High-entropy alloy resistant to corrosion of molten metal cerium as well as preparation method and application of high-entropy alloy

Abstract

The invention provides a high-entropy alloy resistant to molten metal cerium corrosion and a preparation method and application thereof, the general formula of the high-entropy alloy resistant to molten metal cerium corrosion is AlxMoNbTaWy, x is larger than or equal to 0.01 and smaller than or equal to 0.3, y is larger than or equal to 0.01 and smaller than or equal to 0.2, and x and y correspond to molar ratios of elements respectively. The preparation method of the molten metal cerium corrosion resistant high-entropy alloy comprises the following steps: weighing the raw materials Al, Ta, Nb, W and Mo according to the general formula; and after mixing, a vacuum arc melting induction furnace is adopted for vacuum melting under the inert gas atmosphere, and the high-entropy alloy resistant to molten metal cerium corrosion is obtained. The high-entropy alloy resistant to molten metal cerium corrosion has good high-temperature molten cerium corrosion resistance, is low in cost, and has good application prospects and large-scale industrial popularization potential in the field of nuclear power station metal parts.

Description

Technical Field

[0001] The invention relates to alloy technology, and in particular to a high entropy alloy resistant to corrosion by molten metal cerium, and a preparation method and application thereof. Background Art

[0002] In the Electron Beam-Physical Vapor Deposition (EB-PVD) technology, the beam plate provides a channel for the incidence of the electron beam and shapes and limits the current of the generated metal vapor. It needs to be in contact with high-temperature metal vapor for a long time, and its service environment is extremely harsh. The material of this device is required to have excellent resistance to molten metal corrosion to ensure that the device can have the necessary long service life under conditions such as high-temperature thermal cycles and strong corrosion. At present, the base material of the device is tantalum metal, but the base material is not ideal, mainly manifested in the high corrosion rate of high-temperature molten metal on tantalum metal, which cannot achieve the expected service life. Therefore, it is necessary to study materials with better corrosion resistance. Summary of the invention

[0003] The purpose of the present invention is to propose a high entropy alloy resistant to molten metal cerium corrosion, in view of the problems that existing alloys have poor high-temperature molten metal corrosion resistance and high cost. The high entropy alloy has good high-temperature molten cerium corrosion resistance and low cost, and has good application prospects and large-scale industrial promotion potential in the field of nuclear power plant metal parts.

[0004] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a high entropy alloy resistant to corrosion by molten metal cerium, whose general formula is AlxMoNbTaWy, wherein 0.01≤x≤0.3, 0.3%0.01≤y≤0.2, and x and y correspond to the molar ratios of the elements respectively.

[0006] Furthermore, the general formula of the high entropy alloy resistant to molten metal cerium corrosion is AlxMoNbTaWy, wherein 0.1≤x≤0.2, 0.01≤y≤0.1, and x and y correspond to the molar ratio of the elements respectively.

[0007] Furthermore, the high entropy alloy resistant to corrosion by molten metal cerium has a BCC disordered solid solution structure.

[0008] Furthermore, the high entropy alloy resistant to molten metal cerium corrosion has excellent high-temperature phase stability and still has a single-phase BCC structure after 1200° C. melt corrosion.

[0009] Another object of the present invention is to disclose a method for preparing a high entropy alloy resistant to corrosion by molten metal cerium, comprising the following steps: weighing raw materials Al, Ta, Nb, W and Mo according to a general formula; and performing vacuum melting in an inert gas atmosphere using a vacuum arc melting induction furnace to obtain a high entropy alloy resistant to corrosion by molten metal cerium.

[0010] Furthermore, the Al, Nb, Ta, W and Mo are all industrial grade pure raw materials with a purity greater than or equal to 99wt%. Preferably, the selected raw materials are Nb particles with a purity of 99.9wt.%, Mo particles with a purity of 99.9wt.%, Ta blocks with a purity of 99.95wt.%, W wires with a purity of 99.9wt.%, and Al particles with a purity of 99.95wt.%. More preferably, the purity of the Al, Nb, Ta, W and Ti raw materials is all above 99.9wt%.

[0011] Furthermore, when weighing the raw materials, the weighing error was ±0.001 g.

