Element measurement method of TiAl alloy

Abstract

The invention discloses an element measurement method of a TiAl alloy, and belongs to the technical field of element content measurement. The element measurement method of the TiAl alloy comprises the steps that a TiAl alloy sample is provided and placed in an electronic probe instrument, and the TiAl alloy sample contains the boron element; carrying out surface distribution measurement on the boron element on the TiAl alloy sample under the first beam to obtain a first measurement result; surface distribution measurement of major elements is carried out on the TiAl alloy sample under a second beam, a second measurement result is obtained, and the first beam is larger than the second beam; and determining an element measurement result of the TiAl alloy sample according to the first measurement result and the second measurement result. The method realizes accurate measurement of the content of the ultra-light element boron in the TiAl alloy sample.

Description

Technical Field

[0001] This application relates to the field of element content measurement technology, and in particular to a method for element measurement of TiAl alloy. Background Technology

[0002] Titanium-aluminum alloys (TiAl alloys) have broad application prospects in aerospace, automotive, and other fields due to their high specific strength, good high-temperature performance, and excellent creep resistance. However, TiAl alloys are prone to compositional segregation during preparation and processing, especially grain boundary segregation of the ultralight element boron (B), which seriously affects the mechanical properties and service life of the material. Therefore, accurately determining the content and distribution characteristics of boron in TiAl alloys is of great significance for optimizing material composition design and improving material performance.

[0003] Electron probe microanalysis (EPMA) is a commonly used technique for micro-area compositional analysis, enabling high spatial resolution detection of major and trace elements in materials. However, boron (B) has a low atomic number (Z=5) and its Kα line energy is only 1.8 keV, placing it in the category of ultralight elements. Therefore, under conventional EPMA conditions, the X-ray intensity produced by boron is extremely low, resulting in a poor signal-to-noise ratio, which is insufficient to meet the requirements for accurate detection of trace boron (<100 ppm) in TiAl alloys. Summary of the Invention

[0004] The main objective of this application is to provide a method for measuring the elements in TiAl alloys, which enables accurate measurement of the content of the ultralight element boron in TiAl alloy samples.

[0005] To achieve the above objectives, this application provides a method for elemental measurement of TiAl alloys, comprising the following steps: A TiAl alloy sample is provided and placed in an electron probe microanalysis instrument, wherein the TiAl alloy sample contains boron. The surface distribution of boron in the TiAl alloy sample was measured under the first beam current, and the first measurement result was obtained. The surface distribution of major elements in the TiAl alloy sample was measured under a second beam current to obtain a second measurement result, wherein the first beam current is greater than the second beam current; Based on the first measurement result and the second measurement result, the elemental measurement results of the TiAl alloy sample are determined.

[0006] In one embodiment, the elemental measurement results include: point analysis results of boron content and point analysis results of major element content. The step of determining the elemental measurement results of the TiAl alloy sample based on the first measurement results and the second measurement results includes: Based on the first measurement results, point analysis results of boron content corresponding to multiple target locations are determined; Based on the second measurement results, point analysis results of the main element content corresponding to multiple target locations are determined.

[0007] In one embodiment, the first beam current is 80~150 nA and the beam spot diameter is 0.8~1.5 μm.

[0008] In one embodiment, the second beam current is 20~50 nA and the beam spot diameter is 3~6 μm.

[0009] In one embodiment, the accelerating voltage for measuring the surface distribution of boron in the TiAl alloy sample is 3~8kV, and the dwell time is 20~50 ms.

[0010] In one embodiment, the accelerating voltage for measuring the surface distribution of major elements in the TiAl alloy sample is 12~17 kV, and the residence time is 8~15 ms.

[0011] In one embodiment, before placing the TiAl alloy sample on an electron probe microanalyzer, the method further includes: The TiAl alloy sample was subjected to ion polishing; Conductive films were prepared on the surface of TiAl alloy samples after ion polishing.

