阅读说明：本技术 利用x射线荧光光谱表征高温合金成分分布的原位分析方法 (In-situ analysis method for representing component distribution of high-temperature alloy by utilizing X-ray fluorescence spectrum ) 是由 谢君 侯桂臣 荀淑玲 王振江 周亦胄 孙晓峰 于 2019-12-10 设计创作，主要内容包括：本发明公开了一种利用X射线荧光光谱表征高温合金成分分布的原位分析方法,属于高温合金成分分布表征技术领域。本发明通过以下技术方案予以实现：(1)选择不同类型和含量组成的标准样品组成标准样品库,对标准样品进行表面处理,选择合适的分析条件,并对标准样品光谱进行背景扣除、重叠光谱校正以及基体效应校正,得到标准工作曲线；(2)标定观测区分析点的位置,利用标准工作曲线对待分析试样观测区进行原位分析；(3)处理分析数据,得到系列表征高温合金成分分布的特征参数。本发明可快速、准确地表征高温合金的成分分布情况,定量分析与评价各元素的均匀性及偏析度,为改进现有冶炼工艺、提高高温合金综合性能提供依据。(The invention discloses an in-situ analysis method for representing component distribution of a high-temperature alloy by utilizing an X-ray fluorescence spectrum, belonging to the technical field of component distribution representation of the high-temperature alloy. The invention is realized by the following technical scheme: (1) selecting standard samples with different types and content to form a standard sample library, performing surface treatment on the standard samples, selecting proper analysis conditions, and performing background subtraction, overlapped spectrum correction and matrix effect correction on the standard sample spectrum to obtain a standard working curve; (2) calibrating the position of an analysis point of the observation area, and carrying out in-situ analysis on the observation area of the sample to be analyzed by using a standard working curve; (3) and processing the analysis data to obtain a series of characteristic parameters representing the component distribution of the high-temperature alloy. The method can rapidly and accurately represent the component distribution condition of the high-temperature alloy, quantitatively analyze and evaluate the uniformity and the segregation degree of each element, and provide a basis for improving the existing smelting process and improving the comprehensive performance of the high-temperature alloy.)

1. An in-situ analysis method for characterizing the component distribution of a high-temperature alloy by utilizing an X-ray fluorescence spectrum is characterized by comprising the following steps of: the analysis method comprises the steps of firstly establishing a standard working curve according to the steps (1) to (6), then analyzing an observation area of a sample to be analyzed according to the steps (7) to (9), and finally processing analysis data according to the step (10) to obtain a series of characteristic parameters for representing the distribution of alloy components; the process specifically comprises the following steps:

(1) selecting a standard sample:

selecting standard samples of different types and multiple brands to form a standard sample library, and solving the problem of measuring the content of trace residual elements in the high-temperature alloy by using non-similar standard samples;

(2) treating a standard sample:

carrying out surface treatment on the standard sample by using grinding equipment to ensure that the surface state of the standard sample meets the requirement of quantitative determination; processing the sample by using a grinding wheel saw to ensure that the diameter of the sample is within the range of 20-350 mm;

(3) selecting analysis conditions:

selecting proper analysis conditions according to the characteristics of the analysis elements, putting the standard sample processed in the step (2) into an X-ray fluorescence spectrometer for analysis, and collecting the spectrum of the standard sample;

(4) background subtraction analysis:

carrying out background processing on the obtained standard sample spectrum, and accurately deducting background values of the characteristic spectrum and other spectrum peaks to obtain the net intensity of the characteristic spectrum;

(5) performing overlapping correction on interference spectral lines to obtain the net intensity of the element to be detected;

(6) correcting the matrix effect by using a mathematical correction method to obtain a standard working curve;

(7) treating a sample to be analyzed:

performing surface treatment on the sample to be analyzed by adopting a method consistent with the step (2), and avoiding the influence on the accuracy of an analysis result due to different surface states; processing the sample by using a grinding wheel saw to ensure that the diameter of the sample is within the range of 20-350 mm;

(8) calibrating the position of an observation area of a sample to be analyzed:

selecting a micro-area analysis function of the X-ray fluorescence spectrometer, setting an analysis step length, and calibrating an observation area of a sample to be analyzed by using a division grid of micro-area analysis;

(9) accurately positioning analysis points of an observation area by utilizing a micro-area analysis function, and carrying out in-situ analysis on an observation area of a sample to be analyzed by using an established standard working curve;

(10) processing the analysis data to obtain characteristic parameters representing the component distribution of the high-temperature alloy: two-dimensional and three-dimensional distribution maps of element content, maximum skewness position and maximum segregation degree, content frequency distribution map, statistical uniformity and statistical segregation degree.

