A solidification device and method for preparing high-temperature alloys by combining bidirectional ultrasonic vibration and directional solidification

Abstract

A solidification device and method for preparing high-temperature alloys by combining bidirectional ultrasonic vibration with directional solidification, which relates to the field of metal precision casting. The present invention is intended to solve the problem that the high-temperature alloys prepared by existing directional solidification equipment that pulls in a single direction have large anisotropy, resulting in poor room-temperature fracture toughness of the alloy's mechanical properties. The induction heating system of the present invention is placed in the center of the furnace body. The alloy billet is heated and melted by a seven-turn electromagnetic induction coil. Two sets of ultrasonic equipment are installed on both sides in a symmetrical manner with the lower pulling rod as the center. During the downward pulling of the upper and lower pulling rods, the bidirectional ultrasonic equipment indirectly introduces ultrasonic waves into the alloy melt through the crucible. The alloy microstructure is regulated over a large range to improve the alloy's mechanical properties and improve the strong anisotropy of the mechanical properties of the alloys prepared by ordinary directional solidification equipment. The present invention is used for the preparation of high-temperature alloys.

Description

Technical Field

[0001] The present invention relates to a solidification device and method for preparing a high-temperature alloy, and in particular to a solidification device and method for preparing a high-temperature alloy by combining bidirectional ultrasonic vibration with directional solidification, belonging to the field of metal precision casting. Background Art

[0002] As science and technology advance towards higher-end and more specialized applications, engine materials are also developing rapidly. Examples include niobium-silicon alloys, titanium alloys, nickel alloys, and other high-temperature alloys. Take niobium-silicon superalloys, for example. These alloys consist of a niobium-based solid solution phase (Nbss) and refractory intermetallic compounds (Nb3Si and Nb5Si3). The temperature resistance of these refractory intermetallic silicides lies between that of high-temperature alloys and ceramics. Therefore, Nb-Si alloys hold great potential as a next-generation ultra-high-temperature structural material.

[0003] Refractory intermetallic silicides have high strength, but their room temperature fracture toughness is very low. For example, the fracture toughness of Nb5Si3 is only 3MPa·m 1 / 2 Although the room-temperature fracture toughness of niobium-based solid solution phases is very good, the room-temperature fracture toughness of niobium-silicon alloys still cannot meet the requirements of room-temperature assembly, limiting their application in aviation, aerospace and other fields. Therefore, improving the room-temperature fracture toughness of niobium-silicon alloys has become a key issue.

[0004] Currently, there are many approaches to improving the room-temperature fracture toughness of niobium-silicon alloys, primarily through alloying and modifying the preparation process. Essentially, these approaches enhance the toughness of Nb-Si alloys by manipulating the phase structure, composition, and microstructure. Directional solidification, a process that improves the room-temperature fracture toughness of Nb-Si alloys, forms a phase structure oriented in a single direction. However, the alloy structure formed by directional solidification suffers from a significant disadvantage: the mechanical properties of castings produced by directional solidification differ significantly between those perpendicular to the direction of pull. This discrepancy stems from the principle of conventional directional solidification equipment. Traditional directional solidification equipment uses a pull rod to pull the molten metal in the same direction while solidifying. As the liquid phase solidifies, the alloy structure develops numerous elongated grains oriented parallel to the pull direction. These elongated grains exhibit varying effects on loads in different directions. For example, toughness represents the ability of a crack to propagate within the metal. Higher toughness indicates slower crack propagation, while lower toughness indicates faster crack propagation. If a crack source propagates perpendicular to the orientation of the elongated grains, the crack will penetrate many of these grain boundaries during propagation, significantly increasing the resistance to crack propagation and making crack propagation more difficult. Therefore, the toughness of an alloy increases significantly in directions perpendicular to the elongated grains. However, if a crack source propagates parallel to the elongated grains, the resistance to crack propagation decreases significantly, making crack propagation easier. Consequently, the toughness of an alloy decreases in directions parallel to the elongated grains.

[0005] The high-temperature alloy structure produced by the existing directional solidification equipment that pulls in a single direction contains a large number of long strip-shaped grains parallel to the pulling direction. When this structure is subjected to loads in different directions, it will show different fracture mechanisms. This causes the mechanical properties of the alloy to vary greatly in different directions, which in turn leads to the problem of poor performance of the prepared high-temperature alloy. When the mechanical properties of the alloy produce strong anisotropy due to the directional structure, this property will greatly limit the application of the prepared alloy in the field of structural materials, especially limiting its application in structures with complex stress modes and large stress requirements. For example, aircraft fuselage structural parts, landing gear, etc. Although subsequent heat treatment may change this shortcoming, the heat treatment cost is high for some high-temperature materials, and it takes a long time and is inefficient.

[0006] In summary, the high-temperature alloys produced by existing directional solidification equipment that pulls in a single direction have large mechanical anisotropy, resulting in large differences in the mechanical properties of the alloy in different directions, which in turn leads to the problem of poor performance of the produced high-temperature alloys. Summary of the Invention

[0007] The present invention aims to address the problem of high-temperature alloys produced by existing directional solidification equipment using a single-direction pull, resulting in significant anisotropy and poor room-temperature fracture toughness. Furthermore, a solidification device and method for producing high-temperature alloys is provided, combining bidirectional ultrasonic vibration with directional solidification.