[0012] In one embodiment, the accelerating voltage for ion polishing is 0.5~2 kV, and the beam current density is 0.1~0.5 mA / cm². 2 The temperature is -25 to -10 ℃.

[0013] In one embodiment, the conductive film is an iridium conductive film with a thickness of 0.5~2 nm.

[0014] In one embodiment, the boron doping amount in the TiAl alloy sample is 0.1~1.0 at.%.

[0015] One or more technical solutions proposed in this application have at least the following technical effects: A method for elemental measurement of TiAl alloy is provided by placing a provided TiAl alloy sample containing boron in an electron probe microanalysis (EPMA) instrument; then, the surface distribution of boron in the TiAl alloy sample is measured under a high first beam current to obtain a first measurement result. Since boron (B) belongs to the category of ultralight elements, its signal is weak under conventional beam currents and easily drowned out by background noise. Therefore, this application uses a high first beam current to bombard the sample, significantly increasing the number of incident electrons, thereby enhancing the excitation efficiency of characteristic X-rays of boron and breaking through the sensitivity bottleneck of ultralight element detection. Then, the surface distribution of major elements in the TiAl alloy sample is measured under a lower second beam current to obtain a second measurement result. Since major elements such as Ti and Al have extremely high X-ray intensity under high beam currents, they easily cause detector saturation in spectrometers or energy spectrometers, resulting in count loss or nonlinear response. At the same time, high beam currents easily damage brittle materials like TiAl. Therefore, this application uses a lower second beam current for major element surface scanning, which can obtain sufficient signals while avoiding sample damage caused by detector saturation and local thermal effects. Based on the first and second measurement results, the elemental measurement results of the TiAl alloy sample were determined. By spatially aligning and co-analyzing the two surface distribution results, not only was the spatial location of element B realized, but the distribution of major elements could also be used to locally absorb and correct for interference in the B signal, significantly improving the accuracy, reliability, and applicability of boron content measurement in TiAl alloys. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of the element measurement method for TiAl alloy involved in the embodiments of this application; Figure 2 This is a backscattered electron image of Example 1 in this application; Figure 3 This is a surface distribution diagram of element B in Embodiment 1 of this application; Figure 4 This is a surface distribution diagram of C elements in Embodiment 1 of this application; Figure 5 This is a surface distribution diagram of Ti element in Embodiment 1 of this application; Figure 6 This is an Al element surface distribution diagram of Embodiment 1 in this application; Figure 7 This is a surface distribution diagram of Mn elements in Embodiment 1 of this application; Figure 8 This is a surface distribution diagram of Mo element in Embodiment 1 of this application; Figure 9 This is a surface distribution diagram of the W element in Embodiment 1 of this application; Figure 10 This is a schematic diagram of the target location in Embodiment 1 of this application. Figure 11 This is a backscattered electron image of Comparative Example 1 in the embodiments of this application; Figure 12 This is a surface distribution diagram of Ti element in Comparative Example 1 of this application; Figure 13 This is a surface distribution diagram of Al element in Comparative Example 1 of this application; Figure 14 This is a surface distribution diagram of Mn element in Comparative Example 1 of this application; Figure 15 This is a surface distribution diagram of Mo element in Comparative Example 1 of this application; Figure 16 This is a surface distribution diagram of the W element in Comparative Example 1 of this application; Figure 17 This is a surface distribution diagram of element B in Comparative Example 1 of this application. Figure 18 This is a surface distribution diagram of C element in Comparative Example 1 of this application.

[0017] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0019] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the elemental measurement method for TiAl alloys according to this application. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of essentially the same structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0020] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0022] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0023] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0024] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0025] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0026] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the technical solution of this application is further described below in conjunction with the accompanying drawings and embodiments. However, this application is not limited to the listed embodiments, but should also include any other well-known modifications within the scope of the claims made in this application.

