High-temperature-resistant rare earth-doped composite alloy material and preparation method thereof

Abstract

The invention relates to the technical field of rare earth-doped composite alloy preparation, in particular to a high-temperature-resistant rare earth-doped composite alloy material and a preparation method thereof.The preparation method comprises the steps that a consumable electrode is smelted; the reduction amount of the melting speed of the consumable electrode in the smelting process is obtained, and the vacuum pumping speed is adjusted; the falling length of molten drops is obtained, and the direction of an induced magnetic field of a plasma area vertically below the consumable electrode is determined; the stirring rotating speed of the electromagnetic stirring mechanism is determined according to the length ratio of time sections with opposite magnetic field directions in the induced magnetic field direction and the electromagnetic stirring magnetic field direction; a molten pool splashing plane image is obtained, the height section of the corresponding impurities on the consumable electrode is determined, and the working current in the smelting process is adjusted according to the height section; and after the smelting process is completed according to the working current, a generated cast ingot is subjected to thermal machining and heat treatment, and the high-temperature-resistant rare earth-doped composite alloy material is formed. The preparation efficiency of the rare earth doped composite alloy is improved.

Description

Technical Field

[0001] This invention relates to the field of rare earth-doped composite alloy preparation technology, and in particular to a high-temperature resistant rare earth-doped composite alloy material and its preparation method. Background Technology

[0002] High-temperature alloys, especially nickel-based and cobalt-based high-temperature alloys, are key materials for manufacturing hot-end components of high-end equipment such as aero-engines and gas turbines. To further improve the service temperature and durability of high-temperature alloys, the introduction of rare earth elements for microalloying has proven to be an effective technical approach. Traditional smelting technology lacks effective online monitoring methods for the microscopic physical processes occurring in the smelting zone. Defects such as solidified crusts, white spots, and inclusions caused by the shedding of contaminants from the electrode surface and the release of impurity gases can often only be detected after smelting and ingot processing. For the gradual and localized quality deterioration process caused by impurity gases and electromagnetic interference, there is a lack of real-time diagnosis and precise dynamic adjustment capabilities. Therefore, there is an urgent need for a method to prepare high-temperature resistant rare earth-doped composite alloy materials that can sense and precisely control the key physicochemical processes related to the formation of rare earth element behavior in real time during the smelting process.

[0003] Chinese Patent Publication No. CN110479989A discloses a processing method for high-temperature resistant titanium alloy castings. By studying the properties of titanium alloys and casting characteristics, a method is used to melt-add nano-yttrium oxide material prepared by extrusion casting into the titanium alloy. This optimizes the α+β phase microstructure of the titanium alloy, reduces the proportion of unstable microstructures, and transforms it into a fine and uniform lamellar structure. This processing method has high utilization of the molten titanium alloy, eliminates the need for heat treatment strengthening, and produces titanium alloy castings with excellent high-temperature resistance, good heat dissipation, and significantly improved mechanical properties. It can effectively overcome the poor fluidity and general filling ability of titanium alloys, refine grains, eliminate shrinkage cavities in macrostructure and shrinkage porosity in microstructure, and manufacture machined parts with complex shapes and structures. It can also be seen that the processing method of the high-temperature resistant titanium alloy casting has the problem that during the vacuum melting process, the impurity gas is subjected to enhanced regional vibration due to the vacuum above the plasma zone, which leads to an increase in local gas pressure. This, in turn, hinders the upward discharge of the impurity gas, causing the impurity gas to stay in the high-temperature plasma zone for a longer time, which in turn hinders the formation of the electric arc and reduces the stirring effect of the electromagnetic stirring mechanism. Summary of the Invention

[0004] To address this issue, the present invention provides a high-temperature resistant rare-earth-doped composite alloy material and its preparation method, thereby overcoming the problem in the prior art where, during vacuum melting, the impurity gas undergoes enhanced regional vibration due to vacuuming above the plasma zone, leading to increased local gas pressure, which in turn hinders the upward discharge of subsequent impurity gas, causing the impurity gas to remain in the high-temperature plasma zone for a longer period, thus hindering the formation of an electric arc and resulting in a decrease in the stirring effect of the electromagnetic stirring mechanism.