[0008] The technical solution of the present invention is: a solidification equipment for preparing high-temperature alloys by combining bidirectional ultrasonic vibration with directional solidification, which includes a furnace body, a furnace door, an upper pull rod, a lower pull rod, an upper elevator, a lower elevator, a pressure gauge, an argon valve, an air valve, a heating system, a stand assembly, a cooling system, a left transducer, a right transducer, a left amplitude rod, a right amplitude rod, a left tool head, a right working head and a main control cabinet; the pressure gauge is installed on the left end face of the outer side of the furnace body, the stand assembly is installed at the lower end of the furnace body, and the argon valve and the air valve are installed at the lower right end of the outer side of the furnace body; the cooling system is installed in the furnace body, one end of the lower pull rod is sealed and slides through the cooling system and then extends to the upper part of the furnace body, and the other end of the lower pull rod is connected to the stand assembly The upper pull-out rod is connected to the lower elevator, one end of the upper pull-out rod is sealed and slidably installed on the furnace body and extends to the lower part of the furnace body, and the other end of the upper pull-out rod is connected to the upper elevator; the heating system is installed in the middle of the furnace body and is located at the upper end of the cooling system, and the heating system is cooled by water; the left amplitude rod and the right amplitude rod are symmetrically arranged with the lower pull-out rod as the center, and the right end of the left amplitude rod contacts the lower pull-out rod through the left tool head, the left end of the left amplitude rod is located outside the furnace body and connected to the left transducer, the left end of the right amplitude rod contacts the lower pull-out rod through the right working head, and the right end of the right amplitude rod is located outside the furnace body and connected to the right transducer; the main control cabinet is electrically connected to the upper elevator, lower elevator, heating system, left transducer and right transducer respectively.

[0009] Furthermore, it also includes a furnace door, which is connected to the furnace body through a screw-fastening bolt locking device, the top of the furnace body is equipped with a top observation window through a top observation window pressure cover, and the front of the furnace body is equipped with a front observation window through a front observation window pressure cover.

[0010] Furthermore, the heating system includes a seven-turn square-section electromagnetic induction coil, a heat-resistant protective cover, a cylindrical heating element, a crucible and an alloy billet; the alloy billet is installed in the crucible, the cylindrical heating element is mounted on the outside of the crucible, the heat-resistant protective cover is mounted on the outside of the cylindrical heating element, and the seven-turn square-section electromagnetic induction coil is mounted on the outside of the heat-resistant protective cover.

[0011] Furthermore, the distance between the seven-turn square cross-section electromagnetic induction coil and the heat-resistant protective sleeve is 15 mm, the distance between the heat-resistant protective sleeve and the cylindrical heating element is 10 mm, and the distance between the cylindrical heating element and the crucible is 8 mm.

[0012] Furthermore, the seven-turn square cross-section electromagnetic induction coil is made of copper and is cooled by water.

[0013] Furthermore, the cooling system includes a cooling chamber, a cooling cover and Ga-In liquid. The cooling cover is installed on the cooling chamber, and the cooling chamber is filled with Ga-In liquid.

[0014] Furthermore, the cooling system also includes a water inlet pipe, a water outlet pipe, a water inlet interface, a water outlet interface, a water inlet pipe plug-in plate and a water outlet pipe plug-in plate; one end of the water inlet pipe and the water outlet pipe are respectively connected to the induction coil through the water inlet interface and the water outlet interface, and the other end of the water inlet pipe and the water outlet pipe are respectively connected to the water inlet pipe plug-in plate and the water outlet pipe plug-in plate.

[0015] Preferably, the water outlet pipe plug-in plate and the water inlet pipe plug-in plate are respectively installed on the inner side wall of the furnace body.

[0016] The present invention also provides a method for preparing a high-temperature alloy by using a solidification device that combines bidirectional ultrasonic vibration with directional solidification to prepare a high-temperature alloy, which comprises the following steps:

[0017] Step 1: Adjust the position of the lower pull rod;

[0018] Adjust the upper end surface of the lower pull rod to align with the upper plane of the cooling chamber through the main control cabinet;

[0019] Step 2: Determine the location of the crucible;

[0020] Step 21: Cut an alloy billet from the alloy base material. The alloy billet is a cylindrical alloy raw material and is placed in a crucible. The crucible consists of a crucible body and a crucible cover. After the alloy billet is placed in the crucible body, the crucible cover is sealed.

[0021] Step 22: Place the crucible just above the upper end of the lower pull rod in the furnace body; at this time, adjust the main control cabinet, lower the upper pull rod and press it against the upper end of the crucible, while ensuring that the crucible does not move out of its relative position during the simultaneous movement of the upper and lower pull rods;

[0022] Step 3: Debug the cooling system:

[0023] After adjusting the positions of the components, close the furnace door and tighten it with screw bolts to prevent air leakage. Turn on the cooling system and observe whether there is water seepage in the furnace through the top and front observation windows. If there is water seepage, stop the preparation and seal the furnace. If there is no water seepage, proceed to the next step:

[0024] Step 4: Evacuate the furnace and introduce argon gas into the furnace:

[0025] Use the vacuum pump to evacuate the furnace to -0.1MPa, and continue to evacuate the furnace using the molecular pump until the pressure inside the furnace reaches 0.001-0.8. Then, open the argon valve and introduce argon into the furnace as a protective gas. Observe the pressure gauge and introduce 0.08MPa of argon into the furnace.

