An Al / Zr / Bi2O3 ternary energetic structural material, its preparation method and application

Abstract

This application relates to an Al / Zr / Bi2O3 energetic structural material, its preparation method, and its applications, belonging to the field of energetic materials technology. In the Al / Zr / Bi2O3 energetic structural material of this application, the atomic ratio of Al to Zr is (1.3-3):1, and the mass fraction of Bi2O3 is 1-7 wt.%. This invention effectively reduces the reaction initiation threshold and improves the overall energy release efficiency by introducing Bi2O3 oxidant into the Al-Zr energetic system, solving the technical problem that existing energetic structural materials cannot simultaneously achieve both mechanical strength and efficient impact energy release performance.

Description

Technical Field

[0001] This invention belongs to the technical field of energetic materials and metal matrix composite materials, specifically relating to an Al / Zr / Bi2O3 ternary energetic structural material, its preparation method, and its application. Background Technology

[0002] With the ever-increasing demands on the effectiveness of destructive components in modern warfare, traditional single-mode destruction relying on kinetic energy penetration or explosive fragmentation is no longer sufficient to meet the operational needs of complex battlefield environments. Energetic structural materials (also known as reactive materials), as a novel type of intelligent material, can not only maintain structural integrity to achieve penetration under high-speed impact loading, but also trigger a violent chemical reaction upon fragmentation, releasing a large amount of chemical energy, thus forming an enhanced destruction effect through the coupling of kinetic and chemical energy. This type of material shows broad application prospects in advanced destructive components such as reactive fragments and reactive propellant shrouds.

[0003] Currently, research on energetic structural materials mainly focuses on two major systems: one is the metal / polymer system (such as Al / PTFE), which has high energy release efficiency but low mechanical strength, making it difficult to adapt to high overload emission environments; the other is the metal / metal system (such as Al-Ni, Al-Zr, Al-Fe, etc.), which releases energy through chemical reactions between components and has a certain structural strength, but often suffers from high reaction initiation thresholds and insufficient energy release. The Al-Zr binary system, in particular, while possessing a high theoretical heat of reaction, requires high temperatures and long diffusion times for its solid-state reaction, making it difficult to be effectively activated at the moment of impact, thus limiting chemical energy release efficiency. Therefore, existing technologies lack a solution to resolve the contradiction between the "mechanical strength" and "impact energy release" performance of metal-based energetic structural materials and to achieve optimization through specific composition and process design. How to effectively reduce the impact reaction initiation threshold and improve energy release efficiency while ensuring good mechanical properties of the material has become a core technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0004] To address the shortcomings of existing energetic structural materials in achieving both high mechanical strength and high impact energy release efficiency, this application provides an Al / Zr / Bi2O3 ternary energetic structural material, which, through component optimization design, can preferentially trigger redox reactions under impact loading, thereby promoting rapid reactions in the main system, as well as its preparation method and applications.

[0005] The technical solution of this invention is: The first aspect of this application provides an Al / Zr / Bi2O3 ternary energetic structure material, the material being composed of Al, Zr and Bi2O3 components, wherein the atomic ratio of Al to Zr is (1.3-3):1, and the mass fraction of Bi2O3 is 1-7 wt.%.

[0006] As a preferred embodiment of the Al / Zr / Bi2O3 ternary energetic structural material of the present invention, the particle size of the Al powder is 20-30 μm, the particle size of the Zr powder is 10-20 μm, and the particle size of the Bi2O3 powder is 100 nm.

[0007] As a preferred embodiment of the Al / Zr / Bi2O3 ternary energetic structural material of the present invention, the material is a dense bulk material prepared by ball milling and rotary forging processes. Its phase composition includes Al, Zr and Bi2O3, and no intermetallic compounds are formed, which ensures the structural stability of the material during the forming process and the integrity of subsequent reactions.

[0008] The second aspect of this application provides a method for preparing an Al / Zr / Bi2O3 ternary energetic structural material, comprising the following steps: S1. Ball milling and powder mixing: Weigh Al powder, Zr powder and Bi2O3 powder according to the proportion, place them in a ball mill jar, and ball mill them under an inert atmosphere to obtain energetic composite powder. S2. Rotary forging: The energetic composite powder obtained in step S1 is vacuum-sealed in a carbon steel tube and then subjected to multiple continuous plastic deformation processes in a rotary forging machine. The powder is densified under the combined action of radial compression and axial extension to obtain a block energetic structural material with uniform structure. The rotary forging speed is 10~15 mm / s and the deformation is 40-50%.

[0009] As a preferred embodiment of the preparation method described in this invention, in step S1, analytical grade n-hexane is used as the process control agent during the ball milling process, the ball milling speed is 200-400 r / min, the ball-to-material ratio is (8-10):1, and the ball milling time is 1-5 hours.

[0010] As a preferred embodiment of the preparation method described in this invention, the extrusion speed of the rotary forging process in step S2 is 5-20 mm / s.

[0011] As a preferred embodiment of the preparation method described in this invention, the block material obtained after rotary forging in step S2 is a round bar with a diameter of 10 mm.

