Low-density AlNbTaTiZr refractory high-entropy alloy and preparation method thereof

Abstract

The invention relates to a low-density AlNbTaTiZr refractory high-entropy alloy and a preparation method thereof, belongs to the technical field of metal materials, and solves the problem that a refractory high-entropy alloy material obtained by adopting a vacuum arc melting technology in the prior art is difficult to ensure relatively high strength, good plasticity and relatively low density at the same time. The preparation method of the low-density AlNbTaTiZr refractory high-entropy alloy comprises the following steps that S1, raw materials are prepared, and mixed powder is prepared according to the designed molar ratio; s2, alloy ingots are prepared, and the mixed powder is subjected to vacuum melting to obtain the alloy ingots; s3, the alloy ingot is subjected to vacuum melting, and an alloy cast ingot is obtained; and S4, the alloy cast ingot is subjected to heat treatment, and an initial-state sample is obtained. According to the low-density AlNbTaTiZr refractory high-entropy alloy and the preparation method thereof provided by the invention, the obtained alloy material is relatively low in density, relatively high in yield strength, excellent in plasticity and relatively wide in application range.

Description

Technical Field

[0001] The invention relates to the technical field of metal material rolling, in particular to a low-density AlNbTaTiZr refractory high-entropy alloy and a preparation method thereof. Background Art

[0002] With the rapid development of the aerospace field, high-speed aircraft have put forward higher requirements on the mechanical properties of high-temperature resistant structural materials. The existing nickel-based high-temperature alloys can no longer meet the needs of high-temperature construction of the new generation of aircraft. Refractory high-entropy alloys are new high-temperature alloy materials formed by a variety of refractory elements in nearly equal molar ratios. They have the advantages of high strength, good thermal stability, and good wear resistance. Vacuum arc melting technology is an important method for preparing refractory high-entropy alloy materials. However, although the refractory high-entropy alloy materials obtained by vacuum arc melting technology in the prior art can achieve higher strength, it is difficult to ensure good plasticity and low density, which limits the wide application of refractory high-entropy alloy materials in the aerospace field.

[0003] Therefore, in view of the problem that the refractory high entropy alloy material obtained by vacuum arc melting technology in the prior art is difficult to simultaneously ensure high strength, good plasticity and low density, it is necessary to provide a low-density AlNbTaTiZr refractory high entropy alloy and a preparation method thereof. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a low-density AlNbTaTiZr refractory high-entropy alloy and a preparation method thereof. The refractory high-entropy alloy material obtained by vacuum arc melting technology in the prior art is difficult to simultaneously ensure high strength, good plasticity and low density.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] A low-density AlNbTaTiZr refractory high-entropy alloy, wherein the molar percentage of each element is: Al: 12-13.5%, Nb: 25.3-27%, Ta: 8.5-9.0%, Ti: 27-28%, Zr: 26.5-28%, and other inevitable impurities.

[0007] For the above-mentioned low-density AlNbTaTiZr refractory high-entropy alloy, a preparation method of the low-density AlNbTaTiZr refractory high-entropy alloy is provided, comprising the following steps:

[0008] Step S1, preparing raw materials and preparing mixed powder according to a designed molar ratio;

[0009] Step S2, preparing an alloy ingot, vacuum melting the mixed powder to obtain an alloy ingot;

[0010] Step S3: vacuum melting the alloy ingot to obtain an alloy ingot

[0011] Step S4: heat-treat the alloy ingot to obtain an initial sample.

[0012] Furthermore, in step S1, the mixed powder is placed in a three-dimensional mixer for mixing, and high-purity argon gas with a purity of 99.99% is filled in for protection.

[0013] Furthermore, in step S1, the mixing time of the mixed powder in the three-dimensional mixer is 2 to 3 hours.

[0014] Furthermore, in step S3, the alloy ingot is vacuum melted in an arc melting furnace. The chamber of the melting furnace is first evacuated to level 5 vacuum, and then backfilled with argon gas with a purity of 99.99%, and residual oxygen in the chamber is removed using a molten titanium aspirator.

