure and the chemical formula Ti 40 Nb 20 Zr 25 V 14 Ni1;

[0091] The preparation method of the refractory high-entropy alloy with layered heterostructure is the same as in Example 1.

[0092] Example 3

[0093] A refractory high-entropy alloy with a layered heterostructure and the chemical formula Ti 35 Nb 25 Zr 25 V 10 Al4Ni1;

[0094] The preparation method of the refractory high entropy alloy with layered heterostructure is as follows: (1) According to the alloy ratio, select Ti particles and Ni particles with a purity of 99.9% and Nb particles, Zr particles and V particles with a purity of 99.95%. Weigh out 5 at% Al particles according to the Al content in the alloy ratio. Use 120#, 320# and 600# SiC sandpaper to polish the surface in sequence. Then use anhydrous ethanol to perform ultrasonic cleaning for 10 min. Dry at 50℃. Put the treated alloy raw materials into a vacuum arc melting furnace. Al particles and V particles are at the bottom, Ti particles and Ni particles are in the middle, and Nb particles and Zr particles are at the top. Evacuate the furnace to 3×10 -3 Pa, high-purity argon gas (99.99% purity) is introduced to control the vacuum at 0.02 MPa (considered as one gas intake). After three gas intakes, high-purity argon gas (99.99% purity) is introduced to a pressure of 0.02 MPa before melting. The melting time for each melting is 3 minutes, and the melting current is 400 A. The melting is repeated 5 times by flipping. Finally, the molten metal is poured into a mold to obtain alloy rods.

[0095] (2) Place the alloy rod obtained in step (1) into a quartz glass tube and evacuate the vacuum level of the glass tube to 2×10⁻⁶. 3 Below Pa, the tube is sealed with a hydrogen flame, homogenized at 1200℃ for 2 hours, cooled to room temperature by water quenching, and the surface thickness of 0.3 mm is removed by grinding to obtain the homogenized alloy.

[0096] (3) The homogenized alloy obtained in step (2) is subjected to cold rolling deformation. The temperature of cold rolling deformation is room temperature, the single reduction is 2.5%, the rolling speed is 0.2m / s, and the total reduction is 90%, to obtain the rolled alloy sheet.

[0097] (4) Place the rolled alloy sheet obtained in step (3) into a quartz glass tube and evacuate the vacuum level of the glass tube to 2×10⁻⁶. 3 Below Pa, the tube was sealed with a hydrogen flame, recrystallized and annealed at 800℃ for 1 hour, and then water-quenched to room temperature to obtain a refractory high-entropy alloy with a layered heterostructure.

[0098] Example 4

[0099] A refractory high-entropy alloy with a layered heterostructure and the chemical formula Ti 35 Nb 25 Zr 25 V6Al7Ni2;

[0100] The preparation method of the refractory high-entropy alloy with layered heterostructure is the same as in Example 3.

[0101] Example 5

[0102] A refractory high-entropy alloy with a layered heterostructure and the chemical formula Ti 35 Nb 25 Zr 25 V6Al7Ni2;

[0103] The preparation method of the refractory high entropy alloy with layered heterostructure is as follows: (1) According to the alloy ratio, select Ti particles and Ni particles with a purity of 99.9% and Nb particles, Zr particles and V particles with a purity of 99.95%. Weigh out 5 at% Al particles according to the Al content in the alloy ratio. Use 120#, 320# and 600# SiC sandpaper to polish the surface in sequence. Then use anhydrous ethanol to perform ultrasonic cleaning for 10 min. Dry at 50℃. Put the treated alloy raw materials into a vacuum arc melting furnace. Al particles and V particles are at the bottom, Ti particles and Ni particles are in the middle, and Nb particles and Zr particles are at the top. Evacuate the furnace to 3×10 -3 Pa, high-purity argon gas (99.99% purity) is introduced to control the vacuum at 0.02 MPa (considered as one gas intake). After three gas intakes, high-purity argon gas (99.99% purity) is introduced to a pressure of 0.02 MPa before melting. The melting time for each melting is 3 minutes, and the melting current is 400 A. The melting is repeated 5 times by flipping. Finally, the molten metal is poured into a mold to obtain alloy rods.

[0104] (2) Place the alloy rod obtained in step (1) into a quartz glass tube and evacuate the vacuum level of the glass tube to 2×10⁻⁶. 3 Below Pa, the tube is sealed with a hydrogen flame, homogenized at 1200℃ for 2 hours, cooled to room temperature by water quenching, and the surface thickness of 0.3 mm is removed by grinding to obtain the homogenized alloy.

[0105] (3) The homogenized alloy obtained in step (2) is subjected to cold rolling deformation. The temperature of cold rolling deformation is room temperature, the single reduction is 2.5%, the rolling speed is 0.2m / s, and the total reduction is 80%, to obtain the rolled alloy sheet.

