Method for regulating and controlling Laves phase morphology in solidification process of high-temperature alloy melt and product
By adding Ce-Fe alloy and applying pulsed current during the solidification process of high-temperature alloy melt, the morphology of the Laves phase was controlled, thus solving the problem of Laves phase growth and precipitation during the solidification process of high-temperature alloy melting and achieving efficient alloy purification and performance optimization.
Patent Information
- Application Number
- CN202511474372.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-15
- Publication Date
- 2026-02-27
AI Technical Summary
Existing technologies struggle to effectively control the Laves phase morphology during the melting and solidification of high-temperature alloys, leading to severe dendrite segregation. Furthermore, traditional homogenization processes are energy-intensive, time-consuming, costly, and carry a high risk of grain coarsening.
During the solidification process of high-temperature alloy melt, by adding Ce-Fe alloy raw materials and applying pulsed current, and setting appropriate pulse voltage, current density and frequency, the morphology of the Laves phase can be controlled to form fine rod-shaped, needle-shaped and micro-granular Laves phases, thereby reducing its area ratio and average particle size.
This method enables efficient control of the Laves phase morphology, reduces homogenization heat treatment time, lowers production costs, optimizes alloy properties, and improves material yield.
Smart Images
Figure CN121575252A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of high-temperature alloy melt purification, and particularly relates to a method for regulating Laves phase morphology in the solidification process of a high-temperature alloy melt and a product. BACKGROUND
[0002] In recent years, nickel-based high-temperature alloys are widely used in the manufacture of key components (such as turbine disks and casings) of hot end parts of aero-engines and gas turbines due to their excellent high-temperature strength, creep resistance and fatigue resistance. However, due to the complex composition of high-temperature alloys, which contains a large amount of refractory elements such as Nb and Mo, there is a serious tendency of dendritic segregation in the traditional high-temperature alloy smelting and solidification process. At the end of solidification, Nb, Mo and other elements are enriched in the interdendritic region, and through eutectic reaction, coarse and continuous network or block Laves phases are generated, which are extremely harmful to the performance of the alloy. The main means to eliminate Laves phases and improve element segregation in industry is high-temperature homogenization heat treatment, that is, the ingot is subjected to heat preservation at a temperature slightly lower than the initial melting point (such as 1150℃) for tens of hours or even hundreds of hours, so as to homogenize the elements through diffusion and dissolve the Laves phases. However, this method has obvious disadvantages: first, the energy consumption is huge, the processing period is extremely long, and the production cost is high; second, long-time high-temperature heating leads to serious grain coarsening, and subsequent complex thermal mechanical processing is needed to refine the grains, increasing the process complexity; third, for large-size ingots, the core region often has residual segregation and Laves phases due to insufficient diffusion, and the homogenization effect cannot be guaranteed.
[0003] At present, there are high-temperature homogenization diffusion annealing, rapid solidification technology and adding trace alloying elements to solve the above problems, but they cannot effectively solve the problem. High-temperature homogenization annealing has huge energy consumption, high production cost and long production cycle, low efficiency, and the treated sample has the risk of grain coarsening and element oxidation and burning. The addition of alloying elements requires precise control of the amount of addition, and excessive addition will form low-melting-point eutectic phases. Therefore, developing a new method that can in-situ and efficiently control the morphology of Laves phases during solidification has great engineering value and scientific significance for reducing the production cost of high-performance high-temperature alloys and improving the material performance and yield. SUMMARY
[0004] In order to overcome the above problems in the prior art, the present application provides a method for regulating Laves phase morphology in the solidification process of a high-temperature alloy melt and a product, which is used to solve the above problems in the prior art.
[0005] A method for regulating Laves phase morphology in the solidification process of a high-temperature alloy melt, comprising the following steps: S2. The melt is kept for a certain time, and then the Ce-Fe alloy raw material wrapped with nickel foil is added, followed by stirring for a certain time; S3. In the uniformly stirred and continuously kept melt, two parallel graphite electrodes with pulse current are inserted into the melt, and preheated for a certain time; S4. According to the Ce content of the Ce-Fe alloy added in the high-temperature alloy, the pulse voltage, pulse current and pulse frequency parameters of the electric pulse to be applied are set, and the electric pulse is applied to the melt for a certain time during the furnace cooling and solidification stage after the electric resistance furnace is turned off; S5. After the treatment is completed, the pulse power connected with the electric pulse is turned off, and the obtained sample is cooled with the furnace.
