High-homogeneity nickel-carbon intermediate alloy for aerospace high-temperature alloy and low-cost preparation method of high-homogeneity nickel-carbon intermediate alloy

Abstract

The invention discloses a high-homogeneity nickel-carbon intermediate alloy for aerospace-grade high-temperature alloys, the nickel-carbon intermediate alloy comprises the following elements in percentage by mass: 0.5-3.0% of C, and the balance of Ni and inevitable impurities, in addition, the invention also discloses a preparation method of the nickel-carbon intermediate alloy, and the preparation method comprises the following steps: 1, selecting nickel protoxide powder and carbon powder as raw materials; 2, drying the raw materials; 3, uniformly mixing the dried raw materials; 4, carbon thermal reduction-electromagnetic stirring; and 5, carrying out vacuum hot pressed sintering to obtain the high-homogeneity nickel-carbon intermediate alloy. The nickel-carbon intermediate alloy which is uniform in component, high in cleanliness and low in content of harmful gas elements and inclusions is obtained by keeping the vacuum degree in the high-pressure sintering process, ensuring sintering and forming in a high-temperature and high-pressure state, controlling sintering process parameters, reducing impurity introduction in the sintering process and meanwhile ensuring timely circulation of reaction gas; the method is suitable for the downstream high-temperature alloy field.

Description

Technical Field

[0001] This invention belongs to the field of alloy preparation technology, specifically relating to a high-homogeneity nickel-carbon master alloy for aerospace-grade high-temperature alloys and its low-cost preparation method. Background Technology

[0002] The global market demand for aero engines is booming, reaching $453 billion by 2025. The domestically produced C919 is expected to reach 2,000 units within the next 20 years, and the Chinese Air Force will add 3,000 fighter jets and 400 large military aircraft. The Chinese Navy will add 30 destroyers and frigates and 30 small and medium-sized vessels annually, resulting in a cumulative demand of 330,000 tons of high-temperature alloys. High-temperature alloys are mainly used in the hot-end components of aero-engines and are considered key core materials. Nickel-based wrought high-temperature alloys used in aero-engine combustion chambers generally suffer from poor high-temperature strength and thermal fatigue. Therefore, controlling the carbon content is crucial in the design of high-temperature alloys. However, carbon powder is difficult to add directly to molten nickel due to its low density. Nickel-based high-temperature alloys typically contain more than a dozen elements, with carbon considered one of the most important components. The addition of carbon helps improve the wear resistance and fatigue resistance of high-temperature alloys, enhances their high-temperature stability and mechanical properties, and extends their service life. Therefore, as an essential trace element in high-temperature alloys, the demand for Ni-C master alloys will be immeasurable.

[0003] The advantages of choosing Ni-C master alloys to replace elemental C as additives for metallic materials are mainly: (1) It can effectively reduce the melting point of pure metal C, making it easier to melt, shortening the alloy smelting time and reducing the smelting temperature; (2) Alloying can effectively solve the problem of chromium burning loss during high-temperature smelting, resulting in stable alloy composition and high element yield; (3) The smelting of master alloys can reduce the impurity content of elemental C, effectively purifying the material quality and fundamentally improving the quality of nickel raw materials. Therefore, developing and preparing Ni-C master alloy raw materials with moderate melting point, low impurity elements, and high quality using the thermal reduction method is the basis for preparing nickel-based high-temperature alloys for high-end materials. In addition, the proposal also requires promoting breakthroughs in high-temperature alloys, so vigorously promoting the development of Ni-C master alloys has significant economic and scientific value.

