A molybdenum-vanadium-aluminum-chromium-iron intermediate alloy, a preparation method and application thereof

Abstract

This invention provides a molybdenum-vanadium-aluminum-chromium-iron master alloy, its preparation method, and its applications. The master alloy comprises the following components in the indicated mass percentages: Mo: 27%-34%, V: 24%-30%, Al: 24%-36%, Cr: 3%-8%, Fe: 4%-8%, and unavoidable impurities. The master alloy has a melting point of 1500℃-1520℃ and a density of 4.90 g·cm³. ‑3 -5.00 g·cm ‑3 The particle size D90 is 0.010mm-0.050mm. The molybdenum-vanadium-aluminum-chromium-iron master alloy of this invention is prepared by a one-step method + radio frequency plasma spheroidization technology. It has uniform composition and particle size, small elemental segregation and low impurity content, which can effectively reduce ingot segregation generated during titanium alloy smelting. This master alloy has good application prospects and large-scale promotion potential in the field of TC18 titanium alloy.

Description

Technical Field

[0001] This invention relates to alloy technology, and more particularly to a molybdenum-vanadium-aluminum-chromium-iron master alloy, its preparation method, and its applications. Background Technology

[0002] Titanium alloys possess excellent properties, such as high specific strength, superior corrosion resistance, and strong high-temperature resistance, making them widely used in aerospace, machinery, chemical engineering, metallurgy, energy, and military industries. With the continuous advancement of human exploration of space and the deep sea, the requirements for titanium alloys to operate under high temperature, high pressure, and high corrosion conditions are gradually increasing.

[0003] α+β type titanium alloys are a class of dual-phase titanium alloys possessing both an α phase (hexagonal close-packed structure) and a β phase (body-centered cubic structure). The phase ratio is adjusted by adding β-stabilizing elements (such as V, Mo, Cr, etc.). Due to their high strength, heat resistance, and excellent machinability, dual-phase titanium alloys are widely used in aerospace, medical, shipbuilding, chemical, and automotive industries. There are many types of titanium alloys with this structure, such as the foreign grades Ti-6242, Ti-5553, IMI834, and BT22, and the domestic grades TC4, TC11, TC17, and TC21.

[0004] TC18 titanium alloy is a heat-resistant, high-strength titanium alloy with an α+β dual-phase structure. Its nominal composition is Ti-5Al-4.75Mo-4.75V-1Cr-1Fe. It possesses both high strength (annealed strength ≥1080MPa) and deep hardenability (maximum cross-sectional thickness up to 250mm), along with high toughness, excellent plasticity, and good weldability. It can be used to manufacture fan discs and blades for aerospace engines, as well as variable stress components such as fuselages and wings, and parts for control systems that maintain stable operation under moderate strength and stress for a certain period. Currently, the common manufacturing process for TC18 titanium alloy involves mixing sponge titanium, molybdenum-aluminum binary alloys, vanadium-aluminum binary alloys, chromium-aluminum binary alloys, and iron powder, pressing them into electrodes, and then melting them into ingots using a vacuum arc remelting furnace. The melting process requires a variety of materials with significant differences in melting point and density, which can easily lead to defects such as raw material burn-off and elemental segregation within the ingot during manufacturing.

[0005] Currently, the main methods for preparing multi-element intermediate alloys that provide raw materials for TC18 titanium alloys are the out-of-furnace aluminothermic method, which involves mixing the oxides of the required alloying elements with metallic aluminum and then using an aluminothermic reduction reaction; or the out-of-furnace aluminothermic method combined with vacuum induction melting, which involves first combining some alloying elements into a transition intermediate alloy and then using a vacuum induction melting process for final melting.

[0006] For example, CN112680647 A discloses a pentagonal master alloy for TC18 titanium alloy ingot smelting and its preparation method. The preparation process involves using aluminum as a reducing agent, vanadium pentoxide, molybdenum trioxide, and chromium trioxide as oxidizing agents, and adding iron powder. An alumina crucible is used as the reaction vessel, and the materials are mixed evenly before being smelted using an out-of-furnace aluminothermic process to obtain a vanadium-molybdenum-chromium-iron-aluminum master alloy. This method has advantages such as simple equipment, convenient operation, and low investment. However, its disadvantages include the presence of numerous oxidation and discoloration regions inside the prepared alloy ingot, leading to a significant increase in its oxygen content. Furthermore, elemental segregation is prone to occur within the prepared multi-element alloy, which has a detrimental effect on the subsequent TC18 titanium alloy smelting, reducing the final quality of the TC18 titanium alloy ingot and components.

