Method for monitoring temperature in cold and hot cycling process

Abstract

The invention relates to the technical field of amorphous alloy mechanical property regulation and control, and discloses a method for monitoring temperature in a cold and hot cycling process, which comprises the following steps: placing an iron-based amorphous alloy sample in a cold and hot cycling device; collecting surface temperature field data of the sample in real time through an infrared thermal imaging device coaxially integrated in the thermal circulation system; cooling and heating alternate circulation treatment is carried out in a set temperature interval; synchronously recording space-time distribution data of the surface temperature of the sample in the circulation process; establishing an energy state evolution function according to the temperature field evolution data; and when the fluctuation ratio delta E / E of the energy state function of three continuous cycle periods is less than 5%, judging that the sample reaches an energy saturation state. By integrating an advanced temperature monitoring technology and a scientific and reasonable cold and heat cycle scheme, high-precision and real-time monitoring and quantitative analysis of the energy state evolution process of the iron-based amorphous alloy are realized, and optimization of a heat treatment process of the amorphous alloy and improvement of material performance are greatly promoted.

Description

Technical Field

[0001] This invention relates to the field of mechanical property control technology for amorphous alloys, specifically a method for temperature monitoring during thermal cycling. Background Technology

[0002] Iron-based amorphous alloys, due to their excellent soft magnetic properties, high strength, and good corrosion resistance, have broad application prospects in fields such as power electronics, information technology, new energy, and aerospace. The amorphous structure endows iron-based amorphous alloys with unique physical and chemical properties, but the stability and controllability of these properties largely depend on the internal energy state of the material and its evolution. Especially during heat treatment, thermodynamic processes such as material relaxation, nanocrystallization, and phase transformation play a crucial role in the final properties of the alloy.

[0003] Traditional heat treatment processes for iron-based amorphous alloys often rely on fixed temperature-time parameters, lacking real-time monitoring and dynamic analysis methods for the internal thermal state and energy evolution of the material. Existing technologies typically employ differential scanning calorimetry (DSC), X-ray diffraction (XRD), and transmission electron microscopy (TEM) for offline characterization of material structural changes. However, these methods struggle to achieve non-destructive, real-time monitoring of the entire heat treatment process and cannot directly reflect the internal temperature gradient and energy distribution of the material.

[0004] Furthermore, traditional temperature measurement methods are mostly limited to point measurements or two-dimensional surface measurements, making it difficult to accurately obtain the three-dimensional temperature field distribution of materials during complex thermal cycling processes. This results in blind spots in the understanding of the material's thermal conduction behavior and energy state evolution. The lack of high spatial and temporal resolution temperature field data limits in-depth research on the heat treatment mechanism of iron-based amorphous alloys and process optimization.

[0005] Currently, laser heating and liquid nitrogen rapid cooling technologies have been widely used in the heat treatment of amorphous alloys to achieve precise control of rapid heating and rapid cooling. However, the related temperature monitoring and energy state characterization methods are still imperfect and cannot meet the needs of high-precision and high-efficiency industrial applications.

[0006] Therefore, there is an urgent need for a technical means to monitor the temperature field of iron-based amorphous alloys in real time and with high precision throughout the heat treatment process. By combining scientific heat conduction models and energy state analysis methods, we can achieve accurate inversion and dynamic evaluation of the internal temperature gradient and energy state evolution of the material, thereby providing theoretical basis and technical support for material performance optimization and heat treatment process design.

[0007] This invention was proposed against the backdrop of the aforementioned technology. By integrating high-resolution infrared thermal imaging technology with a laser heating-liquid nitrogen cooling composite thermal cycle system, and combining a three-dimensional transient heat conduction model and energy evolution function, it innovatively realizes real-time monitoring and dynamic analysis of the energy state of iron-based amorphous alloys. This overcomes the shortcomings of traditional technologies and significantly improves the controllability of the heat treatment process and the optimization effect of material properties. Summary of the Invention

[0008] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a method for temperature monitoring during thermal cycling, thereby solving the aforementioned problems.

