Characterization method for full-field mechanical property dispersibility of thermal barrier coating of turbine blade

Abstract

The invention discloses a characterization method for the full-field mechanical property dispersity of a thermal barrier coating of a turbine blade. The characterization method comprises the following steps: pretreating a thermal barrier coating sample of the turbine blade; obtaining mechanical property data of the turbine blade thermal barrier coating sample, wherein the mechanical property data comprises thermal barrier coating section porosity, thermal barrier coating thickness, thermal barrier coating section density, thermal barrier coating elasticity modulus and thermal barrier coating hardness; and importing the mechanical property data into Matlab, and establishing a three-dimensional model of the thermal barrier coating of the turbine blade based on a two-dimensional interpolation method or a linear interpolation method so as to represent the overall mechanical property of the thermal barrier coating of the turbine blade and the mechanical property of the local region position. According to the method, a three-dimensional model of the turbine blade thermal barrier coating is established through Matlab, and a two-dimensional interpolation or linear interpolation method is used in combination with contour lines, so that the mechanical property dispersity of the whole or local area of the turbine blade thermal barrier coating can be well represented.

Description

Technical Field

[0001] The invention belongs to the technical field of material micro-nano processing and characterization, and specifically relates to a method for characterizing the dispersion of full-field mechanical properties of a thermal barrier coating on a turbine blade. Background Art

[0002] Thermal barrier coatings (TBCs) are a type of ceramic coating that has excellent resistance to high-temperature oxidation and very low thermal conductivity. It is deposited on the surface of high-temperature resistant metals or superalloys through a bonding layer, which can effectively reduce the service temperature of the protected substrate, reduce its thermal shock load, reduce the demand for cooling air, and improve the thermal efficiency of the device. Therefore, it is widely used in aerospace, chemical, metallurgy, energy and other fields.

[0003] The life of thermal barrier coatings has always been a key research topic in thermal barrier coating research. Since the mechanical properties and service environment of thermal barrier coatings on turbine blades are dispersed, their life is also dispersed, that is, the life of certain positions of the blade is the shortcoming of the blade life. Existing research also lacks reliable characterization of the dispersion of the mechanical properties of thermal barrier coatings for turbine blades throughout the field.

[0004] In the prior art, Weibull distribution is used to characterize the dispersion of the full-field mechanical properties of turbine blade thermal barrier coatings. The Weibull cumulative distribution probability is:

[0005] P i =1-[-(X i X 0 ) m ]

[0006] Among them, P i represents the cumulative distribution probability; i represents the serial number; X 0 represents the eigenvalue of a certain performance Weibull distribution; m represents the Weibull modulus. The larger the m, the smaller the dispersion of the test results; X i Represents the i-th value from small to large.

[0007] The Weibull cumulative distribution probability can be rewritten as:

[0008] ln ln[1 / (1-P i )]=m ln X i -m ln X 0

[0009] ln ln[1 / (1-P i )] is the y-axis, ln H i is the x-axis, -m ln H 0The formula is a linear function expression, and the slope of the function expression is the modulus m of the Weibull distribution. Therefore, the size parameter X of the linearly fitted Weibull distribution can be obtained by using the measured X value. 0 , arrange the N values ​​measured in the experiment in order from small to large, and the probability that its value is not higher than the i-th value (X)i is P i , P i for:

[0010] P i =i / (N+1)

[0011] Where: N is the capacity of the sample. Combining the above equations, we can get the equation:

[0012]

[0013] Through linear regression analysis, the least squares method is used to obtain m and X 0 .

[0014] The above-mentioned defects of Weibull distribution are: it can only analyze and present the overall dispersion of mechanical properties of thermal barrier coatings on turbine blades, but cannot analyze and present the dispersion and change trend of mechanical properties of a certain local area at different positions on the thermal barrier coating. Most importantly, the dispersion of mechanical properties of thermal barrier coatings obtained by using Weibull distribution is independent of its size, that is, the size of thermal barrier coatings cannot be considered when characterizing the dispersion of mechanical properties of thermal barrier coatings. This leads to the conclusion that the dispersion of mechanical properties is basically the same when using Weibull distribution to analyze the dispersion of mechanical properties of thermal barrier coatings on turbine blades of different sizes. But in fact, the change rate of mechanical properties of thermal barrier coatings on larger turbine blades is smaller, that is, when taking the same size area for Weibull distribution analysis, it will be concluded that the dispersion of mechanical properties of thermal barrier coatings on larger turbine blades is smaller, which brings great inconvenience to the characterization of dispersion of thermal barrier coatings.

