A kind of aviation grade vanadium aluminum alloy and preparation method thereof

Abstract

The present invention provides an aviation-grade vanadium-aluminum alloy and a preparation method thereof, and belongs to the field of alloy technology. The preparation method of the aviation-grade vanadium-aluminum alloy provided by the present invention comprises the following steps: mixing vanadium pentoxide and aluminum particles and then pressing to obtain a mixture sheet; subjecting the mixture sheet to a vacuum aluminothermic reaction under side-blowing argon gas, and then cooling to obtain a vanadium-aluminum alloy ingot with an upper layer of an aluminum oxide layer; the angle between the argon gas pipe of the side-blowing argon gas and the horizontal direction is 30 to 60°; removing the aluminum oxide layer on the upper layer of the vanadium-aluminum alloy ingot to obtain an aviation-grade vanadium-aluminum alloy. The present invention can destroy the high vacuum area by the angle of the side-blowing argon gas during the vacuum aluminothermic reaction, so that the aluminum oxide slag inside the vanadium-aluminum alloy is completely separated from the vanadium-aluminum alloy ingot, and a floating aluminum oxide layer is formed on the surface of the vanadium-aluminum alloy ingot, and at the same time, it is in an argon gas protective atmosphere to ensure that the nitrogen element in the vanadium-aluminum alloy ingot will not increase, thereby reducing the aluminum oxide inclusion content and nitrogen content of the vanadium-aluminum alloy.

Description

Technical Field

[0001] The invention belongs to the technical field of alloys, and in particular relates to an aviation-grade vanadium-aluminum alloy and a preparation method thereof. Background Art

[0002] Vanadium aluminum alloy is an important intermediate alloy for preparing vanadium-containing titanium alloy. The addition of metal vanadium can refine the grains of titanium alloy and thus improve the plasticity of titanium alloy. This property is particularly important for manufacturing complex aerospace components, because these components usually need to work under extreme conditions and have high requirements for the plasticity and strength of the material.

[0003] At present, aviation-grade vanadium-aluminum alloy is mainly prepared by the aluminothermic method. The aluminothermic reaction proceeds from top to bottom, and the heat generated by the reaction above continuously provides activation energy for the reaction of the materials below to ensure that the oxides are completely reduced. This process is affected by density, and alumina moves upward and the alloy moves downward. Since the melting point of alumina is 2050°C, which is much higher than the melting point of vanadium-aluminum alloy, the alumina exposed to the air solidifies first. At this time, the internal aluminothermic reaction has not ended, resulting in the inability to separate the air and furnace gas inside the alloy from the system, forming a high-pressure area between the alumina and the vanadium-aluminum alloy ingot. When the alloy is in a molten state, the surface tension and static pressure of the upper surface in contact with the high-pressure area are too large, making it impossible to separate the alumina slag inside the alloy molten metal from the alloy ingot, and the high vacuum area needs to be destroyed. However, after the upper alumina layer is destroyed by the conventional aluminothermic method, nitrogen will be introduced into the alloy, so that the prepared vanadium-aluminum alloy has more alumina slag, and the nitrogen element is about 0.01wt%. The alloy quality is poor and cannot be used as an aviation-grade vanadium-aluminum alloy for cutting-edge equipment.

[0004] Therefore, in view of the problems of excessive alumina inclusions and high nitrogen content in current aviation-grade vanadium-aluminum alloys, how to reduce the alumina inclusion content and nitrogen content of vanadium-aluminum alloys has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] The purpose of the present invention is to provide an aviation-grade vanadium-aluminum alloy and a preparation method thereof. The preparation method provided by the present invention can produce an aviation-grade vanadium-aluminum alloy with high purity and low nitrogen content.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing aviation-grade vanadium-aluminum alloy, comprising the following steps:

[0008] (1) mixing vanadium pentoxide and aluminum particles and pressing the mixture to obtain a mixture tablet;

[0009] (2) subjecting the mixed sheet obtained in step (1) to a vacuum aluminum thermite reaction under side-blown argon, and then cooling to obtain a vanadium aluminum alloy ingot with an upper layer of an aluminum oxide layer; the angle between the argon pipe of the side-blown argon and the horizontal direction is 30 to 60 degrees;

[0010] (3) removing the aluminum oxide layer on the upper layer of the vanadium aluminum alloy ingot obtained in step (2) to obtain aviation-grade vanadium aluminum alloy.

