Low-melting high-energy-release zirconium-titanium-nickel active medium-entropy alloy and preparation method thereof

Abstract

The application relates to the technical field of medium-entropy alloy, and discloses a low-melting-point high-energy-releasing zirconium-titanium-nickel active medium-entropy alloy and a preparation method thereof, which comprises the following steps: preparing raw materials, respectively taking granular pure titanium, granular pure zirconium and granular pure nickel according to preset atomic percentages; placing the raw materials in a non-consumable vacuum arc melting furnace and separately placing the preset titanium ingot in the furnace cavity, vacuumizing and introducing protective gas; melting the preset titanium ingot in the center of the furnace cavity to absorb residual oxygen, and the melting frequency is 1-5 times; after the arc is introduced, the melting current is kept at 190A-220A, electromagnetic stirring is supplemented, the mixed material of the granular pure titanium, the granular pure zirconium and the granular pure nickel is melted, the zirconium-nickel-titanium alloy is formed, the zirconium-nickel-titanium alloy is subjected to multiple melting, the melting time is controlled to be 2min-4min each time, each piece of alloy is subjected to melting for 4-8 times, and finally the alloy melt is rapidly cooled in a square water-cooled copper mold to be absorbed and cast into shape.

Description

Technical Field

[0001] The present invention relates to the technical field of medium-entropy alloys, and in particular to a zirconium-titanium-nickel active medium-entropy alloy with a low melting point and high energy release, and a preparation method thereof. Background Art

[0002] The field of warhead technology has developed rapidly in recent years. Energetic structural material warheads, as a new type of warhead, have garnered widespread attention due to their "structure-energy integration" characteristics. Compared to traditional inert material warheads, these not only rely on their own kinetic energy to penetrate the target, but also release energy through chemical reactions after impact, achieving secondary effects on the target. Among the many energetic structural materials, metallic energetic structural materials, due to their high strength, high density, and high energy release properties, have been shown to combine multiple destructive effects, such as penetration and combustion, and thus hold broad application prospects.

[0003] At present, the research on metallic energetic structural materials mainly focuses on systems such as tungsten-zirconium alloys, aluminum-based alloys, amorphous alloys, and medium- and high-entropy alloys. However, existing materials still have certain limitations: for example, tungsten-zirconium alloys have poor plasticity and insufficient mechanical bearing capacity; aluminum-based alloys have low density and limited penetration performance; amorphous alloys are difficult to form in large sizes due to complex preparation processes, making it difficult to meet the needs of industrial production. Medium- and high-entropy alloy energetic structural materials are expected to develop into highly efficient and destructive energetic structural materials due to their flexibility in composition design, excellent mechanical properties, and good energy release characteristics. Among them, medium-entropy alloys have fewer constituent elements, and their microstructure and performance control are simpler. Therefore, developing a medium-entropy alloy energetic structural material with excellent mechanical properties, high energy release characteristics, and good forming ability is of great significance for promoting the industrial application of this technology.

[0004] Furthermore, the existing preparation processes for medium- and high-entropy alloy energetic structural materials still leave room for improvement. For example, some alloy systems require complex melting techniques or multiple processing steps, resulting in high production costs and low efficiency. Furthermore, the materials are susceptible to contamination by impurities (such as oxygen and nitrogen) during the melting process, affecting their performance stability. Summary of the Invention

[0005] The present invention provides a low-melting-point, high-energy-release zirconium-titanium-nickel active medium-entropy alloy and a preparation method thereof. The preparation method has a simple process, controllable composition, and can effectively reduce the impurity content, thereby improving the comprehensive performance of the material and the feasibility of industrial application, and solving the technical problems of the shortcomings of existing materials in mechanical properties, energy release, and preparation process.

[0006] According to one aspect of the present invention, a method for preparing a zirconium-titanium-nickel active medium-entropy alloy with a low melting point and high energy release is provided, comprising the following steps: S100, preparing raw materials, and weighing granular pure titanium, granular pure zirconium, and granular pure nickel according to preset atomic percentages; S200, placing the raw materials in a non-consumable vacuum arc melting furnace, and separating them from the preset titanium ingots in the furnace chamber, evacuating the furnace, and introducing protective gas; S300, melting the preset titanium ingot in the center of the furnace chamber to absorb residual oxygen, and the melting number is 1 times-5 times; S400, after arc striking, the melting current is maintained at 190A-220A, and electromagnetic stirring is used to melt a mixture of granular pure titanium, granular pure zirconium and granular pure nickel, and the mixture is melted to form a zirconium-nickel-titanium alloy, and the formed zirconium-nickel-titanium alloy is melted multiple times, and the melting time of each time is controlled at 2min-4min, and each alloy is melted 4-8 times; S500, the melt is quickly cooled in a square water-cooled copper mold and suction-casted to obtain a zirconium-titanium-nickel active medium-entropy alloy with a low melting point and high energy release.