[0006] According to the aspects and any possible implementation ways described above, further provided is an implementation way, wherein the temperature in S1 is 1450-1500℃, and the time is 30-60 min.
[0007] According to the aspects and any possible implementation ways described above, further provided is an implementation way, wherein the time in S2 and S3 is 5-10 min, and the time in S4 is 10-60 min.
[0008] According to the aspects and any possible implementation ways described above, further provided is an implementation way, wherein the parameters are that the pulse voltage is 10-36 V, the current density is 1-100 A / mm 2 , and the pulse frequency is 100-10000 Hz.
[0009] According to the aspects and any possible implementation ways described above, further provided is an implementation way, wherein when the Ce content of the Ce-Fe alloy added in the high-temperature alloy is [0.01, 0.05]wt.%, the pulse voltage is [10, 20]V, the current density is [1, 10]A / mm 2 , and the pulse frequency is [100, 300]Hz; When the Ce content of the Ce-Fe alloy added in the high-temperature alloy is (0.05, 0.1]wt.%, the pulse voltage is (20, 30]V, the current density is (10, 40]A / mm 2 , and the pulse frequency is (300, 1000]Hz; When the Ce content of the Ce-Fe alloy added in the high-temperature alloy is (0.1, 0.2]wt.%, the pulse voltage is (30, 36]V, the current density is (40, 100]A / mm 2 , and the pulse frequency is (1000, 10000]Hz.
[0010] In the aspect and any possible implementation manner as described above, further provided is an implementation manner, in the step S3, the electrode bottom reaches the bottom of the molten pool where the melt is located until the insertion depth, and the material of the electrode is graphite.
[0011] In the aspect and any possible implementation manner as described above, further provided is an implementation manner, the raw material is 718Plus nickel-based superalloy.
[0012] In the aspect and any possible implementation manner as described above, further provided is an implementation manner, in the step S1, the smelting temperature of the superalloy raw material is 1450-1550℃.
[0013] In the aspect and any possible implementation manner as described above, further provided is an implementation manner, in the step S2, the smelting temperature of the Ce-Fe alloy raw material is 1400-1500℃.
[0014] The application further provides a superalloy prepared by the method, and the as-cast alloy has a smaller Laves phase area ratio and average particle size.
[0015] Advantages of the application The application utilizes the method for regulating the Laves phase morphology in the solidification process of the superalloy melt by means of the pulse current and rare earth Ce, sets the corresponding initial pulse voltage, pulse current and pulse frequency according to the Ce content of the Ce-Fe alloy added in the superalloy, and thus the Laves phase morphology can be regulated and the superalloy melt can be purified in the smelting and solidification process of the superalloy. The method can effectively solve the growth and precipitation of the Laves phase in the smelting and solidification process of the superalloy, greatly reduces the time required for the homogenization heat treatment of the alloy, and greatly reduces the production cost. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 The application provides the Laves phase size and morphology of the superalloy solidified without the rare earth Ce and the pulse current treatment in the examples and the comparative examples, wherein (a) is an effect diagram of the examples, and (b) is an effect diagram of the comparative examples.
[0017] Figure 2 The application provides a flow chart of the method. DETAILED DESCRIPTION
[0018] In order to better understand the technical scheme of the application, the content of the application includes but is not limited to the specific embodiments in the following description, and similar technologies and methods should be regarded as falling within the protection scope of the application. In order to make the technical problems, technical scheme and advantages of the application more clear, the following will be described in detail in combination with the drawings and specific embodiments.
[0019] It should be understood that the embodiments described herein merely exemplify some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.
[0020] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.
[0021] In view of the problem of a large amount of Laves phase precipitated in the melting and solidification process of a nickel-based superalloy, the existing technical means such as high-temperature homogenization diffusion annealing, rapid solidification technology and adding trace alloying elements are limited by their cost and efficiency, and are hindered in industrial production. The present application proposes a method for regulating the morphology of Laves phase in the solidification process of superalloy melt by using pulse current in cooperation with rare earth Ce.