[0005] On one hand, the present invention provides a method for preparing a high-temperature resistant rare-earth-doped composite alloy material, comprising: The consumable electrode, which is composed of electrode ingots output from a vacuum induction melting furnace, is melted in a vacuum environment. The amount by which the melting rate of the consumable electrode decreases during the smelting process is obtained; Adjust the vacuum pumping speed according to the amount of decrease in the melting rate; Obtain the droplet length after adjusting the vacuum pumping speed; The direction of the induced magnetic field in the plasma region vertically below the consumable electrode is determined based on the droplet's fall length. The directions of the induced magnetic field and the electromagnetic stirring magnetic field of the electromagnetic stirring mechanism around the self-consuming electrode are obtained respectively within a unit magnetic field monitoring cycle. The stirring speed of the electromagnetic stirring mechanism is determined based on the proportion of time intervals in which the directions of the induced magnetic field and the electromagnetic stirring magnetic field are opposite. Obtain a planar image of the molten pool splash on the water-cooled copper crucible after adjusting the stirring speed as described; Based on the planar image, determine the height segment corresponding to the impurity on the consumable electrode; The operating current of the smelting process is adjusted according to the height range; After the melting process is completed according to the operating current, the resulting ingot is subjected to thermomechanical processing and heat treatment in sequence to form a high-temperature resistant rare earth-doped composite alloy material.

[0006] Further, adjusting the vacuum pumping speed according to the decrease in the melting rate includes: The reduction in melting speed is compared with a preset reduction. If the reduction is greater than the preset reduction, it is determined that the increased vibration caused by vacuum pumping reduces the upward velocity of the impurity gas and decreases the vacuum pumping speed. The reduction is the difference between the melting rate at the beginning and the melting rate at the end of a unit monitoring cycle. The vacuum pumping speed is negatively correlated with the reduction amount.

[0007] Further, determining the direction of the induced magnetic field in the plasma region vertically below the consumable electrode based on the droplet's fall length includes: Obtain the fall length of several individual molten droplets within the droplet fall time interval; If the difference between the length of the first molten droplet falling at the previous moment and the length of the second molten droplet falling at the next moment in a single time point of the molten droplet falling time segment is greater than a second preset difference, the direction of the induced magnetic field is determined to be vertically downward. If the difference is less than the first preset difference, the direction of the induced magnetic field is determined to be vertically upward.

[0008] Furthermore, the second preset difference is greater than the first preset difference.

[0009] Further, determining the stirring speed of the electromagnetic stirring mechanism based on the proportion of time intervals in which the magnetic field directions are opposite in the induced magnetic field direction and the electromagnetic stirring magnetic field direction includes: Compare the percentage of the time segment length with the preset percentage; If the length of the time segment is greater than the preset percentage, it is determined that the influence of the induced magnetic field on the electromagnetic stirring mechanism does not meet the requirements, and the stirring speed of the electromagnetic stirring mechanism is increased.

[0010] Furthermore, the stirring speed is positively correlated with the proportion of the time interval length.

[0011] Further, the time interval length ratio is the ratio of the length of the time interval with opposite magnetic field directions to the length of the time interval lasting for a unit magnetic field monitoring cycle, wherein, The opposite directions of the magnetic fields include: Within a unit magnetic field monitoring cycle, the induced magnetic field is vertically downward, and the electromagnetic stirring magnetic field is vertically upward. Within a unit magnetic field monitoring cycle, the induced magnetic field is vertically upward, and the electromagnetic stirring magnetic field is vertically downward.

[0012] Further, determining the height segment of the impurity on the consumable electrode based on the planar image includes: Compare the maximum area of ​​the molten pool in the planar image of the molten pool splash with a preset area; If the maximum area of ​​the molten pool is less than or equal to the preset area, it is determined that the degree of influence of impurities on the molten droplets does not meet the requirements. The vertical height range on the consumable electrode corresponding to the time period when the maximum area of ​​the molten pool is less than the preset area is determined as the height range corresponding to the impurity on the consumable electrode.

[0013] Furthermore, adjusting the current of the smelting process according to the height range includes: The length of the height segment is compared with the preset length; If the length of the height segment is greater than the preset length, the current in the smelting process is reduced, wherein... The current is negatively correlated with the length of the height segment.

[0014] On the other hand, the present invention provides a method for preparing a high-temperature resistant rare earth-doped composite alloy material. The rare earth-doped composite alloy material comprises 50 wt% to 70 wt% of matrix elements, 5 wt% to 20 wt% of solid solution strengthening elements, 2 wt% to 12 wt% of precipitation strengthening elements, less than 1 wt% of grain boundary strengthening elements, and less than 0.1 wt% of rare earth elements.

