Method for designing metal melt structure and microscopic solidification structure

Abstract

The invention relates to the technical field of melt structure regulation and control, in particular to a method for designing a metal melt structure and a microcosmic solidification structure, which comprises the following steps: placing a metal sample in a high-intensity magnetic field material treatment device, and applying a target high-intensity magnetic field; carrying out multiple times of melt superheating and supercooling treatment, recording an m0-T-t curve of the last heating and cooling stage of the sample, and obtaining theta and C of the melt according to the m0-T-t curve; judging the structure of the melt according to the obtained theta and C values, and when the melt is in a target structure, recording the process path of the heating stage of the overheating and supercooling treatment; a to-be-treated metal sample is heated through a process path, a target structure melt can be obtained, and a target microcosmic solidification structure can be obtained after cooling. According to the method provided by the invention, the melt state is indirectly observed by a method for quantifying melt structure parameters, and an expected melt structure is obtained by controlling a series of melt processing parameters, so that similar microstructures and performances under various path technologies are obtained.

Description

Technical Field

[0001] This invention belongs to the field of melt structure control technology, specifically relating to a method for designing the structure and microstructure of metal melts. Background Technology

[0002] During the forming process, metals and their products undergo at least one solidification process, transforming from a liquid phase to a solid phase. Above the melting point, the metal is in a molten state, with a microscopically inhomogeneous structure containing numerous clusters, which significantly influence the cooling solidification structure and properties. With increasing temperature, the melt structure transforms from high-density, large-sized clusters to finer, more dispersed clusters, corresponding to low-temperature L1 melts and high-temperature L2 melts. L2 melt clusters have a higher critical nucleation work during cooling, require a larger nucleation undercooling, and have a shorter solidification time, readily forming uniform and fine equiaxed crystals, significantly improving the alloy's mechanical strength. Therefore, obtaining L2 melts through process parameter optimization is of significant value in industry.

[0003] Current research on melt structure control mainly focuses on obtaining L2 melts by increasing the superheat temperature (approximately 300°C above the melting point) and holding it at that temperature for an extended period. However, in industrial production, increasing the superheat temperature means continuously supplying high current and voltage to the heating coils, significantly increasing equipment energy consumption. Prolonged holding also increases production costs and operational risks, and components are prone to premature failure under high-temperature, long-term holding conditions, making the development of melt structure control technology difficult. There is an urgent need to propose a new melt structure control technology that reduces costs, improves processing efficiency, and simultaneously ensures optimal processing results. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for designing the structure and microstructure of a metal melt. The method involves placing a metal sample in a specific strong magnetic field environment, using a superheating and supercooling cycle treatment method, controlling the heating and cooling rates, heating temperature, and holding time to obtain different melt states, and verifying the results using the magnetization intensity data of the melt under a strong magnetic field. Finally, the melt is cooled and solidified to form a specific microstructure.

[0005] Specifically, the present invention provides a method for designing the structure and microstructure of a molten metal, comprising the following steps: Step 1: Place the metal sample in a strong magnetic field material processing device and apply the target strong magnetic field; Step 2: Perform multiple melt overheating and undercooling treatments until the collected temperature T and the mass of the solidified sample under the magnetic field do not fluctuate significantly with time t. Record the m0-Tt curve of the sample during the last heating and cooling stage. Based on the m0-Tt curve, obtain the paramagnetic-ferromagnetic Curie transition temperature θ and Curie constant C of the melt. Step 3: Determine the melt structure using the θ and C values ​​obtained in Step 2. When the melt is in the target structure, record the process path of the heating stage of this overheating and overcooling treatment. Step 4: Heat the metal sample to be processed using the process path described above to obtain the target structure melt, and then cool it to obtain the target microstructure.

[0006] As a further explanation of the present invention, the method further includes: Repeat steps 2-3 multiple times, changing only the process path of the heating stage during the melt overheating and overcooling treatment each time, thus obtaining different process paths; Calculate the overall cost under different process paths, and select the optimal process path based on the overall cost; wherein, the overall cost represents the economic cost required to adopt the process path.

[0007] As a further explanation of the present invention, the overall cost includes the electricity cost caused by the increase in temperature, the loss cost introduced by the increase in temperature and time, and the labor cost introduced by the increase in time.