[0026] Step 5: Check the top and front windows again to see if there is any water leakage inside the device, and make sure that the upper and lower pull rods are clamping the crucible tightly.

[0027] Step 6: Adjust the ultrasonic vibration power of the left and right transducers through the main control cabinet. The ultrasonic vibration power range is 1200-1800W;

[0028] Step 7: Set the heating time and heating power of the heating system through the main control cabinet. The adjustable range of heating time is 0-60min, the adjustable range of heating power is 25-60kW, the adjustable range of holding time is 0-48h, and the holding power is 2-12W;

[0029] Step 8: Set the pulling speed of the upper pull rod and the lower pull rod to 80-150 μm / s through the main control cabinet;

[0030] Step 9: After setting all parameters, start the induction heating of the heating system through the main control cabinet, then start the ultrasonic vibration of the left and right transducers, and finally start the pulling movement of the upper and lower pull rods;

[0031] Step 10: After the pulling movement is completed, turn off the heating system through the main control cabinet. If heat treatment is required, do not turn off the heating system; turn off the ultrasonic vibration of the left transducer and the right transducer, and adjust the positions of the upper pulling rod and the lower pulling rod to restore the crucible to the position of the lower pulling rod in step 1;

[0032] Step 11: Adjust the position of the upper pull rod through the main control cabinet, open the air valve, fill air into the interior of the furnace body, and unscrew the screw bolt locking device. After waiting for the temperature inside the furnace body to cool down, open the furnace door, take out the crucible, and take out the high-temperature alloy round rod prepared by combining the bidirectional ultrasonic vibration formed by the left and right transducers in the furnace body with directional solidification. The preparation of the high-temperature alloy is now completed.

[0033] Furthermore, the high-temperature alloy raw material is Nb-16Si-20Zr-2C high-temperature alloy.

[0034] Compared with the prior art, the present invention has the following effects:

[0035] 1. For Nb-Si alloys, alloys manufactured using traditional directional solidification have a large number of long Nbss phases and silicide phases parallel to the pulling direction in the microstructure. When a crack propagates in the microstructure, when the propagation direction is parallel to the pulling direction, the crack propagation is relatively easy. When the crack propagation direction is perpendicular to the pulling direction of the directional solidification equipment, the crack has to pass through many long phase boundaries of different phases, which will to a certain extent prevent the crack from propagating, thereby increasing the toughness of the alloy. However, due to the different crack propagation directions, the resulting toughness is also different. Therefore, the alloys prepared by traditional directional solidification equipment also show different toughness when loads in different directions are applied. The present invention applies bidirectional ultrasonic vibration (specifically, it is achieved by using the left transducer 13 and the right transducer 14) during the melting and solidification process of the directional solidification pulling out high-temperature alloy round rod, so that the directional solidification pulling out a sample with a slender columnar phase parallel to the solidification direction is broken by the cavitation effect of the ultrasonic wave, and many elongated silicide phases with different orientations are present in the microstructure. Because there are many elongated silicide phases with different orientations in the microstructure. The microstructure of the alloy becomes very uniform, unlike the directional solidification alloy structure, in which the elongated silicide phases are arranged in the same direction in the alloy microstructure. Therefore, when the alloy is subjected to loads in different directions, the crack propagation difference of the alloy is small, and the toughness is no longer anisotropic. This solves the problem of large differences in mechanical properties in various directions in traditional directional solidification alloys. At the same time, bidirectional ultrasound creates a standing wave field, causing elongated silicide phases with the same orientation to be arranged periodically within the alloy microstructure. This increases the degree of deflection during crack propagation, making crack propagation more difficult and increasing the alloy's toughness. Bidirectional ultrasound also produces a cavitation effect, which breaks down larger phases in the alloy microstructure, contributing to grain refinement and strengthening.

[0036] 2. The present invention installs the ultrasonic vibration device on both sides of the cooling chamber in a centrally symmetrical manner with the lower pull rod 4 as the center, introducing bidirectional vibrating ultrasonic waves into the alloy melt, that is, covering the entire area of ​​the melt, preventing the problem of incomplete action area of ​​unidirectional ultrasonic waves. The bidirectional ultrasonic waves also generate a standing wave field in the alloy melt, making it easy for long strip phases of different orientations to grow at the wave node position, and then present a periodic arrangement, further weakening the anisotropy of the mechanical properties of the alloy prepared by directional solidification, and improving the mechanical properties of the alloy.

[0037] 3. The present invention solves the problem of limited working temperature environment of the ultrasonic horn and tool head by directly extending the horn and the tool head into the cooling chamber cavity, indirectly introducing ultrasonic waves into the interior of the high-temperature alloy melt by acting on the surface of the crucible, and directly cooling the horn and the tool head with Ga-In liquid.

[0038] 4. The present invention utilizes a square-cross-section electromagnetic induction coil instead of a circular-cross-section one, increasing the heating area and thus improving the product's heating efficiency. Rectangular-cross-section coils make it easier to vary the emission flux, reducing energy consumption. They utilize space more efficiently and achieve a more uniform temperature across the heated surface, resulting in higher heating uniformity. For the same heating area, rectangular-cross-section induction coils offer the most material savings and a more uniform heat-transmitting layer.