2. The in-situ analysis method for characterizing superalloy component distribution using X-ray fluorescence spectroscopy of claim 1, wherein: the X-ray fluorescence spectrum is an energy dispersive X-ray fluorescence spectrum; the high-temperature alloy is iron-based, nickel-based or cobalt-based.

3. The in-situ analysis method for characterizing superalloy component distribution using X-ray fluorescence spectroscopy of claim 1, wherein: the number of the standard samples selected in the step (1) is not less than 30; the type of the standard sample should cover the whole as much as possible so as not to influence the applicability of the working curve; the element content of the standard sample is required to be uniformly covered in the whole content range, so that local dense coverage is avoided.

4. The in-situ analysis method for characterizing superalloy component distribution using X-ray fluorescence spectroscopy of claim 1, wherein: the grinding equipment in the step (2) can adopt a grinder, a sand paper grinding disc or a sand belt grinder, and can also adopt a lathe, a milling machine and the like.

5. The in-situ analysis method for characterizing superalloy component distribution using X-ray fluorescence spectroscopy of claim 1, wherein: the analysis conditions in the step (3) comprise analysis spectral line types, voltage and current of an X-ray tube, optical filter types, attenuator types, analysis time, region-of-interest calibration and correction curve types.

6. The in-situ analysis method for characterizing superalloy component distribution using X-ray fluorescence spectroscopy of claim 1, wherein: the background correction method in the step (4) can adopt an actual measurement background deduction method, a fixed coefficient method, a background channel substitution method or an empirical formula correction method.

7. The in-situ analysis method for characterizing superalloy component distribution using X-ray fluorescence spectroscopy of claim 1, wherein: the mathematical correction method in step (6) may be a basic parameter method, a theoretical influence coefficient method, or an empirical coefficient method.

8. The in-situ analysis method for characterizing superalloy component distribution using X-ray fluorescence spectroscopy of claim 1, wherein: the analysis step size in the step (8) is 0.1mm, 0.25mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 5mm or 10 mm.

9. The in-situ analysis method for characterizing superalloy component distribution using X-ray fluorescence spectroscopy of claim 1, wherein: in the step (10), the maximum segregation degree is defined as: p (x, y) ═ C/C₀Where (x, y) is the position where the maximum segregation occurs, C is the value of the maximum content deviating from the average content of the analytical elements, C₀Is the average content value of the analytical elements; the statistical uniformity is defined as: the weight ratio of the original position occupied by the element-specific content range (quality control range) was analyzed.

10. The in-situ analysis method for characterizing superalloy component distribution using X-ray fluorescence spectroscopy of claim 1, wherein: the statistical segregation degree in the step (10) is defined as: and the 95% confidence coefficient of the median of the content statistical distribution of a certain element in each position of the observation area.

Technical Field

The invention belongs to the technical field of high-temperature alloy component distribution characterization, and particularly relates to an in-situ analysis method for characterizing high-temperature alloy component distribution by using an X-ray fluorescence spectrum.

Background

High temperature alloys are widely used in aircraft engine and industrial gas turbine components due to their good high temperature strength and structural stability, excellent oxidation and corrosion resistance, and fatigue and creep resistance. In order to improve the high-temperature strength and the temperature bearing capacity of the high-temperature alloy, Al, Ti, Ta, Nb and other elements are added into the alloy to increase gamma in the alloy^，The number of phases leads to the continuous improvement of the alloying degree, the solidification segregation becomes more and more serious, the structural stability of the alloy is reduced, the comprehensive performance of the alloy is influenced, and the further development of the alloy is hindered. The research on the segregation condition of each element in the high-temperature alloy is beneficial to improving the existing smelting process and improving the uniformity of the components and the structure of the high-temperature alloy. Therefore, the quantitative analysis method is used for representing the component distribution of the high-temperature alloy, and has important guiding and reference significance for improving the smelting quality of the high-temperature alloy and reducing the component segregation.

