Aluminum-tungsten-titanium intermediate alloy and preparation method and application thereof

Abstract

The invention provides an aluminum-tungsten-titanium intermediate alloy and a preparation method and application thereof, and the preparation method comprises the following steps: mixing an aluminum simple substance, titanium dioxide, a tungsten source, a flux and a heat generating agent, igniting in a graphite molten pool by using an ignition agent to carry out an aluminothermic reaction, and cooling after the aluminothermic reaction is finished to obtain the aluminum-tungsten-titanium intermediate alloy, the graphite molten pool is a hollow reaction cavity formed by a graphite material. According to the preparation method, the segregation phenomenon caused by the metal melting point difference of the aluminum-tungsten-titanium intermediate alloy is avoided, the difference value of the W content is controlled to be within 0.74 wt%, the difference value of the Ti content is controlled to be 0.77 wt%, the component uniformity of the alloy is remarkably improved, the preparation method can be used for preparing the high-tungsten-content intermediate alloy with the tungsten content being 60 wt% or above, the method is simple and convenient, and the cost is low. The production efficiency is high.

Description

Technical Field

[0001] The invention belongs to the technical field of metal materials and relates to a master alloy, in particular to an aluminum-tungsten-titanium master alloy and a preparation method and application thereof. Background Art

[0002] As an alloy material with high strength and excellent stability, high-temperature titanium alloys have been widely used in many fields such as aerospace, medical treatment, etc. As an important raw material for the preparation of titanium alloys, aluminum-tungsten alloys can significantly increase the heat resistance and creep resistance of titanium alloys, and have a significant position in the field of high-temperature titanium alloys. Among aluminum-tungsten alloys, aluminum-tungsten alloys are extremely difficult to synthesize using the aluminothermic method because the melting point difference between aluminum and tungsten is too large, and tungsten has not melted when aluminum reaches the boiling point. However, when titanium is added, it will promote the combination of aluminum and tungsten, so the preparation of aluminum-tungsten-titanium intermediate alloys is of great significance.

[0003] The common production method of aluminum-tungsten-titanium master alloy is the off-furnace ignition smelting method. This method uses Al as a reducing agent, WO3 and TiO2 as oxidants in an open environment, and utilizes the spontaneous heat generated by the metal thermal reduction reaction process to achieve the smelting of the master alloy.

[0004] CN101545065A discloses an aluminum-tungsten-titanium master alloy and a preparation method thereof, wherein the aluminum-tungsten-titanium master alloy is composed of: Al 40-47wt%, Ti 8-13wt%, and the balance is W, and is prepared by self-propagating smelting using Al, WO3, TiO2, and CaF2 as raw materials. During the preparation of the aluminum-tungsten alloy, there is a large density difference and melting point difference between aluminum and refractory metal tungsten. After the aluminothermic reaction occurs, segregation will occur in the molten state, resulting in poor uniformity of the final alloy product. At the same time, due to the difference in physical properties between aluminum and tungsten, it is difficult to further increase the tungsten content in the aluminum-tungsten alloy, and it is impossible to meet the use requirements of alloys with high tungsten content.

[0005] CN117344191A discloses a method for producing an aluminum-tungsten-tantalum ternary master alloy, wherein tantalum pentoxide, aluminum powder and potassium chlorate are first subjected to aluminothermic reaction to obtain a tantalum-aluminum alloy ingot, which is then turned into chips and then subjected to vacuum aluminothermic reaction with tungsten trioxide and aluminum powder to prepare an aluminum-tungsten-tantalum alloy, thereby improving the uniformity of the alloy. However, the process flow of this method is relatively complicated and needs to be optimized.

[0006] Based on the above problems in the prior art, the present invention provides a method for preparing an aluminum-tungsten-titanium intermediate alloy with a simple process and improved alloy uniformity. Summary of the invention

[0007] The purpose of the present invention is to provide an aluminum-tungsten-titanium master alloy and a preparation method and application thereof, so as to improve the composition uniformity of the aluminum-tungsten-titanium master alloy and solve the segregation problem existing in the preparation of master alloys from aluminum and high melting point metals, with simple process and high production efficiency.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing an aluminum-tungsten-titanium master alloy, the preparation method comprising:

[0010] Aluminum, titanium dioxide, tungsten source, flux and heating agent are mixed, ignited with an igniter in a graphite molten pool to perform a thermite reaction, and after the thermite reaction is completed, the mixture is cooled to obtain an aluminum-tungsten-titanium master alloy;

[0011] The graphite molten pool is formed of a graphite material to form a hollow reaction chamber.