[0011] Preferably, in step (1), the mass ratio of vanadium pentoxide to aluminum particles is (8-14):(9-10).

[0012] Preferably, the temperature of the side-blown argon gas in step (2) is 1300-1600°C.

[0013] Preferably, during the vacuum thermite reaction in step (2), argon is blown on both sides, and three argon tubes are arranged in parallel on each side.

[0014] Preferably, the openings of the three argon gas pipes are located on the same straight line, and the angle between the straight line and the horizontal direction is 30-60°.

[0015] Preferably, from top to bottom, the ratio of the distances between the orifices of the three argon gas tubes is (1.8-2.2):(2.8-3.2).

[0016] Preferably, from top to bottom, the flow rates of the three argon gas pipes are (0.5-2) L / s, (2-4) L / s and (5-9) L / s respectively.

[0017] Preferably, the vacuum thermite reaction in step (2) is carried out in a vacuum thermite furnace, and ignition is started when the vacuum degree of the vacuum thermite furnace is less than 50 Pa.

[0018] Preferably, the time of the vacuum thermite reaction in step (2) is 10 to 20 minutes.

[0019] The present invention also provides an aviation-grade vanadium-aluminum alloy prepared by the preparation method described in the above technical solution.

[0020] The present invention provides a method for preparing aviation-grade vanadium-aluminum alloy, comprising the following steps: mixing vanadium pentoxide and aluminum particles and then pressing to obtain a mixture tablet; subjecting the mixture tablet to a vacuum aluminothermic reaction under side-blowing argon gas, and then cooling to obtain a vanadium-aluminum alloy ingot with an upper layer of an aluminum oxide layer; the angle between the argon gas pipe of the side-blowing argon gas and the horizontal direction is 30 to 60 degrees; removing the aluminum oxide layer on the upper layer of the vanadium-aluminum alloy ingot to obtain an aviation-grade vanadium-aluminum alloy. The present invention uses side-blowing argon gas during vacuum aluminothermic reaction, and the angle of the side-blowing argon gas can destroy the high vacuum area, so that the aluminum oxide slag inside the vanadium-aluminum alloy is completely separated from the vanadium-aluminum alloy ingot, and a floating aluminum oxide layer is formed on the surface of the vanadium-aluminum alloy ingot, and at the same time, it is in an argon gas protective atmosphere, ensuring that after the high vacuum area is destroyed, the nitrogen element in the vanadium-aluminum alloy ingot will not increase, thereby reducing the aluminum oxide inclusion content and nitrogen content of the vanadium-aluminum alloy, and obtaining a high-purity vanadium-aluminum alloy. Experimental results show that the vanadium-aluminum alloy prepared by the present invention has no aluminum oxide inclusions, and the nitrogen content is ≤0.006wt%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the preparation of aviation-grade vanadium aluminum alloy according to the present invention.

[0022] In the figure, 1, 2 and 3 are argon tubes, 4 is a mixed material sheet, 5 is corundum powder, 6 is alumina inclusion, 7 is a floating alumina layer, 8 is an argon pore, 9 is alumina, 10 is a vanadium aluminum alloy ingot, and 11 is a copper crucible;

[0023] Figure 2 Schematic diagram of conventional preparation of vanadium aluminum alloy;

[0024] Figure 3 This is the metallographic diagram of the aviation-grade vanadium aluminum alloy prepared in Example 1;

[0025] Figure 4 This is the metallographic diagram of the aviation-grade vanadium aluminum alloy prepared in Example 2;

[0026] Figure 5 This is the metallographic phase diagram of the aviation-grade vanadium aluminum alloy prepared in Example 3. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing aviation-grade vanadium-aluminum alloy, comprising the following steps:

[0028] (1) mixing vanadium pentoxide and aluminum particles and pressing the mixture to obtain a mixture tablet;

[0029] (2) subjecting the mixed sheet obtained in step (1) to a vacuum aluminum thermite reaction under side-blown argon, and then cooling to obtain a vanadium aluminum alloy ingot with an upper layer of an aluminum oxide layer; the angle between the argon pipe of the side-blown argon and the horizontal direction is 30 to 60 degrees;

[0030] (3) removing the aluminum oxide layer on the upper layer of the vanadium aluminum alloy ingot obtained in step (2) to obtain aviation-grade vanadium aluminum alloy.

