阅读说明：本技术 变形高温合金涡轮盘服役温度和服役应力的实验评估方法 (Experimental evaluation method for service temperature and service stress of deformed high-temperature alloy turbine disk ) 是由 秦海龙 毕中南 于鸿垚 杜金辉 张继 安腾 迟海 史松宜 于 2020-12-30 设计创作，主要内容包括：本发明涉及高温合金涡轮盘技术领域,尤其是涉及一种变形高温合金涡轮盘服役温度和服役应力的实验评估方法。本发明通过建立一定时间下应力-温度-粗化程度-变体选择程度之间的对应关系,通过实验表征对涡轮盘的服役温度和服役应力进行评估。本发明的评估方法避免了数值模拟计算过程中边界条件不确定性的影响,且易操作,适合工程应用,具有广阔的应用前景。(The invention relates to the technical field of high-temperature alloy turbine disks, in particular to an experimental evaluation method for service temperature and service stress of a deformed high-temperature alloy turbine disk. According to the method, the service temperature and the service stress of the turbine disk are evaluated through experimental representation by establishing a corresponding relation among stress-temperature-coarsening degree-variant selection degree under a certain time. The evaluation method avoids the influence of uncertainty of boundary conditions in the numerical simulation calculation process, is easy to operate, is suitable for engineering application, and has wide application prospect.)

1. The experimental evaluation method for the service temperature and the service stress of the deformed high-temperature alloy turbine disk is characterized by comprising the following steps of:

(a) creep deformation or permanent interruption experiments under different temperatures, stresses and durations are carried out on alloy materials adopted by the turbine disc, a microstructure inside <001> oriented grains in the alloy after the experiments is subjected to three-dimensional representation, and the average long axis size of a gamma 'phase and the selection degree of the gamma' phase change body are counted to obtain the corresponding relations between different temperatures, stresses and durations and the average long axis size of the gamma 'phase and the selection degree of the gamma' phase change body;

(b) obtaining a three-dimensional representation result of a microstructure inside a <001> oriented crystal grain of a certain part of a turbine disc after T hours of actual service, and carrying out statistical calculation to obtain the average long axis size of a gamma 'phase and the selection degree of a gamma' phase change body of the certain part;

(c) comparing the average long axis size of the gamma ' phase of the certain part with the average long axis size of the gamma ' phase obtained after creep deformation or permanent interruption experiment at different temperatures for T hours in the step (a), and selecting the temperature corresponding to the average long axis size of the similar gamma ' phase as the service temperature evaluation result of the certain part;

(d) comparing the gamma ' phase change body selection degree of the certain part with the gamma ' phase change body selection degree of the step (a) after different stress creep or permanent interruption experiments under the condition of the service temperature with the duration of T hours, and selecting the stress corresponding to the similar gamma ' phase change body selection degree as the evaluation result of the service stress of the certain part.

2. The experimental evaluation method according to claim 1, wherein the alloy material used for the turbine disk is an alloy material in which a γ ″ phase is a main strengthening phase;

preferably, the alloy material comprises any one of GH4169 alloy, GH4169C alloy, GH4169G alloy, Inconel 625 alloy and Inconel 718 alloy.

3. The method for experimental evaluation according to claim 1, wherein in the creep or creep rupture test of step (a), the test temperature is 600-700 ℃;

preferably, in step (a), the creep or creep rupture test is carried out at test temperatures including 600 ℃, 650 ℃ and 700 ℃.

4. The experimental evaluation method of claim 1, wherein the creep or creep rupture test in step (a) has an experimental stress ranging from 0 to 700 MPa.

5. The experimental evaluation method of claim 1, wherein in the creep or permanent rupture test of step (a), the test time is 20-1500 h;

preferably, the experimental time period comprises 100h, 500h and 1500 h.

6. The experimental evaluation method of claim 1, wherein in the creep or creep rupture experiment of step (a), the experiment duration comprises the actual service duration of T hours.

