Method for predicting yield strength of nickel-based polycrystalline superalloy by considering overheating

Abstract

The invention relates to a nickel-based polycrystalline superalloy yield strength prediction method considering overheating. The method comprises the following steps: acquiring material parameters of a material at different temperatures; calculating a first contribution of a material gamma matrix to the yield strength at a first overheating temperature based on the material parameters of the material at the overheating temperature according to a solid solution strengthening theory; measuring the volume fraction and the average particle size of the primary gamma'phase of the material at the overheating temperature, and calculating the second contribution of the primary gamma 'relative to the yield strength according to the correction form of the Ashby-Orowan equation; the average grain size of grains of the material at the overheating temperature is measured, and third contribution of the grain boundary to the yield strength is calculated according to the Hall-Petch relation; and constructing a yield strength prediction model, inputting the material parameters of the to-be-tested material at the to-be-tested overheating temperature, the volume fraction and the average particle size of the primary gamma'phase and the average particle size of the crystal grains into the yield strength prediction model, and outputting the yield strength of the to-be-tested material at the to-be-tested overheating temperature.

Description

Technical Field

[0001] The present application relates to the technical field of strength prediction of nickel-based polycrystalline high-temperature alloys, and in particular to a method for predicting the yield strength of nickel-based polycrystalline high-temperature alloys taking overheating into consideration. Background Art

[0002] Nickel-based polycrystalline high-temperature alloys occupy an indispensable position in the aviation and energy industries due to their excellent mechanical properties and thermal stability. They are widely used in key hot-end components such as aircraft engines and gas turbines. However, when a twin-engine or multi-engine aircraft is operating in the air, one of the engines may stop due to certain reasons, which is called a single engine inoperative (OEI). When an aircraft encounters OEI, in order to ensure flight safety, the remaining engines must adopt a short-term high-power emergency power state. At this time, the service temperature of the key components of the engine will rise sharply, and overheating will occur. The overheating process is accompanied by changes in the material microstructure and mechanical properties, which may affect the strength of the hot-end components of the aircraft engine.

[0003] At present, the prediction method for the yield strength of nickel-based polycrystalline superalloys under overheating has not been established; in addition, there is no suitable theoretical formula to quantify the contribution of different microstructure strengthening during overheating. Therefore, establishing a prediction method for the yield strength of nickel-based polycrystalline superalloys under overheating conditions in the OEI state is of great significance for ensuring the operation safety of aircraft engines under OEI conditions. Summary of the invention

[0004] Based on this, it is necessary to provide a method for predicting the yield strength of nickel-based polycrystalline high-temperature alloys based on solid solution strengthening theory, precipitation strengthening theory and grain boundary strengthening theory, specifically a method for predicting the yield strength of nickel-based polycrystalline high-temperature alloys considering overheating, the method comprising: S1: Obtaining material parameters of a material at different temperatures, wherein the material is a nickel-based polycrystalline high-temperature alloy; S2: Based on the material parameters at the superheat temperature, the material at the first superheat temperature is calculated according to the solid solution strengthening theory. c The first contribution of the matrix to the yield strength; S3: Measure the material once at superheat temperature c The volume fraction and average particle size of the phase are calculated once according to the modified form of the Ashby-Orowan equation c 'Second contribution to relative yield strength; S4: Measure the average grain size of the material at the superheated temperature and calculate the third contribution of the grain boundary to the yield strength according to the Hall-Petch relationship; S5: Integrate the first contribution, the second contribution, and the third contribution to construct a yield strength prediction model based on the base temperature. The yield strength prediction model is expressed as: ; in, Indicates the first superheat temperature T The yield strength of the lower material; Indicates the first superheat temperature T Lower material c The first contribution of the matrix to the yield strength; Indicates the first superheat temperature T Next time c 'Second contribution to relative yield strength; Indicates the first superheat temperature T The third contribution of the lower grain boundary to the yield strength; The material parameters of the material to be tested at the overheat temperature to be tested, c The volume fraction and average particle size of the phase and the average particle size of the grains are input into the yield strength prediction model, and the yield strength of the material to be tested at the overheating temperature to be tested is output.

[0005] Preferably, the material parameters of the material at different temperatures include: elastic modulus, Poisson's ratio, specific heat capacity, melting point, and shear modulus.