[0015] Compared with the prior art, the beneficial effect of the present invention is that, by obtaining the decrease in the melting rate of the consumable electrode during the smelting process, the present invention characterizes the increased vibration at the interface area caused by the weakened connectivity between the electrode clamping mechanism and the gas extraction pipe interface due to repeated vacuuming above the plasma zone. This results in an increase in the temperature of the gas trapped in this area, making the temperature of the electrode rod surface above the plasma zone higher than before, and consequently, the gas pressure in the plasma zone higher than before. This makes it more difficult for the impurity gas to move upward, thus causing the impurity gas to remain trapped in the plasma zone below the consumable electrode. Impurity gases hinder the formation of the electric arc in the vertical region where they are located, thus slowing down the melting rate at the melting position corresponding to the impurity gas region. When this reduction is greater than the preset reduction, it indicates that the falling length of the molten droplets caused by the slowed melting rate of the consumable electrode tends to shorten overall. Therefore, by reducing the vacuum pumping speed, the gas volume flow rate in the region where the electrode clamping mechanism and the pumping pipe interface are reduced, thereby mitigating the vibration enhancement caused by high-speed airflow. This further eliminates the local gas blockage effect of impurity gases trapped in the plasma region below the consumable electrode, improves the melting efficiency of the consumable electrode, and thus improves the preparation efficiency of rare earth-doped composite alloys.

[0016] Furthermore, this invention determines the direction of the induced magnetic field in the plasma region vertically below the consumable electrode based on the droplet's fall length. When the difference between the first droplet fall length at the previous moment and the second droplet fall length at the next moment within a single time point of the droplet fall time segment is greater than a second preset difference, it indicates that the droplet can be stretched to a longer size before detaching, and the direction of the induced magnetic field is vertically downward. When this difference is less than the first preset difference, it indicates that the droplet is subjected to a stronger constraint and detaches earlier, meaning that the electromagnetic environment of the plasma region is developing in the direction of arc contraction, and the direction of the induced magnetic field is vertically upward. When the proportion of time segments with opposite magnetic field directions in the induced magnetic field direction and the electromagnetic stirring magnetic field direction is greater than a preset proportion, it proves that the droplet fall length caused by impurity gas has changed compared to the normal fall length, causing the released impurity gas to form a local low conductivity region within the plasma region, hindering... Disrupting the normal current path forces the electric arc to find an alternative path, thereby altering the natural distribution of the electromagnetic field. If the electromagnetic stirring mechanism continues to stir at a fixed speed, the rotating magnetic field generated by the stirring mechanism will conflict directionally with the electromagnetic field of the disturbed plasma region, generating mutually canceling Lorentz forces, which reduces stirring efficiency. This reduction in stirring efficiency further exacerbates microsegregation, macroscopically manifested as thickening of the ingot's solidified shell and the occurrence of non-sequential solidification. By increasing the stirring speed of the electromagnetic stirring mechanism according to the increased proportion of the time interval between the induced magnetic field direction and the electromagnetic stirring magnetic field direction being opposite, the efficiency loss caused by the directional conflict between the rotating magnetic field generated by the stirring mechanism and the inherent electromagnetic field of the disturbed plasma region can be compensated. This promotes the homogenization of the temperature and concentration fields in the molten pool, thereby reducing microsegregation and restoring the normal sequential solidification process, improving the melting efficiency of the consumable electrode, and thus improving the preparation efficiency of rare earth-doped composite alloys.

[0017] Furthermore, this invention characterizes the phenomenon by indicating that, due to the vacuuming vibration causing impurity gases trapped in the plasma region to be re-ventilated and removed by vacuum, some impurity components condense and adhere to the surface of the consumable electrode along the path of removal. When the consumable electrode melts to the location where the impurities adhere, impurity-containing droplets form and fall. Because the impurity components alter the physical properties of the droplets—that is, impurity elements act as surface-active substances and agglomerate on the droplet surface—the droplets containing impurities tend to cluster upon impact with the molten pool due to decreased surface tension and increased viscosity. This results in a concentrated spatter area, manifested in the planar image of the molten pool spatter as a small maximum area of ​​the molten pool. Therefore, when the maximum area of ​​the molten pool is detected to be smaller than the preset area, it is determined that the degree of influence of impurities due to the change in the physical properties of the molten droplets caused by impurities attached to the electrode surface does not meet the requirements. Then, based on the vertical height range on the consumable electrode corresponding to the time period when the maximum area of ​​the molten pool is smaller than the preset area, the length of the height segment corresponding to the impurities on the consumable electrode is determined, and the current of the melting process is reduced. This allows the molten droplets containing impurities to enter the molten pool in a more dispersed form, reducing the instantaneous impact on the molten pool. This sequential solidification method can push the remaining small impurities to the last solidification area of ​​the ingot, such as the top area of ​​the ingot, thereby further improving the uniformity of the ingot and the purity of the ingot material, and thus improving the preparation efficiency of rare earth-doped composite alloys. Attached Figure Description

