Method for exploring performance change of high-entropy alloy in quasi-static loading and dynamic loading

Abstract

The invention relates to the technical field of high-entropy alloy performance, and discloses a method for exploring performance change of a high-entropy alloy in quasi-static loading and dynamic loading, and the method comprises the following steps: model construction: constructing a FeCrNiAl high-entropy alloy model, a model with random grain orientation and a high-entropy grain boundary modified nano columnar polycrystalline copper model by using lamps software; simulating a quasi-static loading process by adopting an MD method, and analyzing quasi-static loading data by utilizing ovito and origin software; dynamic loading simulation is conducted, wherein dynamic loading is simulated through an MD method, and dynamic loading data are analyzed through ovito and origin software; and respectively carrying out uniaxial compression on the constructed model with the random grain orientation by using lamps. According to the method, the influence of single factors such as the element ratio, the strain rate and the temperature on the performance of the FeCrNiAl-series high-entropy alloy is researched, meanwhile, interaction is also considered, and therefore the problem that limitation may be generated due to the fact that the influence of one or more factors is often researched in an existing high-entropy alloy exploration method in an isolated mode is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of high entropy alloy performance, and specifically to a method for exploring performance changes of high entropy alloys during quasi-static loading and dynamic loading. Background Art

[0002] High entropy alloy is a new type of alloy material. In terms of composition, it is composed of five or more main elements, and the atomic percentage of each element is between 5% and 35%. Unlike traditional alloys, traditional alloys generally have one or two elements as the main components, and the remaining elements are secondary additives, while high entropy alloys break this convention. In terms of performance, high entropy alloys have many excellent properties. It has high strength and hardness, which makes it not easy to deform even when subjected to large external forces. For example, in some mechanical structures that require high material strength, high entropy alloys can play an important role. At the same time, high entropy alloys also have good corrosion resistance. In harsh chemical environments or humid environments, it can effectively resist corrosion and has a longer service life than many traditional alloys. In terms of application fields, high entropy alloys have great potential. In the field of aerospace, its light weight and high strength can be used to manufacture aircraft engine parts, which helps to reduce aircraft weight and improve fuel efficiency. In the automotive industry, high entropy alloys can be used to manufacture high-temperature components of automobile engines or body structural parts to improve the overall performance and safety of automobiles. In short, high entropy alloy, as an emerging material, provides new possibilities for material selection in many industries.

[0003] Existing methods for exploring high-entropy alloys often isolate the effects of one or several factors on the properties of high-entropy alloys and lack a comprehensive multi-factor systematic study, which may lead to limitations in the results. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for exploring the performance changes of high entropy alloys under quasi-static loading and dynamic loading, which solves the problem that the existing methods for exploring high entropy alloys often isolate the influence of one or several factors on the performance of high entropy alloys and lack a comprehensive systematic study of multiple factors, which may lead to limitations in the results.

[0005] To achieve the above objectives, the present invention is implemented by the following technical scheme: a method for exploring the performance change of high entropy alloys during quasi-static loading and dynamic loading, comprising the following steps:

[0006] S1. Model construction: Use lammps software to construct the FeCrNiAl series high entropy alloy model, the random grain orientation model, and the high entropy grain boundary modified nano-columnar polycrystalline copper model;

[0007] S2. Quasi-static loading simulation: The MD method is used to simulate the quasi-static loading process, and the quasi-static loading data are analyzed using ovito and origin software;

[0008] S3, dynamic loading simulation: MD method is used to simulate dynamic loading, and ovito and origin software are used to analyze dynamic loading data;

[0009] S4. Study on the strength limit of polycrystalline model: uniaxial compression was performed on the constructed model with random grain orientation using lammps;

[0010] S5. Study on the properties of metals modified by high entropy grain boundaries: For the nano-columnar polycrystalline copper model modified by high entropy grain boundaries, relaxation is performed under the NPT ensemble. After the system energy reaches a state of equilibrium, a room temperature tensile simulation is performed under the NVT ensemble.

[0011] S6. Element substrate research: Using Fe and Al as substrate elements, HEA@Fe and HEA@Al models with high entropy of grain boundaries are constructed. The ultimate strength and plastic deformation of HEA@Fe and HEA@Al under uniaxial compression are analyzed by drawing the total dislocation line density diagram.

[0012] Preferably, the FeCrNiAl-based high entropy alloy in step S1 includes (FeCr)10(NiAl)90, (FeCr)20(NiAl)80, (FeCr)30(NiAl)70 and (FeCr)40(NiAl)60.

[0013] Preferably, the model with random grain orientation in step S1 includes polycrystalline Fe, polycrystalline Cr, polycrystalline Ni and polycrystalline Al models.

[0014] Preferably, the loading method in step S3 includes fix move and velocity methods.