[0039] 5. The device of the present invention can use a seven-turn square cross-section electromagnetic induction coil to heat treat the alloy round rod prepared by directional solidification with bidirectional ultrasonic vibration, and heat treat the alloy structure after heat treatment to further improve the mechanical properties of the alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of the device of the present invention;

[0041] Figure 2 It is a partial enlarged view of the heating system;

[0042] Figure 3 A top view of the device of the present invention;

[0043] Figure 4(a) shows the microstructure of a NbSi superalloy prepared using a conventional vacuum non-consumable arc melting device;

[0044] Figure 4(b) shows the microstructure of a NbSi superalloy prepared by combining ultrasonic vibration with directional solidification.

[0045] Figure 5 The room temperature fracture toughness of NbSi high temperature alloy prepared by ordinary vacuum non-consumable arc melting equipment and the room temperature fracture toughness of NbSi high temperature alloy prepared by a process combining ultrasonic vibration and directional solidification in the directions parallel to and perpendicular to the directional solidification direction. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is not limited to the specific implementation methods listed below, but also includes any reasonable combination of the specific implementation methods.

[0047] Specific implementation method 1: Combination Figures 1 to 3Describe this embodiment, this embodiment includes a furnace body 1, a furnace door 2, an upper pull rod 3, a lower pull rod 4, an upper elevator 5, a lower elevator 6, a pressure gauge 7, an argon valve 8, an air valve 9, a heating system 10, a stand assembly 11, a cooling system, a left transducer 13, a right transducer 14, a left amplitude rod 15, a right amplitude rod 16, a left tool head 17, a right working head 18 and a main control cabinet 19; the pressure gauge 7 is installed on the outer left end surface of the furnace body 1, the stand assembly 11 is installed at the lower end of the furnace body 1, the argon valve 8 and the air valve 9 are installed at the lower right end of the outer side of the furnace body 1; the cooling system is installed in the furnace body 1, one end of the lower pull rod 4 is sealed and slides through the cooling system and extends to the upper part of the furnace body 1, the other end of the lower pull rod 4 is connected to the lower elevator 6 located in the stand assembly 11, and one end of the upper pull rod 3 is connected to the lower elevator 6 located in the stand assembly 11. After the seal slides on the furnace body 1, it extends to the lower part of the furnace body 1, and the other end of the upper pull-out rod 3 is connected to the upper elevator 5; the heating system 10 is installed in the middle of the furnace body 1 and is located at the upper end of the cooling system, and the heating system 10 is cooled by water; the left amplitude rod 15 and the right amplitude rod 16 are arranged symmetrically with the lower pull-out rod 4 as the center, and the right end of the left amplitude rod 15 contacts the lower pull-out rod 4 through the left tool head 17, the left end of the left amplitude rod 15 is located outside the furnace body 1 and connected to the left transducer 13, the left end of the right amplitude rod 16 contacts the lower pull-out rod 4 through the right working head 18, and the right end of the right amplitude rod 16 is located outside the furnace body 1 and connected to the right transducer 14; the main control cabinet 19 is electrically connected to the upper elevator 5, the lower elevator 6, the heating system 10, the left transducer 13 and the right transducer 14 respectively.

[0048] The horn of this embodiment passes through the furnace body and the cooling chamber and is sealed with the furnace body and the cooling chamber.

[0049] The master control cabinet in this embodiment contains a heating control system, an ultrasonic control system, an elevator control system, and a vacuum system. The heating control system is responsible for setting the heating time, heating power, and holding time and power. The ultrasonic control system is responsible for controlling the ultrasonic vibration power, while the elevator control system adjusts the position of the upper and lower pull rods and controls the speed and distance of the pull. The vacuum system is responsible for extracting air from the device to provide a working environment.

[0050] Specific implementation method 2: Combination Figure 1 and Figure 2 To illustrate this embodiment, this embodiment also includes a furnace door 2, which is connected to the furnace body 1 through a screw-bolt locking device 26. The top of the furnace body 1 is equipped with a top observation window 22 through a top observation window pressure cover 23, and the front of the furnace body 1 is equipped with a front observation window 24 through a front observation window pressure cover 25.

[0051] Thus configured, the screw-bolt locking device 26 in this embodiment is used to open and close the furnace door and lock it during operation. The top observation window 22 and the front observation window 24 are used to monitor for leaks within the furnace. Other components and connections are identical to those in the first embodiment.

[0052] Specific implementation method three: Combination Figure 3 To illustrate this embodiment, the heating system 10 of this embodiment includes a seven-turn square-section electromagnetic induction coil 27, a heat-resistant protective sleeve 28, a cylindrical heating element 29, a crucible 30 and an alloy billet 31; the alloy billet 31 is installed in the crucible 30, the cylindrical heating element 29 is mounted on the outside of the crucible 30, the heat-resistant protective sleeve 28 is mounted on the outside of the cylindrical heating element 29, and the seven-turn square-section electromagnetic induction coil 27 is mounted on the outside of the heat-resistant protective sleeve 28.

