Solid solution limit calculation method, solid solution limit calculation apparatus, solid solution limit calculation system, program

Abstract

To provide a solid solubility limit computation method which enables computation of a solid solubility limit of a substitution element in a base material.SOLUTION: A solid solubility limit computation method is provided, comprising a phase boundary computation step of using information on a target base material and a substitution element to derive a phase boundary between the base material and a crystal phase closest to the base material in a phase diagram of the base material and the substitution element, and a solid solubility limit computation step of deriving a solid solubility limit of the substitution element in the base material based on the phase boundary derived in the phase boundary computation step.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a solid solubility limit calculation method, a solid solubility limit calculation device, a solid solubility limit calculation system, and a program.

Background Art

[0002] A solid solution in which a certain element contained in a base material is substituted with another element may exhibit properties superior to those of the unsubstituted base material, and is important in various fields such as structural materials, catalyst materials, and functional materials including superconducting materials.

[0003] Whether a certain element forms a solid solution in a base material can be determined from a phase diagram. Taking the binary phase diagram of substance A and substance B shown in Figure 1 as an example, it can be seen that the solid solubility limit of substance B in substance A at temperature T' is X%.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] It is possible to read the solid solubility limit of a substitution element in a base material from a phase diagram. However, a phase diagram for the base material and the substitution element contained in the solid solution to be produced is not always already available. In such cases, since the solid solubility limit is unknown, trial production at concentrations that do not actually form a solid solution cannot be avoided, resulting in enormous costs for material development.

[0006] Therefore, in view of the problems of the above-mentioned prior art, one aspect of the present invention aims to provide a method for calculating the solid solubility limit of a substitution element in a parent material. [Means for solving the problem]

[0007] To solve the above problems, according to one aspect of the present invention, A phase boundary calculation step calculates the phase boundary between the target parent material and the crystalline phase closest to the parent material when the parent material and the substituted element are represented as a phase diagram, based on information about the target parent material and the substituted element. The process includes a solid solution limit calculation step, which calculates the solid solution limit of the substitution element in the mother material from the phase boundary obtained in the phase boundary calculation step. fruit, The aforementioned phase boundary calculation step is: A convex hull creation step, in which a convex hull is created with the parent substance and the substituted element as its ends by first-principles calculation using a genetic algorithm, An extraction step in which the crystalline phase closest to the parent material is extracted using the aforementioned convex hull, A free energy calculation step for the parent material and the crystalline phase closest to the parent material, in which the free energy is calculated when the amount of substitution by the substitution element is changed, The calculation step includes, for the parent material and the crystalline phase closest to the parent material, calculated in the free energy calculation step, a calculation step that calculates the phase boundary from the free energy when the amount of substitution by the substitution element is changed. This document provides a method for calculating the solid solubility limit. [Effects of the Invention]

[0008] According to one aspect of the present invention, a method for calculating the solid solubility limit of a substitution element in a parent material can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an example of a phase diagram. [Figure 2] Figure 2 is a flowchart of a method for calculating the solid solution limit according to one aspect of the present disclosure. [Figure 3] Figure 3 is a flowchart of the phase boundary calculation process. [Figure 4] Figure 4 is an illustrative diagram of the convex hull. [Figure 5] Figure 5 is an explanatory diagram of the operations in the phase boundary calculation process. [Figure 6] FIG. 6 is a hardware configuration diagram of a solid solubility limit calculation apparatus according to one aspect of the present disclosure. [Figure 7] FIG. 7 is a block diagram illustrating functions of the solid solubility limit calculation apparatus according to one aspect of the present disclosure. [Figure 8] FIG. 8 is an explanatory diagram illustrating a configuration of a phase boundary calculation unit of the solid solubility limit calculation apparatus according to one aspect of the present disclosure. [Figure 9] FIG. 9 is an explanatory diagram of a solid solubility limit calculation system according to one aspect of the present disclosure. [Mode for Carrying Out the Invention]

[0010] Specific examples of a solid solubility limit calculation method, a solid solubility limit calculation apparatus, a solid solubility limit calculation system, and a program according to an embodiment of the present disclosure (hereinafter referred to as "the present embodiment") will be described below with reference to the drawings. Note that the present invention is not limited to these illustrative examples, is indicated by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. [Solid Solubility Limit Calculation Method] The solid solubility limit calculation method of the present embodiment can be implemented along the flowchart 20 shown in FIG. 2, and can include the following phase boundary calculation step (S21) and solid solubility limit calculation step (S22).