[0007] For example, CN102618739 A discloses a five-element master alloy of aluminum, molybdenum, vanadium, chromium, and iron, and its preparation method. The preparation process involves using aluminum as a reducing agent and molybdenum trioxide and vanadium pentoxide as oxidizing agents, employing an aluminothermic reduction reaction to prepare a molybdenum-vanadium-aluminum alloy. Then, the molybdenum-vanadium-aluminum alloy, iron powder, metallic chromium, and aluminum granules are combined using a vacuum induction melting process to prepare the aluminum-molybdenum-vanadium-chromium-iron master alloy. This method has advantages such as uniform alloy composition and minimal elemental segregation, but its preparation process is relatively cumbersome, the production cycle is long, and the carbon crucible used needs to be coated with a layer of yttrium oxide, increasing production costs and hindering the widespread adoption of the process. Summary of the Invention

[0008] The purpose of this invention is to address the problems of internal oxidation and elemental segregation in the preparation of TC18 titanium alloys using aluminothermic reduction alone, as well as the high requirements and cumbersome process of vacuum induction melting. This invention proposes a molybdenum-vanadium-aluminum-chromium-iron master alloy, prepared using a one-step method combined with radio frequency plasma spheroidization technology. This master alloy exhibits uniform composition and particle size, minimal elemental segregation, and low impurity content, effectively reducing ingot segregation during titanium alloy melting. This master alloy shows promising application prospects and large-scale promotion potential in the field of TC18 titanium alloys.

[0009] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," "consisting of," etc., and similar meanings.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is: a molybdenum-vanadium-aluminum-chromium-iron master alloy, comprising the following components in mass percentage: Mo: 27%-34%, V: 24%-30%, Al: 24%-36%, Cr: 3%-8%, Fe: 4%-8%, and unavoidable impurities.

[0011] Furthermore, the molybdenum-vanadium-aluminum-chromium-iron master alloy comprises the following components in mass percentage: Mo: 28%-32%, V: 26%-30%, Al: 28%-32%, Cr: 5%-7%, Fe: 5%-7%, and unavoidable impurities.

[0012] Furthermore, the impurities in the molybdenum-vanadium-aluminum-chromium-iron master alloy are: Si: 0.30% Max, C: 0.04% Max, S: 0.01% Max, O: 0.20% Max, N: 0.04% Max, and other single elements: 0.05% Max.

[0013] Furthermore, the melting point of the molybdenum-vanadium-aluminum-chromium-iron master alloy is 1500℃-1520℃, and the density of the molybdenum-vanadium-aluminum-chromium-iron master alloy is 4.90 g·cm³. -3 -5.00 g·cm -3 .

[0014] Furthermore, the particle size D90 of the molybdenum-vanadium-aluminum-chromium-iron master alloy is 0.010mm-0.050mm.

[0015] Another object of the present invention discloses a method for preparing a molybdenum-vanadium-aluminum-chromium-iron master alloy, comprising the following steps:

[0016] Step 1: Mix molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and aluminum powder in a mass ratio of (0.550-0.600):(0.620-0.670):(0.105-0.120):(0.100-0.110):1, add the mixture to a reaction crucible, ignite the reaction, and react at a temperature of 2100℃-2200℃ for 30s-45s to obtain a primary alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy.

[0017] Step 2: Crush the molybdenum-vanadium-aluminum-chromium-iron primary alloy using a crusher to obtain molybdenum-vanadium-aluminum-chromium-iron primary alloy powder;

[0018] Step 3: Using the aforementioned molybdenum-vanadium-aluminum-chromium-iron primary alloy powder as raw material, a molybdenum-vanadium-aluminum-chromium-iron intermediate alloy is produced using radio frequency plasma spheroidization technology.

[0019] Furthermore, the purity of molybdenum trioxide (MoO3) is ≥99.0%, the purity of vanadium pentoxide (V2O5) is ≥99.5%, the purity of chromium trioxide (Cr2O3) is ≥99.0%, the purity of ferric oxide (Fe2O3) is ≥99.0%, and the particle size of metallic aluminum (Al) powder is 0.3mm-3.0mm with a purity of ≥99.7%.

[0020] Furthermore, the particle size of the aluminum powder is 0.3mm-3.0mm.