[0031] The present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0032] The present invention mixes vanadium pentoxide and aluminum particles and then compresses them to obtain a mixture tablet.

[0033] In the present invention, the purity of the vanadium pentoxide is preferably ≥99.5wt%; the particle size of the aluminum particles is preferably 0.8-1.5mm; the purity of the aluminum particles is preferably ≥99.8wt%; the mass ratio of the vanadium pentoxide to the aluminum particles is preferably (8-14):(9-10). The present invention limits the mass ratio of vanadium pentoxide to aluminum particles within the above range to ensure that the vanadium content in the vanadium-aluminum alloy is between 50 and 78wt%.

[0034] As an embodiment, the mass ratio of the vanadium pentoxide to the aluminum particles may be (9-13): (9.2-9.8), or may be (10-12): (9.4-9.6).

[0035] The present invention has no special limitation on the operation of mixing the vanadium pentoxide and aluminum particles, and the technical scheme for preparing the mixed material well known to those skilled in the art can be adopted.

[0036] In the present invention, the pressing is preferably performed by a hydraulic press. The present invention has no particular limitation on the type of the hydraulic press, and any equipment well known to those skilled in the art can be used.

[0037] In the present invention, the pressing pressure is preferably 0.5-2t; the pressing time is preferably 10-50s. As an embodiment, the pressing pressure can be 0.8-1.8t, or 0.9-1.5t; the pressing time can be 12-30s, or 15-25s.

[0038] In the present invention, the thickness of the mixture tablet is preferably 0.5 to 1.5 cm; the diameter of the mixture tablet is preferably 1 to 10 cm, more preferably 3 to 10 cm. In the present invention, in order to ensure the smooth progress of the reaction, when preparing high-grade vanadium aluminum alloy, a large-sized mixture tablet is used for thermite reaction, which can reduce the reaction rate, reduce the spraying furnace, and improve the alloy yield.

[0039] After obtaining the mixture sheet, the present invention conducts a vacuum aluminothermic reaction on the mixture sheet under side-blown argon, and then cools it to obtain a vanadium-aluminum alloy ingot with an aluminum oxide layer on the upper layer.

[0040] In the present invention, the angle between the argon pipe of the side-blowing argon and the horizontal direction is 30-60°, preferably 35-55°, more preferably 40-45°. The present invention limits the angle of the side-blowing argon to the above range to reduce the blowing resistance.

[0041] In the present invention, the temperature of the side-blown argon gas is preferably 1300-1600° C. As an embodiment, the temperature of the side-blown argon gas may be 1350-1560° C., or 1450-1500° C. The present invention can ensure that the alloy will not solidify with the slag due to the excessively low gas temperature by limiting the temperature of the side-blown argon gas within the above range.

[0042] like Figure 1 As shown, in one embodiment of the present invention, argon is blown on both sides during the vacuum aluminum thermite reaction; three argon pipes are arranged in parallel on each side; the pipe openings of the three argon pipes are located on the same straight line. The present invention adopts argon blowing on both sides to further reduce the aluminum oxide inclusion content and nitrogen content of the vanadium aluminum alloy; the three-stage argon blowing is conducive to reducing the pressure when the lower pores are formed.

[0043] In the present invention, the angle between the straight line and the horizontal direction is preferably 30 to 60°, more preferably 40 to 50°.

[0044] In the present invention, the mixture sheet is preferably subjected to vacuum thermite reaction in a crucible; the material of the crucible is preferably copper.

[0045] like Figure 1 As shown, in one embodiment of the present invention, two partitions are arranged in the crucible; the height of the partition is lower than the height of the crucible; corundum powder is arranged between the partition and the side wall of the crucible; the corundum powder is arranged in a slope. In the present invention, the mixture tablets are placed between the partitions and on the slope.

