Fe-Mn-Si alloy component design method based on DIMT chemical driving force and product

Abstract

The invention discloses a DIMT chemical driving force-based Fe-Mn-Si alloy component design method and a product, and belongs to the technical field of alloy material design and microstructure optimization. The method comprises the following steps: establishing a basic chemical driving force model of the Fe-Mn alloy; according to the basic chemical driving force model, a DIMT chemical driving force model of the Fe-Mn-Si series alloy is established; a DIMT chemical driving force model of the Fe-Mn-Si series alloy is optimized; based on the optimized model, the austenite stability of different alloy elements is evaluated through chemical driving force energy indexes, and alloy components are designed; based on the designed alloy components, the alloy mechanical property and the austenite volume fraction are measured, and the consistency of the influence of the alloy components on the austenite stability and mechanical property and the model prediction result is verified. According to the method, efficient and accurate design of Fe-Mn-Si alloy components is achieved, the research and development period is shortened, the cost is reduced, and the consistency of theoretical prediction and experimental results of component design is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of Fe-Mn-Si alloy material design and microstructure optimization, and particularly relates to a Fe-Mn-Si alloy composition design method based on DIMT chemical driving force and a product. BACKGROUND

[0002] Fe-Mn-Si alloy, as an important structural material, has a wide application prospect in the fields of automobile manufacturing, engineering machinery, aerospace, etc. due to its excellent strength, plasticity and forming performance. In recent years, with the increasing demand for lightweight and high safety of materials, the composition optimization and performance regulation of the alloy have become a research hotspot in the field of materials science.

[0003] The composition design of the alloy is a key link to determine its microstructure and macroscopic performance, and directly affects the phase transition behavior, mechanical properties and service life of the material. The traditional composition design of Fe-Mn-Si alloy relies on experience accumulation and a large number of orthogonal experiments, and has problems such as long research and development cycle, high cost, and difficulty in accurately regulating the composition-performance relationship. Especially when multiple alloying elements (such as Si) are introduced into the alloy, the interaction between elements will significantly change the thermodynamic equilibrium state of the alloy, and the traditional method is difficult to accurately describe the phase transition driving force and organization evolution law under the multi-element system.

[0004] The chemical driving force, as a key parameter representing the thermodynamic trend of alloy phase transition, is of great significance to guide the alloy composition design. The DIMT (Deformation induced Martensitic Transformation) chemical driving force model can effectively reflect the influence mechanism of alloy elements on the phase transition behavior by quantifying the energy change in the phase transition process. However, existing DIMT models are mostly established for simple binary or ternary alloy systems, and do not fully consider the special role of Si element in Fe-Mn matrix and the regulation law of C element interaction with other elements on the phase transition driving force. At the same time, the thermodynamic coefficients used in the traditional model are mostly based on the ideal solution assumption, which deviates from the actual crystal sublattice structure of the alloy, resulting in a large error between the theoretical prediction of composition design and the experimental results.

[0005] Therefore, developing a DIMT chemical driving force analysis method that can accurately incorporate the influence of Si element, consider the interaction of C element, and optimize the thermodynamic parameters based on the crystal sublattice model, has important theoretical value and practical significance for realizing the efficient design of Fe-Mn-Si alloy composition and the accurate regulation of performance. SUMMARY

[0006] The present application aims to overcome the defects in the existing Fe-Mn-Si alloy composition design method, such as dependence on experience and a large number of experiments, long research and development cycle, high cost, and the DIMT chemical driving force model not fully considering the effects of Si element, C element interaction and crystal sublattice structure, and provides an Fe-Mn-Si alloy composition design method based on DIMT chemical driving force and a product, so as to realize efficient and accurate design of Fe-Mn-Si alloy composition, shorten the research and development cycle, reduce the cost, and improve the consistency of theoretical prediction and experimental results of composition design.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0008] According to the first aspect of the technical solutions of the present application, an Fe-Mn-Si alloy composition design method based on DIMT chemical driving force is provided, wherein the method comprises the following steps:

[0009] (1) establishing a basic chemical driving force model of Fe-Mn alloy;

[0010] (2) establishing a DIMT chemical driving force model of Fe-Mn-Si alloy according to the basic chemical driving force model;

[0011] (3) optimizing the DIMT chemical driving force model of Fe-Mn-Si alloy;

[0012] (4) based on the optimized DIMT chemical driving force model, evaluating the austenite stability of different alloy elements through the chemical driving force energy index, and designing the alloy composition;

[0013] (5) based on the designed alloy composition, determining the mechanical properties and austenite volume fraction of the alloy through experiments, verifying the consistency of the influence of the alloy composition on the austenite stability and mechanical properties with the model prediction results; if consistent, output the alloy composition; otherwise, return to step (3) to further optimize the model until the results are consistent.

[0014] Further, in step (1), the basic chemical driving force model of Fe-Mn alloy includes the thermodynamic parameters and interaction relationships of each main element in the alloy.

[0015] Further, in step (1), the basic chemical driving force model of Fe-Mn alloy is:

[0016] wherein, represents the chemical driving force of Fe-Mn alloy, represents the energy of pure Fe element from fcc phase to hcp phase transition, This represents the energy required for the transformation of pure Mn element from the fcc phase to the hcp phase. It is the excess free energy coefficient of the Fe / Mn binary system interaction, y Fe y Mn This represents the mole fraction of Fe and Mn. It is the Mohr Gibbs energy caused by the magnetic state of the phase.

[0017] Furthermore, in step (1), in the basic chemical driving force model of the Fe-Mn alloy:

[0018] The energy required for the transformation of pure elements Fe and Mn from the fcc phase to the hcp phase is:

[0019] The excess free energy coefficient of the Fe and Mn interaction is:

[0020] The molar Gibbs energy caused by the magnetic state of the phase is:

[0021] in, It is the magnetic contribution in the hcp phase. It is the magnetic contribution in the fcc phase.

[0022] Furthermore, in step (2), Si element is added, taking into full account the thermodynamic properties of Si element itself, as well as the interaction between C, Si elements and Fe, Mn elements, to construct the Fe-Mn-Si alloy DIMT chemical driving force model.

[0023] Furthermore, in step (2), the chemical driving force model of the Fe-Mn-Si alloy DIM-T constructed after considering C and Si elements is as follows:

[0024]

[0025] in, This indicates the chemical driving force of Fe-Mn-Si alloys. This represents the energy required for the transformation of pure Fe from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure Mn element from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure Si from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure carbon from the fcc phase to the hcp phase. It is the excess free energy coefficient of the Fe / Mn binary system based on their interaction. It is the excess free energy coefficient of the Fe-Si binary system interacting with each other. It is the excess free energy coefficient of the interaction between the Mn and Si binary system. It is the excess free energy coefficient of the Fe / C binary system interacting with each other. It is the excess free energy coefficient of the interaction between the Mn and C binary system. It is the Mohr Gibbs energy caused by the magnetic state of the phase, y Fe y Mn y Si y C This indicates the mole fraction of Fe, Mn, Si, and C.

[0026] Furthermore, in the DIMT chemical driving force model of Fe-Mn-Si alloys constructed after considering C and Si elements:

[0027] The energy required for the transformation of pure elements C and Si from the fcc phase to the hcp phase is:

[0028] The excess free energy coefficients of the interactions between C, Si, Fe, and Mn elements are:

[0029] The molar Gibbs energy caused by the magnetic state of the phase is:

[0030] in, It is the magnetic contribution in the hcp phase. It is the magnetic contribution in the fcc phase.

[0031] Furthermore, in step (3), based on the crystal sublattice model, the coefficients of the constructed Fe-Mn-Si alloy DIMT chemical driving force model are precisely modified through thermodynamic calculations to improve the key calculation coefficients of the model and achieve model optimization.

