Dissimilar metal connection transition layer gradient path design method based on thermodynamic calculation

Abstract

The invention relates to a dissimilar metal connection multi-component transition layer gradient path design method based on thermodynamic calculation. The method comprises the steps that an alloy component combination is constructed; performing high-flux iteration on a solidification path under all component combinations through thermodynamic calculation to obtain the phase composition of the component combinations of the transition layer at the melting point along with the gradient change of the components of the base metal; a multi-component transition layer component area with high solid solubility for a base material is determined by constructing a quaternary feasibility prediction map of a transition layer alloy under the gradient content of the base material; and on the basis of the selected target transition layer alloy components, a feasibility prediction map and a phase distribution map between the base material and the target transition layer alloy are constructed, and gradient path design between the base material and the target transition layer alloy is achieved. According to the method, by introducing the feasibility prediction map of the quaternary system, the component design space of the transition layer is remarkably widened, and the screening efficiency of the transition layer alloy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of alloy composition design. BACKGROUND

[0002] Dissimilar metals are widely used in aerospace, marine engineering and energy equipment fields by integrating the excellent properties of different materials into the same component. However, the thermal physical properties of the base materials differ greatly and brittle phases are easily formed during the connection process, and even cracks are induced, thereby seriously damaging the service performance of the component. In order to alleviate the mismatch of structure and performance caused by the abrupt interface during the connection process, a gradient path strategy is introduced into the design of dissimilar metal connection, which builds a multi-stage or continuous composition, structure and thermal property gradient transition layer between the base materials, so that the thermal stress is released step by step and the formation of brittle intermetallic compounds is inhibited. Therefore, reasonable gradient path design is of great significance to improve the performance of dissimilar metal connection.

[0003] The document “L. D. Bobbio, B. Bocklund, E. Simsek, R. T. Ott, M. J. Kramer, Z. K. Liu, A. M. Beese, Design of an additively manufactured functionally graded material of 316 stainless steel and Ti-6Al-4V with Ni-20Cr, Cr, and V intermediate compositions, Additive Manufacturing, 2022, 51: 102649.” discloses a method for designing a gradient path for titanium / steel dissimilar metal connection based on thermodynamic calculation. The method uses Scheil-Gulliver model and Lever Rule model to build the feasibility prediction diagram of different ternary systems in Cr-Fe-Ni-Ti-V, aiming to avoid the formation of brittle intermetallic compounds when connecting titanium alloy and steel, and respectively selects elements that do not form intermetallic compounds with Fe and Ti, designs the gradient path of Fe-Ni20Cr-Cr-V-Ti, and realizes the preparation of functional gradient material without harmful intermetallic compounds. The gradient path design method considers two extreme cases in the solidification process, can accurately predict the phase change behavior, and effectively avoids the formation of harmful intermetallic compounds in the gradient path.

[0004] However, the feasibility prediction diagram built by this method is based on ternary systems, only realizes the visualization of three components, and the degree of freedom of components is limited, so that the designed transition layer is often limited to a single or a few component systems, making it difficult to meet the design requirements of complex composition in the multi-component transition layer in dissimilar metal connection. SUMMARY