[0022] According to one aspect of the present application, the present application provides the following technical scheme: A method for regulating the morphology of Laves phase in the solidification process of superalloy melt by using pulse current in cooperation with rare earth Ce, comprising the following steps: S1: placing the superalloy raw material in a crucible and heating it to 1450-1500°C in an electric resistance furnace, and keeping it for 30-60 min to fully melt the raw material; S2: continue to keep the melt, add the Ce-Fe alloy raw material wrapped in nickel foil, and then stir the melt for 5-10 min to make its composition and temperature uniform; S3: continue to keep the melt, and vertically insert two parallel graphite electrodes into the melt through metal wires connected with a pulse power supply, and preheat for 5-10 min; S4: according to the Ce content of the Ce-Fe alloy added in the superalloy, set the initial pulse voltage, pulse current and pulse frequency, close the electric resistance furnace, and apply an electric pulse treatment to the melt for 10-60 min when the Laves phase is precipitated during the cooling and solidification stage in the furnace, so that the island-shaped, block-shaped and strip-shaped Laves phase is deformed into fine rod-shaped, needle-shaped and small particle-shaped Laves phase, reducing the area ratio of Laves phase in the as-cast alloy and the average particle size of Laves phase, thereby realizing the purification of the superalloy melt; S5: turn off the pulse power supply after the treatment is completed, and cool the sample with the furnace.
[0023] Preferably, in the step S1, the melting temperature of the superalloy raw material is controlled within a temperature range in which the superalloy raw material is completely in a molten state and meets the industrial production, specifically 1450-1550℃.
[0024] Preferably, in the step S2, the melting temperature of the Ce-Fe alloy raw material is controlled within a temperature range in which the Ce-Fe alloy raw material is completely in a molten state and meets the industrial production, specifically 1400-1500℃.
[0025] Preferably, in the step S3, the electrode bottom reaches the bottom of the molten pool to a depth of insertion, and the material is graphite, thereby constructing a stable high-density pulse current throughout the molten body, so as to excite the electromagnetic stirring effect and the electromigration effect, and realize all-around optimization from the molten state to the final solidification structure.
[0026] Preferably, in the step S4, the pulse voltage is 10-36V, the current density is 1-100A / mm 2 , and the pulse frequency is 100-10000Hz.
[0027] Further preferably, in the step S4, the initial pulse voltage, pulse current and pulse frequency are set according to the Ce content of the Ce-Fe alloy added in the superalloy, specifically: when the Ce content of the Ce-Fe alloy added in the superalloy is 0.01-0.05wt.%, the pulse voltage is 10-20V, the current density is 1-10A / mm 2 , the pulse frequency is 100-300Hz, the Laves phase area ratio is reduced by 30%-35%, and the average particle size is reduced by 60%-70%; when the Ce content of the Ce-Fe alloy added in the superalloy is 0.05-0.1wt.%, the pulse voltage is 20-30V, the current density is 10-40A / mm 2 , the pulse frequency is 300-1000Hz, the Laves phase area ratio is reduced by 35%-40%, and the average particle size is reduced by 70%-80%; when the Ce content of the Ce-Fe alloy added in the superalloy is 0.1-0.2wt.%, the pulse voltage is 30-36V, the current density is 40-100A / mm 2 , the pulse frequency is 1000-10000Hz, the Laves phase area ratio is reduced by 40%-45%, and the average particle size is reduced by 80%-90%.
[0028] The technical scheme of the present application is further described below in combination with specific embodiments.
[0029] Embodiment 1 The embodiment melts 718Plus nickel-based superalloy raw material, adds Ce-Fe alloy, and then performs pulse current treatment, and the rare earth content of the product is 200 ppm. The steps include: S1: Place the superalloy raw material in the crucible and heat it to 1500°C in the resistance furnace, and keep it for 30 min to fully melt the raw material; S2: Continue to keep the melt, add the Ce-Fe alloy raw material wrapped in nickel foil, and then stir the melt for 5 min to make its composition and temperature uniform; S3: Continue to keep the melt, and vertically insert two parallel graphite electrodes into the melt through metal wires connected to the pulse power supply, and preheat for 5 min; S4: According to the Ce content of the Ce-Fe alloy added in the superalloy, set the initial pulse voltage, pulse current and pulse frequency: the pulse voltage is 20 V, the current density is 4.8 A / mm 2 , the pulse frequency is 300 Hz, and the melt is subjected to 20 min of electric pulse treatment during the holding stage; S5: After the treatment is completed, turn off the resistance furnace and the pulse power supply, and cool the sample with the furnace.