[0032] Further, in step (3), based on the crystal sublattice model and thermodynamic calculations, the energy occupied by each element in the fcc phase and hcp phase is calculated respectively, and the energy difference of each element from the fcc phase to the hcp phase is calculated. The key calculation coefficients of the Fe-Mn-Si alloy DIMT chemical driving force model are optimized by linear fitting.

[0033] Furthermore, in step (3), after optimization using the crystal sublattice model, the energy required for the transformation of pure elements Fe and Mn from the fcc phase to the hcp phase is:

[0034] Furthermore, in step (4), the chemical driving force energy index is a thermodynamic energy parameter related to austenite stability calculated by the optimized DI MT chemical driving force model. This parameter is used to compare the stability of austenite under different alloy element combinations, thereby guiding the alloy composition design and improving the mechanical properties of Fe-Mn-Si alloys.

[0035] Furthermore, in step (4), the chemical driving force energy index for evaluating austenite stability is the energy parameter calculated using the optimized Fe-Mn-Si alloy chemical driving force model.

[0036] Furthermore, in step (4), the energy parameters calculated using the chemical driving force model are... Comparing the stability of austenite under different alloy element combinations, when energy parameters When the energy parameter is equal to or below -350J, the higher the energy parameter, the stronger the austenite stability, the stronger the TRIP effect, and the higher the alloy strength and plasticity. Above -350J, the higher the energy parameter, the higher the austenite stability, the easier it is to undergo the TWIP effect, the slightly lower the strength, and the significantly improved plasticity. Based on the required target mechanical properties, the optimal combination of alloying elements is output by comparing the magnitude of the energy parameter.

[0037] Furthermore, in step (5), the experiment includes alloy preparation experiment, mechanical property testing experiment and XRD measurement of austenite content, and the mechanical properties include strength and plasticity.

[0038] According to a second aspect of the present invention, an Fe-Mn-Si alloy is provided, wherein the Fe-Mn-Si alloy is obtained by composition design based on the above-mentioned DIMT chemical driving force composition design method.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] First, this invention establishes and optimizes the DIMT chemical driving force model for Fe-Mn-Si alloys, fully considering the role of Si and the interaction between C and other elements. Furthermore, it modifies the correlation coefficient based on the crystal sublattice model, making the model more consistent with the actual crystal structure and thermodynamic behavior of the alloy, thereby improving the accuracy of the model.

[0041] Secondly, by using the method of this invention to design the composition of Fe-Mn-Si alloys, the stability of austenite can be evaluated through the chemical driving force energy index obtained by model calculation, thereby guiding the alloy composition design, reducing the reliance on experience and a large number of orthogonal experiments, shortening the research and development cycle, and reducing the research and development cost.

[0042] Third, through experimental verification steps, this invention can quickly verify the rationality of the alloy composition design and predict the mechanical properties of the alloy, providing a reliable theoretical basis and practical guidance for the composition optimization and performance control of Fe-Mn-Si alloys, which is conducive to promoting the better application of this alloy system in various fields. Attached Figure Description

[0043] Figure 1 The diagram shown is an overall flowchart of a Fe-Mn-Si alloy composition design method based on DIMT chemical driving force in an embodiment of the present invention.

[0044] Figure 2 The figure shows the chemical driving force of DIMT under different alloy compositions designed in the examples.

[0045] Figure 3 The figures show the mechanical properties of Fe-Mn-Si alloys with two different alloy compositions in the examples. Detailed Implementation

[0046] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered in isolation, but can be combined with each other to achieve better technical effects.