7. The experimental evaluation method of claim 1, wherein the microstructure inside the <001> oriented grains is three-dimensionally characterized using a field emission electron scanning electron microscope and backscatter diffraction.

8. The experimental evaluation method of claim 1, wherein the degree of γ "phase transition selectivity Ω is calculated according to the following formula:

in the formula, alpha₁、α₂、α₃Are respectively three variants [001]]γ″、[010]γ' and [100]]Number fraction of gamma ", lambda₁、λ₂、λ₃Are respectively three variants [001]]γ″、[010]γ' and [100]]The average major axis dimension of γ ".

9. The experimental evaluation method of claim 1, wherein the turbine disk is made of an alloy material of GH4169 alloy.

10. The experimental evaluation method of claim 9, wherein the quantitative relationship between temperature and γ "phase mean major axis dimension λ is:

wherein λ is₀The average major axis dimension of the gamma' phase of the initial state tissue; q is the ratio of the average major axis dimension to the average minor axis dimension of the gamma' phase; gamma is interface energy; v_mIs the molar volume of the gamma' phase; c_eThe equilibrium concentration of solute atoms at an infinite radius of curvature; d₀Is the diffusion coefficient; qc is coarsening activation energy; r is a molar gas constant; t is the temperature; t is time.

Technical Field

The invention relates to the technical field of high-temperature alloy turbine disks, in particular to an experimental evaluation method for service temperature and service stress of a deformed high-temperature alloy turbine disk.

Background

An aircraft engine is a highly complex and precise thermal machine, and a turbine disc is one of the most important hot-end core components in the aircraft engine and needs to bear huge centrifugal force and thermal stress for a long time at a certain temperature. The temperature and the stress of each part of the turbine disk are different, namely the temperature field and the stress field are not uniform. The specific stress and temperature of the high-temperature alloy turbine disc are obtained, and the method has important guiding significance and industrial application value for guiding material selection and structural design of the turbine disc and determining an assessment node in the maintenance process.

At present, a numerical simulation calculation method based on boundary conditions and material thermal physical parameters is mostly adopted for the research of the temperature field and the stress field distribution of the turbine disk, and an experimental evaluation method based on a microstructure is not available.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The invention aims to provide an experimental evaluation method for service temperature and service stress of a deformed high-temperature alloy turbine disk.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the experimental evaluation method for the service temperature and the service stress of the deformed high-temperature alloy turbine disk comprises the following steps of:

(a) creep deformation or permanent interruption experiments under different temperatures, stresses and durations are carried out on alloy materials adopted by the turbine disc, a microstructure inside <001> oriented grains in the alloy after the experiments is subjected to three-dimensional representation, and the average long axis size of a gamma 'phase and the selection degree of the gamma' phase change body are counted to obtain the corresponding relations between different temperatures, stresses and durations and the average long axis size of the gamma 'phase and the selection degree of the gamma' phase change body;

(b) obtaining a three-dimensional representation result of a microstructure inside a <001> oriented crystal grain of a certain part of a turbine disc after T hours of actual service, and carrying out statistical calculation to obtain the average long axis size of a gamma 'phase and the selection degree of a gamma' phase change body of the certain part;

(c) comparing the average long axis size of the gamma ' phase of the certain part with the average long axis size of the gamma ' phase obtained after creep deformation or permanent interruption experiment at different temperatures for T hours in the step (a), and selecting the temperature corresponding to the average long axis size of the similar gamma ' phase as the service temperature evaluation result of the certain part;

(d) comparing the gamma ' phase change body selection degree of the certain part with the gamma ' phase change body selection degree of the step (a) after different stress creep or permanent interruption experiments under the condition of the service temperature with the duration of T hours, and selecting the stress corresponding to the similar gamma ' phase change body selection degree as the evaluation result of the service stress of the certain part.

