Annealing simulation method of body-centered cubic structure high-entropy alloy containing short-range ordered structure

Abstract

The invention relates to an annealing simulation method of a body-centered cubic structure high-entropy alloy containing a short-range ordered structure, which comprises the following steps of: constructing a high-entropy alloy model, performing energy calculation by adopting an EAM potential function, and performing annealing and atom exchange treatment by combining molecular dynamics and a Monte Carlo method. And finally, effective simulation of the short-range ordered structure of the high-entropy alloy is realized. According to the method, alloy components and microstructure evolution can be accurately controlled in the simulation process, compared with a traditional simulation method, the method has the obvious efficiency advantage, and powerful support is provided for research and application of the high-entropy alloy.

Description

Technical Field

[0001] The present invention relates to the field of annealing simulation methods, in particular to a method for designing an annealing simulation of a body-centered cubic high-entropy alloy containing a short-range ordered structure. Background Art

[0002] High-entropy alloys (HEAs) are a class of alloys composed of four or more metallic elements in equiatomic or near-equiatomic ratios. Due to their unique composition and structure, they have demonstrated excellent mechanical properties, radiation resistance, and thermal stability in research and practice. In recent years, HEAs have garnered widespread attention and application in fields such as aerospace, nuclear energy, and electronics.

[0003] The formation and evolution of short-range order (SRO) structures is a key research topic in the study of high-entropy alloys (HEAs). SRO refers to the tendency of certain elements to cluster together to form a locally ordered arrangement at the atomic scale. This structure significantly influences the mechanical properties and thermal stability of the alloy. For example, studies have found that in HEAs, certain elements (such as Ni-Cr) form SRO structures, which can even develop into nanoscale superlattice structures after long-term annealing.

[0004] Annealing is an important method for regulating the microstructure and properties of high-entropy alloys (HEAs). Annealing can eliminate residual stresses in the alloy, promote atomic diffusion and redistribution, and thus improve the alloy's microstructure and properties. For example, after annealing at 590°C, the CuCrFeMnTiAl HEA retains the as-cast hexagonal close-packed (HCP) and face-centered cubic (FCC) phases and also forms a body-centered cubic (BCC) solid solution. Furthermore, increasing the annealing temperature increases the size of dendrites, further affecting the alloy's microstructure.

[0005] Annealing simulation methods are crucial in the preparation and application of high-entropy alloys. By simulating the annealing process, we can predict the microstructural changes in the alloy under different annealing conditions, thereby optimizing the annealing process and improving the alloy's properties. For example, the LAMMPS software has been used to simulate the annealing process of high-entropy alloys. By controlling the heating rate and annealing temperature, the structural evolution of the alloy under different conditions can be studied.

[0006] The thermal stability of high-entropy alloys is also a research focus. Studies have shown that high-entropy alloys can maintain structural stability even after high-temperature annealing, attributing this to the thermodynamic stability brought about by their high mixing entropy. For example, molecular dynamics (MD) and Monte Carlo (MC) simulations have shown that certain high-entropy alloys maintain a relatively uniform distribution of their constituent elements after high-temperature annealing, demonstrating excellent thermal stability.

[0007] In summary, annealing simulation methods for high-entropy alloys are crucial for understanding and regulating their microstructure and properties. By simulating the annealing process, we can delve deeper into the formation and evolution of short-range ordered structures, providing theoretical support and technical guidance for the development of high-entropy alloy materials. Summary of the Invention

[0008] In response to the following technical problems in the current research on high-entropy alloys: (1) existing simulation methods are difficult to effectively simulate the formation and evolution of short-range ordered structures in high-entropy alloys; (2) traditional simulation methods are difficult to accurately adjust the atomic ratio and distribution when dealing with complex alloy components; (3) there is a lack of efficient simulation processes for molecular dynamics and Monte Carlo methods, resulting in low simulation efficiency; (4) it is difficult to accurately control the annealing temperature and relaxation process during the simulation process. The present invention constructs a high-entropy alloy model, uses EAM potential functions for energy calculation, and combines molecular dynamics and Monte Carlo methods for annealing and atom exchange treatment, ultimately achieving effective simulation of the short-range ordered structure of high-entropy alloys. This method can accurately control the alloy composition and microstructure evolution during the simulation process, has obvious efficiency advantages compared to traditional simulation methods, and provides strong support for the research and application of high-entropy alloys.

[0009] The present invention adopts the following technical solutions:

[0010] A method for simulating annealing of a body-centered cubic high-entropy alloy containing a short-range ordered structure comprises the following steps:

[0011] Step 1. Initial system setup: Set the boundary conditions and atomic species in the LAMMPS software, and define the lattice constant, loading temperature, annealing temperature, and time variables.

[0012] Build a high entropy alloy model: set the size of the simulation box and build a body-centered cubic lattice, define the simulation box area, create the simulation box and atoms, set the proportion of different types of atoms, select the potential function and set the time step;

[0013] Step 2: Energy minimization process: Calculate the potential energy of each atom, the total potential energy, and the system temperature, set the thermodynamic output parameters, use the energy minimization method to minimize the energy of the system, and reset the time step;

[0014] Step 3, Monte Carlo atom exchange process: Output atomic configuration information, define exchange parameters, simulate under constant pressure and constant temperature ensemble, and output energy information. Use the Monte Carlo method to randomly exchange each atom in the high entropy alloy model.

[0015] Step 4: Annealing process: annealing treatment is performed under a constant pressure and constant temperature ensemble;

[0016] Step 5, cooling and relaxation process: Output atomic configuration information and energy information, perform cooling and relaxation processing under constant pressure and constant temperature ensemble, reset the time step, and save the simulation results.

