Method for preparing high-entropy alloys using alloy raw materials

Abstract

This invention provides a novel method for preparing a refractory, high-entropy alloy of NiCrNbMoTa using alloy raw materials. [Solution] By adjusting parameters such as welding wire structure, elemental ratio, peripheral wire diameter, and TIG welding specifications, the performance of the high-entropy alloy can be controlled, and a high-performance and stable high-entropy alloy product can be obtained.

Description

Technical Field

[0001] The present invention relates to the field of alloy adjustment, and specifically to a method for preparing a high-entropy alloy using alloy raw materials.

Background Art

[0002] With the continuous development of materials science, a new type of material, high-entropy alloy, has attracted great attention due to its unique microstructure and excellent properties. High-entropy alloys are usually composed of mixing five or more main elements in an equiatomic ratio or a near-equiatomic ratio. Due to such multi-component characteristics, high-entropy alloys have a thermodynamically high-entropy effect, bringing physical, chemical, and mechanical properties different from those of conventional alloys.

[0003] The refractory high-entropy alloy NiCrNbMoTa, which is a member of the high-entropy alloy family, has a high melting point, high strength, excellent corrosion resistance, and high-temperature stability, and thus is expected to have a wide range of applications in extreme environments such as aerospace, nuclear power, and chemical engineering. However, conventional preparation methods often have problems such as compositional inhomogeneity, complexity of the manufacturing process, and high cost, which limit the large-scale production and application of the refractory high-entropy alloy NiCrNbMoTa.

[0004] To overcome these problems, researchers have always been exploring new manufacturing technologies and methods. Among them, the overlay welding process using a cable welding wire is a promising preparation method. This method enables the rapid, efficient, and low-cost preparation of the refractory high-entropy alloy NiCrNbMoTa by twisting a high-melting-point metal wire or an alloy wire into a cable welding wire and performing an overlay welding process using advanced welding techniques (such as TIG rotary wire arc welding additive manufacturing technology).

[0005] For example, Patent Document CN115302124B describes the production of high-entropy alloys using cable welding wire with TIG rotary wire arc welding additive manufacturing technology. However, in practical applications, problems such as high energy consumption and the need for improved hardness and strength still remain. These problems can lead to unstable performance of the prepared high-entropy alloys or failure to meet specific application requirements. Therefore, further optimizing the composition design of cable welding wires and the process parameters of overlay welding to improve the preparation quality and performance of NiCrNbMoTa refractory high-entropy alloys has significant research and application value. [Overview of the project] [Problems that the invention aims to solve]

[0006] Based on the above background, the present invention provides a novel method for preparing a refractory high-entropy alloy of NiCrNbMoTa using alloy raw materials. By precisely designing the composition of the cable welding wire and optimizing the process parameters of the overlay welding, high-entropy alloys can be prepared quickly, efficiently, and at low cost, resulting in a refractory high-entropy alloy product of NiCrNbMoTa with excellent performance. [Means for solving the problem]

[0007] Specifically, the method for preparing a high-entropy alloy using the alloy raw materials of the present invention is characterized in that the high-entropy alloy is a refractory high-entropy alloy of NiCrNbMoTa, and includes the following steps.

[0008] In step 1, a high-melting-point metal wire or an alloy wire containing a high-melting-point metal is twisted together to obtain a refractory high-entropy alloy cable welding wire, wherein the high-melting-point metal is one of Ni, Cr, Nb, Mo, or Ta, the central wire of the refractory high-entropy alloy cable welding wire is a pure metal wire, and the peripheral wires are binary metal alloy wires, with one central wire and an integer multiple of 4 for the number of peripheral wires, wherein the central wire is one of pure nickel wire, pure chromium wire, pure niobium wire, or pure molybdenum wire, and the peripheral wires are binary metal alloy wires of the metal element used in the central wire and one of the other four high-melting-point metals, with the number of peripheral wires of different metal elements being the same.

[0009] In step 2, the refractory high-entropy alloy cable welding wire from step 1 is subjected to build-up welding to obtain a refractory high-entropy alloy of NiCrNbMoTa.