[0053] With this configuration, crucible 30 is a refractory crucible. Using an electromagnetic induction coil with a square cross-section instead of a circular cross-section can increase the heating area, thereby improving the heating efficiency of the product. Electromagnetic induction coils with rectangular cross-sections are more easily able to change the emission flow than those with circular cross-sections, reducing energy consumption. This also makes the space used more efficient and the temperature of the heated surface more uniform. When the heating area is the same, preparing an induction coil with a rectangular cross-section is the most material-efficient, and the heat-transmitting layer is more uniform. Other components and connection relationships are the same as those in Specific Embodiments 1 or 2.

[0054] Specific implementation method four: Combination Figure 3 To illustrate this embodiment, the distance between the seven-turn square cross-section electromagnetic induction coil 27 and the heat-resistant protective sleeve 28 is 15 mm, the distance between the heat-resistant protective sleeve 28 and the cylindrical heating element 29 is 10 mm, and the distance between the cylindrical heating element 29 and the crucible 30 is 8 mm.

[0055] Specific implementation method five: Combination Figure 3 To describe this embodiment, the seven-turn square cross-section electromagnetic induction coil 27 of this embodiment is made of copper and is cooled by water.

[0056] This arrangement uses a square-cross-section electromagnetic induction coil instead of a circular-cross-section one. Square-cross-section coils offer the advantages of easier variation of emission flux, reduced energy consumption, and more efficient use of space. They also ensure uniform heating surface temperature and a uniform heat-transmitting layer. For the same heating area, rectangular-cross-section induction coils are the most material-efficient, reducing waste. Other components and connections are the same as those in any of the first to fourth embodiments.

[0057] The seven-turn square cross-section electromagnetic induction coil in this embodiment can also perform heat treatment operations on the alloy round rod prepared by directional solidification with bidirectional ultrasonic vibration applied, thereby further improving the mechanical properties of the alloy.

[0058] Specific implementation method six: combination Figure 1 and Figure 3 This embodiment will be described. The cooling system of this embodiment includes a cooling chamber 12 , a cooling cover 20 , and a Ga—In solution 21 . The cooling cover 20 is mounted on the cooling chamber 12 , and the cooling chamber 12 is filled with the Ga—In solution 21 .

[0059] With this arrangement, the liquid in the water inlet pipe and the liquid in the water outlet pipe are cooling water. The inlet and outlet water are filled with cooling water to cool the seven-turn square cross-section electromagnetic induction coil. This prevents the electromagnetic induction coil from damaging the seven-turn square cross-section electromagnetic induction coil when heated. The role of the Ga-In coolant is to immerse the pulled out alloy ingot into a liquid metal Ga-In alloy liquid with a high boiling point, low melting point, and large heat capacity, which has a high thermal conductivity. This allows the pulled out alloy long rod to be quickly cooled and solidified. The coolant needs to meet the following conditions: 1) low melting point and good thermal properties; 2) insoluble in the alloy; 3) low vapor pressure and can be used under high vacuum conditions; 4) cheap. The Ga-In alloy liquid meets the above conditions.

[0060] Specific implementation method seven: combination Figure 1 and Figure 3 To illustrate this embodiment, the cooling system of this embodiment further includes a water inlet pipe 32, a water outlet pipe 33, a water inlet interface 34, a water outlet interface 35, a water inlet pipe plug-in plate 36, and a water outlet pipe plug-in plate 37;

[0061] One end of the water inlet pipe 32 and the water outlet pipe 33 are connected to the induction coil 27 through the water inlet interface 34 and the water outlet interface 35 respectively, and the other ends of the water inlet pipe 32 and the water outlet pipe 33 are connected to the water inlet pipe plug-in plate 36 and the water outlet pipe plug-in plate 37 respectively.

[0062] Thus configured, the induction coil cooling system, consisting of the water inlet pipe 32, the water outlet pipe 33, the water inlet port 34, and the water outlet port 35, primarily ensures a continuous flow of cooling water through the seven-turn electromagnetic induction coil through water inlet and outlet, cooling the seven-turn electromagnetic induction coil and preventing damage to the electromagnetic induction coil from heat generated during heating. The remaining components and connections are the same as those of any of the first to sixth embodiments.

[0063] Specific implementation method eight: combination Figure 3 To describe this embodiment, the outlet pipe plug-in plate 37 and the inlet pipe plug-in plate 36 of this embodiment are respectively installed on the inner side wall of the furnace body 1.

[0064] Such a configuration has a simple structure and is convenient and reliable to connect. Other components and connection relationships are the same as any one of the specific embodiments 1 to 4.

[0065] Specific implementation method nine: combination Figures 1 to 3 The present embodiment describes a method for preparing a high-temperature alloy, which includes the following steps:

[0066] Step 1: Adjust the position of the lower pull rod 4;

[0067] Adjust the upper end surface of the lower pull rod 4 through the main control cabinet 19 to align with the upper plane of the cooling chamber 12;

[0068] Step 2: Determine the position of the crucible 30;

[0069] Step 21: Cut an alloy blank 31 from the alloy base material. The alloy blank 31 is a cylindrical alloy raw material and is placed in a crucible 30. The crucible 30 is divided into a crucible body and a crucible cover. After the cylindrical alloy raw material is placed in the crucible body, the crucible cover is sealed.