[0021] Furthermore, before step 1, molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and aluminum powder are dried in a constant temperature drying room at 50℃-60℃ for 22h-24h to ensure that the moisture content of the reaction materials is ≤0.1% and the initial temperature is 40℃-50℃.

[0022] Furthermore, in step 1, the mass ratio of molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder is 0.586:0.658:0.112:0.107:1.

[0023] Furthermore, in step 1, aluminothermic reduction reaction is used to prepare a primary alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy, and the reaction crucible is an aluminum oxide (Al2O3) crucible. In order to make full use of the slag (Al2O3) produced by the reaction, the furnace lining of the reaction device is made of slag, which can effectively reduce the introduction of impurities and further reduce the impurity content in the alloy, thus saving costs and achieving the purpose of recycling raw materials.

[0024] Furthermore, the aluminothermic reduction reaction does not require heating. The igniter used is magnesium powder (Mg), aluminum powder, and calcium peroxide (CaO2). During use, the mixture is easily ignited by the combustion of the magnesium powder, aluminum powder, and calcium peroxide powder. As a side reaction, the heat generated initiates the main reaction.

[0025] Furthermore, before crushing in step 2, the molybdenum-vanadium-aluminum-chromium-iron primary alloy is polished and cleaned to obtain a high-quality semi-finished alloy block. The molybdenum-vanadium-aluminum-chromium-iron primary alloy (molybdenum-vanadium-aluminum-chromium-iron quaternary alloy) prepared by the aluminothermic reduction reaction has a slight oxide layer on its appearance that can be removed by polishing. After polishing, the alloy is silvery bright and has good surface quality.

[0026] Furthermore, the particle size of the molybdenum-vanadium-aluminum-chromium-iron primary alloy powder described in step 2 is 0-0.3 mm.

[0027] Furthermore, the equipment used in the radio frequency plasma spheroidization technology described in step 3 is a radio frequency plasma spheroidization device (also known as a plasma spheroidization device), which consists of four parts: a high-frequency power supply system, a gas supply and powder delivery system, a reaction and collection system, and an auxiliary system.

[0028] Further, the specific steps of step 3, which uses the aforementioned molybdenum-vanadium-aluminum-chromium-ferroalloy primary alloy powder as raw material and employs radio frequency plasma spheroidization technology to produce the molybdenum-vanadium-aluminum-chromium-ferroalloy intermediate alloy, are as follows: First, turn on the gas supply system and fill the equipment with high-purity argon gas as the working gas, controlling the flow rate at 15 L·min. -1 Up to 20 L·min -1 Continue for 5-10 minutes to establish the desired atmosphere;

[0029] Then, the sheath gas valve was opened, and high-purity helium was introduced at a flow rate of 40 L / min.-1 -60 L·min -1 Inflation time: 5-6 minutes;

[0030] Turn on the high-frequency power supply and set the power to 25 kW-40 kW to generate a high-temperature plasma torch flame;

[0031] After the plasma torch flame stabilizes, the carrier gas argon is started to transport the primary alloy powder of molybdenum-vanadium-aluminum-chromium-iron at a rate of 40 g·min. -1 -100 g·min -1 Molybdenum-vanadium-aluminum-chromium-ferroalloy primary alloy powder carried by carrier gas is melted into droplets in a high-temperature reaction chamber and then enters a cooling chamber. Under the combined action of an argon atmosphere and an auxiliary water cooling system in the cooling chamber, the molten droplets are cooled, solidified, and spheroidized to prepare the molybdenum-vanadium-aluminum-chromium-ferroalloy intermediate alloy. The preferred ratio of argon flow rate, helium flow rate, and powder flow rate is 3L-4L:8L-12L:8g-20g.

[0032] Furthermore, the purity of the argon gas is ≥99.99%.

[0033] Furthermore, the purity of the helium gas is ≥99.99%.

[0034] Furthermore, the pressure inside the high-temperature reaction chamber is 1.5 Pa to 2.5 Pa. The "high temperature" in the high-temperature reaction chamber refers to the very high temperature of the plasma flame core (8000℃-10000℃), not a stable and continuous high temperature throughout the reaction chamber.

[0035] Furthermore, the particle size D90 of the molybdenum-vanadium-aluminum-chromium-iron master alloy is 0.010mm-0.050mm.

[0036] Another objective of this invention is to disclose the application of a molybdenum-vanadium-aluminum-chromium-iron master alloy in the field of TC18 titanium alloys.