[0004] Patent publication number CN109112326A discloses a method for preparing nickel-carbon master alloys with a carbon content of 1%~2.5 wt.%. This method is simple and easy to implement, involving mixing pure nickel and pure carbon powders and then performing vacuum induction melting. Experimental results show that the nickel-carbon master alloy exhibits good deoxidation effects in high-temperature alloys. However, the cost of preparing nickel-carbon master alloys using pure nickel is too high, and the compositional uniformity of nickel-carbon master alloys prepared by the vacuum induction melting method is poor, with uncontrollable impurity content. 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 high-homogeneity nickel-carbon master alloy for aerospace-grade high-temperature alloys. This nickel-carbon master alloy is characterized by high homogeneity and low impurity content. Using it as an additive in the preparation of nickel-based alloys not only results in lower melting temperatures and shorter melting times, which is beneficial for obtaining a uniform microstructure in nickel-based alloys, minimizing segregation and ensuring the service performance of the material, but also improves production efficiency and alloy yield, avoids material waste, and reduces production costs. This overcomes the shortcomings of existing nickel-carbon master alloys, such as high compositional uniformity and high impurity content.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a high homogeneous nickel-carbon master alloy for aerospace-grade high-temperature alloys, characterized in that the nickel-carbon master alloy is composed of the following elements by mass percentage: C 0.5%~3.0%, with the balance being Ni and unavoidable impurities.

[0007] The above-mentioned aerospace-grade high-homogeneity nickel-carbon master alloy is characterized in that the mass percentage of each element in the unavoidable impurities is: Fe≤0.059%, Si≤0.045%, V≤0.018%, Mg≤0.032%, N≤0.15%, H≤0.042%, O≤0.10%.

[0008] The aforementioned aerospace-grade high-homogeneity nickel-carbon master alloy is characterized in that the melting point of the nickel-carbon master alloy is 1300℃~1455℃ and the density is 8.0 g·cm³. -3 ~8.7g·cm -3 .

[0009] This invention uses Ni as the matrix and heat-resistant and corrosion-resistant C as the main alloying element to form a nickel-carbon master alloy for aerospace-grade nickel-based alloys. By limiting the content of each component, a phase composed of Ni and C elements is formed within a set alloy composition range. Compared with elemental nickel and elemental carbon, the melting point of the nickel-carbon master alloy of this invention is closer to that of nickel, the matrix of nickel-based alloys, with a difference of 360°C. Furthermore, its specific heat, specific gravity, and latent heat of fusion are similar to those of the matrix nickel metal, satisfying the requirements for adding easily burnable and refractory metal components in nickel-based alloys. This effectively avoids metallurgical problems such as easy burn-out of elemental nickel and easy segregation and infusibility of elemental carbon during the smelting process of nickel-based alloys. At the same time, the hardness of the nickel-carbon master alloy of this invention is 21 HRC, which is moderate and easily broken into small particles of 0.5 mm to 5 mm, making it convenient to add as a raw material during the smelting and preparation of nickel-based alloys.

[0010] Meanwhile, this invention also discloses a low-cost method for preparing a high-homogeneity nickel-carbon master alloy for aerospace-grade high-temperature alloys, characterized by the following steps: Step 1: Prepare materials: Select nickel oxide powder and carbon powder as raw materials; Step 2, Material Drying: Dry the selected raw materials in a hot air circulating oven; Step 3, material mixing: According to the composition requirements of the target product nickel-carbon master alloy, weigh the dried raw materials from step 2 and mix them evenly to obtain the mixed material to be reacted. Step 4, Carbothermic Reduction - Electromagnetic Stirring: The mixed materials to be reacted obtained in Step 3 are placed into a graphite crucible reactor, and then the whole thing is loaded into a vacuum hot-press sintering furnace. The carbothermic reduction reaction is initiated by heating and pressurizing, and at the same time the electromagnetic induction device is turned on to perform electromagnetic stirring, so as to obtain a preheated product with a uniform composition of nickel oxide and carbon powder. Step 5, Vacuum Hot Press Sintering: The preheated product, uniformly composed of nickel oxide and carbon powder obtained in Step 4, is heated to 740℃~760℃ in a vacuum hot press sintering furnace and held at that temperature for 0.4h~0.6h. Simultaneously, the vacuum circulation system is activated to remove harmful gases generated during the reaction. Then, the sintering is performed under a vacuum of 2.7×10⁻⁶. -3 Pa ~ 4.7 × 10 -1 Under Pa conditions, the material is heated to 1300℃~1500℃ under a pressure of 8T~8.1T and then vacuum hot-pressed for 7h~8h, followed by furnace cooling to obtain a high-homogeneity nickel-carbon master alloy.