[0046] In the present invention, the particle size of the corundum powder is preferably 0.1 to 1 mm. The present invention uses corundum powder to cover the argon tube to ensure that the argon tube does not melt during the thermite reaction; limiting the particle size of the corundum powder within the above range can prevent the particle size from being too large, so that the alloy reaction liquid penetrates into the corundum powder to melt the argon tube, and can also prevent the particle size from being too small to block the argon pipeline.

[0047] In the present invention, the slope of the slope is preferably 30-60°; the angle between the orifice of the argon pipe and the slope is preferably 60-90°. The present invention specifies that the angle between the orifice of the argon pipe and the slope within the above range can ensure that the reaction process can smoothly break the high vacuum area.

[0048] like Figure 1 In one embodiment of the present invention, from top to bottom, the tube opening of the lowest argon tube of the three argon tubes is arranged at the upper edge of the partition.

[0049] In the present invention, from top to bottom, the ratio of the distance between the tube openings of the three argon tubes is preferably (1.8-2.2): (2.8-3.2). As an embodiment, the ratio of the distance between the tube openings of the three argon tubes can be (1.9-2.1): (2.9-3.1), or can be 2:3. The present invention limits the distance between the tube openings of the three argon tubes within the above range to ensure that the lowest argon tube can successfully destroy the high vacuum local area.

[0050] In the present invention, the ratio of the distance between the topmost argon pipe opening and the crucible in the slope direction to the distance between the middle argon pipe opening and the topmost argon pipe opening in the slope direction is preferably (0.8-1.2):(1.8-2.2). As an embodiment, the ratio of the distance between the topmost argon pipe opening and the crucible in the slope direction to the distance between the middle argon pipe opening and the topmost argon pipe opening in the slope direction can be (0.9-1.1):(1.9-2.1), and can also be 1:2.

[0051] In the present invention, the vacuum thermite reaction is preferably carried out in a vacuum thermite furnace. The present invention has no particular limitation on the type of the vacuum thermite furnace, and any equipment well known to those skilled in the art can be used.

[0052] In the present invention, ignition is preferably started when the vacuum degree of the vacuum aluminum thermite furnace is less than 50 Pa. In the present invention, ignition is started when the vacuum degree is less than 50 Pa, which can prevent the air in the furnace from entering the alloy at the initial stage of the reaction and increasing the nitrogen content in the alloy.

[0053] In the present invention, from top to bottom, the topmost argon tube of the three argon tubes is preferably opened 20 to 40 seconds after ignition; the middle argon tube of the three argon tubes is preferably opened 80 to 120 seconds after ignition; the bottommost argon tube of the three argon tubes is preferably opened 250 to 350 seconds after ignition. The present invention adopts a step-by-step argon delivery method to ensure that the material in the upper part of the argon tube is fully ventilated after reaction, thereby preventing the raw material from splashing; since the reaction is carried out from top to bottom, it is convenient to separate the alloy and slag at each stage of the vacuum aluminothermic reaction.

[0054] As an implementation mode, from top to bottom, the topmost argon tube of the three argon tubes can be opened 25 to 30 seconds after ignition; the middle argon tube of the three argon tubes can be opened 88 to 102 seconds after ignition, and can also be opened after 90 seconds; the bottommost argon tube of the three argon tubes can be opened 255 to 300 seconds after ignition, and can also be opened after 260 to 262 seconds.

[0055] In the present invention, from top to bottom, the flow rates of the three argon tubes are preferably (0.5-2) L / s, (2-4) L / s and (5-9) L / s. As an embodiment, the flow rates of the three argon tubes may be (0.6-1.5) L / s, (2.2-3.5) L / s and (5.6-8) L / s, or (0.7-0.8) L / s, (2.4-3.0) L / s and (6.0-7.0) L / s. The present invention limits the flow rates of the three argon tubes in the above ranges in turn to ensure that the lowest argon tube successfully destroys the high vacuum local area.

[0056] In the present invention, the time of the vacuum thermite reaction is preferably 10 to 20 minutes. As an embodiment, the time of the vacuum thermite reaction can be 12 to 18 minutes, or 12 to 15 minutes. The present invention has no special limitation on the temperature of the vacuum thermite reaction, and a temperature familiar to those skilled in the art can be used. In the present invention, the time of the vacuum thermite reaction is the reaction time after the vacuum thermite reaction is ignited.

