A method for producing a raw material rod for a w-nb alloy single crystal

Abstract

This invention discloses a method for preparing raw material rods for W-Nb alloy single crystals. The method includes: 1. mixing W powder and FNb-1 powder, pressing and sintering under vacuum at high temperature to obtain W-Nb alloy sintered bars; 2. obtaining W-Nb alloy ingots after electron beam melting; 3. obtaining W-Nb alloy extruded rods through extrusion processing; 4. producing W-Nb alloy electrode rods after hot forging; 5. obtaining raw material rods for W-Nb alloy single crystals through pre-purification and grain amplification using an electron beam zone melting furnace. This invention is the first to propose a method combining electron beam melting, extrusion and forging hot processing, and electron beam zone melting to achieve alloying of the material system and removal of internal impurity elements, promote grain breakage and uniform distribution of the microstructure, further purify and promote grain growth, which is beneficial for subsequent growth to form a single crystal structure. The preparation process is simple, easy to implement, and applicable to aerospace, nuclear energy and other fields.

Description

Technical Field

[0001] This invention belongs to the field of alloy preparation technology, specifically relating to a method for preparing raw material rods for W-Nb alloy single crystals. Background Technology

[0002] Electron beam levitation melting is a classic method for preparing single-crystal materials of refractory metals and their alloys. This method requires the following for the raw material rods used in preparing alloy single crystals: 1) The total content of impurity elements in the raw material rod must be controlled below 100 ppm; 2) The raw material rod must have a uniform microstructure, free from defects such as cracks or pores; 3) When the raw material rod is a multi-element alloy, the internal microstructure should have relatively large grains to facilitate grain engulfment during single crystal growth and make it easier to form a single crystal structure; 4) The straightness of the raw material rod must not exceed 1 mm / m.

[0003] W-Nb alloy sintered rods prepared using conventional powder metallurgy methods often fail to meet the requirements for raw material rods used in electron beam levitation melting for the preparation of W-Nb alloy single crystals. For example, the total content of gaseous impurities such as oxygen, hydrogen, nitrogen, and carbon in alloy sintered rods prepared by powder metallurgy is high, and polycrystalline W-Nb alloy electrode rods contain defects such as cracks, pores, and inclusions. The internal microstructure of the rods is uneven, and the small grain size cannot meet the requirements for grain growth or engulfment during single crystal growth, easily leading to polycrystalline formation. This is highly detrimental to the subsequent electron beam levitation melting preparation of alloy single crystals.

[0004] Currently, there are no publicly available reports internationally regarding processing and preparation methods specifically for producing high-quality raw material rods for W-Nb alloy single crystals. Therefore, in order to produce W-Nb alloy single crystals that meet the requirements, there is an urgent need to develop an economical and feasible processing technology for preparing raw material rods for W-Nb alloy single crystals. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for preparing raw material rods for W-Nb alloy single crystals. This method, for the first time, proposes a combination of electron beam melting, extrusion and forging hot processing, and electron beam zone melting to prepare raw material rods for W-Nb alloy single crystals. Electron beam melting achieves alloying of the material system and removal of internal impurity elements; hot processing achieves grain fragmentation and uniform microstructure distribution; and electron beam zone melting achieves further deep purification of the material system and grain inoculation and growth, preparing for subsequent single crystal growth. This solves the problem of high impurity element content, uneven microstructure, and small grain size in existing W-Nb alloy sintered rods, which makes it difficult to prepare alloy single crystals.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a method for preparing raw material rods for W-Nb alloy single crystals, characterized in that the method includes the following steps:

[0007] Step 1: Mix W powder and FNb-1 powder in a mixer, press them into billets using a hydraulic press and a rectangular mold, and then place the billets in a vacuum sintering furnace for high-temperature vacuum sintering to obtain W-Nb alloy sintered bars.

[0008] Step 2: Place the W-Nb alloy sintered bar obtained in Step 1 into an electron beam bombardment furnace, and melt it with electron beam to produce W-Nb alloy billet. Then, turn and saw it to obtain W-Nb alloy ingot.

