A method for in-situ tracking trace element distribution in high-temperature alloy

Abstract

The present application belongs to the field of material composition analysis, and particularly relates to a method for quasi-in-situ tracking of trace element distribution of high-temperature alloy. The high-temperature alloy sample is selected, and the surface of the sample is processed into a mirror surface; the target position pattern of the sample surface is marked, and after the marking, the surface of the sample is processed into a mirror surface again; the sample is placed into a micro-area X-ray fluorescence analysis device, and after the positioning, micro-area X-ray fluorescence analysis is performed; after the fluorescence analysis of the sample, high-temperature treatment is performed, and then the thickness of the oxide layer is determined by using a size measurement technology; the ion thinning device is used to remove the oxide layer; after the positioning of the sample with the removed oxide layer, the sample is placed into the micro-area X-ray fluorescence analysis device, and micro-area X-ray fluorescence analysis is performed, so that the quasi-in-situ tracking of the relative change of the trace element distribution under the high-temperature treatment condition is realized. The present application can accurately and quantitatively obtain the content of the trace element of the high-temperature alloy, and on the other hand, the best distribution position of the trace element can be optimized and determined, so that the processing and treatment process is determined.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of material composition analysis, and particularly relates to a method for quasi-in-situ tracking of trace element distribution of high-temperature alloy. BACKGROUND

[0002] High-temperature alloy refers to high-alloyed iron-based, nickel-based and cobalt-based austenitic metallic material capable of working at high temperature above 600 DEG C, capable of bearing high complex stress, and having surface stability. It is an irreplaceable key structural material for high-temperature parts of aero-engine and gas turbine, and is widely used in turbine blade, guide vane, turbine disc and combustion chamber. The quality of high-temperature alloy determines the performance of engine and gas turbine.

[0003] High-temperature alloy generally contains 10-20 elements. In high-temperature alloy, a plurality of trace elements may form segregation in dendrite or grain boundary, form low-melting point phase, or promote harmful phase precipitation, and even form inclusions, which become a channel for crack generation and propagation. Local enrichment of these trace elements can significantly affect the mechanical properties of high-temperature alloy, such as reducing high-temperature tensile plasticity, high-temperature fatigue and creep properties. In directional solidification columnar crystal high-temperature alloy and directional solidification single crystal high-temperature alloy, the content control requirements of P, Pb, Sb, As, Sn, Bi, Ag, Ga, Ti, Te, Se and other elements are strict, and often one or more elements need to be controlled to less than 10 ppm. This poses a challenge to the precision of alloy chemical composition analysis technology. Under the premise of unchanged trace element content control level, by changing the high-temperature heat treatment conditions, the relative distribution changes of trace elements in grain boundary and intracrystalline, dendrite and interdendrite, primary dendrite, secondary dendrite and tertiary dendrite, and eutectic and non-eutectic structure at different heat treatment temperatures are studied, so that the trace elements are distributed in the best position, thereby exerting the maximum potential of the alloy under the same composition and obtaining excellent comprehensive performance. These studies require some non-destructive quasi-in-situ tracking technology.

[0004] Current technologies cannot achieve non-destructive, quasi-in-situ tracking of the distribution of elements with concentrations less than 10 ppm at high temperatures. The analytical precision of energy-dispersive X-ray spectroscopy (EDS) using scanning electron microscopy is at most 100 ppm; X-ray fluorescence spectrometry (XRF) also has a precision of at least 100 ppm; electron probe microanalysis (EPMA) has a precision of tens of ppm; time-of-flight secondary ion mass spectrometry (TOF-MS) achieves precision in the ppm range, but it is a destructive technique, and its quantitative capabilities are severely limited because it only collects a portion of the ions; inductively coupled plasma mass spectrometry (ICP-MS) also achieves precision in the ppm range, but it is also a destructive technique and cannot repeatedly measure and track relative changes in elemental distribution. For researchers, the ability to analyze elements with concentrations less than 10 ppm and to achieve quasi-in-situ tracking of their relative distribution changes at high temperatures will help optimize processes, improve the mechanical properties of high-temperature alloys, and accelerate their application in engines and gas turbines. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a method for quasi-in-situ tracking of the distribution of trace elements in high-temperature alloys. This method can be used to track the relative changes in the distribution of elements with a content of less than 10 ppm under high-temperature treatment conditions.