[0015] Furthermore, in step S3, the arc current of vacuum melting is 400-600A.

[0016] Furthermore, in step S3, the alloy ingot is turned over and smelted 7 to 9 times, each time lasting 3 to 4 minutes, and electromagnetic stirring is performed.

[0017] Furthermore, in step S4, the alloy ingot is placed in a heat treatment furnace for heating.

[0018] Furthermore, in step S4, the alloy ingot is heated to 1150-1250° C. in a heat treatment furnace, and then kept at the set temperature for 24 hours.

[0019] Furthermore, in step S4, the alloy ingot is water quenched after the insulation.

[0020] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0021] (1) The low-density AlNbTaTiZr refractory high-entropy alloy of the present invention, by limiting the molar percentage of each element, is beneficial to reducing the density of the alloy material and improving the high-temperature oxidation resistance of the material, which is beneficial to ensuring that the alloy material maintains high strength and excellent plasticity in a high-temperature environment.

[0022] (2) The preparation method of the low-density AlNbTaTiZr refractory high-entropy alloy of the present invention comprises the following steps: vacuum arc melting the alloy ingot, heating it to 1150-1250°C, and keeping it at the set temperature for 24 hours, and then water quenching the ingot. The obtained initial sample has a BCC single-phase structure in terms of microstructure, high-temperature microstructure stability, and a sample density of less than 7 g / cm 3It has high compressive strength and significant plasticity, which is conducive to meeting the dual needs of light weight and high strength in the aerospace field.

[0023] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the following content, and some advantages can be obvious from the description or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the text and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0025] Figure 1 This is a process flow chart of a low-density AlNbTaTiZr refractory high-entropy alloy and a preparation method thereof in Example 1 of the present invention;

[0026] Figure 2 This is a process flow chart of a low-density AlNbTaTiZr refractory high-entropy alloy and its preparation method in Example 2 of the present invention. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used to illustrate the principles of the present invention together with the embodiments of the present invention.

[0028] Example 1

[0029] This embodiment discloses a low-density AlNbTaTiZr refractory high-entropy alloy, in which the molar percentage of each element is: Al: 12-13.5%, Nb: 25.3-27%, Ta: 8.5-9.0%, Ti: 27-28%, Zr: 26.5-28%, and some other inevitable impurities.

[0030] This embodiment discloses a method for preparing the above-mentioned low-density AlNbTaTiZr refractory high entropy alloy, see Figure 1 , the specific steps include:

[0031] Step S1, preparing raw materials; weighing Al powder, Nb powder, Ta powder, Ti powder and Zr powder according to the designed molar ratio and putting them into a three-dimensional mixer for mixing, while filling with high-purity argon gas with a purity of 99.99% for protection to prevent powder oxidation, and uniformly mixing for 2 to 3 hours to obtain a mixed powder;

[0032] Step S2, preparing an alloy ingot; vacuum melting the mixed powder to obtain a block-shaped alloy ingot.

[0033] Step S3, vacuum melting the alloy ingot; vacuum melting the alloy ingot in an arc melting furnace, first evacuating the chamber of the melting furnace to level 5 vacuum, then backfilling it with argon gas with a purity of 99.99%, and using a molten titanium aspirator to remove residual oxygen in the chamber. The arc current is 400-600A, and the alloy ingot is turned over and melted 7-9 times, each time for 3-4 minutes, and electromagnetic stirring is performed to obtain a low-density AlNbTaTiZr refractory high-entropy alloy ingot with full density and high uniformity.

[0034] Step S4, heat treating the alloy ingot; heat treating the low-density AlNbTaTiZr refractory high-entropy alloy ingot obtained by vacuum melting. Exemplarily, the heat treatment equipment is a ceramic fiber box furnace, model BFX-18C. The alloy ingot is placed in the furnace and heated to 1150-1250°C, then kept warm for 24 hours under the set conditions, and then the alloy ingot is water quenched to obtain an initial sample with both high yield strength and excellent plasticity.