[0015] In summary, the existing technology for characterizing the dispersion of the full-field mechanical properties of thermal barrier coatings for turbine blades has the following problems: it is impossible to analyze the dispersion and change trend of the mechanical properties of a local area at different positions on the thermal barrier coating; the performance dispersion obtained by characterization is not related to the size of the sample. Summary of the invention

[0016] In view of the problems that the characterization of the dispersion of the full-field mechanical properties of the thermal barrier coating of a turbine blade in the prior art cannot analyze the dispersion and changing trend of the mechanical properties of a local area at different positions on the thermal barrier coating, and the performance dispersion obtained by characterization is not related to the size of the sample, the purpose of the present invention is to provide a method for characterizing the dispersion of the full-field mechanical properties of the thermal barrier coating of a turbine blade. A three-dimensional model of the thermal barrier coating of a turbine blade is established by Matlab, and two-dimensional interpolation or linear interpolation is used, combined with contour lines, so that the dispersion of the mechanical properties of the thermal barrier coating of the turbine blade as a whole or in a local area can be well characterized.

[0017] The purpose of the present invention is achieved through the following technical solutions:

[0018] A method for characterizing the dispersion of full-field mechanical properties of a thermal barrier coating of a turbine blade comprises the following steps:

[0019] S1. Pre-treatment of turbine blade thermal barrier coating samples, including:

[0020] S11. Cutting the thermal barrier coating of the turbine blade to obtain a plurality of cross-sectional samples;

[0021] S12. The cross-sectional sample is mounted to obtain a cross-sectional sample after curing;

[0022] S13. Grinding and polishing the cross-section sample after curing;

[0023] S14. The cross-section sample after grinding and polishing is ultrasonically cleaned and dried;

[0024] S2. Obtaining mechanical property data of the thermal barrier coating sample of the turbine blade, wherein the mechanical property data includes: thermal barrier coating cross-sectional porosity, thermal barrier coating thickness, thermal barrier coating cross-sectional density, thermal barrier coating elastic modulus and thermal barrier coating hardness;

[0025] The elastic modulus and hardness of the thermal barrier coating of the turbine blade thermal barrier coating sample are obtained according to the following formula:

[0026] M=M 0 exp(-BP) (1)

[0027] 1=P+D (2)

[0028] M=M 0 (e B ) D-1 (3)

[0029] E eq =E 0 (e B ) D-1 (4)

[0030] H=H 0 (e B ) D-1 (5)

[0031] Among them, M and M 0 They represent elastic modulus and hardness respectively, P represents porosity, D represents density, M 0 and B are both constants;

[0032] S3. Importing the mechanical property data obtained in the above step into Matlab, and establishing a three-dimensional model of the thermal barrier coating of the turbine blade based on a two-dimensional interpolation method or a linear interpolation method to characterize the overall mechanical properties of the thermal barrier coating of the turbine blade and the mechanical properties of the local area, including:

[0033] Importing the two-dimensional position coordinates of the thermal barrier coating of the turbine blade into Matalab;

[0034] Selecting n points on the thermal barrier coating of the turbine blade and assigning positions to the coordinates of the n points;

[0035] Sort the n points and import the mechanical property data;

[0036] Use two-dimensional interpolation or linear interpolation to interpolate and divide the Z-axis range;

[0037] A three-dimensional surface diagram of the thermal barrier coating of the turbine blade is constructed according to the two-dimensional position coordinates and the Z-axis range to obtain a three-dimensional model.

[0038] In the present invention:

[0039] Furthermore, step S11 is to fix the prepared turbine blade thermal barrier coating sample on a linear cutting machine to cut a plurality of cross-section samples.

[0040] Furthermore, step S12 is to mount the cross-section sample with epoxy resin glue to obtain a cured cross-section sample, specifically, placing the cross-section sample into the mold with the cross section facing downward; then mixing epoxy resin A glue and B glue in a weight ratio of 2:1 and stirring evenly, and pouring them into the mold; finally, placing the mold in a 60°C insulation box for 50 minutes to allow the mounting glue to solidify.

