A titanium-based lightweight multi-principal element alloy resistant to high-speed impact and its preparation method

Abstract

This invention belongs to the field of metallic materials technology, and relates to a titanium-based lightweight multi-principal element alloy resistant to high-speed impact and its preparation method. The key feature is that the titanium-based multi-principal element alloy is mainly composed of a BCC structural phase, with a BCC structural phase content of over 95% and an average grain size of less than 100 μm for the BCC phase; the density of the high-speed impact resistant titanium-based multi-principal element alloy is less than 5.1 g / cm³. 3 Under dynamic impact conditions, the strength reaches over 1600 MPa, and the critical strain rate for impact failure reaches 5000 s⁻¹. ‑1 The absorption energy reaches 650 J / cm³. 3 It has great application potential in the extreme high-speed impact structures required for new aerospace structural components.

Description

Technical Field

[0001] This invention belongs to the field of metallic materials technology and relates to a titanium-based lightweight multi-principal element alloy resistant to high-speed impact and its preparation method. Background Technology

[0002] Traditionally, iron-based alloys are used as structural materials for high-speed impact environments. However, in recent years, reports from Europe and the United States have indicated the use of titanium alloys in missile casings and bulletproof structures. This is primarily due to the low density and high specific strength of titanium alloys, along with their superior dynamic mechanical properties. Replacing traditional iron-based alloys can achieve significant structural weight reduction.

[0003] With the further advancement of high-end technology applications, existing titanium alloy materials can no longer meet the needs of use in extreme high-speed impact environments. Therefore, there is an urgent need for new lightweight high-speed impact resistant materials. Multi-principal element alloys are a new type of metallic structural material developed in the last decade or so. Refractory multi-principal element alloys such as Ti, Zr, Hf, Nb, and Ta have shown excellent resistance to dynamic impact. However, due to their high density, they are suitable as fragmentation materials but difficult to use as shell materials.

[0004] Titanium-based multi-principal-element alloys are a new type of titanium-based alloy produced by the design method of high-entropy alloys. They usually contain four or more elements from Ti, Al, Cr, Nb, V, Zr, Mo and Sn as main elements. The alloys have good room temperature strength and plasticity matching. After the alloy composition is refined, it is expected to obtain extreme environmental properties such as resistance to high-speed impact and oxidation. Summary of the Invention

[0005] The purpose of this invention is to address the urgent need for lightweight, high-speed impact-resistant materials in novel aerospace structural components by providing a low-density, quasi-static, high-strength, and well-ductile titanium-based lightweight multi-principal-element alloy with superior dynamic mechanical properties, as well as its preparation method.

[0006] To solve this technical problem, the technical solution of the present invention is as follows:

[0007] A high-speed impact-resistant titanium-based lightweight multi-principal element alloy is disclosed, wherein the titanium-based multi-principal element alloy is mainly composed of a BCC structural phase, with a BCC structural phase content of more than 95% and an average grain size of less than 100 μm for the BCC phase; the density of the high-speed impact-resistant titanium-based multi-principal element alloy is less than 5.1 g / cm³. 3 Under dynamic impact conditions, the strength reaches over 1600 MPa, and the critical strain rate for impact failure reaches 5000 s⁻¹. -1 The absorbed energy can reach 650 J / cm². 3The above-mentioned titanium-based multi-principal-element alloy has the following chemical composition in atomic percentage: Ti: 60%–75%, Al: 10%–20%, V+Fe+Mo+Cr+Nb+Zr: 11%–25%, with the balance being unavoidable impurities.

[0008] Preferably, the chemical composition of the titanium-based multi-principal-element alloy, in terms of atomic percentage, contains: V+Fe+Mo+Cr+Nb+Zr in the range of 12% to 22%, wherein at least two elements have a content of 5% or more.

[0009] Preferably, the chemical composition of the titanium-based multi-principal-element alloy contains, in atomic percentage, Al in the range of 10% to 16%.

[0010] Preferably, the chemical composition of the titanium-based multi-principal-element alloy contains, in atomic percentage, V in the range of 5% to 10%.

[0011] Preferably, the chemical composition of the titanium-based multi-principal-element alloy contains, in atomic percentage, Cr in the range of 5% to 7.8%.