[0010] Preferably, in the peripheral wire, the molar ratio of the same metal element in the peripheral wire as in the central wire is 3% or more.

[0011] Preferably, in the peripheral wire, the molar ratio of the same metal element in the peripheral wire as in the central wire is 7% or less.

[0012] Preferably, the diameter of the central wire is 0.1 to 0.2 mm, and the diameter of the peripheral wire is 0.5 to 0.75 mm.

[0013] Preferably, the number of peripheral wires in step 1 is 4 or 8.

[0014] Preferably, the build-up welding technique utilizes TIG rotary wire arc welding additive manufacturing technology.

[0015] Preferably, cladding is additively fabricated onto the substrate using TIG rotary wire arc welding additive manufacturing technology with a refractory, high-entropy alloy cable welding wire.

[0016] Preferably, step 2 further includes feeding a refractory, high-entropy alloy cable welding wire into a wire feeder, setting the wire feed angle, wire feed speed, and additive manufacturing speed, and using pure argon gas for protection.

[0017] Preferably, the wire feeding angle is 17-25°, the wire feeding speed is 5-10 mm / s, the additive manufacturing speed is 150-200 mm / min, the welding current is 85-110 A, and the arc rotation speed is 200-250 r / min.

[0018] The NiCrNbMoTa refractory high-entropy alloy of the present invention is prepared by the method described above. [Effects of the Invention]

[0019] Compared to conventional technologies, this cable welding wire allows for easy adjustment of the mixing ratio of each metal element. By controlling the metal type of the central wire and the mixing ratio of the central element in the surrounding wire, the mixing ratio of different metal elements in the high-entropy alloy can be easily adjusted.

[0020] The hardness and strength of high-entropy alloys can be adjusted by controlling the diameter of the surrounding wire, the wire feeding angle during the TIG welding process, and other factors.

[0021] Furthermore, the method of the present invention enables additive manufacturing using relatively low welding currents. [Modes for carrying out the invention]

[0022] Example 1 Example 1: The specific procedure for preparing a refractory, high-entropy alloy of NiCrNbMoTa using alloy raw materials is as follows.

[0023] Step 1: Preparation of fire-resistant, high-entropy alloy cable welding wire Material selection and dimensions: Selection of central wire: One pure nickel wire with a diameter of 0.2 mm was selected as the central wire. Selection of peripheral wires: As the peripheral wires, four types of binary metal alloy wires, namely nickel-chromium alloy wire, nickel-niobium alloy wire, nickel-molybdenum alloy wire, and nickel-tantalum alloy wire, were selected. One alloy wire was used for each, making a total of four peripheral wires. The nickel content of each alloy wire was 3% in molar ratio, and the diameter of each was 0.6 mm.

[0024] Twisting process: The central wire and the four peripheral wires were twisted in the central-peripheral direction so that the central wire was located at the center and the peripheral wires were evenly arranged around the central wire, thereby forming a cable-like structure. In the twisting process, the wires were made to adhere closely to each other without loosening or displacement.

[0025] Step 2: Surfacing welding treatment Preparation of equipment: Using the TIG (tungsten inert gas) rotating wire arc welding additive manufacturing technology, a TIG welding machine, a wire feeding device, an argon gas protection device, etc. were prepared.

[0026] Setting of parameters: [[ID=1�]] The cable welding wire of the high-temperature-entropy alloy with high fire resistance was placed in the wire feeding device, and the wire feeding angle was adjusted to 25°, the wire feeding speed was adjusted to 10 mm / s, and the additive manufacturing speed was adjusted to 200 mm / min. The welding current was set to 85 A, and the arc rotation speed was set to 200 r / min. Protection was carried out using pure argon gas.

[0027] Work of surfacing welding: The base material (for example, a stainless steel plate) was placed on the welding table, the TIG welding machine was started, and surfacing welding was carried out according to the set parameters.