[0041] Furthermore, step S13 is to fix the solidified cross-sectional sample on a grinding machine, and grind and polish the cross-sectional sample. Specifically, 180 mesh, 300 mesh, 600 mesh, and 1200 mesh water-abrasive sandpaper are used to grind the cross-sectional sample in sequence for 5 minutes; then, with the same force, 7 μm, 2.5 μm, 1 μm, and 0.5 μm diamond polishing powder are used to polish the cross-sectional sample in sequence for 5 minutes, until the surface of the cross-sectional sample is smooth and free of obvious scratches.

[0042] Furthermore, step S14 is to put the cross-section sample obtained after grinding and polishing into a beaker containing alcohol, and put the beaker into an ultrasonic cleaner to clean the cross-section sample for 5 minutes. After cleaning, use a hair dryer to dry the surface.

[0043] Furthermore, the step S3 of importing the two-dimensional position coordinates of the turbine blade thermal barrier coating in Matalab includes: when using the two-dimensional interpolation method, the imported two-dimensional position coordinates start from the second one of the original coordinates and use it as the last position coordinate, and the remaining position coordinates become the n-1th one in turn; or when using the linear interpolation, the imported two-dimensional position coordinates correspond to the original number of the original coordinates.

[0044] Furthermore, the step S3 of selecting n points on the thermal barrier coating of the turbine blade and assigning positions to the coordinates of the n points includes: when using the two-dimensional interpolation method, the first point is assigned twice, as position 1 and position n+1 respectively, and the remaining points are assigned once; when using the linear interpolation method, the coordinates of the n points are assigned in turn, for a total of n times.

[0045] Furthermore, the step S3 of constructing a three-dimensional surface map of the thermal barrier coating of the turbine blade according to the two-dimensional position coordinates and the Z-axis range to obtain a three-dimensional model includes: constructing a surface map in Matlab according to the two-dimensional position coordinates and the Z-axis range; turning off the grid lines in Matlab and setting the background to white; importing a color table and drawing contour lines, and using the color changes and the width of the contour lines to characterize the mechanical properties of the thermal barrier coating of the turbine blade.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] 1. The method for characterizing the dispersion of the full-field mechanical properties of the thermal barrier coating of a turbine blade described in the present invention uses Matlab to establish a three-dimensional model of the thermal barrier coating of the turbine blade, and uses a two-dimensional interpolation method or a linear interpolation method to well characterize the dispersion of the mechanical properties of the thermal barrier coating of the turbine blade as a whole or in each local area.

[0048] 2. The method for characterizing the dispersion of the mechanical properties of the thermal barrier coating of a turbine blade in the whole field of the present invention is combined with contour lines, because the width of the contour lines characterizes the rate of change of the performance, that is, the wider the contour line size, the lower the rate of change of the data at this position; at the same time, by analyzing the density of the contour lines, the degree of dispersion of the mechanical properties of each position on the thermal barrier coating of the turbine blade can be clearly known;

[0049] The dispersion of mechanical properties of thermal barrier coatings on turbine blades can be correlated with their size. Even if blades of different sizes have the same overall dispersion, the mechanical dispersion of the same area can be analyzed. Similarly, even if blades of different sizes have the same mechanical dispersion of the same area, the overall dispersion can be analyzed based on the model and contour lines.

[0050] 3. The method for characterizing the dispersion of the full-field mechanical properties of the thermal barrier coating of a turbine blade described in the present invention enables the dispersion of the full-field mechanical properties of the thermal barrier coating of the turbine blade to be clearly and distinctly characterized from the whole to the part, and the distribution of the mechanical properties of the thermal barrier coating of the turbine blade and the change of the mechanical properties with the change of position can be clearly seen;

[0051] The dispersion and change trend of the mechanical properties of a certain local area at different positions on the thermal barrier coating can be clearly seen;

[0052] The characterized performance scatter is related to the sample size and can be used to analyze TBC blades of different sizes and compare their scatter. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A diagram of blade profile measurement points in an embodiment of the present invention;

[0054] Figure 2 A graph showing the porosity, thickness, and density of a cross-section of a thermal barrier coating in an embodiment of the present invention;

[0055] Figure 3 A graph showing the Young's modulus data fitting of the thermal barrier coating in an embodiment of the present invention;

[0056] Figure 4 A diagram showing the fitting of the hardness value data of the thermal barrier coating in the embodiment of the present invention;

[0057] Figure 5 Graph showing a three-dimensional model of the dispersion of mechanical properties of thermal barrier coatings in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0059] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0060] Figure 1 is a diagram of the blade profile measurement points.

