Lightweight refractory multi-principal-element alloy with excellent high-temperature creep property and preparation method and application of lightweight refractory multi-principal-element alloy

Abstract

The invention belongs to the technical field of alloys, and provides a lightweight refractory multi-principal-element alloy with excellent high-temperature creep property, and a preparation method and application thereof. The general formula of the light refractory multi-principal-element alloy with the excellent high-temperature creep property is TiaVbAlcCrdMoe, wherein 43% < = a < = 48%, 43% < = b < = 48%, 2% < = c < = 8%, 2% < = d < = 8% and 1% < = e < = 5%, a + b + c + d + e = 100%, and a, b, c, d and e are mole percentages. The alloy presents an isometric crystal structure in a complete recrystallization state in a thermal mechanical treatment state, the phase structure is a single-phase body-centered cubic BCC structure, the alloy has low density and shows excellent creep property at 650 DEG C / 100 MPa, the creep time exceeds 90 h, and the creep elongation is lower than 10%.

Description

Technical Field

[0001] This invention belongs to the field of alloy technology and relates to a lightweight refractory multi-principal element alloy with excellent high-temperature creep properties, its preparation method and applications. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Lightweight refractory multi-principal-element alloys (LRM-HEAs) are mainly composed of low-density refractory elements such as Ti, Zr, V, Nb, Ta, and Mo. They combine low density, high strength, excellent high-temperature stability, and radiation resistance, making them a promising new generation of high-temperature structural materials.

[0004] Currently, systems represented by NbMoTaTiZr and NbMoTaWV have been selected, with densities generally below 9 g / cm³ and compressive strengths exceeding 1.5 GPa. Some systems maintain excellent strength even at 1200°C. Some single-phase solid solution refractory high-entropy alloys exhibit excellent yield strength at high temperatures (>600°C). However, most research focuses on the tensile properties of these alloys, with limited studies on their creep behavior and low creep performance. Therefore, there is an urgent need to develop a lightweight refractory multi-principal element alloy with excellent high-temperature creep properties.

[0005] A study has disclosed a metastable β-type titanium alloy with ultra-high toughness Ti-Al-V-Cr-Mo system, but the alloy is mainly composed of Ti, and its high-temperature creep performance still needs to be improved. Summary of the Invention

[0006] To address the issues of high density and low creep performance in current refractory high-entropy alloys, a lightweight refractory multi-principal-element alloy with excellent high-temperature creep performance is proposed. After thermomechanical treatment, this alloy exhibits a fully recrystallized equiaxed crystal structure with a single-phase body-centered cubic (BCC) structure. It not only has a low density but also demonstrates excellent creep performance at 650℃.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a lightweight refractory multi-principal element alloy with excellent high-temperature creep properties, wherein the general formula of the lightweight refractory multi-principal element alloy is Ti. a V b Al c Cr d Mo e, where 43%≤ a ≤48%, 43%≤ b ≤48%, 2%≤ c ≤8%, 2%≤ d ≤8%, and 1%≤ e ≤5%, and a+b+c+d+e=100%.

[0008] This invention uses Ti and V as the main elements. Taking advantage of the fact that V has a higher melting point than Ti, the addition of V effectively improves the high-temperature creep performance of the alloy while maintaining its low density.

[0009] A second aspect of the present invention provides a method for preparing the above-mentioned lightweight refractory multi-principal element alloy with excellent high-temperature creep properties, comprising: Weigh out each elemental metal in proportion, mix them evenly, and melt them in a vacuum induction electromagnetic levitation melting furnace under an inert gas atmosphere to obtain a cast alloy ingot. The cast alloy ingot is hot-rolled and annealed to obtain the final product.

[0010] A third aspect of the present invention provides the application of the above-described lightweight refractory multi-principal alloy with excellent high-temperature creep properties or the lightweight refractory multi-principal alloy prepared by the above-described method in the aerospace field, including: preparing spacecraft thermal protection systems or high-temperature load-bearing structures.

[0011] Beneficial effects of the present invention 1) This invention selects low-density, high-melting-point refractory elements Ti, V, Cr and Mo, and low-density reactive element Al as the main components, and obtains a single-phase refractory multi-principal-element alloy density through vacuum induction suspension melting. ρ ≤5.3g / cm 3 By controlling the atomic ratio of the matrix and Mo, a series of lightweight refractory multi-principal element alloys were obtained. 2) The lightweight refractory multi-principal alloy of the present invention with excellent high-temperature creep performance has a single-phase BCC structure and exhibits good creep performance at high temperature (650℃). The creep time of the alloy at 650℃ / 100MPa exceeds 90h and the creep elongation is less than 10%, which exceeds the high-temperature creep performance of most refractory high-entropy alloys. 3) The lightweight refractory multi-principal element alloy of the present invention exhibits excellent high-temperature creep performance and can be used as a candidate material for high-temperature structural components.