[0009] Step 3: Place the W-Nb alloy ingot obtained in Step 2 on an extrusion press for extrusion processing to obtain W-Nb alloy extruded bars;

[0010] Step 4: The W-Nb alloy extruded bar obtained in Step 3 is heated and straightened on an air hammer using a die to obtain a W-Nb alloy forged bar billet, and then surface-machined to produce W-Nb alloy electrode bar.

[0011] Step 5: The W-Nb alloy electrode rods obtained in Step 4 are pre-purified and grain-scaled using an electron beam zone melting furnace to prepare W-Nb alloy rods. Then, the surface is machined to prepare raw material rods for W-Nb alloy single crystals.

[0012] Unlike existing powder metallurgy methods for preparing tungsten alloy polycrystalline rods, where the heating temperature does not exceed 2300℃, impurities, especially C, N, and O, remain in the material in elemental or compound form and cannot be completely removed. Furthermore, the presence of gaps between powder particles leads to low material density and a certain proportion of internal cracks and pores. Consequently, when growing single crystals directly from polycrystalline raw material rods prepared by powder metallurgy, impurities (segregated at grain boundaries) within these defects rapidly diffuse and escape in the molten state, severely disrupting the balance between surface tension and gravity in the molten zone. This process can lead to melt collapse and failure of single crystal growth. To address this, the present invention uses electron beam melting to produce W-Nb alloy ingots from sintered W-Nb alloy strips. A high-energy-density electron beam heats the W-Nb alloy to a liquid molten state. The solubility of impurity elements in the W-Nb alloy, including C, N, O, and others, is significantly reduced at high temperatures, causing them to rapidly diffuse and escape from the melt. Simultaneously, compounds formed by tungsten, niobium, and C, N, and O decompose at high temperatures and diffuse to the melt surface, thus being removed. This achieves deep purification of the W-Nb alloy material. Furthermore, because the W-Nb alloy is first melted into a liquid state and then solidified into an ingot, the density of the W-Nb alloy ingot is significantly better than that of materials prepared by powder metallurgy, and the ingot is free of internal defects such as cracks and pores, which is extremely beneficial for subsequent single crystal growth.

[0013] Unlike existing technologies that use free forging to process tungsten alloy polycrystalline rods, which subject the material to compressive stress in one direction and tensile stress in two directions, making deformation of the poorly ductile tungsten alloy polycrystalline material extremely unfavorable and prone to uneven deformation and numerous cracks, and where the radial grain fragmentation of W-Nb alloy rods is uneven, resulting in a non-uniform fibrous structure that is not conducive to subsequent single crystal growth, this invention uses a combination of extrusion and forging to modify the microstructure of W-Nb alloy ingots. During the extrusion process, the W-Nb alloy ingot deforms under triaxial compressive stress, ensuring a fibrous microstructure after deformation, improving the machinability of the extruded rods, and obtaining a uniform deformed microstructure, which is beneficial for subsequent forging processing, thereby improving the material yield.

[0014] Unlike existing technologies that use powder metallurgy to prepare polycrystalline tungsten alloy rods with fine grains, this invention addresses the significant challenge of growing and merging these small grains to form a single crystal structure during single crystal growth. This process results in a rich subgrain network and poor single crystal quality. Instead, this invention uses an electron beam zone furnace to pre-purify and enlarge the grains of W-Nb alloy electrode rods to prepare raw material rods for W-Nb alloy single crystal growth. The high-energy-density electron beam continuously heats the polycrystalline W-Nb alloy electrode rods for an extended period. This process generates significant recrystallization potential within the rod's fibrous structure, allowing the grains to grow rapidly at 2500℃~3000℃, forming large grains and providing favorable conditions for subsequent single crystal growth. Furthermore, the high temperature causes impurities to diffuse rapidly from the interior to the surface and escape, achieving deep impurity removal and facilitating the formation of a single crystal structure during subsequent single crystal growth.

[0015] The above-mentioned method for preparing raw material rods for W-Nb alloy single crystals is characterized in that, in step one, the mass ratio of W powder to FNb-1 powder is 97:3, and the mixing time is 16h~20h; the hydraulic press is a 600-ton hydraulic press; and the vacuum degree of the vacuum high-temperature sintering is 2×10⁻⁶. -3 Pa~5×10 -3 Pa, temperature is 2000℃~2200℃, time is 10h~20h; the total mass content of gaseous impurity elements C, N, H and O and other impurity elements in the W-Nb alloy sintering strip is not greater than 500ppm.