[0018] Figure 1 This is an overall flow chart of the preparation method of the high-temperature resistant rare earth-doped composite alloy material according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a vacuum consumable arc furnace for the preparation method of high-temperature resistant rare-earth-doped composite alloy materials according to an embodiment of the present invention. Figure 3 This is a flowchart illustrating the determination of the induced magnetic field direction in the preparation method of high-temperature resistant rare-earth-doped composite alloy materials according to an embodiment of the present invention. Figure 4 This is a flowchart illustrating the determination of the height segment corresponding to the impurities on the consumable electrode in the preparation method of the high-temperature resistant rare-earth-doped composite alloy material according to an embodiment of the present invention. Explanation of reference numerals in the attached drawings: 1-consumable electrode, 2-electrode clamping rod, 3-first industrial camera, 4-second industrial camera, 5-vacuum pump, 6-water-cooled copper crucible, 7-displacement encoder, 8-electromagnetic stirrer, 9-height section. Detailed Implementation

[0019] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0020] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0021] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0022] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Please see Figure 1 The diagram shown is an overall flow chart of the preparation method of the high-temperature resistant rare-earth-doped composite alloy material according to an embodiment of the present invention; the preparation method of the high-temperature resistant rare-earth-doped composite alloy material according to an embodiment of the present invention includes: Step S1: Melt the consumable electrode made of electrode ingots output from the vacuum induction melting furnace in a vacuum environment. Step S2: Obtain the amount of decrease in the melting rate of the consumable electrode during the smelting process; Step S3: Adjust the vacuum pumping speed according to the decrease in melting speed; Step S4: Obtain the droplet length after adjusting the vacuum pumping speed; Step S5: Determine the direction of the induced magnetic field in the plasma region vertically below the consumable electrode based on the falling length of the molten droplet. Step S6: Obtain the direction of the induced magnetic field and the direction of the electromagnetic stirring magnetic field of the electromagnetic stirring mechanism around the self-consuming electrode within a unit magnetic field monitoring cycle. Step S7: Determine the stirring speed of the electromagnetic stirring mechanism based on the proportion of time intervals in which the magnetic field directions of the induced magnetic field and the electromagnetic stirring magnetic field are opposite. Step S8: Obtain a planar image of the molten pool splash on the water-cooled copper crucible after adjusting the stirring speed as described; Step S9: Determine the height segment of the impurity on the consumable electrode based on the planar image; Step S10: Adjust the working current of the smelting process according to the height range; Step S11: After the melting process is completed according to the working current, the generated ingot is subjected to thermomechanical processing and heat treatment in sequence to form a high-temperature resistant rare earth-doped composite alloy material.

[0024] Specifically, the vacuum environment is a vacuum environment with an absolute pressure of 0.1 Pa to 10 Pa established in a vacuum self-consuming arc melting furnace.

[0025] Specifically, the consumable electrode is smelted at 1500–1800°C.

[0026] Specifically, the melting process of the consumable electrode 1, which is composed of electrode ingots, is completed in a vacuum consumable arc furnace.

[0027] As will be understood by those skilled in the art, the operating principle and process of the vacuum self-consuming electric arc melting furnace are conventional technical means well known to those skilled in the art, therefore the operating principle and process of the vacuum self-consuming electric arc melting furnace will not be described in detail here.

[0028] Specifically, the electrode ingot is a rare earth metal blank containing gas and impurities, as well as non-metallic inclusions, and exhibiting casting defects such as shrinkage cavities and porosity.

[0029] Specifically, the gases contained in the electrode ingot include, but are not limited to, hydrogen, oxygen, and nitrogen.

[0030] Specifically, the impurities contained in the electrode ingots include, but are not limited to, lead, bismuth, tellurium, thallium, sulfur, phosphorus, arsenic, antimony, tin, and selenium.

[0031] Specifically, the non-metallic inclusions contained in the electrode ingot include, but are not limited to, alumina, silicon oxide, titanium oxide, calcium aluminate, spinel, titanium nitride, aluminum nitride, titanium carbide, niobium carbide, tantalum carbide, manganese sulfide, and titanium sulfide.

[0032] Specifically, the diameter of the consumable electrode 1 is 420 mm, and the length of the consumable electrode 1 is 1.5 m to 3 m.

[0033] Please see Figure 2 As shown, this is a schematic diagram of the vacuum consumable arc furnace used in the preparation method of high-temperature resistant rare-earth-doped composite alloy materials according to an embodiment of the present invention. The vacuum consumable arc furnace includes: A water-cooled copper crucible 6 is placed below the consumable electrode 1 to cool the outer shell of the ingot during the solidification process. The displacement encoder 7 is connected to the electrode clamping rod 2 to obtain the position change of the consumable electrode 1 and calculate the melting rate of the consumable electrode 1 based on the position change of the consumable electrode 1. The first industrial camera 3 is set on top of the vacuum consumable arc furnace to obtain a planar image of the molten pool splash in the droplet formation area at the end of the consumable electrode 1. The second industrial camera 4, together with the first industrial camera 3, constitutes a binocular stereo vision system to obtain the falling length of the molten droplet; Vacuum pump 5 is used to adjust the vacuum pumping speed in the vacuum consumable arc furnace.