[0047] This invention discloses a method and product for designing the composition of Fe-Mn-Si alloys based on DIMT (Digital-Induced Transformation) chemical driving force. This method constructs a composition design system with chemical driving force as the core guiding indicator. First, a theoretical model of the chemical driving force of basic Fe-Mn alloys is established to clarify the energy mechanism during the alloy phase transformation process. Then, based on this initial model, combined with the thermodynamic regulation law of Si element on the alloy phase transformation, a DIMT chemical driving force prediction model specific to Fe-Mn-Si alloys is constructed. The model is then optimized using thermodynamic calculation software and a crystal sublattice model to improve its accuracy and applicability. Based on the optimized model, the stability of the austenite phase under different alloy element ratios is systematically evaluated using the chemical driving force energy index as the core criterion, forming a scientifically controllable method for designing the composition of Fe-Mn-Si alloys. Finally, based on the designed alloy composition, the mechanical properties and austenite volume fraction are experimentally measured to rapidly verify the influence of alloy composition on austenite stability, thus providing a theoretical basis for the alloy composition design of Fe-Mn-Si alloys. This method can effectively utilize the regulatory effect of chemical driving force on performance, help improve the mechanical properties of Fe-Mn-Si alloys, and accelerate the experimental process, saving time and cost in the research and development of new materials.

[0048] Specifically, the technical solution of this invention first provides a method for designing the composition of Fe-Mn-Si alloys based on DIMT chemical driving force, such as... Figure 1 As shown, it includes the following steps:

[0049] (1) Establish a chemical driving force model for basic Fe-Mn alloys: Based on the regular solution model, construct a chemical driving force model applicable to basic Fe-Mn alloys. This model includes the thermodynamic parameters and interaction relationships of the main elements in the alloy.

[0050] (2) Establish the DIMT chemical driving force model of Fe-Mn-Si alloy: Based on the basic model established in step (1), fully consider the thermodynamic properties of C and Si elements themselves, as well as the interaction between C and Si elements and Fe, Mn and other elements, and establish the DIMT chemical driving force model of Fe-Mn-Si alloy.

[0051] (3) Optimize the DIMT chemical driving force model of Fe-Mn-Si alloy: Based on the basic model established in step (1), the key coefficients of the model are optimized by thermodynamic calculation based on the crystal sublattice model to better fit the actual crystal structure and thermodynamic behavior of the alloy.

[0052] (4) Calculate chemical driving force and design alloy composition: Based on the optimized DIMT chemical driving force model of Fe-Mn-Si alloy, design different alloy compositions, evaluate the austenite stability of different alloying elements by chemical driving force energy index. The energy index is the thermodynamic energy parameter related to austenite stability calculated by the optimized DIMT chemical driving force model. Use this parameter to compare the austenite stability under different alloying element combinations, and then guide the alloy composition design.

[0053] (5) Verify the alloy composition design and iteratively optimize the model coefficients: Based on the designed alloy composition, the mechanical properties and austenite content of the alloy are determined by experiment, the actual DIMT chemical driving force is calculated to verify the influence of the alloy composition on the stability of austenite, and the mechanical properties of Fe-Mn-Si alloys are predicted, providing a theoretical basis for the alloy composition design of Fe-Mn-Si alloys; wherein, the experiment includes alloy preparation experiment, mechanical property testing experiment and XRD measurement of austenite content experiment, and the mechanical properties include strength, plasticity, etc.

[0054] Example

[0055] Taking an Fe-Mn-Si alloy with a composition range of C: 0.1–0.9 wt.%, Mn: 5–24 wt.%, Si: 0–8 wt.%, and the balance being Fe as an example, a Fe-Mn-Si alloy composition design method based on DIMT chemical driving force includes the following steps:

[0056] 1. Based on the regular solution model, a chemical driving force model suitable for basic Fe-Mn alloys is constructed. This model includes the thermodynamic parameters and interaction relationships of the main elements in the alloy. The calculation formula is shown below:

[0057]

[0058] Table 1 below shows the key coefficients of the chemical driving force model for basic Fe-Mn alloys:

[0059] Table 1 Key coefficients of the DIMT chemical driving force model for basic Fe-Mn alloys

[0060]

[0061]

[0062] in, This indicates the chemical driving force of Fe-Mn-Si alloys. This represents the energy required for the transformation of pure Fe from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure Mn element from the fcc phase to the hcp phase. It is the excess free energy coefficient of the Fe / Mn binary system interaction, y Fe y Mn This represents the mole fraction of Fe and Mn. It is the Mohr Gibbs energy caused by the magnetic state of the phase. It is the magnetic contribution in the hcp phase. It is the magnetic contribution in the fcc phase. It's the NieR temperature. It is the magnetic moment, μ B It is the Bohr magneton, R is the gas constant, T is the absolute temperature, P is the magnetic order parameter, and τ and D are normalization parameters.

[0063] 2. Taking full account of the thermodynamic properties of Si and the interactions between C and elements such as Fe and Mn, a DIMT chemical driving force model for Fe-Mn-Si alloys was constructed based on the original model, using a thermodynamic database. The model calculations are as follows:

[0064]

[0065] 3. Based on the crystal sublattice model and thermodynamic calculations, the energies of pure Fe and pure Mn in the fcc and hcp phases, respectively, were calculated. The calculation results are shown in Table 2.

[0066] Table 2. Energy of pure Fe and pure Mn in the fcc and hcp phases at different temperatures.

[0067]

[0068] Then, by linearly fitting the energy difference between the phase transitions of pure Fe and pure Mn, The relationship with temperature T was investigated to iteratively optimize the key coefficients of the DIMT chemical driving force model for Fe-Mn-Si alloys, further refining the model to better reflect the actual crystal structure and thermodynamic behavior of the alloys. The optimized key coefficients of the DIMT chemical driving force model for Fe-Mn-Si alloys are shown in Table 3.

[0069] Table 3 Key coefficients of the optimized DIMT chemical driving force model for Fe-Mn-Si alloys

[0070]

[0071] in, This indicates the chemical driving force of Fe-Mn-Si alloys. This represents the energy required for the transformation of pure Fe from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure Mn element from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure Si from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure carbon from the fcc phase to the hcp phase. It is the excess free energy coefficient of the Fe / Mn binary system based on their interaction. It is the excess free energy coefficient of the Fe-Si binary system interacting with each other. It is the excess free energy coefficient of the interaction between the Mn and Si binary system. It is the excess free energy coefficient of the Fe / C binary system interacting with each other. It is the excess free energy coefficient of the interaction between the Mn and C binary system. It is the Mohr Gibbs energy caused by the magnetic state of the phase, y Fe y Mn y Si y C This represents the mole fraction of Fe, Mn, Si, and C. It is the magnetic contribution in the hcp phase. It is the magnetic contribution in the fcc phase. It's the NieR temperature. It is the magnetic moment, μ B It is the Bohr magneton, R is the gas constant, T is the absolute temperature, P is the magnetic order parameter, and τ and D are normalization parameters.

[0072] 4. Based on the optimized DIMT chemical driving force model for Fe-Mn-Si alloys, the austenite stability of different alloying elements is evaluated using the chemical driving force energy index, such as... Figure 2 The figure shows the variation of DIMT chemical driving force under different alloy compositions. With increasing Mn and C content, the chemical driving force increases, and austenite stability is enhanced. The effect of Si on austenite stability is related to Mn. At low Mn content, with increasing Si content, the DIMT chemical driving force first increases and then decreases, and austenite stability first increases and then decreases. At high Mn content, adding Si reduces austenite stability. Taking Fe-12Mn-xSi-0.4C wt.% as an example, the variation of DIMT chemical driving force under different Si compositions was calculated, and the results are shown in Table 4.

