Method for evaluating creep property of nickel-based single-crystal high-temperature alloy blade based on microstructure characteristics and crystal plasticity theory

Abstract

The invention provides a method for evaluating the creep property improvement effect of a single crystal blade by a heat treatment process, which comprises the following steps of: quantitatively observing the microstructure of an as-cast nickel-based single crystal high-temperature alloy material which is not subjected to heat treatment and a nickel-based single crystal high-temperature alloy material which is subjected to different heat treatment systems; acquiring a creep curve of the alloy; obtaining the critical slitting stress of the alloy; constructing a creep constitutive equation and a creep damage equation of the nickel-based single-crystal high-temperature alloy material; obtaining a prediction equation of the creep life of the nickel-based single-crystal high-temperature alloy; establishing a mapping relationship between the strengthening phase size, the volume fraction and the cubic degree of the alloy and the critical slitting stress and the initial creep damage rate; and the mapping relation of the strengthening phase volume fraction, the cubic degree and the creep life under different heat treatments is obtained, the creep life of the nickel-based single-crystal high-temperature alloy material subjected to heat treatment under different service conditions is predicted, and the problem that quantitative evaluation of heat treatment for quantification of single-crystal turbine blade creep performance improvement is lacked in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of nickel-based single-crystal superalloy blades for aero-engines and gas turbines. Specifically, it relates to a method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory. This method is particularly suitable for quantitatively evaluating the effect of different heat treatment processes on improving the creep life of single-crystal turbine blades. Background Technology

[0002] Nickel-based single-crystal superalloys possess excellent mechanical properties such as creep resistance, fatigue resistance, and oxidation resistance at high temperatures, and are widely used in the manufacture of turbine blades for aero-engines and gas turbines. The high-temperature strength of nickel-based single-crystal superalloys mainly originates from their highly ordered, coherent L12 structure intermetallic compounds—the γ' phase (Ni3Al, Ni3Ti). These γ' phase particles are dispersed in the γ matrix (nickel-based solid solution), effectively hindering dislocation movement. At high temperatures, dislocations pass through the γ' phase via a mechanism called "dislocation pair cutting." The strength of resistance to this cutting ability directly determines the yield strength of the alloy. The purpose of heat treatment is to transform the alloy from an unstable, inhomogeneous structure in the as-cast state into a structure with γ' phases of optimal size, morphology, volume fraction, and distribution through processes such as solution treatment and aging.

[0003] Typical heat treatment processes include: (1) Solution treatment: The alloy is heated to a temperature above which the γ' phase completely dissolves and held at that temperature. The purpose is to eliminate interdendritic segregation in the as-cast state and homogenize the composition; dissolve the initial irregular γ' phase; and create uniform supersaturated solid solution conditions for subsequent aging precipitation. (2) Aging treatment (first and second stage): The alloy is held at a lower temperature to allow the γ' phase to precipitate uniformly from the supersaturated matrix in a fine, cubic morphology. First stage aging (higher temperature): A coarser cubic γ' phase is formed, which is the main strengthening phase. Second stage aging (lower temperature): A finer spherical γ” phase is formed between the γ' phases of the first stage aging, providing additional strengthening.

[0004] The effect of heat treatment on creep strengthening of single-crystal blades still needs further clarification. It is urgent to establish an evaluation method for the creep strengthening effect of heat treatment on single-crystal blades, and to establish a mapping relationship between the optimization of alloy microstructure under heat treatment and the improvement of service life of high-temperature alloys. This will provide important theoretical basis for the application of single-crystal high-temperature alloy blades and the optimization of heat treatment processes. Summary of the Invention

