Titanium-based multi-principal-element alloy with tensile plasticity and high specific impact absorption energy and preparation method of titanium-based multi-principal-element alloy

Abstract

The invention discloses a titanium-based multi-principal-element alloy with tensile plasticity and high specific impact absorption energy and a preparation method of the titanium-based multi-principal-element alloy. Belongs to the field of titanium-based multi-principal-element alloys, and the alloy comprises the following chemical components by atomic percent: 50 < = a < = 70, 10 < = b < = 20, 5 < = c < = 15, 5 < = d < = 15, 5 < = e < = 15, 0 < = f < = 10, 90 < = x < = 100, and a + b + c + d + e + f = 100. Through preparation of a vacuum induction melting furnace and combination of element composition design, the content and the form of a B2 coherent precipitated phase are introduced into the alloy and regulated and controlled. The density of the obtained alloy is 4.8 g / cm < 3 >, the quasi-static tensile elongation can reach 15% or above, the dynamic compressive strength of the alloy at the strain rate of 4000 s <-1 > exceeds 1700 MPa, the fracture strain reaches 34%, the specific impact absorption energy reaches 90 J / g, and the alloy shows the excellent energy absorption characteristic without subsequent heat treatment and deformation optimization.

Description

Technical Field

[0001] This invention belongs to the technical field of titanium-based multi-principal alloys, and particularly relates to a titanium-based multi-principal alloy with tensile plasticity and high specific impact absorption energy, and its preparation method. Background Technology

[0002] With the rapid development of aerospace, automotive, and other industries, future high-end equipment may face even harsher service environments, especially extreme high-speed impact environments, which place more stringent demands on the performance of structural materials. Traditional metallic structural materials, such as magnesium alloys, aluminum alloys, and titanium alloys, while widely used, exhibit varying degrees of performance limitations when subjected to high strain rate impact loads. These materials may have low dynamic strength or be sensitive to adiabatic shear, significantly restricting their application prospects as critical protective or load-bearing components in extreme impact environments. Therefore, there is an urgent need to develop a lightweight, high-strength, high-toughness metallic material with excellent impact resistance.

[0003] Multi-principal element alloys, also known as high-entropy alloys, are a novel material system that breaks with traditional alloy design concepts. Through the equimolar or near-equimolar mixing of multiple principal elements, they exhibit unique microstructure and performance characteristics. Titanium-based multi-principal element alloys developed based on this concept have been proven to possess excellent dynamic mechanical properties under high strain rate environments, showing potential applications in armor protection. Specific impact absorption energy is a crucial indicator for evaluating a material's protective effectiveness and lightweight potential; it refers to the energy absorbed per unit mass of material under impact conditions. Introducing a second phase (such as a precipitated phase) into titanium-based multi-principal element alloys is an effective strengthening method to improve their dynamic strength and impact absorption energy. However, this strengthening method often severely impairs the alloy's tensile plasticity, limiting its application at high strain rates. Therefore, overcoming the inverse relationship between strength and plasticity and developing a titanium-based multi-principal element alloy that combines good tensile plasticity with high specific impact absorption energy has become a critical scientific problem and technological bottleneck in this field.

[0004] In existing technologies, while some studies have attempted to control the microstructure of titanium-based multi-principal alloys to balance their properties through complex post-treatment heat treatments or drastic plastic deformation processes, these methods are often cumbersome, costly, and difficult to precisely control the morphology and distribution of precipitated phases, resulting in limited and unstable performance improvements. Therefore, there is an urgent need for a new alloy composition design and preparation method that can fundamentally achieve a synergistic improvement in the tensile plasticity and high specific impact absorption energy of titanium-based multi-principal alloys without relying on complex post-treatment processes. Summary of the Invention

[0005] The purpose of this invention is to address the problems of high density and difficulty in simultaneously achieving high impact absorption energy and tensile plasticity in existing titanium-based multi-principal element alloys. This invention proposes a titanium-based multi-principal element alloy with tensile plasticity and high specific impact absorption energy, along with its preparation method. The resulting alloy has low density and a quasi-static tensile elongation of over 15%, achieving a tensile elongation of over 15% at 4000 s⁻¹. -1 With a dynamic compressive strength exceeding 1700 MPa under high strain rate and a specific impact absorption energy as high as 90 J / g, it exhibits excellent comprehensive performance and has broad application prospects in fields such as aerospace and vehicle protection where there is an urgent need for lightweight, high-strength, and tough materials.