[0005] The present application aims to avoid the deficiencies of the prior art to provide a Scheil-Gulliver model and Lever Rule model based on the goal of reducing the content of intermetallic compounds, respectively constructing the quaternary feasibility prediction map of alloy composition combination under the gradient content of base material and transition layer alloy, determining the multi-component transition layer composition region with high solid solubility to the base material, and realizing the heterogeneous metal connection transition layer gradient path design method based on thermodynamic calculation.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows: a heterogeneous metal connection transition layer gradient path design method based on thermodynamic calculation, comprising the following steps: Step one, taking the independently controllable component units in the transition layer alloy as components, and setting the step length of different components to ensure that the sum of different components is 100 at.%, the alloy composition combination under the gradient content of base material and transition layer composition is generated for thermodynamic calculation; Step two, combining thermodynamic calculation, Scheil-Gulliver model and Lever Rule model are used for high-throughput iterative calculation of alloy composition combination, wherein Scheil-Gulliver model and Lever Rule model are used to describe the distribution law of solute elements under non-equilibrium and equilibrium solidification conditions; Thus, the solidification path of the alloy composition combination is obtained, as well as the phase type and phase content data of all alloy composition combinations at the melting point , and the mole fraction of solid solution and the mole fraction of intermetallic compounds under different models are counted. Step three, according to the actual connection design requirements, the threshold value of intermetallic compound content is given , and the mole fraction under the conditions of two models, then the corresponding alloy composition combination is considered feasible, otherwise it is not feasible; Further, according to the relationship between the threshold value and the mole fraction , the alloy composition combination is divided into feasible and infeasible regions, and the composition combination of the transition layer alloy is normalized, the feasibility prediction map of the alloy composition combination is constructed, and the composition combination region of the feasible transition layer alloy with high solid solubility to the heterogeneous metal base material is screened. Step four, according to the obtained feasible transition layer composition combination area, the target transition layer alloy composition is selected, and then the dissimilar metal base material and the target transition layer alloy are used as components, and the feasibility prediction diagram and the phase distribution diagram of the dissimilar alloy connection are calculated, that is, the gradient path design of the dissimilar alloy connection is realized.

[0007] Further, in step two, the Scheil-Gulliver model is suitable for predicting non-equilibrium phases formed under rapid cooling conditions. The Scheil-Gulliver model is based on the assumptions of solid-phase non-diffusion, liquid-phase uniform composition, and local equilibrium of solid-liquid interface. The basic equation of the Scheil-Gulliver model is: , , , In the formula, is the solid phase fraction, is the initial composition of the component, is the liquid phase composition, is the solid phase composition, is the solubility distribution coefficient. That is, the classical Scheil-Gulliver equation is obtained: , .

[0008] Further, the Lever Rule model is suitable for predicting equilibrium phases formed in slow cooling process. The basic equation of the Lever Rule model is: , , That is, the equation of the Lever Rule model is obtained: , , In the formula, is the solid phase fraction, is the initial composition of the component, is the liquid phase composition, is the solid phase composition, is the solubility distribution coefficient.

[0009] Further, the specific steps of the high-throughput iterative calculation in step two are: Scheil-Gulliver model and Lever Rule model are used to iteratively calculate the solidification path of all alloy composition combinations, and the solid phase mole fraction To screen the conditions, i.e. obtain all alloy composition combinations at the melting point The results of the phase type and phase content.

[0010] Further, the high-throughput iterative calculation is performed by using the high-entropy alloy database panHEA and the High Throughtput Calculation module in the Pandat software.

[0011] Further, step three is specifically, according to the relationship between the threshold value and the mole fraction , the composition combinations of the transition layer under different matrix gradient contents are divided into four regions: Scheil-Gulliver model and Lever Rule model are feasible region; Scheil-Gulliver model is feasible, and Lever Rule model is not feasible region; Scheil-Gulliver model is not feasible, and Lever Rule model is feasible region; Scheil-Gulliver model and Lever Rule model are not feasible region; Then, the composition combinations of the transition layer alloy are normalized, and the feasibility prediction map of the alloy composition combinations under the gradient content change of the dissimilar metal matrix and the transition layer composition is constructed respectively; Further, the intersection of the feasible region in the feasibility prediction map is selected, i.e. the feasible transition layer composition region with high solid solubility for the dissimilar metal matrix is obtained.

[0012] Further, in step three, the independently controllable composition units in the dissimilar metal matrix and the transition layer alloy are respectively taken as the group elements, according to the relationship between the threshold value and the mole fraction , the alloy composition is divided into feasible and infeasible regions, and the four-element feasibility prediction map of the alloy composition under the gradient content of the dissimilar metal matrix and the transition layer alloy is constructed.

[0013] Further, the calculation of the feasibility prediction map of the dissimilar alloy connection in step four is to take the dissimilar metal matrix and the target transition layer alloy as the group elements, and then obtain the feasibility prediction map according to the calculation method of steps one to three.

