A molecular dynamics simulation method for grinding of FeNiCrCoAl high entropy alloy

Abstract

A molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloys relates to a molecular dynamics simulation calculation method for grinding of high entropy alloys. The present invention is to solve the problem that molecular dynamics simulation cannot realize the simulation of high entropy alloy grinding. The present invention can realize the dynamic simulation of the entire friction process of high entropy alloys. The molecular dynamics simulation can reveal the influence of the distribution of different elements in the alloy on the friction coefficient and surface wear, predict the material deformation, interface shear and surface morphology evolution during the friction process, optimize the surface treatment method and interface design of high entropy alloys, and improve its friction characteristics and wear resistance in specific engineering applications. This optimized design can effectively extend the service life of the material, improve its work efficiency, and explore the application potential of new high entropy alloys in different engineering fields.

Description

Technical Field

[0001] The invention relates to a molecular dynamics simulation calculation method for high entropy alloy grinding. Background Art

[0002] High Entropy Alloys (HEAs) are a new type of material composed of multiple elements with uniform distribution and complex microstructure. They are usually composed of five or more elements. Unlike traditional alloys, their chemical composition is more uniform. This uniformity gives high entropy alloys excellent mechanical properties, corrosion resistance and high temperature stability. The excellent performance of high entropy alloys often stems from the complexity and uniformity of their microstructure. Traditional experimental methods make it difficult to directly observe and understand the atomic-scale behavior of high entropy alloys during grinding. Therefore, molecular dynamics simulation has become an important means to study the grinding behavior of high entropy alloys, which can simulate and analyze the atomic interactions, surface morphology changes and local strain distribution during friction at the atomic level.

[0003] Molecular dynamics simulation can reveal the influence of the distribution of different elements in the alloy on the friction coefficient and surface wear, predict the material deformation, interface shear and surface morphology evolution during the friction process, optimize the surface treatment method and interface design of high entropy alloys, and improve their friction characteristics and wear resistance in specific engineering applications. This optimized design can effectively extend the service life of the material, improve its work efficiency, and explore the application potential of new high entropy alloys in different engineering fields. However, how to achieve high entropy alloy grinding in the existing technology is a difficult point in molecular dynamics simulation to study the friction deformation behavior of high entropy alloys. Summary of the invention

[0004] In order to solve the problem that molecular dynamics simulation cannot realize high entropy alloy grinding simulation, the present invention provides a molecular dynamics simulation calculation method for FeNiCrCoAl high entropy alloy grinding.

[0005] The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy of the present invention is carried out according to the following steps:

[0006] (1) Basic parameter setting: Use lammps to build a model and set up the simulation environment;

[0007] The simulation environment includes the unit, spatial dimension, boundary conditions, atom type, simulation time step and atomic neighbor parameters of the simulation system;

[0008] (2) Model establishment: The Fe atomic unit cell with fcc structure is used to establish the high entropy alloy precursor crystal model; there are five types of atoms in the high entropy alloy precursor crystal model, namely Fe, Ni, Cr, Co, and Al; iron atoms are first filled in the model area, and then the atomic replacement command settype / ratio is used to randomly replace the iron atoms with Ni, Cr, Co, and Al atoms according to the atomic percentage to obtain the Fe, Ni, Cr, Co, and Al high entropy alloy models, and the relative atomic mass of each atom is set;

[0009] (3) Minimize and relax the precursor crystal model:

[0010] (4) Add a vacuum layer in the z direction;

[0011] (5) Diamond tool modeling: Use the region sphere command to set the diamond tool region as a spherical region, that is, the diamond tool is a sphere, set the coordinates of the sphere center and the sphere radius, then fill C atoms in the spherical region and write the atomic mass of C;

[0012] (6) The high entropy alloy precursor crystal model is divided into two parts, namely the boundary part with a fixed bottom and the piece part where atoms can move;

[0013] (7) Calculate the piece layer temperature;

[0014] (8) Fix the atoms in the boundary part. The atoms in the boundary part are always subjected to 0 force and 0 speed during the entire grinding process.

