Modeling method of multi-principal-element alloy short-range ordered structure

Abstract

The invention provides a modeling method of a multi-principal-element alloy short-range ordered structure. The method comprises the following steps: firstly, constructing an orthogonal simulation box, determining a spatial region omega according to the shape characteristics and spatial position of a pre-constructed short-range ordered structure, marking atoms in the omega region in a single crystal atom configuration, and then, according to the constructed short-range ordered structure BxCy, marking atoms in the omega region in the simulation box outside the omega region according to the proportion of target alloy elements. The method comprises the following steps of: adding a replacement element A into a region outside an omega region, then setting a simulation box as a periodic boundary condition, and finally forming ordered distribution after full evolution under isothermal and isobaric conditions by combining a Monte Carlo method and dynamic relaxation in molecular dynamics. And the interaction research of the internal microstructure of the related alloy can be accelerated, so that the macroscopic performance of the material is accurately adjusted according to a specific interaction mechanism, and a theoretical basis is provided for material research and development and material scientific experiment research.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of computational materials science, and particularly relates to a modeling method of short-range ordered structure of multi-principal element alloy. BACKGROUND

[0002] As a new type of advanced structural material, multi-principal element alloy breaks the traditional alloy design concept dominated by single element, and exhibits excellent comprehensive performance through the synergistic effect of multiple principal elements. Ti-Zr-based Ti 42.5 Zr 42.5 Multi-principal element alloys represented by Nb5Ta5V5 system not only have high specific strength and excellent high-temperature resistance, but also have good hydrogen storage performance, which can realize the integration of structure and function. Therefore, it has broad application prospects in aerospace, energy storage, high-end equipment manufacturing and other key fields, and has become one of the research hotspots in the field of materials science. With the continuous improvement of industrial requirements for material performance, the performance optimization and regulation of multi-principal element alloy has become the core direction to promote its industrial application.

[0003] In the preparation and service process of multi-principal element alloy, the microstructure plays a decisive role in its macroscopic performance. Due to the complex interatomic interaction between multiple elements in the alloy, including affinity and repulsion, each element in the smelting and subsequent processing process will not be randomly distributed, but will easily occur in the form of specific element segregation, and then form short-range ordered structure. Studies have shown that this kind of short-range ordered structure is usually regarded as the precursor of intermetallic compounds, and plays an important role in the key mechanical properties of multi-principal element alloy such as plastic deformation, strength regulation and fatigue life. At present, by regulating the morphology (such as chain, cluster), size and spatial distribution of short-range ordered structure, etc., it has become the main technical path to realize the strengthening and toughening of multi-principal element alloy. Therefore, it is of great significance to the design and optimization of multi-principal element alloy to deeply study the formation mechanism of short-range ordered structure and its correlation with material performance.

[0004] With the cross-fusion of material science and computer science, multiscale simulation technology has become an important means to study the relationship between microstructure and performance of materials. At the micro-nano scale, molecular dynamics method is widely used in the simulation of the interaction between crystal defects (such as dislocations, vacancies, etc.) in metal materials due to its ability to accurately describe the motion and interaction of atoms, which provides strong support for revealing the micro-mechanism of material mechanical behavior. However, in the field of modeling short-range ordered structure in multi-principal element alloy, the existing technology still faces significant challenges: when long-time evolution simulation is performed by molecular dynamics method, the short-range ordered structure formed often has randomness, and it is difficult to stably construct short-range ordered structure with specific morphology (such as pre-set chain-like, cluster-like). This technical bottleneck prevents researchers from systematically studying the interaction rules between specific morphology short-range ordered structure and crystal defects, which further restricts the in-depth understanding of the performance regulation mechanism of multi-principal element alloy, and it is also difficult to provide precise theoretical guidance for experimental research of multi-principal element alloy through simulation means.