[0007] Furthermore, the number of smelting times in step S300 is 2 to 3 times.

[0008] Furthermore, in step S400, each alloy is melted 3 to 5 times.

[0009] Furthermore, in the electromagnetic stirring in step S400, the stirring current is 3A-8A, the single stirring time is 20S-50S, and it is repeated 3-5 times. The electromagnetic force is used to drive the melt to produce forced convection to eliminate component segregation, promote the discharge of residual oxygen in the melt, and reduce the smelting time.

[0010] Furthermore, the suction casting in step S500 is specifically as follows: the size of the square copper mold is 10 mm × 10 mm × 65 mm, and the cooling water temperature is 22° C. Rapid cooling promotes the martensitic phase transformation of the alloy and improves the mechanical properties of the alloy.

[0011] Furthermore, a pre-processing step S101 is added after step S100, in which the raw materials are ultrasonically cleaned with alcohol and dried.

[0012] Furthermore, the raw materials in step S100 are laboratory-grade pure zirconium, pure titanium and pure nickel, and the purity of pure zirconium, pure titanium and pure nickel are all 99.9%.

[0013] Furthermore, in step S200, the vacuum is pumped to 5×10 -3 Below Pa.

[0014] Furthermore, the protective gas introduced in step S200 is argon gas at 0.05 MPa.

[0015] According to another aspect of the present invention, a low-melting-point, high-energy-release zirconium-titanium-nickel active medium-entropy alloy is provided, which is prepared using the above-mentioned method for preparing the low-melting-point, high-energy-release zirconium-titanium-nickel active medium-entropy alloy.

[0016] Furthermore, the alloy is composed of the following elements in atomic percentage: 25%-75% zirconium, 5%-45% titanium, 10.5%-30% nickel, and the remainder is unavoidable impurities.

[0017] The present invention has the following beneficial effects:

[0018] 1. Improved composition uniformity: Through electromagnetic stirring technology, forced convection is generated in the melt during the smelting process, effectively suppressing component segregation and ensuring uniform distribution of alloy elements, thereby improving the mechanical properties and energy release stability of the material.

[0019] 2. Reduced impurity content: Using preset titanium ingots to absorb residual oxygen in the furnace chamber, combined with protective atmosphere melting, significantly reduces the content of impurities such as oxygen and nitrogen in the alloy, avoids the adverse effects of impurities on material properties, and improves the purity and reactivity of the alloy.

[0020] 3. Process efficiency optimization: By controlling the melting current, melting times and single melting time, the overall melting cycle can be shortened while ensuring full melting of the alloy, thereby improving production efficiency, reducing energy consumption, and being more suitable for industrial production.

[0021] 4. Enhanced comprehensive performance: The resulting zirconium-titanium-nickel active medium-entropy alloy has both low melting point and high energy release characteristics. In warhead applications, it can achieve the synergistic effect of efficient penetration and secondary energy release. At the same time, it has good forming ability and meets the needs of large-scale industrial production.

[0022] 5. High process controllability: By adjusting the melting parameters (such as current, stirring intensity, melting times, etc.), the microstructure and properties of the alloy can be flexibly controlled to adapt to the differentiated requirements of material properties in different application scenarios.

[0023] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 is an X-ray diffraction (XRD) test pattern of the zirconium-nickel-titanium alloy prepared in preferred embodiments 1-4 of the present invention;

[0026] Figure 2 are differential scanning calorimetry (DSC) test graphs of the zirconium nickel titanium alloy prepared in preferred embodiments 1-4 of the present application. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the following. The raw materials and reagents used in the following embodiments are commercially available or can be prepared by known methods, unless otherwise specified.