[0037] Furthermore, the mass ratio of molybdenum-vanadium-aluminum-chromium-iron master alloy to Ti in the TC18 titanium alloy is 0.195-0.200:1.

[0038] This invention discloses a molybdenum-vanadium-aluminum-chromium-iron master alloy, its preparation method, and its applications, which have the following advantages compared with existing technologies:

[0039] 1) This invention presents a molybdenum-vanadium-aluminum-chromium-ferrochrome master alloy, a multi-element master alloy primarily used as a raw material for smelting TC18 titanium alloy. Traditional multi-element alloys generally suffer from problems such as numerous internal oxidation regions and significant element segregation. In the preparation of TC18 titanium alloy, they easily introduce impurities such as oxygen and nitrogen, and also easily cause uneven element distribution within the ingot. If multiple binary alloys are used for smelting, element loss is likely, resulting in a complex process and a long production cycle. This invention, through a reasonable element ratio and optimized preparation process, provides multiple alloying elements while reducing the types of raw materials, improving raw material purity, reducing the technical difficulty of vacuum consumable melting, and effectively reducing inclusions and element segregation defects in titanium alloy ingots.

[0040] 2) In the molybdenum-vanadium-aluminum-chromium-iron master alloy of the present invention, each element has a specific effect on the properties of TC18 titanium alloy: Mo can strengthen the β phase through solid solution, significantly reduce the phase transformation point, thereby improving the strength, hardness, high-temperature stability and creep resistance of the alloy; V and Cr elements, as isomorphic and eutectoid β stabilizing elements respectively, exist in the β phase in the form of substitutional solid solution, producing a solid solution strengthening effect. Among them, V element can also significantly improve the hardenability and microstructure stability of titanium alloy; Al element can stabilize the α phase, play a good solid solution strengthening role, promote the precipitation of α phase during heat treatment and enhance the age strengthening effect; Fe element can significantly reduce the β phase transformation point, stabilize the β phase, promote the uniform distribution of α and β phase components, and refine the α lamellar grains, producing solid solution strengthening and precipitation strengthening effects.

[0041] However, the content of each element must be strictly controlled: excessive Mo content may precipitate harmful δ phase, which seriously impairs the ductility and fatigue life of the alloy; excessive Al content is prone to forming brittle compounds such as Ti3Al or TiAl at the grain boundaries, affecting the alloy performance; excessive Cr content may generate brittle phases such as TiCr2, reducing fracture toughness; excessive Fe content will exacerbate the segregation tendency, causing local brittleness during the melting process, which poses a hidden danger to the safety of the component.

[0042] Therefore, the contents of elements such as Mo, V, Al, Cr, and Fe in the intermediate alloy of this invention are specifically designed according to the preparation specifications of TC18 titanium alloy, aiming to simplify the process and reduce costs. Any changes beyond the composition range of this invention may have a significant impact on the composition or properties of the final titanium alloy.

[0043] 3) The molybdenum-vanadium-aluminum-chromium-iron master alloy powder of the present invention is subjected to melting and spheroidizing treatment by high-temperature plasma torch flame, which can effectively remove oxygen, nitrogen and other low-melting-point impurities, thereby obtaining a high-purity molybdenum-vanadium-aluminum-chromium-iron master alloy.

[0044] 4) The molybdenum-vanadium-aluminum-chromium-iron master alloy of the present invention has good uniformity. The alloy powder prepared by radio frequency plasma spheroidization technology has fine and uniform particles and a high degree of spheroidization. When used as a raw material for smelting TC18 titanium alloy, elemental segregation is not easily generated inside the titanium alloy ingot.

[0045] 5) The molybdenum-vanadium-aluminum-chromium-iron master alloy of this invention facilitates the preparation of TC18 titanium alloy. This master alloy can provide Mo, V, Al, Cr, and Fe elements in appropriate proportions and is prepared into master alloy powder with small and uniform particle size. Only sponge titanium needs to be added (no other materials need to be added) to press it into a melting electrode, and then prepare titanium alloy ingots. This significantly simplifies the production process of TC18 titanium alloy ingots and avoids problems such as raw material burn-off and element segregation inside the titanium alloy ingot caused by too many types of raw materials and uneven particle size.