[0057] In the present invention, the cooling is preferably natural cooling; the time of the natural cooling is preferably ≥ 4h.

[0058] After obtaining a vanadium-aluminum alloy ingot with an aluminum oxide layer on the upper layer, the present invention removes the aluminum oxide layer on the upper layer of the vanadium-aluminum alloy ingot to obtain aviation-grade vanadium-aluminum alloy.

[0059] In the present invention, sandblasting is preferably used to remove the alumina layer on the upper layer of the vanadium aluminum alloy ingot; the sandblasting is preferably performed using aluminum particles; the particle size of the aluminum particles is preferably 1 to 3 mm; and the pressure of the sandblasting is preferably 15 to 30 MPa. In the present invention, since the higher the vanadium grade in the alloy, the higher the melting point of the vanadium aluminum alloy, the closer the alloy and the floating alumina layer will be, and the sandblasting pressure needs to be adjusted. Using aluminum particles as sandblasting materials can reduce the problem of increased iron and silicon in the post-processing process of the vanadium aluminum alloy caused by conventional sandblasting materials. Using aluminum particles of the above particle size can fully remove impurities from the irregular surface of the alloy ingot.

[0060] In the present invention, the sandblasting is preferably performed by a high-pressure sandblasting machine. The present invention has no particular limitation on the model of the high-pressure sandblasting machine, and any equipment well known to those skilled in the art can be used.

[0061] After removing the aluminum oxide layer on the upper layer of the vanadium aluminum alloy ingot, the present invention preferably sequentially performs shot blasting, finishing and removal of the surface layer and loose materials on the product obtained after removing the aluminum oxide layer to obtain aviation-grade vanadium aluminum alloy.

[0062] The present invention has no special limitation on the operations of shot blasting, finishing and removing the surface layer and loose materials, and operations well known to those skilled in the art may be adopted.

[0063] The present invention adopts side blowing of argon during vacuum aluminum thermite reaction. The high vacuum area can be destroyed by the angle of the side blowing of argon, so that the aluminum oxide slag inside the vanadium aluminum alloy is completely separated from the outside of the vanadium aluminum alloy ingot, and a floating aluminum oxide layer is formed on the surface of the vanadium aluminum alloy ingot. At the same time, it is in an argon protective atmosphere, ensuring that after the high vacuum area is destroyed, the nitrogen element in the vanadium aluminum alloy ingot will not increase, thereby reducing the aluminum oxide inclusion content and nitrogen content of the vanadium aluminum alloy, and obtaining a high-purity vanadium aluminum alloy.

[0064] The present invention prepares a high-purity, low-nitrogen vanadium aluminum alloy through a vacuum aluminum heat-blowing method, providing a new possibility for the development of aviation-grade vanadium aluminum alloys for cutting-edge equipment.

[0065] Existing conventional aluminothermic method (such as Figure 2 ), the reaction proceeds from top to bottom, and the heat generated by the reaction above continuously provides activation energy for the reaction of the materials below to ensure that the oxides are completely reduced. This process is affected by density, and the aluminum oxide moves upward and the alloy moves downward. Since the melting point of aluminum oxide is 2050°C, which is much higher than the melting point of vanadium-aluminum alloy, the aluminum oxide exposed to the air solidifies first. At this time, the internal aluminum thermal reaction has not ended, resulting in the inability to separate the air and furnace gas inside the alloy from the outside of the system, and forming a high-pressure area between the aluminum oxide and the vanadium-aluminum alloy ingot. As a result, when the alloy is in a molten state, the surface tension and static pressure of the upper surface in contact with the high-pressure area are too large, affecting the internal aluminum oxide slag and making it impossible to separate it from the alloy ingot. In order to accelerate the aluminum oxide slag inclusion inside the alloy ingot, the high vacuum area needs to be destroyed. However, after the upper aluminum oxide layer of the conventional aluminum thermal method is destroyed, nitrogen will be introduced into the alloy. However, in the present invention, in a vacuum aluminum thermal furnace (such as Figure 1 ), by destroying the alumina layer and the high vacuum area through high-pressure argon gas, the alumina slag inside the vanadium-aluminum alloy can be completely separated from the alloy ingot, and a floating alumina layer is formed on the surface of the alloy ingot. At the same time, because the furnace is in an argon protective atmosphere, it is ensured that after the high vacuum area is destroyed, the nitrogen element in the alloy ingot will not increase.