[0016] The method for preparing raw material rods for W-Nb alloy single crystals described above is characterized in that the electron beam bombardment furnace in step two is a 300kW electron beam bombardment furnace; and the electron beam melting is performed twice. By employing two electron beam melting processes, complete alloying of the W-Nb alloy ingot is ensured and impurities are removed.

[0017] The above-mentioned method for preparing raw material rods for W-Nb alloy single crystals is characterized in that, in step three, the W-Nb alloy ingot is first heated to 1500℃~1600℃ in an induction heating furnace during extrusion processing. The blanking deformation rate of the extrusion processing is 56.2%~81.4%, and the extrusion ratio is 5.4~2.3. This invention, by controlling the extrusion processing temperature, blanking deformation rate, and extrusion ratio, performs blanking processing on the ingot, allowing the W-Nb alloy ingot with poor plastic deformation to better break its grains under triaxial compressive force and a large deformation, thus giving it a certain degree of machinability, obtaining a uniform fibrous structure, improving the deformation capacity of the W-Nb alloy extruded rod, which is beneficial for subsequent processing and helps to improve the material yield.

[0018] The method for preparing raw material rods for W-Nb alloy single crystals described above is characterized in that the total deformation rate of the heating forging in step four is 32.5%~71.4%. This invention, by controlling the total deformation rate of the heating forging, transforms the internal grain structure of the extruded rod from fibrous to equiaxed. Simultaneously, the forging deformation is slower than the extrusion deformation, which can eliminate defects and pressure generated inside the rod during extrusion deformation, and ensures uniform dimensions and improved straightness, which is beneficial for subsequent processing.

[0019] The method for preparing a raw material rod for W-Nb alloy single crystal is characterized in that the total content of impurity elements in the raw material rod for W-Nb alloy single crystal in step five does not exceed 50 ppm, the microstructure is uniform, and the grain size is 0.1 mm to 3 mm. Pre-cultivation of grains is a prerequisite for the successful preparation of subsequent single crystals. By controlling the grain size in the raw material rod for W-Nb alloy single crystals, grain aggregation during single crystal growth is facilitated, making it easier to form single crystals and ensuring the preparation of subsequent single crystal materials.

[0020] The above-mentioned method for preparing raw material rods for W-Nb alloy single crystals is characterized in that: in step two, the diameter × height of the W-Nb alloy billet is 70mm × 1000mm, and the diameter × height of the W-Nb alloy ingot is 650mm × 200mm; in step three, the diameter of the W-Nb alloy extruded rod is 28mm~43mm; in step four, the diameter of the W-Nb alloy forged rod billet is 23mm, the diameter of the W-Nb alloy electrode rod is 20mm±0.1mm, and the straightness is not greater than 1mm / m; in step five, the diameter of the W-Nb alloy rod is 23mm~25mm, the diameter of the raw material rod for W-Nb alloy single crystals is 22mm±0.1mm, and the straightness is not greater than 1mm / m.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. This invention prepares W-Nb alloy ingots by electron beam melting, which promotes the removal of impurity elements such as C, N, and O from the W-Nb alloy ingots, achieving a deep purification effect. At the same time, it improves the density and avoids defects such as internal cracks and pores in the ingots. Thus, it prepares W-Nb alloy single crystal raw material rods with high purity, good density, and no defects such as cracks and pores, which is beneficial for subsequent application in single crystal growth.

[0023] 2. This invention uses a combination of extrusion and forging to prepare W-Nb alloy electrode rods. The extrusion process yields a uniform fibrous structure, which improves the deformation capacity of the rods and facilitates subsequent forging, thereby increasing the material yield.

[0024] 3. This invention uses an electron beam zone melting furnace to prepare raw material rods for W-Nb alloy single crystals. Electron beam heating promotes the recrystallization of the fibrous structure of the rods to form large grain structures, while promoting the removal of impurity elements to achieve deep impurity removal and preservation, which is beneficial for subsequent growth to form single crystal structures.