[0012] The preparation method provided by the present invention is based on the off-furnace ignition smelting method for alloy preparation, uses graphite material to form a molten pool, and conducts an aluminothermic reaction in the reaction raw materials, and utilizes the specific thermal conductivity and thermal shock resistance of the graphite material to cool the alloy during the preparation process, while solving the segregation phenomenon caused by the difference in metal melting points in the aluminum-tungsten-titanium master alloy, improving the uniformity of the alloy composition, and at the same time, compared with the prior art, can improve the tungsten content of the aluminum-tungsten-titanium master alloy. The preparation method is simple, low-cost, and high in production efficiency.

[0013] Preferably, the tungsten source comprises CaWO4 and / or WO3, preferably CaWO4.

[0014] In the present invention, when CaWO4 is used as the tungsten source, the slag system after the aluminothermic reaction includes CaO, CaF2 and Al2O3. The three work together during the reaction process to allow the gas to escape well, thereby reducing the alloy stratification phenomenon and the thickness of the loose layer.

[0015] Preferably, when the tungsten source is CaWO4, the mass ratio of CaWO4 to titanium dioxide is 1:(0.15-0.25), for example, it can be 1:0.15, 1:0.16, 1:0.17, 1:0.18, 1:0.19, 1:0.20, 1:0.21, 1:0.22, 1:0.23, 1:0.24 or 1:0.25, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, when the tungsten source is CaWO4, the mass ratio of CaWO4 to aluminum is 1:(0.5-0.7), for example, it can be 1:0.5, 1:0.55, 1:0.6, 1:0.65 or 1:0.7, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, when the tungsten source is CaWO4, the mass ratio of CaWO4 to flux is 1:(0.06-0.1), for example, it can be 1:0.06, 1:0.07, 1:0.08, 1:0.09 or 1:0.1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, when the tungsten source is CaWO4, the mass ratio of CaWO4 to the heating agent is 1:(0.15-0.25), for example, it can be 1:0.15, 1:0.16, 1:0.17, 1:0.18, 1:0.19, 1:0.20, 1:0.21, 1:0.22, 1:0.23, 1:0.24 or 1:0.25, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, when the tungsten source is WO3, the mass ratio of WO3 to titanium dioxide is 1:(0.2-0.3), for example, it can be 1:0.2, 1:0.22, 1:0.25, 1:0.28 or 1:0.3, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, when the tungsten source is WO3, the mass ratio of WO3 to aluminum is 1:(0.75-0.85), for example, it can be 1:0.75, 1:0.78, 1:0.8, 1:0.82 or 1:0.85, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, when the tungsten source is WO3, the mass ratio of WO3 to flux is 1:(0.28-0.35), for example, it can be 1:0.28, 1:0.30, 1:0.32, 1:0.34 or 1:0.35, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, when the tungsten source is WO3, the mass ratio of WO3 to the heating agent is 1:(0.15-0.22), for example, it can be 1:0.15, 1:0.16, 1:0.18, 1:0.20 or 1:0.22, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the flux comprises CaF2.

[0024] Preferably, the exothermic agent includes any one of Ca(ClO3)2, NaClO3 or KClO3 or a combination of at least two of them. Typical but non-limiting combinations include a combination of Ca(ClO3)2 and NaClO3, a combination of NaClO3 and KClO3, a combination of Ca(ClO3)2 and KClO3, or a combination of Ca(ClO3)2, NaClO3 and KClO3.

[0025] Preferably, the igniter comprises magnesium strips.

[0026] Preferably, the graphite material comprises impregnated graphite.

[0027] In the present invention, impregnated graphite is used, which can meet certain shock resistance and can be used for multiple productions. At the same time, pores formed in the alloy by graphite combustion are reduced, and the introduction of carbon impurity elements is avoided.