[0011] In the present specification, the solid solution means a solid phase in which the crystal structure remains as that of the base material when a substitutional element is added to the base material to change the chemical composition from that of the base material. The solid solubility limit means the maximum concentration (maximum solubility) at which the substitutional element can be added while the base material maintains the crystal structure before the addition of the substitutional element when the substitutional element is added to the base material.

[0012] Each step is described below. (1) Phase Boundary Calculation Step (S21) In the phase boundary calculation step (S21), a phase boundary between the target base material and the crystal phase closest to the base material in the phase diagram of the base material and the substitutional element is calculated based on information on the target base material and the substitutional element.

[0013] In the phase boundary calculation step (S21), a phase boundary between the base material and the crystal phase closest to the base material (hereinafter also simply referred to as "phase boundary") can be calculated in a phase diagram having the base material and the substitution element as both ends. The phase diagram having the base material and the substitution element as both ends means, for example, in the phase diagram 10 shown in FIG. 1, a phase diagram in which substance A is the base material and substance B is the substitution element. Further, the phase boundary means the boundary between the base material and the crystal phase closest to the base material. The phase boundary obtained in the phase boundary calculation step means information related to the phase boundary, such as the position of the phase boundary on the phase diagram, and points that can be used when calculating the solid solubility limit in the free energy graph shown in FIG. 5 described later. For this reason, the phase boundary obtained in the phase boundary calculation step can also be referred to as phase boundary information or the like.

[0014] As described above, the solid solubility limit is the maximum concentration of the substitution element that can be added while the base material maintains the crystal structure before the addition of the substitution element when the substitution element is added to the base material. Therefore, the solid solubility limit can be obtained by calculating the phase boundary in the phase boundary calculation step, and calculating the concentration of the substitution element that can be dissolved in solid solution up to the relevant phase boundary in the solid solubility limit calculation step described later. The crystal phase closest to the base material has a crystal structure different from that of the base material.

[0015] In the phase boundary calculation step (S21), the specific method for calculating the phase boundary is not particularly limited. The phase boundary calculation step (S21) can be performed, for example, according to the flowchart 30 shown in FIG. 3. The phase boundary calculation step (S21) can include, for example, the following convex hull creation step (S31), extraction step (S32), free energy calculation step (S33), and calculation step (S34). (1-1) Convex hull creation step (S31) In the convex hull formation process (S31), a convex hull can be formed with the parent material and the substitution element at both ends, as shown in Figure 4. A convex hull is a line connecting the most stable crystalline phases that appear when the element to be substituted in the parent material is gradually replaced by the substitution element. For example, in the convex hull shown in Figure 4, there are crystalline phases A6B, A2B, A5B4, and AB between the parent material A and the substitution element B, and the points with the lowest enthalpy of formation are connected by line 41. As shown in Figure 4, the leftmost point in Figure 4 represents the parent material A, and the rightmost point represents the substitution element B.

[0016] A convex hull can be created, for example, by first-principles calculations using a genetic algorithm to determine the enthalpy of formation for various compositions of substances consisting of parent substance A and substituted element B, and then visualizing the calculation results.

[0017] First-principles calculations refer to methods of calculating the motion of electrons in matter using a computer, in accordance with the Schrödinger equation of quantum mechanics. Genetic algorithms refer to algorithms that mimic biological evolution, such as chromosome crossover, mutation, and natural selection.

[0018] In the convex hull fabrication process, for example, a crystal structure model can be created and determined using a genetic algorithm. Then, the enthalpy of formation can be calculated for the determined crystal structure model using first-principles calculations. The creation and determination of the crystal structure model is not limited to using a genetic algorithm; for example, Bayesian optimization can also be used. (1-2) Extraction process (S32) In the extraction step (S32), the crystalline phase closest to the parent material can be extracted using the convex hull created in the convex hull preparation step.