[0025] 4. The W-Nb alloy single crystal raw material rod prepared by this invention has no defects such as cracks, pores and inclusions on its surface, straightness of no more than 1 mm / m, total impurity element content of no more than 50 ppm, uniform microstructure, grain size of 0.1 mm to 3 mm and larger grains along the axial direction, which facilitates grain engulfment during single crystal growth and makes it easier to form single crystal structure, ensuring the successful preparation of subsequent single crystals. This single crystal material is used in core components in cutting-edge fields such as aerospace and nuclear energy.

[0026] 5. The preparation process of the present invention is simple, low in cost, and easy to implement.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a physical image of the W-Nb alloy extruded bar prepared in Example 1 of the present invention.

[0029] Figure 2 This is a transverse metallographic diagram of the raw material rod for W-Nb alloy single crystal prepared in Example 1 of the present invention. Detailed Implementation

[0030] Example 1

[0031] This embodiment includes the following steps:

[0032] Step 1: Mix W powder and FNb-1 powder at a mass ratio of 97:3 in a mixer for 16 hours. Then, press the mixture into billets with a width × height × length of 16mm × 16mm × 400mm using a 600-ton hydraulic press and a rectangular mold. Finally, place the billets in a vacuum sintering furnace at a vacuum degree of 2 × 10⁻⁶. -3 Pa ~ 3.8 × 10 -3 Vacuum high-temperature sintering at 2000℃~2100℃ for 10h, followed by furnace cooling, yields W-Nb alloy sintered bars. The total mass content of gaseous impurity elements C, N, H and O, as well as other impurity elements in the W-Nb alloy sintered bars is 475ppm, as detailed in Table 1.

[0033] Step 2: Place the W-Nb alloy sintered strip obtained in Step 1 into a 300kW electron beam bombardment furnace and perform two electron beam melting processes to produce a W-Nb alloy billet with a diameter × height of 70mm × 1000mm. The vacuum degree of the electron beam melting is better than 5.0 × 10⁻⁶. -2 Pa, melting rate of 15kg / h~30kg / h, electron beam current of 3.5A~4.5A, and W-Nb alloy ingots with diameter × height of 65mm × 200mm were obtained by turning and sawing.

[0034] Step 3: The W-Nb alloy ingot obtained in Step 2 is heated to 1500℃~1600℃ in an induction heating furnace, and then extruded on a 1000-ton extrusion press. The extrusion deformation rate is 81.4%, and the extrusion ratio is 5.4, resulting in W-Nb alloy extruded bars with a diameter of 28mm±1mm. Figure 1 As shown;

[0035] Step 4: The W-Nb alloy extruded bar obtained in Step 3 is heated and straightened on an air hammer using a die. The total deformation rate of the heating and forging is 32.53%, resulting in a W-Nb alloy forging billet with a diameter of 23mm. Then, it is ground by centerless grinding to produce a W-Nb alloy electrode bar with a diameter of 20mm±0.1mm and a straightness of no more than 1mm / m.

[0036] Step 5: The W-Nb alloy electrode rod obtained in Step 4 is pre-purified and grain-scaled using an electron beam zone furnace with a vacuum degree of less than 8.0 × 10⁻⁶. -3 A W-Nb alloy rod with a diameter of 24 mm ± 1 mm was prepared by using a zone melting rate of 3 mm / min to 5 mm / min and an electron beam current of 1 A to 2 A. Then, by surface centerless grinding, a W-Nb alloy single crystal raw material rod with a diameter of 22 mm ± 0.1 mm and a straightness of no more than 1 mm / m was prepared.

[0037] Figure 2This is a transverse metallographic image of the raw material rod for W-Nb alloy single crystal prepared in this embodiment. Figure 2 It can be seen that the microstructure of the raw material rod for W-Nb alloy single crystal is uniform, and the grain size is 0.1mm~3mm. The total content of impurity elements in the raw material rod for W-Nb alloy single crystal is 40.855ppm, as shown in Table 2.

[0038] Example 2

[0039] This embodiment includes the following steps:

[0040] Step 1: Mix W powder and FNb-1 powder (mass ratio 97:3) in a mixer for 18 hours, then press them into billets with dimensions of 16mm x 16mm x 400mm using a 600-ton hydraulic press and a rectangular mold. The billets are then placed in a vacuum sintering furnace at a vacuum degree of 3.0 × 10⁻⁶. -3 Pa ~ 4.6 × 10 -3 Vacuum high-temperature sintering at 2100℃~2200℃ for 14h, followed by furnace cooling, yields W-Nb alloy sintered bars. The total mass content of gaseous impurity elements C, N, H and O, as well as other impurity elements in the W-Nb alloy sintered bars is 415ppm, as detailed in Table 1.