[0008] As a further explanation of the present invention, the formula for calculating the overall cost is as follows: (5); Where i and j represent the number of temperature increases and the number of holding periods during the heating stage, respectively. t hi Let t be the time for the i-th heating cycle. sj Let k be the heat preservation time for the j-th time. h c is the cost factor for heating element losses per unit heating time. e For electricity price, P h P is the furnace power during the heating stage. s k is the furnace power during the heat preservation stage. m c is the material failure cost coefficient per unit insulation time. l This refers to the cost of human resources per unit of time.

[0009] As a further explanation of the present invention, the process path includes the number of heating and holding times of the sample in the heating stage, the heating rate and the starting temperature of each heating, and the holding temperature and time of each holding.

[0010] As a further explanation of the present invention, before performing step 1, the process includes: heating to the maximum heating temperature at a certain rate, holding the temperature for a certain time to make the melt sufficiently uniform, and then cooling down at the same rate, repeating the above heating and cooling process until the supercooling ΔT obtained by continuous multiple measurements is stable.

[0011] As a further illustration of the present invention, a balance system配套 with the strong magnetic field material processing device is used to record the m0-T-t curve of the last heating and cooling stages of the sample.

[0012] As a further illustration of the present invention, the calculation process of the paramagnetic-ferromagnetic Curie transition temperature θ and the Curie constant C is as follows: Using the principle of Faraday balance, m0 is converted into the magnetic susceptibility χ of the sample, and its specific calculation formula is as follows: (1) where g is the gravity of the sample when solidified in the magnetic field, m is the mass of the sample without magnetic field, dH / dZ is the gradient magnetic field value at the corresponding position of the sample in the strong magnetic field material processing device, and H is the applied target magnetic field intensity; Taking the temperature T as the abscissa and the reciprocal 1 / χ of the magnetic susceptibility as the ordinate, a curve graph is plotted, and 1 / χ and T satisfy the Curie-Weiss relationship as follows: (2) Performing a linear fit on the plotted curve, the curve slope k = 1 / C, and the intercept b with the temperature axis = -θ / C. Then C and θ are calculated using the following formulas: , (3).

[0013] As a further illustration of the present invention, when judging the melt structure in step 3, when the metal sample is a Co-B alloy, the specific criterion is: When the values of C and θ simultaneously satisfy the following formula (4), the melt is in the L2 structure state; 7.45 ≤ C ≤ 8.05 1090 ≤ θ ≤ 1140 (4).

[0014] As a further illustration of the present invention, when placing the metal sample in step 1, the sample is in an environment with a specific strong magnetic field intensity H and a gradient magnetic field dH / dZ, and the direction of the gradient magnetic field is the same as the direction of gravity.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: Because the melt is under high-temperature conditions, directly observing the melt state is extremely difficult. Therefore, the influence of controlling the melt state to alter the microstructure and properties of alloys and metals is often overlooked by researchers. The method provided in this invention indirectly observes the melt state by quantifying melt structure parameters. By controlling a series of melt processing parameters such as temperature and time, the desired melt structure is obtained, thus achieving similar microstructures and properties under various processing pathways. This avoids the high power consumption and cost of single high-temperature, long-term holding methods, optimizes the melt structure processing technology, provides more processing pathways, reduces melt processing costs, and the melt composition is not limited to ferromagnetic materials such as Co, covering a wider range. It can also be used for weakly magnetic materials, thus extending to various material systems. This method is simple to operate, enabling the active design and control of melt structure, and providing more intuitive and scientific guidance for solidification microstructure and property design. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the present technical solution and form part of the specification. They are used together with the embodiments of the present technical solution to explain the present technical solution, but do not constitute a limitation thereof. In the accompanying drawings: Figure 1 It is a flowchart for designing melt structure and solidification organization.

[0017] Figure 2 (a) is Co in Embodiment 1 of the present invention. 83 B 17 Melt treatment time t, temperature T, and magnetization M curves. Figure 2 (b) is a graph showing the temperature T and the reciprocal of magnetic susceptibility 1 / χ after deformation.

[0018] Figure 3 (a) is the Co designed and prepared in Example 1 of this invention. 83 B 17 Melt type, Figure 3 (b) is a diagram of the microstructure of solidification.