[0006] Preferably, the measuring method includes: The material was measured once at superheat temperature by scanning electron microscopy and electron backscatter diffraction analyzer. c 'Phase volume fraction and average particle size; The average grain size of the material at superheated temperature is measured by an electron backscatter diffraction analyzer.

[0007] Preferably, the calculation formula for the first contribution is: ; in, Indicates the first superheat temperature T Lower material c The first contribution of the matrix to the yield strength; Display material c The base temperature of the matrix contribution to yield strength; Indicates basic temperature Yield strength under Indicates that the material is at the first superheat temperature T The elastic modulus under Indicates that the material is at a reference temperature The elastic modulus under represents the specific heat capacity at constant pressure and the first superheat temperature; Indicates the melting point of the material; Indicates the material at base temperature Poisson's ratio under Indicates that the material is at the first superheat temperature T Poisson's ratio.

[0008] Preferably, the calculation formula for the second contribution is: ; in, Indicates the first superheat temperature T Next time c 'Second contribution to relative yield strength; Indicates that the material is at the first superheat temperature T Shear modulus under ; b represents the Burgers vector; Indicates the first superheat temperature T Next time c 'Volume fraction of phase (%); Indicates the first superheat temperature T Next time c 'The average particle size of the phase.

[0009] Preferably, the calculation formula of the third contribution is: ; in, Indicates the first superheat temperature T The third contribution of the lower grain boundary to the yield strength; represents the proportionality constant; Indicates that the material is at the first superheat temperature T Shear modulus under ; b represents the Burgers vector; Indicates that the material is at the first superheat temperature T The average grain size of the lower grains.

[0010] Preferably, a scanning electron microscope and an electron backscatter diffraction analyzer are used to count the sample under different overheating times. c The volume fraction and average particle size of the phase are input into the yield strength prediction model to output the yield strength of the material to be tested under different overheating times.

[0011] Preferably, an electron backscatter diffraction analyzer is used to count the average grain size of the material to be tested at different overheating times; Analyze once c 'The first variation curve of the volume fraction of the phase with the number of superheating times; Analyze the second variation curve of the average grain size of the grains with the number of overheating times; According to the first change curve, the second change curve and the yield strength under different overheating times, the yield strength under different overheating times is analyzed. c 'The contribution ratio of phase and grain boundary to yield strength changes.

[0012] Preferably, the Burgers vector value is 2.54 nm.

[0013] Beneficial effect: This method combines the three theoretical foundations of solid solution strengthening theory, precipitation strengthening theory and grain boundary strengthening theory with the superheated temperature c The yield strength prediction model of nickel-based polycrystalline high-temperature alloy at basic temperature was constructed by combining the volume fraction of the phase, the average particle size and the average particle size of the grains. An effective method to quantify the strength contribution of different microstructures during overheating was proposed, which provided theoretical guidance for the design of high-performance nickel-based polycrystalline high-temperature alloys under extreme environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 This is a flow chart of a method for predicting the yield strength of a nickel-based polycrystalline high-temperature alloy taking overheating into account in an embodiment of the present application.

[0016] Figure 2 This is a schematic diagram of OEI processing in an embodiment of the present application.

[0017] Figure 3 In this application example, c 'The volume fraction of the phase changes with the superheat temperature.

[0018] Figure 4 Graph showing the average grain size of the crystals in the embodiment of the present application as a function of the overheating temperature. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0021] like Figure 1 As shown, this embodiment provides a method for predicting the yield strength of a nickel-based polycrystalline high-temperature alloy taking overheating into consideration, the method comprising: S1: Obtain material parameters of a material at different temperatures, where the material is a nickel-based polycrystalline high-temperature alloy.

[0022] In this embodiment, material parameters of the material at different temperatures include but are not limited to: elastic modulus, Poisson's ratio, specific heat capacity, melting point, and shear modulus.

[0023] S2: Based on the material parameters at the superheat temperature, the material at the first superheat temperature is calculated according to the solid solution strengthening theory. c The first contribution of the matrix to the yield strength.

[0024] In this embodiment, the measuring method includes: The material was measured once at superheat temperature by scanning electron microscopy and electron backscatter diffraction analyzer. c 'Phase volume fraction and average particle size; The average grain size of the material at superheated temperature is measured by an electron backscatter diffraction analyzer.