[0005] The main objective of this invention is to provide a method for evaluating the effect of heat treatment on the creep performance of single-crystal blades, so as to solve the problem in the prior art of lacking a quantitative assessment of the mapping between the microstructure morphology and mechanical properties of single crystals after heat treatment.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory is provided, characterized by comprising the following steps: Step S1, Microstructure characteristics acquisition: Obtain microstructure images of untreated as-cast nickel-based single-crystal superalloy materials and nickel-based single-crystal superalloy materials after different heat treatment regimes, and extract the size, volume fraction and cubicity of the γ′ strengthening phase from them. Step S2, Macroscopic creep performance test: Through creep test, obtain the creep curves of untreated cast nickel-based single crystal superalloy material and nickel-based single crystal superalloy material after different heat treatment regimes, and extract information such as initial creep damage rate and creep life from them; Step S3, Critical Shear Stress Test: The critical shear stress of untreated cast nickel-based single-crystal superalloy materials and nickel-based single-crystal superalloy materials after different heat treatment regimes is obtained through tensile tests. Step S4, Construction of Crystal Plastic Creep Damage Model: Based on crystal plasticity theory, construct the creep constitutive equation and creep damage equation for coupled damage; among which, The creep constitutive equation is: ; The creep damage equation is as follows: ; In the formula, For the sliding system that is in operation, for Damage to slip system Damage rate of slip system For the shear stress of the slip system, For the creep shear strain rate of the slip system, These are the parameters for the second creep curve. The initial creep damage rate, The critical shear stress; A These are the parameters for the first creep curve. The parameters for the third creep curve are... These are the parameters for the fourth creep curve; Step S5, Derivation of the creep life prediction equation: Integrating the creep damage equation constructed in step S4, the explicit creep life prediction equation is derived, as follows: In the formula, For creep life, N is the number of slip surface opening directions in a slip system; Step S6: Establish the mapping relationship between the volume fraction of the strengthening phase, cubicity, critical shear stress, and initial creep damage rate of untreated cast nickel-based single crystal superalloy materials and nickel-based single crystal superalloy materials after different heat treatment regimes. Step S7: Obtain the mapping relationship between the volume fraction and cubicity of the strengthening phase and the creep life under different heat treatments, and predict the creep life of the heat-treated nickel-based single crystal superalloy material under different service conditions.

[0007] Furthermore, the cubicity of the γ′ strengthening phase in step S1 is determined by the shape parameter ( The volume fraction of the γ′ strengthening phase is measured by polishing and etching the single crystal alloy, taking microscopic images using a scanning electron microscope, and then using image processing software to automatically calculate the volume fraction of the γ′ phase based on the difference in contrast between the γ′ phase and the γ phase.

[0008] Furthermore, step S4 involves constructing the creep constitutive equation and creep damage equation for nickel-based single-crystal superalloy materials, including the following steps: Based on the aforementioned crystal plasticity theory, and according to the correspondence between the shear strain rate of the slip system and the partial shear stress of the slip system, the creep constitutive equation is established: ; Based on the crystal plasticity theory, and according to the correspondence between creep damage, slip system shear stress, and cumulative creep damage, the creep damage equation is established: ; Furthermore, the slip system shear stress of the nickel-based single-crystal superalloy material described in step S4... It can be obtained through the following formula: ; ; Let σ be the orientation factor, and σ be the stress tensor in the crystal axis system. Let be the slip direction of the slip system, and Let be the unit normal vector of the slip surface in the slip system.

[0009] Furthermore, the slip system is selected from the octahedral slip system.

[0010] Furthermore, N is 12.

[0011] Further, in step S2, based on the creep damage equation, the creep life prediction equation for nickel-based single-crystal superalloys is obtained, including the following steps: Based on the creep damage equation described in step S1, the creep life prediction equation is obtained by integrating the damage rate from 0 to 1.

[0012] .

[0013] Further, step S3, which involves obtaining the critical shear stress of untreated cast nickel-based single-crystal superalloy material and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes through tensile testing, includes the following steps: Tensile tests were performed on the untreated as-cast nickel-based single-crystal superalloy material and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes to obtain tensile curves. Based on the tensile curve, the yield strength of the untreated as-cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy materials subjected to different heat treatment regimes are obtained. Based on the yield strength and crystal plasticity theory, the critical shear stress of the slip system is obtained. .

[0014] Furthermore, the steps in step S4 for obtaining the initial creep damage rate and creep curve parameters of the untreated cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy materials after different heat treatment regimes through creep testing are as follows: Creep tests were conducted on the untreated as-cast nickel-based single-crystal superalloy material and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes under different stresses to obtain creep curves; Based on the creep curves, creep curve parameters were obtained for the untreated cast nickel-based single-crystal superalloy material and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes. .

[0015] Based on the creep curves, creep curve parameters were obtained for the untreated cast nickel-based single-crystal superalloy material and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes, including A. , , .