The experimental evaluation method of the present invention, the gamma prime phase as the main strengthening phase of wrought superalloy, has three azimuthal variants ([001] gamma ", [010] gamma", and [100] gamma ") in the matrix. In the actual service process of the high-temperature alloy turbine disk, the initial gamma' phase change bodies with three orientation relations are selectively coarsened to form a variant selection structure. The temperature is the most main influence factor of the coarsening of the size of the gamma' phase, and a certain corresponding relation exists between the two factors. The temperature and the stress are main influence factors of the selection degree of the gamma' phase change body of the high-temperature alloy turbine disc, and a certain corresponding relation exists among the temperature and the stress. Therefore, the service temperature and the service stress of the turbine disk are evaluated through experimental representation by establishing the corresponding relation among the stress-temperature-coarsening degree-variant selection degree under a certain time.

In a specific embodiment of the invention, the alloy material adopted by the turbine disk is an alloy material with a gamma' phase as a main strengthening phase. Further, the alloy material includes any one of GH4169 alloy, GH4169C alloy, GH4169G alloy, Inconel 625 alloy, and Inconel 718 alloy.

In a specific embodiment of the invention, in the creep or permanent interruption experiment in the step (a), the experiment temperature is 600-700 ℃, the experiment stress range is 0-700 MPa, and the experiment time is 100-1500 h.

In a specific embodiment of the present invention, in the creep or permanent rupture test of step (a), the test temperature includes 600 ℃, 650 ℃ and 700 ℃, the test stress range is 0 to 700MPa, and the test time duration includes 100h, 500h and 1500 h.

In a particular embodiment of the invention, in said creep or permanent interruption test of step (a), the test duration comprises said actual length of service time T hours.

If the actual service time of the turbine disk to be tested is 500h, the experiment duration in the creep or permanent interruption experiment at least comprises 500 h.

In a specific embodiment of the present invention, the microstructure inside the <001> oriented grains is three-dimensionally characterized using field emission electron scanning electron microscopy (FE-SEM) and back-scattered diffraction (EBSD).

In a specific embodiment of the present invention, the degree of selectivity Ω of γ ″ phase transition is calculated according to the following formula:

in the formula, alpha₁、α₂、α₃Are respectively three variants [001]]γ″、[010]γ' and [100]]Number fraction of gamma ", lambda₁、λ₂、λ₃Are respectively three variants [001]]γ″、[010]γ' and [100]]The average major axis dimension of γ ". Wherein, the number fraction refers to the number ratio, and the unit of the average long axis size of the gamma' phase is nm.

The average long axis size lambda of the gamma' phase is three variants [001]]γ″、[010]γ' and [100]]The average major axis size of the whole of γ ″ can be calculated by: λ ═ α₁λ₁+α₂λ₂+α₃λ₃。

In the specific embodiment of the invention, the alloy material adopted by the turbine disk is GH4169 alloy. Further, the quantitative relationship between the temperature and the average long axis size λ of the γ ″ phase is as follows:

wherein λ is₀The average major axis dimension of the gamma' phase of the initial state tissue; q is the ratio of the average major axis dimension to the average minor axis dimension of the gamma' phase; gamma is interface energy; v_mIs the molar volume of the gamma' phase; c_eThe equilibrium concentration of solute atoms at an infinite radius of curvature; d₀Is the diffusion coefficient; qc is coarsening activation energy; r is a molar gas constant; t is the temperature; t is time.