[0005] In summary, there is an urgent need for a universal modeling method that can accurately construct specific morphology short-range ordered structure in multi-principal element alloy to solve the problem of uncontrollable morphology of short-range ordered structure in existing molecular dynamics simulation, and to provide a reliable model basis for subsequent research on the interaction between short-range ordered structure and crystal defects and optimization of the performance of multi-principal element alloy. SUMMARY

[0006] The present application aims to at least solve one of the above technical problems existing in the prior art. To this end, the present application provides a modeling method for short-range ordered structure in multi-principal element alloy, which can accelerate the research on the interaction of internal microstructure of related alloy, so as to accurately adjust the macroscopic performance of the material according to the specific interaction mechanism, and provide a theoretical basis for material research and experimental research in material science.

[0007] Short-range ordered structure exists universally in multi-principal element alloy, and the short-range ordered structure observed in current experiments has various morphological characteristics (such as chain-like, cluster-like, etc.). In the field of computational materials science, it is very difficult to construct short-range ordered structure with specific morphology, which is due to the fact that the short-range ordered structure obtained by long-time atomic-scale simulation evolution usually has different morphologies, and it is difficult to study the interaction between short-range ordered structure with specific morphology and each crystal defect. In view of this situation, the present application combines Monte Carlo and molecular dynamics method, selects a specific shape of space region Ω, and only performs atomic replacement and dynamic relaxation in this region, so that BxCy type short-range ordered structure is spontaneously formed in the space region Ω, thus obtaining short-range ordered structure with specific morphology, which provides a model basis for the subsequent research on the interaction between multi-defects and short-range ordered structure with specific morphology.

[0008] This invention provides a modeling method for short-range ordered structures of multi-principal element alloys, which constructs short-range ordered structures of specific shapes in an orthogonal simulation box, and includes the following steps:

[0009] (1) Construct an orthogonal simulation box, fill it with a multi-principal element alloy single crystal atomic model, and contain only one matrix element A;

[0010] (2) Determine a spatial region Ω based on the shape characteristics and spatial position of the pre-constructed short-range ordered structure, mark the atoms in the Ω region in the single-crystal atomic configuration, and count the number of atoms in the region.

[0011] (3) Based on the constructed short-range ordered structure B x C y M z Elements B, C, and M replace all elements A in the Ω region according to the atomic ratio x:y:z, ensuring that the Ω region consists entirely of elements B, C, and M.

[0012] (4) Inside the simulation box outside the Ω region, replace element A with the target alloy element ratio and add it to the region outside the Ω region to ensure that the overall element ratio meets the expected element ratio of the multi-principal alloy to be constructed.

[0013] (5) Set the simulation box to periodic boundary conditions, and use molecular dynamics software and interatomic interaction potential to statically relax the simulation box and release internal stress.

[0014] (6) Combining the Monte Carlo method and the kinetic relaxation in molecular dynamics, under isothermal and isobaric conditions, only B, C and M atoms in the Ω region are allowed to exchange positions according to the minimum energy criterion, and after sufficient evolution, they form an ordered distribution.

[0015] The modeling method of this invention, through precise design of the modeling process and control of atomic evolution rules, has at least the following beneficial effects:

[0016] This method overcomes a core technological bottleneck, achieving precise and controllable short-range ordered structures. Existing molecular dynamics simulations for constructing short-range ordered structures in multi-principal alloys often result in random and uncontrollable structural morphologies due to long-term evolution, making it difficult to meet the research needs of short-range ordered structures with specific morphologies (such as chain-like or cluster-like structures). However, this method, by defining a specific spatial region Ω+ and limiting the design of the evolution of B and C atoms within the Ω region, can directionally construct short-range ordered structures of predetermined shapes and sizes. This completely breaks through the technical bottleneck of uncontrollable morphology in traditional modeling, providing a standardized model for studying the interaction between short-range ordered structures with specific morphologies and crystal defects (such as dislocations and vacancies), filling a technological gap in precise modeling in this field.