[0027] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0028] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0029] Electron probe microanalysis (EPMA) is a commonly used technique for micro-area compositional analysis, enabling high spatial resolution detection of major and trace elements in materials. However, boron (B) has a low atomic number (Z=5) and its Kα line energy is only 1.8 keV, placing it in the category of ultralight elements. Therefore, under conventional EPMA conditions, the X-ray intensity produced by boron is extremely low, resulting in a poor signal-to-noise ratio, which is insufficient to meet the requirements for accurate detection of trace boron (<100 ppm) in TiAl alloys.

[0030] In this embodiment, a boron-containing TiAl alloy sample is placed in an electron probe microanalysis (EPMA) instrument. The surface distribution of boron in the TiAl alloy sample is then measured under a high first beam current, yielding a first measurement result. Since boron (B) is an ultralight element, its signal is weak under conventional beam currents and easily drowned out by background noise. Therefore, this embodiment uses a high first beam current to bombard the sample, significantly increasing the number of incident electrons and thus enhancing the excitation efficiency of characteristic X-rays of boron, overcoming the sensitivity bottleneck in ultralight element detection. The surface distribution of major elements in the TiAl alloy sample is then measured under a lower second beam current, yielding a second measurement result. Because major elements such as Ti and Al have extremely high X-ray intensities under high beam currents, they can easily cause detector saturation in spectrometers or energy dispersive spectrometers, resulting in count loss or nonlinear response. Furthermore, high beam currents can easily damage brittle materials like TiAl. Therefore, this embodiment uses a lower second beam current for major element surface scanning, which obtains sufficient signals while avoiding sample damage caused by detector saturation and localized thermal effects. Based on the first and second measurement results, the elemental measurement results of the TiAl alloy sample are then determined. By spatially aligning and co-analyzing the two surface distribution results, not only was the spatial location of element B realized, but the distribution of major elements could also be used to locally absorb and correct for interference in the B signal, which significantly improved the accuracy, reliability and applicability of boron content measurement in TiAl alloys.

[0031] The first aspect of this application provides a method for elemental measurement of TiAl alloys, referring to... Figure 1 This includes the following steps: Step S10: Provide a TiAl alloy sample and place it in an electron probe microanalysis instrument, wherein the TiAl alloy sample contains boron. In one feasible embodiment, a TiAl alloy sample is provided and placed in the test tray of an electron probe instrument. A vacuum is drawn, the heating current of the electron gun is adjusted, and the TiAl alloy sample is moved to the area to be analyzed for measurement.

[0032] Optionally, due to the complex composition of TiAl alloys, compositional and morphological observations can be performed first using electron probe backscattered electron imaging (EPI) to identify potential boride regions within the TiAl alloy sample. These regions can then be used as the analysis targets for subsequent quantitative analysis using EPI. Backscattered electron imaging allows for the clear identification of potential boride phases (such as TiB2) within the TiAl alloy based on differences in atomic number contrast. Combined with morphological characteristics (such as grain boundary precipitation, rod-like / granular structures) and high brightness contrast, the analysis area can be quickly delineated, and B enrichment can be preliminarily confirmed using EDS (energy dispersive spectroscopy). This method provides a reliable target area for subsequent high-precision quantitative analysis of boron using EPI, serving as a crucial preliminary step in achieving analysis "from macroscopic to microscopic, from qualitative to quantitative."

[0033] Optionally, the TiAl alloy sample can be pre-ground, polished, and lightly etched before being placed in an electron probe microanalyzer for subsequent measurements.

[0034] Optionally, the TiAl alloy sample contains heavy elements such as Mo, W, and Mn, with a total content of 1.0~10.0 wt.%.

[0035] Optionally, the TiAl alloy sample contains boron, and the amount of boron incorporated is 0.1~1.0 at.%.