[0028] Preferably, the bulk density of the impregnated graphite is ≥1.75 g / cm 3 , for example, it can be 1.75 g / cm 3 , 1.78g / cm 3 , 1.80g / cm 3 , 1.85g / cm 3 , 1.90g / cm 3 , 2.0g / cm 3 , 2.5g / cm 3 、3.0g / cm 3 , 4.0g / cm 3 or 5.0g / cm 3 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the total porosity of the impregnated graphite is 10-19%, for example, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% or 19%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] In the present invention, the production method of impregnated graphite comprises: kneading graphite aggregate and binder, performing first roasting, performing first impregnation with impregnating agent after roasting, performing second roasting after impregnation, and then performing second impregnation, third roasting, third impregnation and fourth roasting in sequence, and finally machining and forming.

[0031] Preferably, the thickness of the reaction chamber is 25-30 mm, for example, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm or 30 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] Preferably, in the graphite molten pool, a graphite intermediate layer is arranged to form at least two reaction chambers.

[0033] Preferably, the thickness of the graphite material between adjacent reaction chambers is 30-50 mm, for example, 30 mm, 32 mm, 35 mm, 38 mm, 40 mm, 42 mm, 45 mm, 48 mm or 50 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the leakage port of the graphite molten pool is covered with an aluminum sheet.

[0035] Preferably, the thickness of the aluminum sheet is 0.5-2 mm, for example, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm or 2 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the mixing process includes feeding, mixing and discharging.

[0037] Preferably, the mixing is performed using a mixer.

[0038] Preferably, the feed rotation speed is 4-6 r / min, for example, it can be 4 r / min, 4.5 r / min, 5 r / min, 5.5 r / min or 6 r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the mixing speed is 18-22 r / min, for example, 18 r / min, 19 r / min, 20 r / min, 21 r / min or 22 r / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] Preferably, the mixing time is 3min55s to 4min05s, for example, 3min55s, 3min58s, 4min, 4min02s or 4min05s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, the unloading rotation speed is 6-8r / min, for example, it can be 6r / min, 6.5r / min, 7r / min, 7.5r / min or 8r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, before the mixing, the aluminum element, titanium dioxide, tungsten source, flux and heating agent are dried separately.

[0043] Preferably, the drying temperature is 110-130°C, for example, 110°C, 115°C, 120°C, 125°C or 130°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, the drying time is ≥12 h, for example, it can be 12 h, 15 h, 18 h, 20 h, 25 h, 30 h, 40 h or 50 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the cooling time is ≥ 20 h, for example, it can be 20 h, 22 h, 25 h, 28 h, 30 h, 35 h, 40 h or 50 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In a second aspect, the present invention provides an aluminum-tungsten-titanium master alloy, wherein the aluminum-tungsten-titanium master alloy is prepared by the preparation method described in the first aspect.

[0047] Preferably, the composition of the aluminum-tungsten-titanium master alloy is, in terms of mass percentage, W 60.0-63.0wt%, Ti 9-11wt%, and the remainder is Al and inevitable impurities; the inevitable impurities include: O≤0.10wt%, N≤0.05wt%, Fe≤0.08wt%, Si≤0.15wt%, and C≤0.02wt%.

[0048] Among them, the W content of the aluminum-tungsten-titanium master alloy is 60.0-63.0wt%, for example, it can be 60.0wt%, 60.5wt%, 61.0wt%, 61.5wt%, 62.0wt%, 62.5wt% or 63.0wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] The Ti content of the aluminum-tungsten-titanium master alloy is 9-11wt%, for example, 9wt%, 9.5wt%, 10wt%, 10.5wt% or 11wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] In a third aspect, the present invention provides an application of the aluminum-tungsten-titanium master alloy described in the second aspect, wherein the aluminum-tungsten-titanium master alloy is used to prepare a titanium alloy.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The preparation method provided by the present invention solves the segregation phenomenon caused by the difference in metal melting points of the aluminum-tungsten-titanium master alloy, controls the difference in W content to within 0.74wt%, controls the difference in Ti content to 0.77wt%, significantly improves the composition uniformity of the alloy, and can be used to prepare a high-tungsten master alloy with a tungsten content of more than 60wt%. The method is simple and has high production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a schematic diagram of the cross-sectional structure of a multi-cavity graphite molten pool provided in Example 1;

[0054] Figure 2 is a schematic structural diagram of a melt pool layer plate of a multi-cavity graphite melt pool provided in Example 1;

[0055] Figure 3 It is a schematic structural diagram of a melt pool side plate of a multi-cavity graphite melt pool provided in Example 1;

[0056] Among them: 1-molten pool layer plate; 2-molten pool side plate; 3-molten pool bottom plate; 4-reaction chamber; 11-protrusion; 12-leakage port; 21-groove. DETAILED DESCRIPTION

[0057] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0058] Example 1

[0059] This embodiment provides a method for preparing an aluminum-tungsten-titanium master alloy.