[0046] In summary, this invention utilizes a one-step method combined with radio frequency plasma spheroidization technology to prepare a molybdenum-vanadium-aluminum-chromium-iron master alloy with accurate chemical composition, high purity, and simple production process. It has promising application prospects and large-scale promotion potential in the field of TC18 titanium alloys. Attached Figure Description

[0047] Figure 1 This is a flowchart of the preparation method for a molybdenum-vanadium-aluminum-chromium-iron master alloy. Detailed Implementation

[0048] The present invention will be further described below with reference to embodiments. 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:

[0049] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0050] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0051] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0052] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0053] In this specification, the terms "optional" or "optional" are used to indicate the use or omission of certain substances, components, procedures, application conditions, etc.

[0054] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0055] Unless otherwise specified, all reagents or instruments used in this instruction manual are commercially available products.

[0056] Example 1:

[0057] This embodiment discloses a molybdenum-vanadium-aluminum-chromium-iron master alloy, designed with a Mo design value of 30%, a V design value of 28%, an Al design value of 30%, a Cr design value of 6%, and a Fe design value of 6%.

[0058] The preparation method of the molybdenum-vanadium-aluminum-chromium-iron master alloy includes the following steps:

[0059] The first step is to produce a primary alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy using the aluminothermic reduction reaction method:

[0060] The production of primary alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy is carried out according to the following steps: furnace construction, furnace firing, material drying, batching, mixing, furnace loading, reaction, cooling, furnace dismantling, finishing, crushing, and sampling analysis.

[0061] Preparation of primary alloys of molybdenum-vanadium-aluminum-chromium-iron by the aluminothermic method

[0062] The crucible was made of alumina refractory material and sintered in a natural gas sintering furnace for 7 hours. The sintering temperature was gradually increased from 30℃ to 600℃. After sintering, the temperature was held for 2 hours.

[0063] Molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder were dried at a temperature of 60°C for 24 hours.

[0064] The alloy mass ratio for the aluminothermic reaction process is calculated as follows: the mass ratio of molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder is 0.586:0.658:0.112:0.107:1.

[0065] The mixture of molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder is loaded into a special mixing tank and placed into a mixer at 10 r·min. -1 The materials are mixed at a rate of [missing information], with a mixing time of 20 minutes. Mixing requirements: All raw materials must be thoroughly and evenly mixed to ensure sufficient contact between them;

[0066] The mixed molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide and metallic aluminum powder were loaded into a preheated alumina crucible, ignited and reacted, and then cooled for 36 hours before being taken out of the furnace to obtain a primary alloy of molybdenum vanadium aluminum chromium ferrometallurgy.

[0067] The oxide film on the surface of the alloy ingot is removed by grinding with a grinding wheel; it is then crushed to a particle size of 0-50mm by a crusher, and after magnetic separation and manual sorting to remove impurities such as ferromagnetic materials, it is sampled for analysis.

[0068] The second step is crushing with a crusher:

[0069] Semi-finished alloys that meet the design specifications, have a bright and dense structure, and are free of oxidation defects are crushed to a particle size of 0-0.3mm using a crusher.

[0070] The third step involves producing a molybdenum-vanadium-aluminum-chromium-iron master alloy using a radio frequency plasma spheroidization process.

[0071] Turn on the radio frequency plasma spheroidization system, open the gas supply system, and fill the equipment with high-purity argon gas at a flow rate of 20 L / min. -1 Inflation time: 5 minutes; Open the sheath gas valve and fill with high-purity helium at a flow rate of 50 L / min. -1 The inflation time is 5 minutes. Once the gas in all chambers is flowing continuously and stably, turn on the high-frequency power supply (30kW). After a stable high-temperature plasma torch flame is generated, start the carrier gas feeding at a rate of 60 g / min. -1 ;

[0072] After the material is completely fed into the reaction chamber by the carrier gas system and the primary alloy powder of molybdenum-vanadium-aluminum-chromium-iron is melted and spheroidized into finer alloy powder, the system is shut off and cooled for 3 hours. The spheroidized powder is then collected to obtain the intermediate alloy of molybdenum-vanadium-aluminum-chromium-iron.

[0073] The chemical composition analysis of the molybdenum-vanadium-aluminum-chromium-iron master alloy prepared in this embodiment was performed, and the results are shown in Table 1. The melting point of the molybdenum-vanadium-aluminum-chromium-iron master alloy prepared in this embodiment is 1509℃, and the density is 4.92 g·cm³. -3 .

[0074] Example 2:

[0075] This embodiment discloses a molybdenum-vanadium-aluminum-chromium-iron master alloy, designed with a Mo design value of 28%, a V design value of 26%, an Al design value of 36%, a Cr design value of 5%, and a Fe design value of 5%.