[0070] Step 22: Place the crucible 30 directly above the upper end surface of the lower pull rod 4 in the furnace body 1; at this time, adjust the main control cabinet 19, lower the upper pull rod 3 and press it against the upper end surface of the crucible 30, while ensuring that the crucible 30 does not move out of the relative position during the simultaneous movement of the upper pull rod 3 and the lower pull rod 4;

[0071] Step 3: Debug the cooling system:

[0072] After adjusting the positions of the components, close the furnace door 2 and tighten the screw bolts 26 to prevent air leakage. Turn on the cooling system and observe whether there is water seepage in the furnace body 1 through the top observation window 22 and the front observation window 25. If there is water seepage, stop the preparation and seal the furnace body 1. If there is no water seepage, proceed to the next step:

[0073] Step 4: Evacuate the furnace and introduce argon gas into the furnace body 1:

[0074] Use a vacuum pump to evacuate the furnace body 1 to -0.1 MPa, and continue evacuating the furnace body 1 using a molecular pump until the pressure inside the furnace body 1 reaches 0.001-0.8. Then, open the argon valve 8 and introduce argon into the furnace body 1 as a protective gas. Observe the pressure gauge 7 and introduce 0.08 MPa of argon into the furnace body 1.

[0075] Step 5: Check again through the top observation window 22 and the front observation window 25 whether there is any water leakage inside the device, and confirm whether the upper pull rod 3 and the lower pull rod 4 are clamping the crucible 30;

[0076] Step 6: Adjust the ultrasonic vibration power of the left transducer 13 and the right transducer 14 through the main control cabinet 19. The ultrasonic vibration power range is 1200-1800W;

[0077] Step 7: Set the heating time and heating power of the heating system 10 through the main control cabinet 19. The adjustable range of the heating time is 0-60min, the adjustable range of the heating power is 25-60kW, the adjustable range of the holding time is 0-48h, and the holding power is 2-12W;

[0078] Step 8: Set the pulling speed of the upper pulling rod 3 and the lower pulling rod 4 to 80-150 μm / s through the main control cabinet 19;

[0079] Step 9: After setting all parameters, the main control cabinet 19 starts the induction heating of the heating system 10, then starts the ultrasonic vibration of the left transducer 13 and the right transducer 14, and finally starts the pulling movement of the upper pulling rod 3 and the lower pulling rod 4;

[0080] Step 10: After the pulling movement is completed, the heating system 10 is turned off through the main control cabinet 19. If heat treatment is required, the heating system 10 is not turned off; the ultrasonic vibrations of the left transducer 13 and the right transducer 14 are turned off, and the positions of the upper pulling rod 3 and the lower pulling rod 4 are adjusted to restore the crucible 30 to the position of the lower pulling rod 4 in step 1;

[0081] Step 11: Adjust the position of the upper pull rod 3 through the main control cabinet 19, open the air valve 9, fill air into the interior of the furnace body 1, and unscrew the screw bolt locking device 26. After waiting for the temperature inside the furnace body 1 to cool down, open the furnace door 2, take out the crucible 30, and take out the high-temperature alloy round rod prepared by combining the bidirectional ultrasonic vibration formed by the left transducer 13 and the right transducer 14 in the furnace body 1 with directional solidification. At this point, the preparation of the high-temperature alloy is completed.

[0082] During the directional solidification process, the vibration of the horn on the crucible introduces ultrasonic waves into the solid-liquid interface of the ingredients during directional solidification, breaking the drawn-out, elongated primary phase. Under the action of the ultrasound, the broken primary phase is distributed throughout the microstructure. This improves the strong anisotropy of the mechanical properties of alloys produced by directional solidification and enhances the alloy's mechanical properties.

[0083] A centrally symmetrical bidirectional ultrasonic action is applied to the position of the directional solidification solid-liquid interface, that is, the entire area of ​​the melt is covered to prevent the problem of incomplete action area of ​​unidirectional ultrasonic waves. The bidirectional ultrasonic wave generates a standing wave field in the alloy melt, making it easy for long strip phases of different orientations to grow at the position of the wave nodes, and then present a periodic arrangement, further weakening the anisotropy of the mechanical properties of the alloy prepared by directional solidification and improving the mechanical properties of the alloy.

[0084] The present invention directly extends the horn and the tool head into the cooling chamber cavity, brings the tool head into contact with the crucible, indirectly introduces bidirectional ultrasonic waves into the alloy melt, and directly cools the horn and the tool head through the Ga-In liquid, so that ultrasonic waves can be introduced into the high-temperature alloy melt, thereby balancing the working temperature of the horn and the tool head with the problem of ultrasonic attenuation caused by the indirect introduction of ultrasonic waves.

[0085] Specific implementation method ten: Combination Figure 1 4( a ) and FIG. 4( a ) illustrate this embodiment. The high-temperature alloy raw material of this embodiment is a Nb-16Si-20Zr-2C high-temperature alloy.

[0086] The alloy system of this embodiment covers all high-temperature alloys. The alloy composition of the specific example given in the embodiment is Nb-16Si-20Zr-2C high-temperature alloy.