[0030] S6: The solidified ingot obtained after pulse treatment is longitudinally cut along the center line of the two electrodes, and after polishing, the overall distribution of Laves phase can be clearly observed in the backscattering mode of the scanning electron microscope. It is observed that the Laves phase is uniformly distributed in the ingot and no enrichment phenomenon occurs. After detecting and statistically analyzing the Laves phase in different positions, the area ratio of the Laves phase is reduced from the original 3.09% (the ingot obtained when the 718Plus nickel-based superalloy raw material is melted and no Ce-Fe alloy is added as the original comparative example) to 2.06%, with a maximum reduction rate of 33.3%. The average grain size of the Laves phase is reduced from the original 100.08 μm to a minimum of 33.78 μm, with a maximum reduction rate of 66.2%. The dislocation pinning is strengthened, the stress distribution is optimized, and the superalloy ingot is purified.
[0031] Example 2 The embodiment melts 718Plus nickel-based superalloy raw material, adds Ce-Fe alloy, and then performs pulse current treatment, and the rare earth content of the product is 800 ppm. The steps include: S1: Place the superalloy raw material in the crucible and heat it to 1500°C in the resistance furnace, and keep it for 30 min to fully melt the raw material; S2: Continue to keep the melt, add the Ce-Fe alloy raw material wrapped in nickel foil, and then stir the melt for 5 min to make its composition and temperature uniform; S3: The melt continues to be kept warm, two parallel graphite electrodes are vertically inserted into the melt after being connected with the pulse power through metal wires, and preheated for 5 min; S4: According to the Ce content of the Ce-Fe alloy added in the high-temperature alloy, the initial pulse voltage, pulse current and pulse frequency are set: the pulse voltage is 30 V, the current density is 25.7 A / mm 2 , the pulse frequency is 1000 Hz, and the melt is subjected to 20 min of electric pulse treatment in the holding stage; S5: After the treatment is completed, the resistance furnace is turned off, the pulse power is turned off, and the sample is cooled with the furnace.
[0032] S6: The solidified ingot obtained after pulse treatment is longitudinally cut along the center line of the two electrodes, and after polishing, the overall distribution of the Laves phase can be clearly observed in the backscattering mode of the scanning electron microscope. It is observed that the Laves phase is uniformly distributed in the ingot and no enrichment phenomenon occurs. After detecting and statistically analyzing the Laves phase at different positions, the area ratio of the Laves phase is reduced from the original 3.09% to 1.94%, with a maximum reduction rate of 37.2%. The average grain size of the Laves phase is reduced from the original 100.08 μm to the minimum of 20.24 μm, with a maximum reduction rate of 79.8%. The dislocation pinning is strengthened, the stress distribution is optimized, and the high-temperature alloy ingot is purified.
[0033] Example 3 In this example, the 718Plus nickel-based high-temperature alloy raw material is melted, and the Ce-Fe alloy is added for pulse current treatment, and the rare earth content of the product is 2000 ppm. It includes the following steps: S1: The high-temperature alloy raw material is placed in the crucible and heated to 1500°C in the resistance furnace, and kept warm for 30 min to fully melt the raw material; S2: The melt continues to be kept warm, and the Ce-Fe alloy raw material wrapped in nickel foil is added, and then the melt is stirred for 5 min to make the composition and temperature uniform; S3: The melt continues to be kept warm, two parallel graphite electrodes are vertically inserted into the melt after being connected with the pulse power through metal wires, and preheated for 5 min; S4: According to the Ce content of the Ce-Fe alloy added in the high-temperature alloy, the initial pulse voltage, pulse current and pulse frequency are set: the pulse voltage is 36 V, the current density is 54.3 A / mm 2 , the pulse frequency is 3000 Hz, and the melt is subjected to 20 min of electric pulse treatment in the holding stage; S5: After the treatment is completed, the resistance furnace is turned off, the pulse power is turned off, and the sample is cooled with the furnace.
