Method for calculating high-temperature elastic-plastic constitutive behavior and toughness characteristic of crystal-amorphous biphase metal based on deformation mechanism and microstructure composition

Abstract

The invention discloses a method for calculating high-temperature elastic-plastic constitutive behaviors and toughness characteristics of crystal-amorphous double-phase metal based on a deformation mechanism and microstructure composition, which is based on an elastic-plastic theoretical framework, considers the deformation mechanism and the microstructure composition, realizes numerical calculation through MATLAB (matrix laboratory), and calculates the high-temperature elastic-plastic constitutive behaviors and toughness characteristics of the crystal-amorphous double-phase metal based on the deformation mechanism and the microstructure composition. And the high-temperature uniaxial stretching / compression elastic-plastic constitutive behavior and the toughness characteristic of the crystal-amorphous biphase metal are simulated and predicted. According to the method, microstructure characteristics such as metal internal grain size, dislocation density evolution, microcrack generation and evolution and amorphous integral number evolution along with temperature are considered, and high-temperature uniaxial tension / compression elastic-plastic constitutive behaviors and toughness characteristics of metal materials with microstructures composed of crystal phases and amorphous phases are simulated and predicted. In the preparation of a crystal-amorphous biphase metal material and a high-temperature mechanical property measurement experiment, a theoretical basis is provided for the high-temperature tensile / compressive property change of the crystal-amorphous biphase metal, and a theoretical guidance can be provided for improving the high-temperature mechanical property of the crystal-amorphous biphase metal.

Description

Technical Field

[0001] The present invention belongs to the field of simulation of tensile / compressive constitutive behavior and toughness properties of metals in high-temperature environments, and in particular relates to a method for calculating the high-temperature elastic-plastic constitutive behavior and toughness properties of crystal-amorphous dual-phase metals based on deformation mechanism and microstructure composition. Background Art

[0002] With the continuous improvement of social productivity, all walks of life have put forward higher requirements for the mechanical properties of materials, such as high-temperature toughness. The development of materials science and the advancement of industrial production technology have enabled humans to improve the comprehensive performance of materials by changing the microstructure of materials. In 1981, Professor H. Gleiter of Saarland University in Germany first proposed the concept of "nanostructured materials" and successfully prepared nano-microcrystalline blocks in 1984, explaining the structural characteristics of nanostructured materials. In 2017, Professor Lu Jian of the City University of Hong Kong proposed a crystal-amorphous dual-phase ultra-nanostructured metal material. This nanostructured metal has excellent mechanical properties. Generally speaking, nanostructured metal materials usually have very high strength and hardness. The increase in strength and hardness will reduce the toughness and work hardening ability of the material, which limits the development and application of nanostructured metal materials.

[0003] The crystal-amorphous dual-phase structure in the microstructural distribution of the material allows one or more properties of the material to be improved without losing the original properties, which provides a good idea for improving the comprehensive performance of the material. The microstructural composition characteristics of crystal-amorphous dual-phase metal materials give them excellent mechanical properties, making crystal-amorphous dual-phase structure metals a hot research topic in materials science. Metal materials exhibit melting behavior in high-temperature environments, and the amorphous phase inside the material increases with increasing temperature, causing the metal material to form a crystal-amorphous dual-phase structure. In view of the deformation behavior and mechanical properties of these crystal-amorphous dual-phase metals, it is urgent to establish a corresponding theoretical system to describe the comprehensive characteristics of the material, so as to guide and predict practical applications. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies of the prior art and provide a method for calculating the high-temperature elastic-plastic constitutive behavior and toughness properties of crystalline-amorphous dual-phase metals based on deformation mechanism and microstructure composition.

[0005] The object of the present invention is achieved through the following technical solution: a method for calculating the high-temperature elastic-plastic constitutive behavior and toughness characteristics of a crystalline-amorphous dual-phase metal based on deformation mechanism and microstructure composition, comprising the following steps:

[0006] (1) Obtain the material parameters and structural information of the metal material through experimental characterization, obtain the true stress-strain curve of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material, and set the initial conditions of the metal material;

[0007] (2) By adjusting the sensitivity coefficient m and the grain strain gradient parameter SGGB in the dynamic crystal phase constitutive model, the number of dislocations N or the dislocation slip length coefficient Lamdan in the back stress model, and the Weber modulus or microcrack density in the microcrack failure model parameters, the real stress-strain curves of the elastic, yield, strengthening, and failure stages of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material are simulated and fitted, and all the final model parameters are determined;

[0008] (3) Based on the material parameters and model parameters determined in steps (1) and (2), the grain size and ambient temperature are changed to predict the effect of grain size on the high-temperature tensile / compressive elastoplastic constitutive behavior and toughness properties of the material when the amorphous phase size is uniformly distributed.