[0061] Example:

[0062] A method for characterizing the dispersion of full-field mechanical properties of a thermal barrier coating of a turbine blade comprises the following steps:

[0063] Step S1: pre-treating a turbine blade thermal barrier coating sample;

[0064] Step S2: obtaining the thermal barrier coating cross-sectional porosity, thermal barrier coating thickness, thermal barrier coating cross-sectional density, thermal barrier coating elastic modulus, and thermal barrier coating hardness of the turbine blade thermal barrier coating sample;

[0065] Step S3: using Matlab to establish a three-dimensional model of the thermal barrier coating of the turbine blade to characterize the overall mechanical properties and the mechanical properties of the local area of ​​the thermal barrier coating of the turbine blade;

[0066] Wherein, step S1 comprises:

[0067] Step S11: fixing the prepared turbine blade thermal barrier coating sample on a linear cutting machine, and cutting a plurality of cross-section samples;

[0068] Step S12: Mounting the cross-section sample with epoxy resin glue to obtain a cured cross-section sample;

[0069] Specifically, place the cross-section sample with the cross section facing downward into the mold; then mix epoxy resin A glue and B glue in a weight ratio of 2:1 and stir evenly, then pour into the mold; finally, place the mold in a 60°C incubator for 50 minutes to allow the mounting glue to solidify;

[0070] Step S13: fixing the solidified cross-section sample on a grinding machine, and grinding and polishing the cross-section of the cross-section sample;

[0071] Specifically, the cross-sectional sample was polished with 180 mesh, 300 mesh, 600 mesh, and 1200 mesh water-abrasive sandpaper in sequence for 5 minutes; then, with the same force, the cross-sectional sample was polished with 7 μm, 2.5 μm, 1 μm, and 0.5 μm diamond polishing powder in sequence for 5 minutes until the surface of the cross-sectional sample was smooth and free of obvious scratches;

[0072] Step S14: Put the cross-section sample obtained after grinding and polishing into a beaker containing alcohol, and put the beaker into an ultrasonic cleaner to clean the cross-section sample for 5 minutes. After cleaning, use a hair dryer to dry the surface;

[0073] Step S2 includes:

[0074] Step S21: acquiring the two-dimensional coordinates of the cross section of the pre-processed cross-section sample by means of a scanner;

[0075] Step S22: measuring the cross-sectional porosity and thickness of the thermal barrier coating of the cross-sectional sample;

[0076] Specifically, when measuring the thickness of the thermal barrier coating of the cross-sectional sample, the thickness of the thermal barrier coating and the thickness of the bonding layer at multiple points of the cross-sectional sample are directly measured using a SEM (scanning electron microscope).

[0077] When measuring the cross-sectional porosity of the thermal barrier coating at multiple points of the cross-sectional sample, the cross-sectional morphology of the thermal barrier coating of the cross-sectional sample is observed by SEM combined with a BSE (Electronback scattered diffraction) detector, and an image characterizing the chemical composition by grayscale changes is obtained; then the obtained digital microscopic image is analyzed on the Matrox-II program, and different values ​​are set according to different grayscales on the microscopic image of the thermal barrier coating, and the black area (i.e., the pore area) existing in the thermal barrier coating is calibrated according to different numerical values, and the porosity of the thermal barrier coating is calculated according to the proportion of the black area in the entire thermal barrier coating structure;

[0078] Figure 2 It is a graph of the porosity, thickness, and density of the cross section of the thermal barrier coating;

[0079] Step S23: determining the elastic modulus and hardness of the thermal barrier coating;

[0080] Specifically, firstly, the Vickers indenter is calibrated, the pretreated cross-section sample is fixed on the sample stage, a smooth and flat area is selected on the surface of the cross-section sample, and then the Vickers indenter is used to perform an indentation test on the pretreated cross-section sample to obtain the experimental data required for calculating the elastic modulus and hardness of the thermal barrier coating;