[0034] S6: The solidified ingot obtained after pulse treatment is cut along the center line of the two electrodes in the longitudinal direction, and after polishing, the overall distribution of the Laves phase can be clearly observed under the backscattering mode of the scanning electron microscope. It is observed that the Laves phase is uniformly distributed in the ingot and no enrichment phenomenon occurs. After statistical analysis of the Laves phase at different positions, the area ratio of the Laves phase is reduced from the original 3.09% to 1.81%, with a maximum reduction rate of 41.4%. The average particle size of the Laves phase is reduced from the original 100.08 μm to the minimum 15.98 μm, with a maximum reduction rate of 84%. The dislocations are pinned and the stress distribution is optimized, and the superalloy ingot is purified.
[0035] Comparative Example 1 In this comparative example, the 718Plus nickel-based superalloy raw material is melted without adding Ce-Fe alloy, and no pulse current is applied. The rare earth content of the product is 0 ppm. The steps include: S1: The superalloy raw material is placed in a crucible and heated to 1500°C in a resistance furnace, and the raw material is fully melted after holding for 30 min; S2: The melt continues to be held, and then the melt is stirred for 5 min to make the composition and temperature uniform; S3: The melt continues to be held, and two parallel graphite electrodes are vertically inserted into the melt after being connected to the pulse power source through metal wires, and are preheated for 5 min, but no pulse current is applied; S4: After the treatment is completed, the resistance furnace is turned off, the pulse power source is turned off, and the sample is cooled with the furnace.
[0036] S5: In this comparative example, the 718Plus nickel-based superalloy raw material is melted without adding Ce-Fe alloy, and no pulse current is applied. The solidified ingot obtained after treatment is cut along the center line of the two electrodes in the longitudinal direction, and after polishing, the overall distribution of the Laves phase can be clearly observed under the backscattering mode of the scanning electron microscope. It is observed that the Laves phase is uniformly distributed in the ingot and no enrichment phenomenon occurs. After statistical analysis of the Laves phase at different positions, the original area ratio of the Laves phase is 3.09%, and the original average particle size of the Laves phase is 100.08 μm. The superalloy ingot is not purified.
[0037] Comparative Example 2 In this comparative example, the 718Plus nickel-based superalloy raw material is melted after adding Ce-Fe alloy, and no pulse current is applied. The rare earth content of the product is 2000 ppm. The steps include: S1: The superalloy raw material is placed in a crucible and heated to 1500°C in a resistance furnace, and the raw material is fully melted after holding for 30 min; S2: The melt continues to be kept warm, and the Ce-Fe alloy raw material wrapped with a nickel foil is added, and then the melt is stirred for 5 min to make the composition and temperature uniform; S3: The melt continues to be kept warm, and two parallel graphite electrodes are vertically inserted into the melt after being connected to the pulse power source through metal wires and preheated for 5 min, but no pulse current treatment is applied; S4: After the treatment is completed, the resistance furnace is turned off, the pulse power source is turned off, and the sample is cooled with the furnace.
[0038] S5: In this comparative example, no pulse current is applied, and after the treatment, the solidified ingot is cut along the center line of the two electrodes in the longitudinal direction, polished, and then the overall distribution of the Laves phase can be clearly observed in the backscattering mode of the scanning electron microscope. It is observed that the Laves phase is uniformly distributed in the ingot and no enrichment phenomenon occurs. After detecting and statistically analyzing the Laves phase at different positions, the area ratio of the Laves phase is reduced from the original 3.09% to 2.98%, with a maximum reduction rate of 3.6%, the average particle size of the Laves phase is reduced from the original 100.08 μm to the minimum of 87.66 μm, with a maximum reduction rate of 12.4%, and the superalloy ingot cannot be purified.