[0009] Furthermore, the step (1) specifically includes the following sub-steps:

[0010] (1.1) obtaining material parameters and structural information of the metal material through experimental characterization, wherein the material parameters include the elastic modulus, Poisson's ratio, Burger vector, Taylor parameter, and yield strength of coarse grains of the metal material, and the structural information includes grain size, amorphous phase scale, and amorphous phase volume fraction;

[0011] The metal material is a crystalline-amorphous dual-phase metal material;

[0012] The high-temperature engineering stress-strain curve of crystalline-amorphous dual-phase metal materials was obtained through experimental characterization;

[0013] (1.2) Converting the high-temperature engineering stress-strain curve of the crystalline-amorphous dual-phase metal material into the real stress-strain curve of the high-temperature uniaxial tension / compression of the crystalline-amorphous dual-phase metal material obtained by experimental characterization;

[0014] Then, the shear modulus and bulk modulus of the metal material are calculated based on the elastic modulus and Poisson's ratio. The temperature-dependent changes in the size and volume fraction of the discrete metal material microstructures measured experimentally are then fitted with a continuous function curve to obtain the relationship curves between the size and temperature changes of the microstructures in the metal material and the relationship curves between the volume fraction and temperature changes of the microstructures in the metal material.

[0015] (1.3) Set the initial conditions of the metal material: the true elastic stress, true elastic strain, true plastic stress and true plastic strain of the metal material are all set to 0, the dislocation density of the metal material is normalized and set to 1, the strain loading of the metal material is set within the quasi-static loading range, and the strain step size of the metal material is set to 10 -5 And the strain rate of the metal material is set to 10 -3 / s; the quasi-static loading range is 10 -4 ~10 -1 s -1 .

[0016] Furthermore, the step (2) specifically includes the following sub-steps:

[0017] (2.1) Calculating the amorphous phase constitutive model and related parameters of the KM model using the amorphous phase constitutive model, the KM theoretical model, and the material parameters of the metal material obtained in step (1);

[0018] (2.2) By adjusting the sensitivity coefficient m and the grain strain gradient parameter SGGB in the dynamic crystal phase constitutive model, the trends of the elastic and yield stages in the simulated true stress-strain curves of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression are made consistent with the trends of the elastic and yield stages in the experimentally characterized true stress-strain curves of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression.

[0019] (2.3) By adjusting the number of dislocations N or the dislocation slip length coefficient Lamdan in the back stress model, and adjusting the calculable parameter C1, the parameter C2 representing the dislocation multiplication rate, and the parameter C3 representing the dislocation annihilation rate in the KM model, the trend of the strengthening stage in the simulated true stress-strain curve of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression is made consistent with the trend of the strengthening stage in the true stress-strain curve of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression obtained from experimental characterization;

[0020] (2.4) By adjusting the Weber modulus or microcrack density in the microcrack failure model parameters, the failure stage trends in the simulated true stress-strain curves of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression are made consistent with the failure stage trends in the experimentally characterized true stress-strain curves of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression;

[0021] (2.5) Repeat steps (2.1) to (2.4) so ​​that the simulated true stress-strain curve of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material is consistent with the true stress-strain curve of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material obtained by experimental characterization, and determine all the final model parameters.

[0022] The beneficial effects of the present invention are: establishing a high-temperature constitutive model that can comprehensively consider the microstructural characteristics, predicting the crystal-amorphous dual-phase metal material and its high-temperature mechanical properties, and providing a theoretical basis for the changes in the high-temperature tensile / compression properties of the crystal-amorphous dual-phase metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flowchart of a method for calculating the high-temperature elastic-plastic constitutive behavior and strength-toughness properties of crystalline-amorphous dual-phase metals based on deformation mechanism and microstructural composition;

[0024] Figure 2 A comparison chart showing the predictions and experiments of a computational high-temperature elastic-plastic constitutive model for a crystalline-amorphous dual-phase metal based on deformation mechanism and microstructural composition at 450K.