[0015] Preferably, in step S3, the dynamic loading data is loaded through strain rate speeds of 1 km / s, 1.5 km / s, 2 km / s, and 2.5 km / s respectively.

[0016] Preferably, in step S3, the dynamic loading data is impacted on the FeCrNiAl series high entropy alloy model under the condition of temperature ranging from 1K to 600K.

[0017] Preferably, the ovito and origin software are used to draw stress-strain diagrams, CAN diagrams, slip vector diagrams and shear strain diagrams.

[0018] Preferably, the stretching simulation in step S5 is to apply a stretching speed on a fixed layer with a thickness of 1 nm at both ends of the model along the Y axis, and the simulation time is 50 ps.

[0019] The present invention provides a method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading. It has the following beneficial effects:

[0020] 1. In the present invention, the influence of single factors such as element ratio, strain rate, temperature, etc. on the performance of FeCrNiAl series high entropy alloys is studied, and the interaction between different factors is also comprehensively considered. When studying the dynamic mechanical properties, the comprehensive influence of element combination ratio and strain rate is simultaneously analyzed, so as to grasp the alloy performance change mechanism more comprehensively, thereby improving the existing methods for exploring high entropy alloys, which often study the influence of one or several factors on the performance of high entropy alloys in isolation, lack a comprehensive systematic study of multiple factors, and may therefore result in the problem of limited results.

[0021] 2. In the present invention, by constructing polycrystalline Fe, Cr, Ni, and Al models with random grain orientation, the influence of different strain rates on their strength limit is studied; a nano-columnar polycrystalline copper model modified with high entropy grain boundaries is constructed to study the influence on the tensile mechanical properties and crack propagation behavior of common metals; HEA@Fe and HEA@Al models with high entropy grain boundaries are also constructed to study their strength limit and plastic deformation behavior, expanding the research scope of high entropy alloy properties from multiple dimensions.

[0022] 3. In the present invention, after comprehensive use of the MD method for simulation, origin and ovito software are used to visualize the data, and various graphs such as stress-strain curves, CNA graphs, shear strain graphs, and slip vector graphs are drawn. The effects of different loading methods, speeds, and element ratios on the properties of high-entropy alloys are deeply analyzed from multiple angles, which enhances the intuitiveness of the results and the depth of analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Please see attached Figure 1 The embodiment of the present invention provides a method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading, which is characterized by comprising the following steps:

[0026] S1. Model construction: Use lammps software to construct the FeCrNiAl series high entropy alloy model, the random grain orientation model, and the high entropy grain boundary modified nano-columnar polycrystalline copper model;

[0027] S2. Quasi-static loading simulation: The MD method is used to simulate the quasi-static loading process, and the quasi-static loading data are analyzed using ovito and origin software;

[0028] S3, dynamic loading simulation: MD method is used to simulate dynamic loading, and ovito and origin software are used to analyze dynamic loading data;

[0029] S4. Study on the strength limit of polycrystalline model: uniaxial compression was performed on the constructed model with random grain orientation using lammps;

[0030] S5. Study on the properties of metals modified by high entropy grain boundaries: For the nano-columnar polycrystalline copper model modified by high entropy grain boundaries, relaxation is performed under the NPT ensemble. After the system energy reaches a state of equilibrium, a room temperature tensile simulation is performed under the NVT ensemble.

[0031] S6. Element substrate research: Using Fe and Al as substrate elements, HEA@Fe and HEA@Al models with high entropy of grain boundaries are constructed. The ultimate strength and plastic deformation of HEA@Fe and HEA@Al under uniaxial compression are analyzed by drawing the total dislocation line density diagram.

[0032] Specifically, by using lammps software to construct these models, it can provide a basis for studying the mechanical properties of high entropy alloys under quasi-static and dynamic loading, the influence of element ratio on performance, polycrystalline element characteristics, and grain boundary modification effects, thereby providing a theoretical basis and optimization direction for the application of high entropy alloys in multiple fields;

[0033] The dynamic mechanical properties of FeCrNiAl high entropy alloy samples with different element composition ratios were tested at different strain rates using Hopkinson pressure bar equipment. The dynamic failure process of the materials was recorded using high-speed photography and DIC equipment. The microstructure information of the samples was observed using SEM, and the change law of their dynamic mechanical properties was experimentally analyzed.