[0012] Preferably, the chemical composition of the titanium-based multi-principal-element alloy contains Nb in the range of 5% to 9.8% by atomic percentage.

[0013] The preparation method of the titanium-based lightweight multi-principal element alloy resistant to high-speed impact specifically includes the following steps:

[0014] S1: Obtain alloy ingots by means of vacuum consumable melting, solidification melting, or a combination of consumable melting and solidification melting;

[0015] S2: The required billet, forging, or structural component is prepared by thermomechanical treatment methods such as forging, extrusion, and rolling.

[0016] Preferably, in the thermomechanical treatment method for the high-speed impact resistant titanium-based lightweight multi-principal-element alloy, the hot working temperature of the billet during the ingot casting stage is controlled at 1000℃~1150℃, the deformation per firing in the billet casting stage is controlled at more than 75%, and the deformation rate is 0.5s. -1 ~1.5s -1 After billet preparation, the average grain size is controlled below 200 μm; in the final forming stage, the hot working temperature of the billet is controlled between 800℃ and 900℃, the deformation is controlled above 95%, and the deformation rate is below 0.01 s. -1 ~0.1s -1 Annealing can be performed as needed to obtain alloy materials with an average grain size of less than 100μm.

[0017] Traditional titanium alloys typically have a predominantly β-phase opening process and a final forming stage in the α+β two-phase region, making microstructure refinement and homogenization relatively easy. However, unlike traditional titanium alloys, the titanium-based multi-principal element alloy described herein consists entirely of a single β-phase (BCC structure) below 1150℃, lacking an α-phase. The single β-phase exhibits a greater tendency for grain growth during hot working, making it difficult to achieve the grain refinement and homogenization of the titanium-based multi-principal element alloy as described in this invention using traditional manufacturing processes. Grain refinement and homogenization significantly impact high-speed impact resistance. Therefore, based on the hot deformation characteristics of the titanium-based multi-principal element alloy, this invention innovatively designs a thermomechanical treatment process that can achieve grain refinement and homogenization within its range.

[0018] Preferably, the oxygen content in the multi-principal alloy ingot is controlled to be below 0.07 wt.%.

[0019] The beneficial effects of this invention are:

[0020] (1) The titanium-based lightweight multi-principal element alloy provided by the present invention, through the comprehensive control of Ti, Al and other alloying elements, achieves good strength and plasticity matching under quasi-static conditions, with a strength-plasticity product of over 9000 MPa%; under dynamic impact conditions, the strength reaches over 1600 MPa, and the critical strain rate for impact failure reaches 5000 s. -1 The absorbed energy can reach 650 J / cm². 3 The critical strain rate of existing titanium alloys is only 3000 s⁻¹. -1 ~4000s -1 Within this range, the absorption energy is only 350–500 J / cm. 3 It is evident that the alloy provided by this invention exhibits significantly higher dynamic mechanical properties than existing titanium alloy materials. It is a lightweight structural material with low density, high strength under quasi-static conditions, good plasticity, and ultra-high dynamic mechanical properties. It can overcome the limitations of traditional titanium alloys in dynamic mechanical properties and has the potential for use in more extreme high-speed impact environments.

[0021] (2) The titanium-based lightweight multi-principal element alloy resistant to high-speed impact provided by the present invention has a density of <5.1 g / cm³. 3 It has a density that is more than 30% lower than that of traditional iron-based alloys used in the same environment, resulting in significant weight reduction for the structure.

[0022] (3) The titanium-based lightweight multi-principal alloy provided by the present invention can be processed by using general melting, hot working and heat treatment equipment, and is easy to industrialize; the processing and preparation cost is similar to that of traditional titanium alloys. Attached Figure Description

[0023] To more clearly illustrate the technical solutions implemented in this invention, the accompanying drawings used in the embodiments of this invention will be briefly explained below. Obviously, the drawings described below are merely some embodiments of this invention. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0024] Figure 1 Photographs of the microstructure of a titanium-based multi-principal-element alloy in Example 2 of this invention;

[0025] Figure 2 Comparative Example 1: Microstructure of a titanium-based multi-principal-element alloy;

[0026] Figure 3 Comparative Example 2: Microstructure of a titanium-based multi-principal-element alloy;

[0027] Figure 4 Comparative Example 3: Microstructure of titanium-based multi-principal-element alloy. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The features of various aspects of the embodiments of the present invention will now be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can also be practiced without these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples. The invention is not limited to any specific setups and methods provided below, but covers all improvements, substitutions, etc., to product structures and methods without departing from the spirit of the invention.

