Metallic glass performance analysis method and system based on improved viscoelastic model

Abstract

The invention belongs to the field of material science and engineering, and particularly relates to a metallic glass performance analysis method and system based on an improved viscoelastic model, aiming at viscoelastic behaviors, structural state evolution and relaxation dynamic characteristics of metallic glass under complex conditions. A traditional Maxwell model is improved by introducing a non-Newtonian unit, and characteristic relaxation time distribution caused by non-uniformity of a metal glass microstructure is considered, so that a set of complete analysis framework is established. The method is applied to performance analysis of the metallic glass under different strain amplitudes, temperatures and cyclic loading conditions; according to the method, the complex viscoelastic behavior of the metallic glass is accurately described, the viscoelastic behavior of the metallic glass under complex conditions can be accurately described, the influence of microstructure heterogeneity on relaxation dynamics is quantified, and a reliable performance evaluation method is provided for application of the metallic glass under extreme conditions.

Description

Technical Field

[0001] The present invention belongs to the field of materials science and engineering, and particularly relates to a method and system for analyzing the performance of metallic glasses based on an improved viscoelastic model for the viscoelastic behavior, structural state evolution, and relaxation dynamics characteristics of metallic glasses under complex conditions. Background Art

[0002] Metallic glasses are amorphous solids obtained by rapidly cooling molten alloys and have unique physical and mechanical properties. Due to their amorphous structure, metallic glasses exhibit high strength, high hardness, and excellent corrosion resistance, and are widely used in aerospace, electronic information, and other fields. However, traditional viscoelastic models (such as the Maxwell model), based on the assumptions of ideal elastic bodies and Newtonian fluids, cannot accurately describe the non-Newtonian rheological behavior of metallic glasses at low temperatures and high stresses. The main problems of the prior art include: the model cannot capture the non-linear relationship between stress and strain rate; it ignores the relaxation time distribution caused by microstructural inhomogeneity; and it lacks a quantitative analysis of the coupled effects of multiple factors (strain amplitude, temperature, cyclic loading).

[0003] The present invention provides a method and system for analyzing the performance of metallic glasses based on an improved viscoelastic model by improving the viscoelastic model and introducing a Gaussian distribution, which solves the above problems and provides a reliable tool for the performance evaluation and engineering application of metallic glasses. Summary of the Invention

[0004] The object of the present invention is to avoid the deficiencies of the prior art and provide a method and system for analyzing the performance of metallic glasses based on an improved viscoelastic model. By establishing a modified viscoelastic model and applying it to the performance analysis of metallic glasses under different strain amplitudes, temperatures, and cyclic loading conditions; by introducing a non-Newtonian unit and considering the characteristic relaxation time distribution caused by microstructural inhomogeneity, an accurate description of the complex viscoelastic behavior of metallic glasses is achieved.

[0005] To achieve the above object, the technical solution adopted by the present invention is a method for analyzing the performance of metallic glasses based on an improved viscoelastic model, including the following steps: Step 1, improve the traditional Maxwell model by introducing an Eyring-type non-Newtonian unit. By measuring the stress-strain curve of a metallic glass sample in a small strain range, obtain the elastic modulus , and then, according to the stress measurement data at different strain rates, combined with the Eyring law, preliminarily determine the reference stress and the reference strain rate , and obtain the modified viscoelastic constitutive equation. The differential form of the viscoelastic constitutive equation is: , wherein, is the stress, is the strain rate, is the reference stress, is the reference strain rate; Step 2: Considering the inhomogeneity of the microstructure of metallic glass, a continuous Gaussian distribution of characteristic relaxation times is adopted, expressed as: , wherein, is the characteristic relaxation time, is the most geometric characteristic time, is the variance; By using the stress relaxation experimental data of metallic glass at different temperatures and loading times, the modified Maxwell model is further improved to obtain the integral form of the stress relaxation process: ; Step 3: Using the above modified model, analyze the stress relaxation behavior, structural state changes, and relaxation dynamics of metallic glass under different strain amplitudes, temperatures, and cyclic loading conditions; Step 4: According to the differences between the experimental data and the model prediction results, optimize the model parameters, including adjusting the reference stress, reference strain, and Gaussian distribution parameters, to improve the model accuracy.

[0006] Furthermore, the analytical solution of the stress evolution with time of the modified Maxwell model in Step 1 under constant strain is: , where .