[0017] This ensures the reliability of the model and provides a high-quality foundation for the study of microscopic mechanisms. On the one hand, step (4) ensures that the overall element ratio of the multi-principal alloy strictly conforms to the expected ratio (e.g., Ti:Zr:Nb:Ta:V = 42.5:42.5:5:5:5 in Ti-Zr-based alloys) by first counting the number of B and C atoms that have been replaced in the Ω region and then calculating the replacement amount of each element outside the Ω region, thus avoiding the impact of the element ratio deviation on the subsequent performance correlation analysis. On the other hand, step (5) applies periodic boundary conditions and uses the conjugate gradient method / steepest descent method for static relaxation, which can effectively eliminate interference factors such as the free surface and internal stress of the simulation box, making the stress level of the model approach zero, and restoring the real microscopic environment of the multi-principal alloy to the greatest extent, thus ensuring the accuracy and reliability of the subsequent atomic evolution simulation results and providing a high-quality model foundation for revealing the formation mechanism and action law of short-range ordered structures.

[0018] This method improves research efficiency and accelerates the performance optimization and development of multi-principal element alloys. Traditional methods require repeated and lengthy molecular dynamics simulations to obtain short-range ordered structures of target morphologies, which is time-consuming and inefficient. This new method, through directional region evolution design, only requires energy-lower-criterion substitution of B and C atoms within the Ω region to rapidly form ordered structures, significantly shortening the modeling cycle. Furthermore, this method is universally applicable—it can be adapted to multi-principal element alloys with different crystal structures such as body-centered cubic, face-centered cubic, and hexagonal close-packed alloys, and supports the construction of various types of short-range ordered structures, such as TaV2 or Zr5Al3, without the need to repeatedly develop modeling schemes for different alloy systems. Based on this, researchers can quickly conduct correlation studies on specific short-range ordered structures, crystal defects, and macroscopic properties, accurately locate key targets for performance regulation, provide theoretical guidance for optimizing the toughness, high-temperature resistance, and other properties of multi-principal element alloys, and thus accelerate the process of multi-principal element alloys from laboratory research to industrial application.

[0019] Furthermore, the modeling method of this invention combines the Monte Carlo method (based on the minimum energy criterion of atomic exchange) with molecular dynamics (kinetic relaxation) and limits the range of local evolution, forming a new paradigm for modeling the microstructures of multi-principal alloys through directed construction and efficient evolution. This paradigm can not only be applied to short-range ordered structure modeling, but also provide ideas for the directed construction of specific microstructures in other materials (such as high-entropy ceramics and intermetallic compounds), expanding the technical path for precise control of microstructures in computational materials science and possessing strong methodological value.

[0020] Therefore, the modeling method for constructing short-range ordered structures in multi-principal alloys proposed in this invention can accelerate the study of the interaction of microstructures within related alloys, thereby enabling precise adjustments to the macroscopic properties of materials based on specific interaction mechanisms, and providing a theoretical foundation for material development and experimental research in materials science.

[0021] According to some embodiments of the present invention, in step (1), the crystal structure of the constructed orthogonal simulation box is body-centered cubic, face-centered cubic, or hexagonal close-packed.

[0022] According to some embodiments of the present invention, in step (1), the matrix element A is Ti, and the multi-principal element alloy is A. a B b C c D d E e .

[0023] According to some embodiments of the present invention, in step (1), the matrix element A is Ti, and the multi-principal element alloy is Ti-Zr based Ti. 42.5 Zr 42.5 Nb5Ta5V5 system.

[0024] According to some embodiments of the present invention, in step (2), the shape of the determined spatial region Ω is chain-like or cluster-like.

[0025] According to some embodiments of the present invention, in step (2), when the spatial region Ω is clustered, its specific shape is spherical, the center of the sphere is set to the exact center of the simulated box, and the radius of the sphere is set to...

[0026] According to some embodiments of the present invention, in step (3), the short-range ordered structure constructed is B. x C y M z .

[0027] According to some embodiments of the present invention, in step (3), the constructed short-range ordered structure B x C y It is either TaV2 or Zr5Al3.

[0028] According to some embodiments of the present invention, in step (3), when the short-range ordered structure is TaV2, element B is Ta, element C is V, and the atomic ratio x:y is 1:2; when the short-range ordered structure is Zr5Al3, element B is Zr, element C is Al, and the atomic ratio x:y is 5:3.