[0036] In one feasible embodiment, before placing the TiAl alloy sample on the electron probe microanalysis instrument, the method further includes: Step S11: Ion polishing is performed on the TiAl alloy sample; In one feasible embodiment, the TiAl alloy sample is pre-polished by ion polishing. Traditional mechanical polishing introduces a plastic deformation layer, residual stress, and microcracks onto the TiAl alloy surface, especially causing spalling or tailing of brittle boride phases, which severely affects the accuracy of backscattered electron imaging and electron probe microanalysis. Therefore, this embodiment uses ion polishing, which removes surface material through non-contact sputtering, thereby eliminating the mechanical damage layer, obtaining an atomically smooth surface, and preserving the true morphology of grain boundaries and precipitates.

[0037] Optionally, the accelerating voltage for ion polishing is 0.5~2 kV. For example, the accelerating voltage for ion polishing can be 0.5 kV, 0.6 kV, 0.7 kV, 0.8 kV, 0.9 kV, 1 kV, 1.1 kV, 1.2 kV, 1.3 kV, 1.4 kV, 1.5 kV, 1.6 kV, 1.7 kV, 1.8 kV, 1.9 kV, 2 kV, etc. High-energy ion bombardment (e.g., >3 kV) can lead to increased atomic displacement on the TiAl alloy surface, forming an amorphous layer that masks the true structure of grain boundaries and borides. However, the 0.5~2 kV ion kinetic energy selected in this embodiment is moderate, mainly inducing physical sputtering of surface atoms rather than deep damage, effectively avoiding amorphization. Meanwhile, ions at 0.5–2 kV incident at a grazing angle achieve uniform and isotropic surface etching, significantly reducing the etching rate difference between the hard phase and the substrate, thereby suppressing spurious diffusion of the B signal and reducing the B tailing effect. Furthermore, the shallow depth of the 0.5–2 kV ions is beneficial for revealing the true distribution width of B near grain boundaries, thus improving spatial resolution.

[0038] Optionally, the beam current density is 0.1~0.5 mA / cm². 2 For example, the beam current density is 0.1 mA / cm². 2 0.2 mA / cm 2 0.3 mA / cm 2 0.4 mA / cm 2 0.5 mA / cm 2 Element B has a small atomic mass, and under high beam current densities (e.g., >1 mA / cm²), it is more susceptible to damage. 2 These particles are more easily sputtered by ion bombardment, leading to surface boron depletion. Therefore, in this application, embodiments use 0.1~0.5 mA / cm². 2 The low beam current density ensures a moderate sputtering rate, minimizing the difference in sputtering yield between B and Ti / Al, achieving near-equal-proportional removal. Within this beam current density range, the surface concentration loss of B can be effectively controlled, far superior to traditional polishing, thus ensuring that subsequent electron probe microanalysis detects the true bulk composition, rather than a "modified surface." Simultaneously, the low beam current density means low energy input per unit area, avoiding thermal migration or phase transitions of B atoms caused by localized temperature rises.

[0039] Optionally, the temperature is -25 to -10 °C. For example, temperatures of -25 °C, -20 °C, -15 °C, and -10 °C are used. Boron (B) has a high diffusion coefficient in TiAl alloys, and especially above room temperature, it readily undergoes thermally activated diffusion along grain boundaries. During ion polishing, despite the low beam current density, localized temperature rises still occur, promoting the migration of B atoms from the grain interior to the grain boundaries, resulting in pseudo-segregation. Therefore, this embodiment uses a low-temperature environment for ion polishing, significantly reducing atomic thermal vibration energy and "freezing" B atoms in their original positions, maintaining their natural distribution. Simultaneously, the low temperature helps maintain the chemical potential balance at grain boundaries, preventing phase separation or coarsening of precipitated phases due to thermal disturbance.

[0040] In this embodiment, a "full-chain protection" for element B is formed through the three-parameter collaborative design of ion polishing, namely anti-sputtering, anti-migration, and anti-distortion, providing an ideal surface with "zero interference" for subsequent dual-beam surface scanning and improving the accuracy of element content detection.