[0025] The solid solution strengthening theory is that the alloying elements dissolve in the matrix metal to cause a certain degree of lattice distortion, thereby improving the strength of the alloy; specifically, the solute atoms dissolved in the solid solution cause lattice distortion, which increases the resistance to dislocation movement and hinders crystal slip, thereby improving the strength of the alloy solid solution.

[0026] Furthermore, the calculation formula of the first contribution is: ; in, Indicates the first superheat temperature T Lower material c The first contribution of the matrix to the yield strength; Display material c The base temperature of the matrix contribution to yield strength; Indicates basic temperature Yield strength under Indicates that the material is at the first superheat temperature T The elastic modulus under Indicates that the material is at a reference temperature The elastic modulus under represents the specific heat capacity at constant pressure and the first superheat temperature; Indicates the melting point of the material; Indicates the material at base temperature Poisson's ratio under Indicates that the material is at the first superheat temperature T Poisson's ratio.

[0027] In this embodiment, the nickel-based polycrystalline high-temperature alloy takes GH4720Li alloy as an example. The GH4720Li alloy contains 16% Cr and 1.25% W solid solution strengthening elements. Three different sizes of nickel-based polycrystalline high-temperature alloys are formed by sub-solution heat treatment at 1100°C. c 'Strengthen the phase and c Matrix, according to the solid solution strengthening theory, the solid solution elements in the alloy dissolve in the matrix metal at the corresponding temperature, strengthening c Matrix strength.

[0028] This calculation formula is based on an equivalent relationship between thermal energy and torsional strain energy and is used to calculate the temperature-dependent yield strength of metal materials at any temperature. As material c Base temperature of the matrix contribution to yield strength.

[0029] According to the solid solution strengthening theory, the material forms a c Solid solutions such as the matrix remain thermally stable at the corresponding temperature, which provides dislocation resistance and thus improves the yield strength of the material. Therefore, referring to the above calculation formula, the yield strength at different temperatures is calculated based on the base temperature. c The contribution of the matrix to the yield strength is reasonable.

[0030] S3: Measure the material once at superheat temperature c The volume fraction and average particle size of the phase are calculated once according to the modified form of the Ashby-Orowan equation c 'The second contribution to the relative yield strength.

[0031] Spherical primary c 'phase is mainly distributed at the grain boundary, playing the role of "pinning" the grain boundary and inhibiting c The matrix movement also hinders the dislocation movement and thus improves the material strength. c 'The phase strength is high, and the dislocation cannot be cut once when the material undergoes plastic deformation c 'phase can only bypass the mechanism, which is called Orowan precipitation strengthening mechanism and was introduced by Ashby into the randomly dispersed precipitation phase; therefore, in this embodiment, once c'The second contribution to the relative yield strength is quantified using a modified form of the Ashby-Orowan equation.

[0032] Specifically, the calculation formula for the second contribution is: ; in, Indicates the first superheat temperature T Next time c 'Second contribution to relative yield strength; Indicates that the material is at the first superheat temperature T Shear modulus under (GPa); b represents the Burgers vector; Indicates the first superheat temperature T Next time c 'Volume fraction of phase (%); Indicates the first superheat temperature T Next time c 'The average particle size of the phase (nm).

[0033] S4: Measure the average grain size of the material at superheat temperature and calculate the third contribution of grain boundaries to yield strength based on the Hall-Petch relationship.

[0034] The Hall-Petch relationship is an important theoretical model based on dislocation theory, which is widely used to explain the mechanical properties of polycrystalline materials. It describes how the grain size of a crystalline material affects its yield strength; it shows that smaller grain sizes can lead to higher yield strengths due to the increased difficulty of dislocation movement. The theoretical basis of this relationship is that the crystallographic orientations between grains are different, and the grain boundaries act as obstacles to dislocation movement. The smaller the grains, the larger the total grain boundary area, making it more difficult for dislocations to move in the material, thereby increasing strength.

[0035] The expression of the Hall-Petch relationship is: ; in, Indicates the yield strength of the material; Indicates the yield strength of the material excluding the strength increased by grain boundary strengthening; It represents a constant related to material properties, reflecting the effectiveness of grain boundaries in hindering dislocation motion; D It represents the average grain size; According to the Hall-Petch relationship, Materials c The matrix and once c 'The first contribution and the second contribution to the relative yield strength are provided, so the second term is used as the calculation formula for the third contribution of the grain boundary to the yield strength related to temperature, where the constants related to the material properties are replaced Use parameters Replacement, average grain size D The material is at the first superheat temperature T The average grain size of the lower grain Substitute and get the calculation formula for the third contribution.