[0014] Further, the dissimilar metal matrix is titanium alloy and steel or titanium alloy and aluminum alloy or steel and aluminum alloy, and the elements of the transition layer alloy include Cr, Cu, V, Ni or Cu, Sn, Ag or Zn, Cu, Ni.

[0015] The beneficial effects of this invention are as follows: Based on thermodynamic calculations, a quaternary feasibility prediction diagram of alloy composition combinations under gradient content of the base material and the transition layer alloy is constructed, and the transition layer composition region with high solid solubility with the base material is determined. At the same time, based on the selected target transition layer composition, a feasibility prediction diagram and phase distribution diagram between the base material and the target transition layer alloy are established, realizing the gradient path design between the base material and the target transition layer alloy.

[0016] Furthermore, by introducing a feasibility prediction diagram for a quaternary system, this method increases the visualization dimension of the components, significantly broadens the design space of the transition layer components, and provides theoretical guidance for the gradient path design of multi-component transition layers connecting dissimilar metals. Attached Figure Description

[0017] Figure 1 This is a flowchart of a gradient path design method for a dissimilar metal connection transition layer based on thermodynamic calculations, as described in this invention. Figure 2 The alloy composition combination of the Fe and CrCuV transition layer alloy under the gradient content of the present invention has a melting point Feasibility prediction diagram for the location; Among them (a) Fe=10 at.%; (b) Fe=30 at.%; (c) Fe=50 at.%; (d) Fe=70 at.%; (e) Fe=90 at.%; Figure 3 The alloy composition combination of the Ti and CrCuV transition layer alloy with gradient content in this invention has a melting point. Feasibility prediction diagram for the location; Among them, (a) Ti=10 at.%; (b) Ti=30 at.%; (c) Ti=50 at.%; (d) Ti=70 at.%; (e) Ti=90 at.% Figure 4 This invention relates to the compositional combination of the CrCuV transition layer with high solid solubility for Fe and Ti, and the target transition layer alloy composition. Figure 5 The Fe-Cr of the present invention 0.8 Cu 0.1 V 1.2 -Ti feasibility prediction diagram and gradient path; Figure 6 The present invention is (a)Fe-Cr 0.8 Cu 0.1 V 1.2 and Cr 0.8 Cu 0.1 V 1.2 -Ti pseudo-binary phase diagram; Fe-Cr 0.8 Cu 0.1 V 1.2Phase distribution prediction map of Ti: (b) Scheil-Gulliver model; (c) Lever Rule model. DETAILED DESCRIPTION

[0018] The principles and features of the present application are described below in conjunction with the accompanying drawings, which are provided only for explanation of the present application and are not intended to limit the scope of the present application.

[0019] To achieve the above-mentioned purpose, the present application provides the following detailed implementation: Example 1: A heterogeneous metal connection transition layer gradient path design method based on thermodynamic calculation, comprising the following steps: Step one, taking the heterogeneous metal base material and the independently controllable component unit in the transition layer alloy as the group element, setting the step length for different group elements to ensure that the sum of different group elements is 100 at.%, generating alloy component combinations under the component gradient content change of the base material and the transition layer, for thermodynamic calculation; Step two, combining thermodynamic calculation, respectively using Scheil-Gulliver model and Lever Rule model to perform high-throughput iterative calculation on the alloy component combination, wherein the Scheil-Gulliver model and the Lever Rule model are respectively used to describe the distribution law of solute elements under non-equilibrium and equilibrium solidification conditions; Among them, the Scheil-Gulliver model is suitable for predicting non-equilibrium phases formed under rapid cooling conditions, the Scheil-Gulliver model is based on the assumptions of no diffusion in solid phase, uniform composition in liquid phase, and local equilibrium at solid-liquid interface, and the basic equation of the Scheil-Gulliver model is: , , , In the formula, is the solid phase fraction, is the initial composition of the group element, is the liquid phase composition, is the solid phase composition, is the solute distribution coefficient; That is, the classical Scheil-Gulliver equation can be obtained: , .