[0011] This invention ensures high alloy yield and high purity during carbothermic reduction of nickel-carbon master alloys by strictly controlling the preparation process and impurity elements in the raw materials. On the one hand, it ensures that the final nickel-carbon master alloy product has very low impurity content. At the same time, the nickel and carbon elements in the alloy are uniformly distributed and there is no infusibility. This ensures the quality of downstream nickel-based alloy products and improves the alloy yield.

[0012] This invention improves the composition, microstructure uniformity, and porosity of nickel-carbon master alloys by vacuum hot pressing and sintering the preheated product prepared by a carbothermal reduction-electromagnetic stirring linkage process. It also incorporates heating and heat preservation, while simultaneously activating a vacuum circulation system to remove harmful gases generated during the reaction. This ensures the absence of high-density inclusions and segregation defects, resulting in a more uniform distribution of nickel and carbon elements and further reducing impurities such as oxygen, nitrogen, and hydrogen. This enhances the purity and homogenization of the nickel-carbon master alloy. Furthermore, compared to directly smelting pure nickel and carbon powder, the carbothermal reduction-synthesized nickel-carbon master alloy requires a moderate sintering temperature, avoiding the high energy consumption and loss of low-melting-point nickel caused by high-temperature sintering, while significantly reducing production costs.

[0013] The present invention uses a mold with a diameter of 50mm in vacuum hot pressing sintering, and the pressure is 40MPa under a pressure of 8T~8.1T.

[0014] The above method is characterized in that the composition and particle size of the nickel oxide powder in step one conform to the YS / T277-2016 standard "Nickel Oxide", and the carbon powder has a purity of 99.99% or higher and an average mesh size of 400 mesh. This invention, by strictly controlling the purity and particle size of the reactants, ensures, on the one hand, that the reaction intensity during carbothermic reduction is moderate, avoiding excessively vigorous reactions that could lead to severe mold contamination and low alloy yield, and on the other hand, avoiding excessively mild reactions that could result in poor alloy uniformity; and on the other hand, it ensures low impurity content and high product quality in the final product.

[0015] The method described above is characterized in that the drying temperature in step two is 80℃~150℃, and the drying time is 12h~20h. This invention ensures that there is no water vapor in the reaction product by drying the reactants at a suitable temperature for a certain period of time before the reaction, thus avoiding water vapor explosion and severe reaction sputtering during the carbothermic reduction reaction.

[0016] The method described above is characterized in that the mass of carbon in the mixed reactants in step three is 5.6 times the mass of carbon required in the composition of the target product, the nickel-carbon master alloy. In this invention, 82% of the carbon needs to participate in the reduction reaction; therefore, the mass of carbon needs to be increased to meet the carbon content requirements of the nickel-carbon master alloy.

[0017] The above method is characterized in that the mixing in step three is carried out using a mixer at a speed of 40 r / min to 80 r / min for a time of 10 min to 30 min. This invention mixes low-density, high-melting-point carbon powder and nickel oxide powder, controlling the speed and time to obtain a uniformly mixed powder. This ensures the smooth progress of the subsequent carbothermic reaction while preventing carbon segregation and the formation of high-density, high-melting-point precipitates, further improving the compositional uniformity of the nickel-carbon master alloy.