[0076] The preparation method of the molybdenum-vanadium-aluminum-chromium-iron master alloy includes the following steps:

[0077] The first step is to produce a primary alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy using the aluminothermic reduction reaction method:

[0078] The production of primary alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy is carried out according to the following steps: furnace construction, furnace firing, material drying, batching, mixing, furnace loading, reaction, cooling, furnace dismantling, finishing, crushing, and sampling analysis.

[0079] Preparation of primary alloys of molybdenum-vanadium-aluminum-chromium-iron by the aluminothermic method

[0080] The crucible was made of alumina refractory material and sintered in a natural gas sintering furnace for 7 hours. The sintering temperature was gradually increased from 30℃ to 600℃. After sintering, the temperature was held for 2 hours.

[0081] Molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder were dried at a temperature of 60°C for 24 hours.

[0082] The alloy mass ratio for the aluminothermic reaction process is calculated as follows: the mass ratio of molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder is 0.533:0.596:0.092:0.086:1.

[0083] The mixture of molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder is loaded into a special mixing tank and placed into a mixer at 10 r·min. -1 The materials are mixed at a rate of [missing information], with a mixing time of 20 minutes. Mixing requirements: All raw materials must be thoroughly and evenly mixed to ensure sufficient contact between them;

[0084] The mixed molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide and metallic aluminum powder were loaded into a preheated alumina crucible, ignited and reacted, and then cooled for 36 hours before being taken out of the furnace to obtain a primary alloy of molybdenum vanadium aluminum chromium ferrometallurgy.

[0085] The oxide film on the surface of the alloy ingot is removed by grinding with a grinding wheel; it is then crushed to a particle size of 0-50mm by a crusher, and after magnetic separation and manual sorting to remove impurities such as ferromagnetic materials, it is sampled for analysis.

[0086] The second step is crushing with a crusher:

[0087] Semi-finished alloys that meet the design specifications, have a bright and dense structure, and are free of oxidation defects are crushed to a particle size of 0-0.3mm using a crusher.

[0088] The third step involves producing a molybdenum-vanadium-aluminum-chromium-iron master alloy using a radio frequency plasma spheroidization process.

[0089] Turn on the radio frequency plasma spheroidization system, open the gas supply system, and fill the equipment with high-purity argon gas at a flow rate of 15 L / min. -1 Inflation time: 5 minutes; Open the sheath gas valve and fill with high-purity helium at a flow rate of 40 L / min. -1 The inflation time is 5 minutes. Once the gas in all chambers is flowing continuously and stably, turn on the high-frequency power supply (25kW). After a stable high-temperature plasma torch flame is generated, start the carrier gas feeding at a rate of 40 g / min. -1 ;

[0090] After the material is completely fed into the reaction chamber by the carrier gas system and the primary alloy powder of molybdenum-vanadium-aluminum-chromium-iron is melted and spheroidized into finer alloy powder, the system is shut off and cooled for 3 hours. The spheroidized powder is then collected to obtain the intermediate alloy of molybdenum-vanadium-aluminum-chromium-iron.

[0091] The chemical composition analysis of the molybdenum-vanadium-aluminum-chromium-iron master alloy prepared in this embodiment was performed, and the results are shown in Table 1. The melting point of the molybdenum-vanadium-aluminum-chromium-iron master alloy prepared in this embodiment is 1504℃, and the density is 4.91 g·cm³. -3 .

[0092] Example 3:

[0093] This embodiment discloses a molybdenum-vanadium-aluminum-chromium-iron master alloy, designed with a Mo design value of 32%, a V design value of 30%, an Al design value of 24%, a Cr design value of 7%, and a Fe design value of 7%.

[0094] The preparation method of the molybdenum-vanadium-aluminum-chromium-iron master alloy includes the following steps:

[0095] The first step is to produce a primary alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy using the aluminothermic reduction reaction method:

[0096] The production of primary alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy is carried out according to the following steps: furnace construction, furnace firing, material drying, batching, mixing, furnace loading, reaction, cooling, furnace dismantling, finishing, crushing, and sampling analysis.

[0097] Preparation of primary alloys of molybdenum-vanadium-aluminum-chromium-iron by the aluminothermic method

[0098] The crucible was made of alumina refractory material and sintered in a natural gas sintering furnace for 7 hours. The sintering temperature was gradually increased from 30℃ to 600℃. After sintering, the temperature was held for 2 hours.