[0035] The initial sample obtained in this example has a BCC single-phase structure in terms of microstructure, high-temperature structural stability, and a sample density of less than 7g / cm 3 , compressive strength is higher than 1300MPa, and it has good plasticity.

[0036] Example 2

[0037] This embodiment is another implementation method based on Embodiment 1.

[0038] This embodiment discloses a low-density AlNbTaTiZr refractory high-entropy alloy, in which the molar percentage of each element is: Al: 12%, Nb: 25.5%, Ta: 8.5%, Ti: 27.5%, Zr: 26.5%, and some other inevitable impurities.

[0039] This embodiment discloses a method for preparing the above-mentioned low-density AlNbTaTiZr refractory high entropy alloy, see Figure 1 , the specific steps include:

[0040] Step S1, preparing raw materials; weighing Al powder, Nb powder, Ta powder, Ti powder and Zr powder according to the designed molar ratio and putting them into a three-dimensional mixer for mixing, while filling with high-purity argon gas with a purity of 99.99% for protection to prevent powder oxidation, and obtaining a mixed powder after uniform mixing for 3 hours;

[0041] Step S2, preparing an alloy ingot; vacuum melting the mixed powder to obtain a block-shaped alloy ingot.

[0042] Step S3, vacuum melting the alloy ingot; vacuum melting the alloy ingot in an arc melting furnace, first evacuating the chamber of the melting furnace to level 5 vacuum, and then backfilling it with argon gas with a purity of 99.99%, using a molten titanium aspirator to remove residual oxygen in the chamber, the arc current is 400A, the alloy ingot is turned over and melted 9 times, each time lasting 4 minutes, and electromagnetic stirring is performed to obtain a low-density AlNbTaTiZr refractory high-entropy alloy ingot with full density and high uniformity.

[0043] Step S4, heat treating the alloy ingot; heat treating the low-density AlNbTaTiZr refractory high-entropy alloy ingot obtained by vacuum melting. Exemplarily, the heat treatment equipment is a ceramic fiber box furnace, model BFX-18C. The alloy ingot is placed in the furnace and heated to 1200°C, then kept at 1200°C for 24 hours, and then the alloy ingot is water quenched to obtain an initial sample with both high yield strength and excellent plasticity.

[0044] Referring to Table 1, the initial sample density obtained in this embodiment is 6.9 g / cm 3 The yield strength at room temperature is 1398MPa and the specific yield strength is 202MPa.g -1 .cm 3 , and has a significant compression plasticity of 50%, indicating that the initial sample of this embodiment can not only maintain a high yield strength and excellent compression plasticity at room temperature, but also maintain relatively stable mechanical properties within 600°C, which is conducive to the low-density AlNbTaTiZr refractory high-entropy alloy material of this application being widely used in the aerospace field that places high demands on high-temperature resistant materials.

[0045] Table 1 Mechanical test performance data of initial samples in Example 2

[0046]

[0047] Example 3

[0048] This embodiment is another implementation method based on Embodiment 1.

[0049] This embodiment discloses a low-density AlNbTaTiZr refractory high-entropy alloy, in which the molar percentage of each element is: Al: 12-13.5%, Nb: 25.3-27%, Ta: 8.5-9.0%, Ti: 27-28%, Zr: 26.5-28%, and some other inevitable impurities.

[0050] This embodiment discloses a method for preparing the above-mentioned low-density AlNbTaTiZr refractory high entropy alloy, see Figure 1 , the specific steps include:

[0051] Step S1, preparing raw materials; weighing Al powder, Nb powder, Ta powder, Ti powder and Zr powder according to the designed molar ratio and putting them into a three-dimensional mixer for mixing, while filling with high-purity argon gas with a purity of 99.99% for protection to prevent powder oxidation, and uniformly mixing for 2 to 3 hours to obtain a mixed powder;

[0052] Step S2, preparing an alloy ingot; vacuum melting the mixed powder to obtain a block-shaped alloy ingot.