[0019] The crystalline phase closest to the parent material is the first stable crystalline phase that appears when the elements to be substituted in the parent material are replaced with the substitution element. Taking Figure 4 as an example, the crystalline phase closest to parent material A is A6B. Therefore, by using the convex hull created in the convex hull formation process (S31) with the parent material and the substitution element at both ends, the stable crystalline phase closest to the parent material in the convex hull can be extracted and selected. (1-3) Free energy calculation process (S33) In the free energy calculation process (S33), the free energy can be calculated for the parent material and the crystalline phase closest to the parent material when the amount of substitution by the substitution element is changed.

[0020] The method for calculating free energy is not particularly limited. For example, cluster expansion and Monte Carlo simulation can be suitably used, as disclosed in Non-Patent Documents 1 and 2.

[0021] Cluster expansion is a method for calculating the energy of a substance according to the number of "clusters," such as pairs of atoms, triangles, or tetrahedra, contained in its crystal structure.

[0022] Monte Carlo simulation is a method of performing simulations and numerical calculations using random numbers.

[0023] By using cluster expansion, it becomes possible to determine the energy of various crystal structures without performing first-principles calculations, thereby reducing computational complexity and time. In addition, by using Monte Carlo simulation, the statistical mean of the energy of various crystal structures can be efficiently determined, and the free energy can be calculated from the thermodynamic integral of the statistical mean of energy (see Non-Patent Literature 1).

[0024] By using cluster expansion and Monte Carlo simulations, the free energy can be calculated for the parent material and the crystalline phase closest to the parent material when the amount of substitution by the substitution element is varied. The free energy when the amount of substitution by the substitution element is varied in the parent material and the crystalline phase closest to the parent material, by substituting the element to be substituted with the substitution element and changing the amount of substitution.

[0025] In the above explanation, examples were given using cluster expansion and Monte Carlo simulation as methods for calculating the free energy when the amount of substitution by the substitution element is changed for the parent material and the crystalline phase closest to the parent material, but the method is not limited to these forms. For example, molecular dynamics calculations, first-principles molecular dynamics calculations, the CALPHAD method, and the cluster variational method can be used to calculate the above free energy.

[0026] The calculation results of the above changes in free energy are plotted in Figure 5. In Figure 5, the horizontal axis represents the concentration of substitution element B, and the vertical axis represents the free energy. Curve 51 represents the change in free energy when the amount of substitution by substitution element B is changed in the parent material A. Curve 52 represents the change in free energy when the amount of substitution by substitution element B is changed in A6B, which is the crystalline phase closest to the parent material A. (1-4) Calculation process (S34) In the calculation process (S34), the phase boundary can be calculated from the free energy of the parent material and the crystalline phase closest to the parent material, which were calculated in the free energy calculation process (S33), when the amount of substitution by the substitution element is changed.

[0027] For example, in Figure 5, curve 51 shows the change in free energy when the amount of substitution by the substitution element B is changed for the parent material A, which was calculated in the free energy calculation step (S33). Also in Figure 5, curve 52 shows the change in free energy when the amount of substitution by the substitution element B is changed for A6B, the crystalline phase closest to the parent material A, which was calculated in the free energy calculation step (S33).

[0028] Then, the concentration of the substitution element B at the point of tangency 54 between the common tangent line 53, where the slopes of curve 51 and curve 52 are equal, and curve 51, becomes the solid solution limit. Therefore, by drawing the common tangent line 53 between curve 51 and curve 52 and finding the point of tangency 54 with curve 51, the phase boundary point used when calculating the solid solution limit can be calculated.

[0029] The phase boundary calculation process (S21) can be repeated by changing conditions such as temperature. For example, by repeatedly performing the process with a changed temperature, the change in the phase boundary due to temperature changes can be calculated. (2) Solid solution limit calculation process (S22) The solid solution limit calculation step (S22) calculates the solid solution limit of the substitution element in the parent material from the phase boundary obtained in the phase boundary calculation step (S21).

[0030] Specifically, for example, the concentration of substitution element B at the phase boundary obtained in the phase boundary calculation step (S21) can be output as the solid solution limit. That is, in the example shown in Figure 5, the concentration of substitution element B at point 55 can be output as the solid solution limit. Furthermore, if the phase boundary calculation is repeated in the phase boundary calculation step (S21) by changing conditions such as temperature, it is also possible to output a phase diagram showing the change in the solid solution limit due to changes in temperature, etc.