[0041] Step S12: Prepare a conductive film on the surface of the TiAl alloy sample after ion polishing.

[0042] In one feasible embodiment, an iridium conductive film is prepared on the surface of an ion-polished TiAl alloy sample, wherein the thickness of the conductive film is 0.5~2 nm. In electron probe microanalysis, non-conductive or weakly conductive samples (such as TiAl alloys) need to be coated with a conductive film to prevent charge accumulation. Traditionally, carbon films are often used because of their low electron yield and low background interference. However, for the detection of the ultralight element B, carbon films are prone to amorphous structures, leading to uneven electron scattering, and their absorption of extremely low-energy X-rays is still significant. At the same time, it is difficult to suppress the surface migration of B atoms under electron beam bombardment. Based on this, this embodiment selects iridium as the conductive film, which satisfies the conductivity requirement, minimizes the absorption of B Kα rays, and suppresses B migration through high formation energy, achieving a three-in-one effect of "conductivity + B protection + signal enhancement".

[0043] Under electron beam bombardment, B atoms may undergo surface segregation or evaporation due to energy input. However, the Ir-B bond energy formed by iridium and boron is relatively high. Therefore, it is difficult for B atoms to diffuse from the TiAl matrix to the surface and react with Ir. The Ir layer on the sample surface forms a "chemical barrier" that prevents B atoms from migrating to the vacuum interface, thereby reducing the "false loss" or "surface enrichment" of B.

[0044] Optionally, the thickness of the conductive film can be 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1 nm, 1.1 nm, 1.2 nm, 1.3 nm, 1.4 nm, 1.5 nm, 1.6 nm, 1.7 nm, 1.8 nm, 1.9 nm, 2 nm, etc. Since the Kα rays of beta rays have extremely low energy and belong to the soft X-ray category, they are easily absorbed by any covering layer. Therefore, the embodiments of this application use a thinner conductive film to achieve an optimal balance between conductivity and transmittance.

[0045] Step S20: The surface distribution of boron in the TiAl alloy sample is measured under the first beam current to obtain the first measurement result; In one feasible embodiment, the surface distribution of boron in a TiAl alloy sample is measured under a first beam current of 80~150 nA to obtain a first measurement result, wherein the beam spot diameter is 0.8~1.5 μm, the accelerating voltage is 3~8 kV, and the residence time is 20~50 ms.

[0046] Optionally, the first measurement result can be a surface distribution map of ultralight elements, including B, C, etc.

[0047] Optionally, the accelerating voltage under the first beam current can be 3 kV, 4 kV, 5 kV, 6 kV, 7 kV, 8 kV, etc. Since the ionization threshold of the K shell of element B is low, its X-ray generation efficiency can reach its peak at low voltage. Therefore, in this embodiment, an accelerating voltage of 3-8 kV is selected, making the electron beam energy slightly higher than the critical ionization energy of B, but far lower than the higher excitation energy regions of Ti and Al. This results in shallow electron penetration depth, concentrating on the surface layer, which is beneficial for capturing B signals from grain boundaries or precipitated phases, and avoids high-energy electrons penetrating deep into the matrix and bouncing back, causing signal "tailing" and reducing backscattering interference.

[0048] Optionally, the first beam current can be 80 nA, 90 nA, 100 nA, 110 nA, 120 nA, 130 nA, 140 nA, 150 nA, etc. The beam spot diameter can be 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, etc. Since the B signal is extremely weak, a high beam current is required to increase X-ray yield. Therefore, this application uses a high beam current (first beam current), which can still ensure sufficient electron flux under low voltage. Simultaneously, a beam spot diameter of 0.8~1.5 μm enables micro-area focusing, which helps to accurately locate small regions such as grain boundaries and TiB2 precipitates, avoiding signal "contamination" from adjacent phases. This embodiment maximizes the B signal intensity without sacrificing spatial resolution through a combination of high beam current and small beam spot diameter, significantly improving the signal-to-noise ratio.