[0030] In the various accompanying drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessarily obscuring the invention.

[0031] The atomic percentages of titanium-based multi-principal-element alloys in the following examples and comparative examples are shown in Table 1. The balance is titanium and unavoidable microstructure elements.

[0032] Table 1 Alloy composition

[0033]

[0034] Example 1:

[0035] According to the chemical composition in Table 1 of this embodiment, the raw materials were weighed, and an alloy ingot with a diameter of 280 mm was prepared by a three-stage vacuum consumable melting method. The alloy ingot was then forged, with the billet preheated at 1150°C, and the deformation per forging controlled at over 75%, with a deformation rate of 1 second. -1 ~1.5s -1 The final temperature is controlled above 1000℃, and the grain size after billet preparation is controlled at around 150μm; then, precision forging is performed at 900℃, with a deformation amount of 96% and a deformation rate of 0.05s. -1 ~0.1s -1 A titanium-based multi-principal-element alloy bar with a diameter of 120 mm and resistant to high-speed impact was obtained.

[0036] The density of this titanium-based multi-principal-element alloy was tested to be 4.78 g / cm³. 3 The alloy microstructure is mainly composed of BCC structure with an average grain size of 85 μm; under quasi-static conditions, the strength-ductility product reaches 12000 MPa%; under dynamic impact conditions, the strength reaches 1600 MPa and the 5200s resuscitation strength reaches 5200 MPa. -1 At that time, the material is not damaged, and the absorbed energy reaches 680 J / cm². 3 .

[0037] Example 2:

[0038] According to the chemical composition in Table 1 of this embodiment, the raw materials were weighed, and an alloy ingot with a diameter of 650 mm was prepared by a three-stage vacuum consumable melting method. The alloy ingot was then forged, with the billet preheated at 1150°C, and the deformation per forging controlled at over 75%, with a deformation rate of 1 second. -1 ~1.5s -1 The final temperature is controlled above 1000℃, and the grain size after billet preparation is controlled at around 150μm; then, precision forging is performed at 900℃, with a deformation amount of 96% and a deformation rate of 0.05s. -1 ~0.1s -1 A titanium-based multi-principal-element alloy bar with a diameter of 320 mm and resistant to high-speed impact was obtained.

[0039] The density of this titanium-based multi-principal-element alloy was tested to be 4.85 g / cm³. 3 The alloy microstructure is mainly composed of BCC structure, with an average grain size of approximately 90 μm. Under quasi-static conditions, the strength-ductility product reaches 13000 MPa%; under dynamic impact conditions, the strength reaches 1650 MPa, and the 5500s saturation point... -1 At that time, the material is not damaged, and the absorbed energy reaches 720 J / cm². 3 .

[0040] Example 3:

[0041] According to the chemical composition in Table 1 of this embodiment, the raw materials were weighed, and an alloy ingot with a diameter of 280 mm was prepared by a three-stage vacuum arc remelting method. The alloy ingot was then forged, with the billet preheated at 1150°C, and the deformation per forging controlled at over 78%, with a deformation rate of 0.5 s. -1 ~1.5s -1 The terminal temperature is controlled above 1000℃, and the grain size after billet preparation is controlled at around 150μm; then, precision forging is performed at 900℃ with a deformation amount of 95% and a deformation rate of 0.05s. -1 ~0.1s -1 A titanium-based multi-principal-element alloy bar with a diameter of 120 mm and resistant to high-speed impact was obtained.

[0042] The density of this titanium-based multi-principal-element alloy was tested to be 4.83 g / cm³. 3 The alloy microstructure is mainly composed of BCC structure, with an average grain size of approximately 95 μm in the bars. Under quasi-static conditions, the strength-ductility product reaches 11500 MPa%; under dynamic impact conditions, the strength reaches 1650 MPa and the 5500s saturation point. -1 At that time, the material is not damaged, and the absorbed energy reaches 700 J / cm². 3 .

