Wide-temperature-range high-strength light eutectic high-entropy alloy and preparation method thereof

Abstract

The invention discloses a wide-temperature-range high-strength light eutectic high-entropy alloy and a preparation method thereof, belongs to the technical field of metal materials, and provides a corresponding preparation method, and the atomic percent expression of the eutectic high-entropy alloy is NiaFebAlcTidCre. The eutectic high-entropy alloy prepared by the invention not only has excellent mechanical properties at room temperature and high temperature, but also does not contain noble metal elements and refractory metal elements; the method can realize triple beneficial effects of improving the mechanical property of the eutectic high-entropy alloy, reducing the weight and reducing the cost, widens the engineering application range of the eutectic high-entropy alloy, and has a wide industrial application scene.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and in particular to a lightweight eutectic high-entropy alloy with high strength in a wide temperature range and a preparation method thereof. Background Art

[0002] Eutectic alloys are a type of alloy material obtained through liquid-solid eutectic reactions and are widely used in rail transit, aerospace, navigation and other industrial fields. Compared with other alloys, eutectic alloys have the advantages of low melting point, easy smelting and casting, good casting fluidity, fewer casting defects such as shrinkage, shrinkage, segregation, etc. However, the performance development of traditional binary or ternary eutectic alloys (such as Fe-C, Ni-Al, Al-Si, etc.) has reached its limit and it is difficult to meet the performance requirements of the current advanced manufacturing industry. The concept of eutectic high entropy alloys has been proposed in the prior art. This multi-principal component feature provides a broad space for the design of new alloys with multiple excellent properties, and also provides a new idea for solving the problem of poor casting fluidity and easy component segregation of solid solution high entropy alloys.

[0003] So far, researchers have developed a series of eutectic high entropy alloys with excellent performance, such as AlCoCrFeNi 2.1 、CrFeNi2Al、Ni 30 Co 30 Cr 10 Fe 10 Al 18 W2、AlCrFeNiCo 1.9 、CoFeNi2V 0.5 Nb 0.75 However, there are still several problems to be solved in the current eutectic high entropy alloys on the road to widespread industrial application: (1) Cast eutectic high entropy alloys generally have low plasticity and toughness, and often require a series of subsequent thermal mechanical processing, which poses a challenge to the service performance of integrated eutectic high entropy alloys; (2) Most eutectic high entropy alloys contain precious metal elements such as Co and V or refractory metal elements such as W and Nb, which increases the production and application cost and alloy density of eutectic high entropy alloys, making it difficult to meet the current requirements of sustainable development of resources; (3) Increasingly harsh service conditions (such as high temperature and low temperature) put forward higher requirements on the mechanical property design of eutectic high entropy alloys.

[0004] Based on the above problems, the development of a eutectic high-entropy alloy with excellent mechanical properties, light weight and low cost can promote its application in the field of engineering structures, which has important scientific significance and social benefits. Summary of the invention

[0005] The object of the present invention is to provide a lightweight eutectic high entropy alloy with high strength in a wide temperature range and a preparation method thereof, so as to solve the problems in the background technology.

[0006] To achieve the above object, the present invention provides a lightweight eutectic high entropy alloy with high strength in a wide temperature range. The atomic percentage expression of the eutectic high entropy alloy is Ni a Fe b Al c Ti d Cr e , among which, 47≤a≤51, 26≤b≤30, 15≤c≤19, 1≤d≤5, 1≤e≤5.

[0007] Preferably, the atomic percentage expression of the eutectic high entropy alloy is Ni 49 Fe 28 Al 17 Ti3Cr3.

[0008] The present invention also provides a method for preparing a lightweight eutectic high entropy alloy with high strength over a wide temperature range, the steps of which are as follows: S1. According to the proportion of alloying elements, the required nickel, iron, aluminum, titanium and chromium in the raw materials are proportioned for use in preparing the alloy; S2. Put the metal element in S1 into a vacuum arc furnace or a vacuum induction melting furnace, evacuate the furnace, adjust the vacuum degree, and melt and suction-cast the alloy ingot under an argon protective atmosphere.

[0009] Preferably, in S1, the purity of nickel, iron, aluminum, titanium and chromium is not less than 99.9%.

[0010] Preferably, in S2, the metal elements are placed in a vacuum arc furnace or a vacuum induction melting furnace in the order of high melting point elements on top and low melting point elements on the bottom.

[0011] Preferably, in S2, the vacuum degree is less than 5×10 -3 Pa, the gas pressure of argon is 0.01~0.08 MPa.

[0012] Preferably, in S2, the number of smelting is greater than 4 times, and electromagnetic stirring is used during the smelting process.

[0013] Preferably, a eutectic high entropy alloy is prepared by the above preparation method, and the room temperature tensile strength exceeds 1300 MPa and the uniform elongation is greater than 13%; the tensile strength at a high temperature of 973 K exceeds 600 MPa, and the elongation at break is greater than 14%; the tensile strength at a low temperature of 77 K exceeds 1250 MPa, and the uniform elongation is greater than 2%.

[0014] Therefore, the invention provides a lightweight eutectic high-entropy alloy with high strength in a wide temperature range and a preparation method thereof, which has the following beneficial effects: (1) Compared with the mechanical properties of conventional cast eutectic high entropy alloys, the eutectic high entropy alloy prepared in the present invention has excellent mechanical properties, that is, it has excellent strength and plasticity matching. In addition to excellent room temperature mechanical properties, it also has good mechanical properties at high and low temperatures. This high-strength property in a wide temperature range is suitable for a wider range of engineering applications.