[0018] The above method is characterized in that the electromagnetic stirring frequency in step four is 150 r / min to 350 r / min, the time is 15 s to 45 s, and the electromagnetic stirrer is turned off after reaching 200°C. This invention increases the fluidity of the molten reaction products by applying electromagnetic stirring at appropriate frequency and time during the carbothermic reduction synthesis of nickel-carbon master alloys. This ensures sufficient contact between the powder melt and the molten alloy, accelerates gas discharge, and prevents contamination of the alloy liquid, which could lead to poor final reaction product quality and low alloy yield. Furthermore, the added electromagnetic stirring can make the distribution of nickel and carbon elements in the alloy more uniform, avoiding the formation of high-density and infusible precipitates, thus improving the quality of the nickel-carbon alloy.

[0019] Compared with the prior art, the present invention has the following advantages: 1. The nickel-carbon master alloy product prepared by this invention has the characteristics of high homogeneity, no segregation and low impurity content. Using this nickel-carbon master alloy as a melting additive for aerospace-grade nickel-based high-temperature alloys can effectively avoid the burning loss of low-melting-point nickel and the segregation of low-density high-melting-point carbon to form refractory phases, which is conducive to obtaining nickel-based alloy products with uniform composition and structure and improving the alloy qualification rate. At the same time, adding this nickel-carbon master alloy can reduce the melting temperature, shorten the melting time and reduce the production cost.

[0020] 2. This invention combines carbothermal reduction with electromagnetic stirring during the preparation of nickel-carbon master alloys. This increases the fluidity of the molten reaction products, ensuring sufficient contact between the molten metals and the resulting alloy. This facilitates gas removal during vacuum sintering, avoids interference from gases in the alloy with the molten metal, and reduces non-metallic inclusions within the alloy, resulting in a purer and denser alloy and increased yield. Furthermore, electromagnetic stirring promotes a more uniform elemental distribution in the nickel-carbon master alloy, preventing the formation of high-density and refractory phases and improving the alloy's quality. Subsequent vacuum remelting and refining of the nickel-carbon master alloy prepared by the carbothermal reduction-electromagnetic stirring process further improves the composition, microstructure uniformity, and porosity of the alloy. This ensures the absence of metallurgical defects such as high-density inclusions and high-melting-point refractory phases, resulting in a more uniform distribution of nickel and carbon elements and further reducing impurities such as oxygen, nitrogen, and hydrogen. This, in turn, enhances the purity and homogenization of the nickel-carbon master alloy.

[0021] 3. Compared with the traditional carbothermal reduction method for preparing nickel-carbon master alloys, the carbothermal reduction-electromagnetic stirring linkage process adopted in this invention improves the fluidity of the molten reaction products, promotes the discharge of harmful gases, and is conducive to improving the final yield and purity of nickel-carbon master alloys, while also improving the compositional uniformity of nickel-carbon master alloys.

[0022] 4. Compared with the method of directly smelting elemental nickel and elemental carbon to prepare nickel-carbon master alloy, the present invention uses nickel suboxide as raw material, which is lower in cost. Moreover, the carbothermic reduction-electromagnetic stirring method proposed in this invention avoids the metallurgical problems such as easy agglomeration and difficulty in solidification of low-density, high-melting-point elemental carbon during the smelting process, making the alloy composition more uniform.

[0023] 5. The method for preparing nickel-carbon master alloy proposed in this invention is simple and effective, and suitable for large-scale industrial production.

[0024] 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

[0025] Figure 1This is a SEM image of the highly homogeneous nickel-carbon master alloy prepared in Example 1 of the present invention.

[0026] Figure 2 This is a distribution diagram of Ni element in the highly homogeneous nickel-carbon master alloy prepared in Example 1 of the present invention.

[0027] Figure 3 The image shows the carbon element distribution in the highly homogeneous nickel-carbon master alloy prepared in Example 1 of this invention. Detailed Implementation

[0028] Example 1 The aerospace-grade nickel-based alloy high homogeneous nickel-carbon master alloy of this embodiment is composed of the following elements by mass percentage: C 2.5%, with the balance being Ni and unavoidable impurities.