[0029] According to some embodiments of the present invention, in step (3), after element B and element C replace element A, there is no matrix element A remaining in the spatial region Ω. For example, after replacing Ti atoms with Ta and V in the spherical region Ω, it should be ensured that there are no Ti atoms in the region Ω.

[0030] According to some embodiments of the present invention, in step (4), when performing atomic substitution within the simulated box outside the spatial region Ω, it is necessary to first count the number of atoms of element B and element C that have been substituted within the spatial region Ω, and then calculate the number of atoms of each alloy element to be substituted outside the Ω region, so as to ensure that the overall element ratio meets expectations. That is, in order to ensure that the ratio of each alloy element meets expectations, atomic substitution should be performed within the simulated box outside the spatial region Ω. In addition, the number of atoms substituted should take into account the B and C atoms that have been substituted within the spherical region Ω.

[0031] According to some embodiments of the present invention, in step (5), the static relaxation method adopts the conjugate gradient method or the steepest descent method.

[0032] According to some embodiments of the present invention, in step (6), atomic exchange and dynamic relaxation only occur within the spatial region Ω, and the time step of the atomic evolution process is set to 1fs, with atomic exchange performed every 50 time steps.

[0033] According to some embodiments of the present invention, in step (6), after a long period of evolution, elements B and C in the Ω region form a short-range ordered structure B. x C y Consistent atomic distribution characteristics; alloying elements outside the Ω region exhibit a random distribution.

[0034] According to some embodiments of the present invention, a method for modeling short-range ordered structures of multi-principal element alloys may include the following steps:

[0035] (1) Ti-Zr based Ti 42.5 Zr 42.5 Taking the Nb5Ta5V5 multi-principal alloy as an example, the single-crystal atomic configuration of the TiZrNbTaV multi-principal alloy is constructed. The simulation box is an orthogonal box and contains only one matrix element, Ti.

[0036] (2) Determine a spatial region Ω based on the shape characteristics and spatial location of the pre-constructed short-range ordered structure, such as selecting a spherical region (cluster-like), and setting the center of this region as the exact center of the simulation box, with the spherical radius set to... The atoms in the spherical region Ω are labeled, and the number of atoms n in the region is counted.

[0037] (3) Based on the constructed short-range ordered structure BxCy, taking the TaV2 short-range ordered structure as an example, elements Ta and V replace all elements Ti in the Ω region in an atomic ratio of 1:2 to ensure that the Ω region is filled with elements Ta and V.

[0038] (4) Inside the simulated box outside the spherical Ω region, by replacing element Ti, other alloying elements Ta, V, Zr, and Nb are added to the region outside the Ω region in the expected proportion to ensure that the overall element proportion meets the expected element ratio of the multi-principal alloy (e.g., Ti:Zr:Nb:Ta:V = 42.5:42.5:5:5:5).

[0039] (5) Set the simulation box to periodic boundary conditions to prevent free surfaces and other crystal defects from affecting the relaxation process. Use molecular dynamics software and interatomic interaction potentials to perform static relaxation on the simulation box, release the internal stress in all directions, and ensure that the stress level in all directions of the simulation box approaches zero;

[0040] (6) Combining the Monte Carlo method and kinetic relaxation in molecular dynamics, atoms in the simulated box are subjected to long-term evolution in an isothermal and isobaric ensemble. Based on the minimum energy criterion, atomic positions are interchanged only between elements Ta and V within the Ω region. After long-term evolution, elements Ta and V within the Ω region exhibit an ordered distribution, forming an atomic distribution characteristic close to TaV2. Elements Ti, Zr, Nb, Ta, and V outside the Ω region are randomly distributed, thus obtaining a spherical short-range ordered structure. Attached Figure Description

[0041] Figure 1 This is the atomic configuration diagram of a body-centered cubic pure titanium single crystal.

[0042] Figure 2 This is the atomic configuration diagram of the spatial region Ω (white dashed line region) after replacing Ti atoms with Ta and V atoms.

[0043] Figure 3 It is the atomic configuration diagram outside the spatial region Ω, after replacing Ti atoms with Zr, Nb, Ta, and V atoms.