[0060] In this embodiment, a multi-cavity graphite molten pool is built in the furnace.

[0061] like Figure 1-3 As shown, the multi-cavity graphite molten pool comprises:

[0062] Molten pool layer plate 1, molten pool side plate 2 and molten pool bottom plate 3.

[0063] A protrusion 11 is provided on the side of the molten pool layer plate 1, and a groove 21 is provided on a side plane of the molten pool side plate 2. The protrusion 11 cooperates with the groove 21 to form a plug-in structure.

[0064] A liquid leakage port 12 is provided at a top corner of the molten pool layer plate 1 .

[0065] On the molten pool bottom plate 3, the molten pool layer plate 1 and the molten pool side plate 2 are spliced ​​through a plug-in structure to form a multi-cavity graphite molten pool.

[0066] A hollow reaction chamber is formed between the molten pool layers 1 and between the molten pool layers 1 and the molten pool bottom plate 3 .

[0067] The number of the molten pool layers 1 is three, forming four reaction chambers 4 .

[0068] The thickness of the reaction chamber 4 is 30 mm.

[0069] The thickness of the molten pool layer 1 is 40 mm.

[0070] The liquid leakage port 12 of the molten pool layer plate 1 is covered with an aluminum sheet with a thickness of 1 mm to prevent the material from leaking into the lower cavity of the molten pool, causing waste of material and pollution to the alloy.

[0071] The material of the molten pool layer plate 1, the molten pool side plate 2 and the molten pool bottom plate 3 is impregnated graphite, and the bulk density of the impregnated graphite is 1.75g / cm 3 , the total porosity is 19%.

[0072] The space between the melting furnace and the multi-cavity graphite melting pool is filled with slag.

[0073] The preparation method comprises the following steps:

[0074] (1) 385 kg of CaWO4, 78.2 kg of TiO2, 254.1 kg of Al, 31.3 kg of CaF2 and 78.2 kg of NaClO3 were dried respectively, and then mixed evenly using a mixer, the rotation speed of the mixer was 20 r / min, and the mixing time was 4 min to obtain a mixed material, wherein the mass ratio of CaWO4, TiO2, Al, CaF2 and NaClO3 was 1:0.20:0.66:0.08:0.20;

[0075] (2) putting the mixed material into the multi-cavity graphite molten pool, igniting it with a magnesium rod to carry out an aluminothermic reaction, and cooling it with the furnace after the reaction is completed. Cooling for 24 hours to obtain an aluminum-tungsten-titanium master alloy.

[0076] In this embodiment, a total of 4 layers of aluminum-tungsten-titanium master alloy ingots are obtained, with a total ingot weight of 335.4 kg, and an average weight of 83.85 kg per layer.

[0077] For each layer of the aluminum-tungsten-titanium master alloy ingot obtained in this embodiment, one point was selected from the top and the bottom for sampling and analysis. The numbering was in the sampling order. The chemical composition of the obtained sampling points is shown in the following table, and the remainder is Al.

[0078]

[0079] Example 2

[0080] This embodiment provides a method for preparing an aluminum-tungsten-titanium master alloy.

[0081] In this embodiment, the graphite molten pool is a multi-cavity graphite molten pool, and the multi-cavity graphite molten pool is the same as that in Embodiment 1.

[0082] The preparation method comprises the following steps:

[0083] (1) 287 kg of WO3, 71.8 kg of TiO2, 229.6 kg of Al, 86.1 kg of CaF2 and 48.8 kg of KClO3 were dried respectively, and then mixed evenly using a mixer, the rotation speed of the mixer was 20 r / min, and the mixing time was 4 min to obtain a mixed material, wherein the mass ratio of WO3, TiO2, Al, CaF2 and KClO3 was 1:0.25:0.8:0.3:0.17;

[0084] (2) putting the mixed material into the multi-cavity graphite molten pool, igniting it with a magnesium rod to carry out an aluminothermic reaction, and cooling it with the furnace after the reaction is completed. Cooling for 24 hours to obtain an aluminum-tungsten-titanium master alloy.