[0019] Figure 4 (a) is Co in Embodiment 2 of the present invention. 81.5 B 18.5 Melt treatment time t, temperature T, and magnetization M curves. Figure 4 (b) is a graph showing the temperature T and the reciprocal of magnetic susceptibility 1 / χ after deformation.

[0020] Figure 5 (a) is the Co designed and prepared in Example 2 of this invention. 81.5 B 18.5 Melt type, Figure 5 (b) is a diagram of the microstructure of solidification.

[0021] Figure 6(a) is Co in Embodiment 3 of the present invention. 83 B 17 Melt treatment time t, temperature T, and magnetization M curves. Figure 6 (b) is a graph showing the temperature T and the reciprocal of magnetic susceptibility 1 / χ after deformation.

[0022] Figure 7 (a) is the Co designed and prepared in Example 3 of this invention. 83 B 17 Melt type, Figure 7 (b) is a diagram of the microstructure of solidification.

[0023] Figure 8 (a) is Co in Embodiment 4 of the present invention. 83 B 17 Melt treatment time t, temperature T, and magnetization M curves. Figure 8 (b) is a graph showing the temperature T and the reciprocal of magnetic susceptibility 1 / χ after deformation.

[0024] Figure 9 (a) is the Co designed and prepared in Example 4 of this invention. 83 B 17 Melt type, Figure 9 (b) is a diagram of the microstructure of solidification.

[0025] Figure 10 This is a bar chart showing the overall cost estimate of the melt designed according to Examples 1 to 4 of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention proposes a method for designing the structure and microstructure of molten metal. A strong magnetic field is generated using a liquid helium-free superconducting magnet system, aligning the metal and alloy material samples with a specific gradient magnetic field. A superheating and supercooling cycle is employed, controlling the heating and cooling rates, heating temperature, and holding time to obtain different melt states. The results are verified using magnetization data of the melt under a strong magnetic field. Finally, the melt is cooled and solidified to form a specific microstructure.

[0028] Specifically, embodiments of the present invention provide a method for designing the structure and microstructure of a molten metal, comprising the following steps: Step 1: Place the metal sample in a strong magnetic field material processing device and apply the target strong magnetic field.

[0029] Specifically, when placing the metal sample in Step 1 above, the sample is placed in an environment with a specific strong magnetic field intensity H and a gradient magnetic field dH / dZ, and the direction of the gradient magnetic field is the same as the direction of gravity.

[0030] Specifically, before performing Step 1, it further includes: heating to the highest heating temperature at a certain rate, holding for a certain time to make the melt fully uniform, and then cooling at the same rate. Repeat the above heating and cooling processes until the supercooling degree ΔT obtained from continuous multiple measurements is stable. More specifically, it is required that the supercooling degree ΔT obtained from at least continuous 5 or more measurements is stable.

[0031] Step 2: Perform multiple melt superheating and supercooling treatments until the data of the collected temperature T and the mass of the sample in the solidified state under the magnetic field versus time t do not show significant fluctuations. Record the m0-T-t curve of the last heating and cooling stages of the sample, and obtain the paramagnetic-ferromagnetic Curie transition temperature θ and Curie constant C of the melt according to the m0-T-t curve.

[0032] Specifically, use a balance system配套 with the strong magnetic field material processing device to record the m0-T-t curve of the last heating and cooling stages of the sample.

[0033] Specifically, the calculation process of the paramagnetic-ferromagnetic Curie transition temperature θ and Curie constant C is as follows: Using the Faraday balance principle, convert m0 into the magnetic susceptibility χ of the sample, and its specific calculation formula is as follows: (1) where g is the gravity of the sample during solidification under the magnetic field, m0 is the balance reading of the sample during solidification under the magnetic field, that is, the mass of the sample in the solidified state under the magnetic field, m is the balance reading without the magnetic field, that is, the mass of the sample without the magnetic field, dH / dZ is the gradient magnetic field value at the corresponding position of the sample in the strong magnetic field material processing device, and H is the applied target magnetic field intensity.