[0036] Specifically, the calculation formula of the third contribution is: ; in, Indicates the first superheat temperature T The third contribution of the lower grain boundary to the yield strength; represents the proportionality constant; Indicates that the material is at the first superheat temperature T Shear modulus under ; b represents the Burgers vector; Indicates that the material is at the first superheat temperature T The average grain size (nm) of the following grains.

[0037] S5: Integrate the first contribution, the second contribution, and the third contribution to construct a yield strength prediction model based on a base temperature; According to the above Hall-Petch relationship, combined with the material c The matrix and once c 'The first contribution, second contribution of relative yield strength, and the temperature-related third contribution of grain boundary to yield strength are used to construct a yield strength prediction model for nickel-based polycrystalline high-temperature alloys at basic temperature.

[0038] The expression of the yield strength prediction model is: ; in, Indicates the first superheat temperature T The yield strength of the lower material; Indicates the first superheat temperature T Lower material c The first contribution of the matrix to the yield strength; Indicates the first superheat temperature T Next time c 'Second contribution to relative yield strength; Indicates the first superheat temperature T The third contribution of the lower grain boundary to the yield strength.

[0039] The material parameters of the material to be tested at the overheat temperature to be tested, c The volume fraction and average particle size of the phase and the average particle size of the grains are input into the yield strength prediction model, and the yield strength of the material to be tested at the overheating temperature to be tested is output.

[0040] In this embodiment, it also includes: using a scanning electron microscope and an electron backscatter diffraction analyzer to count the number of times the material to be tested is overheated. c 'The volume fraction and average particle size of the phase are input into the yield strength prediction model to output the yield strength of the material to be tested under different overheating times; The average grain size of the tested material at different overheating times is counted by an electron backscatter diffraction analyzer; Analyze once c 'The first variation curve of the volume fraction of the phase with the number of superheating times; Analyze the second variation curve of the average grain size of the grains with the number of overheating times; According to the first change curve, the second change curve and the yield strength under different overheating times, the yield strength under different overheating times is analyzed. c 'The contribution ratio of phase and grain boundary to yield strength changes.

[0041] In this embodiment, the first superheating temperature is 800°C. T , overheated 0 times, 1 time, 2 times, 8 times, and recorded the material under different overheating times c base, once c The contribution of phase and grain boundary to yield strength is compared under different overheating times. The proportion of the first contribution, the second contribution, and the third contribution are obtained to obtain the material under different overheating times. c base, once c 'The contribution ratio of phase and grain boundary to yield strength changes.

[0042] Among them, the yield strength prediction model under different overheating times can be expressed as: ; in, Indicates the first overheat temperature at different times T The yield strength of the lower material; Indicates the first overheat temperature at different times T Lower material c The first contribution of the matrix to the yield strength; Indicates the first overheat temperature at different times T Next time c 'Second contribution to relative yield strength; Indicates the first overheat temperature at different times T The third contribution of the lower grain boundary to the yield strength.

[0043] This embodiment takes the nickel-based polycrystalline high-temperature alloy GH4720Li as an example, and uses the experimental data of the high-temperature stretching process after overheating treatment to perform a test experiment. The material parameters used in the test experiment are shown in Table 1.

[0044] Table 1 is the material parameter table of GH4720Li alloy; ; Table 1 shows the material parameters of GH4720Li alloy. The melting point of GH4720Li alloy is usually 1330℃, and the Burgers vector is b =2.54nm.

[0045] The GH4720Li alloy tensile specimens were subjected to overheat treatment. Figure 2 The specific processing flow of OEI processing is as follows: Firstly, the alloy tensile specimen was slowly heated to 400°C, and the stress was simultaneously loaded to 350 MPa, and the load was maintained for 5 minutes. Secondly, the temperature was rapidly increased to the target temperature at a temperature rise rate of 60°C / s, and the stress was simultaneously loaded to 700 MPa, and the load was maintained for 30 seconds, and then the specimen was unloaded and air-cooled to room temperature.

[0046] Take a photo of the alloy tensile specimens at different overheating temperatures. c The scanning electron microscope photograph of the phase was taken, and the electron backscatter diffraction analyzer was used to measure and count the number of phases in the alloy tensile specimen at each overheating temperature. c The volume fraction and average particle size of the phase were statistically obtained in the alloy tensile specimen. c The curve of the volume fraction of the phase changing with the superheat temperature is as follows: Figure 3 shown.