[0066] The present invention also provides an aviation-grade vanadium-aluminum alloy prepared by the preparation method described in the above technical solution.

[0067] In the present invention, the aviation-grade vanadium aluminum alloy preferably includes the following chemical components, by mass percentage: 50-78% vanadium, ≤0.08% iron, ≤0.08% silicon, ≤0.015% oxygen, ≤0.006% nitrogen and the balance aluminum.

[0068] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] Example 1

[0070] The preparation method of aviation grade vanadium aluminum alloy is as follows:

[0071] (1) 103.5 kg of vanadium pentoxide with a purity of ≥99.5 wt% and 93 kg of aluminum particles with a particle size of 0.8 to 1.5 mm and a purity of ≥99.8 wt% were fully mixed in a mixer, put into a mold and pressed on a 0.8 t hydraulic press for 12 seconds to obtain a mixture sheet with a thickness of 0.6 cm and a diameter of 3 cm;

[0072] (2) transferring the mixture obtained in step (1) into a copper crucible and then performing a vacuum aluminothermic reaction in a vacuum aluminothermic furnace with argon gas blowing on both sides for 12 minutes, and cooling naturally for 5 hours to obtain 97.8 kg of vanadium aluminum alloy ingots with an upper aluminum oxide layer;

[0073] Among them, the angle between the argon pipe of the side-blown argon and the horizontal direction is 40°; the temperature of the side-blown argon is 1450°C; three argon pipes are arranged in parallel on each side; the pipe openings of the three argon pipes are located on the same straight line, and the angle between the straight line and the horizontal direction is 50°; two partitions are arranged in the crucible; the height of the partition is lower than the height of the crucible; corundum powder is arranged between the partition and the side wall of the crucible; the corundum powder is arranged in a slope, and the particle size is 0.4-0.8mm; the slope of the slope is 50°; the angle between the pipe opening of the argon pipe and the slope is 90°; from top to bottom, the pipe opening of the lowest argon pipe of the three argon pipes is arranged Placed at the upper edge of the partition; the ratio of the distance between the top argon tube opening and the crucible in the slope direction to the distance between the middle argon tube and the top argon tube opening in the slope direction is 1:2; from top to bottom, the ratio of the distance between the tube openings of the three argon tubes is 2:3 (i.e. ab:bc:cd is 1:2:3); ignite when the vacuum degree in the vacuum aluminum thermite furnace is evacuated to 20Pa, open the top argon tube 20s after ignition, the flow rate is 0.7L / s, open the middle argon tube 88s after ignition, the flow rate is 2.2L / s, and open the bottom argon tube 255s after ignition, the flow rate is 5.6L / s;

[0074] (3) A high-pressure sandblasting machine was used to remove the upper aluminum oxide layer at 18 MPa, and then shot blasting, finishing, and removal of the surface layer and loose materials were performed in sequence to obtain 97 kg of aviation-grade vanadium aluminum alloy; wherein aluminum particles with a particle size of 1 to 3 mm were used for sandblasting.

[0075] The metallographic image of the aviation-grade vanadium aluminum alloy prepared in Example 1 is as follows: Figure 3 The results of multi-point sampling and testing of the aviation-grade vanadium aluminum alloy prepared in Example 1 are shown in Table 1.

[0076] Table 1 Sampling results analysis of aviation grade vanadium aluminum alloy prepared in Example 1

[0077]

[0078] from Figure 3 It can be seen that there is no aluminum oxide inclusion in the field of view, and the alloy purity is relatively high; as can be seen from Table 1, the oxygen and nitrogen content in the vanadium aluminum alloy is extremely low, and the uniformity of each element is relatively high, which meets the standards for intermediate alloys for cutting-edge titanium alloys.