[0028] The preparation method of the low-melting-point high-energy-release zirconium titanium nickel active medium-entropy alloy of the present embodiment comprises the following steps: S100, preparing raw materials, and weighing granular pure titanium, granular pure zirconium, and granular pure nickel according to the preset atomic percentage; S200, placing the raw materials in a non-consumable vacuum arc melting furnace and separating them from the preset titanium ingot in the furnace chamber, vacuumizing, and introducing protective gas; S300, melting the preset titanium ingot in the center of the furnace chamber to absorb residual oxygen, and the number of melting times is 1-5 times; S400, after the arc is ignited, the melting current is maintained at 190A-220A, and electromagnetic stirring is assisted to melt the mixture of granular pure titanium, granular pure zirconium, and granular pure nickel, and the zirconium nickel titanium alloy is formed by melting, and the zirconium nickel titanium alloy is melted for multiple times, the melting time of each time is controlled within 2min-4min, and each piece of alloy is melted for 4-8 times; S500, the melt is rapidly cooled and suction cast into a square water-cooled copper mold to obtain a low-melting-point high-energy-release zirconium titanium nickel active medium-entropy alloy. The preparation method of the low-melting-point high-energy-release zirconium titanium nickel active medium-entropy alloy of the present application uses the preset titanium ingot to absorb the residual oxygen in the furnace chamber and combines with the protective atmosphere melting to significantly reduce the impurity content of oxygen, nitrogen, etc. in the alloy, avoid the adverse effects of impurities on the performance of the material, and improve the purity and reactivity of the alloy; by controlling the melting current, the number of melting times, and the single melting time, the overall melting cycle is shortened while ensuring the full melting of the alloy, the production efficiency is improved, and the energy consumption is reduced, which is more suitable for industrial production; through electromagnetic stirring technology, forced convection of the melt is generated in the melting process, the composition segregation is effectively inhibited, the uniform distribution of alloy elements is ensured, and the mechanical properties and energy release stability of the material are improved; by adjusting the melting parameters (such as current, stirring intensity, number of melting times, etc.), the microstructure and performance of the alloy can be flexibly controlled to adapt to the differentiated requirements of different application scenarios for material properties; the obtained zirconium titanium nickel active medium-entropy alloy has both low melting point and high energy release characteristics, and can realize the synergistic effect of high-efficiency penetration and secondary energy release in the warhead application, while having good forming ability, meeting the needs of large-scale industrial production. While simplifying the preparation process, the composition uniformity, purity, and comprehensive performance of the alloy are significantly improved, providing a better metal-type energetic structural material solution for energetic material warheads.

[0029] In this embodiment, the number of smeltings in step S300 is 2-3. By smelting the titanium ingot 2-3 times, the residual oxygen in the furnace chamber can be fully absorbed, oxygen impurities in the alloy melt can be reduced, and the adverse effects of oxygen on the material's reactivity and mechanical properties can be avoided. Controlling the number of smeltings within a reasonable range can ensure deoxidation while avoiding excessive consumption of the titanium ingot or molten pool contamination due to over-smelting. Compared with a multiple (e.g., 5 or more) smelting deoxidation process, 2-3 smeltings can ensure deoxidation while shortening the smelting time, improving production efficiency, and reducing energy consumption. This makes it suitable for industrial production and avoids increased production costs due to excessive smeltings. Excessive smeltings may cause the titanium ingot to over-melt and mix into the alloy melt, affecting the final composition ratio. 2-3 smeltings can precisely control the titanium ingot's oxygen absorption, preventing additional elements from interfering with the alloy ratio, and ensuring the accuracy and consistency of the composition during subsequent main alloy smelting. While one smelting may not completely remove residual oxygen, three smeltings can achieve sufficient deoxidation while avoiding molten pool temperature fluctuations or uneven alloy composition due to excessive smeltings. 2-3 smelting takes into account both deoxidation effect and process economy, and is suitable for the preparation needs of high-performance active medium-entropy alloys. While ensuring the low oxygen content of the alloy, it optimizes the process efficiency, making the material have both high purity and good controllability.

[0030] In this embodiment, the number of remelting cycles for each alloy in step S400 is 3-5. This allows the alloy melt to undergo multiple melting-solidification cycles, promoting thorough mixing of elements such as titanium, zirconium, and nickel, eliminating microsegregation, and improving compositional uniformity, thereby ensuring the alloy's mechanical properties and energy release stability. Remelting fewer than 3 times may result in inadequate mixing of components, affecting alloy properties. Remelting more than 5 times may lead to the inclusion of residual gases (such as H₂ and O₂) and low-melting-point impurities due to over-melting. Remelting 3-5 times ensures microstructure uniformity while avoiding energy waste. Remelting 3-5 times results in a more uniform grain size and phase distribution, improving strength (facilitating penetration). This range of remelting times maintains performance while balancing production efficiency and avoiding the cost increase associated with excessive remelting, making it suitable for large-scale production. Remelting 3-5 times achieves an optimal balance between compositional uniformity, purity, and overall performance, making it a key process parameter for preparing high-performance zirconium-titanium-nickel active medium-entropy alloys.