[0020] Among them, the Lever Rule model is suitable for predicting equilibrium phases formed in the slow cooling process, and the basic equation of the Lever Rule model is: , , That is, the equation of Lever Rule model is obtained as follows: , , In the formula, is the solid phase fraction, is the initial composition of the component, is the liquid phase composition, is the solid phase composition, is the solute distribution coefficient.

[0021] Further, the high-throughput iterative calculation is performed by using the high-entropy alloy database panHEA in the Pandat software and the HighThroughtput Calculation module, and the specific steps are as follows: The Scheil-Gulliver model and the Lever Rule model are used respectively to iteratively calculate the solidification paths of all alloy composition combinations, and the solid phase mole fraction is set as the screening condition, that is, the phase types and phase contents of all alloy composition combinations at the melting point are obtained.

[0022] Based on the obtained solidification paths of the alloy composition combinations and the phase types and phase contents of all alloy composition combinations at the melting point , the mole fraction of the solid solution and the mole fraction of the intermetallic compound under different models are counted.

[0023] Step three, according to the actual connection design requirement, the threshold value of the intermetallic compound content is given , and the mole fraction under the two models is considered to be feasible, otherwise it is not feasible; that is, according to the relationship between the and the , the transition layer composition under different base material gradient contents is divided into four regions: the region where both the Scheil-Gulliver model and the Lever Rule model are feasible; the region where the Scheil-Gulliver model is feasible and the Lever Rule model is not feasible; the region where the Scheil-Gulliver model is not feasible and the Lever Rule model is feasible; Scheil-Gulliver model and Lever Rule model are not feasible region; Next, the composition combination of the transition layer alloy is normalized, and the feasibility prediction map of the alloy composition combination under the composition gradient content change of the dissimilar metal base material and the transition layer is constructed respectively; Further, the composition combination region of the feasibility transition layer alloy with high solid solubility to the base material A and the base material B is screened, that is, the intersection of the feasible region in the feasibility prediction map is selected, so that the composition combination region of the feasibility transition layer with high solid solubility to the base material A and the base material B is obtained.

[0024] Step four, according to the obtained feasibility transition layer composition combination region, the target transition layer alloy composition is selected, and then the dissimilar alloy connection feasibility prediction map and phase distribution map are calculated by taking the dissimilar metal base material and the target transition layer alloy as components, that is, the gradient path design of dissimilar alloy connection is realized. Among them, the calculation of the feasibility prediction map of dissimilar alloy connection is to take the dissimilar metal base material and the target transition layer alloy as components, and then obtain the feasibility prediction map according to the calculation method of steps one to three.

[0025] Example 2: the same as example 1, except that the thermodynamic calculation-based dissimilar metal connection transition layer gradient path design method includes the following steps: Step one, taking titanium alloy and steel as the research object, CrCuV duplex alloy with thermal physical properties between titanium alloy and steel as the transition layer, and the alloy composition is expressed by atomic percentage, according to the element composition range and step length in table 1 and table 2, 2255 kinds of FeCrCuV and 2255 kinds of TiCrCuV alloy composition are calculated by Python program, which provides input data set for subsequent thermodynamic calculation; Among them, table 1 is the component composition range and calculation step length table of FeCrCuV, and table 2 is the component composition range and calculation step length table of TiCrCuV, Table 1