[0016] Furthermore, the step S6, which establishes the mapping relationship between the strengthening phase size, volume fraction, cubicity, critical shear stress, and initial creep damage rate of untreated cast nickel-based single-crystal superalloy materials and nickel-based single-crystal superalloy materials treated with different heat treatment regimes, includes the following steps: Based on the initial creep damage rate Critical shear stress Volume fraction of strengthening phase The relationship between cubicity η and the following mapping relationship is established: The parameters x1 (range 0~100), x2 (range 0~200), y1 (range 0~1), and y2 (range 0~1) are based on... ,and ,as well as , The relationship was obtained.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) By systematically integrating microstructure characterization, macroscopic mechanical testing and crystal plasticity theory into a unified framework, cross-scale prediction from nano / microscale microstructure characteristics to macroscopic service life has been achieved.

[0018] 2) The volume fraction and cubicity of the γ′ strengthening phase and the two core parameters that determine the creep resistance of the material—critical slit shear stress—were established. and initial creep damage rate The explicit mathematical mapping relationship between them allows the microstructure control effect of heat treatment process to be directly quantified as the input parameters in the constitutive model.

[0019] 3) The constructed creep damage equation and life prediction equation are based on physical mechanisms such as dislocation slip and damage accumulation. They not only have predictive capabilities, but also have stronger extrapolation and universality, and can be applied to different heat treatment states and service conditions. Attached Figure Description

[0020] Figure 1 It is an enhanced method for calculating the cubicity of phase. Figure 2 This is a flowchart of the method of the present invention. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but this should not limit the scope of protection of the present invention.

[0022] As described in the background section, existing technologies lack the ability to quantitatively assess the creep-improving effect of heat treatment on single-crystal superalloy blades. To address this issue, this invention provides a method for evaluating the effect of heat treatment processes on improving the creep performance of single-crystal blades, such as... Figure 2 As shown, it includes the following steps: Phase 1: Model Building and Calibration Step S1: Prepare the sample and obtain microstructure parameters. 1. Material Selection: A second-generation nickel-based single-crystal superalloy was selected, with the following chemical composition (mass percentage): Cr 6.5%, Co 9%, W 6%, Al 5.6%, Ti 1%, Ta 6.5%, Mo 0.6%, Re 3%, Ni balance. All samples were taken from

[001] oriented single-crystal rods.

[0023] 2. Heat treatment design: Design at least three different heat treatment regimes: State A (cast state): without any heat treatment, used as a benchmark for performance comparison.

[0024] Condition B (Standard Heat Treatment): The conventional solution treatment + two-stage aging process in this field is adopted.

[0025] State C (Optimized heat treatment): Based on the standard process, the aging temperature or time is adjusted in order to obtain different γ′ phase morphologies.

[0026] 3. Microstructure Characterization: After standard metallographic preparation (polishing, etching), the microstructure of samples in each state was observed using a scanning electron microscope (SEM) in backscatter mode. Using image analysis software (such as Image-Pro Plus, ImageJ), based on the contrast difference between the γ′ phase (dark contrast) and the γ matrix (bright contrast), the average area fraction of the γ′ phase was automatically calculated across at least five fields of view, which was considered the volume fraction ρ. At least 50 regular γ′ phase particles were randomly selected for measurement. For a single γ′ phase, its actual projected width B was measured, and the projected side length B′ of its circumscribed ideal cube in that direction was determined. The cubicity of a single particle was calculated using the formula η = B′ / B, and the average value of all measured particles was taken as the cubicity η for that state. The closer the η value is to 1, the higher the cubicity.

[0027] Step 2: Obtain key performance parameters Step S2.1 Based on the crystal plasticity theory, construct the creep constitutive equation and creep damage equation for nickel-based single-crystal superalloy materials; Step S2.2: Based on the creep damage equation, obtain the creep life prediction equation for nickel-based single-crystal superalloys; Step S2.3: Through tensile testing, obtain the critical shear stress of the untreated cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy materials after different heat treatment regimes; Step S2.4: Obtain the initial creep damage rate and creep curve parameters of untreated cast nickel-based single crystal superalloy material and nickel-based single crystal superalloy material after different heat treatment regimes through creep tests. The creep constitutive equation is: ; The creep damage equation is as follows: ; The creep life prediction equation is as follows: ; in, For the sliding system that is in operation, for Damage to slip system Damage rate of slip system For the shear stress of the slip system, For the creep shear strain rate of the slip system, The creep life is given by N, which is the number of slip surface opening directions in a slip system.

[0028] The initial creep damage rate, The critical shear stress is the initial creep damage rate and the critical shear stress. These are related to the size, volume fraction, and cubicity of the strengthening phase.