[0031] In this embodiment, the electromagnetic stirring in step S400 has a stirring current of 3A-8A, a single stirring time of 20S-50S, and is repeated 3-5 times. The electromagnetic stirring drives the molten liquid to generate forced convection to eliminate composition segregation, promote the discharge of residual oxygen in the molten liquid, and reduce the melting time. The electromagnetic stirring current of 3A-8A forms a controllable forced convection in the melt, effectively breaks the local enrichment of elements, promotes the uniform distribution of titanium, zirconium, and nickel, eliminates micro-segregation, and ensures the consistency of alloy composition. The molten liquid flow generated by electromagnetic stirring can accelerate the floating separation of bubbles and oxide inclusions. Combined with the stirring time of 20S-50S, the residual oxygen in the molten pool is fully discharged, and the oxygen content of the alloy is reduced. Repeating the intermittent stirring 3-5 times can avoid the temperature fluctuations caused by continuous stirring, and at the same time, through periodic convection, the grain size is refined, the porosity and shrinkage are reduced, the density of the alloy is improved, and the penetration ability and energy release stability are enhanced. The forced convection of electromagnetic stirring significantly accelerates the mixing speed of the melt, compared with the traditional melting which relies solely on diffusion, the melting time can be shortened, the energy consumption can be reduced, and the production efficiency can be improved. The current is limited to 3A-8A, and the single stirring time is 20S-50S, which can ensure the stirring intensity and prevent the molten liquid from splashing, element burning or temperature out of control caused by excessive current or too long time, and ensure the process stability. The parameter range design takes into account the effect and operability, which is easy to accurately control in large-scale production, and ensures the consistency of the performance of different batches of alloys. The electromagnetic stirring scheme balances the composition uniformity, impurity removal, structure optimization and energy efficiency ratio through precise current, time and frequency control, and provides process support for preparing high-performance zirconium-titanium-nickel active medium entropy alloy.

[0032] In this embodiment, the suction casting in step S500 uses a square copper mold with dimensions of 10mm x 10mm x 65mm, a cooling water temperature of 22°C, and the copper mold cavity is pre-evacuated to a high vacuum state before suction casting. The size of the copper mold and the water cooling temperature can ensure that the alloy cools to room temperature at a moderate rate. Neither the alloy produces amorphous structure due to too fast cooling speed, nor the alloy martensitic transformation is insufficient due to too slow cooling speed. By pre-evacuating the copper mold cavity to a high vacuum state, impurities such as O and N can be avoided during the suction casting process. The alloy ingot obtained by suction casting has a relatively sufficient martensitic transformation, a relatively large solid solubility of elements such as Ti and Ni in the matrix phase, and a high density of dislocations inside, thereby improving the resistance of the matrix phase to dislocation movement and improving the mechanical properties of the alloy.

[0033] In this embodiment, a pretreatment step S101 is added after step S100, that is, the raw materials are cleaned by ultrasonic alcohol and dried. Through ultrasonic alcohol cleaning, the grease, oxides and adsorbed impurities (such as dust and processing residues) on the surface of the granular pure titanium, zirconium and nickel can be effectively removed, so as to avoid the impurities from mixing into the alloy in the smelting process, reduce the content of harmful elements such as oxygen and carbon, and improve the material reactivity and mechanical properties. After the surface of the raw material is cleaned, bubbles or inclusions are not easy to be generated in the smelting process, the molten pool disturbance and spatter phenomenon are reduced, the electric arc smelting process is more stable, and the alloy composition is more controllable. The clean metal surface can promote the diffusion and combination of titanium, zirconium and nickel elements in the molten state, avoid composition segregation or local unmelted defects caused by pollutants, and improve the homogeneity of the alloy. After pretreatment, the raw materials are more easily and quickly melted, the energy and time required for smelting are reduced, the pollution of the furnace cavity caused by the volatilization of impurities is reduced, and the service life of the equipment is prolonged. Through the standardized cleaning and drying process, the initial state of different batches of raw materials is ensured to be consistent, thereby reducing the performance fluctuation and meeting the quality stability requirements of industrial production.

[0034] In this embodiment, the raw materials in step S100 are laboratory-grade pure zirconium, pure titanium and pure nickel, and the purity of the pure zirconium, pure titanium and pure nickel is 99.9%. The high purity of 99.9% ensures the accurate realization of the ternary ratio of titanium / zirconium / nickel, avoids the interference of impurity elements with the preset active medium entropy alloy composition system, and makes the final material performance strictly meet the design expectation; the low impurity content (<0.01%) can maximize the reactivity of the active metal (Zr, Ti), realize more sufficient and rapid chemical energy release in the warhead application, and enhance the secondary effect; the high-purity raw material has more consistent melting characteristics, which can avoid problems such as molten pool spatter and composition fluctuation caused by impurity gasification in the smelting process, and improve the repeatability and reliability of the electric arc smelting process; the ultra-low oxygen / nitrogen content effectively prevents the generation of brittle intermetallic compounds, so that the alloy has high density and good plasticity, and meets the penetration-energy release dual requirements; the use of laboratory-grade standard raw materials can provide a performance reference for subsequent industrial production, and exclude the interference factors of raw material purity in the research of material composition-process-performance relationship; although the purity requirement increases the cost of raw materials, it can avoid the complexity of subsequent impurity removal process, thereby reducing the overall production cost, and providing performance guarantee for industrial application of materials.