[0034] Specifically, vacuum pump 5 also includes Roots pump and dry screw pump.

[0035] As will be understood by those skilled in the art, the operating principles and processes of Roots pumps and dry screw pumps are conventional technical means well known to them, and therefore will not be elaborated upon here.

[0036] Specifically, the electromagnetic stirring mechanism is used to generate a rotating magnetic field, which includes an electromagnetic stirrer 8 integrated inside the water-cooled copper crucible 6 and a magnetic field generator (not shown in the figure).

[0037] In practice, this invention characterizes the decrease in the melting rate of the consumable electrode during the smelting process by measuring the reduction in the melting rate of the consumable electrode. This is due to the weakened connectivity between the electrode clamping mechanism and the gas extraction pipe interface caused by repeated vacuuming above the plasma zone, resulting in increased vibration at the interface. Consequently, the temperature of the gas trapped in this area increases, leading to a higher temperature between the electrode rod surface above the plasma zone and the water-cooled furnace wall. This, in turn, increases the gas pressure in the plasma zone, making it more difficult for impurity gases to move upward. Consequently, impurity gases become trapped in the plasma zone below the consumable electrode, hindering the upward movement of impurity gases. The formation of an electric arc in the vertical region where the impurity gas is located slows down the melting rate at the melting position corresponding to the region where the impurity gas is located. When this reduction is greater than the preset reduction, it indicates that the falling length of the molten droplets caused by the slow melting rate of the consumable electrode shows an overall shortening trend. Therefore, by reducing the vacuum pumping speed, the gas volume flow rate in the region where the electrode clamping mechanism and the pumping pipe interface are reduced, thereby mitigating the vibration enhancement caused by the high-speed airflow. This further eliminates the local gas blockage effect of the impurity gas trapped in the plasma region below the consumable electrode, improves the melting efficiency of the consumable electrode, and thus improves the preparation efficiency of rare earth-doped composite alloys.

[0038] Specifically, adjusting the vacuum pumping speed according to the decrease in the melting rate includes: The reduction in melting speed is compared with a preset reduction. If the reduction is greater than the preset reduction, it is determined that the increased vibration caused by vacuum pumping reduces the upward velocity of the impurity gas and decreases the vacuum pumping speed. The reduction is the difference between the melting rate at the beginning and the melting rate at the end of a unit monitoring cycle. The vacuum pumping speed is negatively correlated with the reduction amount.

[0039] Specifically, the reduction in melting speed is obtained by a displacement encoder 7 installed in the vacuum consumable arc furnace.

[0040] Optionally, the preset reduction range is [3.5mm / min, 10.5mm / min].

[0041] Preferably, the preferred embodiment with the preset reduction amount is 6.7 mm / min.

[0042] In practice, when the decrease in melting speed is greater than the preset decrease by less than 2 mm / min, the vacuum pumping speed is adjusted to 95% of the current vacuum pumping speed. When the decrease in melting speed exceeds the preset decrease by more than 2 mm / min, the vacuum pumping speed is reduced for every 1 mm / min exceeding 2 mm / min. In one specific embodiment, the current reduction in melting rate is 7.0 mm / min, and the current vacuum pumping rate is... The reduced vacuum pumping speed is .

[0043] Please see Figure 3 As shown, this is a flowchart illustrating the method for determining the direction of the induced magnetic field in the preparation method of the high-temperature resistant rare-earth-doped composite alloy material according to an embodiment of the present invention. The step of determining the direction of the induced magnetic field in the plasma region vertically below the consumable electrode based on the droplet's fall length includes: Obtain the fall length of several individual molten droplets within the droplet fall time interval; If the difference between the length of the first molten droplet falling at the previous moment and the length of the second molten droplet falling at the next moment in a single time point of the droplet falling time segment is greater than a second preset difference, the direction of the induced magnetic field is determined to be vertically downward. If the difference is less than the first preset difference, the direction of the induced magnetic field is determined to be vertically upward.

[0044] Specifically, the droplet falling time segment is a time window of 15 to 60 seconds, starting from the moment when the consumable electrode begins to melt.

[0045] Optionally, the first preset difference can be selected within a range of [2mm, 5mm]; the second preset difference can be selected within a range of [10mm, 15mm].

[0046] Preferably, the first preset difference is 3 mm in a preferred embodiment; the second preset difference is 12 mm in a preferred embodiment.

[0047] Specifically, the second preset difference is greater than the first preset difference.

[0048] Specifically, determining the stirring speed of the electromagnetic stirring mechanism based on the proportion of time intervals in which the directions of the induced magnetic field and the electromagnetic stirring magnetic field are opposite includes: Compare the percentage of the time segment length with the preset percentage; If the length of the time segment is greater than the preset percentage, it is determined that the influence of the induced magnetic field on the electromagnetic stirring mechanism does not meet the requirements, and the stirring speed of the electromagnetic stirring mechanism is increased.