[0085] In this embodiment, a total of 4 layers of aluminum-tungsten-titanium master alloy ingots are obtained, with a total ingot weight of 338.2 kg, and an average weight of 84.55 kg per layer.

[0086] For each layer of the aluminum-tungsten-titanium master alloy ingot obtained in this embodiment, one point was selected from the top and the bottom for sampling and analysis. The numbering was in the sampling order. The chemical composition of the obtained sampling points is shown in the following table, and the remainder is Al.

[0087]

[0088] Example 3

[0089] This embodiment provides a method for preparing an aluminum-tungsten-titanium master alloy. Compared with Example 1, the mass ratio of CaWO4, TiO2, Al, CaF2 and NaClO3 is controlled to be 1:0.15:0.7:0.06:0.25, and the rest is the same as Example 1.

[0090] In this embodiment, a total of 4 layers of aluminum-tungsten-titanium master alloy ingots are obtained, with a total ingot weight of 336.1 kg, and an average weight of 84.03 kg per layer.

[0091] For each layer of the aluminum-tungsten-titanium master alloy ingot obtained in this embodiment, one point was selected from the top and the bottom for sampling and analysis. The numbering was in the sampling order. The chemical composition of the obtained sampling points is shown in the following table, and the remainder is Al.

[0092]

[0093] Example 4

[0094] This embodiment provides a method for preparing an aluminum-tungsten-titanium master alloy. Compared with Example 1, the mass ratio of CaWO4, TiO2, Al, CaF2 and NaClO3 is controlled to be 1:0.25:0.5:0.1:0.15, and the rest is the same as Example 1.

[0095] In this embodiment, a total of 4 layers of aluminum-tungsten-titanium master alloy ingots are obtained, with a total ingot weight of 337.3 kg, and an average weight of 84.33 kg per layer.

[0096] For each layer of the aluminum-tungsten-titanium master alloy ingot obtained in this embodiment, one point was selected from the top and the bottom for sampling and analysis. The numbering was in the sampling order. The chemical composition of the obtained sampling points is shown in the following table, and the remainder is Al.

[0097]

[0098] Example 5

[0099] This embodiment provides a method for preparing an aluminum-tungsten-titanium master alloy. Compared with Embodiment 1, the thickness of the reaction chamber in the multi-cavity graphite molten pool is set to 40 mm, and the rest is the same as Embodiment 1.

[0100] In this embodiment, a total of 4 layers of aluminum-tungsten-titanium master alloy ingots are obtained, with a total ingot weight of 333.9 kg, and an average weight of 83.48 kg per layer.

[0101] For each layer of the aluminum-tungsten-titanium master alloy ingot obtained in this embodiment, one point was selected from the top and the bottom for sampling and analysis. The numbering was in the sampling order. The chemical composition of the obtained sampling points is shown in the following table, and the remainder is Al.

[0102]

[0103] Example 6

[0104] This embodiment provides a method for preparing an aluminum-tungsten-titanium master alloy. Compared with Embodiment 1, in the multi-cavity graphite molten pool, the thickness of the molten pool layer is 20 mm, and the rest is the same as Embodiment 1.

[0105] In this embodiment, a total of 4 layers of aluminum-tungsten-titanium master alloy ingots are obtained, with a total ingot weight of 337.5 kg, and an average weight of 84.38 kg per layer.

[0106] For each layer of the aluminum-tungsten-titanium master alloy ingot obtained in this embodiment, one point was selected from the top and the bottom for sampling and analysis. The numbering was in the sampling order. The chemical composition of the obtained sampling points is shown in the following table, and the remainder is Al.

[0107]

[0108] Example 7

[0109] This embodiment provides a method for preparing an aluminum-tungsten-titanium master alloy. Compared with Embodiment 1, the material of the multi-cavity graphite molten pool is replaced by graphite instead of impregnated graphite, and the rest is the same as Embodiment 1.

[0110] In this embodiment, a total of 4 layers of aluminum-tungsten-titanium master alloy ingots are obtained, with a total ingot weight of 336.2 kg, and an average weight of 84.05 kg per layer.