[0035] In this embodiment, the vacuum in step S200 is extracted to 5×10 -3 Pa or below. The vacuum degree of the furnace cavity is controlled at 5×10 -3Pa level, so that the oxygen partial pressure of the smelting environment is lower than the critical oxidation threshold of zirconium / titanium, fundamentally avoiding the oxidation reaction of active metals and ensuring the intrinsic activity of the alloy; this vacuum level can control the total content of interstitial elements (O, N, H) in the alloy to below 500ppm, preventing the formation of brittle oxide / nitride phases and ensuring the material obtains optimal ductility and energy release efficiency; the high vacuum environment promotes the desorption and escape of gas inclusions in the melt, thereby increasing the density of the alloy, reducing the porosity, and significantly improving the structural integrity under dynamic load; below 5×10 -3 The vacuum degree of Pa can maintain the plasma stability of arc discharge, reduce the arc drift caused by residual gas ionization, and control the melting current fluctuation range within ±2A; this vacuum standard provides a consistent initial environment for different batches of alloys, controls the dispersion of material properties within ±3%, and meets the strict requirements of industrial products for batch consistency; although maintaining this vacuum level requires increased equipment energy consumption, compared with subsequent remedial processes such as vacuum electron beam remelting, the overall cost is reduced and the yield rate is improved.

[0036] In this embodiment, the shielding gas introduced in step S200 is argon at a pressure of 0.05 MPa. This 0.05 MPa partial pressure of argon forms a dynamic equilibrium protective layer, effectively isolating air back-infiltration while preventing arc instability caused by excessive pressure, thereby achieving a dual protection mechanism of "vacuum melting + inert gas shielding." This reduces the volatilization rate of zirconium (boiling point 4377°C) and titanium (boiling point 3287°C), ensuring that the alloy composition strictly complies with the designed ratio, particularly guaranteeing the stability of the key active element zirconium. The 0.05 MPa argon plasma enhances the arc constriction effect, increasing the surface temperature gradient of the molten pool by approximately 15%, promoting the forced convection effect of electromagnetic stirring, and further eliminating microsegregation. Compared to conventional 0.1 MPa argon shielding, this reduces gas consumption, lowering gas costs per furnace, while also avoiding the risk of melt splashing caused by high-pressure environments.

[0037] The low-melting-point, high-energy-release zirconium-titanium-nickel active medium-entropy alloy of this embodiment is prepared by the above-mentioned method for preparing the low-melting-point, high-energy-release zirconium-titanium-nickel active medium-entropy alloy.

[0038] In this embodiment, the alloy is composed of the following elements, measured in atomic percentage: 25%-75% zirconium, 5%-45% titanium, 10.5%-30% nickel, and the remainder being unavoidable impurities. The protective composition range contains a relatively high TiZrNi ternary eutectic point; the eutectic composition can significantly lower the melting point of the ternary alloy, improve casting performance, and facilitate the molding of large parts; the addition of Ni introduces an intermetallic compound phase into the system, which improves the overall strength and plasticity of the alloy through the synergistic effect of the hard and brittle phase and the matrix phase; Ti / Zr are both active elements and can undergo a violent oxidation reaction to release energy under impact; a certain amount of intermetallic compound phase in the alloy can cause the alloy to form more small-sized fragments under high-speed loading, thereby improving the oxidation energy release efficiency.

[0039] In practice, a ZrTiNi active medium-entropy alloy with a low melting point and high energy release is provided, along with a preparation method. The alloy's chemical composition is: 25-75 atomic percent zirconium, 5-45 atomic percent titanium, and 10.5-30 atomic percent nickel, with the remainder being unavoidable impurities. Designed around the zirconium-nickel-titanium ternary eutectic system, the resulting alloy exhibits a low melting point (below 1200°C), high strength (compressive strength approaching 1500 MPa), high energy release (theoretical heat of combustion up to 11.96 kJ / g), and sufficient plasticity (fracture deformation rate up to 21.6%). The ZrTiNi alloy is prepared by vacuum non-consumable electrode arc melting, with each ingot melted 3-5 times with electromagnetic stirring to ensure uniform composition. The alloy ingots are then obtained by suction casting, with rapid cooling promoting martensitic transformation and improving the alloy's mechanical properties. Comprehensive analysis indicates that the alloy exhibits excellent mechanical properties, outstanding energy release, and good processability, demonstrating its potential for large-scale industrial production and engineering applications. This solves or partially solves the problem of mismatch between alloy energy release characteristics, mechanical properties and processability in the prior art.