[0073] Table 4 Chemical driving forces of DIMT under different Si contents

[0074] 0 wt. % Si 2 wt. % Si 4 wt. % Si 6 wt. % Si 8 wt. % Si 10 wt. % Si -306.287J -280.059J -259.823J -257.244J -273.903J -308.069J

[0075] The calculation results show that when the Mn content is low, the addition of a small amount of Si increases the chemical driving force of DIMT in Fe-Mn-Si alloys and enhances the stability of austenite. Therefore, it is predicted that the mechanical properties of Fe-Mn-Si alloys will be improved after adding a small amount of Si.

[0076] 5. Based on previous calculations of the Fe-Mn-Si system model for different Mn, Si, and C contents using the DIMT chemical driving force, two Fe-Mn-Si alloys with different compositions, Fe-5Mn-0.2C wt.% and Fe-5Mn-1.5Si-0.2C wt.%, were smelted. The chemical driving force energy parameters for both alloy compositions were calculated using the model. The J values ​​are -636.833 J and -570.475 J, respectively. Based on the comparison of chemical driving force energy parameters, the austenite stability of the Fe-5Mn-1.5Si-0.2C wt.% alloy is stronger than that of Fe-5Mn-0.2C wt.%, and because the chemical driving force energy parameter is lower than -350 J, its strength and plasticity are also superior to Fe-5Mn-0.2C wt.%. For these two alloys, appropriate heat treatment processes were designed and implemented, and the austenite content and tensile curves of the two alloys at room temperature were obtained, as shown below. Figure 3As shown, the Fe-5Mn-1.5Si-0.2C wt.% alloy at room temperature has a higher austenite content, and its tensile strength and elongation both exceed those of Fe-5Mn-0.2C wt.%, consistent with the calculation results of the Fe-Mn-Si system model for DIMT chemical driving force. This result confirms that adding a small amount of Si can improve the stability of austenite when the Mn content is low, thereby improving the comprehensive mechanical properties of the Fe-Mn-Si system alloy. It also proves the accuracy of the DIMT chemical driving force model for the Fe-Mn-Si system alloy. If the experimentally determined austenite content and mechanical property indicators are inconsistent with the model prediction results, it is necessary to return to step (2) to further optimize the model coefficients and recalculate the chemical driving force until it is consistent with the experimental results. Then, according to the model calculation, different alloy compositions are input, the chemical driving force energy parameters are compared, and the alloy composition corresponding to the desired mechanical properties is output.

[0077] In summary, the Fe-Mn-Si alloy composition design method based on DIMT chemical driving force of this invention can accurately and efficiently design the composition of Fe-Mn-Si alloys. By establishing and optimizing the DIMT chemical driving force model, the effects of C and Si elements, the interactions between C and Si elements and Fe and Mn, and the influence of crystal sublattice structure are fully considered. The composition design is guided by evaluating austenite stability using the chemical driving force energy index, reducing reliance on experience and extensive experiments, shortening the R&D cycle, and lowering R&D costs. Simultaneously, the experimental verification stage can verify the rationality of the composition design and predict mechanical properties, providing a reliable theoretical basis and practical guidance for the composition optimization and performance control of this alloy system. It has significant application value in materials research and development and other related technical fields. Furthermore, any equivalent transformations made using the content of this specification, or any direct or indirect applications in related technical fields, as long as they do not depart from the spirit and scope of this invention, are covered within the protection scope of this invention.

Claims

1. A method for designing the composition of Fe-Mn-Si alloys based on DIMT chemical driving force, characterized in that, The method includes the following steps: (1) Establish a basic chemical driving force model for Fe-Mn alloys; (2) Based on the aforementioned basic chemical driving force model, establish a DIMT chemical driving force model for Fe-Mn-Si alloys; (3) Optimize the DIMT chemical driving force model for Fe-Mn-Si alloys; (4) Based on the optimized DIMT chemical driving force model, the austenite stability of different alloying elements is evaluated by the chemical driving force energy index, and the alloy composition is designed. (5) Based on the designed alloy composition, determine the mechanical properties and austenite volume fraction of the alloy, and verify the consistency between the influence of the alloy composition on the stability and mechanical properties of austenite and the model prediction results: if consistent, output the alloy composition; otherwise, return to step (3) to further optimize the model until the results are consistent.