[0006] To achieve the above objectives, the present invention provides a titanium-based multi-principal-element alloy with tensile plasticity and high specific impact absorption energy, the chemical composition of which, by atomic percentage, is (Ti a Al b V c Cr d Nb e Mo f ) x Zr 100-x , where 50≤a≤70, 10≤b≤20, 5≤c≤15, 5≤d≤15, 5≤e≤15, 0≤f≤10, 90≤x≤100, and a+b+c+d+e+f=100.

[0007] Furthermore, the microstructure of the alloy comprises a body-centered cubic matrix and a B2 precipitate phase, wherein the volume fraction of the B2 phase in the alloy is 5% to 30%.

[0008] Furthermore, the atomic percentage content of Zr in the alloy is 3% to 7%.

[0009] Furthermore, the density of the alloy is in the range of 4.8 g / cm³. 3 ~5.2 g / cm 3 The quasi-static tensile elongation reaches 15%.

[0010] Furthermore, the alloy at 4000 s -1 The dynamic compressive strength under high strain rate exceeds 1700 MPa, and the specific impact absorption energy is as high as 90 J / g.

[0011] Furthermore, the titanium-based multi-principal-element alloy possesses both tensile plasticity and high specific impact absorption energy without relying on post-processing.

[0012] The present invention also provides a method for preparing the above-described titanium-based multi-principal-element alloy, comprising the following steps: S1. Batching: Weigh out Ti, Al, V, Cr, Nb, Mo, and Zr metal raw materials according to the atomic percentage of the target alloy; S2. Loading the furnace: Place the prepared raw materials into the magnetic levitation vacuum induction melting furnace; S3. Vacuuming and gas washing: Vacuum the furnace, then fill it with inert protective gas, and absorb the residual impurities in the furnace by melting high-purity Ti blocks. S4. Melting: The alloy is melted under electromagnetic stirring conditions, and the alloy ingot is repeatedly flipped and remelted. S5. Cooling: After melting, the titanium-based multi-principal-element alloy ingot is obtained.

[0013] Furthermore, in step S3, the furnace is evacuated to a vacuum level below 6.7 × 10⁻⁶. -2 Pa, then inert protective gas is introduced until the furnace pressure reaches 6 × 10⁻⁶. -2 MPa.

[0014] Furthermore, in step S4, the number of times the remelting is repeated is 4 to 6, and the melting time for each remelting is 12 to 20 minutes.

[0015] Furthermore, in step S3, the inert protective gas used in the smelting process is high-purity argon, with a purity of not less than 99.999%.

[0016] Compared with the prior art, the present invention has the following advantages and technical effects: 1. This invention designs TiAlVCrNbMoZr titanium-based multi-principal element alloys with different Ti / Al / Zr element contents. The content and morphology of the B2 phase in the alloy are controlled by composition design, and a titanium-based multi-principal element alloy with tensile plasticity and high specific impact absorption energy is designed accordingly.

[0017] 2. The titanium-based multi-principal-element alloy prepared by suspension vacuum induction melting in this invention has a density of 4.8 g / cm³. 3 The tensile elongation under quasi-static conditions reaches 15%; at 4000 s... -1 The dynamic compressive strength under strain rate loading reaches 1700 MPa, and the fracture strain is greater than 35%. At the same time, the specific impact absorption energy of the alloy reaches 90 J / kg, which is higher than that of cast titanium alloys and other titanium-based multi-principal element alloys.