[0053] Step S3, vacuum melting the alloy ingot; vacuum melting the alloy ingot in an arc melting furnace, first evacuating the chamber of the melting furnace to level 5 vacuum, then backfilling it with argon gas with a purity of 99.99%, and using a molten titanium aspirator to remove residual oxygen in the chamber. The arc current is 400-600A, and the alloy ingot is turned over and melted 7-9 times, each time for 3-4 minutes, and electromagnetic stirring is performed to obtain a low-density AlNbTaTiZr refractory high-entropy alloy ingot with full density and high uniformity.

[0054] Step S4, heat treating the alloy ingot; heat treating the low-density AlNbTaTiZr refractory high-entropy alloy ingot obtained by vacuum melting. Exemplarily, the heat treatment equipment is a ceramic fiber box furnace, model BFX-18C. The alloy ingot is placed in the furnace and heated to 1150-1250°C, then kept warm for 24 hours under the set conditions, and then the alloy ingot is water quenched to obtain an initial sample with both high yield strength and excellent plasticity.

[0055] Step S5, heat treating the initial sample; placing the initial sample in a heat treatment device again and heating it to 550-650°C. Exemplarily, the heat treatment device is a ceramic fiber box furnace, model BFX-18C, and keeping it warm for 24 hours under the set conditions, and then water quenching to obtain a heat-treated sample with higher yield strength and certain plasticity.

[0056] The initial sample obtained in this example has a BCC single-phase structure in terms of microstructure, high-temperature structural stability, and a sample density of less than 7g / cm 3 , compressive strength is higher than 1800MPa, and it has good plasticity.

[0057] Example 4

[0058] This embodiment is another implementation method based on Embodiment 1.

[0059] This embodiment discloses a low-density AlNbTaTiZr refractory high-entropy alloy, in which the molar percentage of each element is: Al: 12%, Nb: 25.5%, Ta: 8.5%, Ti: 27.5%, Zr: 26.5%, and some other inevitable impurities.

[0060] This embodiment discloses a method for preparing the above-mentioned low-density AlNbTaTiZr refractory high entropy alloy, see Figure 1 , the specific steps include:

[0061] Step S1, preparing raw materials; weighing Al powder, Nb powder, Ta powder, Ti powder and Zr powder according to the designed molar ratio and putting them into a three-dimensional mixer for mixing, while filling with high-purity argon gas with a purity of 99.99% for protection to prevent powder oxidation, and obtaining a mixed powder after uniform mixing for 3 hours;

[0062] Step S2, preparing an alloy ingot; vacuum melting the mixed powder to obtain a block-shaped alloy ingot.

[0063] Step S3, vacuum melting the alloy ingot; vacuum melting the alloy ingot in an arc melting furnace, first evacuating the chamber of the melting furnace to level 5 vacuum, and then backfilling it with argon gas with a purity of 99.99%, using a molten titanium aspirator to remove residual oxygen in the chamber, the arc current is 400A, the alloy ingot is turned over and melted 9 times, each time lasting 4 minutes, and electromagnetic stirring is performed to obtain a low-density AlNbTaTiZr refractory high-entropy alloy ingot with full density and high uniformity.

[0064] Step S4, heat treating the alloy ingot; heat treating the low-density AlNbTaTiZr refractory high-entropy alloy ingot obtained by vacuum melting. Exemplarily, the heat treatment equipment is a ceramic fiber box furnace, model BFX-18C. The alloy ingot is placed in the furnace and heated to 1200°C, then kept at 1200°C for 24 hours, and then the alloy ingot is water quenched to obtain an initial sample with both high yield strength and excellent plasticity.

[0065] Step S5, heat treating the initial sample; placing the initial sample in a heat treatment device again and heating it to 600°C. Exemplarily, the heat treatment equipment is a ceramic fiber box furnace, model BFX-18C, and keeping it warm for 24 hours under the set conditions, and then water quenching to obtain a heat-treated sample with higher yield strength and certain plasticity.