[0087] Combined with Figure 4(a), Figure 4(b) and Figure 5 The inventive effects of this embodiment are demonstrated by examining the microstructure of a Nb-16Si-20Zr-2C alloy prepared using a vacuum non-consumable arc furnace. The results show that its microstructure consists of large, nearly hexagonal, primary γNb5Si3 phases, a γNb5Si3 / Nbss eutectoid structure, and small Nbss phases. Coarse, nearly hexagonal primary γNb5Si3 phases are distributed throughout the microstructure. Fine γNb5Si3 / Nbss eutectoid structures surround the massive γNb5Si3 phases. A Nb-16Si-20Zr-2C alloy prepared using a combination of ultrasonic vibration and directional solidification also exhibits a microstructure composed of primary γNb5Si3 phases, a γNb5Si3 / Nbss eutectoid structure, and small Nbss phases. However, the γNb5Si3 phases are elongated in shape because the directional solidification process initially crystallizes into columnar, elongated forms. Secondly, under the action of bidirectional ultrasound, the long strips of γNb5Si3 phase are dispersed to various parts of the melt along with the acoustic streaming. The standing wave field formed by the combined action of bidirectional ultrasound causes the alloy's long strips of primary γNb5Si3 phases with different orientations to grow at the locations of the standing wave nodes. This structure is conducive to solving the anisotropy in the mechanical properties of high-temperature alloys. This structure can effectively improve the room temperature fracture toughness of the alloy. It can be seen that the room temperature fracture toughness of Nb-16Si-20Zr-2C prepared by melting in a conventional vacuum non-consumable arc furnace is 13.1MPa·m 1 / 2 The room temperature fracture toughness of the Nb-16Si-20Zr-2C alloy prepared by combining ultrasonic vibration with directional solidification is 15.9 MPa·m 1 / 2The room temperature fracture toughness perpendicular to the directional solidification direction is 15.5 MPa·m 1 / 2 The difference is not big, which effectively solves the anisotropy of mechanical properties.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A solidification device for preparing high-temperature alloys by combining bidirectional ultrasonic vibration with directional solidification, characterized by: It includes a furnace body (1), a furnace door (2), an upper pull rod (3), a lower pull rod (4), an upper elevator (5), a lower elevator (6), a pressure gauge (7), an argon valve (8), an air valve (9), a heating system (10), a stand assembly (11), a cooling system, a left transducer (13), a right transducer (14), a left horn (15), a right horn (16), a left tool head (17), a right tool head (18) and a main control cabinet (19); The pressure gauge (7) is installed on the outer left end surface of the furnace body (1), the stand assembly (11) is installed at the lower end of the furnace body (1), and the argon valve (8) and the air valve (9) are installed at the lower right end of the outer side of the furnace body (1); The cooling system is installed in the furnace body (1), one end of the lower pull rod (4) is sealed and slid through the cooling system and then extends to the upper part of the furnace body (1), the other end of the lower pull rod (4) is connected to the lower elevator (6) located in the stand assembly (11), one end of the upper pull rod (3) is sealed and slidably installed on the furnace body (1) and then extends to the lower part of the furnace body (1), and the other end of the upper pull rod (3) is connected to the upper elevator (5); The heating system (10) is installed in the middle of the furnace body (1) and located at the upper end of the cooling system, and the heating system (10) is cooled by water; The left amplitude changing rod (15) and the right amplitude changing rod (16) are symmetrically arranged with the lower pull rod (4) as the center, and the right end of the left amplitude changing rod (15) contacts the lower pull rod (4) through the left tool head (17), the left end of the left amplitude changing rod (15) is located outside the furnace body (1) and is connected to the left transducer (13), the left end of the right amplitude changing rod (16) contacts the lower pull rod (4) through the right tool head (18), and the right end of the right amplitude changing rod (16) is located outside the furnace body (1) and is connected to the right transducer (14); The main control cabinet (19) is electrically connected to the upper elevator (5), the lower elevator (6), the heating system (10), the left transducer (13) and the right transducer (14); The heating system (10) includes a seven-turn square-section electromagnetic induction coil (27), a heat-resistant protective sleeve (28), a cylindrical heating element (29), a crucible (30), and an alloy blank (31); The alloy blank (31) is installed in the crucible (30), the cylindrical heating element (29) is mounted on the outside of the crucible (30), the heat-resistant protective sleeve (28) is mounted on the outside of the cylindrical heating element (29), and the seven-turn square cross-section electromagnetic induction coil (27) is mounted on the outside of the heat-resistant protective sleeve (28); The cooling system comprises a cooling chamber (12), a cooling cover (20) and a Ga-In liquid (21), wherein the cooling cover (20) is mounted on the cooling chamber (12), and the cooling chamber (12) is filled with the Ga-In liquid (21); The left amplitude changing rod (15), the right amplitude changing rod (16), the left tool head (17) and the right tool head (18) extend into the cooling chamber (12); the high temperature alloy is a Nb-Si alloy.

2. The solidification equipment for preparing high-temperature alloys by combining bidirectional ultrasonic vibration with directional solidification according to claim 1, characterized in that: The furnace door (2) is connected to the furnace body (1) by a screw-fastening bolt locking device (26). The top of the furnace body (1) is provided with a top observation window (22) via a top observation window gland (23). The front of the furnace body (1) is provided with a front observation window (24) via a front observation window gland (25).

3. The solidification equipment for preparing high-temperature alloys by combining bidirectional ultrasonic vibration with directional solidification according to claim 2, characterized in that: The distance between the seven-turn square cross-section electromagnetic induction coil (27) and the heat-resistant protective sleeve (28) is 15 mm, the distance between the heat-resistant protective sleeve (28) and the cylindrical heating element (29) is 10 mm, and the distance between the cylindrical heating element (29) and the crucible (30) is 8 mm.