[0034] Taking the temperature T as the abscissa and the reciprocal 1 / χ of the magnetic susceptibility as the ordinate, draw a curve graph, and 1 / χ and T satisfy the Curie-Weiss relationship as follows: (2) Perform linear fitting on the drawn curve, then the curve slope k = 1 / C, and the intercept b with the temperature axis = -θ / C. Then C and θ are calculated using the following formulas: , (3).

[0035] Step 3: Judge the melt structure based on the θ and C values obtained in Step 2. When the melt is in the target structure, record the process path of the heating stage of this superheating and supercooling treatment.

[0036] Specifically, in step 3, when determining the melt structure, if the metal sample is a Co-B alloy, the specific criterion is as follows: Taking the L2 structure at high temperature as an example, when the values ​​of C and θ simultaneously satisfy the following formula (4), the melt is in the L2 structure state, while when C and θ are not in this range, it indicates that the melt is in other structure states.

[0037] 7.45≤C≤8.05 (Unit: K×m) 3 / kg) 1090≤θ≤1140 (unit: K) (4).

[0038] Specifically, the process route includes the number of heating and holding times of the sample during the heating stage, the heating rate and starting temperature of each heating, and the holding temperature and time of each holding.

[0039] Step 4: Heat the metal sample to be treated using the process path to obtain the target structure melt, and then cool it to obtain the target microstructure.

[0040] Furthermore, the method also includes: Step 5: Repeat steps 2-3 multiple times, changing only the process path of the heating stage during the melt overheating and overcooling treatment each time, thus obtaining different process paths.

[0041] Step 6: Calculate the overall cost under different process paths, and select the optimal process path based on the overall cost; where the overall cost represents the economic cost required to adopt the process path.

[0042] Specifically, the overall cost includes electricity costs caused by increased temperature, loss costs introduced by increased temperature and time, and labor costs introduced by increased time.

[0043] More specifically, the formula for calculating the overall cost is as follows: (1); Where i and j represent the number of temperature increases and the number of holding periods during the heating stage, respectively. t hi Let t be the heating time (in hours) for the i-th heating cycle. sj Let k be the insulation time (in hours) for the j-th time. h The heating element wear cost coefficient per unit heating time (yuan / hour) represents the cost of aging or damage to the furnace heating elements during the heating process. e P represents the electricity price (yuan / kWh). h P represents the furnace power (kW) during the heating phase. s The furnace power (kW) during the heat preservation stage, k mThe material failure cost coefficient per unit insulation time (yuan / hour) represents the failure cost caused by the reduction in lifespan due to high temperatures during the insulation process. l The cost per unit of time (yuan / hour) represents the human resource cost required to tend the furnace.

[0044] Assuming the total cost of the heating furnace is 1 million yuan and its service life is 20 years, the hourly depreciation cost of the furnace (kh) is approximately 5.71 yuan. Based on Beijing commercial electricity prices (c...),... e The price is 0.7883 yuan per kilowatt-hour. A single high-purity glass tube for the sample costs 35 yuan. Its service life is 150 hours at 1300℃ to 1400℃, 15 hours at 1400℃ to 1500℃, and only 2 hours above 1500℃. Therefore, k is obtained for each stage. m Value. The labor cost per unit time, c. l Approximately 50 yuan. The furnace power P during the heating phase. h P is equal to the product of the mass of the substance, its specific heat, and the heating rate. Here, the mass of the substance is 0.3 g, the specific heat is 30.6 J / kg / K, and the heating rate is 5 K / min. h Approximately 0.000765, during the heat preservation stage, the power output still needs to maintain a constant temperature, so let P be taken as... s For P h 20%. Therefore, given the heating temperature, holding temperature, and holding time, the estimated cost can be obtained by substituting them into Equation 5 above.

[0045] The rationality of the design method for the macroscopic morphology of metal melts provided by the present invention will be verified below with reference to specific embodiments.

[0046] Since the changes in supercooling of the samples used in the following embodiments are small before and after the application of the magnetic field, the supercooling ΔT stabilization process before the application of the magnetic field is ignored. The following embodiments are used to verify the rationality of the design method proposed in this invention.