[0043] Example 4:

[0044] According to the chemical composition in Table 1 of this embodiment, the raw materials were weighed, and an alloy ingot with a diameter of 280 mm was prepared by a three-stage vacuum arc remelting method. The alloy ingot was then forged, with the billet preheated at 1150°C, and the deformation per forging controlled at over 75%, with a deformation rate of 0.5 s. -1 ~1.5s -1 The final temperature is controlled above 1000℃, and the grain size after billet preparation is controlled at around 150μm; then, precision forging is performed at 800℃ with a deformation amount of 95% and a deformation rate of 0.05s. -1 ~0.1s -1 A titanium-based multi-principal-element alloy bar with a diameter of 120 mm and resistant to high-speed impact was obtained.

[0045] The density of this titanium-based multi-principal-element alloy was tested to be 4.9 g / cm³. 3 The alloy microstructure is mainly composed of BCC structure, with an average grain size of approximately 90 μm in the bars; under quasi-static conditions, the strength-ductility product reaches 12000 MPa%; under dynamic impact conditions, the strength reaches 1750 MPa, and the 5200s yield is... -1 At that time, the material is not damaged, and the absorbed energy reaches 670 J / cm². 3 .

[0046] Example 5:

[0047] According to the chemical composition in Table 1 of this embodiment, the raw materials were weighed, and an alloy ingot with a diameter of 650 mm was prepared by a three-stage vacuum arc remelting method. The alloy ingot was then forged, with a preheating temperature of 1150°C, a deformation amount of 95%, and a deformation rate of 0.05 s. -1 ~0.1s -1 The terminal temperature is controlled above 1000℃, and the grain size after billet preparation is controlled at around 150μm; then, precision forging is performed at 900℃ with a deformation amount of 95% and a deformation rate of 0.05s. -1 ~0.1s -1 A titanium-based multi-principal-element alloy bar with a diameter of 320 mm and resistant to high-speed impact was obtained.

[0048] The density of this titanium-based multi-principal-element alloy was tested to be 4.7 g / cm³. 3 The alloy microstructure is mainly composed of BCC structure, with an average grain size of approximately 80 μm in the bars; under quasi-static conditions, the strength-ductility product reaches 12500 MPa%; under dynamic impact conditions, the strength reaches 1600 MPa, and the 5000s saturation point... -1 At that time, the material is not damaged, and the absorbed energy reaches 680 J / cm². 3 .

[0049] Comparative Example 1:

[0050] The chemical composition of this comparative example is the same as that of Example 2, and the forging process is the same. The difference lies in the billet preheating stage, where the billet preheating temperature is 1150°C, the deformation per forging is controlled at 50%, and the deformation rate is within 1 second. -1 ~1.5s -1 The terminal temperature is controlled above 1000℃.

[0051] Testing revealed that the bar material exhibited non-uniform grain size; under quasi-static conditions, the strength-ductility product reached 10500 MPa%; under dynamic impact conditions, the strength reached 1500 MPa, and the critical strain rate for impact failure reached 4800 s⁻¹. -1 The absorbed energy is 610 J / cm. 3 .

[0052] Comparative Example 2:

[0053] The chemical composition of this comparative example is the same as that of Example 2, the difference being that after the ingot is opened, the temperature during the fine forging stage is 900°C, the deformation is 75%, and the deformation rate is 0.05s. -1 ~0.1s -1 .

[0054] Testing revealed that the bar material exhibited non-uniform grain size; under quasi-static conditions, the strength-ductility product reached 10000 MPa%; under dynamic impact conditions, the strength reached 1500 MPa, and the critical strain rate for impact failure reached 4800 s⁻¹.-1 The absorbed energy is 620 J / cm. 3 .

[0055] Comparative Example 3:

[0056] The chemical composition of this comparative example is the same as that of Example 2, the difference being that the temperature during the fine forging stage after the ingot is opened is 900°C, the deformation is 96%, and the deformation rate is 0.5s. -1 ~1s -1 .

[0057] Testing revealed that the bar material exhibited non-uniform grain size; under quasi-static conditions, the strength-ductility product reached 9500 MPa%; under dynamic impact conditions, the strength reached 1500 MPa, and the critical strain rate for impact failure reached 4700 s⁻¹. -1 The absorbed energy is 590 J / cm. 3 .