[0081] The experimental data required to calculate the elastic modulus and hardness of thermal barrier coatings include: the area of ​​the indenter pressed on the cross-section sample during the indentation test, the load increment, the increment of the indentation depth within the range of 60–95% of the maximum load during unloading after loading, the Poisson's ratio of the coating, the Young's modulus of the indenter, the Poisson's ratio of the indenter, the maximum load, and the depth value corresponding to the maximum load;

[0082] When conducting the indentation test, in order to ensure the accuracy of the data, six different positions were selected on the cross section for the indentation test, and five indentation points were selected at each position. The spacing between each indentation point should be appropriate (the spacing between each indentation point should be at least 5 times the indentation size) to avoid mutual influence; the indentation process includes: loading, holding and unloading. The whole indentation process adopts a constant load rate, the loading and unloading rates are 10mN / s, and the peak load is set to 8mN; the loading, holding and unloading times are 10s, 5s, and 10s respectively;

[0083] Finally, the experimental data was substituted into the following formula for calculation to obtain the elastic modulus and hardness of the thermal barrier coating;

[0084]

[0085] In the above formula, A is the indenter area, dP is the load increment, and dh is the increment of the indentation depth in the range of 60–95% of the maximum load during unloading after loading;

[0086]

[0087] In the above formula, E c is the Young's modulus of the coating, v c is the Poisson's ratio of the coating, E i and v i are Young’s modulus and Poisson’s ratio of the indenter, respectively;

[0088]

[0089] In the above formula, P max is the maximum load, h is the depth corresponding to the maximum load;

[0090] The elastic modulus and hardness of the thermal barrier coating can be calculated according to the above three formulas;

[0091] Since the columnar crystals will be destroyed after the cross-section sample is polished, directly using the nanoindentation method to measure the elastic modulus and hardness of the thermal barrier coating will lead to inaccurate experimental results, and the error range of the values ​​measured multiple times is too large; therefore, the present invention uses the following method to determine the elastic modulus and hardness of the thermal barrier coating:

[0092] The expressions for the elastic modulus and hardness of the thermal barrier coating are as follows:

[0093] M = M 0 exp(-BP) (1)

[0094] In Equation (1), M and M 0 represent the Young's modulus and hardness of the dense material and the porous material respectively, and P represents the porosity;

[0095] Also according to:

[0096] 1 = P + D (2)

[0097] D represents the relative density, so combining Equation (1) and Equation (2) can be written as:

[0098] M = M 0 (e B ) D-1 (3)

[0099] In Equation (3), e B > 1, 0 < D < 1, and the only factors that can affect the values of B and M 0 are the composition and phase structure of the material. In the ideal case, both the APS coating and the EB - PVD YSZ coating are in the t' phase. Therefore, M 0 and B in the above Equation (3) are both constants; the value of M 0 can be determined by the exhaustive method, that is, through multi - point fitting by nano - indentation method, the M 0 and e B in the selected coating can be determined; Therefore, we only need to measure the value of the relative density D in the above Equation (3) to obtain the Young's modulus and hardness at the corresponding point;

[0100] The Young's modulus and hardness are written as:

[0101] E eq = E 0 (e B ) D-1 (4)

[0102] H = H 0 (e B ) D-1 (5)

[0103] Determination of E 0 and H 0 : Using the data obtained in the experiment, the Young's modulus values and hardness values are respectively fitted;

[0104] Specifically, for the five - point fitting of the Young's modulus, the determination coefficient is 0.9842, E 0 = 251.1, e B=5.261; hardness five-point fitting, determination coefficient 0.9688, H 0 =10.71, e B =5.344; the density D is obtained by combining the porosity measured in step S22 with formula (3);

[0105] Figure 3 This is a graph of the Young's modulus data fit of thermal barrier coatings;

[0106] Step S3 includes:

[0107] Step S31: importing the two-dimensional position coordinates of the thermal barrier coating of the turbine blade into Matalab;

[0108] Step S32: assigning positions to the coordinates of the n points measured in step S2;

[0109] Step S33: sorting the n measured points and importing mechanical property data;