[0034] The MD method was used to simulate two sets of theoretical experiments, and three loading methods were used: fix move, velocity, and deform. By analyzing and comparing the stress-strain curves obtained by the three methods, it was found that the deform method was too idealized and there was no crushing process, so the fix move and velocity methods were selected as subsequent loading methods. After determining the appropriate loading method, formal theoretical experiments were started. The first group selected different element ratios at the same strain rate, and the second group selected different strain rates at the same element ratio. Both groups drew stress-strain curves through data visualization, conducted horizontal and vertical comparisons, and analyzed the stress-strain diagrams to present the results. Finally, the dynamic mechanical properties experimental results were compared to reveal the influence of element combination ratios and strain rates on the dynamic mechanical properties of FeCrNiAl high entropy alloys;

[0035] While studying the four polycrystalline elements, it was found that Fe has excellent dynamic mechanical properties, so Fe was used as the base element to construct Fe@HEA with high entropy at the grain boundary, using the base metal plus grain boundary modification method to improve the performance of the material while saving costs. The effects of different strain rates on the strength limit of high entropy alloys and the plastic deformation behavior of high entropy alloys under uniaxial compression were studied.

[0036] The FeCrNiAl-based high entropy alloy in step S1 includes (FeCr)10(NiAl)90, (FeCr)20(NiAl)80, (FeCr)30(NiAl)70 and (FeCr)40(NiAl)60.

[0037] Specifically, by selecting FeCrNiAl high-entropy alloys with specific ratios for research, it is helpful to compare the effects of different element ratios on the quasi-static and dynamic mechanical properties of the alloys, thereby providing basic data for revealing the influence of element combination ratios and strain rate on alloy properties, and providing performance reference for its application in multiple fields.

[0038] The models with random grain orientation in step S1 include polycrystalline Fe, polycrystalline Cr, polycrystalline Ni and polycrystalline Al models.

[0039] Specifically, by constructing models of polycrystalline Fe, polycrystalline Cr, polycrystalline Ni and polycrystalline Al, we can comprehensively explore the variation law of the strength limit of different polycrystalline elements under uniaxial compression, compare their mechanical properties, and provide a basis for screening high-performance substrate elements. At the same time, it helps to deeply understand the mechanical behavior characteristics of polycrystalline materials and lay the foundation for the research of high-entropy alloys.

[0040] The loading methods in step S3 include fixmove and velocity methods.

[0041] Specifically, by using the fixmove and velocity methods for loading in step S3, the mechanical behavior of FeCrNiAl high entropy alloys under dynamic loading can be accurately simulated, the influence of strain rate on the dynamic mechanical properties of the alloy can be effectively analyzed, and the performance differences of alloys with different element ratios can be compared, thereby providing a reliable basis for revealing the law of change of the dynamic mechanical properties of the alloy and facilitating the application of high entropy alloys in practical engineering.

[0042] In step S3, the dynamic loading data is passed through strain rate speeds of 1Km / s, 1.5Km / s, 2Km / s, and 2.5Km / s respectively.

[0043] Specifically, by using a specific strain rate to conduct dynamic loading data testing, we can systematically analyze the influence of strain rate on the dynamic mechanical properties of FeCrNiAl high-entropy alloys, compare the performance changes of alloys with different element ratios, and provide key data support for optimizing alloy composition and engineering applications.

[0044] In step S3, the dynamic loading data impacts the FeCrNiAl high entropy alloy model under the condition of temperature ranging from 1K to 600K.

[0045] Specifically, by impacting the FeCrNiAl high-entropy alloy model under temperature conditions of 1K to 600K to obtain dynamic loading data, we can comprehensively explore the influence of temperature on the dynamic mechanical properties of the alloy, clarify the effect of different temperature ranges on the strength limit of the alloy, and provide a theoretical basis and performance reference for the application of the alloy under different temperature environments, which will help the optimized design and reliable application of high-entropy alloys in multiple fields.

[0046] The research results of FeCrNiAl high entropy alloys with the same element ratio show that with the increase of FeCr element content, the strength limit of the model increases accordingly; the strength limit of each element ratio increases with the increase of strain rate; and the effect of temperature on the strength limit depends on the set temperature range. Within a certain range (1K to 200K), the alloy strength limit increases with the increase of temperature. When the temperature reaches 100K and above, the temperature has little effect on the strength limit.

[0047] The research results of polycrystalline Fe, polycrystalline Ce, polycrystalline Ni and polycrystalline Al show that the strength limit of the four polycrystalline models will increase with the increase of strain rate, and the corresponding strain when reaching the strength limit will decrease with the increase of strain rate. It is worth noting that Fe has excellent mechanical properties and low cost.

[0048] Ovito and origin software are used to draw stress-strain diagrams, CAN diagrams, slip vector diagrams and shear strain diagrams.

[0049] Specifically, Ovito and Origin software play a key role in drawing a variety of graphics. They can intuitively present the mechanical properties and microstructural changes of FeCrNiAl high-entropy alloys under different loading conditions, deeply analyze the influencing factors, and provide strong support for optimizing alloy properties and engineering applications. By drawing the co-occurrence analysis (CNA) diagram, shear strain diagram, and slip vector diagram of the three states of elastic limit, strength limit, and necking of the material, the causes are analyzed and inferred, and then the influence of element ratio on the quasi-static mechanical properties of FeCrNiAl high-entropy alloys is obtained.