[0012] According to the preparation method of claim 4, the ball milling in step S1 is intermittent ball milling, with a 1-minute pause after every 9 minutes of ball milling.

[0013] A third aspect of this application provides the application of an Al / Zr / Bi2O3 ternary energetic structural material in damage warhead components, particularly in reactive fragments or active charge shrouds.

[0014] Advantages and beneficial effects of the present invention: (1) The Al / Zr / Bi2O3 ternary energetic structural material combines the Al / Zr binary system with Bi2O3 oxidant. While meeting the mechanical requirements of a structural material, the introduction of Bi2O3 provides a key initial heat source through a redox reaction preferential initiation mechanism, which greatly improves the impact sensitivity. In addition, compared with conventional oxidants, Bi2O3 has a significantly lower melting point (about 825℃), which is significantly lower than typical oxidants such as Fe2O3 (about 1565℃) and CuO (about 1330℃). Under impact load, the local temperature rise inside the material can quickly soften or even melt Bi2O3, thereby forming a transient liquid phase at the particle interface, changing the reaction from a traditional solid-phase diffusion process to a liquid-phase participation process, thus lowering the reaction initiation threshold.

[0015] (2) The introduction of Bi2O3 not only provides additional heat of reaction, but its reaction products (such as active Bi element) may also participate in subsequent reactions, further promoting the energy release of the Al-Zr system. Ballistic gun penetration tests show that the energy release of Al / Zr / Bi2O3 material can reach 4.70 to 7.07 kJ / g, which is much higher than the 2.24 kJ / g of the pure Al / Zr system.

[0016] (3) The present invention adopts a process route of ball milling and powder mixing combined with rotary forging, which can obtain bulk materials with uniform structure and high density. XRD analysis shows that no brittle intermetallic compounds are generated during the forming process, which ensures the mechanical load-bearing capacity of the material as a structural element. Both ball milling and rotary forging are mature metal processing technologies with controllable costs, suitable for preparing parts with complex shapes, and have good prospects for engineering applications. Attached Figure Description

[0017] Figure 1 X-ray diffraction patterns of Al / Zr and Al / Zr / Bi2O3 energetic structural materials in Comparative Example 1 and Examples 1-4; Figure 2 Scanning electron microscope (SEM) images of the Al / Zr / Bi2O3 energetic structural materials in Examples 1-4; Figure 3 The pressure-velocity relationship fitting graphs for Al / Zr and Al / Zr-3%Bi2O3 in Comparative Example 1 and Example 3 are shown. Detailed Implementation

[0018] To better illustrate the purpose, technical solution, and advantages of this application, the following detailed description, in conjunction with specific embodiments, aims to explain the content of this application in detail, rather than to limit it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application.

[0019] Example 1 This embodiment describes an Al / Zr-1% Bi2O3 ternary energetic structural material, with an Al / Zr atomic percentage of 1.3:1 and a Bi2O3 content of 1 wt.%.

[0020] A method for preparing an Al / Zr-1% Bi2O3 ternary energetic structural material includes the following steps: Step 1) Ingredients: Al, Zr, and Bi2O3 powders with a purity of not less than 99.9% (particle size 100 nm) are used as raw materials, and the ingredients are prepared by converting atomic percentages to mass percentages. Step 2) Ball milling: Place the accurately weighed raw material from step 1) into a vacuum ball mill jar, use analytical grade n-hexane as the process control agent, fill the jar with argon as a protective gas, place it in a planetary ball mill, and ball mill at 300 r / min for 1 hour under argon protection, stopping for 1 minute every 9 minutes of ball milling.

[0021] Step 3) Rotary forging: The energetic powder prepared by ball milling is loaded into a carbon steel pipe and extruded at a speed of 5-20 mm / s to obtain a round bar with a diameter of 10 mm.

[0022] Example 2 This embodiment describes an Al / Zr-3 wt.% Bi2O3 ternary energetic structural material, in which the atomic ratio of Al to Zr is 1.3:1 and the mass fraction of Bi2O3 is 3 wt.%. Its preparation method is the same as in Example 1.

[0023] Example 3 This embodiment presents an Al / Zr-5 wt.% Bi2O3 ternary energetic structural material, wherein the atomic ratio of Al to Zr is 1.3:1, and the mass fraction of Bi2O3 is 5 wt.%. Its preparation method is the same as in Example 1.

[0024] Example 4 This embodiment describes an Al / Zr-7 wt.%Bi2O3 ternary energetic structural material, in which the atomic ratio of Al to Zr is 1.3:1 and the mass fraction of Bi2O3 is 7 wt.%. Its preparation method is the same as in Example 1.

[0025] Example 5 This embodiment describes an Al / Zr-1 wt.%Bi2O3 ternary energetic structural material, in which the atomic ratio of Al to Zr is 3:1 and the mass fraction of Bi2O3 is 1 wt.%. Its preparation method is the same as in Example 1.

[0026] Comparative Example 1 This comparative example presents an Al / Zr binary energetic structural material with an Al to Zr atomic ratio of 1.3:1. Its preparation method is the same as in Example 1, except that Bi₂O₃ powder is not added.