[0018] 3. The preparation method of the titanium-based multi-principal element alloy with tensile plasticity and high specific impact energy absorption of the present invention is simple, and excellent dynamic mechanical properties can be obtained without complex heat treatment and deformation strengthening processes, which has broad industrial application prospects. Attached Figure Description

[0019] Figure 1 TEM images of the microstructures of TiAlVCrNbMoZr-based titanium-based multi-principal-element alloys in Examples 1-5; Figure 2The quasi-static tensile stress-strain curves of the TiAlVCrNbMoZr titanium-based multi-principal element alloys in Examples 1-5 are shown. Figure 3 The TiAlVCrNbMoZr titanium-based multi-principal element alloys of Examples 1-5 were tested at 4000 s. -1 Dynamic compressive stress-strain curves under strain rate. Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] All raw materials used in this invention are not particularly restricted in their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0022] There are no particular restrictions on the purity of any of the raw materials used in this invention. However, this invention preferably uses raw materials of analytical grade or purity commonly used in the field of chemical synthesis.

[0023] This invention provides a titanium-based multi-principal element alloy that combines tensile plasticity and high specific impact absorption energy, the chemical composition of which, by atomic percentage, is (Ti a Al b V c Cr d Nb e Mo f ) x Zr 100-x , where 50≤a≤70, 10≤b≤20, 5≤c≤15, 5≤d≤15, 5≤e≤15, 0≤f≤10, 90≤x≤100, and a+b+c+d+e+f=100.

[0024] The alloy composition, preparation method, microstructure and mechanical properties of the present invention are described in detail below through multiple embodiments and comparative examples.

[0025] Example 1 This embodiment prepares a Zr-free titanium-based multi-principal-element alloy with the chemical composition Ti. 55 Al 10 V8Cr 12 Nb 10 Mo5 (atomic percentage).

[0026] The specific preparation method is as follows: First, accurately weigh high-purity Ti, Al, V, Cr, Nb, and Mo metal raw materials according to the above atomic percentages. Place the prepared raw materials into a magnetic levitation vacuum induction melting furnace and close the furnace door. Evacuate the inside of the equipment to a high vacuum state. When the vacuum degree reaches 6.7 × 10⁻⁶...-2 After Pa, high-purity argon gas is introduced until the protective gas pressure inside the cavity is 6 × 10⁻⁶. -2 The pressure was increased to MPa, and then residual impurities in the cavity were absorbed by melting a high-purity Ti block. Subsequently, the alloy raw material was smelted, with electromagnetic stirring maintained throughout the smelting process to ensure uniform composition. The alloy ingot was flipped and remelted a total of five times, each 15 minutes long. After smelting, the ingot was cooled in the furnace to obtain Ti. 55 Al 10 V8Cr 12 Nb 10 Mo5 alloy ingots.

[0027] The actual density of the alloy ingot was measured to be 5.2 g / cm³. 3 Its microstructure was observed using transmission electron microscopy (TEM), such as... Figure 1 As shown in (a), the alloy has a single body-centered cubic (BCC) solid solution structure, and no obvious second phase precipitation was observed. Figure 2 Its quasi-static tensile stress-strain curve is shown, and its tensile elongation is low, exhibiting a certain degree of brittleness. Figure 3 For it in 4000 s -1 Dynamic compressive stress-strain curves at high strain rates. Tests showed that the alloy has a dynamic compressive strength of 1367 MPa, a dynamic fracture strain of 37%, and a calculated specific impact absorption energy of 70 J / g.

[0028] Example 2 This embodiment prepares a Zr-free titanium-based multi-principal-element alloy with the chemical composition Ti. 55 Al 15 V5Cr 10 Nb 10 Mo5 (atomic percentage).