[0031] The solid solution limit calculation method of this embodiment may include any steps other than the phase boundary calculation step and the solid solution limit calculation step described above. The optional steps will be described below. (3) Any process (3-1) Reception Process In the reception process, information on the target parent material and substitution elements can be received and acquired, and can be performed, for example, before the phase boundary calculation process (S21). In the reception process, information on the crystal structure of the parent material, the elements substituted by the substitution elements in the parent material, and information about the substitution elements can be acquired. For example, the crystal structure can be in Crystallographic Information File (CIF) format. The substitution elements are not particularly limited and can be any elements present in the periodic table. (3-2) Judgment process For example, if the solid solubility limit has been calculated in the past using the solid solubility limit calculation method of this embodiment, or if the phase diagram is already known, then new calculations may not be necessary.

[0032] Therefore, the solid solution limit calculation method of this embodiment may also include a step for calculating the solid solution limit when substituting the parent substance and the element to be substituted in the parent substance with the substitution element, and a step for determining whether the phase diagram has already been calculated.

[0033] Specifically, for example, information about the parent material and substitution elements used in the phase boundary calculation process (S21) can be compared with a phase diagram database to make a determination. Furthermore, if necessary, the determination can also be made by comparing it with past calculation results. Additionally, as described in the data presentation process, the conditions for the parent material and substitution elements previously specified by the user can be stored in the phase diagram database, and similar calculation results can be presented by comparing them with the information about the parent material and substitution elements used in the phase boundary calculation process. Therefore, the determination process can be performed before the phase boundary calculation process (S21), or, for example, after the reception process.

[0034] A phase diagram database is a record of phase diagrams with various substances at both ends. Phase diagrams are created from the temperature-concentration dependence of the boundaries between crystalline phases, as reported in previous experimental and computational studies. If the target phase diagram exists in the phase diagram database, the solid solution limit calculation process can be performed using that phase diagram. If the phase diagram does not exist, the process can proceed to the phase boundary calculation process (S21). (3-3) Storage process, data presentation process When calculating and creating solid solubility limits or phase diagrams using the solid solubility limit calculation method of this embodiment or by other methods, it is preferable to save the calculation results. Furthermore, in order to determine whether the solid solubility limit values ​​calculated in the solid solubility limit calculation step described above are appropriate, it is preferable that the saved solid solubility limit and phase diagram data are presented for the parent substance and substitution elements used in the solid solubility limit calculation step under similar conditions.

[0035] Therefore, the method for calculating the solid solution limit in this embodiment preferably includes the following storage step and data presentation step.

[0036] The storage process allows for the storage of previously calculated solid solubility limits or previously created phase diagrams.

[0037] The data presentation step can present similar data from among the solid solubility limits or phase diagrams stored in the storage step, based on user-specified conditions that include at least substitutional elements.

[0038] In the storage step, data on solid solubility limits and phase diagrams measured and calculated using the solid solubility limit calculation method of this embodiment, or by other methods such as experiments, can be stored. In the storage step, data from a known phase diagram database may also be imported and stored. The data stored in the storage step can also be used in the judgment step described above.

[0039] The timing of the preservation process is not particularly limited; for example, it can be performed before the solid solubility limit calculation process described above.

[0040] In the data presentation process, data similar to the solid solubility limit and phase diagram data stored in the storage process can be presented, for example, for the parent substance and substitution elements entered by the user in the aforementioned reception process.

[0041] In the data presentation process, specifically, for example, data such as solid solubility limit data and phase diagram data stored in the storage process can be selected and presented if the substitution element used is an element with similar properties to the user-inputted substitution element, such as being in the same group or located in a nearby position in the periodic table. Furthermore, in the data presentation process, data such as solid solubility limit data and phase diagram data stored in the storage process can be selected and presented if the substitution element is the same and the parent material has the same or similar crystal structure. The range for determining similarity can be predetermined and is not particularly limited.

[0042] In the data presentation step, similar data is presented based on user-specified conditions, including at least substitution elements. By comparing this data with the solid solubility limit value calculated in the previously described solid solubility limit calculation step, it is possible to examine and determine whether the solid solubility limit value is appropriate.

[0043] The timing of the data presentation process is not particularly limited and can be performed at any time after the reception process. For example, the data presentation process may be performed before the phase boundary calculation process, or it may be performed at the same time as outputting the solid solution limits calculated after the solid solution limit calculation process.