[0027] Performance testing 1) XRD and SEM testing The Al / Zr / Bi2O3 materials from Examples 1 to 4 and the Al / Zr energetic structural material from Comparative Example 1 were subjected to XRD and SEM tests. The test results are as follows: Figure 1 , Figure 2 .

[0028] according to Figure 1 It can be seen that the phases of the Al / Zr / Bi2O3 rotary forging samples with each ratio are composed of Al, Zr and Bi2O3. No diffraction peaks of intermetallic compounds were observed, indicating that no obvious solid-phase reaction or phase transformation occurred inside the material under the rotary forging process conditions. Figure 2 (ad)SEM sequentially shows that after rotary forging, Al / Zr / Bi2O3 samples with Bi2O3 content of 1, 3, 5, and 7 wt.% exhibit a continuous ductile metal matrix composed of Al phase, a uniformly embedded equiaxed Zr phase in Al phase, and a Bi2O3 phase mainly enriched along the particle boundaries.

[0029] 2) Ballistic gun penetration test The Al / Zr / Bi2O3 materials from Examples 1 to 4 and the Al / Zr energetic structural material from Comparative Example 1 were subjected to ballistic gun penetration tests. To quantitatively evaluate the chemical energy release characteristics of the Al / Zr / Bi2O3 energetic structural material after ballistic penetration triggering in this study, the Vented Chamber Calorimetry (VCC) method was used for calculation. The total energy includes two parts: chemical energy and kinetic energy. The contribution of the kinetic energy of the fragments to the quasi-static pressure was removed. The results are shown in Table 1.

[0030] Table 1. Test results of ballistic gun penetration test Example 1 <![CDATA[Al / Zr-1%. Bi2O3]]> 0.801 4.70 Example 2 <![CDATA[Al / Zr-3%. Bi2O3]]> 0.796 6.26 Example 3 <![CDATA[Al / Zr-5%. Bi2O3]]> 0.79 7.07 Example 4 <![CDATA[Al / Zr-7%. Bi2O3]]> 0.799 5.36 Comparative Example 1 Al / Zr 0.8 2.24 According to the data in Table 1, under the same experimental conditions, the energy release of the Al / Zr / Bi2O3 energetic structural materials in Examples 1 to 4 ranged from 4.70 to 7.07 kJ / g, which was much higher than that of Comparative Example 1. Figure 3The data shows that the velocity threshold of Al / Zr (0.662 km / s) is significantly higher than that of Al / Zr-3% Bi2O3 (0.357 km / s), indicating that the introduction of Bi2O3 lowers the reaction initiation threshold, resulting in a stronger thermodynamic driving force for the redox reaction and a shorter interfacial reaction path. This makes it easier to activate the reaction after the formation of the impact-induced hotspot, thus providing a heat source earlier and promoting subsequent solid-phase diffusion / combination processes. On the other hand, the slope of Al / Zr-3% Bi2O3 (1.932) is higher than that of Al / Zr (1.557), suggesting that the introduction of Bi2O3 has a higher sensitivity to impact loading.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. An Al / Zr / Bi2O3 energetic structural material, characterized in that, The material is composed of Al, Zr and Bi2O3 components, wherein the atomic ratio of Al to Zr is (1.3-3):1, and the mass fraction of Bi2O3 is 1-7 wt.%.

2. The Al / Zr / Bi₂O₃ energetic structural material according to claim 1, characterized in that, The Al powder has a particle size of 20-30 μm, the Zr powder has a particle size of 10-20 μm, and the Bi2O3 powder has a particle size of 100 nm.

3. The Al / Zr / Bi₂O₃ energetic structural material according to claim 1, characterized in that, The material is a dense bulk material prepared by ball milling and rotary forging processes. Its phase composition includes Al, Zr and Bi2O3, and no intermetallic compounds are formed.

4. A method for preparing the Al / Zr / Bi2O3 ternary energetic structural material according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Ball milling and powder mixing: Weigh Al powder, Zr powder and Bi2O3 powder according to the proportion, place them in a ball mill jar, and ball mill them under an inert atmosphere to obtain energetic composite powder. S2. Rotary forging: The energetic composite powder obtained in step S1 is vacuum-encapsulated in a carbon steel tube and then rotary forged to obtain a dense bulk material.

5. The preparation method according to claim 4, characterized in that, In step S1, analytical grade n-hexane is used as the process control agent during the ball milling process. The ball milling speed is 200-400 r / min, the ball-to-material ratio is (8-10):1, and the ball milling time is 1-5 hours.

6. The preparation method according to claim 4, characterized in that, The extrusion speed of the rotary forging process in step S2 is 5-20 mm / s.

7. The preparation method according to claim 4, characterized in that, The block material obtained after rotary forging in step S2 is a round bar with a diameter of 10 mm.

8. The preparation method according to claim 4, characterized in that, The ball milling described in step S1 is an intermittent ball milling process, with a 1-minute pause after every 9 minutes of milling.

9. The application of the Al / Zr / Bi2O3 ternary energetic structural material according to any one of claims 1-3 in a destructive warhead element.

Images