Lightweight high-strength multi-principal-element intermetallic compound, preparation method and application thereof

Abstract

The application discloses a lightweight high-strength multi-principal-element intermetallic compound and a preparation method and application thereof. The intermetallic compound comprises Ti, Nb, V and Al, and according to 100% of atomic percentage, Ti is 45-60%, Nb is 15-20%, V is 15-25%, and Al is 15-25%, wherein the atomic percentage of V and Al is equal. The multi-principal-element intermetallic compound prepared by the application has low density, high strength and hardness, and certain plasticity, and is expected to have important application in extreme environment fields such as advanced weapon equipment and aerospace engines (such as high-temperature blades, supersonic aircraft and the like).

Description

[0001] This application claims priority to the prior application with the patent application number 2023112633748, filed on September 27, 2023, with the State Intellectual Property Office of China, and entitled “A lightweight high-strength high-entropy intermetallic compound and its preparation method and application”. The entire contents of the prior application are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application belongs to the field of metal materials, and relates to an intermetallic compound and its preparation method and application, in particular to a lightweight high-strength multi-principal-element intermetallic compound and its preparation method and application. BACKGROUND

[0003] With the continuous improvement of technology and the increasing demand for high-performance metal materials in domestic economic construction, traditional single-principal-element alloys have been unable to meet people's demand for material performance. Multi-principal-element alloys break through the limitations of traditional alloy compositions, greatly expand the composition design range of metal materials by adjusting the arrangement and content of multiple components, and exhibit excellent performance different from traditional alloys. Multi-principal-element alloys, due to their unique physical, chemical, and mechanical properties, are expected to play an important role in major engineering fields such as national defense, aviation, aerospace, ocean, nuclear energy, medical treatment, and new energy, and have great application prospects in extreme environments such as high temperature, high pressure, and high strain rate.

[0004] Lightweight intermetallic compounds are important structural materials with high specific strength and low energy consumption, and are key materials in high-end weapon equipment and energy-saving and emission-reduction engineering, which are of great significance to the upgrading of major equipment and the realization of the double carbon goal. Ti-based intermetallic compounds, due to their low density, high specific strength and specific modulus, good oxidation resistance, and excellent fatigue resistance, have become an important lightweight high-temperature structural material, and have important applications in the aerospace industry, weapon equipment, and automotive industries. However, with the continuous improvement of technology, higher requirements are put forward for the service temperature range and comprehensive mechanical properties of high-temperature materials. Therefore, it is necessary to develop a new type of intermetallic compound with low density and high strength to replace some high-temperature alloys and ceramic parts, which can meet the service performance requirements and oxidation resistance in extreme environments such as high temperature, high pressure, and high strain rate. SUMMARY

[0005] In order to improve the above technical problems, the present application provides a multi-principal-element intermetallic compound, which has the advantages of lightweight, high strength, high entropy, and is expected to have important applications in extreme environments such as weapon equipment (especially advanced weapon equipment) and aerospace engine fields (such as high-temperature blades, supersonic aircraft, etc.).

[0006] Specifically, the present application provides the following technical solutions:

[0007] A multi-principal element intermetallic compound comprising Ti, Nb, V and Al, comprising Ti 45-60%, Nb 15-20%, V 15-25%, Al 15-25% in atomic percentage of 100%, wherein the atomic percentage of V and Al is equal.

[0008] According to an embodiment of the present application, the atomic ratio of Ti and Nb is 3.

[0009] According to an embodiment of the present application, the multi-principal element intermetallic compound comprises Ti 45-54%, Nb 15-18%, V 15-20%, Al 15-20% in atomic percentage of 100%, wherein the atomic percentage of V and Al is equal. Preferably, the atomic ratio of Ti and Nb is 3.

[0010] According to an embodiment of the present application, the multi-principal element intermetallic compound can further comprise Zr, in particular, the atomic percentage of Zr is 0-5%, preferably 2-4%.

[0011] According to an embodiment of the present application, the multi-principal element intermetallic compound consists of Ti, Nb, V and Al. Further, Ti is 45-60%, Nb is 15-20%, V is 15-25%, Al is 15-25% in atomic percentage of 100%, wherein the atomic percentage of V and Al is equal. In particular, the atomic ratio of Ti and Nb is 3.