Compared with the prior art, the invention has the beneficial effects that:

according to the method, the service temperature and stress of the key part of the turbine disk are evaluated by tissue characterization and by utilizing the quantitative relation between the temperature-coarsening size (average long axis size) and the temperature-stress-variant selection degree; the evaluation method avoids the influence of uncertainty of boundary conditions in the numerical simulation calculation process, is easy to operate, is suitable for engineering application, and has wide application prospect.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a gamma' modification selection image of GH4169 alloy within <001>, <011> and <111> orientation crystal grains under the action of thermal coupling of 650-500 MPa-1500 h;

FIG. 2 is a 3D image of the selection of <001>, <011> and <111> oriented intragranular gamma' variants of GH4169 alloy under the action of thermal coupling of 650-500 MPa-1500h according to an embodiment of the present invention; wherein (a) is a <001> oriented crystal grain, (b) is a <011> oriented crystal grain, and (c) is a <111> oriented crystal grain;

FIG. 3 shows the quantitative characterization results of the choice of the gamma' variants of GH4169 alloy after different temperature, stress and time thermal coupling simulations;

FIG. 4 shows the coarsening behavior of the gamma' phase under different temperature conditions of GH4169 alloy heat exposure provided by embodiments of the present invention;

FIG. 5 is a graph of the degree of gamma' modification selection omega as a function of stress and time at 600 deg.C for a GH4169 alloy provided by an embodiment of the present invention;

FIG. 6 is a graph of the degree of gamma' modification selection omega as a function of stress and time at 650 deg.C for a GH4169 alloy provided by an embodiment of the present invention;

FIG. 7 is a representation of the microstructure of a part of GH4169 alloy after 500h service according to an embodiment of the present invention.

Detailed Description

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The experimental evaluation method for the service temperature and the service stress of the deformed high-temperature alloy turbine disk comprises the following steps of:

(a) creep deformation or permanent interruption experiments under different temperatures, stresses and durations are carried out on alloy materials adopted by the turbine disc, a microstructure inside <001> oriented grains in the alloy after the experiments is subjected to three-dimensional representation, and the average long axis size of a gamma 'phase and the selection degree of the gamma' phase change body are counted to obtain the corresponding relations between different temperatures, stresses and durations and the average long axis size of the gamma 'phase and the selection degree of the gamma' phase change body;

(b) obtaining a three-dimensional representation result of a microstructure inside a <001> oriented crystal grain of a certain part of a turbine disc after T hours of actual service, and carrying out statistical calculation to obtain the average long axis size of a gamma 'phase and the selection degree of a gamma' phase change body of the certain part;

(c) comparing the average long axis size of the gamma ' phase of the certain part with the average long axis size of the gamma ' phase obtained after creep deformation or permanent interruption experiment at different temperatures for T hours in the step (a), and selecting the temperature corresponding to the average long axis size of the similar gamma ' phase as the service temperature evaluation result of the certain part;

(d) comparing the gamma ' phase change body selection degree of the certain part with the gamma ' phase change body selection degree of the step (a) after different stress creep or permanent interruption experiments under the condition of the service temperature with the duration of T hours, and selecting the stress corresponding to the similar gamma ' phase change body selection degree as the evaluation result of the service stress of the certain part.

Wherein, the specific operation of selecting the stress corresponding to the similar gamma' phase change body selection degree as the evaluation result of the service stress of the certain part in the step (d) comprises the following steps: (1) linearly interpolating experimental data (a graph of the change of the gamma' variant selection degree under the service temperature condition along with the stress and the time); (2) obtaining a stress value corresponding to the gamma' variant selection degree in linear interpolation; (3) the experimental stress value close to the stress value is the stress evaluation result.

The experimental evaluation method of the present invention, the gamma prime phase as the main strengthening phase of wrought superalloy, has three azimuthal variants ([001] gamma ", [010] gamma", and [100] gamma ") in the matrix. In the actual service process of the high-temperature alloy turbine disk, the initial gamma' phase change bodies with three orientation relations are selectively coarsened to form a variant selection structure. The temperature is the most main influence factor of the coarsening of the size of the gamma' phase, and a certain corresponding relation exists between the two factors. The temperature and the stress are main influence factors of the selection degree of the gamma' phase change body of the high-temperature alloy turbine disc, and a certain corresponding relation exists among the temperature and the stress. Therefore, the service temperature and the service stress of the turbine disk are evaluated through experimental representation by establishing the corresponding relation among the stress-temperature-coarsening degree-variant selection degree under a certain time.