[0079] Example 2

[0080] The preparation method of aviation grade vanadium aluminum alloy is as follows:

[0081] (1) 116 kg of vanadium pentoxide with a purity of ≥99.5 wt% and 93 kg of aluminum particles with a particle size of 0.8 to 1.5 mm and a purity of ≥99.8 wt% were fully mixed in a mixer, put into a mold and pressed on a 0.9 t hydraulic press for 18 seconds to obtain a mixture sheet with a thickness of 0.8 cm and a diameter of 6 cm;

[0082] (2) transferring the mixture obtained in step (1) into a copper crucible and then performing a vacuum aluminothermic reaction in a vacuum aluminothermic furnace with argon gas blowing on both sides for 12 minutes, and cooling naturally for 5 hours to obtain 98 kg of vanadium aluminum alloy ingots with an upper aluminum oxide layer;

[0083] Among them, the angle between the argon pipe of the side-blown argon and the horizontal direction is 45°; the temperature of the side-blown argon is 1560°C; three argon pipes are arranged in parallel on each side; the pipe openings of the three argon pipes are located on the same straight line, and the angle between the straight line and the horizontal direction is 50°; two partitions are arranged in the crucible; the height of the partition is lower than the height of the crucible; corundum powder is arranged between the partition and the side wall of the crucible; the corundum powder is arranged in a slope, and the particle size is 0.4-0.8mm; the slope of the slope is 50°; the angle between the pipe opening of the argon pipe and the slope is 85°; from top to bottom, the pipe opening of the lowest argon pipe of the three argon pipes is arranged Placed at the upper edge of the partition; the ratio of the distance between the top argon tube opening and the crucible in the slope direction to the distance between the middle argon tube and the top argon tube opening in the slope direction is 1:2; from top to bottom, the ratio of the distance between the tube openings of the three argon tubes is 2:3 (i.e. ab:bc:cd is 1:2:3); ignite when the vacuum degree in the vacuum aluminum thermite furnace is evacuated to 20Pa, open the top argon tube 25s after ignition, the flow rate is 0.8L / s, open the middle argon tube 90s after ignition, the flow rate is 2.4L / s, and open the bottom argon tube 260s after ignition, the flow rate is 6.2L / s;

[0084] (3) A high-pressure sandblasting machine was used to remove the upper aluminum oxide layer at 18.5 MPa, and then shot blasting, finishing, and removal of the surface layer and loose materials were performed in sequence to obtain 96.5 kg of aviation-grade vanadium aluminum alloy; wherein aluminum particles with a particle size of 1 to 3 mm were used for sandblasting.

[0085] The metallographic image of the aviation-grade vanadium aluminum alloy prepared in Example 2 is as follows: Figure 4 Table 2 shows the results of multi-point sampling and testing of the aviation-grade vanadium aluminum alloy prepared in Example 2.

[0086] Table 2 Analysis of sampling results of aviation-grade vanadium aluminum alloy prepared in Example 2

[0087]

[0088] from Figure 4 It can be seen that there is no aluminum oxide inclusion in the field of view, and the alloy purity is relatively high; from Table 2, it can be seen that the oxygen and nitrogen content in the vanadium aluminum alloy is extremely low, and the uniformity of each element is relatively high.

[0089] Example 3

[0090] The preparation method of aviation grade vanadium aluminum alloy is as follows:

[0091] (1) 133.8 kg of vanadium pentoxide with a purity of ≥99.5 wt% and 91.2 kg of aluminum particles with a particle size of 0.8 to 1.5 mm and a purity of ≥99.8 wt% were fully mixed in a mixer, put into a mold and pressed on a 1.8 t hydraulic press for 25 seconds to obtain a mixture sheet with a thickness of 1.2 cm and a diameter of 9 cm;

[0092] (2) transferring the mixture sheet obtained in step (1) into a copper crucible, and then performing a vacuum aluminothermic reaction in a vacuum aluminothermic furnace with argon gas blown on both sides for 12 minutes, and naturally cooling the temperature for 5 hours to obtain 96 kg of vanadium aluminum alloy ingots with an upper aluminum oxide layer;