[0047] Example 1: A method for designing the structure and microstructure of molten metal, using Co 83 B 17 Taking alloys as an example, the specific representation method is as follows: The sample was heated from room temperature to 1773 K at a rate of 5 ℃ / min under a static magnetic field strength of 3 T and a gradient magnetic field value of 23.235 T / m, and held at that temperature for 10 minutes. It was then cooled at the same rate, and this cycle was repeated 5 times until the collected data on temperature T and mass m0 over time t showed no significant fluctuations. Using the Faraday balance principle, the mass m0 was converted into the volumetric magnetic susceptibility χ (Equation 1), which was then multiplied by the magnetic field strength to obtain the magnetization M. The curves of M and T versus time t during the last melt treatment of the sample were recorded, as follows: Figure 2 As shown in a. During the heating phase, the melting point T is exceeded. L As temperature increases, M continuously decreases, and the curve of M versus t reaches an inflection point when the temperature reaches T0. From Figure 2 As shown in Figure b, the slope 1 / χ versus T curve shows a significant change in the curve slope at temperature T0 during the heating stage. The Curie constant C and Curie temperature θ corresponding to high-temperature melts above T0 are collected, as follows: Figure 3 As shown in Figure a, in this example, C is approximately 7.62 and θ is approximately 1114, which is consistent with the range of high-temperature melts with an L2 structure. The microstructure formed after the melt cools and solidifies is as follows: Figure 3 As shown in b, the overall microstructure is uniform and fine, exhibiting a near-equiaxed granular structure, consistent with the typical microstructure characteristics of L2 structure high-temperature melt after solidification. Based on the preliminary cost estimate, the final cost in this example is approximately 285.0141 yuan / hour.

[0048] Example 2: A method for designing the macroscopic morphology of metal melts, using Co 81.5 B 18.5 Taking alloys as an example, the specific representation method is as follows: The sample was heated from room temperature to T at a rate of 5 ℃ / min under a static magnetic field strength of 3 T and a gradient magnetic field value of 23.235 T / m. H = 1473 K, insulation t H = 2515 s, then heated to 1693 K at the same rate, held for 10 min, and repeated 5 times until the collected temperature T and mass m0 data with time t did not show significant fluctuations. Using the Faraday balance principle, the mass m0 was converted into the volume magnetic susceptibility χ (Equation 1), and multiplied by the magnetic field strength to obtain the magnetization M of the material. The curves of M and T with time t during the last melt treatment of the sample were recorded, as follows. Figure 4 As shown in a. During the heating phase, the melting point T is exceeded. L As time progresses, M continuously decreases, and when T... H = 1473 K heat preservation, M changes with heat preservation time t H As the temperature increases, the logarithmic change decreases. When the heat preservation process ends, as the temperature continues to increase, the curve of M versus t remains continuous without an inflection point. From Figure 4 The slope 1 / χ curve shown in b, along with the T variation curve, reveals the heating stage at T... H After holding at the temperature, the 1 / M value increases continuously with time until it reaches equilibrium. During subsequent temperature increases, it changes as a curve with a different slope and intercept. The Curie constant C and Curie temperature θ corresponding to the high-temperature melt are collected from this curve. Figure 5 As shown in Figure a, in this example, C is approximately 7.74 and θ is approximately 1135, which is consistent with the range of high-temperature melts with an L2 structure. The microstructure formed after the melt cools and solidifies is as follows: Figure 5As shown in b, the overall microstructure is uniform and fine, exhibiting a near-equiaxed granular structure, consistent with the typical microstructure characteristics of L2 structure high-temperature melt after solidification. Based on the preliminary cost estimate, the final cost in this example is approximately 303.9721 yuan / hour.