[0025] Figure 3 This is a comparison chart between the prediction and experiment of a computational high-temperature elastic-plastic constitutive model of crystal-amorphous dual-phase metal based on deformation mechanism and microstructural composition at 500K. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention, rather than to represent all embodiments. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0027] The present invention is based on the framework of elastic-plastic theory, takes into account the deformation mechanism and microstructural composition, and realizes numerical calculations through MATLAB to simulate and predict the high-temperature uniaxial tensile / compression elastic-plastic constitutive behavior and toughness characteristics of crystal-amorphous dual-phase metals. Taking into account the microstructural characteristics such as the internal grain size of the metal, the evolution of dislocation density and the generation and evolution of microcracks, and the evolution of the amorphous volume fraction with temperature, the high-temperature uniaxial tensile / compression elastic-plastic constitutive behavior and toughness characteristics of these metal materials whose microstructures are composed of a dual phase of crystal phase and amorphous phase are simulated and predicted. In the experiments of preparing crystal-amorphous dual-phase metal materials and measuring their high-temperature mechanical properties, a theoretical basis is provided for the changes in the high-temperature tensile / compression properties of crystal-amorphous dual-phase metals, and theoretical guidance can be provided for how to improve the high-temperature mechanical properties of crystal-amorphous dual-phase metals.

[0028] Example 1

[0029] like Figure 1 As shown, the present invention provides a method for calculating the high-temperature elastic-plastic constitutive behavior and toughness characteristics of crystal-amorphous dual-phase metal based on deformation mechanism and microstructure composition, comprising the following steps:

[0030] (1) The material parameters and structural information of the metal material are obtained through experimental characterization, the true stress-strain curve of the high-temperature uniaxial tension / compression of the crystalline-amorphous dual-phase metal material is obtained, and the initial conditions of the metal material are set.

[0031] The step (1) specifically includes the following sub-steps:

[0032] (1.1) obtaining material parameters and structural information of the metal material through experimental characterization, wherein the material parameters include the elastic modulus, Poisson's ratio, Burger vector, Taylor parameter, and yield strength of coarse grains of the metal material, and the structural information includes grain size, amorphous phase scale, and amorphous phase volume fraction;

[0033] The metal material is a crystalline-amorphous dual-phase metal material;

[0034] The high-temperature engineering stress-strain curve of crystalline-amorphous dual-phase metal materials was obtained through experimental characterization.

[0035] (1.2) Converting the high-temperature engineering stress-strain curve of the crystalline-amorphous dual-phase metal material into the real stress-strain curve of the high-temperature uniaxial tension / compression of the crystalline-amorphous dual-phase metal material obtained by experimental characterization;

[0036] Then, the shear modulus and bulk modulus of the metal material are calculated based on the elastic modulus and Poisson's ratio; and the temperature-dependent changes in the size of the discrete metal material's microstructure and the volume fraction of the discrete metal material's microstructure measured experimentally are fitted with a continuous function curve to obtain the relationship curve between the size of the microstructure in the metal material and the temperature, as well as the relationship curve between the volume fraction of the microstructure in the metal material and the temperature.

[0037] (1.3) Set the initial conditions of the metal material: the true elastic stress, true elastic strain, true plastic stress and true plastic strain of the metal material are all set to 0, the dislocation density of the metal material is normalized and set to 1, the strain loading of the metal material is set within the quasi-static loading range, and the strain step size of the metal material is set to 10 -5 And the strain rate of the metal material is set to 10 -3 / s; the quasi-static loading range is 10 -4 ~10 -1 s -1 .

[0038] (2) By adjusting the sensitivity coefficient m and grain strain gradient parameter SGGB in the dynamic crystal phase constitutive model, the number of dislocations N or dislocation slip length coefficient Lamdan in the back stress model, and the Weber modulus or microcrack density in the microcrack failure model parameters, the real stress-strain curves of the elastic, yield, strengthening, and failure stages of high-temperature uniaxial tension / compression of crystal-amorphous dual-phase metal materials are simulated and fitted, and all the final model parameters are determined.