[0006] The technical solution of this invention is as follows:

[0007] A method for quasi-in-situ tracking of trace element distribution in high-temperature alloys includes the following steps:

[0008] Step 1: Select a high-temperature alloy sample and use surface treatment technology to treat the sample surface to a mirror finish;

[0009] Step 2: Mark the target location pattern on the surface of the mirror sample from Step 1 using marking technology;

[0010] Step 3: The marked sample is then treated with surface treatment technology to achieve a mirror finish.

[0011] Step 4: Immediately place the sample obtained in Step 3 into the micro-area X-ray fluorescence analysis device. Using the positioning technology, select the target region ROI in the marked area and perform micro-area X-ray fluorescence analysis. Repeat the measurement multiple times to obtain the trace element distribution results 1.

[0012] Step 5: Perform high-temperature treatment on the sample after micro-area X-ray fluorescence analysis;

[0013] Step 6: Determine the oxide layer thickness of the sample after high-temperature treatment using dimensional measurement technology;

[0014] Step 7: After determining the oxide layer thickness, remove the oxide layer at the ROI using an ion thinning device;

[0015] Step 8: the sample without the oxide layer is placed in a micro-area X-ray fluorescence analysis device, a target area ROI is selected in the marked area by using a positioning technology, micro-area X-ray fluorescence analysis is carried out, multiple repeated measurements are carried out, and microelement distribution results 2 are obtained;

[0016] Step 9: steps 5-8 are repeated to obtain multiple element distribution results, and relative changes in microelement distribution under high-temperature treatment conditions are realized.

[0017] The method for tracking microelement distribution of the superalloy in situ, in step 1, the superalloy sample includes various types of superalloys developed or being developed at home and abroad.

[0018] The method for tracking microelement distribution of the superalloy in situ, in step 1, the surface treatment technology is a metallographic polishing technology, an electrolytic polishing technology or an ion cleaning technology.

[0019] The method for tracking microelement distribution of the superalloy in situ, in step 2, the marking technology is a hardness pit technology, a laser marking technology, a manual marking or an ion processing technology; and the marking pattern includes any one of easily identifiable patterns such as a triangle, a quadrilateral, a pentagon, a flower and a cone.

[0020] The method for tracking microelement distribution of the superalloy in situ, in step 4, the micro-area refers to a beam spot size less than 20 μm; and the micro-area X-ray fluorescence analysis device includes a micro-area device based on a laboratory light source or a micro-area device based on a synchrotron radiation light source.

[0021] The method for tracking microelement distribution of the superalloy in situ, in step 4, the positioning technology refers to an optical microscope positioning, a laser positioning or an X-ray positioning technology.

[0022] The method for tracking microelement distribution of the superalloy in situ, in step 4, the microelement refers to an element with a content less than 10 ppm.

[0023] The method for tracking microelement distribution of the superalloy in situ, in step 5, the high-temperature treatment refers to various heat treatments performed at a temperature above 600 DEG C.

[0024] The method for tracking microelement distribution of the superalloy in situ, in step 6, the size measurement technology refers to a screw micrometer, a scanning electron microscope, an X-ray imaging instrument or a laser range finder.

[0025] The method for tracking microelement distribution of the superalloy in situ, in step 7, the ion thinning device includes various devices for micro-nano processing and surface treatment by using an ion beam.

[0026] The design idea of the application is:

[0027] To address the issues of low precision and sample destruction in existing chemical composition analysis techniques, and in response to the need for trace element control in high-temperature alloys, a quasi-in-situ tracking method for the distribution of trace elements in high-temperature alloys has been invented. This method solves the bottleneck problems of optimal location for trace element distribution and process optimization in the field of high-temperature alloys.