[0007] Furthermore, the derivation process of the analytical solution of the stress evolution with time of the modified Maxwell model under constant strain includes: Under constant strain conditions, the classical Maxwell model gives the stress evolution equation with time, , For metallic glass, experiments show that the relationship between its stress and strain rate is , rather than the relationship of Newtonian fluid. According to Eyring's law, its stress-strain rate relationship can be expressed as, , Thus, the Maxwell model is modified to obtain its differential form, , where is the elastic modulus. Further derivation gives the analytical solution of the stress evolution with time under constant strain as, , Here 。

[0008] Furthermore, in the first step, the stress-strain curve is obtained through tensile or compression experiments within a small strain range, and the elastic modulus is calculated according to the slope in the elastic stage; the reference stress and reference strain rate are determined by fitting the stress data at different strain rates.

[0009] Furthermore, in the second step, the Gaussian distribution parameters of the characteristic relaxation time are determined through statistical analysis and mathematical fitting of the stress relaxation experimental data.

[0010] Furthermore, in the third step, the stress relaxation behavior of the metallic glass under different strain amplitudes, temperatures, and cyclic loading conditions is analyzed, specifically including: at a fixed temperature and number of cyclic loadings, different strain amplitudes are applied, the stress relaxation data is measured and compared with the model prediction; multiple cyclic loading experiments are carried out at a specific temperature and strain amplitude to obtain the stress relaxation data and analyze the effect of the number of cycles on the structural evolution.

[0011] Furthermore, the optimization of the model parameters in the fourth step is to adjust the model parameters or improve the model structure according to the difference between the experimental data and the model results, so as to improve the description accuracy of the complex behavior of the metallic glass.

[0012] The present invention also provides a metallic glass performance analysis system for the metallic glass performance analysis method based on the improved viscoelastic model as described above, including a metallic glass sample preparation module for preparing metallic glass specimens with standard dimensions; an experimental control module for precisely controlling the strain amplitude, temperature, and cyclic loading conditions; a data acquisition module for real-time recording of stress, strain, and temperature data; a data analysis and model calculation module for determining model parameters according to the experimental data and performing model verification and optimization.

[0013] Furthermore, the process of metallic glass sample preparation and experimental setup includes: processing the metallic glass into standard specimens; calibrating the experimental equipment, setting the strain amplitude to 0.1% - 2%, the temperature range to 200 - 400 K, and the number of cycles range to 1 - 100 times; the data acquisition is to obtain the elastic modulus through tensile experiments; determining the Gaussian distribution parameters through stress relaxation experiments under constant strain; the model verification and optimization include: comparing the experimental data with the model prediction and calculating the error rate; if the error rate > 5%, then refitting the parameters or adjusting the model structure. The beneficial effects of the present invention are as follows: The present invention provides a method and system for analyzing the properties of metallic glasses based on an improved viscoelastic model. By improving the viscoelastic model and introducing a Gaussian distribution, a modified viscoelastic model is established and applied to the property analysis of metallic glasses under different strain amplitudes, temperatures, and cyclic loading conditions. By introducing a non-Newtonian element and considering the characteristic relaxation time distribution caused by microstructural inhomogeneity, an accurate description of the complex viscoelastic behavior of metallic glasses can be achieved, and the viscoelastic behavior of metallic glasses under complex conditions can be accurately described, and the influence of microstructural inhomogeneity on relaxation dynamics can be quantified, providing a reliable method for performance evaluation of metallic glasses under extreme conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the implementation process of the present invention; Figure 2 is the evolution curve of normalized stress relaxation over time and the corresponding fitting curve obtained in the embodiment of the present invention; Figure 3 is the analysis result of the structural state parameters of the metallic glass obtained in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0016] To achieve the above object, the present invention provides the following specific embodiments, as Figure 1 shown, a method for analyzing the properties of metallic glasses based on an improved viscoelastic model includes the following steps: Step 1: Improve the traditional Maxwell model by introducing an Eyring-type non-Newtonian element. Obtain the elastic modulus by measuring the stress-strain curve of the metallic glass sample in the small strain range , and based on the stress measurement data at different strain rates, combined with the Eyring law, preliminarily determine the reference stress and the reference strain rate through data fitting, and obtain the modified viscoelastic constitutive equation, whose differential form is: , where is the stress, is the strain rate, is the reference stress, is the reference strain rate; Step 2: Considering the microstructural inhomogeneity of metallic glasses, adopt a continuous Gaussian distribution of characteristic relaxation time, expressed as: , where is the characteristic relaxation time, is the most geometric characteristic time, is the variance; These parameters are determined by statistical analysis and mathematical analysis of the stress relaxation experimental data of metallic glass at different temperatures and loading times, and the modified Maxwell model is further improved to obtain the integral form of the stress relaxation process: ; Step 3: Using the above modified model, analyze the stress relaxation behavior, structural state change, and relaxation dynamics of metallic glass under different strain amplitudes, temperatures, and cyclic loading conditions; Step 4: According to the differences between the experimental data and the model prediction results, optimize the model parameters, including adjusting the reference stress, reference strain, and Gaussian distribution parameters, to improve the model accuracy.