[0015] (9) Potential function adopts alloy system tersoff / eam / alloy / lj / cut mixed potential;

[0016] (10) Pressing down the diamond tool and defining the pressing parameters of the diamond tool;

[0017] (11) Calculate the friction force of the piece layer: sum the friction forces of all atoms in the x, y, and z directions respectively, with the displacement step number being 1000, and save the friction force to a file;

[0018] (12) Use variable xcm(ball,x) to calculate the coordinates of the center of gravity of the ball, and use fix move transrot to rub the diamond tool in a straight line in the y direction while the diamond tool itself rotates;

[0019] (13) Run the grinding process and save the file. The resulting file is displayed in Ovito and a stress contour map is drawn.

[0020] The principles and beneficial effects of the present invention are:

[0021] The present invention can realize the dynamic simulation of the whole process of high entropy alloy friction. The molecular dynamics simulation can reveal the influence of the distribution of different elements in the alloy on the friction coefficient and surface wear, predict the material deformation, interface shear and surface morphology evolution during the friction process, optimize the surface treatment method and interface design of high entropy alloy, and improve its friction characteristics and wear resistance in specific engineering applications. This optimized design can effectively extend the service life of the material, improve its work efficiency, and explore the application potential of new high entropy alloys in different engineering fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The precursor crystal phase model of the amorphous model established in Example 1 has a fcc structure;

[0023] Figure 2 A model of the bottom boundary layer and the upper atomic layer with fixed model grouping in Example 1;

[0024] Figure 3 This is a model diagram of the grinding process of Example 1;

[0025] Figure 4 This is the stress distribution cloud diagram of the grinding process in Example 1. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any reasonable combination of the specific implementation modes.

[0027] Specific implementation method 1: The molecular dynamics simulation calculation method for grinding FeNiCrCoAl high entropy alloy in this implementation method is carried out according to the following steps:

[0028] (1) Basic parameter setting: Use lammps to build a model and set up the simulation environment;

[0029] The simulation environment includes the unit, spatial dimension, boundary conditions, atom type, simulation time step and atomic neighbor parameters of the simulation system;

[0030] (2) Model establishment: The Fe atomic unit cell with fcc structure is used to establish the high entropy alloy precursor crystal model; there are five types of atoms in the high entropy alloy precursor crystal model, namely Fe, Ni, Cr, Co, and Al; iron atoms are first filled in the model area, and then the atomic replacement command settype / ratio is used to randomly replace the iron atoms with Ni, Cr, Co, and Al atoms according to the atomic percentage to obtain the Fe, Ni, Cr, Co, and Al high entropy alloy models, and the relative atomic mass of each atom is set;

[0031] (3) Minimize and relax the precursor crystal model:

[0032] (4) Add a vacuum layer in the z direction;

[0033] (5) Diamond tool modeling: Use the region sphere command to set the diamond tool region as a spherical region, that is, the diamond tool is a sphere, set the coordinates of the sphere center and the sphere radius, then fill C atoms in the spherical region and write the atomic mass of C;

[0034] (6) The high entropy alloy precursor crystal model is divided into two parts, namely the boundary part with a fixed bottom and the piece part where atoms can move;

[0035] (7) Calculate the piece layer temperature;

[0036] (8) Fix the atoms in the boundary part. The atoms in the boundary part are always subjected to 0 force and 0 speed during the entire grinding process.

[0037] (9) Potential function adopts alloy system tersoff / eam / alloy / lj / cut mixed potential;

[0038] (10) Pressing down the diamond tool and defining the pressing parameters of the diamond tool;

[0039] (11) Calculate the friction force of the piece layer: sum the friction forces of all atoms in the x, y, and z directions respectively, with the displacement step number being 1000, and save the friction force to a file;

[0040] (12) Use variable xcm(ball,x) to calculate the coordinates of the center of gravity of the ball, and use fix move transrot to rub the diamond tool in a straight line in the y direction while the diamond tool itself rotates;

[0041] (13) Run the grinding process and save the file. The resulting file is displayed in Ovito and a stress contour map is drawn.