[0012] Furthermore, before vacuum melting, the surfaces of the raw materials Al, Nb, Ta, W and Mo are polished with sandpaper to remove oxide scales and stains on the surfaces of the raw materials.

[0013] Furthermore, when placing the alloy raw materials, Al and Mo raw materials are placed at the bottom, and Nb, Ta and W are placed at the top. The present invention places Al and Mo with low melting points at the bottom of the crucible, and Nb, Ta and W with high melting points at the top, to prevent the arc impact from being too large during arcing, causing small-sized metal particles to splash.

[0014] Furthermore, before the vacuum melting, the vacuum arc melting induction furnace is evacuated to 5×10 -3 Pa-3×10 - 3 Pa, and then backwash argon to 0.05-0.06MPa.

[0015] Furthermore, the vacuum melting process is assisted by electromagnetic stirring.

[0016] Furthermore, before melting the alloy ingot, the Ti ingot is first melted for 3 to 5 times, each time for 60 to 90 seconds, so as to remove excess oxygen in the chamber as much as possible.

[0017] Furthermore, when vacuum melting the alloy ingot, the current is controlled at 500-600A, and the melting is repeated 6-8 times. Each melting arc should last for 2-3 minutes to ensure that the alloy is fully melted.

[0018] Another object of the present invention is to disclose the use of a high entropy alloy resistant to corrosion by molten metal cerium in the field of key metal components of nuclear power plants.

[0019] Furthermore, the high entropy alloy resistant to corrosion by molten metal cerium is particularly suitable for a core catcher melting device of a nuclear power plant.

[0020] The high entropy alloy resistant to molten metal cerium corrosion, the preparation method and use thereof of the present invention have the following advantages compared with the prior art:

[0021] 1) The high entropy alloy resistant to molten metal cerium corrosion of the present invention selects high melting point refractory elements Mo, Ta, Nb, W and low melting point Al as main components, and adjusts the element ratio between the alloy components by phase diagram simulation calculation to obtain a series of refractory multi-principal alloys, and the alloys all maintain a single BCC disordered solid solution structure;

[0022] 2) The high entropy alloy resistant to molten metal cerium corrosion provided by the present invention, by adding high temperature resistant and refractory elements such as Ta, Nb, and W, makes the alloy corrode uniformly and reduces the melting corrosion rate of the alloy, so that the alloy has excellent high temperature melting corrosion resistance and can be used as a candidate material for high temperature structural parts. The high entropy alloy resistant to molten metal cerium corrosion of the present invention has excellent high temperature melting cerium corrosion resistance. For example, in a melting corrosion experiment at 1200°C for 50 hours, the Al 0.2 oeLh 0.01 The corrosion rate is 0.04 μm / h, which is lower than that of Al 0.1 oeLh 0.3 The corrosion rate is low, and it is expected to realize the engineering application of refractory high entropy alloys.

[0023] 3) The high entropy alloy resistant to molten metal cerium corrosion of the present invention is a cast alloy, which has excellent molten corrosion resistance in the cast state, does not require subsequent reprocessing and heat treatment steps, has a simple process flow, and reduces costs.

[0024] 4) The high entropy alloy resistant to molten metal cerium corrosion of the present invention can be widely used in key metal parts requiring high corrosion resistance in the field of nuclear power plants or in key metal parts in the aerospace field due to its excellent high-temperature molten metal corrosion resistance.

[0025] 5) The preparation method of the high entropy alloy resistant to molten metal cerium corrosion of the present invention is simple, and the preparation is performed by induction melting under an inert protective gas, and the ingot is cut into shape by wire cutting. The alloy does not require heat treatment and subsequent complex processing technology, and can have excellent high temperature molten cerium corrosion resistance.