[0066] The heat-treated sample obtained in this example has a BCC single-phase structure in terms of microstructure, high-temperature microstructure stability, and a sample density of less than 7g / cm 3 , the compressive strength is 1828MPa, and it has an excellent compression plasticity of 20%, indicating that the heat-treated sample obtained in this embodiment not only has a high yield strength and excellent compression plasticity, but also has a low density, which is conducive to meeting the dual needs of light weight and high strength in the aerospace field.

[0067] Example 5

[0068] This embodiment is another implementation method based on Embodiment 1.

[0069] This embodiment discloses a low-density AlNbTaTiZr refractory high-entropy alloy, in which the molar percentage of each element is: Al: 12%, Nb: 25.8%, Ta: 8.7%, Ti: 27%, Zr: 26.5%, and some other inevitable impurities.

[0070] This embodiment discloses a method for preparing the above-mentioned low-density AlNbTaTiZr refractory high entropy alloy, see Figure 1 , the specific steps include:

[0071] Step S1, preparing raw materials; weighing Al powder, Nb powder, Ta powder, Ti powder and Zr powder according to the designed molar ratio and putting them into a three-dimensional mixer for mixing, while filling with high-purity argon gas with a purity of 99.99% for protection to prevent powder oxidation, and obtaining a mixed powder after uniform mixing for 2.5 hours;

[0072] Step S2, preparing an alloy ingot; vacuum melting the mixed powder to obtain a block-shaped alloy ingot.

[0073] Step S3, vacuum melting the alloy ingot; vacuum melting the alloy ingot in an arc melting furnace, first evacuating the chamber of the melting furnace to level 5 vacuum, and then backfilling it with argon gas with a purity of 99.99%, using a molten titanium aspirator to remove residual oxygen in the chamber, the arc current is 500A, the alloy ingot is turned over and melted 8 times, each time lasting 3.5 minutes, and electromagnetic stirring is performed to obtain a low-density AlNbTaTiZr refractory high-entropy alloy ingot with full density and high uniformity.

[0074] Step S4, heat treating the alloy ingot; heat treating the low-density AlNbTaTiZr refractory high-entropy alloy ingot obtained by vacuum melting. Exemplarily, the heat treatment equipment is a ceramic fiber box furnace, model BFX-18C. The alloy ingot is placed in the furnace and heated to 1250°C, then kept at 1250°C for 24 hours, and then the alloy ingot is water quenched to obtain an initial sample with both high yield strength and excellent plasticity.

[0075] The initial sample obtained in this example has a BCC single-phase structure in terms of microstructure, high-temperature structural stability, and a sample density of less than 7g / cm 3 , compressive strength is higher than 1300MPa, and it has good plasticity.

[0076] Example 6

[0077] This embodiment is another implementation method based on Embodiment 1.

[0078] This embodiment discloses a low-density AlNbTaTiZr refractory high-entropy alloy, in which the molar percentage of each element is: Al: 12%, Nb: 25.8%, Ta: 8.7%, Ti: 27%, Zr: 26.5%, and some other inevitable impurities.

[0079] This embodiment discloses a method for preparing the above-mentioned low-density AlNbTaTiZr refractory high entropy alloy, see Figure 1 , the specific steps include:

[0080] Step S1, preparing raw materials; weighing Al powder, Nb powder, Ta powder, Ti powder and Zr powder according to the designed molar ratio and putting them into a three-dimensional mixer for mixing, while filling with high-purity argon gas with a purity of 99.99% for protection to prevent powder oxidation, and obtaining a mixed powder after uniform mixing for 2.5 hours;

[0081] Step S2, preparing an alloy ingot; vacuum melting the mixed powder to obtain a block-shaped alloy ingot.

[0082] Step S3, vacuum melting the alloy ingot; vacuum melting the alloy ingot in an arc melting furnace, first evacuating the chamber of the melting furnace to level 5 vacuum, and then backfilling it with argon gas with a purity of 99.99%, using a molten titanium aspirator to remove residual oxygen in the chamber, the arc current is 400A, the alloy ingot is turned over and melted 8 times, each time lasting 3.5 minutes, and electromagnetic stirring is performed to obtain a low-density AlNbTaTiZr refractory high-entropy alloy ingot with full density and high uniformity.