[0093] Among them, the angle between the argon pipe of the side-blown argon and the horizontal direction is 50°; the temperature of the side-blown argon is 1560°C; three argon pipes are arranged in parallel on each side; the pipe openings of the three argon pipes are located on the same straight line, and the angle between the straight line and the horizontal direction is 50°; two partitions are arranged in the crucible; the height of the partition is lower than the height of the crucible; corundum powder is arranged between the partition and the side wall of the crucible; the corundum powder is arranged in a slope, and the particle size is 0.4-0.8mm; the slope of the slope is 50°; the angle between the pipe opening of the argon pipe and the slope is 80°; from top to bottom, the pipe opening of the lowest argon pipe of the three argon pipes is arranged Placed at the upper edge of the partition; the ratio of the distance between the top argon tube opening and the crucible in the slope direction to the distance between the middle argon tube and the top argon tube opening in the slope direction is 1:2; from top to bottom, the ratio of the distance between the tube openings of the three argon tubes is 2:3 (i.e. ab:bc:cd is 1:2:3); when the vacuum degree in the vacuum aluminum thermite furnace is evacuated to 20Pa, ignite, open the top argon tube 30s after ignition, the flow rate is 0.8L / s, open the middle argon tube 102s after ignition, the flow rate is 2.2L / s, and open the bottom argon tube 266s after ignition, the flow rate is 7L / s;

[0094] (3) A high-pressure sandblasting machine was used to remove the upper aluminum oxide layer at 25 MPa, and then shot blasting, finishing, and removal of the surface layer and loose materials were performed in sequence to obtain 95 kg of aviation-grade vanadium aluminum alloy; wherein aluminum particles with a particle size of 1 to 3 mm were used for sandblasting.

[0095] The metallographic image of the aviation-grade vanadium aluminum alloy prepared in Example 3 is as follows: Figure 5 Table 3 shows the results of multi-point sampling and testing of the aviation-grade vanadium aluminum alloy prepared in Example 3.

[0096] Table 3 Analysis of sampling results of aviation-grade vanadium aluminum alloy prepared in Example 3

[0097]

[0098]

[0099] from Figure 5 It can be seen that there is no aluminum oxide inclusion in the field of view, and the alloy purity is relatively high; from Table 3, it can be seen that the oxygen and nitrogen content in the vanadium aluminum alloy is extremely low, and the uniformity of each element is relatively high.

[0100] It can be seen from the above examples that the preparation method provided by the present invention can produce a high-purity, low-nitrogen aviation-grade vanadium-aluminum alloy.

[0101] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing aviation-grade vanadium aluminum alloy, comprising the following steps: (1) mixing vanadium pentoxide and aluminum particles and pressing the mixture to obtain a mixture tablet; (2) subjecting the mixed sheet obtained in step (1) to a vacuum aluminum thermite reaction under side-blown argon, and then cooling to obtain a vanadium aluminum alloy ingot with an upper layer of an aluminum oxide layer; the angle between the argon pipe of the side-blown argon and the horizontal direction is 30 to 60 degrees; (3) removing the aluminum oxide layer on the upper layer of the vanadium aluminum alloy ingot obtained in step (2) to obtain aviation-grade vanadium aluminum alloy.

2. The preparation method according to claim 1, characterized in that: In the step (1), the mass ratio of vanadium pentoxide to aluminum particles is (8-14):(9-10).

3. The preparation method according to claim 1, characterized in that: The temperature of the side-blown argon gas in step (2) is 1300-1600°C.

4. The preparation method according to claim 1, characterized in that: During the vacuum thermite reaction in step (2), argon is blown on both sides, and three argon tubes are arranged in parallel on each side.

5. The preparation method according to claim 4, characterized in that: The openings of the three argon gas pipes are located on the same straight line, and the angle between the straight line and the horizontal direction is 30-60°.

6. The preparation method according to claim 5, characterized in that: From top to bottom, the ratio of the distances between the tube openings of the three argon tubes is (1.8-2.2):(2.8-3.2).

7. The preparation method according to claim 5, characterized in that: From top to bottom, the flow rates of the three argon gas tubes are (0.5-2) L / s, (2-4) L / s and (5-9) L / s, respectively.

8. The preparation method according to claim 1, characterized in that: The vacuum thermite reaction in step (2) is carried out in a vacuum thermite furnace, and ignition is started when the vacuum degree of the vacuum thermite furnace is less than 50Pa.

9. The preparation method according to claim 1, characterized in that: The time of the vacuum thermite reaction in step (2) is 10 to 20 minutes.

10. Aviation-grade vanadium aluminum alloy prepared by the preparation method according to any one of claims 1 to 9.

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