[0028] The wire feeding device fed the cable welding wire of the high-temperature-entropy alloy with high fire resistance into the welding area, the arc rotated, melting the wire and the surface of the base material to form a molten pool. As the wire was continuously fed and the base material was additively manufactured, a high-temperature-entropy alloy layer of NiCrNbMoTa was gradually formed on the base material.

[0029] Post-processing: After the build-up welding was completed, the welded area was cooled to remove residual stress and improve the structural properties. Necessary polishing and cleaning were performed to remove spatter and oxides generated during the welding process.

[0030] Example 2 Compared to Example 1, the difference is that the molar ratio of nickel in the alloy wire in Step 1 is 5% in both cases.

[0031] Example 3 Compared to Example 1, the difference is that the molar ratio of nickel in the alloy wire in Step 1 is 7% in both cases.

[0032] Comparative Example 1 Compared to Example 1, the difference is that the molar ratio of nickel in the alloy wire in Step 1 is 2% in both cases.

[0033] Comparative Example 2 Compared to Example 1, the difference is that the molar ratio of nickel in the alloy wire in Step 1 is 8% in both cases.

[0034] Example 4 In comparison with Example 2, the difference in step 1 is that the central wire uses chromium, the four surrounding wires use an alloy of chromium and four other elements, and the molar ratio of chromium in each alloy wire is 5%.

[0035] Example 5 In comparison with Example 2, the difference in step 1 is that the central wire uses niobium, the four surrounding wires use an alloy of niobium and four other elements, and the molar ratio of niobium in each alloy wire is 5%.

[0036] Example 6 In comparison with Example 2, the difference in step 1 is that the central wire uses molybdenum, the four surrounding wires use an alloy of molybdenum and four other elements, and the molar ratio of molybdenum in each alloy wire is 5%.

[0037] Comparative Example 3 In comparison with Example 2, in Step 1, the central wire was made of tantalum. The four peripheral wires were made of an alloy of tantalum and four other elements, and the difference was that the molar ratio of tantalum in each alloy wire was 5%.

[0038] Example 7 Compared to Example 5, the difference is that the molar ratio of niobium in the alloy wire in Step 1 is 6% in both cases.

[0039] Example 8 Compared to Example 5, the difference is that the molar ratio of niobium in the alloy wire in Step 1 is 7% in both cases.

[0040] Example 9 Compared to Example 5, the difference is that the diameter of the alloy wire in step 1 is 0.5 mm.

[0041] Example 10 Compared to Example 5, the difference is that the diameter of the alloy wire in step 1 is 0.75 mm.

[0042] Comparative Example 4 Compared to Example 5, the difference is that the diameter of the alloy wire in step 1 is 0.9 mm.

[0043] Example 11 Compared to Example 5, the difference is that the wire feeding angle in step 2 is 20°.

[0044] Example 12 Compared to Example 5, the difference is that the wire feeding angle in step 2 is 17°.

[0045] Comparative Example 5 Compared to Example 5, the difference is that the wire feeding angle in step 2 is 14°.

[0046] Comparative Example 6 Compared to Example 5, the difference is that the wire feeding angle in step 2 is 28°.

[0047] The micro-Vickers hardness, yield strength, and thermal stability of the high-entropy alloys obtained in the above examples and comparative examples were measured.

[0048] [Table 1]

[0049] The proportion of the central element in the peripheral alloy wire in this application has a significant effect on the Vickers hardness and yield strength. Within a certain range, as the molar ratio of the central element increases (e.g., Examples 1-3, 5, 7-8), both hardness and strength increase and remain at a high level. If the molar ratio of the central element is too low (e.g., Comparative Example 1), the hardness of the material can be maintained at a high level, but the yield strength and fracture strain decrease significantly. If the molar ratio of the central element is too high (e.g., Comparative Example 2), the fracture strain of the material still remains at a high level, but both the yield strength and Vickers hardness decrease significantly.