[0049] Specifically, the stirring speed of the electromagnetic stirring mechanism is adjusted by changing the magnetic field of the magnetic field generator.

[0050] As will be understood by those skilled in the art, the operating principle and process of a magnetic field generator are conventional technical means well known to them, and therefore the operating principle and process of a magnetic field generator will not be described in detail here.

[0051] Optional, the preset percentage can be selected from [20%, 40%].

[0052] Preferably, the preset percentage in the preferred embodiment is 30%.

[0053] Specifically, the stirring speed is positively correlated with the proportion of the time interval length.

[0054] In practice, when the proportion of the time segment length is greater than the preset proportion by less than 2%, the stirring speed is adjusted to 1.1 times the current stirring speed. When the proportion of the time segment length is greater than the preset proportion by more than 2%, the stirring speed is increased by 1 rpm for every 1% exceeding 2%. In a specific embodiment, the proportion of the time segment length with the opposite trend of the current magnetic field direction change is 35%, the current stirring speed of the electromagnetic stirring mechanism is 200 rpm, and the increased stirring speed is 200 rpm × 1.1 + (3% / 1%) × 1 rpm = 223 rpm.

[0055] In practice, this invention determines the direction of the induced magnetic field in the plasma region vertically below the consumable electrode based on the droplet's fall length. When the difference between the first droplet fall length at the previous moment and the second droplet fall length at the next moment within a single time point of the droplet fall time segment is greater than a second preset difference, it indicates that the droplet can be stretched to a longer size before detaching, and the direction of the induced magnetic field is vertically downward. When this difference is less than the first preset difference, it indicates that the droplet is subjected to a stronger constraint and detaches earlier, meaning that the electromagnetic environment of the plasma region is developing in the direction of arc contraction, and the direction of the induced magnetic field is vertically upward. When the proportion of time segments with opposite magnetic field directions in the induced magnetic field and electromagnetic stirring magnetic field is greater than a preset proportion, it proves that the droplet fall length caused by impurity gas has changed compared to the normal fall length, causing the released impurity gas to form a local low conductivity region within the plasma region, hindering... Disrupting the normal current path forces the electric arc to find an alternative path, thereby altering the natural distribution of the electromagnetic field. If the electromagnetic stirring mechanism continues to stir at a fixed speed, the rotating magnetic field generated by the stirring mechanism will conflict directionally with the electromagnetic field of the disturbed plasma region, generating mutually canceling Lorentz forces, which reduces stirring efficiency. This reduction in stirring efficiency further exacerbates microsegregation, macroscopically manifested as thickening of the ingot's solidified shell and the occurrence of non-sequential solidification. By increasing the stirring speed of the electromagnetic stirring mechanism according to the increased proportion of the time interval between the induced magnetic field direction and the electromagnetic stirring magnetic field direction being opposite, the efficiency loss caused by the directional conflict between the rotating magnetic field generated by the stirring mechanism and the inherent electromagnetic field of the disturbed plasma region can be compensated. This promotes the homogenization of the temperature and concentration fields in the molten pool, thereby reducing microsegregation and restoring the normal sequential solidification process, improving the melting efficiency of the consumable electrode, and thus improving the preparation efficiency of rare earth-doped composite alloys.

[0056] Specifically, the time segment length ratio is the ratio of the length of the time segment with opposite magnetic field directions to the length of the time segment lasting for a unit magnetic field monitoring cycle, wherein, The opposite directions of the magnetic fields include: Within a unit magnetic field monitoring cycle, the induced magnetic field is vertically downward, and the electromagnetic stirring magnetic field is vertically upward. Within a unit magnetic field monitoring cycle, the induced magnetic field is vertically upward, and the electromagnetic stirring magnetic field is vertically downward.

[0057] Specifically, the unit magnetic field monitoring cycle is 10 seconds.

[0058] Please see Figure 4As shown, this is a flowchart illustrating the process of determining the height segment corresponding to impurities on the consumable electrode in the preparation method of high-temperature resistant rare-earth-doped composite alloy materials according to an embodiment of the present invention. The step of determining the height segment 9 corresponding to impurities on the consumable electrode based on the planar image includes: Compare the maximum area of ​​the molten pool in the planar image of the molten pool splash with a preset area; If the maximum area of ​​the molten pool is less than or equal to the preset area, it is determined that the degree of influence of impurities on the molten droplets does not meet the requirements. The vertical height range on the consumable electrode corresponding to the time interval in which the maximum area of ​​the molten pool is less than the preset area is determined as the height segment 9 corresponding to the impurity on the consumable electrode.