[0049] Optionally, the dwell time of the first beam can be 20 ms, 25 ms, 30 ms, 35 ms, 40 ms, 45 ms, 50 ms, etc. If the dwell time is too short, the count will be insufficient and the statistical error will be large. If the dwell time is too long, the cumulative electron dose will be high, which may lead to local heating or B migration. Therefore, in this embodiment, the dwell time is determined to be 20~50 ms based on the balance between B signal intensity and electron dose.

[0050] Optionally, since the Kα rays of boron have low energy, conventional spectroscopic crystals are difficult to achieve efficient diffraction. Therefore, in this embodiment, LDE2H type layered synthetic crystals are selected, which is beneficial to improve the diffraction efficiency and peak-to-background ratio of B Kα rays and improve measurement accuracy.

[0051] Step S30: The surface distribution of major elements in the TiAl alloy sample is measured under the second beam current to obtain a second measurement result, wherein the first beam current is greater than the second beam current; In one feasible embodiment, for the same measurement position and magnification, the surface distribution of major elements of TiAl alloy samples is measured under a second beam current of 20~50 nA to obtain a second measurement result, wherein the beam spot diameter is 3~6 μm, the accelerating voltage is 12~17 kV, and the residence time is 8~15 ms.

[0052] Optionally, the second measurement result can be a surface distribution map of the principal elements.

[0053] Optionally, the accelerating voltage under the second beam can be 12 kV, 13 kV, 14 kV, 15 kV, 16 kV, 17 kV, etc. The accelerating voltage under the second beam in this embodiment can form a voltage gradient with the first beam, which facilitates the calculation of the absorption term in subsequent ZAF correction, and the electron interaction volume is moderate, which can avoid the signal coming from deep layers or adjacent grains.

[0054] Optionally, the second beam current can be 20 nA, 30 nA, 40 nA, 50 nA, etc. The beam spot diameter can be 3 μm, 4 μm, 5 μm, 6 μm, etc. TiAl is a major element, and its X-ray signal is strong, which can easily lead to detector saturation or nonlinear response. Therefore, the embodiment of this application uses a low beam current (second beam current) to effectively control the signal intensity within the linear range of the detector. Combined with a large beam spot, it reduces the current density and avoids local overheating that could lead to boron atom migration, grain boundary cracking, or phase decomposition.

[0055] Optionally, the dwell time of the second beam can be 8 ms, 9 ms, 10 ms, 11 ms, 12 ms, 13 ms, 15 ms, etc. Since the principal element signals are strong, a high signal-to-noise ratio can be obtained without a long dwell time. Therefore, this embodiment uses a short dwell time of 8-15 ms to accelerate the scanning speed, so that the principal element surface distribution map (i.e., the second measurement result) can be completed in a similar time as the B map (i.e., the first measurement result), reducing the influence of environmental drift.

[0056] Step S40: Determine the elemental measurement results of the TiAl alloy sample based on the first measurement result and the second measurement result.

[0057] In one feasible embodiment, both the first measurement result and the second measurement result are surface distribution maps of elements. In order to further determine a more accurate point content of elements, multiple target locations can be predetermined. Then, based on the first measurement result, point analysis is performed on the multiple target locations to obtain point analysis results of the boron content of the multiple target locations. Based on the second measurement result, point analysis is performed on the multiple target locations to obtain point analysis results of the main element content of the multiple target locations.

[0058] Optionally, the average value of the point analysis results from multiple target locations can be taken as the final element point analysis result.

