A method for preparing aluminum-based intermediate alloy for titanium with high yield

Abstract

The application discloses a preparation method of an aluminum-based intermediate alloy for titanium with a high finished product rate, and comprises the following steps: preparing a block material with a core-shell structure by adopting an isostatic pressing process by using a powdery metal oxide and an aluminum block; the core is the aluminum block, and the shell is the metal oxide; drying the block material in an oven, and the drying temperature is 100-120 DEG C; stacking the dried block material in a crucible, and uniformly covering an aluminum powder layer on the top layer; igniting the aluminum powder to make the material in the crucible perform an aluminum thermal reduction reaction layer by layer, obtaining a molten aluminum-based alloy after the reaction, and taking out the finished product after cooling. The application reduces the specific surface area of raw aluminum, and further reduces the content of Al2O3, so that the oxygen content in the product is reduced; the layer-by-layer reaction reduces the reaction spattering, improves the finished product rate of the product, and the formed block material with the core-shell structure is convenient to use, does not produce dust when feeding, and greatly improves the working environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intermediate alloy for titanium, and particularly relates to a preparation method of aluminum-based intermediate alloy for titanium with high finished product rate. BACKGROUND

[0002] The manufacturing of titanium alloy cannot be separated from the intermediate alloy for titanium. By adding different types of intermediate alloy for titanium, titanium alloys with different performance can be obtained. Common intermediate alloy for titanium can be divided into aluminum-based intermediate alloy for titanium (vanadium-aluminum alloy, molybdenum-aluminum alloy, niobium-aluminum alloy, chromium-aluminum alloy, etc.) and nickel-based intermediate alloy for titanium (nickel-molybdenum alloy, nickel-tungsten alloy, nickel-sulfur alloy, etc.). Among them, the aluminum-based intermediate alloy for titanium is usually prepared by one-step method, that is, using aluminum as a reducing agent to reduce metal oxides to obtain aluminum-based intermediate alloy for titanium.

[0003] The method has low production cost and simple process, but the traditional raw materials are mostly powder and flaky mixtures. During mixing and reaction, a large amount of industrial dust is generated, causing material waste. At the same time, the powder-shaped raw materials have a large specific surface area, and the surface oxides will increase the combined oxygen content of the finished product, reducing the product quality and making it difficult to meet the application of high-end market.

[0004] Taking vanadium-aluminum alloy as an example, vanadium-aluminum (AlV) alloy is an essential material for preparing high-temperature and high-strength titanium alloy materials. Its quality directly affects the comprehensive performance of titanium alloy materials. Its process usually adopts aluminum thermal method, that is, using aluminum (Al) to reduce powder and flaky vanadium pentoxide (V2O5) to prepare vanadium-aluminum alloy. During the mixing and loading process, industrial dust is generated, which is harmful to health and causes waste of raw materials. In addition, the raw materials have a large specific surface area, resulting in high oxygen content of the finished product, and there are many oxide films, which affect the product quality. The common methods for inhibiting oxidation are vacuum melting method and argon atmosphere protection melting, which have high requirements for the sealing property of the production device, and are not suitable for industrialized scale production. SUMMARY

[0005] In order to solve the above problems in the prior art, the application provides a preparation method of aluminum-based intermediate alloy for titanium with high finished product rate. The technical problems to be solved by the application are solved by the following technical scheme:

[0006] The preparation method of aluminum-based intermediate alloy for titanium with high finished product rate comprises the following steps:

[0007] Step 1: using isostatic pressing process to prepare a block material with "core-shell" structure from powder-shaped metal oxides and aluminum blocks; wherein the "core" is aluminum blocks and the "shell" is metal oxides, and the metal oxides are coated around the aluminum blocks;

[0008] Step 2: drying the block material in an oven, and the drying temperature is 100-120 DEG C.

[0009] Step 3: stack the dried block materials in the crucible, and evenly cover a layer of aluminum powder on the top layer;

[0010] Step 4: ignite the aluminum powder, so that the materials in the crucible undergo aluminum thermal reduction reaction layer by layer, and the aluminum-based alloy in molten state is obtained after the reaction, and the finished product is obtained after cooling.

[0011] Further, in step 1, a layer of powdered metal oxide is first added in the isostatic pressing mold, then an aluminum block is placed in the center of the layer of powdered metal oxide, and finally a layer of powdered metal oxide is added to completely cover the aluminum block, and the aluminum block is ensured to be located in the center of the powdered metal oxide.

[0012] Further, in step 3, the block materials are stacked layer by layer.

[0013] Further, the thickness of the aluminum powder is 1-2 mm.

[0014] Advantages of the present application:

[0015] 1. Compared with the existing mixing method, the present application uses aluminum beans, thereby reducing the specific surface area of raw aluminum, further reducing the content of Al2O3, and further reducing the oxygen content in the product, and the formed "core-shell" structure block material is convenient to use, does not produce dust during feeding, greatly improves the working environment, and protects the health of the operators.