[0099] Molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder were dried at a temperature of 60°C for 24 hours.

[0100] The alloy mass ratio for the aluminothermic reaction process is calculated as follows: the mass ratio of molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder is 0.641:0.724:0.135:0.128:1.

[0101] The mixture of molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and metallic aluminum powder is loaded into a special mixing tank and placed into a mixer at 10 r·min. -1 The materials are mixed at a rate of [missing information], with a mixing time of 20 minutes. Mixing requirements: All raw materials must be thoroughly and evenly mixed to ensure sufficient contact between them;

[0102] The mixed molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide and metallic aluminum powder were loaded into a preheated alumina crucible, ignited and reacted, and then cooled for 36 hours before being taken out of the furnace to obtain a primary alloy of molybdenum vanadium aluminum chromium ferrometallurgy.

[0103] The oxide film on the surface of the alloy ingot is removed by grinding with a grinding wheel; it is then crushed to a particle size of 0-50mm by a crusher, and after magnetic separation and manual sorting to remove impurities such as ferromagnetic materials, it is sampled for analysis.

[0104] The second step is crushing with a crusher:

[0105] Semi-finished alloys that meet the design specifications, have a bright and dense structure, and are free of oxidation defects are crushed to a particle size of 0-0.3mm using a crusher.

[0106] The third step involves producing a molybdenum-vanadium-aluminum-chromium-iron master alloy using a radio frequency plasma spheroidization process.

[0107] Turn on the radio frequency plasma spheroidization system, open the gas supply system, and fill the equipment with high-purity argon gas at a flow rate of 20 L / min. -1 Inflation time: 10 min; Open the sheath gas valve and fill with high-purity helium at a flow rate of 60 L / min. -1 The inflation time is 6 minutes. Once the gas in all chambers is flowing continuously and stably, turn on the high-frequency power supply (40kW). After a stable high-temperature plasma torch flame is generated, start the carrier gas feeding at a rate of 100 g / min. -1 ;

[0108] After the material is completely fed into the reaction chamber by the carrier gas system and the primary alloy powder of molybdenum-vanadium-aluminum-chromium-iron is melted and spheroidized into finer alloy powder, the system is shut off and cooled for 3 hours. The spheroidized powder is then collected to obtain the intermediate alloy of molybdenum-vanadium-aluminum-chromium-iron.

[0109] The chemical composition analysis of the molybdenum-vanadium-aluminum-chromium-iron master alloy prepared in this embodiment was performed, and the results are shown in Table 1. The melting point of the molybdenum-vanadium-aluminum-chromium-iron master alloy prepared in this embodiment is 1511℃, and the density is 4.95 g·cm³. -3 .

[0110] The chemical composition of the molybdenum-vanadium-aluminum-chromium-iron master alloy composite sample in this invention is shown in Table 1:

[0111] Table 1. Main elemental composition of the molybdenum-vanadium-aluminum-chromium-iron master alloys in various embodiments

[0112]

[0113] The particle size distribution of the molybdenum-vanadium-aluminum-chromium-iron master alloy powder prepared in the embodiments of the present invention was analyzed, and the results are shown in Table 2.

[0114] Table 2. Particle size distribution of molybdenum-vanadium-aluminum-chromium-iron master alloy powder in various embodiments

[0115]

[0116] Analysis of the experimental data in Tables 1 and 2 shows that the composition of the alloy powder meets expectations, the particle size is fine and uniform and there are no excessively large particles, which verifies the reliability and quality stability of the preparation process of this invention.

[0117] Comparative Example

[0118] The advantage of this invention lies in its ability to remove impurities and refine the molybdenum-vanadium-aluminum-chromium-ferroalloy prepared by a one-step method, thereby improving powder uniformity. Therefore, the comparative example uses the primary molybdenum-vanadium-aluminum-chromium-ferroalloy prepared by aluminothermic reduction reaction in Example 1, which is then crushed into powder using a conventional mechanical crushing method. The intermediate alloy powder after powdering was subjected to comprehensive chemical composition analysis, and the particle size analysis was also performed. The results are shown in the table below. The comparative alloy has a melting point of 1503℃ and a density of 4.87 g·cm³. -3 .