[0044] According to the solid solution limit calculation method of this embodiment described above, the solid solution limit of a substitution element in the parent material can be calculated even when the phase diagram is unknown. [Solid Solution Limit Calculation Device] The solid solution limit calculation device of this embodiment will now be described. According to the solid solution limit calculation device of this embodiment, the previously described solid solution limit calculation method can be implemented. Therefore, some of the previously explained matters will be omitted.

[0045] The solid solution limit calculation device of this embodiment may have the following phase boundary calculation unit and solid solution limit calculation unit.

[0046] As shown in the hardware configuration diagram in Figure 6, the solid solution limit calculation device 60 of this embodiment is composed of, for example, an information processing device (computer). Physically, the solid solution limit calculation device 60 can be configured as a computer system including a processor 61 which is the calculation processing unit, a memory 62 which is the main memory, an auxiliary storage device 63, an input / output interface 64, an input device 65, an output device 66, etc. These are interconnected by a bus 67. Note that the auxiliary storage device 63, the input device 65, and the output device 66 may be provided externally.

[0047] The processor 61 can consist of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and controls the overall operation of the solid solution limit calculation device 60 and performs various information processing. The processor 61 can calculate the solid solution limit, etc., by executing, for example, the solid solution limit calculation method described above or a program (simulation program) stored in the memory 62 or auxiliary storage device 63.

[0048] Memory 62 is used as a work area for the processor 61 and can store key control parameters and information.

[0049] Memory 62 can store programs (simulation programs), etc.

[0050] The auxiliary storage device 63 is a storage device such as an SSD (Solid State Drive) or an HDD (Hard Disk Drive), and can store various data, files, etc. necessary for the operation of the substitution element search device.

[0051] The input / output interface 64 includes a communication interface that takes in information from an external data acquisition server, etc., and outputs the analyzed information to other electronic devices.

[0052] The input device 65 is a user interface such as a touch panel, keyboard, display screen, or operation buttons.

[0053] The output device 66 is a monitor display or the like. The output device 66 displays an analysis screen, and the screen is updated in response to input operations via the input device 65 or the like.

[0054] Each function of the solid solution limit calculation device 60 shown in Figure 6 can be realized by, for example, reading a program (simulation program) from the main memory such as memory 62 or the auxiliary memory 63, executing it with the processor 61, thereby reading and writing data to memory 62, etc., and operating the input / output interface 64 and the output device 66.

[0055] Figure 7 shows a functional block diagram of the solid solution limit calculation device 60 of this embodiment.

[0056] Each part of the solid solution limit calculation device 60 shown in Figure 7 is realized through the collaborative action of software and hardware by executing, for example, the solid solution limit calculation method described above or a program pre-stored in the processor of an information processing device such as a personal computer equipped with a processor, memory, and various interfaces of the solid solution limit calculation device 60.

[0057] The composition of each part is described below. (A) Reception Department The reception unit 71 receives commands and data input from the user related to the processing performed by the processing unit 72. Examples of the reception unit 71 include a keyboard or mouse operated by the user to input commands, a communication device that receives input via a network, and a reading device that receives input from various storage media such as CD-ROMs and DVD-ROMs. (B) Processing apparatus As shown in Figure 7, the processing apparatus 72 may have a phase boundary calculation unit 721 and a solid solution limit calculation unit 722. (B-1) Phase boundary calculation part The phase boundary calculation unit 721 calculates the phase boundary between the parent material and the crystalline phase closest to the parent material when the parent material and the substituted element are represented as a phase diagram, based on information about the parent material and the substituted element.

[0058] The phase boundary calculation unit 721 may include, for example, a convex hull creation unit 81, an extraction unit 82, a free energy calculation unit 83, and a calculation unit 84, as shown in Figure 8.

[0059] The following describes each part. (Convex hull creation section) The convex hull creation unit 81 can create a convex hull with the parent substance and the substituted element at both ends by first-principles calculations using a genetic algorithm.

[0060] (Extraction part) The extraction unit 82 can extract the crystalline phase closest to the parent material using a convex hull.

[0061] (Free energy calculation unit) The free energy calculation unit 83 can calculate the free energy of the parent material and the crystalline phase closest to the parent material when the amount of substitution by the substitution element is changed.

[0062] (Calculation section) The calculation unit 84 can calculate the phase boundary from the free energy of the parent material and the crystalline phase closest to the parent material, calculated by the free energy calculation unit 83, when the amount of substitution by the substitution element is changed.