[0012] 4) This invention uses Ti and V as the main elements. Taking advantage of the fact that V has a higher melting point than Ti, the addition of V effectively improves the high-temperature creep performance of the alloy while maintaining its low density.

[0013] In summary, this invention obtains a series of lightweight refractory multi-principal element alloys by controlling the atomic ratio of the matrix and Mo. The lightweight refractory multi-principal element alloys of this invention have excellent high-temperature creep properties, with low density and excellent high-temperature creep properties, and are expected to realize the engineering application of refractory multi-principal element alloys. Attached Figure Description

[0014] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0015] Figure 1 Example 1 Ti 45 V 45 Al4Cr4Mo2 lightweight refractory multi-principal element alloy ingot; Figure 2 Example 1 Ti 45 V 45 Creep curve of Al4Cr4Mo2 lightweight refractory multi-principal element alloy at 650℃ / 100MPa. Figure 3 Example 1 Ti 45 V 45 XRD pattern of Al4Cr4Mo2 lightweight refractory multi-principal element alloy; Figure 4 Example 1 Ti 45 V 45 Microscopic morphology images of Al4Cr4Mo2 lightweight refractory multi-principal element alloy; Figure 5 Example 2 Ti 44 V 44 Creep curve of Al4Cr4Mo4 lightweight refractory multi-principal element alloy at 650℃ / 100MPa. Figure 6 Example 2 Ti 44 V 44 XRD pattern of Al4Cr4Mo4 lightweight refractory multi-principal element alloy; Figure 7 Example 2 Ti 44 V 44 Microscopic morphology image of Al4Cr4Mo4 lightweight refractory multi-principal element alloy. Detailed Implementation

[0016] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods in the art or product instructions. Similarly, unless otherwise specified, the test methods of this invention are performed in accordance with conventional methods in the art or industry-standard methods or practices. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0018] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," "consisting of," etc., and similar meanings.

[0019] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0020] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0021] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0022] In this specification, the terms "optional" or "optional" are used to indicate the use or omission of certain substances, components, procedures, application conditions, etc.

[0023] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0024] Unless otherwise specified, all reagents or instruments used in this instruction manual are commercially available products.

[0025] This invention provides a lightweight refractory multi-principal element alloy with excellent high-temperature creep properties, wherein the general formula of the lightweight refractory multi-principal element alloy is Ti. a V b Al c Cr d Mo e , where 43%≤ a ≤48%, 43%≤ b ≤48%, 2%≤ c ≤8%, 2%≤ d ≤8%, and 1%≤ e ≤5%, and a+b+c+d+e=100%.

[0026] In some embodiments, the lightweight refractory multi-principal alloy has a single-phase BCC structure, which not only has a low density but also exhibits excellent creep properties.

[0027] In some embodiments, the density of the lightweight refractory multi-principal alloy is 5-6 g / cm³. 3 The present invention has a lower alloy density, which can better meet the requirements of lightweight in the aerospace and nuclear energy fields.

[0028] In some embodiments, the lightweight refractory multi-principal-element alloy exhibits a creep time exceeding 80-95 hours at 650°C / 100MPa, with a creep elongation of 5-10%. This invention possesses superior high-temperature creep performance and is applicable to high-temperature resistant components such as aero-engines and ground-based gas turbines, enabling it to better withstand the coupling effects of high temperature and stress, thus reducing the risk of creep fracture.

[0029] This invention provides a method for preparing the above-mentioned lightweight refractory multi-principal element alloy with excellent high-temperature creep properties, comprising: Weigh out each elemental metal in proportion, mix them evenly, and melt them in a vacuum induction electromagnetic levitation melting furnace under an inert gas atmosphere to obtain a cast alloy ingot. The cast alloy ingot is hot-rolled and annealed to obtain the final product.

[0030] Furnace cleaning can remove residual impurities and combustibles, avoiding the risk of deflagration. In some embodiments, furnace cleaning is performed before smelting, including: evacuating the suspension furnace to a vacuum level of 4.5 × 10⁻⁶. -3 ~5.5×10 -3 Pa, then purged with argon gas to -0.06 to -0.04 MPa, and then evacuated to 4.5 × 10 Pa. -3 ~5.5×10 -3 Pa, to ensure the smooth progress of subsequent suspension melting.