[0110] Step S34: using a two-dimensional interpolation method or a linear interpolation method to perform interpolation and divide the Z-axis range;

[0111] Step S35: construct a three-dimensional surface image of the thermal barrier coating of the turbine blade according to the two-dimensional position coordinates and the Z-axis range, and adjust the format, import the color table, set the viewing angle, and obtain a complete three-dimensional model;

[0112] Specifically, in step S31, if the subsequent step S34 uses the two-dimensional interpolation method, the imported position coordinates start from the second one of the original coordinates and are used as the last position coordinate, and the remaining position coordinates become the n-1th one in sequence;

[0113] If the subsequent step S34 uses linear interpolation, the imported position coordinates correspond to the original number of original coordinates;

[0114] In step S32, if the subsequent step S34 uses two-dimensional interpolation, in order to make the surfaces coincide, the first point is assigned twice, as position 1 and position n+1 respectively, so a total of n+1 times are assigned;

[0115] If the subsequent step S34 uses linear interpolation, the coordinates of the n points are assigned values ​​in sequence, for a total of n times;

[0116] In step S33, sorting all measurement points on the sample cross section includes the following steps:

[0117] Specifically, when using linear interpolation:

[0118] kx = zeros(7,1);

[0119] for i=1:40

[0120] if XX(i,1)==x1(1)

[0121] kx(1)=i;

[0122] elseif XX(i,1)==x1(2)

[0123] kx(2)=i;

[0124] elseif XX(i,1)==x1(3)

[0125] kx(3)=i;

[0126] elseif XX(i,1)==x1(4)

[0127] kx(4)=i;

[0128] elseif XX(i,1)==x1(5)

[0129] kx(5)=i;

[0130] elseif XX(i,1)==x1(6)

[0131] kx(6)=i;

[0132] end

[0133] end

[0134] for i=41:79

[0135] if XX(i,1)==x1(2)

[0136] kx(2)=i;

[0137] elseif XX(i,1)==x1(3)

[0138] kx(3)=i;

[0139] elseif XX(i,1)==x1(4)

[0140] kx(4)=i;

[0141] elseif XX(i,1)==x1(5)

[0142] kx(5)=i;

[0143] elseif XX(i,1)==x1(6)

[0144] kx(6)=i;

[0145] elseif XX(i,1) == x1(7)

[0146] kx(7) = i;

[0147] end

[0148] end

[0149] When using two-dimensional interpolation: kx = zeros(6,1);

[0150] for i = 1:79

[0151] if XX(i,1) == x1(1)

[0152] kx(1) = i;

[0153] elseif XX(i,1) == x1(2)

[0154] kx(2) = i;

[0155] elseif XX(i,1) == x1(3)

[0156] kx(3) = i;

[0157] elseif XX(i,1) == x1(4)

[0158] kx(4) = i;

[0159] elseif XX(i,1) == x1(5)

[0160] kx(5) = i;

[0161] elseif XX(i,1) == x1(6)

[0162] kx(6) = i;

[0163] end

[0164] end

[0165] ky = zeros(6,1);

[0166] for i = 1:79

[0167] if XX(i,2) == y1(1)

[0168] ky(1) = i;

[0169] elseif XX(i,2) == y1(2)

[0170] ky(2) = i;

[0171] elseif XX(i,2)==y1(3)

[0172] ky(3)=i;

[0173] elseif XX(i,2)==y1(4)

[0174] ky(4)=i;

[0175] elseif XX(i,2)==y1(5)

[0176] ky(5)=i;

[0177] elseif XX(i,2)==y1(6)

[0178] ky(6)=i;

[0179] end

[0180] end

[0181] In step S34, interpolation is performed on a circle of the sample cross section and between cross sections according to the sequence number;

[0182] Two-dimensional interpolation method (cubic spline interpolation method, bilinear interpolation method): replace the x-axis and y-axis coordinates of the points on the surface with arranged serial numbers, so that the entire surface is flattened, and then two-dimensional interpolation is performed, and finally it is closed and restored;

[0183] Linear interpolation: first perform linear interpolation on the section, then perform linear interpolation between each section;

[0184] The divided Z-axis range includes: setting the height on the Z-axis to 20-70 and dividing it into 79 parts;