[0016] 2. The block materials are stacked and reacted layer by layer in a matrix, which can effectively control the reaction process, reduce the reaction spatter, improve the yield of the product, and reduce the manufacturing cost.

[0017] 3. Compared with the vacuum melting technology, the present application does not involve the use of vacuum equipment, has no requirement for the air tightness of the reaction device, does not change the existing production device, and has low process optimization cost; compared with the argon atmosphere protection technology, the present application does not involve the protection atmosphere device and pressure device, does not need to install the gas atmosphere protection cover, can be carried out in the atmospheric environment, does not change the existing production device, and has low process optimization cost.

[0018] The present application will be further described in detail in combination with the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic diagram of the block material structure after isostatic pressing;

[0020] Figure 2 is a schematic diagram of the block material stacked layer by layer in Example 1;

[0021] Figure 3A schematic diagram of the layer-by-layer stacking of the block for Example 2;

[0022] Figure 4 Test report of the AlV55 alloy prepared for Example 1;

[0023] Figure 5 Test report of the AlMo60 alloy prepared for Example 2.

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] 1-aluminum bean; 2-metal oxide (vanadium pentoxide or molybdenum trioxide); 3-aluminum powder. DETAILED DESCRIPTION

[0026] The present application will be further described in detail below with reference to specific examples, but the embodiments of the present application are not limited thereto. Figures 1-5 The present application will be further described in detail below with reference to specific examples, but the embodiments of the present application are not limited thereto.

[0027] Example 1

[0028] The present application provides a preparation method of an AlV55 alloy for titanium with a high finished product rate, which specifically comprises the following steps:

[0029] Step 1: using powdered vanadium pentoxide and aluminum beans as raw materials; specifically, vanadium pentoxide and 1 aluminum bean are weighed according to a mass ratio of 1.12:1, a layer of powdered vanadium pentoxide is first added in the die of an isostatic pressing machine, then 1 aluminum bean is placed in the center of the layer of powdered vanadium pentoxide, and finally a layer of powdered vanadium pentoxide is added to completely cover the aluminum bean and ensure that the aluminum bean is located at the central position of the powdered vanadium pentoxide, and then isostatic pressing is performed for several times to form a plurality of block materials with a "core-shell" structure, as shown in FIG. 1, wherein the "core" is an aluminum bean and the "shell" is vanadium pentoxide, and the vanadium pentoxide is coated around the aluminum bean. Figure 1

[0030] Step 2: the block material obtained in step 1 is placed in an oven for drying, and the drying temperature is 100-120°C.

[0031] Step 3: the dried block material is stacked layer by layer in a crucible, as shown in FIG. 2, and aluminum powder is uniformly sprayed on the topmost layer, and the thickness of the aluminum powder is 1-2 mm. The 1-2 mm thick aluminum powder can ensure that the aluminothermic reduction reaction proceeds normally and does not affect the content of Al element in the final AlV55 alloy. Figure 2

[0032] ​​Step 4: Use Mg strips as ignition initiators to ignite the aluminum powder on the top layer of the crucible, causing the material inside the crucible to undergo an aluminothermic reduction reaction. This reaction proceeds in a matrix-like, layer-by-layer manner. First, the aluminum powder melts and reacts the vanadium pentoxide on the surface layer. The heat generated then melts the aluminum granules and vanadium pentoxide in the same layer together, causing an aluminothermic reduction reaction. Similarly, the heat from this layer melts the aluminum granules and vanadium pentoxide in the lower layer together, and so on, until the material inside the crucible has completely reacted, resulting in a molten AlV55 alloy. After cooling, it is removed from the crucible.

[0033] The same method was used for three production runs. After each test, the AlV55 alloy was polished and X-rayed. If it passed the test, it was crushed, sieved, mixed, and batched. Then, samples were taken for chemical composition analysis. If the analysis passed, it was packaged.

[0034] Control group 1

[0035] This control group 1 provides a conventional preparation method for AlV55 alloy, specifically including the following steps:

[0036] Step 1: Weigh 132 kg of V2O5 and 118 kg of Al chips, mix them evenly to obtain the aluminothermic reduction reaction mixture.

[0037] Step 2: Add the aluminothermic reduction reaction mixture into a graphite crucible, and use Mg strip as an ignition agent to ignite the surface of the aluminothermic reduction reaction mixture to carry out the aluminothermic reduction reaction. After the aluminothermic reduction reaction is completed, the molten AlV55 alloy is obtained.

[0038] Step 3: After the reaction is complete and the alloy in the crucible has cooled naturally, the cooled AlV55 alloy block is removed from the crucible, its surface is sandblasted, and then chemical composition analysis is performed. The chemical composition analysis results of Example 1 and Control Group 1 are shown in Table 1 and... Figure 4 As shown.

[0039] Table 1. Chemical composition of the AlV55 alloys generated in Example 1 and Control Group 1.