[0015] (2) Currently, most eutectic high entropy alloys contain either precious metal elements such as Co and V, or refractory metal elements such as W and Nb. The eutectic high entropy alloy prepared in the present invention does not involve the above two types of elements, which can greatly reduce the use cost of eutectic high entropy alloys. At the same time, it can also reduce the density of eutectic high entropy alloys and improve specific strength, thereby playing an important role in aerospace, aviation, automobile and other fields that require lightweighting.

[0016] (3) The eutectic high entropy alloy protected in the present invention can achieve the triple beneficial effects of improved mechanical properties, lightweight and cost reduction of the eutectic high entropy alloy, broaden the engineering application scope of the eutectic high entropy alloy, and has a wide range of industrial application scenarios.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the XRD pattern of the eutectic high entropy alloy prepared in the embodiment of the present invention; Figure 2 EBSD images of the eutectic high entropy alloy prepared in the embodiment of the present invention, wherein (a) is the inverse pole image and (b) is the phase image; Figure 3 The tensile stress-strain curves of the eutectic high entropy alloy prepared in the embodiment of the present invention at room temperature and high temperature (973 K); Figure 4 This is a comparison chart of the room temperature mechanical properties of the eutectic high entropy alloy prepared in the embodiment of the present invention and other currently cast eutectic high entropy alloys. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0021] Example Preparation of Ni 49 Fe 28 Al17 Ti3Cr3, the specific steps are: S1. According to the proportion of alloy elements, nickel, iron, aluminum, titanium and chromium are mixed, and the purity of each element by mass percentage is 99.9%; S2, put the metal elements in S1 into a vacuum arc furnace in the order of high melting point elements on top and low melting point elements on the bottom, and then evacuate the furnace to adjust the vacuum degree to 5×10 -3 Pa, argon protection was adopted, the argon pressure was 0.04 MPa, and the cast eutectic high entropy alloy ingot was obtained by suction casting after uniform melting for 5 times.

[0022] The prepared eutectic high entropy alloy ingot was tested: like Figure 1 and Figure 2 As shown, Ni 49 Fe 28 Al 17 The Ti3Cr3 eutectic high entropy alloy consists of two phases (face-centered cubic FCC and body-centered cubic BCC), which are distributed alternately in lamellar layers, with the volume fractions of the FCC phase and the BCC phase being 58% and 42%, respectively.

[0023] As shown in Figure 3, Ni 49 Fe 28 Al 17 The tensile strength and uniform elongation of Ti3Cr3 eutectic high entropy alloy are 1405 MPa and 13.6% at room temperature, 1267 MPa and 2.1% at low temperature 77 K, and 617 MPa and 14.7% at high temperature 973 K.

[0024] The mechanical properties of the prepared eutectic high entropy alloy were compared with other existing cast eutectic high entropy alloys. Figure 4 As shown, the results show that Ni 49 Fe 28 Al 17 Ti3Cr3 eutectic high entropy alloy has a better strength-plasticity match.

[0025] In comparison, the Ni prepared in this example 49 Fe 28 Al 17 Ti3Cr3 eutectic high entropy alloy has excellent mechanical properties, cost advantages and lightweight characteristics.

[0026] Therefore, the present invention provides a lightweight eutectic high entropy alloy with high strength in a wide temperature range and a preparation method thereof. The prepared eutectic high entropy alloy not only has excellent mechanical properties at room temperature, low temperature and high temperature, but also does not contain precious metal elements or refractory metal elements. Moreover, it can achieve the triple beneficial effects of improved mechanical properties, lightweight and reduced cost of the eutectic high entropy alloy, broaden the engineering application scope of the eutectic high entropy alloy, and has a wide range of industrial application scenarios.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A lightweight eutectic high entropy alloy with high strength over a wide temperature range, characterized in that: The atomic percentage expression of eutectic high entropy alloy is Ni a Fe b Al c Ti d Cr e , among which, 47≤a≤51, 26≤b≤30, 15≤c≤19, 1≤d≤5, 1≤e≤5.

2. The lightweight eutectic high entropy alloy with high strength over a wide temperature range according to claim 1, characterized in that: The atomic percentage expression of the eutectic high entropy alloy is Ni 49 Fe 28 Al 17 Ti3Cr3.

3. A method for preparing a lightweight eutectic high entropy alloy with high strength over a wide temperature range as claimed in any one of claims 1 to 2, characterized in that: Here are the steps: S1. According to the proportion of alloy elements, the required nickel, iron, aluminum, titanium and chromium in the raw materials are proportioned; S2. Put the metal element in S1 into a vacuum arc furnace or a vacuum induction melting furnace, evacuate the furnace, adjust the vacuum degree, and melt and suction-cast the alloy ingot under an argon protective atmosphere.

4. The method for preparing a lightweight eutectic high entropy alloy with high strength over a wide temperature range according to claim 3, characterized in that: In the S1, the purity of nickel, iron, aluminum, titanium and chromium is not less than 99.9%.

5. The method for preparing a lightweight eutectic high entropy alloy with high strength over a wide temperature range according to claim 3, characterized in that: In S2, the metal elements are placed in a vacuum arc furnace or a vacuum induction melting furnace in the order of high melting point elements on top and low melting point elements on the bottom.

6. The method for preparing a lightweight eutectic high entropy alloy with high strength over a wide temperature range according to claim 3, characterized in that: In S2, the vacuum degree is less than 5×10 -3 Pa, the gas pressure of argon is 0.01~0.08 MPa.

7. The method for preparing a lightweight eutectic high entropy alloy with high strength over a wide temperature range according to claim 3, characterized in that: In S2, the number of smelting is greater than 4 times, and electromagnetic stirring is used during the smelting process.

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