[0047] Analysis of alloy tensile specimens at different overheating temperatures c 'The volume fraction of the phase, the first fitting curve is obtained, the expression is: ; in, Indicates once c 'Volume fraction of phase; T Indicates the first superheat temperature.

[0048] The average grain size of the alloy tensile specimen at each overheating temperature was measured and counted using an electron backscatter diffraction analyzer, and a curve showing the average grain size of the alloy tensile specimen changing with the overheating temperature was obtained. Figure 4 shown.

[0049] The average grain size of the alloy tensile specimens at different overheating temperatures was analyzed to obtain the second fitting curve, which is expressed as follows: D =2.62+0.00216 T ; in, D Indicates the average grain size.

[0050] Taking 400℃ as the base temperature, the yield strength of GH4720Li alloy at different overheating temperatures was predicted. The first prediction result is shown in Table 2.

[0051] Table 2 is the first prediction result table of yield strength of GH4720Li alloy at different overheating temperatures; ; Taking the overheating temperature of 800℃ as the basic temperature of a single overheating treatment, the scanning electron microscope and electron backscatter diffraction analyzer were used to analyze the next overheating times. c 'The relationship between the volume fraction and average particle size of the phase and the number of overheating times, the next time at different overheating times c The volume fraction and average particle size of the phase are shown in Table 3.

[0052] Table 3 shows the results of GH4720Li alloy under different overheating times. c 'Specific data table of phase volume fraction and average particle size; ; The data recorded in Table 3 is input into the yield strength prediction model to predict the yield strength of the nickel-based polycrystalline high-temperature alloy under different overheating times. The second prediction result table is shown in Table 4.

[0053] Table 4 is a second prediction result table of yield strength of GH4720Li alloy under different overheating times; ; It can be seen from Tables 2 and 4 that the yield strength prediction model of the nickel-based polycrystalline high-temperature alloy based on the basic temperature constructed in this embodiment can not only predict the yield strength of the nickel-based polycrystalline high-temperature alloy at different overheating temperatures, but also predict the yield strength of the nickel-based polycrystalline high-temperature alloy after multiple overheating treatments, and the overall prediction error is within 4%, with high prediction accuracy.

[0054] The method for predicting the yield strength of nickel-based polycrystalline high-temperature alloys taking overheating into consideration provided in this embodiment has the following beneficial effects: 1. This method combines the three theoretical foundations of solid solution strengthening theory, precipitation strengthening theory and grain boundary strengthening theory with the superheated temperature c The yield strength prediction model of nickel-based polycrystalline high-temperature alloy at basic temperature was constructed by combining the volume fraction of the phase, the average particle size and the average particle size of the grains. An effective method to quantify the strength contribution of different microstructures during overheating was proposed, which provided theoretical guidance for the design of high-performance nickel-based polycrystalline high-temperature alloys under extreme environments.

[0055] 2. Taking the nickel-based polycrystalline high-temperature alloy GH4720Li as an example, the experimental data of the high-temperature tensile process after overheating treatment was used, and the qualitative and quantitative relationship of the alloy strength was calculated through the strength theoretical model in the prediction method. The predicted yield strength is consistent with the experimental results. The relevant strengthening theory analyzed is of great significance for studying and analyzing the changes in the strength of nickel-based polycrystalline high-temperature alloys during the overheating process.

[0056] 3. This method can be used to analyze the nickel-based polycrystalline high-temperature alloy under different overheating times. c The first change curve of the volume fraction of the phase is calculated, and combined with the quantitative measurement of the average grain size of the grains, the influence of different overheating times on the yield strength of the nickel-based polycrystalline high-temperature alloy is studied, which provides theoretical guidance for analyzing the strengthening of nickel-based polycrystalline high-temperature alloys under overheating conditions.