[0026] 6) The present invention reduces the cost of high entropy alloys by adding Al, Mo, Nb, and W elements compared to the current pure Ta alloy element. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a surface SEM image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 before molten corrosion;

[0028] Figure 2 This is a surface EDS image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 before molten corrosion;

[0029] Figure 3 The XRD diffraction analysis spectrum of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 before and after the molten corrosion experiment, the molten corrosion environment is 1200°C and kept for 50 hours;

[0030] Figure 4 This is a surface SEM image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 after being corroded by molten metal cerium at 1200° C. for 50 hours;

[0031] Figure 5 This is a surface EDS image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 after being corroded by molten metal cerium at 1200° C. for 50 hours;

[0032] Figure 6 This is a cross-sectional EDS image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 after being corroded by molten metal cerium at 1200° C. for 50 hours;

[0033] Figure 7 It is a corrosion rate diagram of the high entropy alloys of Examples 1 and 2 and Comparative Example 2 after being corroded by molten metal cerium at 1200°C for 50 hours. DETAILED DESCRIPTION

[0034] The present invention is further described below with reference to the examples. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0035] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0036] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0037] In the present specification, a numerical range expressed using "above" or "below" means a numerical range including the number.

[0038] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0039] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0040] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0041] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0042] Example 1

[0043] This embodiment discloses a high entropy alloy resistant to molten metal cerium corrosion, which has the general formula of Al 0.2 oeLh 0.01 .

[0044] High entropy alloy Al resistant to molten metal cerium corrosion 0.2 oeLh 0.01 The preparation method is as follows: weigh the raw materials Ta, Al, Mo, W and Nb according to the molar ratio shown in the general formula, wherein Ta, Al, Mo, W and Nb elements are all industrial grade pure raw materials with a purity of more than 99.5wt%. Then, a vacuum arc melting induction furnace is used for melting. When the alloy is melted, the Al and Mo are placed at the bottom, and the Nb, Ta and W are placed at the top. The vacuum is evacuated to 5×10 -3 Pa, and then recoil argon to 0.06MPa. During arc melting, each alloy ingot is melted at least 7-8 times to ensure uniform composition.

[0045] Figure 1 This is a surface SEM image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 before molten corrosion. It can be seen from the image that the alloy has a small and uniform grain size and no segregation of the intracrystalline structure is found.

[0046] Figure 2 This is the surface EDS image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 before molten corrosion. It can be seen from the image that all elements are evenly distributed in the matrix without obvious segregation.

[0047] Figure 3 Example 1: BCC structure high entropy alloy Al2O3 resistant to molten metal corrosion 0.2 oeLh 0.01 The XRD diffraction analysis patterns before and after the melt corrosion experiment show that the alloy is composed of a BCC structural phase before and after the melt corrosion experiment, and no phase change or precipitation phase occurs. The molten metal corrosion-resistant high-entropy alloy of this embodiment has excellent high-temperature melt corrosion resistance stability.

[0048] Figure 4This is a surface SEM image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 after being corroded by molten metal cerium at 1200°C for 50 hours. It can be seen from the image that the corrosion surface of the alloy of the present invention is relatively smooth after molten metal corrosion, and the type of corrosion that occurs is uniform corrosion.

[0049] Figure 5 This is the surface EDS image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 after being corroded by molten metal cerium at 1200°C for 50 hours. It can be seen from the image that the various elements are evenly distributed without element segregation.

[0050] Figure 6 This is the cross-sectional EDS image of the high entropy alloy resistant to molten metal cerium corrosion in Example 1 after being corroded by molten metal cerium at 1200° C. for 50 hours. Figure 6 The element distribution of the cross section after corrosion is shown. The elements are evenly distributed after corrosion, indicating that the alloy has excellent corrosion resistance.

[0051] The alloy melt corrosion test method is as follows: First, the high entropy alloy resistant to molten metal cerium corrosion in this embodiment is cut into 3mm thick slices (15mm×8mm), double-sided fine grinding and single-sided polishing are performed. Then the sample is placed in a tantalum crucible containing 25g cerium particles, the purity of Ce is 99.9%, the outer diameter of the tantalum crucible is 35mm, the inner diameter is 30mm, the inner height is 7.5mm, and the outer height is 10mm. The prepared sample is subjected to a high temperature melt corrosion test at 1200℃ for 50h, and argon gas is continuously introduced during the insulation period.

[0052] Example 2

[0053] This embodiment discloses a high entropy alloy resistant to molten metal cerium corrosion, which has the general formula of Al 0.2 oeLh 0.1 The preparation method of the molten metal corrosion resistant high entropy alloy in this embodiment is the same as that in the first embodiment.

[0054] After testing this embodiment A1 0.2 oeLh 0.1 Same as Example 1A1 0.2 oeLh 0.01 It also has excellent resistance to molten metal corrosion and can be widely used in key metal components of nuclear power plants.