[0041] Step 2: Place the W-Nb alloy sintered strip obtained in Step 1 into a 300kW electron beam bombardment furnace and perform two electron beam melting processes to produce a W-Nb alloy billet with a diameter × height of 70mm × 1000mm. The vacuum degree of the electron beam melting is better than 5.0 × 10⁻⁶. -2 Pa, melting rate of 15kg / h~30kg / h, electron beam current of 3.5A~4.5A, and W-Nb alloy ingots with diameter × height of 65mm × 200mm were obtained by turning and sawing.

[0042] Step 3: The W-Nb alloy ingot obtained in Step 2 is heated to 1500℃~1600℃ in an induction heating furnace, and then extruded on a 1000-ton extrusion press. The extrusion deformation rate is 74.2% and the extrusion ratio is 3.9, resulting in W-Nb alloy extruded bars with a diameter of 33mm±1mm.

[0043] Step 4: The W-Nb alloy extruded bar obtained in Step 3 is heated and forged on an air hammer using a die and then straightened. The total deformation rate of the heating and forging is 51.42%, resulting in a W-Nb alloy forged bar blank with a diameter of 23mm. Then, it is ground by centerless grinding to produce a W-Nb alloy electrode bar with a diameter of 20mm±0.1mm and a straightness of no more than 1mm / m.

[0044] Step 5: The W-Nb alloy electrode rod obtained in Step 4 is pre-purified and grain-scaled using an electron beam zone furnace with a vacuum degree of less than 8.0 × 10⁻⁶. -3 A W-Nb alloy rod with a diameter of 24 mm ± 1 mm was prepared by melting at a zone melting rate of 3 mm / min to 5 mm / min and an electron beam current of 1 A to 2 A. Then, by centerless grinding, a W-Nb alloy single crystal raw material rod with a diameter of 22 mm ± 0.1 mm and a straightness of no more than 1 mm / m was prepared. Testing showed that the microstructure of the W-Nb alloy single crystal raw material rod was uniform, with a grain size of 0.1 mm to 3 mm. The total impurity element content in the W-Nb alloy single crystal raw material rod was 38.395 ppm, as detailed in Table 3.

[0045] Example 3

[0046] This embodiment includes the following steps:

[0047] Step 1: Mix W powder and FNb-1 powder (mass ratio 97:3) in a mixer for 20 hours, then press them into billets with dimensions of 16mm x 16mm x 400mm using a 600-ton hydraulic press and a rectangular mold. The billets are then placed in a vacuum sintering furnace at a vacuum degree of 3.0 × 10⁻⁶. -3 Pa ~ 5.0 × 10 -3 Vacuum high-temperature sintering at 2100℃~2200℃ for 18h, followed by furnace cooling, yields W-Nb alloy sintered bars. The total mass content of gaseous impurity elements C, N, H and O, as well as other impurity elements in the W-Nb alloy sintered bars is 465ppm, as detailed in Table 1.

[0048] Step 2: Place the W-Nb alloy sintered strip obtained in Step 1 into a 300kW electron beam bombardment furnace and perform two electron beam melting processes to produce a W-Nb alloy billet with a diameter × height of 70mm × 1000mm. The vacuum degree of the electron beam melting is better than 5.0 × 10⁻⁶. -2 Pa, melting rate of 15kg / h~30kg / h, electron beam current of 3.5A~4.5A, and W-Nb alloy ingots with diameter × height of 65mm × 200mm were obtained by turning and sawing.

[0049] Step 3: The W-Nb alloy ingot obtained in Step 2 is heated to 1500℃~1600℃ in an induction heating furnace, and then extruded on a 1000-ton extrusion press. The extrusion deformation rate is 65.8% and the extrusion ratio is 2.9, resulting in W-Nb alloy extruded bars with a diameter of 38mm±1mm.

