Screening method of high-toughness binary non-ferrous metal alloy

Abstract

The invention discloses a method for screening a high-toughness binary nonferrous metal alloy. The method comprises the following steps: constructing a supercell matrix model of nonferrous metal by utilizing modeling software; an element replacement method is adopted, different kinds of alloy atoms are used for replacing part of atoms in the nonferrous metal supercell matrix, and a solid solution model of multiple alloy elements to the metal matrix is constructed; carrying out sufficient structural relaxation on the solid solution model by utilizing first principle calculation software, and calculating formation energy of the solid solution model; calculating the elastic constant of the solid solution model by using a stress-strain method, judging the mechanical stability of the solid solution model, calculating the bulk modulus, the shear modulus, the Young modulus and the ratio of the bulk modulus to the shear modulus of each solid solution model, and screening the binary non-ferrous metal alloy with high stability, high elastic modulus and high toughness by contrastive analysis; the method is provided for production and design of the novel non-ferrous metal-based alloy, and the research and development period and cost are effectively shortened.

Description

Technical Field

[0001] The invention relates to the field of high-tech materials for aviation structures or biomedicine, and in particular to a theoretical method for measuring the solid solution strengthening effect of alloy elements on non-ferrous metal matrices, and belongs to the field of new structural material design. Background Art

[0002] Nonferrous metal alloys have a wide range of uses and have been widely used in aerospace structures, biomedicine, machinery manufacturing, automobiles and other fields. In recent years, the output of nonferrous metal alloys in my country has continued to grow, especially driven by emerging industries such as new energy and electronic information, and market demand has continued to expand. However, my country's nonferrous metal materials industry still has certain shortcomings in terms of high value-added products, reduced energy consumption, and sustainable development. Traditional nonferrous metals are usually low in strength and cannot adapt to the increasingly harsh use environment. Therefore, it is extremely important to try to improve the strength of nonferrous metals and develop new nonferrous metal structural materials with high specific strength and high specific stiffness.

[0003] At present, there are many methods for strengthening nonferrous metals, and commonly used ones include solid solution strengthening, fine grain strengthening, precipitation strengthening, and heat treatment strengthening. Solid solution strengthening plays a very important role in the design of high-strength nonferrous metal alloys. According to the solid solution theory, a variety of elements can be dissolved into the nonferrous metal matrix and form a solid solution. However, solid solution strengthening requires that the solid solution atoms replace the matrix atoms or embed into the lattice without changing the matrix structure. At present, the experimental process of solid solution nonferrous alloys is cumbersome and costly, and it is impossible to explore the origin of solid solution strengthening from the atomic scale. At present, the development of solid solution strengthening in nonferrous metal matrices is not in-depth enough, and the application of solid solution strengthening in various nonferrous alloys has not achieved very significant results. The huge potential of solid solution strengthening has not been fully realized. Summary of the invention

[0004] In view of the above problems, the present invention aims to provide a method for screening high-strength and high-toughness binary nonferrous metal alloys, wherein the method comprises the following steps: (1) Model construction: a. Construct nonferrous metal supercell matrix model using VESTA software; b. Select a variety of doping elements and construct a unit cell model of each doping element in its pure state using VESTA software; c. Using the element replacement method, using the doping element atoms involved in step (1) b to replace some atoms in the non-ferrous metal supercell matrix model constructed in step (1) a, constructing a solid solution model of multiple elements in the non-ferrous metal supercell matrix; (2) Simulation calculation: a. Using Quantum Espresso software, perform structural relaxation on the structural models obtained in step (1) a, step (1) b, and step (1) c, respectively, and perform self-consistent calculation to extract the total energy after structural relaxation to obtain the ground state structure data file of each solid solution model as the input file for the next step of elastic constant calculation; b. Using Quantum Espresso software, calculate the elastic constants of each solid solution model obtained in step (2) a; (3) Result processing and analysis: Using the energy data obtained in step (2) a, calculate the formation energy of each solid solution model and eliminate the models with formation energy greater than 0; Using the elastic constants obtained in step (2) b, the mechanical stability of each solid solution model is analyzed and judged with the help of Born's mechanical stability criterion, and unstable solid solution models are eliminated; The bulk modulus, shear modulus, Young's modulus and the ratio of bulk modulus to shear modulus of each solid solution model were calculated using the Vogit-Ruess-Hill method. Through comprehensive screening of formation energy and elastic modulus, a binary nonferrous metal alloy with high stability, high elastic modulus and high toughness was obtained.

[0005] Preferably, the scale range of the supercell model of the metal matrix is ​​2*2*2~4*4*4.

[0006] Preferably, the content of dissolved atoms in the solid solution model is not higher than 5 at. %.

[0007] Preferably, solid solution models with a ratio of bulk modulus to shear modulus less than 1.75 are eliminated during the screening process.

[0008] Preferably, in the calculation of elastic constants using Quantum Espresso software, the strain energy-strain method is used to apply a series of small strains to the solid solution model, extract the structural energy data after applying different strains, and calculate the elastic constants of each solid solution model.

[0009] The advantages of the present invention are: the present invention provides a screening method for high-strength and tough binary nonferrous metal alloys for the first time, and the screening results can provide direction for experimental preparation and promote the development of new structural materials. In addition, the present method is completed by first-principles calculation simulation, without any experiments, which can greatly shorten the material design cycle and save time and cost. The method is also easy to operate, low cost, clean and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0011] Figure 1 It is a technical route flow chart for specific research; Figure 2 are the bulk modulus, shear modulus, Young's modulus, and the ratio of the bulk modulus to the shear modulus. DETAILED DESCRIPTION

[0012] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are 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.