[0042] This implementation method can realize the dynamic simulation of the entire friction process of high entropy alloys. Molecular dynamics simulation can reveal the influence of the distribution of different elements in the alloy on the friction coefficient and surface wear, predict the evolution of material deformation, interface shear and surface morphology during the friction process, and optimize the surface treatment method and interface design of high entropy alloys to improve their friction characteristics and wear resistance in specific engineering applications. This optimized design can effectively extend the service life of the material, improve its work efficiency, and explore the application potential of new high entropy alloys in different engineering fields.

[0043] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that: the unit of the simulation system in step (1) is metal; the spatial dimension is 3; the boundary condition is ppp; that is, the boundaries are periodic in the x, y, and z directions; the atom type is atomic; the simulation time step is 0.001; and the atomic neighbor parameter is 2bin.

[0044] Specific implementation method three: The difference between this implementation method and specific implementation method one or two is that the atomic percentages of Fe, Ni, Cr, Co and Al in the precursor crystal model in step (2) are 1:1:1:1:1 respectively.

[0045] Specific implementation method 4: This implementation method is different from any one of specific implementation methods 1 to 3 in that: the shape of the high entropy alloy precursor crystal model in step (2) is a square, and the length x, width y, and height z of the model are 20, 30, and 13 respectively.

[0046] Specific implementation method five: This implementation method is different from any one of specific implementation methods one to four in that the relaxation in step (3) is carried out in an NPT ensemble at a temperature of 300K.

[0047] Specific implementation method 6: This implementation method is different from any one of the specific implementation methods 1 to 5 in that: the method of adding a vacuum layer in the z direction in step (4) is: using change_box to change the size of the simulation box, adding

[0048] Specific implementation method seven: The difference between this implementation method and any one of specific implementation methods one to six is ​​that the coordinates of the center of the sphere in step (5) are x, y, z, and x, y, z are 35, 17, and 80 respectively.

[0049] Specific implementation eight: This implementation differs from any one of the specific implementations one to seven in that: the radius of the sphere in step (5) is

[0050] Specific embodiment 9: This embodiment differs from any one of the specific embodiments 1 to 8 in that the thickness of the boundary portion in step (6) is The thickness of the piece is the remaining part of the precursor crystal model thickness minus the boundary part.

[0051] Specific implementation method ten: The difference between this implementation method and any one of specific implementation methods one to nine is that the downward pressure parameters in step (10) include: the speed in the z direction of the movement speed is -1, the speeds in the x and y directions are both 0, and the diamond tool is not subjected to force under the nve ensemble.

[0052] Example 1

[0053] The molecular dynamics simulation calculation method for the grinding of FeNiCrCoAl high entropy alloy in this embodiment is carried out according to the following steps:

[0054] (1) Basic parameter setting: Use lammps to build a model and set up the simulation environment;

[0055] The simulation environment includes the unit, spatial dimension, boundary conditions, atom type, simulation time step and atomic neighbor parameters of the simulation system;

[0056] The unit of the simulation system is metal; the spatial dimension is 3; the boundary condition is ppp; that is, the boundaries in the x, y, and z directions are periodic; the atom type is atomic; the simulation time step is 0.001; and the atomic neighbor parameter is 2bin;

[0057] (2) Model establishment: The Fe atomic unit cell with fcc structure is used to establish the high entropy alloy precursor crystal model; there are five types of atoms in the high entropy alloy precursor crystal model, namely Fe, Ni, Cr, Co, and Al; iron atoms are first filled in the model area, and then the atomic replacement command settype / ratio is used to randomly replace the iron atoms with Ni, Cr, Co, and Al atoms according to the atomic percentage to obtain the Fe, Ni, Cr, Co, and Al high entropy alloy models, and the relative atomic mass of each atom is set;