[0039] Comparative Example 3 In this comparative example, the 718Plus nickel-based superalloy raw material is melted without adding the Ce-Fe alloy for pulse current treatment, and the product has a rare earth content of 0 ppm. The following steps are included: S1: The superalloy raw material is placed in a crucible and heated to 1500°C in a resistance furnace, and kept warm for 30 min to fully melt the raw material; S2: The melt continues to be kept warm, and then the melt is stirred for 5 min to make the composition and temperature uniform; S3: The melt continues to be kept warm, and two parallel graphite electrodes are vertically inserted into the melt after being connected to the pulse power source through metal wires and preheated for 5 min; S4: The initial pulse voltage, pulse current, and pulse frequency are set: the pulse voltage is 36 V, the current density is 25.7 A / mm 2 , the pulse frequency is 1000 Hz, and the melt is subjected to 20 min of pulse current treatment during the holding stage; S5: After the treatment is completed, the resistance furnace is turned off, the pulse power source is turned off, and the sample is cooled with the furnace.
[0040] S6: The S6 example does not add Ce-Fe alloy for smelting, and the solidified ingot obtained after pulse treatment is longitudinally cut along the center line of the two electrodes. After polishing, the overall distribution of Laves phase can be clearly observed under the backscattering mode of the scanning electron microscope. It is observed that the Laves phase is uniformly distributed in the ingot and no enrichment phenomenon occurs. After statistical analysis of the Laves phase in different positions, the area ratio of the Laves phase is reduced from the original 3.09% to 2.71% at the lowest, with a maximum reduction rate of 12.3%. The average grain size of the Laves phase is reduced from the original 100.08 μm to 71.23 μm at the lowest, with a maximum reduction rate of 28.8%. The high-temperature alloy ingot fails to achieve purification.
[0041] Comparative Example 4 The S6 example does not add Ce-Fe alloy for smelting, and the solidified ingot obtained after pulse treatment is longitudinally cut along the center line of the two electrodes. After polishing, the overall distribution of Laves phase can be clearly observed under the backscattering mode of the scanning electron microscope. It is observed that the Laves phase is uniformly distributed in the ingot and no enrichment phenomenon occurs. After statistical analysis of the Laves phase in different positions, the area ratio of the Laves phase is reduced from the original 3.09% to 2.71% at the lowest, with a maximum reduction rate of 12.3%. The average grain size of the Laves phase is reduced from the original 100.08 μm to 71.23 μm at the lowest, with a maximum reduction rate of 28.8%. The high-temperature alloy ingot fails to achieve purification. S1: The high-temperature alloy raw material is placed in the crucible and heated to 1500°C in the resistance furnace for 30 min to fully melt the raw material; S2: Continue to heat the melt, add Ce-Fe alloy raw material wrapped in nickel foil, and then stir the melt for 5 min to make the composition and temperature uniform; S3: Continue to heat the melt, and then vertically insert two parallel graphite electrodes into the melt through metal wires connected to the pulse power source, and preheat for 5 min; S4: According to the Ce content of the Ce-Fe alloy added in the high-temperature alloy, the initial pulse voltage, pulse current and pulse frequency are set: the pulse voltage is 36 V, the current density is 4.8 A / mm 2 , the pulse frequency is 1000 Hz, and the melt is subjected to 20 min of electric pulse treatment during the holding stage; S5: After the treatment is completed, the resistance furnace is turned off, the pulse power source is turned off, and the sample is cooled in the furnace.
[0042] S6: The S6 example does not add Ce-Fe alloy for smelting, and the solidified ingot obtained after pulse treatment is longitudinally cut along the center line of the two electrodes. After polishing, the overall distribution of Laves phase can be clearly observed under the backscattering mode of the scanning electron microscope. It is observed that the Laves phase is uniformly distributed in the ingot and no enrichment phenomenon occurs. After statistical analysis of the Laves phase in different positions, the area ratio of the Laves phase is reduced from the original 3.09% to 2.71% at the lowest, with a maximum reduction rate of 12.3%. The average grain size of the Laves phase is reduced from the original 100.08 μm to 71.23 μm at the lowest, with a maximum reduction rate of 28.8%. The high-temperature alloy ingot fails to achieve purification.