[0111] For each layer of the aluminum-tungsten-titanium master alloy ingot obtained in this embodiment, one point was selected from the top and the bottom for sampling and analysis. The numbering was in the sampling order. The chemical composition of the obtained sampling points is shown in the following table, and the remainder is Al.

[0112]

[0113] Comparative Example 1

[0114] This comparative example provides a method for preparing an aluminum-tungsten-titanium master alloy.

[0115] In the preparation method, the graphite molten pool used is composed of a molten pool bottom plate and a molten pool side plate, and a hollow cavity is formed in the molten pool bottom plate and the molten pool side plate, that is, compared with the graphite molten pool in Example 1, no molten pool layer plate is set, and the thickness of the hollow cavity is greater than 120mm.

[0116] The preparation method comprises the following steps:

[0117] (1) 126 kg of WO3, 31.5 kg of TiO2, 100.8 kg of Al, 37.8 kg of CaF2 and 21.4 kg of KClO3 were dried respectively, and then mixed evenly using a mixer, the rotation speed of the mixer was 20 r / min, and the mixing time was 4 min to obtain a mixed material, wherein the mass ratio of WO3, TiO2, Al, CaF2 and KClO3 was 1:0.27:0.8:0.3:0.17;

[0118] (2) The mixed material is put into the graphite molten pool and ignited with a magnesium rod to carry out an aluminothermic reaction. After the reaction is completed, the mixed material is cooled in the furnace for 24 hours to obtain an aluminum-tungsten-titanium intermediate alloy.

[0119] In this comparative example, an aluminum-tungsten-titanium intermediate alloy ingot with an ingot weight of 148.4 kg was obtained.

[0120] The upper, middle and lower points of the aluminum-tungsten-titanium master alloy ingot obtained in this comparative example were sampled and analyzed, and the chemical compositions of the obtained sampling points were shown in the following table, with the remainder being Al.

[0121]

[0122] Comparative Example 2

[0123] This comparative example provides a method for preparing an aluminum-tungsten-titanium master alloy. Compared with Example 1, a multi-cavity quartz molten pool is used, that is, the material of the multi-cavity graphite molten pool is replaced with quartz, and the rest is the same as Example 1.

[0124] In this comparative example, a total of 4 layers of aluminum-tungsten-titanium intermediate alloy ingots were obtained, with a total ingot weight of 328.5 kg, and an average weight of 82.13 kg per layer.

[0125] For each layer of the aluminum-tungsten-titanium master alloy ingot obtained in this comparative example, one point was selected from the top and the bottom for sampling and analysis. The numbering was in the sampling order. The chemical composition of the obtained sampling points is shown in the following table, and the remainder is Al.

[0126]

[0127] The sampling and analysis results of the tungsten-titanium master alloy ingots prepared in the examples and comparative examples, and the calculated chemical composition difference results are summarized in Table 1.

[0128] Table 1

[0129]

[0130]

[0131] It can be seen from Table 1 that the aluminum-tungsten-titanium master alloy prepared by the present invention has good uniformity, small component segregation, and low impurity content, especially the gas impurity content is controlled at an extremely low level, and the alloy purity is high.

[0132] In Examples 1, 3 and 4, a multi-cavity graphite molten pool is used, and the alloy thickness is controlled below 30 mm, which can effectively avoid component segregation. The maximum range of the W element is only 0.74wt%, and the maximum range of the Ti element is only 0.77wt%. The alloy composition has high uniformity. In addition, the molten pool is provided with a multi-cavity structure and the thickness of the intermediate layer is set. Multiple alloy ingots can be produced at the same time, which greatly improves the production efficiency. At the same time, the alloy ingots have good uniformity.

[0133] Compared with Example 1, WO3 is used as the tungsten source in Example 2, and the oxygen and nitrogen levels in the alloy are relatively high. Compared with WO3, when CaWO4 is used, the slag system after the aluminothermic reaction includes CaO, CaF2 and Al2O3. The three work together during the reaction process to allow the gas to escape well, and the oxygen and nitrogen in the alloy are at extremely low levels; in Example 5, the thickness of the alloy ingot is increased, the alloy components show a more obvious segregation, and the content of impurity elements is relatively stable; in Example 6, the thickness of the graphite layer is reduced, which reduces the thermal shock resistance of the graphite layer, resulting in an increase in carbon elements in the alloy; in Example 7, the impregnated graphite is replaced with ordinary graphite, the porosity of the graphite is increased, the thermal shock resistance is deteriorated, resulting in serious graphite burning, and a large amount of carbon enters the alloy, resulting in excessive impurity elements, which is not conducive to use.