[0026] Table 2

[0027] Step two, using Pandat software high entropy alloy database (panHEA) and High ThroughtputCalculation module, respectively adopting Scheil-Gulliver model and Lever Rule model, high-throughput iterative calculation of the solidification path of the alloy composition under the gradient content change of different Fe, Ti and transition layer alloy obtained in step one; Set the condition solid mole fraction , export excel result file containing all the component combinations in the melting point phase type, phase content, respectively, statistics of different models of the mole fraction of solid solution and intermetallic compounds ; Step three, screening Fe element high solid solubility of CrCuV transition layer alloy composition. Set the intermetallic compound content threshold 10 at.% in FeCrCuV alloy composition combination, under the condition of Fe content is 10 at.%, 30 at.%, 50 at.%, 70 at.%, 90 at.%, according to the calculated phase composition results, if the intermetallic compound content in FeCrCuV alloy composition combination is , then the alloy composition combination is feasible; According to the relationship between and , FeCrCuV alloy composition combination can be divided into four regions: Scheil and Lever are feasible, Scheil is feasible and Lever is not feasible, Scheil is not feasible and Lever is feasible, and Scheil and Lever are not feasible; Further, screening Ti element high solid solubility of CrCuV transition layer alloy composition. Set the intermetallic compound content threshold 30 at.% in TiCrCuV alloy composition combination, under the condition of Ti content is 10 at.%, 30 at.%, 50 at.%, 70 at.%, 90 at.%, according to the calculated phase composition results, if the intermetallic compound content in TiCrCuV alloy composition combination is , then it is feasible. According to the relationship between and , TiCrCuV alloy composition combination can be divided into four regions: Scheil and Lever are feasible, Scheil is feasible and Lever is not feasible, Scheil is not feasible and Lever is feasible, and Scheil and Lever are not feasible; The normalized treatment of CrCuV alloy composition under different Fe and Ti gradient content is carried out, and the increase of one component degree of freedom is realized by introducing the change of matrix gradient content, and the quaternary feasibility prediction diagram of alloy composition combination at melting point of Fe and CrCuV alloy gradient content and the quaternary feasibility prediction diagram of alloy composition combination at melting point of Ti and CrCuV alloy gradient content.

[0028] The intersection of the regions where both Fe gradient and Ti gradient CrCuV alloy composition combinations are feasible is selected, that is, the region where CrCuV alloy composition combinations with high solid solubility for both Fe and Ti are obtained, mainly concentrated in the V-rich region where Cr:V is less than 2:3. Step 4: Based on the feasible composition combination region boundary Cr:V ratio of 2:3, and the design concept of FCC+BCC dual-phase synergistic strengthening transition layer alloy, the Cu content is changed, and the target transition layer composition Cr is selected. 0.8 Cu x V 1.2 (x=0.1, 0.4).

[0029] Based on the selected target transition layer composition, a feasibility prediction diagram and phase distribution diagram of the compositional combinations of Fe, the target transition layer alloy, and the Ti alloy are calculated. Specifically, the following steps are included: Table 3 shows the Fe-Cr... 0.8 Cu x V 1.2 The component range and calculation step size table for Ti were obtained. Based on the elemental composition range and step size in Table 3, 1326 Fe-Cr elements were calculated using a Python program. 0.8 Cu x V 1.2 -Ti alloy composition; Table 3

[0030] The solidification paths of all alloy composition combinations were calculated using the Scheil-Gulliver model and the Lever Rule model respectively in high-throughput iterative calculations. Furthermore, it is derived that the combination of all components is at the melting point. An Excel file containing the phase types and phase contents; Furthermore, based on the threshold of intermetallic compound content... Based on the content of intermetallic compounds in the alloy composition and Based on the relationship between the alloy composition and the slender, the alloy composition was divided into four regions: feasible with both Scheil and Lever, feasible with Scheil but not feasible with Lever, feasible with Lever but not feasible with Scheil, and not feasible with either Scheil or Lever. Fe-Cr alloys were then constructed. 0.8 Cu x V 1.2 -Feasibility prediction diagram and phase distribution diagram of Ti alloy composition combination, thereby realizing Fe-Cr 0.8 Cu x V 1.2 -Ti gradient path design.

[0031] likeFigures 1-6 As shown, in order to further illustrate the technical solutions and effects of the present application, the present application is described with reference to the accompanying drawings: Figure 1 The process chart of the heterogeneous metal connection transition layer gradient path design method based on thermodynamic calculation. Figure 1 The main steps include generating an alloy composition; based on the Scheil-Gulliver model and the Lever Rule model, obtaining the phase composition of the alloy composition at the melting point of the alloy composition with gradient content of Fe, Ti and CrCuV; determining the transition layer composition region with high solid solubility of Fe and Ti by constructing a four-element feasibility prediction map of the alloy composition with gradient content of Fe, Ti and CrCuV; based on the selected target transition layer alloy composition, constructing a feasibility prediction map of Fe, Ti and the target transition layer alloy, and realizing the gradient path design between the base material and the target transition layer alloy.