[0029] The method for preparing aerospace-grade nickel-based alloys with high homogeneity nickel-carbon master alloys in this embodiment includes the following steps: Step 1: Prepare materials: Select nickel oxide powder with grade NiO765 and particle size of 100 mesh (compliant with YS / T 277-2016 "Nickel Oxide" standard) and carbon powder with a purity of 99.99% or higher and an average mesh size of 400 mesh as raw materials; Step 2, Material Drying: Dry the raw materials prepared in Step 1 in a hot air circulating oven at 120℃ for 18 hours; Step 3, material mixing: According to the composition requirements of the target product nickel-carbon master alloy, and the mass of carbon is 5.6 times the mass of carbon in the composition requirements of the target product nickel-carbon master alloy, the actual added carbon element mass percentage is 14%. Weigh the dried nickel oxide powder and carbon powder from Step 2 and pour them into the mixer to mix evenly. The speed is 60 r / min and the time is 20 min to obtain the well mixed material to be reacted. Step 4, Carbothermic Reduction - Electromagnetic Stirring: Place the mixed materials to be reacted in Step 3 into a graphite crucible reactor, and load the entire reactor into a vacuum hot-press sintering furnace. Initiate the carbothermic reduction reaction by heating and pressurizing. At the same time, turn on the electromagnetic induction device to perform electromagnetic stirring. The frequency of electromagnetic stirring is 250 r / min and the time is 30 s. After reaching 200 ℃, turn off the electromagnetic stirrer to obtain a preheated product with a uniform composition of nickel oxide and carbon powder. Step 5, Vacuum Hot Press Sintering: The preheated product, uniformly composed of nickel oxide and carbon powder obtained in Step 4, is heated to 750℃ in a vacuum hot press sintering furnace and held at that temperature for 0.5h. Simultaneously, the vacuum circulation system is activated to remove harmful gases generated during the reaction. Then, the process is carried out under a vacuum of 2.7 × 10⁻⁶. -3 Pa ~ 4.7 × 10 -1Under Pa conditions, the material is heated to 1250℃ under a pressure of 8T~8.1T and then vacuum hot-pressed for 7.2h, followed by furnace cooling to obtain a high-homogeneity nickel-carbon master alloy.

[0030] The composition of the highly homogeneous nickel-carbon master alloy prepared in this embodiment was analyzed, and the results are shown in Table 1: Table 1

[0031] As shown in Table 1, the high-homogeneity nickel-carbon master alloy prepared in this embodiment has very low levels of impurity elements, especially oxygen, nitrogen and hydrogen, which avoids the impact on the brittleness of downstream titanium alloy materials.

[0032] Testing revealed that the nickel-carbon master alloy prepared in this embodiment has a melting point of 1325℃ and a density of 8.68 g·cm³. -3 .

[0033] Figure 1 The above are SEM images of the highly homogeneous nickel-carbon master alloy prepared in this embodiment. Figure 1 As can be seen from the data, the microstructure of the highly homogeneous nickel-carbon master alloy prepared in this embodiment is uniformly distributed, indicating that nickel and carbon have been fully alloyed.

[0034] Figure 2 This is a Ni element distribution diagram in the highly homogeneous nickel-carbon master alloy prepared in this embodiment. Figure 3 This is a carbon element distribution diagram in the highly homogeneous nickel-carbon master alloy prepared in this embodiment. Figure 2 and Figure 3 As can be seen from the above, the nickel and carbon elements in the highly homogeneous nickel-carbon master alloy prepared in this embodiment are uniformly distributed, achieving a highly homogeneous effect.

[0035] Example 2 The aerospace-grade nickel-based alloy high homogeneous nickel-carbon master alloy of this embodiment is composed of the following elements by mass percentage: C 3.0%, with the balance being Ni and unavoidable impurities.