[0057] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for predicting the yield strength of a nickel-based polycrystalline high-temperature alloy taking overheating into account, characterized in that: include: S1: Obtaining material parameters of a material at different temperatures, wherein the material is a nickel-based polycrystalline high-temperature alloy; S2: Based on the material parameters at the superheat temperature, the material at the first superheat temperature is calculated according to the solid solution strengthening theory. γ The first contribution of the matrix to the yield strength; S3: Measure the material once at superheat temperature γ The volume fraction and average particle size of the phase are calculated once according to the modified form of the Ashby-Orowan equation γ 'Second contribution to relative yield strength; S4: Measure the average grain size of the material at the superheated temperature and calculate the third contribution of the grain boundary to the yield strength according to the Hall-Petch relationship; S5: Integrate the first contribution, the second contribution, and the third contribution to construct a yield strength prediction model based on the base temperature. The yield strength prediction model is expressed as: ； in, Indicates the first superheat temperature T The yield strength of the lower material; Indicates the first superheat temperature T Lower material γ The first contribution of the matrix to the yield strength; Indicates the first superheat temperature T Next time γ 'Second contribution to relative yield strength; Indicates the first superheat temperature T The third contribution of the lower grain boundary to the yield strength; The material parameters of the material to be tested at the overheat temperature to be tested, γ The volume fraction and average particle size of the phase and the average particle size of the grains are input into the yield strength prediction model, and the yield strength of the material to be tested at the overheating temperature to be tested is output.

2. The method for predicting the yield strength of a nickel-based polycrystalline high-temperature alloy considering overheating according to claim 1, characterized in that: The material parameters of the material at different temperatures include: elastic modulus, Poisson's ratio, specific heat capacity, melting point, and shear modulus.

3. The method for predicting the yield strength of nickel-based polycrystalline high-temperature alloys considering overheating according to claim 1, characterized in that: Measurement methods include: The material was measured once at superheat temperature by scanning electron microscopy and electron backscatter diffraction analyzer. γ 'Phase volume fraction and average particle size; The average grain size of the material at superheated temperature is measured by an electron backscatter diffraction analyzer.

4. The method for predicting the yield strength of a nickel-based polycrystalline high-temperature alloy taking overheating into consideration according to claim 2, characterized in that: The calculation formula for the first contribution is: ； in, Indicates the first superheat temperature T Lower material γ The first contribution of the matrix to the yield strength; Display material γ The base temperature of the matrix contribution to yield strength; Indicates basic temperature Yield strength under Indicates that the material is at the first superheat temperature T The elastic modulus under Indicates that the material is at a reference temperature The elastic modulus under represents the specific heat capacity at constant pressure and the first superheat temperature; Indicates the melting point of the material; Indicates the material at base temperature Poisson's ratio under Indicates that the material is at the first superheat temperature T Poisson's ratio.

5. The method for predicting the yield strength of nickel-based polycrystalline high-temperature alloy considering overheating according to claim 4, characterized in that: The calculation formula for the second contribution is: ； in, Indicates the first superheat temperature T Next time γ 'Second contribution to relative yield strength; Indicates that the material is at the first superheat temperature T Shear modulus under ; b represents the Burgers vector; Indicates the first superheat temperature T Next time γ 'Volume fraction of phase; Indicates the first superheat temperature T Next time γ 'The average particle size of the phase.

6. The method for predicting the yield strength of nickel-based polycrystalline high-temperature alloy considering overheating according to claim 5, characterized in that: The calculation formula for the third contribution is: ； in, Indicates the first superheat temperature T The third contribution of the lower grain boundary to the yield strength; represents the proportionality constant; Indicates that the material is at the first superheat temperature T Shear modulus under ; b represents the Burgers vector; Indicates that the material is at the first superheat temperature T The average grain size of the lower grains.

7. The method for predicting the yield strength of nickel-based polycrystalline high-temperature alloy considering overheating according to claim 3, characterized in that: The scanning electron microscope and electron backscatter diffraction analyzer were used to count the changes of the material under different overheating times. γ The volume fraction and average particle size of the phase are input into the yield strength prediction model to output the yield strength of the material to be tested under different overheating times.

8. The method for predicting the yield strength of nickel-based polycrystalline high-temperature alloy considering overheating according to claim 7, characterized in that: The average grain size of the tested material at different overheating times is counted by an electron backscatter diffraction analyzer; Analyze once γ 'The first variation curve of the volume fraction of the phase with the number of superheating times; Analyze the second variation curve of the average grain size of the grains with the number of overheating times; According to the first change curve, the second change curve and the yield strength under different overheating times, the yield strength under different overheating times is analyzed. γ 'The contribution ratio of phase and grain boundary to yield strength changes.

9. The method for predicting the yield strength of nickel-based polycrystalline high-temperature alloy considering overheating according to claim 6, characterized in that: The Burgers vector value is 2.54nm.

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