[0039] The step (2) specifically includes the following sub-steps:

[0040] (2.1) The amorphous phase constitutive model, the KM theoretical model and the material parameters of the metal material obtained in step (1) are used to calculate the relevant parameters of the amorphous phase constitutive model and the KM model.

[0041] (2.2) By adjusting the sensitivity coefficient m and the grain strain gradient parameter SGGB in the dynamic crystal phase constitutive model, the trends of the elastic and yield stages in the simulated true stress-strain curve of the crystal-amorphous dual-phase metal material under high-temperature uniaxial tension / compression are made consistent with the trends of the elastic and yield stages in the true stress-strain curve of the crystal-amorphous dual-phase metal material under high-temperature uniaxial tension / compression obtained by experimental characterization.

[0042] (2.3) By adjusting the number of dislocations N or the dislocation slip length coefficient Lamdan in the back stress model, and adjusting the calculable parameter C1, the parameter C2 representing the dislocation multiplication rate, and the parameter C3 representing the dislocation annihilation rate in the KM model, the trend of the strengthening stage in the true stress-strain curve of the high-temperature uniaxial tension / compression of the simulated crystal-amorphous dual-phase metal material is consistent with the trend of the strengthening stage in the true stress-strain curve of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material obtained by experimental characterization.

[0043] (2.4) By adjusting the Weber modulus or microcrack density in the microcrack failure model parameters, the trends of the failure stage in the simulated true stress-strain curve of the crystalline-amorphous dual-phase metal material under high-temperature uniaxial tension / compression are made consistent with the trends of the failure stage in the true stress-strain curve of the crystalline-amorphous dual-phase metal material under high-temperature uniaxial tension / compression obtained by experimental characterization.

[0044] (2.5) Repeat steps (2.1) to (2.4) so ​​that the simulated true stress-strain curve of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material is consistent with the true stress-strain curve of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material obtained by experimental characterization, and determine all the final model parameters.

[0045] (3) Based on the material parameters and model parameters determined in steps (1) and (2), the grain size and ambient temperature are changed to predict the effect of grain size on the high-temperature tensile / compressive elastoplastic constitutive behavior and toughness properties of the material when the amorphous phase size is uniformly distributed.

[0046] This paper introduces the amorphous constitutive model and the KM dislocation model within the framework of elastic-plastic theory, linking the mechanical behavior of a material with its microstructure. This approach can describe the differences in mechanical properties of the same material with different microstructures. Furthermore, a numerical calculation method was designed using Matlab software to simulate the high-temperature uniaxial tension / compression mechanical properties of crystalline-amorphous dual-phase metals.

[0047] Figure 2 A comparison chart showing the predictions and experiments of a computational high-temperature elastic-plastic constitutive model for a crystalline-amorphous dual-phase metal based on deformation mechanism and microstructural composition at 450K. Figure 3 This is a comparison chart between the prediction and experiment of a computational high-temperature elastic-plastic constitutive model of crystal-amorphous dual-phase metal based on deformation mechanism and microstructural composition at 500K.

[0048] Figure 2 The black curve in the middle is the constitutive curve predicted by a computational crystalline-amorphous dual-phase metal high-temperature elastic-plastic constitutive model based on deformation mechanism and microstructural composition at 450K. The purple curve is the constitutive curve measured by tensile test at 450K. Figure 3 The black curve is the constitutive curve predicted by a computational crystal-amorphous dual-phase metal high-temperature elastic-plastic constitutive model based on deformation mechanism and microstructural composition at 500K. The blue curve is the constitutive curve measured by tensile test at 500K. Figure 2 and Figure 3 It is proved that the curve predicted by the model is consistent with the constitutive curve obtained from the experiment.

[0049] 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 in the scope of protection of the present invention.