[0044] Figure 4 It is an atomic comparison diagram of Ta and V atoms before and after the exchange within the spatial region Ω, using Monte Carlo / molecular dynamics. Detailed Implementation

[0045] In its specific implementation, the modeling method for short-range ordered structures of multi-principal element alloys of the present invention includes the following steps: constructing an initial single-crystal atomic configuration of the multi-principal element alloy; defining a spatial region Ω of a specific shape / position within the simulation box, and replacing all A atoms within it with the desired short-range ordered structure (such as B atoms) according to the quantity ratio x:y. x C yElements B and C are selected from the matrix A. Outside the Ω region, other alloying elements (B, C, D, and E, etc.) are randomly replaced with other alloying elements according to the target alloying element ratio. Periodic boundary conditions are applied to induce molecular dynamics static relaxation and release internal stress. Under isothermal and isobaric conditions, combining Monte Carlo and molecular dynamics methods, only B and C atoms within the Ω region are allowed to interchange positions according to the lowest energy criterion, allowing for full evolution. Ultimately, B and C exhibit an ordered distribution within the Ω region, while elements in other regions remain randomly distributed, forming a short-range ordered structure of the target shape.

[0046] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0047] Example

[0048] Modeling short-range ordered structures in multi-principal element alloys involves the following steps:

[0049] (1) Ti-Zr based Ti 42.5 Zr 42.5 Taking Nb5Ta5V5 multi-principal alloy as an example, the single-crystal atomic configuration of TiZrNbTaV multi-principal alloy is constructed, such as... Figure 1 As shown. The constructed simulation box is an orthogonal box and contains only one matrix element Ti. The orientations of the three axes of the simulation box are as follows:

[112] ,

[0050] (2) Determine a spatial region Ω based on the shape characteristics and spatial location of the pre-constructed short-range ordered structure. This region can be cluster-shaped or chain-shaped, etc. (see...) Figure 2 (within the white dashed line area), mark all Ti atoms in the Ω region and count the total number of Ti atoms n in the region.

[0051] (3) Based on the short-range ordered structure of the TaV2 type in the TiZrNbTaV multi-principal element alloy, all Ti elements in the Ω region are replaced by Ta and V in an atomic ratio of 1:2, such as... Figure 2 As shown. Figure 2 In the diagram, (a) represents a cluster-shaped region, and (b) represents a chain-shaped region. After this step, the simulation box contains only three alloying elements: Ti, Ta, and V, with Ta and V atoms distributed within the Ω region.

[0052] (4) Inside the simulation box outside the Ω region (white dashed line region), other alloying elements Ta, V, Zr, and Nb are replaced by element Ti to complete the construction that conforms to Ti. 42.5 Zr 42.5 Atomic model of Nb5Ta5V5 multi-principal element alloying, such as Figure 3 As shown, Figure 3 In the diagram, (a) represents a cluster-shaped region, and (b) represents a chain-shaped region. At this point, Ta and V atoms are distributed both within and outside the Ω region.

[0053] (5) The simulation box is set as a periodic boundary condition to prevent free surfaces and other crystal defects from affecting the relaxation process. Static relaxation of the simulation box is performed using molecular dynamics software and interatomic interaction potentials to release internal stresses in all directions and ensure the stability of Ti. 42.5 Zr 42.5 The stress level of the Nb5Ta5V5 multi-principal-element alloy system approaches zero in all directions;

[0054] (6) Combining the Monte Carlo method and kinetic relaxation in molecular dynamics, atoms in the simulated box were subjected to long-term evolution in an isothermal and isobaric ensemble, with a time step set to 1 fs and an atomic exchange occurring every 50 time steps. Based on the minimum energy criterion, atomic positions were only exchanged between elements Ta and V within the Ω region. After long-term evolution, elements Ta and V within the Ω region eventually exhibited an ordered distribution, forming an atomic distribution characteristic close to TaV2, such as... Figure 4 As shown, Figure 4 In the diagram, (a) represents a clustered region, and (b) represents a chain-like region. Figure 4 It was shown that after atomic exchange, the Ta and V atoms in the Ω region gradually changed from a random distribution to a TaV2 type atomic distribution, that is, cluster-like / chain-like TaV2 type short-range ordered structures were obtained respectively.