[0050] Step 4: The W-Nb alloy extruded bar obtained in Step 3 is heated and straightened on an air hammer using a die. The total deformation rate of the heating and forging is 63.4%, resulting in a W-Nb alloy forging billet with a diameter of 23mm. Then, it is ground by centerless grinding to produce a W-Nb alloy electrode bar with a diameter of 20mm±0.1mm and a straightness of no more than 1mm / m.

[0051] Step 5: The W-Nb alloy electrode rod obtained in Step 4 is pre-purified and grain-scaled using an electron beam zone furnace with a vacuum degree of less than 8.0 × 10⁻⁶. -3 A W-Nb alloy rod with a diameter of 24 mm ± 1 mm was prepared by melting at a zone melting rate of 3 mm / min to 5 mm / min and an electron beam current of 1 A to 2 A. Then, by centerless grinding, a W-Nb alloy single crystal raw material rod with a diameter of 22 mm ± 0.1 mm and a straightness of no more than 1 mm / m was prepared. The microstructure of the W-Nb alloy single crystal raw material rod was found to be uniform, with a grain size of 0.1 mm to 3 mm. The total impurity element content in the W-Nb alloy single crystal raw material rod was 37.305 ppm, as detailed in Table 4.

[0052] Example 4

[0053] This embodiment includes the following steps:

[0054] Step 1: Mix W powder and FNb-1 powder (mass ratio 97:3) in a mixer for 20 hours, then press them into billets with dimensions of 16mm x 16mm x 400mm using a 600-ton hydraulic press and a rectangular mold. The billets are then placed in a vacuum sintering furnace at a vacuum degree of 3.0 × 10⁻⁶. -3 Pa ~ 5.0 × 10 -3 Vacuum high-temperature sintering at 2100℃~2200℃ for 20h, followed by furnace cooling, yields W-Nb alloy sintered bars. The total mass content of gaseous impurity elements C, N, H and O, as well as other impurity elements in the W-Nb alloy sintered bars is 465ppm, as detailed in Table 1.

[0055] Step 2: Place the W-Nb alloy sintered strip obtained in Step 1 into a 300kW electron beam bombardment furnace and perform two electron beam melting processes to produce a W-Nb alloy billet with a diameter × height of 70mm × 1000mm. The vacuum degree of the electron beam melting is better than 5.0 × 10⁻⁶. -2 Pa, melting rate of 15kg / h~30kg / h, electron beam current of 3.5A~4.5A, and W-Nb alloy ingots with diameter × height of 65mm × 200mm were obtained by turning and sawing.

[0056] Step 3: The W-Nb alloy ingot obtained in Step 2 is heated to 1500℃~1600℃ in an induction heating furnace, and then extruded on a 1000-ton extrusion press. The extrusion deformation rate is 56.2% and the extrusion ratio is 2.3, resulting in W-Nb alloy extruded bars with a diameter of 43mm±1mm.

[0057] Step 4: The W-Nb alloy extruded bar obtained in Step 3 is heated and straightened on an air hammer using a die. The total deformation rate of the heating and forging is 71.4%, resulting in a W-Nb alloy forging billet with a diameter of 23mm. Then, it is ground by centerless grinding to produce a W-Nb alloy electrode bar with a diameter of 20mm±0.1mm and a straightness of no more than 1mm / m.

[0058] Step 5: The W-Nb alloy electrode rod obtained in Step 4 is pre-purified and grain-scaled using an electron beam zone furnace with a vacuum degree of less than 8.0 × 10⁻⁶. -3 A W-Nb alloy rod with a diameter of 24 mm ± 1 mm was prepared by melting at a zone melting rate of 3 mm / min to 5 mm / min and an electron beam current of 1 A to 2 A. Then, by centerless grinding, a W-Nb alloy single crystal raw material rod with a diameter of 22 mm ± 0.1 mm and a straightness of no more than 1 mm / m was prepared. Testing showed that the microstructure of the W-Nb alloy single crystal raw material rod was uniform, with a grain size of 0.1 mm to 3 mm. The total impurity element content in the W-Nb alloy single crystal raw material rod was 38.415 ppm, as detailed in Table 5.