[0009] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a method for temperature monitoring during a thermal cycling process, comprising the following steps: (1) Place the iron-based amorphous alloy sample in a hot and cold cycle device; (2) The sample surface temperature field data are collected in real time by an infrared thermal imaging device coaxially integrated into the thermal cycling system. The line of sight of the infrared thermal imaging device is coaxial with the heat treatment area of ​​the sample. (3) Perform alternating hot and cold cycle processing within a set temperature range. Each cycle includes: Increase the temperature to T4 at a rate of 10-100℃ / min (150℃≤T1≤T). x T x (Crystallization initiation temperature) Keep warm for T4 minutes (1≤t1≤30) Cool to T2 at a rate of 20-150℃ / min (-50℃≤T2≤50℃). Keep warm for T2 minutes (1≤t2≤20); (4) Record the spatiotemporal distribution data of the sample surface temperature during the cycle, and calculate the internal temperature gradient of the sample by inverting the heat conduction model. (5) Establish the energy state evolution function based on the temperature field evolution data: Where κ is thermal conductivity, ρ is density, and c p Specific heat capacity; (6) When the energy state function fluctuation rate ΔE / E < 5% for three consecutive cycles, the sample is determined to have reached the energy saturation state.

[0010] As a preferred technical solution of the present invention, the infrared thermal imaging device in step (2) operates in a band of 3-5μm, has a spatial resolution better than 50μm / pixel, and a temperature sampling frequency ≥10Hz.

[0011] As a preferred technical solution of the present invention, the number of hot and cold cycles in step (3) is 10-500 times, and the temperature control accuracy is ±1℃.

[0012] As a preferred technical solution of the present invention, the temperature field is reconstructed in step (4) using a three-dimensional transient heat conduction equation: The boundary conditions are determined by the surface temperature measured by an infrared thermal imager.

[0013] As a preferred technical solution of the present invention, a structural relaxation factor is introduced in step (5). When the value of α stabilizes within the range of ±0.03, the energy state is considered to have reached equilibrium.

[0014] As a preferred technical solution of the present invention, the hot and cold circulation device is a laser heating-liquid nitrogen cooling composite system, wherein the heating source is a 500-2000W fiber laser with an adjustable spot diameter of 0.5-5mm.

[0015] Compared with the prior art, the present invention provides a method for temperature monitoring during a thermal cycle, which has the following beneficial effects: Real-time, high-resolution temperature field monitoring: This invention uses a mid-wave infrared thermal imaging device with a working wavelength of 3-5μm, which has a spatial resolution of better than 50μm / pixel and a temperature sampling frequency of ≥10Hz. It can accurately capture the spatiotemporal distribution characteristics of the sample surface temperature, effectively reflect the dynamic thermal response of the material during the thermal cycling process, and improve the reliability and detail of the temperature field data.

[0016] Accurate 3D temperature field reconstruction and internal temperature gradient inversion: By introducing a 3D transient heat conduction equation and combining it with the boundary temperature conditions measured by an infrared thermal imager, high-precision numerical simulation and inversion of the internal temperature field of the sample were achieved. This overcomes the limitations of traditional single-point or 2D temperature measurement methods, comprehensively reveals the internal heat conduction mechanism and temperature gradient changes of the material, and provides a solid theoretical and data foundation for energy state analysis.

[0017] A complete hot and cold cycle heat treatment scheme and temperature control: This invention designs a reasonable hot and cold alternating cycle program, covering all stages of heating, holding, cooling, and low-temperature holding. The temperature control accuracy is as high as ±1℃, and the number of cycles is wide (10-500 times), meeting the needs of different materials and processes. The application of a laser heating and liquid nitrogen cooling composite system enables rapid switching between heating and cooling, improving experimental efficiency and the uniformity of heat treatment.

[0018] Innovative Energy State Evolution Function and Structural Relaxation Factor Introduction: Based on temperature field data, an energy state evolution function incorporating thermal conductivity, density, and specific heat capacity was established. The structural relaxation factor α was introduced as an energy state equilibrium criterion, effectively quantifying the energy change trend and stability of materials during cycling. This method provides a new perspective and quantitative means for analyzing the internal structural evolution and thermodynamic state of materials.

[0019] Accurate determination of energy saturation state: By using the criterion that the energy state function fluctuation rate ΔE / E < 5% for three consecutive cycles, combined with the stability of the structural relaxation factor α, the accurate identification of the energy saturation state of the material is achieved, avoiding the subjectivity and uncertainty of traditional empirical judgment, and improving the scientificity and repeatability of experimental results.

[0020] The method boasts wide applicability and flexibility: This invention is applicable to energy state monitoring of various iron-based amorphous alloys, and the parameters can be flexibly adjusted according to specific material characteristics, exhibiting excellent scalability and adaptability. The configuration of the laser heating-liquid nitrogen cooling composite system and the integration of infrared thermal imaging technology ensure the advanced nature of the experimental setup and ease of operation.