[0017] Furthermore, in step 1, the EAM potential function is selected and the time step is set to 0.001 ns.

[0018] Furthermore, the atomic exchange performed using the Monte Carlo method in step 3 lasts for 50 ns.

[0019] Furthermore, in step 5, the cooling process is maintained for 30 ns, and the relaxation process is maintained for 20 ns.

[0020] After adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0021] The present invention adopts a simulated annealing method to successfully obtain a body-centered cubic high-entropy alloy structure with short-range ordered distribution.

[0022] The present invention combines molecular dynamics with the Monte Carlo exchange method and performs calculations based on the LAMMPS framework, which has obvious computational efficiency advantages over traditional simulation calculations.

[0023] The present invention can output the cfg data file and radial distribution function rdf.dat of the short-range ordered structure generation and evolution in body-centered cubic high-entropy alloys. The properties of this short-range ordered structure can be further analyzed through post-processing software such as Ovito, facilitating subsequent research and analysis.

[0024] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the process of the present invention;

[0026] Figure 2 This is a schematic diagram of the high entropy alloy model after energy minimization;

[0027] Figure 3 Schematic diagram of the high entropy alloy model after Monte Carlo exchange (20ns);

[0028] Figure 4 Schematic diagram of the high entropy alloy model after Monte Carlo exchange (30ns);

[0029] Figure 5 Schematic diagram of the high entropy alloy model after annealing simulation. DETAILED DESCRIPTION

[0030] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0031] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0032] Example 1

[0033] Taking HfNbTaZr body-centered cubic high entropy alloy as an example,

[0034] Step 1: Initial system setup: Set the simulation unit system to metal, the boundary condition to ppp, and the atomic species to atomic. Define the lattice constants of the HfNbTaZr body-centered cubic high entropy alloy The loading temperature is 1K, the annealing temperature is 300K, and the time is variable.

[0035] Build the model: Set the simulation box dimensions to 20 x 14 x 14 and construct a body-centered cubic (BCC) lattice. Define the simulation box region, create the simulation box and atoms, and set the ratio of the four metal principal elements to 1:1:1:1.

[0036] Potential function and time step settings: Select the EAM potential function and load the potential function parameter file. Set the time step to 0.001ns, set the neighbor list update frequency, and delete overlapping atoms.

[0037] Step 2: Energy minimization process: Calculate the potential energy of each atom, the total potential energy, and the system temperature. Set the thermodynamic output parameters. Use the energy minimization method to minimize the energy of the system and reset the time step, such as Figure 2 shown.

[0038] Output file settings: Output atomic configuration information and assign initial velocities to atoms. Calculate the radial distribution function and output the radial distribution function data (rdf.dat). Calculate the energy of the system and output the energy information.

[0039] Step 3: Monte Carlo atom exchange process: Output atomic configuration information and define exchange parameters. Simulate under constant pressure and temperature (NPT) ensemble and output energy information. Use Monte Carlo method to perform atom exchange and run for 50ns. Figure 3 and Figure 4 shown.

[0040] Step 4: Simulated annealing: annealing is performed under a constant pressure and constant temperature (NPT) ensemble.

[0041] Step 5: Cooling and relaxation process: Output atomic configuration information and energy information. Cooling process is performed under constant pressure and temperature (NPT) ensemble, and relaxation is performed for 30ns. Relaxation process is performed under constant pressure and temperature (NPT) ensemble, and run for 20ns. Reset the time step and save the simulation results, such as Figure 5 shown.

[0042] The foregoing is an example of the best mode of carrying out the present invention. Any portion not described in detail herein is common knowledge within the skill of one of ordinary skill in the art. The scope of protection of the present invention is determined by the claims. Any equivalent transformation based on the technical teachings of the present invention is also within the scope of protection of the present invention.

Claims

1. A method for simulating the annealing of a body-centered cubic high entropy alloy with a short-range ordered structure, characterized in that: The following steps are involved: Step 1. Initial system setup: Set the boundary conditions and atomic species in the LAMMPS software, and define the lattice constant, loading temperature, annealing temperature, and time variables. Build a high entropy alloy model: set the size of the simulation box and build a body-centered cubic lattice, define the simulation box area, create the simulation box and atoms, set the proportion of different types of atoms, select the potential function and set the time step; Step 2: Energy minimization process: Calculate the potential energy of each atom, the total potential energy, and the system temperature, set the thermodynamic output parameters, use the energy minimization method to minimize the energy of the system, and reset the time step; Step 3, Monte Carlo atom exchange process: Output atomic configuration information, define exchange parameters, simulate under constant pressure and constant temperature ensemble, and output energy information. Use the Monte Carlo method to randomly exchange each atom in the high entropy alloy model. Step 4: Annealing process: annealing treatment is performed under a constant pressure and constant temperature ensemble; Step 5, cooling and relaxation process: Output atomic configuration information and energy information, perform cooling and relaxation processing under constant pressure and constant temperature ensemble, reset the time step, and save the simulation results.

2. The annealing simulation method of a body-centered cubic high entropy alloy with a short-range ordered structure according to claim 1, characterized in that: In step 1, the EAM potential function is selected and the time step is set to 0.001 ns.

3. The annealing simulation method of a body-centered cubic high entropy alloy with a short-range ordered structure according to claim 1, characterized in that: The atomic exchange using the Monte Carlo method in step 3 lasts for 50 ns.

4. The annealing simulation method of a body-centered cubic high entropy alloy with a short-range ordered structure according to claim 1, characterized in that: In step 5, the cooling process is maintained for 30 ns, and the relaxation process is maintained for 20 ns.

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