At present, the macro-analysis methods for studying segregation are a drilling sampling method and a low-power metallographic analysis technology, and the micro-analysis methods comprise scanning electron microscope/energy spectrum analysis and electron probe micro-analysis, but the methods have certain limitations in representing the composition segregation of the high-temperature alloy. The continuous quantitative distribution of each element in a large-scale range is difficult to obtain due to the discontinuity of sampling points, the limited sampling quantity and the like in the drilling sampling method; the low-power metallographic analysis can only carry out qualitative rating on the center segregation, cannot give quantitative data, and has a limited element analysis range; although the micro analysis technology can provide the component distribution of the micro-area, the observation field range is limited, the analysis efficiency is low, and the micro analysis technology is difficult to be widely applied in the engineering field.

The in-situ statistical distribution analysis (OPA) technique of spark source atomic emission spectrum is a high-flux component distribution analysis technique for large-scale metal cross section developed in the last ten years, and the technique can obtain metal materials in a large-scale range (cm)²) The statistical information such as the position distribution and quantitative distribution of the chemical composition can be obtained by the above methodsThe method has incomparable advantages, but the atomic emission spectrum of the spark source is a spectral analysis method based on outer-layer electron transition, complex characteristic spectral lines exist in each element, and the spectral lines are overlapped seriously, so that the establishment process of the analysis method is relatively complex. Although the diameter of a melting area is small, the single spark discharge excitation still damages the surface of the sample, the analysis method has high requirements on the state of the surface of the sample, and the existence of surface defects can cause the sample to be difficult to excite and cannot obtain an accurate quantitative result; when the content of the analysis element is larger, the accuracy is poorer.

The X-ray fluorescence spectrum has the advantages of no damage to the surface of a sample, high analysis speed, high precision, simple sample preparation, simultaneous detection of multiple elements and the like, and is widely applied to the field of high-temperature alloy quality evaluation. So far, the X-ray fluorescence spectrum is only limited in the aspect of quality supervision application, and no analysis method for characterizing the component distribution of the high-temperature alloy by using the X-ray fluorescence spectrum is available.

Disclosure of Invention

The invention aims to provide an in-situ analysis method for representing the component distribution of a high-temperature alloy by utilizing an X-ray fluorescence spectrum, which realizes the statistical quantitative distribution analysis of the content of each element in the high-temperature alloy to obtain the uniformity information of the alloy components and provides a basis for improving the existing smelting process and improving the alloy performance.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an in-situ analysis method for characterizing the component distribution of a high-temperature alloy by utilizing an X-ray fluorescence spectrum comprises the steps of firstly establishing a standard working curve according to the steps (1) to (6), then analyzing an observation area of a sample to be analyzed according to the steps (7) to (9), and finally processing analysis data according to the step (10) to obtain a series of characteristic parameters for characterizing the component distribution of the alloy; the method specifically comprises the following steps:

(1) selecting a standard sample:

selecting standard samples of different types and multiple brands to form a standard sample library, and solving the problem of measuring the content of trace residual elements in the high-temperature alloy by using non-similar standard samples;

(2) treating a standard sample:

carrying out surface treatment on the standard sample by using grinding equipment to ensure that the surface state of the standard sample meets the requirement of quantitative determination; processing the sample by using a grinding wheel saw to ensure that the diameter of the sample is within the range of 20-350 mm;

(3) selecting analysis conditions:

selecting proper analysis conditions according to the characteristics of the analysis elements, putting the standard sample selected in the step (1) into an X-ray fluorescence spectrometer for analysis, and collecting the spectrum of the standard sample;

(4) background subtraction analysis:

carrying out background processing on the obtained standard sample spectrum, accurately obtaining the background values of the characteristic spectrum and other spectrum peaks, and obtaining the net intensity of the characteristic spectrum;

(5) and (3) correcting spectral line overlapping:

in some cases, there is severe spectral line interference in the X-ray fluorescence spectroscopy, the characteristic spectral lines of some elements overlap, and the spectral line interference needs to be corrected to obtain the net intensity of the element to be measured.