[0063] Since the terminology and operating procedures for each part have already been explained in the section on the solid solution limit calculation method, we will omit further explanation here. (B-2) Solid solubility limit calculation section The solid solution limit calculation unit 722 calculates the solid solution limit of the substitution element in the parent material from the phase boundary obtained by the phase boundary calculation unit 721.

[0064] The method for calculating the solid solubility limit has already been explained, so the explanation will be omitted here. (C) Output section The output unit 73 may have a display or the like. The results obtained by the solid solution limit calculation unit 722 can be output to the output unit 73.

[0065] Specifically, for example, the concentration of the substitution element calculated by the solid solution limit calculation unit 722 from the phase boundary obtained by the phase boundary calculation unit 721 can be output as the solid solution limit. Furthermore, if the phase boundary calculation unit 721 repeatedly performs phase boundary calculations by changing conditions such as temperature, it can also output a phase diagram showing the change in the solid solution limit due to changes in temperature, etc. (D) Judgment section The solid solution limit calculation device of this embodiment may also have a determination unit if necessary.

[0066] The determination unit can determine whether the solid solubility limits for substituting the parent material and the elements to be substituted in the parent material with the substitution elements, as well as whether the phase diagram has already been calculated.

[0067] The determination method has already been explained in the section on calculating the solid solubility limit, so the explanation will be omitted here. (E) Storage section, data presentation section The solid solution limit calculation device of this embodiment may also have a storage unit and a data display unit as needed.

[0068] The storage section can save previously calculated solid solubility limits or previously created phase diagrams.

[0069] The data presentation unit can present similar data from among the solid solubility limits or phase diagrams stored in the storage unit, based on user-specified conditions that include at least a substitution element.

[0070] The storage unit and the data presentation unit can perform the storage process and data presentation process described in the previously stated method for calculating the solid solubility limit, respectively, and since this has already been explained, the explanation will be omitted.

[0071] According to the solid solution limit calculation device of this embodiment described above, the solid solution limit of a substitution element in the parent material can be calculated even when the phase diagram is unknown. [Solid Solution Limit Calculation System] The solid solution limit calculation system of this embodiment will now be described. According to the solid solution limit calculation system of this embodiment, the previously described solid solution limit calculation method can be implemented. Therefore, some of the previously explained matters will be omitted.

[0072] The solid solution limit calculation system may include a phase boundary calculation unit and a solid solution limit calculation unit.

[0073] The phase boundary calculation unit and the solid solution limit calculation unit can be configured in the same way as the solid solution limit calculation device described above.

[0074] In other words, the phase boundary calculation unit calculates the phase boundary between the parent material and the crystalline phase closest to the parent material when the parent material and the substituted element are represented as a phase diagram, based on information about the parent material and the substituted element.

[0075] The solid solution limit calculation unit calculates the solid solution limit of the substitution element in the parent material from the phase boundary obtained by the phase boundary calculation unit.

[0076] Furthermore, the phase boundary calculation unit may include, for example, a convex hull creation unit, an extraction unit, a free energy calculation unit, and a calculation unit.

[0077] The convex hull generation unit can create a convex hull with the parent substance and the substituted element at both ends by first-principles calculations using a genetic algorithm.

[0078] The extraction unit uses a convex hull to extract the crystalline phase closest to the parent material.

[0079] The free energy calculation unit can calculate the free energy of the parent material and the crystalline phase closest to the parent material when the amount of substitution by the substitution element is changed.

[0080] The calculation unit can calculate the phase boundary from the free energy of the parent material and the crystalline phase closest to the parent material, calculated by the free energy calculation unit, when the amount of substitution by the substitution element is changed.

[0081] The solid solution limit calculation system of this embodiment may also include, if necessary, a determination unit, a storage unit, a data presentation unit, etc., as described in the section on solid solution limit calculation devices, etc.

[0082] Since terminology and operating procedures for each part have already been explained in the sections on the solid solution limit calculation method and the solid solution limit calculation apparatus, we will omit further explanation here.

[0083] As shown in Figure 9, the solid solution limit calculation system 90 of this embodiment can include a plurality of processing devices, such as a first processing device 91 and a second processing device 92, and each processing device can be configured to exchange data via a network 93.