[0036] The method for preparing aerospace-grade nickel-based alloys with high homogeneity nickel-carbon master alloys in this embodiment includes the following steps: Step 1: Prepare materials: Select nickel oxide powder with grade NiO765 and particle size of 100 mesh (compliant with YS / T 277-2016 "Nickel Oxide" standard) and carbon powder with a purity of 99.99% or higher and an average mesh size of 400 mesh as raw materials; Step 2, Material Drying: Dry the raw materials prepared in Step 1 in a hot air circulating oven at 140℃ for 16 hours; Step 3, material mixing: According to the composition requirements of the target product nickel-carbon master alloy, and the mass of carbon is 5.6 times the mass of carbon in the composition requirements of the target product nickel-carbon master alloy, the actual added carbon element mass percentage is 16.8%. Weigh the dried nickel oxide powder and carbon powder from Step 2 and pour them into the mixer to mix evenly. The speed is 70 r / min and the time is 25 min to obtain the well mixed material to be reacted. Step 4, Carbothermic Reduction - Electromagnetic Stirring: Place the mixed materials to be reacted in Step 3 into a graphite crucible reactor, and load the entire reactor into a vacuum hot-press sintering furnace. Initiate the carbothermic reduction reaction by heating and pressurizing, and at the same time turn on the electromagnetic induction device to perform electromagnetic stirring. The frequency of electromagnetic stirring is 300 r / min and the time is 40 s. After reaching 200 ℃, turn off the electromagnetic stirrer to obtain a preheated product with a uniform composition of nickel oxide and carbon powder. Step 5, Vacuum Hot Press Sintering: The preheated product, uniformly composed of nickel oxide and carbon powder obtained in Step 4, is heated to 750℃ in a vacuum hot press sintering furnace and held at that temperature for 0.5h. Simultaneously, the vacuum circulation system is activated to remove harmful gases generated during the reaction. Then, the process is carried out under a vacuum of 2.7 × 10⁻⁶. -3 Pa ~ 4.7 × 10 -1 Under Pa conditions, the material is heated to 1300℃ under a pressure of 8T~8.1T and then vacuum hot-pressed for 7.5h, followed by furnace cooling to obtain a high-homogeneity nickel-carbon master alloy.

[0037] The composition of the high-homogeneity nickel-carbon master alloy prepared in this embodiment was analyzed, and the results are shown in Table 2: Table 2

[0038] As shown in Table 2, the high-homogeneity nickel-carbon master alloy prepared in this embodiment has very low levels of impurity elements, especially oxygen, nitrogen and hydrogen, which avoids the impact on the brittleness of downstream titanium alloy materials.

[0039] Testing revealed that the nickel-carbon master alloy prepared in this embodiment has a melting point of 1453℃ and a density of 8.21 g·cm³. -3 .

[0040] Example 3 The aerospace-grade nickel-based alloy high homogeneous nickel-carbon master alloy of this embodiment is composed of the following elements by mass percentage: C 0.5%, with the balance being Ni and unavoidable impurities.

[0041] The method for preparing aerospace-grade nickel-based alloys with high homogeneity nickel-carbon master alloys in this embodiment includes the following steps: Step 1: Prepare materials: Select nickel oxide powder with grade NiO765 and particle size of 100 mesh (compliant with YS / T 277-2016 "Nickel Oxide" standard) and carbon powder with a purity of 99.99% or higher and an average mesh size of 400 mesh as raw materials; Step 2, Material Drying: Dry the raw materials prepared in Step 1 in a hot air circulating oven at 80℃ for 12 hours; Step 3, material mixing: According to the composition requirements of the target product nickel-carbon master alloy, and the mass of carbon is 5.6 times the mass of carbon in the composition requirements of the target product nickel-carbon master alloy, the actual added carbon element mass percentage is 2.8%. Weigh the dried nickel oxide powder and carbon powder from Step 2 and pour them into the mixer to mix evenly. The speed is 40 r / min and the time is 10 min to obtain the well mixed material to be reacted. Step 4, Carbothermic Reduction - Electromagnetic Stirring: Place the mixed materials to be reacted in Step 3 into a graphite crucible reactor, and put the entire reactor into a vacuum hot-press sintering furnace. Heat and pressurize to initiate the carbothermic reduction reaction. At the same time, turn on the electromagnetic induction device to perform electromagnetic stirring. The frequency of electromagnetic stirring is 150 r / min and the time is 15 s. After reaching 200℃, turn off the electromagnetic stirrer to obtain a preheated product with a uniform composition of nickel oxide and carbon powder. Step 5, Vacuum Hot Press Sintering: The preheated product, uniformly composed of nickel oxide and carbon powder obtained in Step 4, is heated to 740℃ in a vacuum hot press sintering furnace and held at that temperature for 0.6 hours. Simultaneously, the vacuum circulation system is activated to remove harmful gases generated during the reaction. Then, the process is carried out under a vacuum of 2.7 × 10⁻⁶. -3 Pa ~ 4.7 × 10 -1 Under Pa conditions, the material is heated to 1300℃ under a pressure of 8T~8.1T and vacuum hot-pressed for 7 hours, followed by furnace cooling to obtain a high-homogeneity nickel-carbon master alloy.