Claims

1. A method for calculating the high-temperature elastic-plastic constitutive behavior and toughness properties of crystalline-amorphous dual-phase metals based on deformation mechanism and microstructural composition, characterized in that: The following steps are involved: (1) Obtain the material parameters and structural information of the metal material through experimental characterization, obtain the true stress-strain curve of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material, and set the initial conditions of the metal material; (2) By adjusting the sensitivity coefficient m and the grain strain gradient parameter SGGB in the dynamic crystal phase constitutive model, the number of dislocations N or the dislocation slip length coefficient Lamdan in the back stress model, and the Weber modulus or microcrack density in the microcrack failure model parameters, the real stress-strain curves of the elastic, yield, strengthening, and failure stages of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material are simulated and fitted, and all the final model parameters are determined; (3) Based on the material parameters and model parameters determined in steps (1) and (2), the grain size and ambient temperature are changed to predict the effect of grain size on the high-temperature tensile / compressive elastoplastic constitutive behavior and toughness properties of the material when the amorphous phase size is uniformly distributed.

2. The method for calculating the high-temperature elastic-plastic constitutive behavior and toughness characteristics of crystalline-amorphous dual-phase metals based on deformation mechanism and microstructure composition according to claim 1, characterized in that: The step (1) specifically includes the following sub-steps: (1.1) obtaining material parameters and structural information of the metal material through experimental characterization, wherein the material parameters include the elastic modulus, Poisson's ratio, Burger vector, Taylor parameter, and yield strength of coarse grains of the metal material, and the structural information includes grain size, amorphous phase scale, and amorphous phase volume fraction; The metal material is a crystalline-amorphous dual-phase metal material; The high-temperature engineering stress-strain curve of crystalline-amorphous dual-phase metal materials was obtained through experimental characterization; (1.2) Converting the high-temperature engineering stress-strain curve of the crystalline-amorphous dual-phase metal material into the real stress-strain curve of the high-temperature uniaxial tension / compression of the crystalline-amorphous dual-phase metal material obtained by experimental characterization; Then, the shear modulus and bulk modulus of the metal material are calculated based on the elastic modulus and Poisson's ratio. The temperature-dependent changes in the size and volume fraction of the discrete metal material microstructures measured experimentally are then fitted with a continuous function curve to obtain the relationship curves between the size and temperature changes of the microstructures in the metal material and the relationship curves between the volume fraction and temperature changes of the microstructures in the metal material. (1.3) Set the initial conditions of the metal material: the true elastic stress, true elastic strain, true plastic stress and true plastic strain of the metal material are all set to 0, the dislocation density of the metal material is normalized and set to 1, the strain loading of the metal material is set within the quasi-static loading range, and the strain step size of the metal material is set to 10 -5 And the strain rate of the metal material is set to 10 -3 / s; the quasi-static loading range is 10 -4 ~10 -1 s -1 .

3. The method for calculating the high-temperature elastic-plastic constitutive behavior and toughness characteristics of a crystalline-amorphous dual-phase metal based on deformation mechanism and microstructure composition according to claim 2, characterized in that: The step (2) specifically includes the following sub-steps: (2.1) Calculating the amorphous phase constitutive model and related parameters of the KM model using the amorphous phase constitutive model, the KM theoretical model, and the material parameters of the metal material obtained in step (1); (2.2) By adjusting the sensitivity coefficient m and the grain strain gradient parameter SGGB in the dynamic crystal phase constitutive model, the trends of the elastic and yield stages in the simulated true stress-strain curves of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression are made consistent with the trends of the elastic and yield stages in the experimentally characterized true stress-strain curves of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression. (2.3) By adjusting the number of dislocations N or the dislocation slip length coefficient Lamdan in the back stress model, and adjusting the calculable parameter C1, the parameter C2 representing the dislocation multiplication rate, and the parameter C3 representing the dislocation annihilation rate in the KM model, the trend of the strengthening stage in the simulated true stress-strain curve of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression is made consistent with the trend of the strengthening stage in the true stress-strain curve of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression obtained from experimental characterization; (2.4) By adjusting the Weber modulus or microcrack density in the microcrack failure model parameters, the failure stage trends in the simulated true stress-strain curves of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression are made consistent with the failure stage trends in the experimentally characterized true stress-strain curves of the crystalline-amorphous dual-phase metal under high-temperature uniaxial tension / compression; (2.5) Repeat steps (2.1) to (2.4) so ​​that the simulated true stress-strain curve of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material is consistent with the true stress-strain curve of the high-temperature uniaxial tension / compression of the crystal-amorphous dual-phase metal material obtained by experimental characterization, and determine all the final model parameters.

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