[0055] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A modeling method for short-range ordered structures of multi-principal element alloys, wherein the general chemical formula of the multi-principal element alloy is A. a B x C y M z M is absent or is at least one metallic element, characterized in that, Construct short-range ordered structures of a specific shape within an orthogonal simulation box, including the following steps: (1) Construct an orthogonal simulation box, fill it with a multi-principal element alloy single crystal atomic model, and contain only one matrix element A; (2) Determine a spatial region Ω based on the shape characteristics and spatial position of the pre-constructed short-range ordered structure, mark the atoms in the Ω region in the single-crystal atomic configuration, and count the number of atoms in the region. (3) Based on the constructed short-range ordered structure B x C y M z Elements B, C, and M replace all elements A in the Ω region according to the atomic ratio x:y:z, ensuring that the Ω region consists entirely of elements B, C, and M. (4) Inside the simulation box outside the Ω region, replace element A with the target alloy element ratio and add it to the region outside the Ω region to ensure that the overall element ratio meets the expected element ratio of the multi-principal alloy to be constructed. (5) Set the simulation box to periodic boundary conditions, and use molecular dynamics software and interatomic interaction potential to statically relax the simulation box and release internal stress. (6) Combining the Monte Carlo method and the kinetic relaxation in molecular dynamics, under isothermal and isobaric conditions, only B, C and M atoms in the Ω region are allowed to exchange positions according to the minimum energy criterion, and after sufficient evolution, they form an ordered distribution.

2. The modeling method according to claim 1, characterized in that, In step (1), the crystal structure of the constructed orthogonal simulation box is body-centered cubic, face-centered cubic, or hexagonal close-packed.

3. The modeling method according to claim 1, characterized in that, In step (1), the matrix element A is Ti, and the multi-principal element alloy is A. a B b C c D d E e ; and / or, the multi-principal element alloy is Ti-Zr based Ti 42.5 Zr 42.5 Nb5Ta5V5 system.

4. The modeling method according to claim 1, characterized in that, In step (2), the shape of the determined spatial region Ω is either chain-like or cluster-like; and / or, when the spatial region Ω is cluster-like, its specific shape is spherical, with the center of the sphere set to the exact center of the simulated box, and the radius of the sphere set to...

5. The modeling method according to claim 1, characterized in that, In step (3), the short-range ordered structure constructed is B. x C y M z ; and / or, constructing a short-range ordered structure B x C y It is either TaV2 or Zr5Al3; and / or, when the short-range ordered structure is TaV2, element B is Ta, element C is V, and the atomic ratio x:y is 1:2; when the short-range ordered structure is Zr5Al3, element B is Zr, element C is Al, and the atomic ratio x:y is 5:

3.

6. The modeling method according to claim 1, characterized in that, In step (3), after element B and element C replace element A, there is no matrix element A remaining in the spatial region Ω.

7. The modeling method according to claim 1, characterized in that, In step (4), when performing atomic substitution in the simulation box outside the spatial region Ω, it is necessary to first count the number of atoms of element B and element C that have been substituted in the spatial region Ω, and then calculate the number of atoms of each alloy element that need to be substituted outside the Ω region, so as to ensure that the overall element ratio meets expectations.

8. The modeling method according to claim 1, characterized in that, In step (5), the static relaxation method adopts either the conjugate gradient method or the steepest descent method.

9. The modeling method according to claim 1, characterized in that, In step (6), atomic exchange and dynamic relaxation only occur within the spatial region Ω, and the time step of the atomic evolution process is set to 1fs, with an atomic exchange performed every 50 time steps.

10. The modeling method according to claim 1, characterized in that, In step (6), after a long period of evolution, elements B and C in the Ω region form a short-range ordered structure B. x C y Consistent atomic distribution characteristics; alloying elements outside the Ω region exhibit a random distribution.

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