The subject of the present invention is a turbine disk material whose strengthening phase is a gamma "phase (disk), equiaxed grains, and is untextured. The service temperature is evaluated by judging the coarsening of the size of the gamma 'phase, and on the basis, the service stress is evaluated by judging the degree of the crystallographic orientation distribution (variant selection) of the gamma' phase.

In a specific embodiment of the invention, the alloy material adopted by the turbine disk is an alloy material with a gamma' phase as a main strengthening phase. Further, the alloy material includes any one of GH4169 alloy, GH4169C alloy, GH4169G alloy, Inconel 625 alloy, and Inconel 718 alloy.

In a specific embodiment of the invention, in the creep or permanent interruption experiment in the step (a), the experiment temperature is 600-700 ℃, the experiment stress range is 0-700 MPa, and the experiment time is 20-1500 h.

In a specific embodiment of the present invention, in the creep or permanent rupture test of step (a), the test temperature includes 600 ℃, 650 ℃ and 700 ℃, the test stress range is 0 to 700MPa, and the test time duration includes 100h, 500h and 1500 h.

In a particular embodiment of the invention, in said creep or permanent interruption test of step (a), the test duration comprises said actual length of service time T hours.

In a specific embodiment of the present invention, the microstructure inside the <001> oriented grains is three-dimensionally characterized using field emission electron scanning electron microscopy (FE-SEM) and back-scattered diffraction (EBSD).

Specifically, a field emission electron scanning electron microscope (FE-SEM) and a back scattering diffraction (EBSD) technology are adopted for linkage; firstly, diamond-shaped marks are made on the surface of a metal sample in a nano indentation mode, an orientation distribution diagram is collected in an EBSD mode, then the position is adjusted to a secondary electron imaging mode (UED + GB) of an FE-SEM, and the microstructure in characteristic orientation grains (orientation of <001 >) is observed according to the positions of the diamond-shaped marks. The difference in orientation angle between the observed grains and the desired orientation cannot exceed 3 °.

In a specific embodiment of the present invention, the degree of selectivity Ω of γ ″ phase transition is calculated according to the following formula:

in the formula, alpha₁、α₂、α₃Are respectively three variants [001]]γ″、[010]γ' and [100]]Number fraction of gamma ", lambda₁、λ₂、λ₃Are respectively three variants [001]]γ″、[010]γ' and [100]]The average major axis dimension of γ ". Wherein, the number fraction refers to the number ratio, and the unit of the average major axis size is nm.

The average long axis size lambda of the gamma' phase is three variants [001]]γ″、[010]γ' and [100]]The average major axis size of the whole of γ ″ can be calculated by: λ ═ α₁λ₁+α₂λ₂+α₃λ₃。

In the specific embodiment of the invention, the material adopted by the turbine disk is GH4169 alloy. Further, the quantitative relationship between the temperature and the average long axis size λ of the γ ″ phase is as follows:

wherein λ is₀The average major axis dimension of the gamma' phase of the initial state tissue; q is the ratio of the average major axis dimension to the average minor axis dimension of the gamma' phase; gamma is interface energy; v_mIs the molar volume of the gamma' phase; c_eIs a curvature ofEquilibrium concentration of solute atoms at radius infinity; d₀Is the diffusion coefficient; qc is coarsening activation energy; r is a molar gas constant; t is the temperature; t is time. Measured and calculated, lambda₀The number is 25 nm; q is 0.48; the value of gamma is 95 x 10^-3J/m²；V_mThe value was 2.92X 10^-5m³/mol；C_eA value of 2560mol/m³；D₀The value was 8.8X 10^-5m²S; the value of Qc is 239 kJ/mol; the R value is 8.314472J/(mol.K). The average major axis dimension of the gamma "phase is linear with time t to the power of 1/3.