[0059] Table 1. Content of gaseous impurity elements in W-Nb alloy sintered strips prepared in Examples 1-4

[0060]

[0061] Table 2. Impurity element content in the raw material rods for W-Nb alloy single crystals prepared in Example 1

[0062]

[0063] In Table 2, “Matrix” represents the matrix element.

[0064] Table 3. Impurity element content in the raw material rods for W-Nb alloy single crystals prepared in Example 2

[0065]

[0066] In Table 3, “Matrix” represents the matrix element.

[0067] Table 4. Impurity element content in the raw material rods for W-Nb alloy single crystals prepared in Example 3

[0068]

[0069] In Table 4, “Matrix” represents the matrix element.

[0070] Table 5. Impurity element content in the raw material rods for W-Nb alloy single crystals prepared in Example 4

[0071]

[0072] In Table 5, “Matrix” represents the matrix element.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing raw material rods for W-Nb alloy single crystals, characterized in that, The method includes the following steps: Step 1: Mix W powder and FNb-1 powder in a mixer, press them into billets using a hydraulic press and a rectangular mold, and then place the billets in a vacuum sintering furnace for high-temperature vacuum sintering to obtain W-Nb alloy sintered bars. Step 2: Place the W-Nb alloy sintered bar obtained in Step 1 into an electron beam bombardment furnace, and melt it with electron beam to produce W-Nb alloy billet. Then, turn and saw it to obtain W-Nb alloy ingot. Step 3: Place the W-Nb alloy ingot obtained in Step 2 on an extrusion press for extrusion processing to obtain W-Nb alloy extruded bars; Step 4: The W-Nb alloy extruded bar obtained in Step 3 is heated and straightened on an air hammer using a die to obtain a W-Nb alloy forged bar billet, and then surface-machined to produce W-Nb alloy electrode bar. Step 5: The W-Nb alloy electrode rod obtained in Step 4 is pre-purified and grain-scaled using an electron beam zone melting furnace to prepare a W-Nb alloy rod. Then, the rod is surface-machined to prepare a raw material rod for W-Nb alloy single crystal. The total impurity element content in the raw material rod for W-Nb alloy single crystal does not exceed 50 ppm, the microstructure is uniform, and the grain size is 0.1 mm to 3 mm.

2. The method for preparing a raw material rod for W-Nb alloy single crystal according to claim 1, characterized in that, In step one, the mass ratio of W powder to FNb-1 powder is 97:3, and the mixing time is 16-20 hours; the hydraulic press is a 600-ton hydraulic press; the vacuum degree of the vacuum high-temperature sintering is 2 × 10⁻⁶. -3 Pa~5×10 -3 Pa, temperature is 2000℃~2200℃, time is 10h~20h; the total mass content of gaseous impurity elements C, N, H and O and other impurity elements in the W-Nb alloy sintering strip is not greater than 500ppm.

3. The method for preparing a raw material rod for W-Nb alloy single crystal according to claim 1, characterized in that, The electron beam bombardment furnace mentioned in step two is a 300kW electron beam bombardment furnace; the electron beam melting is performed twice.

4. The method for preparing a raw material rod for W-Nb alloy single crystal according to claim 1, characterized in that, In step three, the W-Nb alloy ingot is first heated to 1500℃~1600℃ in an induction heating furnace. The blanking deformation rate of the extrusion process is 56.2%~81.4%, and the extrusion ratio is 5.4~2.

3.

5. The method for preparing a raw material rod for W-Nb alloy single crystal according to claim 1, characterized in that, The total deformation rate of the heating forging described in step four is 32.5% to 71.4%.

6. The method for preparing a raw material rod for W-Nb alloy single crystal according to claim 1, characterized in that, In step two, the diameter × height of the W-Nb alloy billet is 70mm × 1000mm, and the diameter × height of the W-Nb alloy ingot is 650mm × 200mm; in step three, the diameter of the W-Nb alloy extruded bar is 28mm~43mm; in step four, the diameter of the W-Nb alloy forged bar billet is 23mm, the diameter of the W-Nb alloy electrode bar is 20mm±0.1mm, and the straightness is not greater than 1mm / m; in step five, the diameter of the W-Nb alloy bar is 23mm~25mm, the diameter of the W-Nb alloy single crystal raw material bar is 22mm±0.1mm, and the straightness is not greater than 1mm / m.

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