[0029] A represents the parameters of the first creep curve. These are the parameters for the second creep curve. The parameters for the third creep curve are... These are the parameters for the fourth creep curve. These creep curve parameters are only related to the single-crystal alloy material and the creep temperature, and are independent of the size, volume fraction, and cubicity of the strengthening phase.

[0030] Step S2.5: Obtain the size, volume fraction, and cubicity of the reinforcing phase of the untreated as-cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy material after different heat treatment regimes by scanning electron microscopy. Step 3: Establish quantitative mapping relationship and lifetime prediction model Step S3: Establish the mapping relationship between the strengthening phase size, volume fraction, cubicity, critical shear stress, and initial creep damage rate of untreated cast nickel-based single-crystal superalloy materials and nickel-based single-crystal superalloy materials after different heat treatment regimes.

[0031] Phase Two: Life Prediction and Assessment Step 4: Apply the model for prediction and evaluation Based on the mapping relationship between the strengthening phase size, volume fraction, cubicity and critical shear stress, initial creep damage rate, and the creep life prediction equation, the mapping relationship between the strengthening phase size, volume fraction, cubicity and creep life before and after heat treatment is obtained, and the creep life of nickel-based single crystal superalloy materials before and after heat treatment under different service conditions is predicted.

[0032] Step S1 establishes the creep constitutive equation and creep damage equation for the single-crystal alloy material, including the following steps: Based on the crystal plasticity theory, and according to the correspondence between the shear strain rate of the slip system and the shear stress of the slip system, the creep constitutive equation is established; based on the crystal plasticity theory, and according to the correspondence between creep damage, the shear stress of the slip system, and cumulative creep damage, the creep damage equation is established. The slip system shear stress of the nickel-based single-crystal superalloy material in step S1 It can be obtained through the following formula: ; ; Let σ be the orientation factor, and σ be the stress tensor in the crystal axis system. Let be the slip direction of the slip system, and Let be the unit normal vector of the slip surface in the slip system. Both can be derived from the slip system activation law of nickel-based single crystal alloys, which will not be described in detail here.

[0033] In step S1, the constitutive model of the nickel-based single-crystal superalloy material can be characterized by the creep strain rate, which can be denoted as: And satisfy the following relationship: = ; In the formula, For macroscopic strain rate, and Let be the strain rate of the elastic component. Let be the strain rate of the inelastic portion, and ; Next, decompose the creep strain: ; in, This corresponds to the creep strain of the hexahedral slip system. This corresponds to the creep strain of the octahedral slip system. This corresponds to the dodecahedral slip system. If any slip system is not activated, the corresponding value is zero. For the creep of nickel-based single-crystal superalloy turbine blades, and It is zero.

[0034] in addition, For anisotropic elastic tensors, they can be expressed in matrix form: ; For nickel-based single-crystal alloys, C11, C12, and C44 are three independent elastic constants, and C 11 =1 / E, C 12 =-μ / E,C44 =1 / G, where E is the elastic modulus, μ is Poisson's ratio, and G is the shear modulus.

[0035] In this embodiment, the slip system is selected from the octahedral slip system, and N=12.

[0036] Critical shear stress This refers to the maximum stress at which a material undergoes plastic deformation and crack propagation due to an external load, but does not break. In a preferred embodiment, step S3 involves obtaining the yield strength of untreated cast nickel-based single-crystal superalloy material and nickel-based single-crystal superalloy material after different heat treatment regimes through a tensile test, thereby obtaining the critical shear stress.

[0037] In a preferred embodiment, the steps of obtaining the initial creep damage rate and creep curve parameters of the nickel-based single-crystal superalloy material in step S4 are as follows: creep tests are conducted on the untreated cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy material after different heat treatment regimes to obtain the creep curves; The initial creep damage rates of the untreated cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy materials subjected to different heat treatment regimes were obtained based on the creep curves. .

[0038] Based on the creep curves, creep curve parameters were obtained for the untreated cast nickel-based single-crystal superalloy material and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes, including A. , , .

[0039] In a preferred embodiment, the untreated as-cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy material treated with different heat treatment regimes have the same chemical composition. The size, volume fraction, and cubicity of the strengthening phase of the single-crystal superalloy before and after heat treatment are obtained using scanning electron microscopy. Based on the mapping relationship between the size, volume fraction, and cubicity of the strengthening phase and the critical shear stress and initial creep damage rate, and the creep life prediction equation, the mapping relationship between the size, volume fraction, and cubicity of the strengthening phase and the creep life before and after heat treatment is obtained, and the creep life of the nickel-based single-crystal superalloy material before and after heat treatment is predicted under different service conditions. The predicted values ​​are closer to the actual values, and the accuracy is higher.