[0032] Figure 2 The feasibility prediction map of the alloy composition with gradient content of Fe and CrCuV at the melting point of the alloy composition, almost the entire alloy composition space of CrCuV can realize high solid solubility of Fe element; Figure 3 The feasibility prediction map of the alloy composition with gradient content of Ti and CrCuV at the melting point of the alloy composition, the high solid solubility region of Ti element in the CrCuV alloy composition is mainly concentrated in the V-rich region with Cr:V less than 2:3, which indicates that high V content helps to improve the stability of the solid solution phase.

[0033] Figure 4 The CrCuV transition layer alloy composition region with high solid solubility of Fe and Ti elements and the target transition layer alloy composition. Based on the Cr:V boundary of 2:3 and the FCC+BCC dual-phase synergistic strengthening transition layer alloy design idea, by adjusting the Cu content, the target transition layer alloy composition Cr 0.8 Cu x V 1.2 (x 0.1, 0.4).

[0034] Figure 5 For example, the Cr 0.8 Cu 0.1 V 1.2 transition layer alloy composition, the feasibility prediction map of the Fe-Cr 0.8 Cu 0.1 V 1.2 -Ti alloy composition combination is constructed, and the Fe-Cr 0.8 Cu 0.1 V 1.2-Ti direct linear gradient path as shown by white arrows, indicating from Fe to Cr 0.8 Cu 0.1 V 1.2 In the gradient composition change to Ti, there are feasible gradient paths to make the intermetallic compound content within the threshold range.

[0035] Figure 6 (a) is Fe-Cr 0.8 Cu 0.1 V 1.2 and Cr 0.8 Cu 0.1 V 1.2 -Ti pseudo-binary phase diagram, it can be seen that intermetallic compounds are mainly formed on the Cr 0.8 Cu 0.1 V 1.2 -Ti side, from Figure 6 (b) and (c) are Fe-Cr 0.8 Cu 0.1 V 1.2 -Ti in the Scheil-Gulliver model and the main phase distribution diagram of Lever Rule model, it can be seen that the content of intermetallic compounds under the gradient path is very small, almost all BCC solid solution, Laves_C14 and B2 phase are mainly distributed on the Fe-Ti side.

[0036] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A gradient path design method for dissimilar metal bonding transition layers based on thermodynamic calculations, characterized in that, Includes the following steps: Step 1: Take the dissimilar metal base material and the independently controllable component units in the transition layer alloy as components, set the step size for different components, and ensure that the sum of different components is 100 at.%, to generate alloy composition combinations under the gradient content of the base material and the transition layer, which are used for thermodynamic calculations. Step 2: Combining thermodynamic calculations, high-throughput iterative calculations are performed on the alloy composition combination using the Scheil-Gulliver model and the Lever Rule model, respectively. The Scheil-Gulliver model and the Lever Rule model are used to describe the distribution law of solute elements in the alloy under non-equilibrium and equilibrium solidification conditions, respectively. Thus, the solidification path of the alloy composition combination and the melting point of all alloy composition combinations are obtained. The data on phase types and phase contents were collected, and the mole fraction of the solid solution under different models was statistically analyzed. mole fraction with intermetallic compounds ; Step 3: Based on the actual connection design requirements, specify a threshold for the content of intermetallic compounds. And there is a mole fraction under both model conditions. If the corresponding alloy composition combination is considered feasible, then it is considered feasible; otherwise, it is not feasible. Furthermore, based on the threshold With mole fraction Based on the relationship, the alloy composition combination is divided into feasible and infeasible regions, and the composition combination of the transition layer alloy is normalized to construct a feasibility prediction map of the alloy composition combination, and the composition combination regions of feasible transition layer alloys with high solid solubility in dissimilar metal base materials are screened. Step 4: Based on the obtained feasible transition layer composition combination region, select the target transition layer alloy composition, and then use the dissimilar metal base material and the target transition layer alloy as components, and calculate the feasibility prediction diagram and phase distribution diagram of dissimilar alloy connection, thus realizing the gradient path design of dissimilar alloy connection.