[0049] Example 3: A method for designing the macroscopic morphology of metal melts, using Co 83 B 17 Taking alloys as an example, the specific representation method is as follows: The sample was heated from room temperature to T at a rate of 5 ℃ / min under a static magnetic field strength of 3 T and a gradient magnetic field value of 23.235 T / m. H = 1565 K, insulation t H = 1454 s, then heated to 1779 K at the same rate, held for 10 min, and repeated 5 times until the collected temperature T and mass m0 data with time t did not show significant fluctuations. Using the Faraday balance principle, the mass m0 was converted into the volume magnetic susceptibility χ (Equation 1), and multiplied by the magnetic field strength to obtain the magnetization M of the material. The curves of M and T with time t during the last melt treatment of the sample were recorded, as follows. Figure 6 As shown in a. During the heating phase, the melting point T is exceeded. L As time progresses, M continuously decreases, and when T... H = When the temperature is maintained at 1565 K, M varies with the holding time t H As the temperature increases, the logarithmic change decreases. When the heat preservation process ends, as the temperature continues to increase, the curve of M versus t remains continuous without an inflection point. From Figure 6 The slope 1 / χ curve shown in b, along with the T variation curve, reveals the heating stage at T... H After holding at the temperature, the 1 / M value increases continuously with time until it reaches equilibrium. During subsequent temperature increases, it changes as a curve with a different slope and intercept. The Curie constant C and Curie temperature θ corresponding to the high-temperature melt are collected from this curve. Figure 7 As shown in Figure a, in this example, C is approximately 7.84 and θ is approximately 1137, which is consistent with the range of high-temperature melts with an L2 structure. The microstructure formed after the melt cools and solidifies is as follows: Figure 7 As shown in b, the overall microstructure is uniform and fine, exhibiting a near-equiaxed granular structure, consistent with the typical microstructure characteristics of L2 structure high-temperature melt after solidification. Based on the preliminary cost estimate, the final cost in this example is approximately 313.3983 yuan / hour.

[0050] Example 4: A method for designing the macroscopic morphology of metal melts, using Co 83 B 17 Taking alloys as an example, the specific representation method is as follows: The sample was heated from room temperature to T at a rate of 5 ℃ / min under a static magnetic field strength of 3 T and a gradient magnetic field value of 23.235 T / m. H = 1473 K, insulation t H = 2502 s, then heated to 1773 K at the same rate, held for 10 min, and repeated 5 times until the collected temperature T and mass m0 data with time t did not show significant fluctuations. Using the Faraday balance principle, the mass m0 was converted into the volume magnetic susceptibility χ (Equation 1), and multiplied by the magnetic field strength to obtain the magnetization M of the material. The curves of M and T with time t during the last melt treatment of the sample were recorded, as follows. Figure 8 As shown in a. During the heating phase, the melting point T is exceeded. L As time progresses, M continuously decreases, and when T... H = 1473 K heat preservation, M changes with heat preservation time t H As the temperature increases, the logarithmic change decreases. When the heat preservation process ends, as the temperature continues to increase, the curve of M versus t remains continuous without an inflection point. From Figure 8 The slope 1 / χ curve shown in b, along with the T variation curve, reveals the heating stage at T... H After holding at the temperature, the 1 / M value increases continuously with time until it reaches equilibrium. During subsequent temperature increases, it changes as a curve with a different slope and intercept. The Curie constant C and Curie temperature θ corresponding to the high-temperature melt are collected from this curve. Figure 9 As shown in Figure a, in this example, C is approximately 7.57 and θ is approximately 1128, which is consistent with the range of high-temperature melts with an L2 structure. The microstructure formed after the melt cools and solidifies is as follows: Figure 9 As shown in b, the overall microstructure is uniform and fine, exhibiting a near-equiaxed granular structure, consistent with the typical microstructure characteristics of L2 structure high-temperature melt after solidification. Based on the preliminary cost estimate, the final cost in this example is approximately 331.9942 yuan / hour.

[0051] Further, the final estimated costs in the above four cases were statistically analyzed, such as... Figure 10 As shown, the continuous heating method in Case 1 yields the lowest cost for obtaining the L2 structure, while the stepped heating-isothermal-heating methods in Cases 2, 3, and 4 are relatively more expensive. After process optimization, such as removing the subsequent heating process after obtaining the L2 structure through continuous heating in Case 1, isothermal heating in Case 2, and isothermal secondary heating in Cases 3 and 4, the optimized costs are 254.14, 245.76, 258.85, and 256.11 yuan / hour, respectively. In this case, the low-temperature holding method in Case 2 for obtaining the L2 structure is more advantageous. Therefore, by controlling the melt processing parameters, multiple melt structure types can be obtained through various paths, providing an important basis for judging the microstructure morphology and final performance, while also weighing the overall cost.