[0012] According to an embodiment of the present application, the multi-principal element intermetallic compound consists of Ti, Nb, V, Al and Zr. Further, Ti is 45-60%, Nb is 15-20%, V is 15-25%, Al is 15-25%, Zr is 0-5% in atomic percentage of 100%, wherein the atomic percentage of V and Al is equal. In particular, the atomic ratio of Ti and Nb is 3.

[0013] According to an embodiment of the present application, the atomic percentage of Ti is for example 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%.

[0014] According to an embodiment of the present application, the atomic percentage of Nb is for example 15%, 16%, 17%, 18%.

[0015] According to an embodiment of the present application, the atomic percentage of V is for example 15%, 16%, 17%, 18%, 19%, 20%.

[0016] According to an embodiment of the present application, the atomic percentage of Al is, for example, 15%, 16%, 17%, 18%, 19%, 20%.

[0017] According to an embodiment of the present application, the atomic percentage of Zr is, for example, 2%, 2.5%, 3%, 3.5%, 4%.

[0018] According to an embodiment of the present application, the multi-principal element intermetallic compound is composed of a single intermetallic compound phase. Specifically, the intermetallic compound is composed of a single B2 phase intermetallic compound. More specifically, the crystal structure of the intermetallic compound belongs to ordered body-centered cubic.

[0019] According to an embodiment of the present application, the Vickers hardness of the multi-principal element intermetallic compound is 4.0-6.0 GPa.

[0020] According to an embodiment of the present application, the density of the multi-principal element intermetallic compound is 5.0-5.6 x 10 3 kg.m -3 .

[0021] According to an embodiment of the present application, the yield strength of the multi-principal element intermetallic compound is 770-1100 MPa.

[0022] According to an embodiment of the present application, the multi-principal element intermetallic compound has an elongation of 6% and a reduction of area of 18% at a low strain rate (for example, at a strain rate of 10 -4 -10 -2 s -1 .

[0023] According to an embodiment of the present application, the microstructure of the multi-principal element intermetallic compound is uniform, and each element is uniformly distributed without segregation at grain boundaries.

[0024] The present application also provides a method for preparing the above multi-principal element intermetallic compound, which comprises:

[0025] mixing Ti, Nb, V, Al and optionally added or not added Zr according to the above atomic percentages, and using vacuum arc melting to prepare the multi-principal element intermetallic compound.

[0026] According to an embodiment of the present application, Ti, Nb, V and Al are all high-purity metals.

[0027] According to an embodiment of the present application, Zr is a high-purity metal.

[0028] According to an embodiment of the present application, the melting is performed in a vacuum arc furnace.

[0029] According to an embodiment of the present application, the pressure of the melting is 0.5-1 atm.

[0030] According to an embodiment of the present application, the melting heating current is 100-300 A, preferably 150-250 A, and the heating voltage is 10-30 V, preferably 15-25 V.

[0031] According to an embodiment of the present application, the heating temperature of the melting is 3000-3500 K.

[0032] According to an embodiment of the present application, the time of the melting is 5-30 min, preferably 5-15 min, according to the total mass of the sample.

[0033] According to an embodiment of the present application, the method is carried out under an inert atmosphere, such as a nitrogen atmosphere or an argon atmosphere.

[0034] In the present application, the melting needs to be repeated for 3-5 times to ensure the sufficient mixing of the elements inside the sample and the uniformity of the distribution thereof. Preferably, the sample mass during the melting is 10-300 g, and the heating time is 5-15 min each time, and the alloy liquid state maintaining time is not less than 5-8 min.

[0035] As an exemplary technical solution of the present application, the preparation method of the multi-principal-element intermetallic compound comprises the following steps:

[0036] a) mixing high-purity metals Ti, Nb, V and Al according to the above-mentioned atomic percentage ratio;

[0037] b) placing the above-mentioned proportionally mixed metals into a vacuum arc furnace, vacuumizing (for example, to 1.0×10 -3 Pa) through a front-stage mechanical pump and a molecular pump, then back-filling high-purity argon (for example, to 1 atm), and repeating the above-mentioned vacuumizing and argon back-filling processes at least once (for example, 1 time, 2 times, 3 times or more);

[0038] c) carrying out high-temperature arc melting under the protection of a high-purity argon atmosphere, and after the melting product is naturally cooled (for example, a button-shaped product), turning over the obtained product, and repeating the high-temperature arc melting process at least 3 times (for example, 3-5 times) to obtain the multi-principal-element intermetallic compound.