[0058] The atomic percentages of Fe, Ni, Cr, Co, and Al in the precursor crystal model are 1:1:1:1:1, respectively;

[0059] The high entropy alloy precursor crystal model is in the shape of a square, and the length x, width y, and height z of the model are 20, 30, and 13 respectively; Figure 1 The precursor crystal phase model of the amorphous model established in Example 1 has a fcc structure;

[0060] (3) Minimize and relax the precursor crystal model:

[0061] The relaxation is carried out in the NPT ensemble at a temperature of 300 K;

[0062] (4) Add a vacuum layer in the z direction;

[0063] The method of adding a vacuum layer in the z direction is: use change_box to change the size of the simulation box, and add

[0064] (5) Diamond tool modeling: Use the region sphere command to set the diamond tool region as a spherical region, that is, the diamond tool is a sphere, set the coordinates of the sphere center and the sphere radius, then fill C atoms in the spherical region and write the atomic mass of C;

[0065] The coordinates of the center of the sphere are x, y, and z, and x, y, and z are 35, 17, and 80 respectively;

[0066] The radius of the sphere is

[0067] (6) The high entropy alloy precursor crystal model is divided into two parts, namely the boundary part with a fixed bottom and the piece part where the atoms can move; the thickness of the boundary part is The thickness of the piece part is the remaining part of the precursor crystal model thickness minus the boundary part;

[0068] (7) Calculate the piece layer temperature;

[0069] (8) Fix the atoms in the boundary part. The atoms in the boundary part are always subjected to 0 force and 0 speed during the entire grinding process. Figure 2 The model of the bottom boundary layer (boundary) and the upper atomic layer (piece) fixed to the model;

[0070] (9) Potential function adopts alloy system tersoff / eam / alloy / lj / cut mixed potential;

[0071] (10) Pressing down the diamond tool and defining the pressing parameters of the diamond tool;

[0072] The downward pressure parameters include: the speed in the z direction is -1, the speed in the x and y directions are both 0, and the diamond tool is not subjected to force in the nve ensemble;

[0073] (11) Calculate the friction force of the piece layer: sum the friction forces of all atoms in the x, y, and z directions respectively, with the displacement step number being 1000, and save the friction force to a file;

[0074] (12) Use variable xcm(ball,x) to calculate the coordinates of the center of gravity of the ball, and use fix move transrot to rub the diamond tool in a straight line in the y direction while the diamond tool itself rotates;

[0075] (13) Run the grinding process and save the file. The resulting file is displayed in Ovito and a stress contour map is drawn. Figure 3 This is a model diagram of the grinding process of Example 1; Figure 4 This is the stress distribution cloud diagram of the grinding process in Example 1. Figure 3 The movement of atoms during the entire grinding process can be observed. Figure 4 The different colors of atoms indicate the stress distribution and stress concentration at the atom.

[0076] This embodiment can realize the dynamic simulation of the whole process of high entropy alloy friction. The molecular dynamics simulation can reveal the influence of the distribution of different elements in the alloy on the friction coefficient and surface wear, and predict the evolution of material deformation, interface shear and surface morphology during the friction process. Figure 3 Observing the movement trajectory of surface atoms during friction can reveal the atomic shedding and surface reconstruction process when the alloy surface is worn. Elements with higher strength (such as aluminum) in the alloy can improve the wear resistance of the alloy and reduce the friction coefficient. By simulating the segregation of elements during the process, it is possible to analyze how different elements affect the mechanical properties and friction characteristics of the alloy. Figure 4 Analyzing the stress-strain response of alloys under friction can predict the deformation behavior of materials. For example, dislocation movement and stress concentration between atoms can be used to optimize the surface treatment method and interface design of high-entropy alloys, and improve the friction characteristics and wear resistance of high-entropy alloys in specific engineering applications. This optimized design can effectively extend the service life of the material, improve its working efficiency, and explore the application potential of new high-entropy alloys in different engineering fields.