[0059] Optionally, to ensure data uniformity, point analysis can be performed at multiple target locations. For example, three target locations are selected, and point analysis is performed on these three locations based on the first measurement result to obtain the point analysis results of boron content at the three target locations. The average of these three results is then taken as the point analysis result of boron content. Similarly, based on the second measurement result, point analysis is performed on the above three target locations to obtain the point analysis results of the main element content at the three target locations. The average of these three results is then taken as the point analysis result of boron content. Since the boride region is narrow and much smaller than the excitation region of characteristic X-rays, the content varies greatly. Therefore, repeating point analysis at the same location will lead to significant deviations in the results. Therefore, different target locations are selected in this embodiment.

[0060] Optionally, during point analysis, an LDE2H crystal can be used under standard focusing conditions (191.319 mm) to accurately obtain the net characteristic X-ray intensity of boron and other major elements through peak counting at 20 ms and background counting at 10 ms. This intensity can then be compared with that of a standard sample with known content and matrix correction (such as ZAF) can be performed to achieve high-precision quantitative analysis of boron content at the micrometer scale.

[0061] In this embodiment, a boron-containing TiAl alloy sample is placed in an electron probe microanalysis (EPMA) instrument. The surface distribution of boron in the TiAl alloy sample is then measured under a high first beam current, yielding a first measurement result. Since boron (B) is an ultralight element, its signal is weak under conventional beam currents and easily drowned out by background noise. Therefore, this embodiment uses a high first beam current to bombard the sample, significantly increasing the number of incident electrons and thus enhancing the excitation efficiency of characteristic X-rays of boron, overcoming the sensitivity bottleneck in ultralight element detection. The surface distribution of major elements in the TiAl alloy sample is then measured under a lower second beam current, yielding a second measurement result. Because major elements such as Ti and Al exhibit extremely high X-ray intensity under high beam currents, they can easily cause detector saturation in spectrometers or energy dispersive spectrometers, resulting in count loss or nonlinear response. Furthermore, high beam currents can easily damage brittle materials like TiAl. Therefore, this embodiment uses a lower second beam current for major element surface scanning, which obtains sufficient signals while avoiding sample damage caused by detector saturation and localized thermal effects. Based on the first and second measurement results, the elemental measurement results of the TiAl alloy sample are then determined. By spatially aligning and co-analyzing the two surface distribution results, not only was the spatial location of element B realized, but the distribution of major elements could also be used to locally absorb and correct for interference in the B signal, which significantly improved the accuracy, reliability and applicability of boron content measurement in TiAl alloys.

[0062] In order to enable those skilled in the art to clearly understand the details and operations of the above embodiments of this application, and to demonstrate the significant improvement in performance of the embodiments of this application, the above technical solutions are illustrated below through multiple embodiments.

[0063] Example 1 (1) Provide a TiAl alloy sample and perform ion polishing on the TiAl alloy sample. The accelerating voltage for ion polishing is 1 kV and the beam current density is 0.3 mA / cm². 2 The temperature is -20 ℃; (2) A 1 nm iridium conductive film was prepared on the surface of the TiAl alloy sample after ion polishing; (3) Place the sample in the electron probe microanalyzer and determine the area to be analyzed (refer to...). Figure 2 The surface distribution of ultralight elements in the TiAl alloy sample was measured under the first beam current of 100 nA, a beam spot diameter of 1.1 μm, an accelerating voltage of 5 kV, and a residence time of 30 ms. The surface distribution measurement results of ultralight elements were obtained by referring to... Figure 3 and 4 Therefore, under these conditions, it is possible to achieve the processing of ultralight elements B (such as...). Figure 3 ) and C (such as Figure 4 Accurate detection; (4) For the same region to be analyzed, the surface distribution of major elements in the TiAl alloy sample was measured under the second beam current, where the second beam current was 20 nA, the beam spot diameter was 3.2 μm, the accelerating voltage was 13 kV, and the residence time was 10 ms; the surface distribution measurement results of major elements were referred to Figures 5 to 9 Therefore, under these conditions, it is possible to achieve the control of the principal element Ti (such as...). Figure 5 ), Al (such as) Figure 6 ), Mn (such as Figure 7 ), Mo (such as Figure 8 ) and W (such as Figure 9 Accurate detection; (5) Determine the target location in the area to be analyzed and perform point analysis on some elements, referring to... Figure 10 The target locations 1 to 3 are shown in Table 1 below.