[0042] The composition of the highly homogeneous nickel-carbon master alloy prepared in this embodiment was analyzed, and the results are shown in Table 3: Table 3

[0043] As shown in Table 3, the high-homogeneity nickel-carbon master alloy prepared in this embodiment has very low levels of impurity elements, especially oxygen, nitrogen and hydrogen, which avoids the impact on the brittleness of downstream titanium alloy materials.

[0044] Testing revealed that the nickel-carbon master alloy prepared in this embodiment has a melting point of 1406℃ and a density of 8.14 g·cm³. -3 .

[0045] Example 4 The aerospace-grade nickel-based alloy high homogeneous nickel-carbon master alloy of this embodiment is composed of the following elements by mass percentage: C 2.0%, with the balance being Ni and unavoidable impurities.

[0046] The method for preparing aerospace-grade nickel-based alloys with high homogeneity nickel-carbon master alloys in this embodiment includes the following steps: Step 1: Prepare materials: Select nickel oxide powder with grade NiO765 and particle size of 100 mesh (compliant with YS / T 277-2016 "Nickel Oxide" standard) and carbon powder with a purity of 99.99% or higher and an average mesh size of 400 mesh as raw materials; Step 2, Material Drying: Dry the raw materials prepared in Step 1 in a hot air circulating oven at 150℃ for 14 hours; Step 3, material mixing: According to the composition requirements of the target product nickel-carbon master alloy, and the mass of carbon is 5.6 times the mass of carbon in the composition requirements of the target product nickel-carbon master alloy, the actual added carbon element mass percentage is 11.2%. Weigh the dried nickel oxide powder and carbon powder from Step 2 and pour them into the mixer to mix evenly. The speed is 80 r / min and the time is 30 min to obtain the well mixed material to be reacted. Step 4, Carbothermic Reduction - Electromagnetic Stirring: Place the mixed materials to be reacted in Step 3 into a graphite crucible reactor, and put the entire reactor into a vacuum hot-press sintering furnace. Heat and pressurize to initiate the carbothermic reduction reaction. At the same time, turn on the electromagnetic induction device to perform electromagnetic stirring. The frequency of electromagnetic stirring is 350 r / min and the time is 45 s. After reaching 200 ℃, turn off the electromagnetic stirrer to obtain a preheated product with a uniform composition of nickel oxide and carbon powder. Step 5, Vacuum Hot Press Sintering: The preheated product, uniformly composed of nickel oxide and carbon powder obtained in Step 4, is heated to 760℃ in a vacuum hot press sintering furnace and held at that temperature for 0.4h. Simultaneously, the vacuum circulation system is activated to remove harmful gases generated during the reaction. Then, the process is carried out under a vacuum of 2.7 × 10⁻⁶. -3 Pa ~ 4.7 × 10 -1 Under Pa conditions, the material is heated to 1280℃ under a pressure of 8T~8.1T and then vacuum hot-pressed for 8 hours, followed by furnace cooling to obtain a high-homogeneity nickel-carbon master alloy.