[0031] The magnitude of the current affects the efficiency of melting and the quality of the product. Therefore, this invention studies the current, the duration of the melting arc, and the number of melting cycles. In some embodiments, the melting conditions are: the current is 400~600A, the melting arc lasts for 2~3 minutes each time, and the melting is repeated 2~3 times to obtain better high-temperature creep performance.

[0032] Hot rolling can improve the plasticity of materials, improve their mechanical properties, eliminate internal stress, and improve surface quality. Therefore, this invention studies the temperature of hot rolling. In some embodiments, the hot rolling temperature is 500~700℃ to give the alloy better mechanical properties.

[0033] Annealing can adjust the microstructure of an alloy and improve its mechanical properties. Therefore, this invention studies the annealing temperature and time. In some embodiments, the annealing temperature is 700~900℃, the annealing time is 1.5~2.5h, and water quenching is performed to obtain a better microstructure and high-temperature creep performance.

[0034] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0035] Example 1 This embodiment provides a lightweight, refractory, multi-principal-element alloy with excellent high-temperature creep properties, and its chemical formula is Ti. 45 V 45 The specific preparation method for Al4Cr4Mo2 is as follows: Step 1: Composition Design and Raw Material Selection: Low-density refractory elements Ti and V were selected as the main alloying elements, with trace amounts of Al, Cr, and Mo added to the matrix. The purity of all selected raw materials was greater than or equal to 99.95 wt.%. The selected elemental metals Ti, V, Al, Cr, and Mo were polished using different grades (240#, 400#, and 600#) of SiC sandpaper to remove oxide scale and stains from the raw material surfaces.

[0036] Step 2, Batching: Convert the molar percentage of the lightweight refractory multi-principal element alloy to a mass percentage. Based on a total raw material mass of 2000 g, the weighed masses of the metallic raw materials Ti, V, Al, Cr and Mo are 869.70 g, 925.31 g, 43.59 g, 83.95 g and 77.45 g, respectively, with a weighing error of ±0.01 g.

[0037] Step 3, Smelting: Place the raw materials prepared in Step 2 into the copper crucible of the vacuum induction electromagnetic levitation furnace, and mix Ti, V, Al, Cr and Mo raw materials evenly; first clean the furnace chamber, and then evacuate to 5×10 -3 Pa, then argon gas was introduced to -0.05 MPa, and then vacuum was applied again to 5 × 10⁻⁵ MPa. -3 Pa, the purpose is to remove excess oxygen in the furnace; start melting, slowly increase the current to 500A and maintain the current for 3 minutes, then slowly decrease the current to 0A; after the ingot cools, open the furnace door and take out the ingot, turn the ingot over and put it back into the copper crucible, repeat step three; the alloy ingot is repeatedly melted 3 times to ensure that the alloy is fully mixed and uniform.

[0038] Step 4, thermomechanical treatment: Cut the prepared alloy ingot into blocks with a thickness of 10 mm, a length of 50 mm, and a width of 30 mm. Hold the blocks at 600℃ for 10 min, then roll them with a reduction of 0.02 mm per pass and a total reduction of 85%. After rolling, anneal at 800℃ for 2 h and then water quench them.

[0039] The lightweight refractory multi-principal element alloy with excellent high-temperature creep properties provided in Example 1 ( ρ = 5.23 g / cm 3 Thermomechanically treated samples were subjected to high-temperature creep performance (650℃ / 100MPa) testing and crystal structure microstructure characterization. Figure 1 Example 1 Ti 45 V 45 Al4Cr4Mo2 lightweight refractory multi-principal element alloy ingot Figure 2 Example 1 Ti 45 V 45 The high-temperature creep performance curves of the lightweight refractory multi-principal element alloy Al4Cr4Mo2 at 650℃ / 100MPa are shown in the figure. The results indicate that at 650℃ / 100MPa, the creep time of Example 1 exceeds 80h, and the creep elongation is less than 10%. Figure 3 Example 1 Ti 45 V 45 The XRD pattern of the Al4Cr4Mo2 lightweight refractory multi-principal element alloy shows that Example 1 has a single-phase BCC crystal structure. Electron probe microanalysis (EPMA) was performed on Example 1. Figure 4 This is Example 1 Ti 45 V 45 Microscopic images of Al4Cr4Mo2 lightweight refractory multi-principal-element alloy. Example 1 shows a typical fully recrystallized equiaxed crystal structure after thermomechanical treatment.