[0017] Furthermore, the analytical solution of the stress evolution with time of the modified Maxwell model in step 1 under constant strain is , where ; the theoretical basis of the above model is that in the traditional viscoelastic model theory, the viscoelasticity of materials is simulated by combining springs and dampers in different ways. The Maxwell model connects an elastic spring and a Newtonian fluid in series to describe the interaction between the elastic and viscous aspects of materials. However, for metallic glass, its viscous part has non-Newtonian characteristics. Therefore, the present invention introduces an Eyring-type non-Newtonian unit to better describe the actual viscoelastic behavior of metallic glass.

[0018] The derivation process of the analytical solution of the stress evolution with time of the modified Maxwell model under constant strain includes: Under constant strain conditions, the classical Maxwell model gives the stress evolution equation with time, , For metallic glass, experiments show that its stress-strain rate relationship is , not the relationship of Newtonian fluid. According to Eyring's law, its stress-strain rate relationship can be expressed as , Therefore, the Maxwell model is modified to obtain its differential form , where is the elastic modulus. Further derivation gives the analytical solution of the stress evolution with time under constant strain as , where .

[0019] Further, in the first step, the stress-strain curve is obtained through tensile or compression experiments within a small strain range, and the elastic modulus is calculated according to the slope in the elastic stage; the reference stress and reference strain rate are determined by fitting the stress data at different strain rates.

[0020] Further, in the second step, the Gaussian distribution parameters of the characteristic relaxation time are determined through statistical analysis and mathematical fitting of the stress relaxation experimental data.

[0021] Further, in the third step, the stress relaxation behavior of the metallic glass under different strain amplitudes, temperatures, and cyclic loading conditions is analyzed, specifically including: at a fixed temperature and number of cyclic loadings, different strain amplitudes are applied, the stress relaxation data is measured and compared with the model prediction; multiple cyclic loading experiments are carried out at a specific temperature and strain amplitude to obtain the stress relaxation data and analyze the effect of the number of cycles on the structural evolution.

[0022] Further, the optimization of the model parameters in the fourth step is to adjust the model parameters or improve the model structure according to the difference between the experimental data and the model results, so as to improve the description accuracy of the complex behavior of the metallic glass.

[0023] Embodiment 2: The present invention also provides an analysis system for the performance analysis method of metallic glass based on the improved viscoelastic model as described above, including a metallic glass sample preparation module for preparing metallic glass specimens with standard dimensions, an experimental control module for precisely controlling the strain amplitude, temperature, and cyclic loading conditions, a data acquisition module for real-time recording of stress, strain, and temperature data, and a data analysis and model calculation module for determining model parameters according to the experimental data and performing model verification and optimization.

[0024] Further, the process of sample preparation and experimental setup includes: processing the metallic glass into standard specimens; calibrating the experimental equipment, setting the strain amplitude to 0.1% - 2%, the temperature range to 200 - 400 K, and the number of cycles range to 1 - 100 times; the data acquisition is to obtain the elastic modulus through tensile experiments; the Gaussian distribution parameters are determined through stress relaxation experiments under constant strain; the model verification and optimization include: comparing the experimental data with the model prediction and calculating the error rate; if the error rate > 5%, then refitting the parameters or adjusting the model structure.

[0025] As Figure 2The obtained evolution curves of normalized stress relaxation with time and the corresponding fitting curves are shown. The hollow squares, hollow circles, and hollow triangles in the figure respectively represent the experimental data of the normalized stress relaxation of metallic glass with time after 1, 5, and 9 cyclic loadings. One cycle includes loading at a constant strain for 30 minutes and then unloading and recovering for 10 minutes. The solid lines represent the fitting curves of the stress relaxation behavior of metallic glass after cyclic loading obtained by the method of the present invention. As the number of cycles increases, the relaxation dynamics of metallic glass gradually slows down and the structural state changes; As Figure 3 shown is the analysis result of the structural state parameters of metallic glass. The data points in the figure represent the evolution of the normalized reference strain rate of metallic glass after cyclic loading obtained by the method of the present invention with the number of cycles. As the number of cycles increases, the normalized reference strain rate shows an exponential decrease, indicating obvious differences in relaxation dynamics. As the number of cycles increases, metallic glass gradually hardens, the atomic mobility significantly slows down, and finally tends to be stable.