[0050] The technical solution of this application allows for easy replacement of the central wire element, thereby enabling significant adjustment of the molar ratio of different metal elements. Simultaneously, different elements selected for the central wire exhibit different properties in terms of hardness, yield strength, and fracture strain. According to the characterization results, when a high-melting-point metal element is used as the central wire, the resulting final alloy shows varying degrees of improvement in parameters such as hardness, yield strength, and fracture strain. When tantalum was used as the central wire element (Comparative Example 3), while no significant change in hardness was observed, the fracture strain was found to be remarkably reduced.

[0051] The diameter of the outer alloy wire in the present invention has a certain effect on the yield strength and fracture strain of the metal. The diameter of the outer wire needs to be controlled within a certain range; if the diameter is too large (for example, Comparative Example 4), the yield strength and fracture strain are clearly reduced.

[0052] The wire feed angle in the additive manufacturing process of the present invention is also a crucial parameter. By reducing the wire feed angle to a certain range, the strength of the material can be increased. However, if the wire feed angle is too small (for example, Comparative Example 5), the hardness of the material decreases sharply. If the wire feed angle is too large (for example, Comparative Example 6), the yield strength and fracture strain of the material decrease significantly.

Claims

1. A method for preparing a high-entropy alloy using alloy raw materials, wherein the high-entropy alloy is a refractory high-entropy alloy of NiCrNbMoTa. Step 1 involves twisting together high-melting-point metal wires or alloy wires containing high-melting-point metals to obtain a refractory high-entropy alloy cable welding wire, wherein the high-melting-point metal is one of Ni, Cr, Nb, Mo, or Ta, the central wire of the refractory high-entropy alloy cable welding wire is a pure metal wire, the peripheral wires are binary metal alloy wires, there is one central wire, the number of peripheral wires is an integer multiple of 4, the central wire is one of pure nickel wire, pure chromium wire, pure niobium wire, or pure molybdenum wire, the peripheral wires are binary metal alloy wires of the metal element used in the central wire and four other high-melting-point metals, and the number of peripheral wires made of different metal elements is the same. Step 2 involves applying build-up welding to the refractory high-entropy alloy cable welding wire in Step 1 to obtain a refractory high-entropy alloy of NiCrNbMoTa. A method for preparing a high-entropy alloy using alloy raw materials, characterized by containing [a specific element].

2. A method for preparing a high-entropy alloy using alloy raw materials according to claim 1, characterized in that the molar ratio of the same metal element in the peripheral wire as in the central wire is 3% or more.

3. A method for preparing a high-entropy alloy using alloy raw materials according to claim 2, characterized in that the molar ratio of the same metal element in the peripheral wire as in the central wire is 7% or less.

4. A method for preparing a high-entropy alloy using alloy raw materials according to claim 1, characterized in that the diameter of the central wire is 0.1 to 0.2 mm and the diameter of the peripheral wire is 0.5 to 0.75 mm.

5. A method for preparing a high-entropy alloy using alloy raw materials according to claim 1, characterized in that the number of peripheral wires in step 1 is four or eight.

6. A method for preparing a high-entropy alloy using alloy raw materials according to claim 1, characterized in that the build-up welding technique utilizes TIG rotary wire arc welding additive manufacturing technology.

7. A method for preparing a high-entropy alloy using alloy raw materials according to claim 6, characterized by performing cladding additive manufacturing on a substrate using a cable welding wire of a refractory high-entropy alloy by TIG rotary wire arc welding additive manufacturing technology.

8. Step 2 further includes placing a refractory high-entropy alloy cable welding wire into a wire feeding device, setting the wire feeding angle, wire feeding speed, and additive manufacturing speed, and using pure argon gas for protection, characterized in that it is a method for preparing a high-entropy alloy using alloy raw materials according to claim 7.

9. A method for preparing a high-entropy alloy using alloy raw materials according to claim 8, characterized in that the wire feeding angle is 17 to 25°, the wire feeding speed is 5 to 10 mm / s, the additive manufacturing speed is 150 to 200 mm / min, the welding current is 85 to 110 A, and the arc rotation speed is 200 to 250 r / min.

10. A refractory, high-entropy alloy of NiCrNbMoTa prepared by the method of any one of claims 1 to 9.

Images