[0084] The first processing unit 91 and the second processing unit 92 can be, for example, information processing devices (computers). The first processing unit 91 and the second processing unit 92 may be portable or stationary terminals, or they may be server devices.

[0085] The type of network 93 is not particularly limited; it can be any network that allows data to be exchanged between the first processing unit 91 and the second processing unit 92, and can be wireless or wired.

[0086] In the solid solution limit calculation system 90 of this embodiment, for example, the first processing unit 91 can function as part of the phase boundary calculation unit and solid solution limit calculation unit described above, and the remaining part can be performed by the second processing unit 92. Furthermore, the processing units of the solid solution limit calculation system 90 of this embodiment are not limited to the first processing unit 91 and the second processing unit 92, but can also be divided among multiple processing units.

[0087] According to the solid solution limit calculation system of this embodiment described above, the solid solution limit of a substitution element in the parent material can be calculated even when the phase diagram is unknown. [program] Next, the program of this embodiment will be described.

[0088] The program of this embodiment allows the computer to function as the following phase boundary calculation unit and solid solution limit calculation unit.

[0089] The phase boundary calculation unit calculates the phase boundary between the parent material and the crystalline phase closest to the parent material, based on information about the target parent material and the substitution element.

[0090] The solid solution limit calculation unit calculates the solid solution limit of the substitution element in the parent material from the phase boundary obtained by the phase boundary calculation unit.

[0091] Furthermore, the phase boundary calculation unit may include, for example, a convex hull creation unit, an extraction unit, a free energy calculation unit, and a calculation unit.

[0092] The convex hull generation unit can create a convex hull with the parent substance and the substituted element at both ends by first-principles calculations using a genetic algorithm.

[0093] The extraction unit uses a convex hull to extract the crystalline phase closest to the parent material.

[0094] The free energy calculation unit can calculate the free energy of the parent material and the crystalline phase closest to the parent material when the amount of substitution by the substitution element is changed.

[0095] The calculation unit can calculate the phase boundary from the free energy of the parent material and the crystalline phase closest to the parent material, calculated by the free energy calculation unit, when the amount of substitution by the substitution element is changed.

[0096] The program of this embodiment can, if necessary, also allow the computer to function as a determination unit, storage unit, or data presentation unit as described in the section on solid solution limit calculation device, etc.

[0097] The program of this embodiment can be stored in various storage media of the main memory or auxiliary storage device, such as the memory of the solid solution limit calculation device described above. By loading this program and executing it with a processor, data can be read and written to the memory, and the input / output interface and display device can be operated. Therefore, explanations of the solid solution limit calculation method and the solid solution limit calculation device, etc., which have already been described, will be omitted.

[0098] The program of this embodiment described above may be stored on a computer connected to a network such as the Internet and provided by allowing users to download it via the network. Alternatively, the program of this embodiment may be configured to be provided and distributed via a network such as the Internet.

[0099] The program of this embodiment may be distributed or otherwise provided in a state where it is stored on an optical disc such as a CD-ROM or on a recording medium such as a semiconductor memory.

[0100] According to the program of this embodiment described above, the solid solubility limit of the substitution element in the parent material can be calculated even when the phase diagram is unknown. [Explanation of Symbols]

[0101] 10. Phase Diagram 20 Flowcharts S21 Phase boundary calculation process S22 Solid Solution Limit Calculation Process 30 Flowcharts S31 Convex Hull Creation Process S32 Extraction process S33 Free energy calculation process S34 Calculation process 41 lines 51, 52 curve 53 Common tangent 54 contacts 55 points 60. Solid Solution Limit Calculation Device 61 processors 62 memory 63 Auxiliary storage device 64 input / output interfaces 65 Input device 66 Output device 71 Reception Department 72 Processing Unit 721 Phase boundary calculation part 722 Solid Solution Limit Calculation Unit 73 Output section 81 Convex Hull Creation Section 82 Extraction part 83 Free Energy Calculation Unit 84 Calculation Unit 90 Solid Solution Limit Calculation System 91 First Processing Unit 92 Second Processing Unit 93 Network