[0064] Table 1:

[0065] Comparative Example 1 (1) Provide a TiAl alloy sample and perform mechanical polishing on the TiAl alloy sample; (2) Place the sample in the electron probe microanalyzer and determine the area to be analyzed (refer to...). Figure 11 The surface distribution of ultralight elements and major elements in the TiAl alloy sample was measured under a third beam current of 20 nA, a beam spot diameter of 3.2 μm, an accelerating voltage of 13 kV, and a residence time of 10 ms. The surface distribution measurement results of the elements are referenced from [reference needed]. Figures 12 to 18 Therefore, under these conditions, it is possible to achieve the control of the principal element Ti (such as...). Figure 12 ), Al (such as) Figure 13 ), Mn (such as Figure 14 ), Mo (such as Figure 15 ) and W (such as Figure 16 Precise detection of ); but for ultralight element B (such as Figure 17 ) and C (such as Figure 18 The detection accuracy of ) is low.

[0066] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the patent protection scope of this application.

Claims

1. A method for elemental measurement of TiAl alloys, characterized in that, The method includes: A TiAl alloy sample is provided and placed in an electron probe microanalysis instrument, wherein the TiAl alloy sample contains boron. The surface distribution of boron in the TiAl alloy sample was measured under the first beam current, and the first measurement result was obtained. The surface distribution of major elements in the TiAl alloy sample was measured under a second beam current to obtain a second measurement result, wherein the first beam current is greater than the second beam current; Based on the first measurement result and the second measurement result, the elemental measurement results of the TiAl alloy sample are determined.

2. The elemental measurement method for TiAl alloy as described in claim 1, characterized in that, The elemental measurement results include: point analysis results of boron content and point analysis results of major element content. The step of determining the elemental measurement results of the TiAl alloy sample based on the first measurement results and the second measurement results includes: Based on the first measurement results, point analysis results of boron content corresponding to multiple target locations are determined; Based on the second measurement results, point analysis results of the main element content corresponding to multiple target locations are determined.

3. The elemental measurement method for TiAl alloy as described in claim 1, characterized in that, The first beam current is 80~150nA, and the beam spot diameter is 0.8~1.5 μm.

4. The elemental measurement method for TiAl alloy as described in claim 1, characterized in that, The second beam current is 20~50 nA, and the beam spot diameter is 3~6 μm.

5. The elemental measurement method for TiAl alloy as described in claim 1, characterized in that, The accelerating voltage for measuring the surface distribution of boron in the TiAl alloy sample was 3~8 kV, and the residence time was 20~50 ms.

6. The elemental measurement method for TiAl alloy as described in claim 1, characterized in that, The accelerating voltage for measuring the surface distribution of major elements in the TiAl alloy sample was 12~17 kV, and the residence time was 8~15 ms.

7. The method for elemental measurement of TiAl alloy as described in claim 1, characterized in that, Before placing the TiAl alloy sample on an electron probe microanalyzer, the procedure further includes: The TiAl alloy sample was subjected to ion polishing; Conductive films were prepared on the surface of TiAl alloy samples after ion polishing.

8. The method for elemental measurement of TiAl alloy as described in claim 7, characterized in that, The accelerating voltage for ion polishing is 0.5~2 kV, and the beam current density is 0.1~0.5 mA / cm². 2 The temperature is -25 to -10 ℃.

9. The method for elemental measurement of TiAl alloy as described in claim 7, characterized in that, The conductive film is an iridium conductive film with a thickness of 0.5~2 nm.

10. The method for elemental measurement of TiAl alloy as described in claim 1, characterized in that, The boron doping content in the TiAl alloy sample was 0.1~1.0 at.%.

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