[0040] Example 2 This embodiment describes a lightweight, refractory, multi-principal-element alloy with excellent high-temperature creep properties, its chemical formula being Ti. 44 V 44 Al4Cr4Mo4, its density ρ = 5.31 g / cm 3 The preparation method of this alloy is the same as that of Example 1.

[0041] Figure 5 Example 2 Ti 44 V 44 The high-temperature creep performance curves of the lightweight refractory multi-principal element alloy Al4Cr4Mo4 at 650℃ / 100MPa are shown in the figure. The results indicate that at 650℃ / 100MPa, the creep time of Example 1 exceeds 90h, and the creep elongation is less than 8%. Figure 6 Example 2 Ti 44 V 44 XRD pattern of Al4Cr4Mo4 lightweight refractory multi-principal element alloy. The pattern shows that Example 2 still has a single-phase BCC crystal structure. Figure 7 This is Example 2 Ti 44 V 44 Microscopic morphology images of Al4Cr4Mo4 lightweight refractory multi-principal element alloy. As can be seen from the images, Example 2 has an equiaxed crystal structure. Compared with Example 1, the grain size of Example 2 is smaller, indicating that the increase of Mo content will refine the grains.

[0042] Comparative Example 1 The titanium alloy prepared using the scheme of Example 1 of patent CN118389900A has poor high-temperature creep performance compared to Example 1.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A lightweight, refractory multi-principal element alloy with excellent high-temperature creep properties, characterized in that, The general formula of the lightweight refractory multi-principal element alloy is Ti. a V b Al c Cr d Mo e , where 43%≤ a ≤48%, 43%≤ b ≤48%, 2%≤ c ≤8%, 2%≤d ≤8%, and 1%≤ e ≤5%, and a+b+c+d+e=100%.

2. The lightweight refractory multi-principal element alloy with excellent high-temperature creep properties as described in claim 1, characterized in that, The lightweight, refractory multi-principal-element alloy has a single-phase BCC structure.

3. The lightweight refractory multi-principal element alloy with excellent high-temperature creep properties as described in claim 1, characterized in that, The density of the lightweight refractory multi-principal alloy is 5~6 g / cm³. 3 .

4. The lightweight refractory multi-principal element alloy with excellent high-temperature creep properties as described in claim 1, characterized in that, The lightweight refractory multi-principal-element alloy has a creep time of more than 80-95 hours at 650℃ / 100MPa and a creep elongation of 5-10%.

5. A method for preparing a lightweight refractory multi-principal element alloy with excellent high-temperature creep properties as described in any one of claims 1-4, characterized in that, include: Weigh out each elemental metal in proportion, mix them evenly, and melt them in a vacuum induction electromagnetic levitation melting furnace under an inert gas atmosphere to obtain a cast alloy ingot. The cast alloy ingot is hot-rolled and annealed to obtain the final product.

6. The method for preparing a lightweight refractory multi-principal element alloy with excellent high-temperature creep properties as described in claim 5, characterized in that, Before the smelting process, the furnace is cleaned, including: evacuating the levitation furnace to a vacuum level of 4.5 × 10⁻⁶. -3 ~5.5×10 -3 Pa, then purged with argon gas to -0.06 to -0.04 MPa, and then evacuated to 4.5 × 10 Pa. -3 ~5.5×10 -3 Pa.

7. The method for preparing a lightweight refractory multi-principal element alloy with excellent high-temperature creep properties as described in claim 5, characterized in that, The melting conditions are: current of 400~600A, melting arc duration of 2~3 minutes each time; repeated melting 2~3 times.

8. The method for preparing a lightweight refractory multi-principal element alloy with excellent high-temperature creep properties as described in claim 5, characterized in that, The hot rolling temperature is 500~700℃.

9. The method for preparing a lightweight refractory multi-principal element alloy with excellent high-temperature creep properties as described in claim 5, characterized in that, The annealing temperature is 700~900℃, the annealing time is 1.5~2.5h, and the annealing is water quenched.

10. The application of the lightweight refractory multi-principal alloy with excellent high-temperature creep properties as described in claims 1-4, or the lightweight refractory multi-principal alloy prepared by the method described in any one of claims 5-9, in the aerospace field, characterized in that, include: Prepare thermal protection systems or high-temperature load-bearing structures for spacecraft.

Images