[0040]

[0041] Example 2

[0042] This invention provides a method for preparing a high-yield AlMo60 alloy for titanium, specifically including the following steps:

[0043] Step 1 uses powdered molybdenum trioxide and aluminum beans as raw materials for production; specifically, the molybdenum trioxide and 1 aluminum bean are weighed according to a mass ratio of 1.18:1, a layer of powdered molybdenum trioxide is first added in the mold of an isostatic press, then 1 aluminum bean is placed in the center of the layer of powdered molybdenum trioxide, and finally another layer of powdered molybdenum trioxide is added to completely cover the aluminum bean and ensure that the aluminum bean is located in the central position of the powdered molybdenum trioxide, and then several times of isostatic pressing is performed to form several block materials with a "core-shell" structure, as shown in Figure 1 , wherein the "core" is an aluminum bean and the "shell" is molybdenum trioxide, and the molybdenum trioxide is coated around the aluminum bean.

[0044] Step 2: The block material obtained in Step 1 is placed in an oven for drying, and the drying temperature is 100-120°C.

[0045] Step 3: The dried block material is stacked layer by layer in a crucible, as shown in Figure 3 , and aluminum powder is uniformly sprayed on the top layer, with a thickness of 1-2mm. The 1-2mm thickness of aluminum powder can ensure that the aluminothermic reduction reaction proceeds normally and does not affect the Al element content in the final AlMo60 alloy.

[0046] Step 4: Use Mg strip as an ignition igniter to ignite the aluminum powder on the top layer of the crucible, so that the materials in the crucible undergo aluminothermic reduction reaction, which proceeds in a matrix manner layer by layer; the surface layer of molybdenum trioxide is first melted and reacted by the aluminum powder, and the heat generated melts and causes aluminothermic reduction reaction of the aluminum beans and molybdenum trioxide in the same layer, and the same principle applies to the heat of this layer, which melts the aluminum beans and molybdenum trioxide in the lower layer, and so on, until the reaction of the materials in the crucible is completed, obtaining the AlMo60 alloy in a molten state, which is removed from the crucible after cooling.

[0047] The same method is used to produce three times, and then the AlMo60 alloy after each test is polished and subjected to X-ray detection, and after passing the detection, it is subjected to crushing, screening, mixing, batching, and then sampling for chemical composition analysis, and after passing the analysis, it is packaged.

[0048] Control group 2

[0049] The control group 2 provides a conventional preparation method of AlMo60 alloy, specifically including the following steps:

[0050] Step 1: Mix 100 kg of high-purity molybdenum trioxide powder, 81 kg of high-purity aluminum powder, and 57 kg of high-purity fluorite powder uniformly to obtain an aluminothermic reduction reaction mixture.

[0051] Step 2: The aluminum thermal reduction reaction mixture is added into a graphite crucible, and a Mg strip is used as an ignition agent to ignite the surface of the aluminum thermal reduction reaction mixture, and the aluminum thermal reduction reaction is carried out. After the aluminum thermal reduction reaction is completed, the obtained molten AlMo60 alloy is obtained.

[0052] Step 3: After the reaction is completed, the alloy in the crucible is naturally cooled, and the cooled AlMo60 alloy block is taken out of the crucible. After the surface layer is sandblasted, chemical composition analysis is performed. The chemical composition analysis results of Example 2 and Control Group 2 are shown in Table 2 and Figure 5

[0053] Table 2 Chemical composition of the AlMo60 alloy generated in Example 2 and Control Group 2

[0054]

[0055] The above is a further detailed description of the present application in combination with specific preferred embodiments, and cannot be considered as limiting the specific implementation of the present application to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, a number of simple deductions or substitutions can be made without departing from the concept of the present application, and all of them should be considered as falling within the protection scope of the present application.​

Claims

1. A method for preparing an aluminum-based master alloy for titanium with high yield, characterized in that, include: Step 1: The powdered metal oxide and aluminum granules are prepared into a block with a "core-shell" structure using an isostatic pressing process; wherein the "core" is the aluminum granule and the "shell" is the metal oxide, and the metal oxide covers the aluminum granule; the metal oxide is vanadium pentoxide or molybdenum trioxide; Step 2: Dry the block material in an oven at a temperature of 100~120℃; Step 3: Stack the dried blocks in the crucible and evenly cover the top layer with a layer of aluminum powder; the blocks are stacked layer by layer. Step 4: Ignite the aluminum powder to allow the materials in the crucible to undergo aluminothermic reduction reaction layer by layer. After the reaction is complete, a molten aluminum-based alloy is obtained. After cooling, the finished product is obtained.

2. The method for preparing high-yield aluminum-based master alloys for titanium according to claim 1, characterized in that, In step 1, a layer of powdered metal oxide is first added to the isostatic press mold, then an aluminum bead is placed in the center of the powdered metal oxide layer, and finally another layer of powdered metal oxide is added to completely cover the aluminum bead, ensuring that the aluminum bead is located in the center of the powdered metal oxide layer.

3. The method for preparing high-yield aluminum-based master alloys for titanium according to claim 2, characterized in that, The thickness of the aluminum powder is 1~2mm.

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