Claims

1. A phase boundary calculation step calculates the phase boundary between the target parent material and the crystalline phase closest to the parent material when the parent material and the substituted element are represented as a phase diagram, based on information about the target parent material and the substituted element. The process includes a solid solution limit calculation step, which calculates the solid solution limit of the substitution element in the parent material from the phase boundary obtained in the phase boundary calculation step, The aforementioned phase boundary calculation step is: A convex hull creation step, in which a convex hull is created with the parent substance and the substituted element as its ends by first-principles calculation using a genetic algorithm, An extraction step in which the crystalline phase closest to the parent material is extracted using the aforementioned convex hull, A free energy calculation step for the parent material and the crystalline phase closest to the parent material, in which the free energy is calculated when the amount of substitution by the substitution element is changed, A method for calculating a solid solution limit, comprising: a calculation step of calculating the phase boundary from the free energy when the amount of substitution by the substitution element is changed for the parent material and the crystalline phase closest to the parent material, which were calculated in the free energy calculation step.

2. A phase boundary calculation unit calculates the phase boundary between the target parent material and the crystalline phase closest to the parent material when the parent material and the substituted element are represented as a phase diagram, based on information about the target parent material and the substituted element. The system includes a solid solution limit calculation unit that calculates the solid solution limit of the substitution element in the parent material from the phase boundary obtained by the phase boundary calculation unit, The phase boundary calculation unit, A convex hull creation unit that creates a convex hull with the parent substance and the substituted element at both ends by first-principles calculations using a genetic algorithm, An extraction unit that uses the aforementioned convex hull to extract the crystalline phase closest to the parent material, A free energy calculation unit that calculates the free energy when the amount of substitution by the substitution element is changed for the parent material and the crystalline phase closest to the parent material, A solid solution limit calculation apparatus, comprising: a calculation unit that calculates the phase boundary from the free energy when the amount of substitution by the substitution element is changed for the parent material and the crystalline phase closest to the parent material, which are calculated by the free energy calculation unit, the amount of substitution by the substitution element is changed; and a solid solution limit calculation apparatus, comprising: a calculation unit that calculates the phase boundary from the free energy when the amount of substitution by the substitution element is changed for the parent material and the crystalline phase closest to the parent material, which are calculated by the free energy calculation unit

3. A storage unit that stores previously calculated solid solubility limits or previously created phase diagrams, The solid solution limit calculation apparatus according to claim 2, further comprising: a data presentation unit that presents similar data from among solid solution limits or phase diagrams stored in the storage unit, based on user-specified conditions, including at least the substitution element.

4. A phase boundary calculation unit calculates the phase boundary between the target parent material and the crystalline phase closest to the parent material when the parent material and the substituted element are represented as a phase diagram, based on information about the target parent material and the substituted element. The system includes a solid solution limit calculation unit that calculates the solid solution limit of the substitution element in the parent material from the phase boundary obtained by the phase boundary calculation unit, The phase boundary calculation unit, A convex hull creation unit that creates a convex hull with the parent substance and the substituted element at both ends by first-principles calculations using a genetic algorithm, An extraction unit that uses the aforementioned convex hull to extract the crystalline phase closest to the parent material, A free energy calculation unit that calculates the free energy when the amount of substitution by the substitution element is changed for the parent material and the crystalline phase closest to the parent material, A solid solution limit calculation system including a calculation unit that calculates the phase boundary from the free energy when the amount of substitution by the substitution element is changed for the parent material and the crystalline phase closest to the parent material, which are calculated by the free energy calculation unit, the amount of substitution by the substitution element is changed.

5. Computers, A phase boundary calculation unit calculates the phase boundary between the target parent material and the crystalline phase closest to the parent material when the parent material and the substituted element are represented as a phase diagram, based on information about the target parent material and the substituted element. The phase boundary obtained by the phase boundary calculation unit is used to calculate the solid solution limit of the substitution element in the parent material, and this unit functions as a solid solution limit calculation unit. The phase boundary calculation unit, A convex hull creation unit that creates a convex hull with the parent substance and the substituted element at both ends by first-principles calculations using a genetic algorithm, An extraction unit that uses the aforementioned convex hull to extract the crystalline phase closest to the parent material, A free energy calculation unit that calculates the free energy when the amount of substitution by the substitution element is changed for the parent material and the crystalline phase closest to the parent material, A program including a calculation unit that calculates the phase boundary from the free energy of the parent material and the crystalline phase closest to the parent material, calculated by the free energy calculation unit, when the amount of substitution by the substitution element is changed.

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