[0047] The composition of the high-homogeneity nickel-carbon master alloy prepared in this embodiment was analyzed, and the results are shown in Table 4: Table 4

[0048] As shown in Table 4, the high-homogeneity nickel-carbon master alloy prepared in this embodiment has very low levels of impurity elements, especially oxygen, nitrogen and hydrogen, which avoids the impact on the brittleness of downstream titanium alloy materials.

[0049] Testing revealed that the nickel-carbon master alloy prepared in this embodiment has a melting point of 1432℃ and a density of 8.18 g·cm³. -3 .

[0050] 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 technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A high homogenization nickel-carbon master alloy for aerospace grade high temperature alloys, characterized in that, The nickel-carbon intermediate alloy is composed of the following elements in mass percentage: C 0.5%~3.0%, the balance being Ni and inevitable impurities.

2. The high homogenized nickel-carbon intermediate alloy for aerospace-grade high-temperature alloys according to claim 1, characterized in that, The mass percentage of each element in the inevitable impurities is: Fe≤0.059%, Si≤0.045%, V≤0.018%, Mg≤0.032%, N≤0.15%, H≤0.042%, O≤0.10%.

3. The high homogenized nickel-carbon master alloy for aerospace and aviation grade high-temperature alloy according to claim 1, characterized in that, The melting point of the nickel-carbon intermediate alloy is 1300-1455℃, and the density is 8.0-8.7g·cm -3 . -3 .

4. A low cost method of producing a high homogenization nickel-carbon intermediate alloy for aerospace grade high temperature alloys as claimed in any one of claims 1 to 3, characterized in that, The method comprises the following steps: Step one, preparing materials: selecting nickel protoxide powder and carbon powder as raw materials; Step two, drying the materials: drying the selected raw materials in step one in a hot air circulation oven; Step three, mixing the materials: according to the composition requirements of the target product nickel-carbon intermediate alloy, weighing the dried raw materials in step two and mixing them uniformly to obtain mixed reaction materials; Step four, carbon thermal reduction-electromagnetic stirring: placing the mixed reaction materials obtained in step three into a graphite crucible reactor, then loading the whole into a vacuum hot-pressing sintering furnace, raising the temperature and pressure to initiate the carbon thermal reduction reaction, and simultaneously starting the electromagnetic induction equipment for electromagnetic stirring to obtain a preheating product composed of nickel protoxide and carbon powder uniformly. Step five, vacuum hot-press sintering: the preheated product of the uniform composition of nickel oxide and carbon powder obtained in step four is heated to 740-760℃ in a vacuum hot-press sintering furnace and kept for 0.4-0.6h, while the vacuum circulation system is started to remove the harmful gases generated during the reaction, and then the vacuum degree is kept at 2.7×10 -3 Pa~4.7×10 -1 Pa, kept at 8T-8.1T pressure, heated to 1300-1500℃, vacuum hot-press sintered for 7-8h, and then cooled with the furnace to obtain high homogenized nickel-carbon intermediate alloy.

5. The method of claim 4, wherein, The composition and particle size of the nickel protoxide powder in step one meet the YS / T 277-2016 “Nickel Protoxide” standard, and the mass purity of the carbon powder is more than 99.99%, and the average mesh number is 400 mesh.

6. The method of claim 4, wherein, The drying temperature in step two is 80℃~150℃, and the time is 12h~18h.

7. The method of claim 4, wherein, The mass of carbon in the mixed reaction materials in step three is 5.6 times the mass of carbon in the composition requirements of the target product nickel-carbon intermediate alloy.

8. The method of claim 4, wherein, The mixing in step three is carried out by a mixer, and the rotating speed is 40r / min~80r / min, and the time is 10min~30min.

9. The method of claim 4, wherein, The frequency of the electromagnetic stirring in step four is 150r / min~350r / min, the time is 15s~45s, and the electromagnetic stirrer is turned off after reaching 200℃.

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