[0040] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0041] Example 1 Untreated as-cast nickel-based single-crystal superalloy samples were selected for model construction (denoted as model samples). Creep curve parameters A, n, and χ of the as-cast nickel-based single-crystal superalloy model samples under specific conditions (980℃ / 250MPa) were obtained through creep experiments. Compared with the initial creep damage rate The critical shear stress of a model specimen of nickel-based single-crystal superalloy material under as-cast conditions was obtained by tensile testing. As shown in Table 1; then, for nickel-based single-crystal superalloy materials after different heat treatments, their elastic modulus E, Poisson's ratio, and shear modulus are not significantly different from those of the original materials, and are approximately the same, as shown in Table 2; creep tests and tensile tests were conducted to obtain the values ​​of test sample 1 (heat treatment 1) and test sample 2 (heat treatment 2). and See Table 2 for details; the creep curve parameters A, n, and χ of test samples 1 and 2 are shown in Table 2. and creep damage rate Shear stress of slip system Substituting the creep life prediction equation, the creep life of test samples 1 and 2 is obtained and recorded as the creep life prediction value. At the same time, the creep curves of the two test samples under specific conditions (the same conditions as the model sample) are measured by experimental measurement to obtain the true creep life value. The creep life prediction value and the true creep life value of the two test samples are shown in Table 2. The model sample, test sample 1 and test sample 2 have the same composition, as shown in Table 3. Table 1. Creep curve parameters, initial creep damage rate, critical shear stress, and volume fraction of strengthening phase in untreated cast nickel-based single-crystal superalloys. cubicity η Table 2. Volume fraction of reinforcing phase in single-crystal superalloy materials after different heat treatments Cubicity η, initial creep damage rate, and critical shear stress Table 3. Chemical composition of nickel-based single-crystal superalloy materials Table 3 shows that the relative error between the predicted and actual creep life values ​​of sample 1 (heat-treated 1) of the as-cast nickel-based single-crystal superalloy material is -3.3%, and the relative error between the predicted and actual creep life values ​​of sample 2 (heat-treated 2) is -2.3%. The absolute values ​​of both relative errors are less than 5%. This creep life prediction model can be used not only for the creep life of single-crystal alloys before and after heat treatment, but also for predictions based on damage parameters. The effects of heat treatment on the service performance of single-crystal turbine blades were evaluated with high accuracy.

[0042] By applying the technical solution of this invention, a creep life prediction model is constructed based on the creep curve parameters, creep damage equation, and creep constitutive equation of untreated as-cast nickel-based single-crystal superalloy materials and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes. By inputting the strengthening phase size, volume fraction, and cubicity of the heat-treated sample, the creep damage rate after heat treatment can be obtained, and thus the creep life can be calculated. The method of this invention can be used not only to predict the creep life of untreated as-cast nickel-based single-crystal superalloy materials but also to predict the creep life of heat-treated nickel-based single-crystal superalloy materials after service, providing a reference for the service performance evaluation of heat-treated single-crystal superalloy blades.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory, characterized in that, Includes the following steps: Step S1, Microstructure characteristics acquisition: Obtain microstructure images of untreated as-cast nickel-based single-crystal superalloy materials and nickel-based single-crystal superalloy materials after different heat treatment regimes, and extract the size, volume fraction and cubicity of the γ′ strengthening phase from them. Step S2, Macroscopic creep performance test: Through creep test, obtain the creep curves of untreated cast nickel-based single crystal superalloy material and nickel-based single crystal superalloy material after different heat treatment regimes, and extract information such as initial creep damage rate and creep life from them; Step S3, Critical Shear Stress Test: The critical shear stress of untreated cast nickel-based single-crystal superalloy materials and nickel-based single-crystal superalloy materials after different heat treatment regimes is obtained through tensile tests. Step S4, Construction of Crystal Plastic Creep Damage Model: Based on crystal plasticity theory, construct the creep constitutive equation and creep damage equation for coupled damage; among which, The creep constitutive equation is: ； The creep damage equation is as follows: ； In the formula, For the sliding system that is in operation, for Damage to slip system Damage rate of slip system For the shear stress of the slip system, For the creep shear strain rate of the slip system, These are the parameters for the second creep curve. The initial creep damage rate, The critical shear stress; A These are the parameters for the first creep curve. The parameters for the third creep curve are... These are the parameters for the fourth creep curve; Step S5, Derivation of the creep life prediction equation: Integrating the creep damage equation constructed in step S4, the explicit creep life prediction equation is derived, as follows: In the formula, For creep life, N is the number of slip surface opening directions in a slip system; Step S6: Establish the mapping relationship between the volume fraction of the strengthening phase, cubicity, critical shear stress, and initial creep damage rate of untreated cast nickel-based single crystal superalloy materials and nickel-based single crystal superalloy materials after different heat treatment regimes. Step S7: Obtain the mapping relationship between the volume fraction and cubicity of the strengthening phase and the creep life under different heat treatments, and predict the creep life of the heat-treated nickel-based single crystal superalloy material under different service conditions.