[0040] A method for preparing a zirconium-titanium-nickel active medium-entropy alloy with a low melting point and high energy release is provided. The raw materials are ultrasonically cleaned and dried with alcohol, and then placed in a vacuum non-consumable electrode melting furnace for melting. The vacuum degree is 5×10 -3Pa, before smelting the alloy, first smelt the titanium ingot in the center of the furnace cavity to absorb residual oxygen, after the tungsten electrode is ignited, the smelting current is kept at 190A-220A, and electromagnetic stirring is assisted, the smelting time is 3 min each time to avoid long-time smelting of the alloy to absorb oxygen and hydrogen, and the alloy is smelted 3-5 times each to ensure uniform composition. The alloy ingot is obtained by suction casting, the alloy melt is rapidly cooled by means of a square water-cooled copper mold with a size of 10mmx10mmx65mm, the water cooling temperature is 22℃, the alloy martensite phase change is promoted, and the mechanical properties of the alloy are improved. Alternatively, the titanium ingot is first smelted 1-2 times in the center of the furnace before smelting the alloy, which further absorbs the residual oxygen in the cavity on the basis of high vacuum in the furnace cavity. Alternatively, electromagnetic stirring is assisted during single smelting of the alloy, the stirring current is 5A, the single time is about 30s, and the process is repeated 3-5 times, the electromagnetic force is used to drive the forced convection of the melt to eliminate composition segregation and promote the discharge of residual oxygen in the melt, and the smelting time can be reduced.

[0041] More specifically, the preparation method of the zirconium-nickel-titanium alloy comprises the following steps:

[0042] (1) Pretreatment: the raw materials are ultrasonically cleaned with alcohol for 15 min and dried;

[0043] (2) Smelting and suction casting: the raw materials are placed in a vacuum non-consumable electrode smelting furnace for smelting, the vacuum degree is 5x10 -3 Pa, before smelting the alloy, first smelt the titanium ingot in the center of the furnace cavity to absorb residual oxygen, reduce the oxygen content in the furnace cavity; after the tungsten electrode is ignited, the smelting current is kept at 190-220A, and electromagnetic stirring is assisted during the process. The electromagnetic stirring current is 5A to avoid splashing of the melt caused by too large current; under the condition that the melt flows well, the stirring is repeated 3-5 times for each smelting, the single time is about 30s, the electromagnetic force is used to drive the forced convection of the melt to eliminate composition segregation and promote the discharge of residual oxygen in the melt, at the same time, the smelting time is reduced, energy is saved, and a large amount of oxygen and hydrogen is avoided to be absorbed by the alloy during long-time smelting. The smelting time of the alloy is 3 min each time, and the alloy is smelted 5 times each to ensure uniform composition. The alloy ingot is obtained by suction casting, the alloy melt is rapidly cooled by means of a square water-cooled copper mold with a size of 10mmx10mmx65mm, the water cooling temperature is 22℃, the alloy martensite phase change is promoted, and the mechanical properties of the alloy are improved.

[0044] The alloy has the following advantages:

[0045] (1) The alloy has a relatively low melting point and good fluidity, and is suitable for industrial smelting and large-scale casting;

[0046] (2) The alloy prepared has a low melting point (below 1200℃), high strength (compressive strength close to 1500MPa), high energy release (theoretical combustion heat can reach 11.96kJ / g), and sufficient plasticity (fracture deformation rate can reach 21.6%). Compared with other metal-type energetic structural materials, it has the advantage of balanced energy release characteristics, mechanical properties and processability.

[0047] Example 1:

[0048] The present invention provides a method for preparing a zirconium-nickel-titanium active medium-entropy alloy with a low melting point and high energy release, comprising the following steps:

[0049] S1. Weigh 3.86 g of pure titanium (99.9%) granules, 40.69 g of pure zirconium (99.9%) granules, and 5.45 g of pure nickel (99.9%) granules, respectively, with atomic percentages of Ti 13%, Zr 72%, and Ni 15%, and then ultrasonically clean the metal granules in ethanol for 15 minutes and set aside.

[0050] S2, place the zirconium, titanium and nickel particles in S1 in a non-consumable vacuum arc melting furnace and evacuate to 5×10 -3 Below Pa;

[0051] S3, introducing 0.05MPa argon gas into the vacuum arc melting furnace;

[0052] S4, first smelting the titanium ingot located in the center of the furnace chamber three times to further absorb the residual oxygen in the furnace chamber;

[0053] S5. Melting zirconium-nickel-titanium alloy; wherein, the melting number is 6 times, each melting time is 3 minutes, and the melting current is 200A; during a single melting process, electromagnetic stirring is performed 3 times, each time for about 30 seconds, and the stirring current is 5A, to promote the flow of the melt, eliminate component segregation, discharge residual oxygen, and reduce the melting time;

[0054] S6. Suction casting: The copper mold cavity is pre-evacuated to a high vacuum state. The copper mold dimensions are 10 mm × 10 mm × 65 mm. The cooling water temperature is 22°C. Rapid cooling of the copper mold promotes the martensitic transformation of the alloy and improves its mechanical properties.