(6) Correcting the matrix effect:

in a multivariate system, absorption effect and enhancement effect exist between the detected element and the coexisting element, so that the analysis intensity value cannot be in a linear change relation with the concentration of the element to be detected, and the matrix effect is corrected by using a mathematical correction method;

(7) treating a sample to be analyzed:

performing surface treatment on the sample to be analyzed by adopting a method consistent with the step (2), and avoiding the influence on the accuracy of an analysis result due to different surface states; processing the sample by using a grinding wheel saw to ensure that the diameter of the sample is within the range of 20-350 mm;

(8) calibrating the position of an observation area of a sample to be analyzed:

setting an analysis step length by using a micro-area analysis function of the X-ray fluorescence spectrometer, and calibrating an observation area of a sample to be analyzed by using a division grid of micro-area analysis;

(9) carrying out in-situ analysis on an observation area of a sample to be analyzed by using the standard working curve established in the steps (1) to (6);

the micro-area analysis function of the X-ray fluorescence spectrometer accurately positions the analysis points of the observation area calibrated in the step (8) and continuously analyzes the set analysis points at fixed points;

(10) processing analytical data

Processing the analysis data to obtain characteristic parameters representing the component distribution of the high-temperature alloy: two-dimensional and three-dimensional distribution maps of element content, maximum skewness position and maximum segregation degree, content frequency distribution map, statistical uniformity and statistical segregation degree.

The X-ray fluorescence spectrum is an energy dispersion X-ray fluorescence spectrum; the superalloy may be an iron-based, nickel-based, or cobalt-based superalloy.

The number of the standard samples selected in the step (1) is not less than 30; the types of the standard samples are completely covered as much as possible, and the occupancy rate of the single type of standard samples cannot be too high so as to avoid influencing the applicability of the working curve; the element content range of the standard sample needs to be uniformly covered in the whole content range, so that the established standard working curve covers the low, medium and high concentration ranges of the elements, and local dense coverage is avoided.

The grinding device in the step (2) can adopt a grinder, a sand paper grinding disc or a sand belt grinder, and can also adopt a lathe, a milling machine and the like.

The analysis conditions in the step (3) include analysis spectral line type, voltage and current of the X-ray tube, filter type, attenuator type, analysis time interesting region calibration and correction curve type.

The background correction method in the step (4) may adopt an actual measurement background subtraction method, a fixed coefficient method, a background channel substitution method, or an empirical formula correction method.

The mathematical correction method in the step (6) may be a basic parameter method, a theoretical influence coefficient method, or an empirical coefficient method.

The analysis step size in the above step (8) may be 0.1mm, 0.25mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 5mm or 10 mm.

The maximum segregation degree in the step (10) is defined as: p (x, y) ═ C/C₀Where (x, y) is the position where the maximum segregation occurs, C is the value of the maximum content deviating from the average content of the analytical elements, C₀Is the average content value of the analytical elements.

The statistical uniformity in the step (10) is defined as: the weight ratio of the original position occupied by the specific content range (quality control range).

The statistical segregation degree in the step (10) is defined as: and the 95% confidence coefficient of the median of the content statistical distribution of a certain element in each position of the observation area.

The invention has the following advantages and beneficial effects:

the in-situ analysis method for characterizing the component distribution of the high-temperature alloy by the X-ray fluorescence spectrum can rapidly and accurately characterize the element distribution condition of the high-temperature alloy, obtain a series of characteristic parameters for characterizing the component distribution, quantitatively analyze and evaluate the uniformity and the segregation degree of each element, and can be used as a basis for improving the existing smelting process and improving the alloy performance; compared with the traditional component distribution characterization method, the method has no damage to the surface of the sample, has the characteristics of large analysis field range, high analysis efficiency, wide analysis element range, quantification and the like, and has very high application value.

Drawings

FIG. 1 is a distribution diagram of FGH97 alloy observation area analysis points;

FIG. 2 is a two-dimensional, three-dimensional distribution plot of Co element content in FGH97 alloy;

FIG. 3 is a graph showing the frequency distribution of the Co content in the FGH97 alloy.

Detailed Description

For a further understanding of the present invention, the following description is given in conjunction with the examples which are set forth to illustrate, but are not to be construed to limit the present invention, features and advantages.

The invention is described in detail below with reference to the figures and examples.

Taking the analysis of the compositional distribution of the FGH97 alloy as an example, the uniformity and segregation degree of each element were evaluated.