4. The solidification equipment for preparing high-temperature alloys by combining bidirectional ultrasonic vibration with directional solidification according to claim 3, characterized in that: The seven-turn square cross-section electromagnetic induction coil (27) is made of copper and is cooled by water.

5. The solidification equipment for preparing high-temperature alloys by combining bidirectional ultrasonic vibration with directional solidification according to claim 4, characterized in that: The cooling system further includes a water inlet pipe (32), a water outlet pipe (33), a water inlet interface (34), a water outlet interface (35), a water inlet pipe plug-in plate (36), and a water outlet pipe plug-in plate (37); One end of the water inlet pipe (32) and the water outlet pipe (33) are connected to the induction coil (27) through the water inlet interface (34) and the water outlet interface (35), respectively, and the other ends of the water inlet pipe (32) and the water outlet pipe (33) are connected to the water inlet pipe plug-in plate (36) and the water outlet pipe plug-in plate (37), respectively.

6. The solidification equipment for preparing high-temperature alloys by combining bidirectional ultrasonic vibration with directional solidification according to claim 5, characterized in that: The water outlet pipe plug-in plate (37) and the water inlet pipe plug-in plate (36) are respectively installed on the inner side wall of the furnace body (1).

7. A method for preparing a high-temperature alloy using the solidification equipment for preparing a high-temperature alloy by combining bidirectional ultrasonic vibration with directional solidification as claimed in claim 6, characterized in that: It includes the following steps: Step 1: Adjust the position of the lower pull rod (4); Adjust the upper end surface of the lower pull rod (4) through the main control cabinet (19) to align with the upper plane of the cooling chamber (12); Step 2: Determine the position of the crucible (30); Step 21: Cut an alloy blank (31) from the alloy base material. The alloy blank (31) is a cylindrical alloy raw material and is placed in a crucible (30). The crucible (30) is composed of a crucible body and a crucible cover. After the alloy blank is placed in the crucible body, the cover of the crucible (30) is sealed. Step 22: Place the crucible (30) just above the upper end face of the lower pull rod (4) in the furnace body (1); at this time, adjust the main control cabinet (19), lower the upper pull rod (3) and press it against the upper end face of the crucible (30), and ensure that the crucible (30) does not move away from the relative position during the simultaneous movement of the upper pull rod (3) and the lower pull rod (4); Step 3: Debug the cooling system: After adjusting the positions of the components, close the furnace door (2) and use the screw-bolt locking device (26) to prevent air leakage. Open the cooling system and observe whether there is water seepage in the furnace body (1) through the top observation window (22) and the front observation window (24). If there is water seepage, stop the preparation and seal the furnace body (1). If there is no water seepage, proceed to the next step: Step 4: Evacuate the furnace and introduce argon gas into the furnace (1): Use a vacuum pump to evacuate the furnace body (1) to -0.1 MPa, and continue evacuating the furnace body (1) using a molecular pump until the pressure inside the furnace body (1) reaches 0.001 Pa-0.8 Pa. Then, open the argon valve (8) and introduce argon into the furnace body (1) as a protective gas. Observe the pressure gauge (7) and introduce 0.08 MPa of argon into the furnace body (1). Step 5: Check again through the top observation window (22) and the front observation window (24) whether there is any water leakage inside the device, and confirm whether the upper pull rod (3) and the lower pull rod (4) are clamping the crucible (30); Step 6: Adjust the ultrasonic vibration power of the left transducer (13) and the right transducer (14) through the main control cabinet (19), and the ultrasonic vibration power range is 1200-1800W; Step 7: Set the heating time and heating power of the heating system (10) through the main control cabinet (19). The adjustable range of the heating time is 0-60 minutes, the adjustable range of the heating power is 25-60kW, the adjustable range of the holding time is 0-48 hours, and the holding power is 2-12W. Step 8: Setting the pulling speed of the upper pulling rod (3) and the lower pulling rod (4) to 80-150 μm / s through the main control cabinet (19); Step 9: After setting all parameters, start the induction heating of the heating system (10) through the main control cabinet (19), then start the ultrasonic vibration of the left transducer (13) and the right transducer (14), and finally start the pulling movement of the upper pulling rod (3) and the lower pulling rod (4); Step 10: After the pulling and drawing movement is completed, the heating system (10) is turned off through the main control cabinet (19). If heat treatment is required, the heating system (10) is not turned off; the ultrasonic vibration of the left transducer (13) and the right transducer (14) is turned off, and the positions of the upper pulling rod (3) and the lower pulling rod (4) are adjusted to restore the crucible (30) to the position of the lower pulling rod (4) in step 1; Step 11: Adjust the position of the upper pull rod (3) through the main control cabinet (19), open the air valve (9), fill air into the interior of the furnace body (1), and unscrew the screw bolt locking device (26). After waiting for the internal temperature of the furnace body (1) to cool down, open the furnace door (2), take out the crucible (30), and take out the high-temperature alloy round rod prepared by combining the bidirectional ultrasonic vibration formed by the left transducer (13) and the right transducer (14) inside the furnace body (1) with directional solidification. At this point, the preparation of the high-temperature alloy is completed.

8. The method for preparing a high-temperature alloy according to claim 7, characterized in that: The high-temperature alloy raw material is Nb-16Si-20Zr-2C high-temperature alloy.

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