[0119] Table 3. Main elemental chemical composition of comparative master alloys after powder preparation

[0120]

[0121] Table 4. Particle size distribution analysis of comparative master alloys after powder preparation

[0122]

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 molybdenum-vanadium-aluminum-chromium-iron master alloy, characterized in that, It includes the following components by mass percentage: Mo: 27%-34%, V: 24%-30%, Al: 24%-36%, Cr: 3%-8%, Fe: 4%-8%, and unavoidable impurities.

2. The molybdenum-vanadium-aluminum-chromium-iron master alloy according to claim 1, characterized in that, The molybdenum-vanadium-aluminum-chromium-iron master alloy has a melting point of 1500℃-1520℃ and a density of 4.90 g·cm³. -3 -5.00g·cm -3 .

3. The molybdenum-vanadium-aluminum-chromium-iron master alloy according to claim 1, characterized in that, The particle size D90 of the molybdenum-vanadium-aluminum-chromium-iron master alloy is 0.010mm-0.050mm.

4. A method for preparing the molybdenum-vanadium-aluminum-chromium-ferroalloy master alloy according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Mix molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide, and aluminum powder in a mass ratio of (0.550-0.600):(0.620-0.670):(0.105-0.120):(0.100-0.110):1, add the mixture to a reaction crucible, ignite the reaction, and react at a temperature of 2100℃-2200℃ for 30s-45s to obtain a primary alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy. Step 2: Crush the molybdenum-vanadium-aluminum-chromium-iron primary alloy to obtain molybdenum-vanadium-aluminum-chromium-iron primary alloy powder; Step 3: Using the aforementioned molybdenum-vanadium-aluminum-chromium-iron primary alloy powder as raw material, a molybdenum-vanadium-aluminum-chromium-iron intermediate alloy is produced using radio frequency plasma spheroidization technology.

5. The method for preparing the molybdenum-vanadium-aluminum-chromium-iron master alloy according to claim 4, characterized in that, Before step 1, molybdenum trioxide, vanadium pentoxide, chromium trioxide, ferric oxide and aluminum powder are dried in a constant temperature drying room at 50℃-60℃ for 22h-24h to ensure that the moisture content of the reaction materials is ≤0.1% and the initial temperature is 40℃-50℃.

6. The method for preparing the molybdenum-vanadium-aluminum-chromium-iron master alloy according to claim 4, characterized in that, Before crushing in step 2, the molybdenum-vanadium-aluminum-chromium-iron primary alloy is ground and cleaned.

7. The method for preparing the molybdenum-vanadium-aluminum-chromium-iron master alloy according to claim 4, characterized in that, Step 3, using the aforementioned molybdenum-vanadium-aluminum-chromium-ferroalloy primary alloy powder as raw material, employs radio frequency plasma spheroidization technology to produce a master alloy of molybdenum-vanadium-aluminum-chromium-ferroalloy as follows: First, turn on the gas supply system and fill the equipment with high-purity argon gas as the working gas, controlling the flow rate at 15 L·min. -1 Up to 20 L·min -1 Continue for 5 to 10 minutes to establish the desired atmosphere; Then, the sheath gas valve was opened, and high-purity helium was introduced at a flow rate of 40 L / min. -1 -60 L·min -1 Inflation time: 5-6 minutes; Turn on the high-frequency power supply and set the power to 25 kW-40 kW to generate a high-temperature plasma torch flame; After the plasma torch flame stabilizes, the carrier gas argon is started to transport the primary alloy powder of molybdenum-vanadium-aluminum-chromium-iron at a rate of 40 g·min. -1 -100 g·min -1 The primary alloy powder of molybdenum-vanadium-aluminum-chromium-iron carried by the carrier gas is melted into droplets in the high-temperature reaction chamber and then enters the cooling chamber. Under the combined action of the argon atmosphere and the auxiliary water cooling system in the cooling chamber, the molten droplets are cooled, solidified, and spheroidized to prepare the intermediate alloy of molybdenum-vanadium-aluminum-chromium-iron.

8. The method for preparing the molybdenum-vanadium-aluminum-chromium-iron master alloy according to claim 7, characterized in that, The pressure inside the high-temperature reaction chamber is 1.5 Pa to 2.5 Pa.

9. The application of the molybdenum-vanadium-aluminum-chromium-iron master alloy according to any one of claims 1-3 in the field of TC18 titanium alloy.

10. The application according to claim 9, characterized in that, The mass ratio of molybdenum-vanadium-aluminum-chromium-iron master alloy to Ti in the TC18 titanium alloy is 0.195-0.200:1.

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