[0029] The specific preparation method is as follows: First, accurately weigh high-purity Ti, Al, V, Cr, Nb, and Mo metal raw materials according to the above atomic percentages. Place the prepared raw materials into a magnetic levitation vacuum induction melting furnace and close the furnace door. Evacuate the inside of the equipment to a high vacuum state. When the vacuum degree reaches 6.7 × 10⁻⁶... -2 After Pa, high-purity argon gas is introduced until the protective gas pressure inside the cavity is 6 × 10⁻⁶. -2 The pressure was increased to MPa, and then residual impurities in the cavity were absorbed by melting a high-purity Ti block. Subsequently, the alloy raw material was smelted, with electromagnetic stirring maintained throughout the smelting process to ensure uniform composition. The alloy ingot was flipped and remelted a total of five times, each smelting time being 12 minutes. After smelting, the ingot was cooled in the furnace to obtain Ti. 55 Al 15 V5Cr 10 Nb 10Mo5 alloy ingots.

[0030] The actual density of the obtained alloy ingot was measured to be 5.0 g / cm³. 3 Its TEM microstructure is as follows: Figure 1 As shown in (b), the alloy consists of a BCC matrix and an ordered B2 phase. Calculations using image analysis software indicate that the volume fraction of the B2 phase is approximately 12%. Figure 2 As can be seen from the quasi-static tensile curve, this alloy exhibits brittle fracture with no obvious plastic deformation stage. Its dynamic compressive properties (… Figure 3 The results show that the dynamic compressive strength is increased to 1499 MPa, the dynamic fracture strain is 34%, and the specific impact absorption energy is correspondingly increased to 76 J / g.

[0031] Example 3 This embodiment prepares a Zr-free titanium-based multi-principal-element alloy with the chemical composition Ti. 55 Al 20 V5Cr8Nb 10 Mo2 (atomic percentage).

[0032] The specific preparation method is as follows: First, accurately weigh high-purity Ti, Al, V, Cr, Nb, and Mo metal raw materials according to the above atomic percentages. Place the prepared raw materials into a magnetic levitation vacuum induction melting furnace and close the furnace door. Evacuate the inside of the equipment to a high vacuum state. When the vacuum degree reaches 6.7 × 10⁻⁶... -2 After Pa, high-purity argon gas is introduced until the protective gas pressure inside the cavity is 6 × 10⁻⁶. -2 The pressure was increased to MPa, and then residual impurities in the cavity were absorbed by melting a high-purity Ti block. Subsequently, the alloy raw material was smelted, with electromagnetic stirring maintained throughout the smelting process to ensure uniform composition. The alloy ingot was flipped and remelted a total of five times, each smelting time being 20 minutes. After smelting, the ingot was cooled in the furnace to obtain Ti. 55 Al 20 V5Cr8Nb 10 Mo2 alloy ingots.

[0033] The density of the obtained alloy ingot was measured to be 5.0 g / cm³. 3 Its microstructure is as follows: Figure 1 As shown in (c), it still exhibits a BCC+B2 dual-phase structure, but the B2 phase content is significantly increased, with a volume fraction of approximately 28%. This alloy undergoes complete brittle fracture under quasi-static tension. Figure 2 Dynamic compression test () Figure 3 The results showed that its dynamic compressive strength was further increased to 1580 MPa, but the fracture strain dropped sharply to 12%, resulting in a significant decrease in the specific impact absorption energy to 32 J / g. This indicates that although the excessively high B2 phase content improved the strength, it severely deteriorated the toughness.

[0034] Example 4 This embodiment prepares a Zr-free titanium-based multi-principal-element alloy with the chemical composition Ti. 65 Al 15 V5Cr7Nb6Mo2 (atomic percentage).