Example 1

The embodiment provides an experimental evaluation method for service temperature and service stress of a deformed superalloy turbine disk, which comprises the following steps:

(1) the GH4169 alloy for the turbine disk is processed into a standard creep or a durable sample, and thermal coupling effect experiments are carried out at the temperature of 600-700 ℃ (600 ℃, 650 ℃ and 700 ℃), at the pressure of 0-700 MPa and within the range of 20-1500 h (100h, 500h, 1500h and the like).

(2) The samples after the permanent interruption test are subjected to longitudinal section and cross section dissection, a field emission electron scanning microscope (FE-SEM) and a back scattering diffraction (EBSD) technology are adopted to carry out linkage characterization on the microstructure, and the characterization is shown in figure 1 by taking the conditions of 650-500 MPa-1500h as an example. The images of the cross-section and the longitudinal section are combined and spliced into a three-dimensional image, as shown in fig. 2.

(3) Under different thermo-thermal coupling conditions<001>Three variants of oriented grain interior [001]γ″、[010]γ' and [100]]Number fraction of gamma' (alpha)₁、α₂、α₃) Average major axis dimension (λ)₁、λ₂、λ₃) Statistics were performed and the degree of variant selection Ω in each state was calculated, and the results are shown in fig. 3. In that<001>Tensile stress in oriented grains [010]]γ' and [100]]The effect of the gamma "variant is equivalent, so that alpha₂＝α₃，λ₂＝λ₃。

(4) Establishing a temperature-related relationship with the average long axis of the gamma' phaseThe quantitative relationship is obtained by the following steps,

wherein λ is₀The average major axis dimension of the gamma' phase of the initial state tissue; q is the ratio of the average major axis dimension to the average minor axis dimension of the gamma' phase; gamma is interface energy; v_mIs the molar volume of the gamma' phase; c_eThe equilibrium concentration of solute atoms at an infinite radius of curvature; d₀Is the diffusion coefficient; qc is coarsening activation energy; r is a molar gas constant; t is the temperature; t is time. Lambda [ alpha ]₀The number is 25 nm; q is 0.48; the value of gamma is 95 x 10^-3J/m²；V_mThe value was 2.92X 10^-5m³/mol；C_eA value of 2560mol/m³；D₀The value was 8.8X 10^-5m²S; the value of Qc is 239 kJ/mol; the R value is 8.314472J/(mol.K). As shown in fig. 4 (the dotted line in the figure is the calculation result of the above quantitative relationship, and the point corresponds to the experimental data); establishing a quantitative relation between the stress-time-variant selection degree omega at a certain temperature according to the characteristics and the calculation result; the degree of selection omega for the gamma "variants as a function of stress and time is shown in figures 5 and 6, respectively, taking 600 c and 650 c as examples.

(5) The microstructure of a part of the GH4169 alloy turbine disk after T hours of service is subjected to three-dimensional characterization, and by taking the GH4169 alloy turbine disk after 500 hours of service as an example, the three-dimensional characterization result is shown in FIG. 7. The mean major axis size of the gamma "phase within this tissue was 61nm, with a degree of variant selection of 0.864. Comparing the average long axis size of the gamma ' phase of the part with the quantitative relation between the temperature and the average long axis size lambda of the gamma ' phase established in the step (4), wherein the average long axis size of the gamma ' phase of the part is equal to the average long axis size under the condition of 650-500 h (according to the condition that lambda is alpha ═ alpha₁λ₁+α₂λ₂+α₃λ₃Calculated) is close, so that the service temperature is estimated to be around 650 ℃; comparing the variant selection degree of the part with the quantitative relation in the relation graph shown in FIG. 6, and selecting the stress corresponding to the variant selection degree of 0.864 under the condition of 500h as the service response of the partAnd obtaining the service stress of the steel plate at about 500MPa according to the force evaluation result.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.