[0050] The stretching simulation in step S5 is to apply a stretching velocity on a fixed layer with a thickness of 1 nm at both ends of the model along the Y axis, and the simulation time is 50 ps.

[0051] Specifically, by applying a tensile velocity on a 1nm thick fixed layer at both ends of the model along the Y axis and setting the simulation time to 50ps for tensile simulation, the tensile mechanical behavior of nano-columnar polycrystalline copper modified with high entropy grain boundaries under specific conditions can be accurately simulated, and the influence of grain boundary modification on its performance can be deeply analyzed, providing an important basis for optimizing material performance and expanding applications.

[0052] When the FeNiCrCoCu high entropy alloy is subjected to tension, the elastic modulus and peak stress are much greater than those of the polycrystalline copper without grain boundary modification and high entropy grain boundary modification. The peak stress and yield strength of the polycrystalline copper modified with high entropy grain boundary are greatly improved compared with the peak stress and yield limit of the polycrystalline copper without grain boundary modification. In the polycrystalline copper modified with high entropy grain boundary, the crack length is less than The tensile behavior when the crack is not formed is close to that when the crack is not formed. When the crack length increases, the peak stress and yield strength of the high entropy grain boundary modified polycrystalline copper decrease with the increase of crack length. The degree of this decrease is more obvious than that of the polycrystalline copper without high entropy grain boundary modification under tension. The strain corresponding to the peak stress of the high entropy grain boundary modified polycrystalline copper and the unmodified polycrystalline copper is almost the same, both of which are 0.078.

[0053] The crack growth rate of high-entropy grain boundary modified polycrystalline copper is faster than that of nano-columnar polycrystalline copper, and there is a significant difference in the crack growth evolution. The crack growth of high-entropy grain boundary modified polycrystalline copper is mainly driven by grain boundary sliding, so that its growth proceeds along the "X-type" shear band direction, while the crack growth of nano-columnar polycrystalline copper is composed of both grain dislocation and grain boundary sliding.

[0054] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading, characterized in that: The following steps are involved: S1. Model construction: Use lammps software to construct the FeCrNiAl series high entropy alloy model, the random grain orientation model, and the high entropy grain boundary modified nano-columnar polycrystalline copper model; S2. Quasi-static loading simulation: The MD method is used to simulate the quasi-static loading process, and the quasi-static loading data are analyzed using ovito and origin software; S3, dynamic loading simulation: MD method is used to simulate dynamic loading, and ovito and origin software are used to analyze dynamic loading data; S4. Study on the strength limit of polycrystalline model: uniaxial compression was performed on the constructed model with random grain orientation using lammps; S5. Study on the properties of metals modified by high entropy grain boundaries: For the nano-columnar polycrystalline copper model modified by high entropy grain boundaries, relaxation is performed under the NPT ensemble. After the system energy reaches a state of equilibrium, a room temperature tensile simulation is performed under the NVT ensemble. S6. Element substrate research: Using Fe and Al as substrate elements, HEA@Fe and HEA@Al models with high entropy of grain boundaries are constructed. The ultimate strength and plastic deformation of HEA@Fe and HEA@Al under uniaxial compression are analyzed by drawing the total dislocation line density diagram.

2. The method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading according to claim 1, characterized in that: The FeCrNiAl high entropy alloy in step S1 includes (FeCr)10(NiAl)90, (FeCr)20(NiAl)80, (FeCr)30(NiAl)70 and (FeCr)40(NiAl)60.

3. The method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading according to claim 1, characterized in that: The models with random grain orientation in step S1 include polycrystalline Fe, polycrystalline Cr, polycrystalline Ni and polycrystalline Al models.

4. The method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading according to claim 1, characterized in that: The loading methods in step S3 include fix move and velocity methods.

5. The method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading according to claim 1, characterized in that: In the step S3, the dynamic loading data is loaded through strain rate speeds of 1 Km / s, 1.5 Km / s, 2 Km / s, and 2.5 Km / s respectively.

6. The method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading according to claim 1, characterized in that: In step S3, the dynamic loading data is impacted on the FeCrNiAl series high entropy alloy model under the condition of temperature ranging from 1K to 600K.

7. The method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading according to claim 1, characterized in that: The ovito and origin software are used to draw stress-strain diagrams, CAN diagrams, slip vector diagrams and shear strain diagrams.

8. The method for exploring the performance changes of high entropy alloys during quasi-static loading and dynamic loading according to claim 1, characterized in that: The stretching simulation in step S5 is to apply a stretching speed on a fixed layer with a thickness of 1 nm at both ends of the model along the Y axis, and the simulation time is 50 ps.

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