[0052] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method of designing a metal melt structure and micro solidification structure, characterized by, The method comprises the following steps: Step 1: placing a metal sample in a strong magnetic field material processing device and applying a target strong magnetic field; Step 2: performing multiple melt overheating and undercooling treatments until the collected temperature T and the mass of the sample in a solidification state under a magnetic field over time t do not fluctuate significantly, recording the m0-T-t curve of the last heating and cooling stage of the sample, and obtaining the paramagnetic-ferromagnetic Curie transition temperature θ and the Curie constant C of the melt according to the m0-T-t curve; Step 3: judging the melt structure according to the θ and C values obtained in Step 2, and recording the process path of the heating stage of the overheating and undercooling treatment when the melt is in a target structure; Step 4: heating the metal sample to be processed using the process path to obtain a melt with a target structure, and cooling to obtain a target microstructure.

2. The method of designing a metal melt structure and microsoliduied structure according to claim 1, wherein The method further comprises: Steps 2-3 are repeated multiple times, and only the process path of the heating stage of the melt overheating and undercooling treatment is changed each time, so as to obtain different process paths; The overall cost under different process paths is calculated, and the optimal process path is selected according to the overall cost; wherein the overall cost represents the economic cost consumed by using the process path.

3. The method of designing a metal melt structure and microsoliduied structure according to claim 2, wherein The overall cost includes the electricity cost caused by temperature rise, the loss cost introduced by temperature rise and time increase, and the human cost introduced by time increase.

4. The method of designing a metal melt structure and microsoliduied structure according to claim 2, wherein The calculation formula of the overall cost is as follows: ； in, i and j These represent the number of temperature increases and the number of heat holding cycles during the heating phase, respectively. t hi For the first i The time of each heating cycle t sj For the first j The duration of heat preservation, k h This is the cost coefficient for heating element losses per unit heating time. c e For electricity price, P h This refers to the furnace power during the heating phase. P s The furnace power during the heat preservation stage, k m The material failure cost coefficient per unit insulation time. c l This refers to the cost of human resources per unit of time.

5. The method of designing a metallic melt structure and microsoliduied structure of claim 1, wherein, The process path includes the number of temperature rises and holding times of the sample in the heating stage, the temperature rise rate and the temperature rise starting temperature at each temperature rise, and the holding temperature and time at each holding.

6. The method of designing a metallic melt structure and microsoliduie structure according to claim 1, wherein Before Step 1, the method further comprises: heating at a certain rate to the highest heating temperature, holding for a certain time to make the melt fully uniform, then cooling at the same rate, and repeating the above heating and cooling process until the undercooling degree ΔT measured continuously and repeatedly is stable.

7. The method of designing a metallic melt structure and microsoliduied structure of claim 1, wherein, The m0-T-t curve of the last heating and cooling stage of the sample is recorded by using a balance system matched with the strong magnetic field material processing device.

8. The method of designing a metallic melt structure and microsoliduie structure of claim 1, wherein, The calculation process of the paramagnetic-ferromagnetic Curie transition temperature θ and the Curie constant C is as follows: The m0 is converted into the magnetic susceptibility χ of the sample by using the Faraday balance principle, and the specific calculation formula is as follows: ； Wherein, g is the gravity of the sample in the magnetic field during solidification, m is the mass of the sample without a magnetic field, dH / dZ is the gradient magnetic field value of the sample at the corresponding position in the strong magnetic field material processing device, and H is the target magnetic field strength applied; A curve graph is drawn with the temperature T as the horizontal coordinate and the reciprocal of the magnetic susceptibility 1 / χ as the vertical coordinate, and the 1 / χ and T satisfy the Curie-Weiss relationship as follows: ； Linear fitting is performed on the drawn curve, and the curve slope k=1 / C and the intercept b=-θ / C of the temperature axis are obtained, and then C and θ are calculated by using the following formula: 。 9. The method of designing a metallic melt structure and microsoliduie structure of claim 1 wherein, In Step 3, when the metal sample is a Co-B alloy, the specific criterion for judging the melt structure is as follows: When the C and θ values satisfy the following formula (4) at the same time, the melt is in an L2 structure state; 7.45≤C≤8.05 1090≤θ≤1140 (4).

10. The method of designing a metallic melt structure and microsoliduie structure of claim 1 wherein, In Step 1, when the metal sample is placed, the sample is in an environment with a specific strong magnetic field strength H and a gradient magnetic field dH / dZ, and the direction of the gradient magnetic field is the same as that of the gravity.

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