[0039] In step c) of the present application, the high-temperature arc melting process is repeated to ensure the sufficient mixing of the elements inside the product and the uniformity of the distribution thereof.

[0040] According to the embodiment of the present application, the multi-principal intermetallic compound prepared by the method consists of a single B2 phase intermetallic compound, and the crystal structure belongs to ordered body-centered cubic. The microhardness is 4.0-6.0 GPa. In particular, the density of the multi-principal intermetallic compound is 5.0-5.6 x 10 3 kg.m -3

[0041] The present application also provides the application of the above multi-principal intermetallic compound in the fields of weapon equipment (especially advanced weapon equipment) and aerospace engine, such as high-temperature blades, supersonic aircraft, etc.

[0042] The present application has the following beneficial effects:

[0043] The present application provides a multi-principal intermetallic compound with light weight, high strength, etc. In particular, the present application provides a multi-principal intermetallic compound mainly in B2 phase, which has low density, high strength and hardness, and certain plasticity, and is expected to have important application in extreme environment fields such as weapon equipment (especially advanced weapon equipment) and aerospace engine (such as high-temperature blades, supersonic aircraft, etc.).

[0044] In addition, the present application also provides a method for preparing the multi-principal intermetallic compound. In particular, the present application uses a vacuum arc furnace to directly high-temperature smelt the multi-principal intermetallic compound by mixing Ti, Nb, V and Al, and optionally adding 0-5% Zr in a proportion under the protection of high-purity argon atmosphere. The method is simple in process, and the prepared multi-principal intermetallic compound has the above-mentioned many advantages.

[0045] Further, the present application can further improve the strength of the alloy by 10-20% by adding an appropriate amount of Zr element in the multi-principal intermetallic compound, but is not conducive to the improvement of plasticity. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is the XRD pattern of the intermetallic compound in Example 1;

[0047] Figure 2 is the microstructure diagram of the intermetallic compound in Example 1;

[0048] Figure 3 is the compression stress-strain curve diagram (a) and the tensile stress-strain curve diagram (b) of the intermetallic compound in Example 1. DETAILED DESCRIPTION

[0049] ​The technical solutions of the present application will be further described in detail below in connection with specific embodiments. It should be understood that the following embodiments are only illustratively described and explained, and should not be interpreted as limiting the scope of protection of the present application. Any technology realized based on the above description of the present application is covered within the scope intended to be protected by the present application.

[0050] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0051] Example 1

[0052] The TiNbVAl intermetallic compound of the present embodiment is prepared by a preparation method comprising the following steps:

[0053] a) high-purity metals Ti, Nb, V and Al are mixed in the proportion of atomic percentage (specifically, Ti: 48%, Nb: 16%, V: 18%, Al: 18%) and prepared into a metal sample with a total mass of 30g;

[0054] b) the above proportionally mixed metals are placed in a vacuum arc furnace, vacuumed through a front-stage mechanical pump and a molecular pump to 10 -3 Pa, then high-purity argon is backfilled to one atmosphere, and the above vacuuming and argon backfilling process is repeated 1-2 times;

[0055] c) high-temperature arc melting is carried out under the protection of high-purity argon atmosphere, with the following specific parameters: atmospheric pressure of 0.5 atmospheres, heating current of 150A, heating voltage of 15V, minimum heating temperature of 3000K, liquid retention time of 5 minutes, and the button sample is obtained after natural cooling of the sample, the obtained sample is turned over, and the high-temperature arc melting process is repeated 3-5 times to ensure that the elements in the sample are fully mixed and uniformly distributed.

[0056] The multi-principal element alloy prepared in Example 1 is composed of a single B2 phase intermetallic compound phase, and the XRD analysis diagram of the phase composition is as shown in Figure 1 The solidification structure is a coarse single-phase dendrite, as shown in Figure 2 . Figure 3 are the compression stress-strain curve (a) and the tensile stress-strain curve (b) of the intermetallic compound in Example 1. As shown in Figure 3 , under the condition of a strain rate of 10 -4 ~ 10 -2 s -1 , the static yield strength is 750-950MPa, the tensile strength is 700-780MPa, the elongation is 1-6%, and the reduction of area is 6-18%.

[0057] The density of the multi-principal element alloy is 5.50-5.55×10 3 kg.m -3 , and the Vickers hardness is 4.5 GPa.