[0043] From the above examples and comparative examples, it can be seen that the present application needs to be in a complete molten state and in the temperature range of industrial production of the high-temperature alloy raw material and in a complete molten state and in the temperature range of industrial production of the Ce-Fe alloy raw material, and according to the different Ce content of the Ce-Fe alloy added in the high-temperature alloy, the corresponding initial pulse voltage, pulse current and pulse frequency are set, so that the morphology of the Laves phase can be controlled and the high-temperature alloy melt can be purified during the smelting and solidification process of the high-temperature alloy. The method of the present application can effectively solve the growth and precipitation of the Laves phase during the smelting and solidification process of the high-temperature alloy, greatly reduce the time required for the homogenization heat treatment of the alloy, and greatly reduce the production cost.
[0044] As an embodiment disclosed by the present application, the present application further provides a high-temperature alloy, which is prepared by the method to obtain a cast alloy with a smaller Laves phase area ratio and average particle size, which is beneficial to greatly reduce the time of eliminating the Laves phase in the subsequent homogenization process.
[0045] The above description shows and describes several preferred embodiments of the present application, but as previously described, it should be understood that the present application is not limited to the forms disclosed herein, should not be considered as excluding other embodiments, and can be used in various other combinations, modifications and environments, and can be modified within the scope of the application described herein by the above teaching or related technical or knowledge. The modifications and changes made by those skilled in the art without departing from the spirit and scope of the present application shall be within the protection scope of the claims of the present application.
Claims
1. A method for controlling the morphology of the Laves phase during the solidification process of a high-temperature alloy melt, characterized in that, Includes the following steps: S1. Place the high-temperature alloy raw material in a crucible and heat it to a certain temperature in a resistance furnace. Hold the temperature for a period of time to allow the raw material to melt completely and obtain a melt. S2. Continue to keep the melt at a constant temperature, add the Ce-Fe alloy raw material wrapped in nickel foil, and then stir for a period of time; S3. In the melt that is being stirred and kept at a constant temperature, insert two parallel graphite electrodes carrying a pulsed current into the melt and preheat it for a period of time. S4. Based on the Ce content of the Ce-Fe alloy added to the high-temperature alloy, set the pulse voltage, pulse current and pulse frequency parameters of the electric pulse to be applied, and apply the electric pulse to the melt for a period of time during the cooling and solidification stage in the furnace after the resistance furnace is shut down. S5. After the treatment is completed, turn off the pulse power supply connected to the electrical pulse and cool the obtained sample with the furnace.
2. The method according to claim 1, characterized in that, The temperature in S1 is 1450~1550℃, and the time period is 30~60min.
3. The method according to claim 1 or 2, characterized in that, The time intervals in S2 and S3 are 5-10 minutes, and the time interval in S4 is 10-60 minutes.
4. The method according to claim 1 or 2, characterized in that, The parameters are: pulse voltage of 10~36V and current density of 1~100A / mm². 2 The pulse frequency is 100~10000Hz.
5. The method according to claim 4, characterized in that, When the Ce content of the Ce-Fe alloy added to the high-temperature alloy is [0.01, 0.05] wt.%, the pulse voltage is [10, 20] V, and the current density is [1, 10] A / mm. 2 The pulse frequency is [100, 300] Hz; When the Ce content in the Ce-Fe alloy added to the high-temperature alloy is (0.05, 0.1] wt.%, the pulse voltage is (20, 30] V, and the current density is (10, 40 A] / mm. 2 The pulse frequency is (300, 1000] Hz; When the Ce content in the Ce-Fe alloy added to the high-temperature alloy is (0.1, 0.2] wt.%, the pulse voltage is (30, 36] V, and the current density is (40, 100] A / mm. 2 The pulse frequency is (1000, 10000] Hz.
6. The method according to claim 1, characterized in that, In step S3, the bottom of the electrode is inserted to the bottom of the molten pool where the melt is located, and the electrode is made of graphite.
7. The method according to claim 1 or 2, characterized in that, The raw material is 718Plus nickel-based high-temperature alloy.
8. The method according to claim 1 or 2, characterized in that, In step S1, the melting temperature of the high-temperature alloy raw material is 1450~1550℃.
9. The method according to claim 1 or 2, characterized in that, In step S2, the melting temperature of the Ce-Fe alloy raw material is 1400~1500℃.
10. A high-temperature alloy, characterized in that, The high-temperature alloy is prepared by the method described in any one of claims 1-9 to obtain a cast alloy with a smaller Laves phase area ratio and average grain size.