[0035] The specific preparation method is as follows: First, accurately weigh high-purity Ti, Al, V, Cr, Nb, and Mo metal raw materials according to the above atomic percentages. Place the prepared raw materials into a magnetic levitation vacuum induction melting furnace and close the furnace door. Evacuate the inside of the equipment to a high vacuum state. When the vacuum degree reaches 6.7 × 10⁻⁶... -2 After Pa, high-purity argon gas is introduced until the protective gas pressure inside the cavity is 6 × 10⁻⁶. -2 The pressure was increased to MPa, and then residual impurities in the cavity were absorbed by melting a high-purity Ti block. Subsequently, the alloy raw material was smelted, with electromagnetic stirring maintained throughout the smelting process to ensure uniform composition. The alloy ingot was flipped and remelted a total of five times, each 15 minutes long. After smelting, the ingot was cooled in the furnace to obtain Ti. 65 Al 15 V5Cr7Nb6Mo2 alloy ingot.

[0036] Measurements showed that the density of the resulting alloy ingot decreased to 4.8 g / cm³. 3 . Figure 1 The TEM image in (d) shows that the B2 phase content is reduced to approximately 8%, and the phase is smaller and more diffusely distributed. From... Figure 2 The tensile curves show that the alloy exhibits a quasi-static tensile elongation of 14%, demonstrating good plasticity. Its dynamic compression curve (…) Figure 3 The results showed a dynamic compressive strength of 1335 MPa, a fracture strain of 32%, and a specific impact absorption energy of 77 J / g. Compared to Examples 2 and 3, this composition successfully restored significant tensile plasticity while maintaining a high impact absorption energy.

[0037] Example 5 This embodiment prepares a Zr-containing titanium-based multi-principal-element alloy with the following chemical composition: (Ti 65 Al 15 V3Cr7Nb8Mo2) 95 Zr5 (atomic percentage).

[0038] The specific preparation method is as follows: First, accurately weigh high-purity Ti, Al, V, Cr, Nb, Mo, and Zr metal raw materials according to the above atomic percentages. Place the prepared raw materials into a magnetic levitation vacuum induction melting furnace and close the furnace door. Evacuate the inside of the equipment to a high vacuum state. When the vacuum degree reaches 6.7 × 10⁻⁶... -2After Pa, high-purity argon gas is introduced until the protective gas pressure inside the cavity is 6 × 10⁻⁶. -2 The pressure was increased to MPa, and then the residual impurities in the cavity were absorbed by melting a high-purity Ti block. Subsequently, the alloy raw material was smelted, with electromagnetic stirring maintained throughout the smelting process to ensure uniform composition. The alloy ingot was flipped and remelted a total of five times, each smelting time being 15 minutes. After smelting, the ingot was cooled in the furnace to obtain (Ti 65 Al 15 V3Cr7Nb8Mo2) 95 Zr5 alloy ingots.

[0039] The density of the obtained alloy ingot was measured to be 4.8 g / cm³. 3 . Figure 1 (e) The TEM image shows that the alloy has a BCC+B2 structure, but compared with Examples 1-4, the size of the B2 phase is significantly increased after the introduction of 5% Zr, changing from a fine, dispersed distribution to a coarser, more concentrated distribution. Figure 2 As shown, the quasi-static tensile elongation of this alloy was further improved to 15%. More importantly, its dynamic mechanical properties were synergistically optimized, and the dynamic compression test ( Figure 3 The results show that its dynamic compressive strength is as high as 1726 MPa and its fracture strain is 34%, and the specific impact absorption energy calculated from this is 90 J / g.

[0040] Comparative Example 1 An alloy with the chemical composition Ti was prepared in this comparative example. 45 Al 25 V 10 Cr 10 Nb8Mo2 (atomic percentage).

[0041] The preparation process is the same as in Example 1.

[0042] Measurements revealed significant macroscopic segregation and shrinkage cavities in the obtained alloy ingot. XRD analysis showed that its main phase was a brittle intermetallic compound (such as TiAl phase). The alloy fractured during the machining process, making effective quasi-static tensile and dynamic compression tests impossible.

[0043] Comparative Example 2 An alloy with the chemical composition Ti was prepared in this comparative example. 75 Al5V5Cr5 Nb8Mo2 (atomic percentage).

[0044] The preparation process is the same as in Example 1.