[0185] In step S35, a surface graph is first constructed in Matlab according to the two-dimensional position coordinates and the Z-axis range, and then the grid line display is turned off and the background is set to white; finally, a color table is imported to use the color change to characterize the change in mechanical properties of the blade thermal barrier coating;

[0186] Figure 4 This is a graph of the thermal barrier coating hardness value data fitting;

[0187] The mechanical properties here refer to the density of the blade thermal barrier coating;

[0188] When using color changes to characterize the mechanical properties of blade thermal barrier coatings, contour lines are drawn and the width of the contour lines is used to characterize the rate of change of the mechanical properties; the wider the contour line size, the lower the rate of change of the data at that location;

[0189] Specifically, the entire data is divided into 256 colors for representation, and the color scale is divided into 17 parts by black lines; the black line is the contour line, and its width represents the data range of ±(maximum value-minimum value) / 512, which means that the wider the contour line size, the lower the data change rate at that position; at the same time, we can clearly and intuitively know the degree of dispersion of mechanical properties at each position by analyzing the density of the contour lines. The greater the density of the contour lines, the greater the dispersion;

[0190] At the same time, make format adjustments. Specifically, change the color scale to match the line and set the font size; adjust the window size; set the XY axis coordinate range; set the axis scale;

[0191] The viewing angle is set. In the embodiment of the present invention, the viewing angle is set to appear from 135° to 30°, and finally a complete three-dimensional model is obtained.

[0192] Figure 5 A diagram of the three-dimensional model of the dispersion of mechanical properties of thermal barrier coatings.

[0193] Results and Discussion:

[0194] The present invention aims to protect a method for characterizing the dispersion of the full-field mechanical properties of a thermal barrier coating of a turbine blade, including pre-treating a thermal barrier coating sample of a turbine blade; obtaining mechanical property data of the thermal barrier coating sample of a turbine blade, the mechanical property data including: the cross-sectional porosity of the thermal barrier coating, the thickness of the thermal barrier coating, the cross-sectional density of the thermal barrier coating, the elastic modulus of the thermal barrier coating, and the hardness of the thermal barrier coating; importing the mechanical property data into Matlab, and establishing a three-dimensional model of the thermal barrier coating of the turbine blade based on a two-dimensional interpolation method or a linear interpolation method, so as to characterize the overall mechanical properties of the thermal barrier coating of the turbine blade and the mechanical properties of the local area. By establishing a three-dimensional model of the thermal barrier coating of the turbine blade through Matlab, and using a two-dimensional interpolation method or a linear interpolation method, combined with contour lines, the dispersion of the mechanical properties of the thermal barrier coating of the turbine blade as a whole or in a local area can be well characterized.

[0195] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A method for characterizing the dispersion of the full-field mechanical properties of thermal barrier coatings for turbine blades, characterized in that: The following steps are involved: S1. Pre-treatment of turbine blade thermal barrier coating samples, including: S11. Cutting the thermal barrier coating of the turbine blade to obtain a plurality of cross-sectional samples; S12. The cross-sectional sample is mounted to obtain a cross-sectional sample after curing; S13. Grinding and polishing the cross-section sample after curing; S14. The cross-section sample after grinding and polishing is ultrasonically cleaned and dried; S2. Obtaining mechanical property data of the thermal barrier coating sample of the turbine blade, wherein the mechanical property data includes: thermal barrier coating cross-sectional porosity, thermal barrier coating thickness, thermal barrier coating cross-sectional density, thermal barrier coating elastic modulus and thermal barrier coating hardness; The elastic modulus and hardness of the thermal barrier coating of the turbine blade thermal barrier coating sample are obtained according to the following formula: M=M0exp(-BP) (1) 1=P+D (2) M=M0(and B ) D-1 (3) E eq =E0(e B ) D-1 (4) <h2 style=";text-align:left;direction:ltr">H=H0(e<h2 style=";text-align:left;direction:ltr"> B <h2 style=";text-align:left;direction:ltr"> )<h2 style=";text-align:left;direction:ltr"> D-1 <h2 style=";text-align:left;direction:ltr"> (5) Among them, M and M0 represent elastic modulus and hardness respectively, P represents porosity, D represents density, and M0 and B are both constants; S3. Importing the mechanical property data obtained in the above step into Matlab, and establishing a three-dimensional model of the thermal barrier coating of the turbine blade based on a two-dimensional interpolation method or a linear interpolation method to characterize the overall mechanical properties of the thermal barrier coating of the turbine blade and the mechanical properties of the local area, including: Importing the two-dimensional position coordinates of the thermal barrier coating of the turbine blade into Matalab; Selecting n points on the thermal barrier coating of the turbine blade and assigning positions to the coordinates of the n points; Sort the n points and import the mechanical property data; Use two-dimensional interpolation or linear interpolation to interpolate and divide the Z-axis range; A three-dimensional surface diagram of the thermal barrier coating of the turbine blade is constructed according to the two-dimensional position coordinates and the Z-axis range to obtain a three-dimensional model.