[0134] Compared with Example 1, in Comparative Example 1, a reaction chamber is set in the graphite molten pool to prepare a single large-volume alloy ingot, and the thickness and volume of the alloy are greatly increased, which makes the segregation of the alloy extremely serious, and the alloy no longer meets the usage indicators; in Comparative Example 2, quartz will introduce silicon impurities, causing the silicon content of the alloy to increase. At the same time, the thermal conductivity of quartz does not meet the requirements, which prolongs the insulation time, the degree of alloy segregation becomes larger, and the gas phase impurities are high. In addition, the quartz is broken due to severe burning after one use and cannot be reused, which greatly increases the cost.

[0135] In summary, the preparation method provided by the present invention solves the segregation phenomenon of the aluminum-tungsten-titanium master alloy caused by the difference in metal melting points, controls the difference in W content to within 0.74wt%, and controls the difference in Ti content to 0.77wt%, significantly improving the composition uniformity of the alloy, and can be used to prepare a high-tungsten-content master alloy with a tungsten content of more than 60wt%, the method is simple, and the production efficiency is high.

[0136] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an aluminum-tungsten-titanium master alloy, characterized in that: The preparation method comprises: Aluminum, titanium dioxide, tungsten source, flux and heating agent are mixed, ignited with an igniter in a graphite molten pool to carry out a thermite reaction, and after the thermite reaction is completed, the mixture is cooled to obtain an aluminum-tungsten-titanium master alloy; The graphite molten pool is formed of a graphite material to form a hollow reaction chamber.

2. The preparation method according to claim 1, characterized in that: The tungsten source includes CaWO4 and / or WO3; Preferably, when the tungsten source is CaWO4, the mass ratio of CaWO4, titanium dioxide, aluminum, flux and heating agent is 1:(0.15-0.25):(0.5-0.7):(0.06-0.1):(0.15-0.25); Preferably, when the tungsten source is WO3, the mass ratio of WO3, titanium dioxide, aluminum element, flux and heating agent is 1:(0.2-0.3):(0.75-0.85):(0.28-0.35):(0.15-0.22).

3. The preparation method according to claim 1 or 2, characterized in that: The flux includes CaF2; Preferably, the exothermic agent includes any one of Ca(ClO3)2, NaClO3 or KClO3 or a combination of at least two thereof; Preferably, the igniter comprises magnesium strips.

4. The preparation method according to any one of claims 1 to 3, characterized in that The graphite material includes impregnated graphite, and the bulk density of the impregnated graphite is ≥1.75 g / cm 3 , the total porosity of the impregnated graphite is 10-19%; Preferably, the thickness of the reaction chamber is 25-30 mm.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In the graphite molten pool, a graphite intermediate layer is arranged to form at least two reaction chambers; Preferably, the thickness of the graphite material between adjacent reaction chambers is 30-50 mm.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The leakage port of the graphite molten pool is covered with an aluminum sheet; Preferably, the thickness of the aluminum sheet is 0.5-2 mm.

7. The preparation method according to any one of claims 1 to 6, characterized in that: Before the mixing, the aluminum element, titanium dioxide, tungsten source, flux and heating agent are dried respectively; Preferably, the drying temperature is 110-130°C; Preferably, the drying time is ≥12h; Preferably, the cooling time is ≥ 20 h.

8. An aluminum-tungsten-titanium master alloy, characterized in that: The aluminum-tungsten-titanium master alloy is prepared by the preparation method described in any one of claims 1-7.

9. The aluminum-tungsten-titanium master alloy according to claim 8, characterized in that: The composition of the aluminum-tungsten-titanium master alloy is, in terms of mass percentage, 60.0-63.0wt% of W, 9-11wt% of Ti, and the remainder is Al and unavoidable impurities; The unavoidable impurities include: O≤0.10wt%, N≤0.05wt%, Fe≤0.08wt%, Si≤0.15wt%, and C≤0.02wt%.

10. An application of the aluminum-tungsten-titanium master alloy as claimed in claim 8 or 9, characterized in that: The aluminum-tungsten-titanium master alloy is used for preparing titanium alloy.

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