[0013] In order to make the purpose and technical solution of the present invention clearer, the following takes binary Mg alloy as an example to further understand the technical solution and advantages of the present invention. The specific calculation process is as follows: Figure 1 shown. Example

[0014] (1) Model construction: a. Construct a 3*3*3 supercell model of pure Mg metal matrix using VESTA software; b. Select Tb, Dy, Ho, and Er as doping elements, and construct the unit cell models of the single element state of the doping elements Tb, Dy, Ho, and Er respectively by using VESTA software; c. If Figure 2 As shown, the element replacement method is used to replace some atoms in the non-ferrous metal supercell matrix model constructed in step (1) a with Tb, Dy, Ho, and Er element atoms, and a 3.7 at.% solid solution model of a pure Mg metal matrix containing multiple Tb, Dy, Ho, and Er elements is constructed; (2) Simulation calculation: a. Using the first-principles calculation software Quantum Espresso, the cutoff energy in the calculation is 40 Ry, the K-point grid density is selected as 5*5*5, the broadening method is selected as gaussian, and the ion step limit is set to 300. The 3*3*3 supercell model of the pure Mg metal matrix obtained in step (1) a, step (1) b, and step (1) c, the single cell model of the single element state of Tb, Dy, Ho, and Er elements, and the 3.7 at.% solid solution model of the pure Mg metal matrix of Tb, Dy, Ho, and Er elements are structurally relaxed by Quantum Espresso software, and after structural relaxation, a self-consistent calculation is performed to extract the total energy, and the ground state structure data file of each solid solution model is obtained as the input file for the next step of elastic constant calculation; b. Using the Quantum Espresso software and the strain energy-strain method, a series of small strains are applied to the solid solution model, and the structural energy data after applying different strains are extracted, and the elastic constants of the ground state structure of each solid solution model obtained in step (2) a are calculated respectively; Result processing and analysis: a. Using the energy data obtained in step (2) a, calculate the formation energy of each solid solution model and eliminate the model with a formation energy greater than 0; b. Using the elastic constant matrix obtained in the previous step, the Born mechanical stability criterion is used to analyze and judge the mechanical stability of each solid solution model, and the unstable solid solution model is eliminated; c. If Figure 2 As shown, the bulk modulus, shear modulus, Young's modulus and the ratio of bulk modulus to shear modulus of each solid solution model are calculated using the Vogit-Ruess-Hill method; d. Through comprehensive screening of formation energy and elastic modulus, it was found that the Mg matrix with Er element solid solution has high stability and high elastic modulus and high toughness. It was screened that Mg-Er is a highly potential high-strength and high-toughness binary non-ferrous metal alloy.

Claims

1. A method for screening high-strength and high-toughness binary nonferrous metal alloys, characterized in that: The method comprises the following steps: (1) Model construction: a. Construct nonferrous metal supercell matrix model using VESTA software; b. Select a variety of doping elements and construct a unit cell model of each doping element in its pure state using VESTA software; c. Using the element replacement method, using the doping element atoms involved in step (1) b to replace some atoms in the non-ferrous metal supercell matrix model constructed in step (1) a, constructing a solid solution model of multiple elements in the non-ferrous metal supercell matrix; (2) Simulation calculation: a. Using Quantum Espresso software, perform structural relaxation on the structural models obtained in step (1) a, step (1) b, and step (1) c, respectively, and perform self-consistent calculation to extract the total energy after structural relaxation to obtain the ground state structure data file of each solid solution model as the input file for the next step of elastic constant calculation; b. Using Quantum Espresso software, calculate the elastic constants of each solid solution model obtained in step (2) a; (3) Result processing and analysis: Using the energy data obtained in step (2) a, calculate the formation energy of each solid solution model and eliminate the models with formation energy greater than 0; Using the elastic constants obtained in step (2) b, the mechanical stability of each solid solution model is analyzed and judged with the help of Born's mechanical stability criterion, and unstable solid solution models are eliminated; The bulk modulus, shear modulus, Young's modulus and the ratio of bulk modulus to shear modulus of each solid solution model were calculated using the Vogit-Ruess-Hill method. Through comprehensive screening of formation energy and elastic modulus, a binary nonferrous metal alloy with high stability, high elastic modulus and high toughness was obtained.

2. A method for screening high-strength and high-toughness binary nonferrous metal alloys as claimed in claim 1, characterized in that The scale of the supercell model of the metal matrix ranges from 2*2*2 to 4*4*4.

3. The method for screening a high-strength and high-toughness binary nonferrous metal alloy according to claim 1, characterized in that The content of dissolved atoms in the solid solution model is not higher than 5 at. %.

4. A method for screening high-strength and high-toughness binary nonferrous metal alloys as claimed in claim 1, characterized in that During the screening process, solid solution models with a ratio of bulk modulus to shear modulus less than 1.75 were eliminated.

5. The method for screening a high-strength and high-toughness binary nonferrous metal alloy according to claim 1, characterized in that In the calculation of elastic constants using Quantum Espresso software, the strain energy-strain method is used to apply a series of small strains to the solid solution model, extract the structural energy data after applying different strains, and calculate the elastic constants of each solid solution model.

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