[0045] Measurements showed that the alloy ingot was of good quality, with a density of 5.1 g / cm³. 3TEM observations revealed a single BCC phase with no B2 phase precipitation. Its quasi-static tensile elongation reached 22%, exhibiting excellent plasticity. However, dynamic compression testing showed a dynamic compressive strength of only 1050 MPa and a specific impact absorption energy of 45 J / g. Although this alloy exhibits high plasticity, its insufficient dynamic strength and impact resistance fail to meet the requirements for applications in extreme impact environments.

[0046] Comparative Example 3 An alloy was prepared in this comparative example, the chemical composition of which is (Ti 65 Al 15 V3Cr7Nb8Mo2) 88 Zr 12 (Atomic percentage).

[0047] The preparation process is the same as in Example 5.

[0048] Measurements revealed poor surface quality and the presence of cracks in the alloy ingot. Microstructural analysis uncovered numerous coarse Zr-enriched phases and brittle Laves phases. Its quasi-static tensile elongation was only 2%, its dynamic compressive strength was 1480 MPa, but its fracture strain was only 8%, and its specific impact absorption energy was 25 J / g. This indicates that excessive Zr addition introduces harmful phases, compromising the alloy's plasticity, toughness, and overall properties.

[0049] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A titanium-based multi-principal-element alloy with tensile plasticity and high specific impact absorption energy, characterized in that, Its chemical composition, in atomic percentage, is (Ti a Al b V c Cr d Nb e Mo f ) x Zr 100-x , where 50≤a≤70, 10≤b≤20, 5≤c≤15, 5≤d≤15, 5≤e≤15, 0≤f≤10, 90≤x≤100, and a+b+c+d+e+f=100.

2. The titanium-based multi-principal-element alloy according to claim 1, characterized in that, The microstructure of the alloy comprises a body-centered cubic matrix and a B2 precipitate phase, wherein the volume fraction of the B2 phase in the alloy is 5% to 30%.

3. The titanium-based multi-principal-element alloy according to claim 1, characterized in that, The atomic percentage content of Zr in the alloy is 3% to 7%.

4. The titanium-based multi-principal-element alloy according to claim 1, characterized in that, The density range of the alloy is 4.8 g / cm³. 3 ~5.2 g / cm 3 The quasi-static tensile elongation reaches 15%.

5. The titanium-based multi-principal-element alloy according to claim 1, characterized in that, The alloy at 4000 s -1 The dynamic compressive strength under high strain rate exceeds 1700 MPa, and the specific impact absorption energy is as high as 90 J / g.

6. The titanium-based multi-principal-element alloy according to claim 1, characterized in that, The titanium-based multi-principal-element alloy possesses both tensile plasticity and high specific impact absorption energy without relying on post-processing.

7. A method for preparing a titanium-based multi-principal-element alloy as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Batching: Weigh out Ti, Al, V, Cr, Nb, Mo, and Zr metal raw materials according to the atomic percentage of the target alloy; S2. Loading the furnace: Place the prepared raw materials into the magnetic levitation vacuum induction melting furnace; S3. Vacuuming and gas washing: Vacuum the furnace, then fill it with inert protective gas, and absorb the residual impurities in the furnace by melting high-purity Ti blocks. S4. Melting: The alloy is melted under electromagnetic stirring conditions, and the alloy ingot is repeatedly flipped and remelted. S5. Cooling: After melting, the titanium-based multi-principal-element alloy ingot is obtained.

8. The method according to claim 7, characterized in that, In step S3, the furnace is evacuated to a vacuum level below 6.7 × 10⁻⁶. -2 Pa, then inert protective gas is introduced until the furnace pressure reaches 6 × 10⁻⁶. -2 MPa.

9. The method according to claim 7, characterized in that, In step S4, the number of times the remelting is repeated is 4 to 6, and the melting time for each remelting is 12 to 20 minutes.

10. The method according to claim 7, characterized in that, In step S3, the inert protective gas used in the smelting process is high-purity argon with a purity of not less than 99.999%.

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