2. The gradient path design method for dissimilar metal connection transition layer based on thermodynamic calculations as described in claim 1, characterized in that, In step two, the Scheil-Gulliver model is applicable to predicting non-equilibrium phases formed under rapid cooling conditions. The Scheil-Gulliver model is based on the assumptions of diffusionless solid phase, homogeneous liquid phase composition, and local equilibrium at the solid-liquid interface. The basic equations of the Scheil-Gulliver model are: ， ， ， In the formula, It is the solid fraction. It is the initial component of the composition. It is composed of liquid phase. It is composed of solid phase. It is the solute partition coefficient; This yields the classic Scheil-Gulliver equation: ， 。 3. The gradient path design method for dissimilar metal connection transition layers based on thermodynamic calculations as described in claim 1, characterized in that, The Lever Rule model is applicable to predicting the equilibrium phase formed during a slow cooling process. The basic equation of the Lever Rule model is: ， ， The equation for the Lever Rule model is thus obtained as follows: ， ， In the formula, It is the solid fraction. It is the initial component of the composition. It is composed of liquid phase. It is composed of solid phase. It is the solute partition coefficient.

4. The gradient path design method for dissimilar metal connection transition layer based on thermodynamic calculations as described in claim 1, characterized in that, The specific steps of the high-throughput iterative calculation described in step two are as follows: The solidification paths for all alloy composition combinations were iteratively calculated using the Scheil-Gulliver model and the Lever Rule model, respectively, with the solid phase mole fraction set. The screening criteria are to obtain all alloy composition combinations within the melting point. Results data on phase type and phase content.

5. The gradient path design method for dissimilar metal connection transition layers based on thermodynamic calculations as described in claim 4, characterized in that, The high-throughput iterative calculations mentioned above are performed using the high-entropy alloy database panHEA and the HighThroughtput Calculation module in the Pandat software.

6. The gradient path design method for dissimilar metal connection transition layer based on thermodynamic calculations as described in claim 1, characterized in that, Step three specifically involves, based on the threshold... With mole fraction Based on the relationship, the compositional combinations of the transition layer under different matrix material gradient contents are divided into four regions: Both the Scheil-Gulliver model and the Lever Rule model have feasible regions; The Scheil-Gulliver model is feasible, while the Lever Rule model is not feasible in certain regions. The Scheil-Gulliver model is infeasible, while the Lever Rule model is feasible. Both the Scheil-Gulliver model and the Lever Rule model have infeasible regions; Next, the composition combination of the transition layer alloy was normalized, and feasibility prediction diagrams of alloy composition combinations under the gradient content changes of dissimilar metal base material and transition layer were constructed respectively. Then, the intersection of all feasible regions in the feasibility prediction map is selected to obtain a feasible transition layer composition combination region that has high solid solubility for all dissimilar metal parent materials.

7. The gradient path design method for dissimilar metal connection transition layer based on thermodynamic calculations as described in claim 1, characterized in that, In step three, independently controllable component units in the dissimilar metal base material and transition layer alloy are used as components, based on threshold values. With mole fraction Based on the relationship, the alloy composition combination is divided into feasible and infeasible regions, and a quaternary feasibility prediction diagram of the alloy composition combination under the gradient content of dissimilar metal base material and transition layer alloy is constructed respectively.

8. The gradient path design method for dissimilar metal connection transition layer based on thermodynamic calculations as described in claim 1, characterized in that, The feasibility prediction diagram for calculating dissimilar alloy bonding described in step four is a feasibility prediction diagram obtained by using dissimilar metal base material and target transition layer alloy as components, and then based on the calculation methods in steps one to three.

9. The gradient path design method for dissimilar metal connection transition layer based on thermodynamic calculations as described in any one of claims 1-8, characterized in that, The dissimilar metal base materials are titanium alloy and steel, titanium alloy and aluminum alloy, or steel and aluminum alloy, and the elements of the transition layer alloy include Cr, Cu, V, Ni or Cu, Sn, Ag or Zn, Cu, Ni.

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