[0021] In summary, this invention, by integrating advanced temperature monitoring technology and a scientifically sound thermal cycling scheme, achieves high-precision, real-time monitoring and quantitative analysis of the energy state evolution process of iron-based amorphous alloys. This significantly promotes the optimization of heat treatment processes and the improvement of material properties in amorphous alloys. This method not only contributes to a deeper understanding of the thermodynamic behavior and structural evolution mechanism of iron-based amorphous alloys but also provides important technical support and theoretical basis for the development and application of related materials, possessing broad application prospects and promotional value. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the method steps of the present invention. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the invention, and not all of them. Unless otherwise specified, the embodiments and features described in this application can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] Furthermore, "multiple" refers to two or more. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of a person skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the invention.

[0025] Please see Figure 1 A method for temperature monitoring during thermal cycling. 1. Preparation of equipment and materials In implementing this invention, a sample of an iron-based amorphous alloy is first prepared, such as an iron-based amorphous alloy strip or sheet, the dimensions of which can be adjusted according to experimental requirements (e.g., thickness 0.02-0.1 mm, diameter 10-50 mm). The sample is placed in a thermal cycling device, which employs a laser heating-liquid nitrogen cooling composite system. The heating source is a fiber laser with a power of 500-2000 W, and the spot diameter is adjustable from 0.5-5 mm to achieve precise localized heating. Liquid nitrogen is used as the cooling source to ensure rapid cooling.

[0026] Simultaneously, an infrared thermal imaging device is integrated into the thermal cycling system. The device's line of sight is coaxial with the sample's heat-treated area, enabling real-time acquisition of the sample surface temperature field data. Specific parameters include: a working wavelength of 3-5 μm, a spatial resolution better than 50 μm / pixel, and a temperature sampling frequency of no less than 10 Hz. These parameters ensure the accuracy and real-time performance of the temperature field data.

[0027] The temperature control system must ensure that the temperature control accuracy is ±1℃ throughout the process in order to avoid the influence of external interference on the experimental results.

[0028] 2. Experimental Procedure The implementation process of this invention includes the following specific steps: (1) Sample placement The iron-based amorphous alloy sample was fixed in the heat treatment area of ​​the thermal cycling device, ensuring full contact between the sample and the heating and cooling components of the device. The sample surface must be clean and free of oxide layer to ensure accurate acquisition by the infrared thermal imaging device.

[0029] (2) Temperature field data acquisition The infrared thermal imaging device is activated and, through its coaxial integration with the thermal cycling system, monitors the temperature field of the sample surface in real time. The device operates in the 3-5 μm wavelength range, with a spatial resolution better than 50 μm / pixel and a temperature sampling frequency ≥10 Hz, ensuring high spatial and temporal resolution of the acquired temperature data. The acquired data includes temperature distribution images and time-series data of the sample surface.

[0030] (3) Alternating hot and cold cycle treatment Within a set temperature range, the sample is subjected to alternating hot and cold treatment cycles, with a total number of cycles set to 10-500. The specific procedure for each cycle is as follows: Increase the temperature to T4 at a rate of 10-100℃ / min (where 150℃≤T4≤T). x Tx The crystallization initiation temperature of iron-based amorphous alloys is typically determined based on the sample characteristics and is usually between 300-400℃. Keep warm at temperature T4 for t4 minutes (where 1≤t4≤30). It is then cooled to T2 at a rate of 20-150℃ / min (where -50℃≤T2≤50℃); Keep warm at temperature T2 for t2 minutes (where 1≤t2≤20).

[0031] The temperature control accuracy throughout the process is ±1℃ to ensure the stability and repeatability of the cycle. For example, in a typical embodiment, the heating rate can be selected as 50℃ / min to T4=250℃, held for 10 minutes; the cooling rate can be selected as 100℃ / min to T2=20℃, held for 5 minutes; the total number of cycles is 100.