[0026] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for analyzing metallic glass performance based on an improved viscoelastic model, characterized in that: The following steps are involved: Step 1: Improve the traditional Maxwell model by introducing Eyring-type non-Newtonian units, and obtain the elastic modulus by measuring the stress-strain curve of the metallic glass sample in a small strain range. Then, based on the stress measurement data at different strain rates and combined with Eyring's law, the reference stress is preliminarily determined by data fitting. and the reference strain rate , the modified viscoelastic constitutive equation is obtained, and the differential form of the viscoelastic constitutive equation is: ， In the formula, is stress, is the strain rate, is the reference stress, is the reference strain rate; Step 2: Considering the inhomogeneity of the microstructure of metallic glass, a continuous Gaussian distribution of characteristic relaxation time is used, expressed as: ， In the formula, is the characteristic relaxation time, is the most geometric characteristic time, is the variance; Through the stress relaxation experimental data of metallic glass at different temperatures and loading times, the modified Maxwell model is further improved to obtain the integral form of the stress relaxation process: ； Step 3, using the above modified model, analyze the stress relaxation behavior, structural state change and relaxation dynamics of metallic glass under different strain amplitudes, temperatures and cyclic loading conditions; Step 4: According to the difference between the experimental data and the model prediction results, the model parameters are optimized, including adjusting the reference stress, reference strain and Gaussian distribution parameters to improve the model accuracy.

2. A method for analyzing metallic glass properties based on an improved viscoelastic model according to claim 1, characterized in that: The analytical solution of the stress evolution over time of the modified Maxwell model in step 1 under constant strain is: ,in .

3. A method for analyzing metallic glass properties based on an improved viscoelastic model as claimed in claim 2, characterized in that: The derivation process of the analytical solution of the stress evolution with time under constant strain of the modified Maxwell model includes: Under constant strain conditions, the classical Maxwell model gives the equation for the evolution of stress over time: ， For metallic glass, experiments show that the stress-strain relationship is , not a Newtonian fluid According to Eyring's law, the stress-strain rate relationship can be expressed as: ， Therefore, the Maxwell model is modified to obtain its differential form: ， in is the elastic modulus. Further deduction shows that the analytical solution of the stress evolution with time under constant strain is: ， here .

4. The method for analyzing metallic glass properties based on an improved viscoelastic model according to claim 1, characterized in that: In the step 1, a stress-strain curve is obtained through a tensile or compression experiment within a small strain range, and the elastic modulus is calculated according to the slope of the elastic stage; and a reference stress and a reference strain rate are determined by fitting stress data at different strain rates.

5. The method for analyzing metallic glass properties based on an improved viscoelastic model according to claim 1, characterized in that: In step 2, the Gaussian distribution parameters of the characteristic relaxation time are determined through statistical analysis and mathematical fitting of the stress relaxation experimental data.

6. The method for analyzing metallic glass properties based on an improved viscoelastic model according to claim 1, characterized in that: The step three analyzes the stress relaxation behavior of metallic glass under different strain amplitudes, temperatures and cyclic loading conditions, specifically including: applying different strain amplitudes at a fixed temperature and number of cyclic loadings, measuring stress relaxation data and comparing them with model predictions; performing multiple cyclic loading experiments at specific temperatures and strain amplitudes, obtaining stress relaxation data and analyzing the effect of the number of cycles on structural evolution.

7. A method for analyzing metallic glass properties based on an improved viscoelastic model according to any one of claims 1 to 6, characterized in that: The optimization of model parameters in step 4 is to adjust model parameters or improve model structure according to the difference between experimental data and model results, so as to improve the accuracy of describing the complex behavior of metallic glass.

8. A metallic glass performance analysis system according to the metallic glass performance analysis method based on the improved viscoelastic model as claimed in claims 1 to 7, characterized in that: It includes a metallic glass sample preparation module for preparing metallic glass samples of standard size; an experimental control module for accurately controlling strain amplitude, temperature and cyclic loading conditions; and a data acquisition module for real-time recording of stress, strain and temperature data; The data analysis and model calculation module determines the model parameters based on the experimental data and performs model verification and optimization.

9. The metallic glass performance analysis system according to claim 8, characterized in that: The metallic glass sample preparation and experimental setting process includes: processing the metallic glass into a standard sample; calibrating the experimental equipment, setting the strain amplitude to 0.1%-2%, the temperature range to 200-400 K and the number of cycles to 1-100 times; the data acquisition is to obtain the elastic modulus through a tensile experiment; and the Gaussian distribution parameters are determined through a stress relaxation experiment under constant strain. The model verification and optimization includes: comparing the experimental data with the model prediction and calculating the error rate; if the error rate is >5%, refitting the parameters or adjusting the model structure.

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