2. The method for characterizing the dispersion of the full-field mechanical properties of a thermal barrier coating for a turbine blade according to claim 1, characterized in that: Step S11 is to fix the prepared turbine blade thermal barrier coating sample on a linear cutting machine and cut a plurality of cross-section samples.

3. The method for characterizing the dispersion of the full-field mechanical properties of a thermal barrier coating for a turbine blade according to claim 1, characterized in that: Step S12 is to use epoxy resin glue to mount the cross-section sample to obtain a cured cross-section sample. Specifically, the cross-section sample is placed into the mold with the cross section facing downward; then epoxy resin A glue and B glue are mixed and stirred evenly in a weight ratio of 2:1, and then poured into the mold; finally, the mold is placed in a 60°C insulation box for 50 minutes to allow the mounting glue to solidify.

4. The method for characterizing the dispersion of the full-field mechanical properties of a thermal barrier coating for a turbine blade according to claim 1, characterized in that: Step S13 is to fix the solidified cross-section sample on the grinding machine, and grind and polish the cross-section of the cross-section sample. Specifically, use 180 mesh, 300 mesh, 600 mesh, and 1200 mesh water-abrasive sandpaper to grind the cross-section sample in turn, and the grinding time is 5 minutes; then use the same force to polish the cross-section sample in turn using 7μm, 2.5μm, 1μm, and 0.5μm diamond polishing powder, and the polishing time is 5 minutes, until the surface of the cross-section sample is smooth and there are no obvious scratches.

5. The method for characterizing the dispersion of the full-field mechanical properties of a thermal barrier coating for a turbine blade according to claim 1, characterized in that: Step S14 is to put the cross-section sample obtained after grinding and polishing into a beaker containing alcohol, and put the beaker into an ultrasonic cleaner to clean the cross-section sample for 5 minutes. After cleaning, use a hair dryer to dry the surface.

6. The method for characterizing the dispersion of the full-field mechanical properties of a thermal barrier coating for a turbine blade according to claim 1, characterized in that: The step S3 of importing the two-dimensional position coordinates of the turbine blade thermal barrier coating in Matalab includes: when using the two-dimensional interpolation method, the imported two-dimensional position coordinates start from the second one of the original coordinates and use it as the last position coordinate, and the remaining position coordinates become the n-1th one in turn; or when using the linear interpolation, the imported two-dimensional position coordinates correspond to the original number of the original coordinates.

7. The method for characterizing the dispersion of the full-field mechanical properties of a thermal barrier coating for a turbine blade according to claim 1, characterized in that: The step S3 of selecting n points on the thermal barrier coating of the turbine blade and assigning positions to the coordinates of the n points includes: when using the two-dimensional interpolation method, the first point is assigned twice, as position 1 and position n+1 respectively, and the remaining points are assigned once; when using the linear interpolation method, the coordinates of the n points are assigned in sequence, for a total of n times.

8. The method for characterizing the dispersion of the full-field mechanical properties of a thermal barrier coating for a turbine blade according to claim 1, characterized in that: The step S3 of constructing a three-dimensional surface map of the thermal barrier coating of the turbine blade according to the two-dimensional position coordinates and the Z-axis range to obtain a three-dimensional model includes: constructing a surface map in Matlab according to the two-dimensional position coordinates and the Z-axis range; turning off the grid lines in Matlab and setting the background to white; importing a color table and drawing contour lines, and using color changes and contour line widths to characterize the mechanical properties of the thermal barrier coating of the turbine blade.

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