[0032] (4) Data recording and internal temperature calculation During the thermal cycling process, the spatiotemporal distribution data of the sample surface temperature were recorded simultaneously, including temperature field images and time series. Based on this data, the internal temperature gradient of the sample was calculated using a heat conduction model. Specifically, a three-dimensional transient heat conduction equation was used to reconstruct the temperature field: Where ρ is the sample density, c p Let κx be the specific heat capacity, and κy, κz be the thermal conductivity in the x, y, and z directions, respectively. Boundary conditions are determined from surface temperature data measured by an infrared thermal imaging device. The temperature distribution inside the sample is reconstructed by solving this equation using numerical simulation software (such as finite element analysis tools). For example, typical thermophysical parameters of the sample can be used in the calculation:

[0033] (5) Establishment of the energy state evolution function Based on the collected temperature field evolution data, an energy state evolution function for iron-based amorphous alloys is established: Where κ is thermal conductivity, ρ is density, and c p Let T(t,x,y) be the specific heat capacity, and T(t,x,y) be the temperature field function, with the integration range being the sample volume V. The value of E for each cycle is calculated through numerical integration. Furthermore, a structural relaxation factor is introduced. E n Let α be the energy state value in the nth cycle, and E0 be the initial energy state value. When the value of α stabilizes within ±0.03, the energy state is considered to have reached equilibrium. For example, in the experiment, the change in the value of α was continuously monitored to observe its gradual stabilization from the initial fluctuations.

[0034] (6) Determination of energy saturation state After completing the preset cycle, the volatility of the energy state function E is analyzed. The volatility ΔE / E (where ΔE is the standard deviation of the E value) is calculated for three consecutive cycles. When ΔE / E < 5%, the sample is considered to have reached energy saturation. For example, in one embodiment, after 150 cycles, the volatility of the E value drops to 3.2%, satisfying the α stability condition, at which point the experiment is terminated.

[0035] 3. Implementation Example The following is a specific implementation example to further illustrate the present invention: Sample: Fe78Si9B13 amorphous alloy thin strip, dimensions φ20mm×0.05mm.

[0036] Hot and cold cycle parameters: 200 cycles; heating to T4=220℃ (rate 40℃ / min), holding for 15 minutes; cooling to T2=0℃ (rate 80℃ / min), holding for 8 minutes.

[0037] Infrared thermal imaging device: operating band 3-5μm, spatial resolution 40μm / pixel, sampling frequency 15Hz.

[0038] Through the above steps, the calculated energy state function E stabilizes after 180 cycles, with a volatility ΔE / E = 2.5% and α = 0.01, confirming that the sample has reached an energy saturation state.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0040] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0041] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for monitoring temperature during a thermal cycling process, characterized in that... Includes the following steps: (1) Place the iron-based amorphous alloy sample in a hot and cold cycle device; (2) The sample surface temperature field data are collected in real time by an infrared thermal imaging device coaxially integrated into the thermal cycling system, wherein the line of sight of the infrared thermal imaging device is coaxial with the heat treatment area of ​​the sample. (3) Perform alternating hot and cold cycle processing within a set temperature range. Each cycle includes: Increase the temperature to T4 at a rate of 10-100℃ / min (150℃≤T1≤T). x T x (Crystallization initiation temperature) Keep warm for T4 minutes (1≤t1≤30) Cool to T2 at a rate of 20-150℃ / min (-50℃≤T2≤50℃). Keep warm for T2 minutes (1≤t2≤20); (4) Record the spatiotemporal distribution data of the sample surface temperature during the cycle, and calculate the internal temperature gradient of the sample by inverting the heat conduction model. (5) Establish the energy state evolution function based on the temperature field evolution data: Where κ is thermal conductivity, ρ is density, and c p Specific heat capacity; (6) When the energy state function fluctuation rate ΔE / E < 5% for three consecutive cycles, the sample is determined to have reached the energy saturation state.

2. The method for temperature monitoring during a thermal cycling process according to claim 1, characterized in that: In step (2), the infrared thermal imaging device operates in the 3-5μm band, has a spatial resolution better than 50μm / pixel, and a temperature sampling frequency ≥10Hz.

3. The method for temperature monitoring during a thermal cycling process according to claim 1, characterized in that: In step (3), the number of hot and cold cycles is 10-500 times, and the temperature control accuracy is ±1℃.

4. The method for temperature monitoring during a thermal cycling process according to claim 1, characterized in that: In step (4), the temperature field is reconstructed using a three-dimensional transient heat conduction equation: The boundary conditions are determined by the surface temperature measured by an infrared thermal imager.

5. The method for temperature monitoring during a thermal cycling process according to claim 1, characterized in that: In step (5), a structural relaxation factor is introduced. When the value of α stabilizes within the range of ±0.03, the energy state is considered to have reached equilibrium.

6. The method for temperature monitoring during a thermal cycling process according to claim 1, characterized in that: The heating and cooling system is a laser heating-liquid nitrogen cooling composite system, wherein the heating source is a 500-2000W fiber laser with an adjustable spot diameter of 0.5-5mm.

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