[0106] (4) Place the rolled alloy sheet obtained in step (3) into a quartz glass tube and evacuate the vacuum level of the glass tube to 2×10⁻⁶. 3 Below Pa, the tube was sealed with a hydrogen flame, recrystallized and annealed at 850°C for 1 hour, and then water-quenched to room temperature to obtain a refractory high-entropy alloy with a layered heterostructure.

[0107] The XRD patterns of the refractory high-entropy alloys with layered heterostructures in Examples 1-5 are shown below. Figure 1 As shown. From Figure 1 As can be seen from the examples, the alloys in the examples are all single-phase BCC structures.

[0108] Metallographic photographs of the refractory high-entropy alloys with layered heterostructures in Examples 1-5 are shown below. Figures 2-6 As shown. From Figures 2-6 As can be seen, the coarse grains, fine grains, and rolling deformation bands of the alloy are distributed in layers.

[0109] The tensile stress-strain curves of the refractory high-entropy alloys with layered heterostructures in Examples 1-5 are shown below. Figure 7 As shown. From Figure 7 As can be seen, the alloy has a yield strength exceeding 1000 MPa and a fracture elongation of up to 45%.

[0110] The hardness was tested using an HVS-1000A Vickers hardness tester with a load of 1 kg. Five points were marked and the average value was taken.

[0111] The density was tested using Archimedes' displacement method. The dry weight of the alloy entity was obtained by weighing it using an electronic balance of model MSA324S-000-DU. Then, the alloy entity was completely immersed in distilled water to calculate its actual volume and thus its actual density.

[0112] According to the national standard "Metallic materials - Tensile testing - Part 1: Test at room temperature" (GB / T 228.1-2021), a quasi-static tensile test was conducted on the alloy using an electronic universal testing machine, and the average yield strength, tensile strength and elongation at break of five identically treated samples were taken.

[0113] The hardness, density, yield strength, tensile strength and elongation at break of the refractory high-entropy alloys with layered heterostructures in Examples 1-5 are shown in Table 1.

[0114] Table 1. Hardness, density, yield strength, tensile strength, and elongation at break of the refractory high-entropy alloys with layered heterostructures in Examples 1-5.

[0115]

[0116] As can be seen from Table 1, the high-entropy alloy provided by the present invention has a low density, high hardness, and high yield strength, tensile strength and elongation at break.

[0117] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A refractory high-entropy alloy with a layered heterostructure, characterized in that, The chemical formula of the refractory high-entropy alloy with a layered heterostructure is Ti. a Nb b Zr c V d Al e Ni f Among them, 25.0at%≤a≤40.0at%, 20.0at%≤b≤30.0at%, 25.0at%≤c≤40.0at%, 4at%≤d≤14.0at%, 0at%≤e≤7at%, 1at%≤f≤2at% and a+b+c+d+e+f=100at%; The preparation method of the refractory high-entropy alloy with a layered heterostructure includes the following steps: (1) The alloy raw materials are melted and then cast to obtain alloy ingots; (2) The alloy ingot obtained in step (1) is subjected to homogenization treatment to obtain a homogenized alloy; (3) The homogenized alloy obtained in step (2) is subjected to cold rolling deformation to obtain the rolled alloy; (4) The rolled alloy obtained in step (3) is subjected to recrystallization annealing to obtain a refractory high entropy alloy with a layered heterostructure.

2. The refractory high-entropy alloy with a layered heterostructure according to claim 1, characterized in that, The current for melting in step (1) is 400~550A.

3. The refractory high-entropy alloy with a layered heterostructure according to claim 1, characterized in that, The homogenization temperature in step (2) is 1100~1200℃, and the homogenization time is 1~2h.

4. The refractory high-entropy alloy with a layered heterostructure according to claim 3, characterized in that, The homogenization process is carried out at a temperature of 1150~1200℃ for 1.5~2 hours.

5. The refractory high-entropy alloy with a layered heterostructure according to claim 1, characterized in that, In step (3), the rolling rate of cold rolling deformation is 0.1~0.3m / s, the total reduction of cold rolling deformation is ≥80%, and the single reduction of cold rolling deformation is 1~3%.

6. The refractory high-entropy alloy with a layered heterostructure according to claim 5, characterized in that, The rolling rate of the cold rolling deformation is 0.15~0.25m / s, the total reduction of the cold rolling deformation is 80~90%, and the single reduction of the cold rolling deformation is 2~3%.

7. The refractory high-entropy alloy with a layered heterostructure according to claim 6, characterized in that, The rolling rate of the cold rolling deformation is 0.2 m / s, and the single reduction of the cold rolling deformation is 2.5%.

8. The refractory high-entropy alloy with a layered heterostructure according to claim 1, characterized in that, The recrystallization annealing temperature in step (4) is 800~850℃, and the recrystallization annealing time is 0.5~1.5h.

9. The refractory high-entropy alloy with a layered heterostructure according to claim 8, characterized in that, The recrystallization annealing treatment is performed at a temperature of 800~850℃ for 1 hour.

10. The application of the refractory high-entropy alloy with layered heterostructure as described in any one of claims 1 to 9 in aviation, aerospace, marine, nuclear power and weaponry.

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