(1) Selecting a standard sample:

selecting 32 standard samples of different types such as K417G, K465, DZ40M and the like to form a standard sample library, and solving the content determination problem of trace residual element Mn in the high-temperature alloy by using non-similar standard samples;

(2) treating a standard sample:

performing surface treatment on the standard sample by using a polishing machine, and polishing the standard sample by using 180-mesh silicon carbide abrasive paper to ensure that the surface state of the standard sample meets the requirement of quantitative determination;

(3) selecting analysis conditions:

selecting an energy dispersion X-ray fluorescence spectrum as an analysis channel, recommending and selecting the spectral line type of each analysis element according to SuperQ6.0 software, setting the voltage of an X-ray tube to be 60KV, the current to be 66mA, the type of an attenuator to be SSM, the analysis time to be 240s, setting an interested region by four elements of Hf, Ta, W and Re, and selecting a correction curve type, wherein C is D + ERM, and C is the concentration of the element to be detected; d is the intercept of the correction curve; e is the slope of the correction curve; r is the net strength of the element to be detected; m is used for correcting the absorption enhancement effect between elements, a standard sample is put into an X-ray fluorescence spectrometer for analysis, and the spectrum of the standard sample is collected;

(4) background subtraction analysis:

carrying out background processing on the obtained standard sample spectrum by using an actual measurement background deduction method, accurately obtaining a characteristic spectrum and background values of other spectrum peaks, and obtaining the net intensity of the characteristic spectrum;

(5) carrying out overlapping interference correction on interference spectral lines of elements to be analyzed to obtain element net intensity;

(6) correcting the matrix effect:

the basic parameter method is used for correcting the matrix effect, and the problem that the analysis intensity value cannot be linearly changed with the concentration of the element to be detected is solved. To address the absorption enhancement effect, the SuperQ6.0 software combines several commonly used influence coefficient method correction patterns into one equation:

wherein M is correction coefficient of absorption enhancement effect between elements, Z is concentration or counting rate, N is number of elements to be analyzed, α, β, delta and gamma are factors for matrix correction, i is element to be detected, and j and k are matrix elements.

The basic parametric method used in this embodiment has the following correction mode:

wherein M is an inter-element absorption-enhancement effect correction coefficient; r is theoretical intensity obtained by basic parameter method mode calculation; c is the concentration of the sample; i is an element to be detected; r₀/C₀Is a constant calculated from a pure element sample to be measured; at correction time R₁/C₁Calculated for each standard, R when analyzing unknown samples₁/C₁Calculations are performed at each step of the iteration.

(7) Processed FGH97 sample:

carrying out surface treatment on FGH97 test samples by using a grinding and polishing machine, and selecting 180-mesh silicon carbide abrasive paper to grind the test samples to ensure that the surface state of the test samples is consistent with that of standard samples; processing the size of the sample by using a grinding wheel saw, wherein the diameter of the final sample is 300 mm;

(8) position of observation area of calibration FGH97 sample:

demarcating an FGH97 alloy observation area by using a division grid of micro-area analysis of a Zetium model X-ray fluorescence spectrometer of Pannake company, selecting the analysis step length to be 0.5mm, and selecting 280 analysis points; fig. 1 is a distribution diagram of observation region analysis points.

(9) Accurately positioning the analysis points calibrated in the step (8) by utilizing the micro-area analysis function in the X-ray fluorescence spectrometer, and carrying out in-situ analysis on the observation area of the FGH97 sample by using the established standard working curve;

(10) processing the analysis results

Referring to table 1, the analysis data is processed to obtain characteristic parameters characterizing the distribution of FGH97 components: two-dimensional and three-dimensional distribution maps of element content, maximum skewness position and maximum segregation degree, content frequency distribution map, statistical uniformity and statistical segregation degree; table 2 shows the uniformity of the distribution of different elements in the FGH97 alloy, wherein the segregation degree of Al, Nb, Zr and Hf is more severe, the segregation degree of Co, Cr, W and Ni is less, and the distribution is relatively uniform.

TABLE 1 FGH97 alloy composition line

Cr	Al	Mo	Co	Nb
					8.00-10.00	4.85-5.25	3.50-4.20	15.00-16.50	2.40-2.80
Ti	W	Hf	Zr	Ni
					1.60-2.00	4.80-5.90	0.10-0.40	0.010-0.015	Bal

Fig. 2 is a two-dimensional and three-dimensional distribution diagram of the content of Co element in FGH97 alloy, which visually reflects the distribution of Co element in the alloy and obtains the maximum segregation degree of Co: p (3.5, -9) ═ 1.03; FIG. 3 is a diagram showing the frequency distribution of Co content in the FGH97 alloy, and shows: the statistical uniformity is 100%, and the statistical segregation degree is 0.0010; the characteristic parameters show that the Co element is distributed in the FGH97 alloy more uniformly.

Table 2 in situ analysis characteristic parameters of each element in FGH97