[0059] Optionally, the selectable range of the preset area is: .

[0060] Preferably, the preferred embodiment of the preset area is as follows: .

[0061] Specifically, adjusting the current of the smelting process according to the height range includes: The length of the height segment is compared with the preset length; If the length of the height segment is greater than the preset length, the current in the smelting process is reduced, wherein... The current is negatively correlated with the length of the height segment.

[0062] Specifically, the working current of the melting process is adjusted by changing the electrode spacing.

[0063] As will be understood by those skilled in the art, the operating principle and process of controlling the feed speed of the consumable electrodes by a servo motor in a vacuum consumable arc furnace to change the electrode spacing and thus adjust the working current of the melting process are conventional techniques well known to those skilled in the art. Therefore, the operating principle and process of controlling the feed speed of the consumable electrodes by a servo motor in a vacuum consumable arc furnace to change the electrode spacing and thus adjust the working current of the melting process will not be described in detail here.

[0064] Optionally, the preset length can be selected from [10mm, 20mm].

[0065] Preferably, the preset length is 15mm.

[0066] In implementation, when the length of the height section is within 2mm of the preset length, the working current of the melting process is adjusted to 95% of the current working current. When the length of the height section is more than 2mm of the preset length, the working current of the melting process is reduced by 1A for every 1mm exceeding 2mm. In a specific embodiment, the current length of the height section is 18mm, the current of the current melting process is 8000A, and the reduced current of the melting process is 8000A×95%-(1mm / 1mm)×1A=7599A.

[0067] In practice, this invention characterizes the phenomenon by indicating that, due to the vacuuming vibration, impurity gases retained in the plasma region are re-expanded and removed by vacuum. Some impurity components condense and adhere to the surface of the consumable electrode along the path of the vacuuming process. When the consumable electrode melts to the impurity attachment location, impurity-containing droplets form and fall. Because the impurity components alter the physical properties of the droplets—i.e., impurity elements act as surface-active substances and agglomerate on the droplet surface—the droplets containing impurities tend to cluster upon impact with the molten pool due to decreased surface tension and increased viscosity. This results in a concentrated spatter area, manifested in the planar image of the molten pool spatter as a small maximum area of ​​the molten pool. Therefore, when the maximum area of ​​the molten pool is detected to be smaller than the preset area, it is determined that the degree of influence of impurities due to the change in the physical properties of the molten droplets caused by impurities attached to the electrode surface does not meet the requirements. Then, based on the vertical height range on the consumable electrode corresponding to the time period when the maximum area of ​​the molten pool is smaller than the preset area, the length of the height segment corresponding to the impurities on the consumable electrode is determined, and the current of the melting process is reduced. This allows the molten droplets containing impurities to enter the molten pool in a more dispersed form, reducing the instantaneous impact on the molten pool. This sequential solidification method can push the remaining small impurities to the last solidification area of ​​the ingot, such as the top area of ​​the ingot, thereby further improving the uniformity of the ingot and the purity of the ingot material, and thus improving the preparation efficiency of rare earth-doped composite alloys.

[0068] Specifically, the composite alloy material prepared by the method of preparing high-temperature resistant rare earth-doped composite alloy material in the embodiments of the present invention comprises 50 wt% to 70 wt% of matrix elements, 5 wt% to 20 wt% of solid solution strengthening elements, 2 wt% to 12 wt% of precipitation strengthening elements, less than 1 wt% of grain boundary strengthening elements, and less than 0.1 wt% of rare earth elements.

[0069] Specifically, the matrix elements include nickel, chromium, cobalt, and iron in a mass ratio of 55:25:15:5; the solid solution strengthening elements include tungsten, molybdenum, rhenium, and tantalum in a mass ratio of 40:30:20:10; the precipitation strengthening elements include aluminum, titanium, and niobium in a mass ratio of 50:30:20; the grain boundary strengthening elements include carbon, boron, and zirconium in a mass ratio of 60:25:15; and the rare earth elements include yttrium, lanthanum, and cerium in a mass ratio of 50:30:20.

[0070] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-temperature resistant rare-earth-doped composite alloy material, characterized in that, include: The consumable electrode, which is composed of electrode ingots output from a vacuum induction melting furnace, is melted in a vacuum environment. The amount by which the melting rate of the consumable electrode decreases during the smelting process is obtained; Adjust the vacuum pumping speed according to the amount of decrease in the melting rate; Obtain the droplet length after adjusting the vacuum pumping speed; The direction of the induced magnetic field in the plasma region vertically below the consumable electrode is determined based on the droplet's fall length. The directions of the induced magnetic field and the electromagnetic stirring magnetic field of the electromagnetic stirring mechanism around the self-consuming electrode are obtained respectively within a unit magnetic field monitoring cycle. The stirring speed of the electromagnetic stirring mechanism is determined based on the proportion of time intervals in which the directions of the induced magnetic field and the electromagnetic stirring magnetic field are opposite. Obtain a planar image of the molten pool splash on the water-cooled copper crucible after adjusting the stirring speed as described; Based on the planar image, determine the height segment corresponding to the impurity on the consumable electrode; The operating current of the smelting process is adjusted according to the height range; After the melting process is completed according to the operating current, the resulting ingot is subjected to thermomechanical processing and heat treatment in sequence to form a high-temperature resistant rare earth-doped composite alloy material.