Claims

1. A molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy, characterized by: The molecular dynamics simulation calculation method for FeNiCrCoAl high entropy alloy grinding is carried out according to the following steps: (1) Basic parameter setting: Use lammps to build a model and set up the simulation environment; The simulation environment includes the unit, spatial dimension, boundary conditions, atom type, simulation time step and atomic neighbor parameters of the simulation system; (2) Model establishment: The Fe atomic unit cell with fcc structure is used to establish the high entropy alloy precursor crystal model; there are five types of atoms in the high entropy alloy precursor crystal model, namely Fe, Ni, Cr, Co, and Al; iron atoms are first filled in the model area, and then the atomic replacement command settype / ratio is used to randomly replace the iron atoms with Ni, Cr, Co, and Al atoms according to the atomic percentage to obtain the Fe, Ni, Cr, Co, and Al high entropy alloy models, and the relative atomic mass of each atom is set; (3) Minimize and relax the precursor crystal model: (4) Add a vacuum layer in the z direction; (5) Diamond tool modeling: Use the region sphere command to set the diamond tool region as a spherical region, that is, the diamond tool is a sphere, set the coordinates of the sphere center and the sphere radius, then fill C atoms in the spherical region and write the atomic mass of C; (6) The high entropy alloy precursor crystal model is divided into two parts, namely the boundary part with a fixed bottom and the piece part where atoms can move; (7) Calculate the piece layer temperature; (8) Fix the atoms in the boundary part. The atoms in the boundary part are always subjected to 0 force and 0 speed during the entire grinding process. (9) Potential function adopts alloy system tersoff / eam / alloy / lj / cut mixed potential; (10) Pressing down the diamond tool and defining the pressing parameters of the diamond tool; (11) Calculate the friction force of the piece layer: sum the friction forces of all atoms in the x, y, and z directions respectively, with the displacement step number being 1000, and save the friction force to a file; (12) Use variable xcm(ball,x) to calculate the coordinates of the center of gravity of the ball, and use fix move transrot to rub the diamond tool in a straight line in the y direction while the diamond tool itself rotates; (13) Run the grinding process and save the file. The resulting file is displayed in Ovito and a stress contour map is drawn.

2. The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy according to claim 1, characterized in that: The unit of the simulation system in step (1) is metal; the spatial dimension is 3; the boundary condition is ppp; that is, the boundaries are periodic in the x, y, and z directions; the atom type is atomic; the simulation time step is 0.001; and the atomic neighbor parameter is 2bin.

3. The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy according to claim 1, characterized in that: The atomic percentages of Fe, Ni, Cr, Co and Al in the precursor crystal model of step (2) are 1:1:1:1:1 respectively.

4. The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy according to claim 1, characterized in that: The shape of the high entropy alloy precursor crystal model in step (2) is a square, and the length x, width y, and height z of the model are 20, 30, and 13 respectively.

5. The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy according to claim 1, characterized in that: The relaxation in step (3) is carried out in the NPT ensemble at a temperature of 300K.

6. The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy according to claim 1, characterized in that: The method of adding a vacuum layer in the z direction in step (4) is: use change_box to change the size of the simulation box, and add 7. The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy according to claim 1, characterized in that: The coordinates of the center of the sphere in step (5) are x, y, and z, and x, y, and z are 35, 17, and 80 respectively.

8. The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy according to claim 1, characterized in that: The radius of the sphere in step (5) is 9. The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy according to claim 1, characterized in that: The thickness of the boundary portion in step (6) is The thickness of the piece is the remaining part of the precursor crystal model thickness minus the boundary part.

10. The molecular dynamics simulation calculation method for grinding of FeNiCrCoAl high entropy alloy according to claim 1, characterized in that: The downward pressure parameters in step (10) include: the speed in the z direction is -1, the speeds in the x and y directions are both 0, and the diamond tool is not subjected to force under the nve ensemble.

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