[0083] Step S4, heat treating the alloy ingot; heat treating the low-density AlNbTaTiZr refractory high-entropy alloy ingot obtained by vacuum melting. Exemplarily, the heat treatment equipment is a ceramic fiber box furnace, model BFX-18C. The alloy ingot is placed in the furnace and heated to 1250°C, then kept at 1250°C for 24 hours, and then the alloy ingot is water quenched to obtain an initial sample with both high yield strength and excellent plasticity.

[0084] Step S5, heat treating the initial sample; placing the initial sample in a heat treatment device again and heating it to 550°C. Exemplarily, the heat treatment equipment is a ceramic fiber box furnace, model BFX-18C, and keeping it warm for 24 hours under the set conditions, and then water quenching to obtain a heat-treated sample with higher yield strength and certain plasticity.

[0085] The initial sample obtained in this example has a BCC single-phase structure in terms of microstructure, high-temperature structural stability, and a sample density of less than 7g / cm 3 , compressive strength is higher than 1800MPa, and it has good plasticity.

[0086] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A low-density AlNbTaTiZr refractory high-entropy alloy, characterized in that: The molar percentage of each element is: Al: 12-13.5%, Nb: 25.3-27%, Ta: 8.5-9.0%, Ti: 27-28%, Zr: 26.5-28%, and some other inevitable impurities.

2. According to the low-density AlNbTaTiZr refractory high-entropy alloy according to claim 1, a method for preparing the low-density AlNbTaTiZr refractory high-entropy alloy is provided, characterized in that: The following steps are involved: Step S1, preparing raw materials and preparing mixed powder according to a designed molar ratio; Step S2, preparing an alloy ingot, vacuum melting the mixed powder to obtain an alloy ingot; Step S3: vacuum melting the alloy ingot to obtain an alloy ingot Step S4: heat-treating the alloy ingot to obtain an initial sample.

3. The method for preparing the low-density AlNbTaTiZr refractory high-entropy alloy according to claim 2, characterized in that: In the step S1, the mixed powder is put into a three-dimensional mixer for mixing, and high-purity argon gas with a purity of 99.99% is filled in for protection.

4. The method for preparing a low-density AlNbTaTiZr refractory high-entropy alloy according to claim 3, characterized in that: In the step S1, the mixing time of the mixed powder in the three-dimensional mixer is 2 to 3 hours.

5. The method for preparing a low-density AlNbTaTiZr refractory high-entropy alloy according to claim 4, characterized in that: In step S3, an arc melting furnace is used to vacuum melt the alloy ingot. The chamber of the melting furnace is first evacuated to level 5 vacuum, then backfilled with argon gas with a purity of 99.99%, and residual oxygen in the chamber is removed using a molten titanium getter.

6. The method for preparing the low-density AlNbTaTiZr refractory high-entropy alloy according to claim 5, characterized in that: In the step S3, the arc current of the vacuum melting is 400-600A.

7. The method for preparing a low-density AlNbTaTiZr refractory high-entropy alloy according to claim 6, characterized in that: In step S3, the alloy ingot is turned over and melted 7 to 9 times, each time lasting 3 to 4 minutes, and electromagnetic stirring is performed.

8. The method for preparing a low-density AlNbTaTiZr refractory high-entropy alloy according to claim 7, characterized in that: In the step S4, the alloy ingot is placed in a heat treatment furnace for heating.

9. The method for preparing a low-density AlNbTaTiZr refractory high-entropy alloy according to claim 8, characterized in that: In the step S4, the alloy ingot is heated to 1150-1250° C. in a heat treatment furnace, and then kept at the set temperature for 24 hours.

10. The method for preparing a low-density AlNbTaTiZr refractory high-entropy alloy according to claim 9, characterized in that: In the step S4, the alloy ingot after the heat preservation is cooled by water quenching.

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