2. The method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory according to claim 1, characterized in that, The cubicity of the γ′ strengthening phase in step S1 is determined by the shape parameter ( The volume fraction of the γ′ strengthening phase is measured by polishing and etching the single crystal alloy, taking microscopic images using a scanning electron microscope, and then using image processing software to automatically calculate the volume fraction of the γ′ phase based on the difference in contrast between the γ′ phase and the γ phase.

3. The method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory according to claim 1, characterized in that, The critical shear stress test in step S3 specifically includes the following steps: Tensile tests were performed on the untreated as-cast nickel-based single-crystal superalloy material and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes to obtain tensile curves. Based on the tensile curve, the yield strength of the untreated as-cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy materials subjected to different heat treatment regimes are obtained. Based on the yield strength and crystal plasticity theory, the critical shear stress of the slip system is obtained. .

4. The method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory according to claim 1, characterized in that, The steps in step S4 for obtaining the initial creep damage rate and creep curve parameters of untreated cast nickel-based single-crystal superalloy materials and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes through creep testing are as follows: Creep tests were conducted on the aforementioned as-cast nickel-based single-crystal superalloy material without heat treatment and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes under different stresses to obtain creep curves; The initial creep damage rates of the untreated cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy materials subjected to different heat treatment regimes were obtained based on the creep curves. Based on the creep curves, creep curve parameters of the untreated cast nickel-based single-crystal superalloy material and nickel-based single-crystal superalloy materials subjected to different heat treatment regimes are obtained, including A. , , .

5. The method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory according to claim 1, characterized in that, The slip system shear stress of the nickel-based single-crystal superalloy material mentioned in step S4 It can be obtained through the following formula: ； ； σ is the orientation factor, and σ is the stress tensor in the crystal axis system (i.e., the stress state in the creep test). Let be the slip direction of the slip system. Let be the unit normal vector of the slip surface in the slip system.

6. The method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory according to claim 1, characterized in that, The step S4, which involves obtaining the creep life prediction equation for nickel-based single-crystal superalloys based on the creep damage equation, includes the following steps: Based on the creep damage equation described in step S4, the creep life prediction equation is obtained by integrating the damage rate from 0 to 1: 。 7. The method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory according to claim 1, characterized in that, The volume fraction of nickel-based single-crystal superalloy strengthening phase before and after the heat treatment in step S6 The mapping relationship between cubicity η, critical shear stress, and creep curve parameters is as follows: ； ； Wherein, the parameter x1 takes values ​​from 0 to 100, x2 takes values ​​from 0 to 200, y1 takes values ​​from 0 to 1, and y2 takes values ​​from 0 to 1, according to... ,and ,as well as , The relationship was obtained.

8. The method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory according to claim 1, characterized in that, The untreated as-cast nickel-based single-crystal superalloy material and the nickel-based single-crystal superalloy material treated with different heat treatment regimes have the same chemical composition, but differ in creep damage such as reinforcing phase size, volume fraction, cubicity, and initial creep damage rate.

9. The method for evaluating the creep performance of nickel-based single-crystal superalloy blades based on microstructure characteristics and crystal plasticity theory according to claim 1, characterized in that, The composition of the second-generation nickel-based single-crystal superalloy, by mass percentage, includes: Cr 4.0-6.0%, Co 8.0-10.0%, Mo 1.0-2.0%, W 6.0-8.0%, Ta 6.0-8.0%, Re 2.5-3.5%, Al 5.5-6.5%, Ti 0.5-1.5%, with the remainder being Ni and unavoidable impurities.

Images