[0055] Example 2:

[0056] The present invention provides a method for preparing a zirconium-nickel-titanium active medium-entropy alloy with a low melting point and high energy release, comprising the following steps:

[0057] S1. Weigh 2.36 g of pure titanium (99.9%) granules, 40.42 g of pure zirconium (99.9%) granules, and 7.22 g of pure nickel (99.9%) granules, respectively, with atomic percentages of Ti 8%, Zr 72%, and Ni 20%, and then ultrasonically clean the metal granules in ethanol for 15 minutes and set aside.

[0058] S2, place the zirconium, titanium and nickel particles in S1 in a non-consumable vacuum arc melting furnace and evacuate to 5×10 -3 Below Pa;

[0059] S3, introducing 0.05MPa argon gas into the vacuum arc melting furnace;

[0060] S4, firstly, smelting the titanium ingot located in the center of the furnace chamber three times;

[0061] S5. Melting zirconium-nickel-titanium alloy; wherein the melting times are 6 times, each melting time is 3 minutes, and the melting current is 200A; electromagnetic stirring is used during the melting process;

[0062] S6. Suction casting: The copper mold cavity is pre-evacuated to a high vacuum state. The copper mold dimensions are 10 mm × 10 mm × 65 mm. The cooling water temperature is 22°C. Rapid cooling of the copper mold promotes the martensitic transformation of the alloy and improves its mechanical properties.

[0063] Example 3:

[0064] The present invention provides a method for preparing a zirconium-nickel-titanium active medium-entropy alloy with a low melting point and high energy release, comprising the following steps:

[0065] S1. Weigh 3.03 g of pure titanium (99.9%), 38.07 g of pure zirconium (99.9%), and 8.91 g of pure nickel (99.9%) particles, respectively, with atomic percentages of Ti 10%, Zr 66%, and Ni 24%. Then, ultrasonically clean the metal particles in ethanol for 15 minutes and set aside.

[0066] S2, place the zirconium, titanium and nickel particles in S1 in a non-consumable vacuum arc melting furnace and evacuate to 5×10 -3 Below Pa;

[0067] S3, introducing 0.05MPa argon gas into the vacuum arc melting furnace;

[0068] S4, firstly, smelting the titanium ingot located in the center of the furnace chamber three times;

[0069] S5. Melting zirconium-nickel-titanium alloy; wherein the melting times are 6 times, each melting time is 3 minutes, and the melting current is 200A; electromagnetic stirring is used during the melting process;

[0070] S6. Suction casting: The copper mold cavity is pre-evacuated to a high vacuum state. The copper mold dimensions are 10 mm × 10 mm × 65 mm. The cooling water temperature is 22°C. Rapid cooling of the copper mold promotes the martensitic transformation of the alloy and improves its mechanical properties.

[0071] Example 4:

[0072] The present invention provides a method for preparing a zirconium-nickel-titanium active medium-entropy alloy with a low melting point and high energy release, comprising the following steps:

[0073] S1. Weigh 3.73 g of pure titanium (99.9%), 35.58 g of pure zirconium (99.9%), and 10.68 g of pure nickel (99.9%) particles, respectively, with the atomic percentages of Ti 12%, Zr 60%, and Ni 28%, and then ultrasonically clean the metal particles in ethanol for 15 minutes and set aside.

[0074] S2, place the zirconium, titanium and nickel particles in S1 in a non-consumable vacuum arc melting furnace and evacuate to 5×10 -3 Below Pa;

[0075] S3, introducing 0.05MPa argon gas into the vacuum arc melting furnace;

[0076] S4, firstly, smelting the titanium ingot located in the center of the furnace chamber three times;

[0077] S5. Melting zirconium-nickel-titanium alloy; wherein the melting times are 6 times, each melting time is 3 minutes, and the melting current is 200A; electromagnetic stirring is used during the melting process;

[0078] S6. Suction casting: The copper mold cavity is pre-evacuated to a high vacuum state. The copper mold dimensions are 10 mm × 10 mm × 65 mm. The cooling water temperature is 22°C. Rapid cooling of the copper mold promotes the martensitic transformation of the alloy and improves its mechanical properties.

[0079] Performance testing:

[0080] The X-ray diffraction (XRD) test patterns of the alloys prepared in Examples 1-4 are shown in FIG. Figure 1 shown.

[0081] from Figure 1 It can be seen that the phase composition of the prepared alloy includes α-phase, β-phase, and NiZr2 phase. The α-phase and β-phase are solid solution phases, while the NiZr2 phase is an intermetallic compound phase. In the examples presented, their content is primarily constrained by the nickel content. It can be seen that as the nickel content decreases, the diffraction peak intensity of the alloy α- and β-phases increases, while the diffraction peak intensity of the NiZr2 phase decreases.