2. The method for preparing the high-temperature resistant rare-earth-doped composite alloy material according to claim 1, characterized in that, The step of adjusting the vacuum pumping speed according to the decrease in the melting rate includes: The reduction in melting speed is compared with a preset reduction. If the reduction is greater than the preset reduction, it is determined that the increased vibration caused by vacuum pumping reduces the upward velocity of the impurity gas and decreases the vacuum pumping speed. The reduction is the difference between the melting rate at the beginning and the melting rate at the end of a unit monitoring cycle. The vacuum pumping speed is negatively correlated with the reduction amount.

3. The method for preparing the high-temperature resistant rare-earth-doped composite alloy material according to claim 2, characterized in that, The determination of the direction of the induced magnetic field in the plasma region vertically below the consumable electrode based on the droplet's fall length includes: Obtain the fall length of several individual molten droplets within the droplet fall time interval; If the difference between the length of the first molten droplet falling at the previous moment and the length of the second molten droplet falling at the next moment in a single time point of the droplet falling time segment is greater than a second preset difference, the direction of the induced magnetic field is determined to be vertically downward. If the difference is less than the first preset difference, the direction of the induced magnetic field is determined to be vertically upward.

4. The method for preparing the high-temperature resistant rare-earth-doped composite alloy material according to claim 3, characterized in that, The second preset difference is greater than the first preset difference.

5. The method for preparing the high-temperature resistant rare-earth-doped composite alloy material according to claim 4, characterized in that, The step of determining the stirring speed of the electromagnetic stirring mechanism based on the proportion of time intervals in which the directions of the induced magnetic field and the electromagnetic stirring magnetic field are opposite includes: Compare the percentage of the time segment length with the preset percentage; If the length of the time segment is greater than the preset percentage, it is determined that the influence of the induced magnetic field on the electromagnetic stirring mechanism does not meet the requirements, and the stirring speed of the electromagnetic stirring mechanism is increased.

6. The method for preparing the high-temperature resistant rare-earth-doped composite alloy material according to claim 5, characterized in that, The stirring speed is positively correlated with the proportion of the time interval length.

7. The method for preparing the high-temperature resistant rare-earth-doped composite alloy material according to claim 6, characterized in that, The time segment length ratio is the ratio of the length of the time segment with opposite magnetic field directions to the length of the time segment lasting for a unit magnetic field monitoring cycle, wherein, The opposite directions of the magnetic fields include: Within a unit magnetic field monitoring cycle, the induced magnetic field is vertically downward, and the electromagnetic stirring magnetic field is vertically upward. Within a unit magnetic field monitoring cycle, the induced magnetic field is vertically upward, and the electromagnetic stirring magnetic field is vertically downward.

8. The method for preparing the high-temperature resistant rare-earth-doped composite alloy material according to claim 7, characterized in that, Determining the height segment of the impurity on the consumable electrode based on the planar image includes: Compare the maximum area of ​​the molten pool in the planar image of the molten pool splash with a preset area; If the maximum area of ​​the molten pool is less than or equal to the preset area, it is determined that the degree of influence of impurities on the molten droplets does not meet the requirements. The vertical height range on the consumable electrode corresponding to the time period when the maximum area of ​​the molten pool is less than the preset area is determined as the height range corresponding to the impurity on the consumable electrode.

9. The method for preparing the high-temperature resistant rare-earth-doped composite alloy material according to claim 8, characterized in that, The adjustment of the current in the smelting process according to the height range includes: The length of the height segment is compared with the preset length; If the length of the height segment is greater than the preset length, the current in the smelting process is reduced, wherein... The current is negatively correlated with the length of the height segment.

10. A rare earth-doped composite alloy material prepared using the preparation method of the high-temperature resistant rare earth-doped composite alloy material according to any one of claims 1 to 9, characterized in that, The components of rare earth-doped composite alloy materials include 50 wt% to 70 wt% of matrix elements, 5 wt% to 20 wt% of solid solution strengthening elements, 2 wt% to 12 wt% of precipitation strengthening elements, less than 1 wt% of grain boundary strengthening elements, and less than 0.1 wt% of rare earth elements.

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