[0058] Example 2

[0059] The TiNbVAlZr intermetallic compound of the present embodiment is prepared by a preparation method comprising the following steps:

[0060] a) high-purity metals Ti, Nb, V, Al and Zr are mixed in the proportion of atomic percentage (specifically, Ti: 45%, Nb: 15%, V: 18%, Al: 18%, Zr: 4%), and prepared into a metal sample with a total mass of 100 g;

[0061] b) the above proportionally mixed metals are placed in a vacuum arc furnace, vacuumed to 10 -3 Pa through a front-stage mechanical pump and a molecular pump, then high-purity argon is backfilled to one atmosphere, and the above vacuuming and argon backfilling process is repeated 1-2 times;

[0062] c) high-temperature arc melting is carried out under the protection of high-purity argon atmosphere, and the specific parameters are set as follows: the atmosphere pressure is 0.5 atmosphere, the heating current is 200 A, the heating voltage is 20 V, the highest heating temperature is 3300 K, the liquid state retention time is 8 minutes, and the button sample is obtained after the sample is naturally cooled, the obtained sample is turned over, and the high-temperature arc melting process is repeated 3-5 times to ensure that the elements in the sample are fully mixed and uniformly distributed.

[0063] The multi-principal element alloy prepared in Example 2 has similar organizational characteristics as Example 1, and the hardness and strength are both improved by 10-20%, the Vickers hardness is about 5.2 GPa, and the static yield strength is 900-1100 MPa.

[0064] The density of the multi-principal element alloy is 5.55-5.60×10 3 kg.m -3 .

[0065] The above has exemplarily described the embodiments of the present application. However, the protection scope of the present application is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-principal intermetallic compound, characterized in that, The multi-principal intermetallic compound includes Ti, Nb, V and Al, and based on an atomic percentage of 100%, it includes 45-60% Ti, 15-20% Nb, 15-25% V and 15-25% Al, wherein the atomic percentages of V and Al are equal.

2. The multi-principal intermetallic compound according to claim 1, characterized in that, The atomic ratio of Ti to Nb is 3.

3. The multi-principal intermetallic compound according to claim 1, characterized in that, The multi-principal intermetallic compound further includes Zr; The atomic percentage of Zr is greater than 0 and less than or equal to 5%.

4. The multi-principal intermetallic compound according to claim 3, characterized in that, The atomic percentage of Zr is 2-4%.

5. The multi-principal intermetallic compound according to claim 3, characterized in that, The atomic ratio of Ti to Nb is 3.

6. The multi-principal intermetallic compound according to claim 1, characterized in that, The multi-principal intermetallic compound is composed of a single intermetallic compound phase.

7. The multi-principal intermetallic compound according to claim 6, characterized in that, The multi-principal intermetallic compound is composed of a single B2 phase intermetallic compound.

8. The multi-principal intermetallic compound according to claim 6 or 7, characterized in that, The crystal structure of the multi-principal intermetallic compound is ordered body-centered cubic.

9. The multi-principal intermetallic compound according to claim 1, characterized in that, The intermetallic compound has at least one of the following properties: 1) Vickers hardness is 4.0~6.0 GPa; 2) Density is 5.0~5.6×10 3 kg.m -3 ; 3) Yield strength is 770~1100 MPa; 4) In 10 -4 ~10 -2 s -1 Under certain strain rate conditions, the elongation can reach 6% and the reduction of area can reach 18%.

10. A method for preparing a multi-principal intermetallic compound according to any one of claims 1-9, characterized in that, The method includes: Ti, Nb, V, Al, and optional Zr were mixed in the above atomic percentages and then melted using vacuum arc melting to prepare a multi-principal intermetallic compound.

11. The method according to claim 10, characterized in that, The smelting pressure is 0.5-1 atmosphere.

12. The method according to claim 11, characterized in that, The melting heating current is 100-300A and the heating voltage is 10-30V.

13. The method according to claim 11, characterized in that, The heating temperature for the smelting is 3000-3500K.

14. The method according to claim 11, characterized in that, The melting time is 5-30 minutes.

15. The application of the multi-principal intermetallic compound according to any one of claims 1-9 in the fields of weaponry and aerospace engines.

16. The application according to claim 15, characterized in that, Used in high-temperature blades or supersonic aircraft.

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