[0082] Table 1 Mechanical properties of alloys prepared in different embodiments

[0083]

[0084] from Figure 2 The differential scanning calorimetry (DSC) test graphs shown show melting endothermic peaks between 700°C and 1000°C, indicating a low melting point. Notably, the melting peaks of the four compositions between 884°C and 933°C shift toward higher temperatures and expand in area for the three compositions in Examples 1-3 as the Ni content increases. This is because the temperature range of the solid-liquid coexistence zone shrinks with increasing Ni content, allowing the alloy to absorb more heat within a narrower temperature range to melt. In contrast, Example 4 exhibits a sharp endothermic peak at 807°C and a smaller endothermic peak at 933°C, indicating that the alloy has essentially completed its melting process through a eutectic reaction, resulting in better castability. Comparative analysis indicates that the alloy's castability decreases with decreasing Ni content.

[0085] Matters not covered by the present invention are known technologies.

[0086] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0087] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that variations and improvements are possible without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

[0088] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a zirconium-titanium-nickel active medium-entropy alloy with a low melting point and high energy release, characterized in that: The following steps are involved: S100, preparing raw materials, and weighing granular pure titanium, granular pure zirconium, and granular pure nickel according to preset atomic percentages; In atomic percentage, it is composed of the following elements: 25%-75% zirconium, 5%-45% titanium, 10.5%-30% nickel, and the balance is unavoidable impurities; S200, placing the raw materials in a non-consumable vacuum arc melting furnace, separating them from the preset titanium ingots in the furnace chamber, evacuating the furnace, and introducing a protective gas; S300, melting the preset titanium ingot in the center of the furnace chamber to absorb residual oxygen, the melting times are 1 to 5 times; S400, after arc striking, maintaining the melting current at 190A-220A, and supplemented by electromagnetic stirring, melting the mixture of granular pure titanium, granular pure zirconium and granular pure nickel, and melting to form zirconium-nickel-titanium alloy, and performing multiple melting of the formed zirconium-nickel-titanium alloy, each melting time being controlled within 2min-4min, and each alloy being melted 4-8 times; S500, the melt is rapidly cooled in a square water-cooled copper mold by suction casting to obtain a zirconium-titanium-nickel active medium-entropy alloy with a low melting point and high energy release.

2. The method for preparing a low melting point, high energy release zirconium-titanium-nickel active medium entropy alloy according to claim 1, characterized in that: The number of smelting times in step S300 is 2 to 3 times.

3. The method for preparing a low melting point, high energy release zirconium-titanium-nickel active medium entropy alloy according to claim 1, characterized in that: In step S400 , each alloy is melted 3 to 5 times.

4. The method for preparing a low melting point, high energy release zirconium-titanium-nickel active medium entropy alloy according to claim 1, characterized in that: The electromagnetic stirring in step S400 has a stirring current of 3A-8A and a single stirring time of 20S-50S, which is repeated 3-5 times. Electromagnetic force is used to drive the melt to produce forced convection to eliminate component segregation, promote the discharge of residual oxygen in the melt, and reduce the smelting time.

5. The method for preparing a low melting point, high energy release zirconium-titanium-nickel active medium entropy alloy according to any one of claims 1 to 4, characterized in that: After step S100, a pre-treatment step S101 is added to clean the raw materials using alcohol ultrasonic cleaning and drying.

6. The method for preparing a low melting point, high energy release zirconium-titanium-nickel active medium entropy alloy according to any one of claims 1 to 4, characterized in that: The raw materials in step S100 are laboratory-grade pure zirconium, pure titanium and pure nickel, and the purity of pure zirconium, pure titanium and pure nickel are all 99.9%.

7. The method for preparing a low melting point, high energy release zirconium-titanium-nickel active medium entropy alloy according to any one of claims 1 to 4, characterized in that: In step S200, the vacuum is pumped to 5×10 -3 Below Pa.

8. The method for preparing a low melting point, high energy release zirconium-titanium-nickel active medium entropy alloy according to any one of claims 1 to 4, characterized in that: The protective gas introduced in step S200 is argon gas at 0.05 MPa.

9. A zirconium-titanium-nickel active medium-entropy alloy with low melting point and high energy release, characterized in that: The alloy is prepared by the method for preparing a zirconium-titanium-nickel active medium-entropy alloy with a low melting point and high energy release according to any one of claims 1 to 8.

10. The low melting point and high energy release zirconium-titanium-nickel active medium entropy alloy according to claim 9, characterized in that: Calculated by atomic percentage, it is composed of the following elements: 25%-75% zirconium, 5%-45% titanium, 10.5%-30% nickel, and the remainder is unavoidable impurities.

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