[0055] Comparative Example 1

[0056] The AlMoNbTaW high entropy alloy with an atomic ratio of 1:1:1:1:1 was prepared by the same method as in Example 1. After multiple smeltings, the alloy could not be formed normally, so the subsequent corrosion experiment could not be carried out. Analysis of the reasons: The results of phase diagram simulation calculations showed that the alloy had a wide solid-liquid two-phase region, the high melting point alloy had solidified, and the low melting point alloy was still in liquid, so it could not be well formed, proving that this method could not prepare the alloy.

[0057] Comparative Example 2

[0058] The same method as in Example 1 was used to prepare Al 0.1 oeLh 0.3 The high entropy alloy was subjected to the same corrosion test as in Example 1. The results showed that the corrosion rate of the alloy was 0.07 μm / h, which was higher than the corrosion rate of the example. The corrosion resistance of Example 1 exceeded that of Comparative Example 3.

[0059] Figure 7 This is a corrosion rate graph of the high entropy alloys of Examples 1 and 2 and Comparative Example 2 after being corroded by molten cerium at 1200°C for 50 hours. It can be seen from the graph that the corrosion rate of the examples is lower than that of the comparative examples, because the Al element can form an effective protective film during the high-temperature molten corrosion process to slow down the erosion rate of the molten metal on the alloy. The comparative example cannot form a complete protective film due to the low Al content, and therefore, the corrosion rate is higher than that of the examples.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high entropy alloy resistant to corrosion by molten metal cerium, characterized in that: The general formula thereof is AlxMoNbTaWy, wherein 0.01≤x≤0.3, 0.01≤y≤0.2, and x and y correspond to the molar ratios of the elements, respectively.

2. The high entropy alloy resistant to molten metal cerium corrosion according to claim 1, characterized in that: The general formula of the high entropy alloy resistant to molten metal cerium corrosion is AlxMoNbTaWy, wherein 0.1≤x≤0.2, 0.01≤y≤0.1, and x and y correspond to the molar ratio of the elements respectively.

3. A method for preparing a high entropy alloy resistant to molten metal cerium corrosion according to claim 1 or 2, characterized in that: The following steps are involved: Raw materials Al, Ta, Nb, W and Mo are weighed according to a general formula; vacuum melting is performed in an inert gas atmosphere in a vacuum arc melting induction furnace to obtain a high entropy alloy resistant to corrosion by molten metal cerium.

4. The method for preparing a high entropy alloy resistant to molten metal cerium corrosion according to claim 3, characterized in that: The selected raw materials are Nb particles with a purity of 99.9wt.%, Mo particles with a purity of 99.9wt.%, Ta blocks with a purity of 99.95wt.%, W wires with a purity of 99.9wt.%, and Al particles with a purity of 99.95wt.%.

5. The method for preparing a high entropy alloy resistant to molten metal cerium corrosion according to claim 3, characterized in that: When placing the alloy raw materials, Al and Mo raw materials are placed at the bottom, and Nb, Ta and W are placed on the top.

6. The method for preparing a high entropy alloy resistant to molten metal cerium corrosion according to claim 3, characterized in that: Before the vacuum melting, the vacuum arc melting induction furnace was evacuated to 5×10 -3 Pa-3×10 -3 Pa, and then backwash argon to 0.05-0.06MPa.

7. The method for preparing a high entropy alloy resistant to molten metal cerium corrosion according to claim 3, characterized in that: The vacuum melting process is assisted by electromagnetic stirring.

8. The method for preparing a high entropy alloy resistant to molten metal cerium corrosion according to claim 3, characterized in that: Before smelting the alloy ingot, smelt the Ti ingot first, smelt it 3 to 5 times, and smelt it for 60 to 90 seconds each time.

9. The method for preparing a high entropy alloy resistant to molten metal cerium corrosion according to claim 3, characterized in that: When vacuum melting alloy ingots, the current is controlled at 500-600A, and the melting is repeated 6-8 times. Each melting arc should last for 2-3 minutes.

10. Use of the high entropy alloy resistant to molten metal cerium corrosion according to claim 1 or 2 in the field of key metal parts of nuclear power plants.

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