2. The Fe-Mn-Si alloy composition design method according to claim 1, characterized in that, In step (1), the basic chemical driving force model of the Fe-Mn alloy includes the thermodynamic parameters and interaction relationships of the main elements in the alloy.

3. The Fe-Mn-Si alloy composition design method according to claim 1, characterized in that, In step (2), Si element is added, taking into full account the thermodynamic properties of Si element itself, as well as the interaction between C, Si elements and Fe, Mn elements, to construct the DIMT chemical driving force model of Fe-Mn-Si alloy.

4. The Fe-Mn-Si alloy composition design method according to claim 3, characterized in that, In step (2), the chemical driving force model for the Fe-Mn-Si alloy DIMT, constructed after considering C and Si elements, is as follows: in, This indicates the chemical driving force of Fe-Mn-Si alloys. This represents the energy required for the transformation of pure Fe from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure Mn element from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure Si from the fcc phase to the hcp phase. This represents the energy required for the transformation of pure carbon from the fcc phase to the hcp phase. It is the excess free energy coefficient of the Fe / Mn binary system based on their interaction. It is the excess free energy coefficient of the Fe-Si binary system interacting with each other. It is the excess free energy coefficient of the interaction between the Mn and Si binary system. It is the excess free energy coefficient of the Fe / C binary system interacting with each other. It is the excess free energy coefficient of the interaction between the Mn and C binary system. It is the Mohr Gibbs energy caused by the magnetic state of the phase, y Fe y Mn y Si y C This indicates the mole fraction of Fe, Mn, Si, and C.

5. The Fe-Mn-Si alloy composition design method according to claim 4, characterized in that, In the DIMT chemical driving force model of Fe-Mn-Si alloys constructed after considering C and Si elements: The energy required for the transformation of pure elements C and Si from the fcc phase to the hcp phase is: The excess free energy coefficients of the interactions between C, Si, Fe, and Mn elements are: The molar Gibbs energy caused by the magnetic state of the phase is: in, It is the magnetic contribution in the hcp phase. It is the magnetic contribution in the fcc phase.

6. The Fe-Mn-Si alloy composition design method according to claim 1, characterized in that, In step (3), based on the crystal sublattice model, the coefficients of the constructed Fe-Mn-Si alloy DIMT chemical driving force model are precisely modified through thermodynamic calculations to improve the key calculation coefficients of the model and achieve model optimization.

7. The Fe-Mn-Si alloy composition design method according to claim 6, characterized in that, In step (3), based on the crystal sublattice model and thermodynamic calculations, the energy occupied by each element in the fcc phase and hcp phase is calculated respectively, and the energy difference of each element from the fcc phase to the hcp phase is calculated. The key calculation coefficients of the Fe-Mn-Si alloy DIMT chemical driving force model are optimized by linear fitting.

8. The Fe-Mn-Si alloy composition design method according to claim 7, characterized in that, In step (3), after optimization using the crystal sublattice model, the energy required for the transformation of pure elements Fe and Mn from the fcc phase to the hcp phase is:

9. The Fe-Mn-Si alloy composition design method according to claim 1, characterized in that, In step (4), the chemical driving force energy index is a thermodynamic energy parameter related to austenite stability calculated by the optimized DIMT chemical driving force model. This parameter is used to compare the stability of austenite under different alloying element combinations, thereby guiding the alloy composition design. Wherein, the thermodynamic energy parameter related to the stability of austenite is:

10. A Fe-Mn-Si alloy, characterized in that, The Fe-Mn-Si alloy is obtained by composition design based on the composition design method of DIMT chemical driving force according to any one of claims 1 to 9.

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