[0058] like Figures 1 to 4 The organizational structure shown in the embodiments and comparative examples is as follows: Figure 1 It can be seen that a refined and homogeneous microstructure was obtained, achieving the microstructure control target of the lightweight multi-principal element alloy of this invention, resulting in excellent performance. Figure 2-4 Due to process control issues, the final microstructure is uneven, resulting in relatively poor performance. The difference in performance between Comparative Example 1 and Example 2 is mainly due to the control of the average grain size of the bars. Grain size is closely related to the thermomechanical treatment process; therefore, it is necessary to simultaneously control the chemical composition and preparation process to achieve the high-speed impact resistance performance indicators proposed in this invention.

[0059] The performance of the embodiments and comparative examples of the present invention is shown in Table 2.

[0060] Table 2

[0061]

[0062] The high-speed impact resistant titanium-based multi-principal-element alloy of this invention has a density of less than 5.1 g / cm³. 3 Under quasi-static conditions, it exhibits strong-plasticity matching; under dynamic impact conditions, its strength reaches over 1600 MPa, and the critical strain rate for impact failure reaches 5000 s⁻¹. -1 The absorption energy reaches 650 J / cm³. 3 Compared with traditional titanium alloys, it has significant advantages in dynamic mechanical properties and has great application potential in the extreme high-speed impact structural components required for new aerospace structural components.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A titanium-based lightweight multi-principal-element alloy resistant to high-speed impact, characterized in that: The titanium-based multi-principal alloy is mainly composed of BCC structural phases, with a BCC structural phase content of over 95% and an average grain size of less than 100 μm. The chemical composition of the titanium-based multi-principal alloy, in atomic percentage, is: Ti: 60%~75%, Al: 10%~20%, V+Fe+Mo+Cr+Nb+Zr: 11%~25%, with at least two elements comprising more than 5%, and the balance being unavoidable impurities. The density of the high-speed impact resistant titanium-based multi-principal alloy is less than 5.1 g / cm³. 3 Under dynamic impact conditions, the strength is above 1600 MPa, and the critical strain rate for impact failure is 5000 s⁻¹. -1 The absorption energy is above 650 J / cm. 3 above; The preparation method of the high-speed impact resistant titanium-based lightweight multi-principal element alloy includes the following steps: S1: Obtain alloy ingots by means of vacuum consumable melting, solidification melting, or consumable melting + solidification melting; S2: Forging is used to prepare the required billet, forging or structural part; During the billet preparation stage, the hot working temperature of the billet is controlled between 1000℃ and 1150℃, the deformation per heat treatment is controlled to be above 75%, and the deformation rate is within 0.5s. -1 ~1.5s -1 After billet preparation, the average grain size is controlled below 200 μm; in the final forming stage, the hot working temperature of the billet is controlled at 800℃~900℃, the deformation amount is controlled above 95%, and the deformation rate is below 0.01s. -1 ~0.1s -1 Annealing is performed to obtain an alloy material with an average grain size of less than 100 μm.

2. The titanium-based multi-principal-element alloy according to claim 1, characterized in that: The chemical composition of the titanium-based multi-principal-element alloy, in terms of atomic percentage, contains: V+Fe+Mo+Cr+Nb+Zr in the range of 12% to 22%.

3. The titanium-based multi-principal-element alloy according to claim 1, characterized in that: The titanium-based multi-principal-element alloy has an Al content in the range of 10% to 12.9%.

4. The titanium-based multi-principal-element alloy according to claim 1, characterized in that: The V content in the chemical composition of the titanium-based multi-principal-element alloy is in the range of 5% to 10%.

5. The titanium-based multi-principal-element alloy according to claim 1, characterized in that: The Cr content in the titanium-based multi-principal-element alloy is in the range of 5% to 7.8%.

6. The titanium-based multi-principal-element alloy according to claim 1, characterized in that: The Nb content in the titanium-based multi-principal-element alloy is in the range of 5% to 9.8%.

7. The titanium-based multi-principal-element alloy according to claim 1, characterized in that: The titanium-based multi-principal-element alloy exhibits a strength-ductility product of 9000 MPa under quasi-static conditions.

8. The titanium-based multi-principal-element alloy according to claim 1, characterized in that: The oxygen content in the ingot is controlled to be below 0.07 wt.%.

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