[0028] The advantages and beneficial effects of this invention are:

[0029] This invention allows for quasi-in-situ tracking of the relative distribution changes of elements with concentrations less than 10 ppm under high-temperature processing conditions. This invention focuses on the control and optimization of elements at concentrations of 10 ppm or lower. On the one hand, it can accurately quantify the content of trace elements in high-temperature alloys; on the other hand, under the premise of keeping the total content of the same trace element constant, it can optimize and determine its optimal distribution location, thereby determining the processing and treatment techniques, improving mechanical properties such as high-temperature creep, fatigue, and tensile plasticity, and opening up new directions for research in related fields. This invention is not only suitable for high-temperature alloy samples but can also be extended to various metals, ceramics, composite materials, etc. Attached Figure Description

[0030] Figure 1 A schematic diagram of a method for quasi-in-situ tracking of trace element distribution in high-temperature alloys.

[0031] Figure 2 Optical microscopy image (a) and area distribution image (b) of Bi element with a content of approximately 0.5 ppm, obtained from micro-area X-ray fluorescence analysis. Detailed Implementation

[0032] like Figure 1 As shown, in the specific implementation process, the quasi-in-situ tracking method for trace element distribution in high-temperature alloys includes the following steps: selecting a high-temperature alloy sample and treating the sample surface to a mirror finish; marking the target position pattern on the sample surface, and then treating the sample surface to a mirror finish again; placing it in a micro-area X-ray fluorescence analysis device, and performing micro-area X-ray fluorescence analysis (μXRF) after positioning, with an analysis precision of sub-ppm level, where micro-area refers to a beam spot size of less than 20μm, which can reach 5-10μm; subjecting the sample after fluorescence analysis to high-temperature treatment, and then determining the oxide layer thickness using dimensional measurement technology; removing the oxide layer using an ion thinning device; positioning the sample after removing the oxide layer, and then placing it in a micro-area X-ray fluorescence analysis device for micro-area X-ray fluorescence analysis, thereby achieving quasi-in-situ tracking of the relative changes in trace element distribution under high-temperature treatment conditions, where high-temperature treatment refers to various heat treatments performed at 600-1500℃, such as long-term creep, long-term aging, long-term rupture, high-temperature fatigue, and solution treatment with holding time of 1-100 hours.

[0033] The application will be described in detail below in conjunction with specific embodiments.

[0034] Example 1

[0035] In this embodiment, the distribution of trace element Bi of DZ640M cobalt-based precipitation-strengthening directional solidification columnar crystal high-temperature alloy is tracked in situ, and the steps are as follows:

[0036] Step 1: the sample surface is treated into a mirror surface by using a metallographic polishing and polishing technology;

[0037] Step 2: the mirror sample of step 1 is etched into an isosceles triangle pattern on the sample surface by using a laser marking technology;

[0038] Step 3: the sample after etching the pattern is treated into a mirror surface by using an ion cleaning technology;

[0039] Step 4: the sample obtained in step 3 is immediately placed into an Attomap micro-area X-ray fluorescence analysis device produced by SIGRAY company in the United States, the sample cavity is vacuumed, an optical microscope in the light path is used to select an ROI area at the top corner of the isosceles triangle pattern, the area size is 0.6mmx0.6mm, a Mo target with an energy of 17.4keV is selected, the beam spot size is adjusted to 8μm, micro-area X-ray fluorescence analysis is carried out in a step scanning mode, and the distribution result 1 of trace element Bi is obtained through 3 repeated measurements, as shown in Figure 2 ;

[0040] Step 5: the sample after fluorescence analysis is heated to 1150℃ and kept for 10 hours;

[0041] Step 6: the sample obtained in step 5 is used to determine that the thickness of the oxide layer is about 1μm by using a scanning electron microscope;

[0042] Step 7: after determining the thickness of the oxide layer, a precise ion etching device is used, the voltage is adjusted to 5kV, the current is adjusted to 2mA, the etching time is 30min, and the oxide layer is completely removed;

[0043] Step 8: the sample after removing the oxide layer is immediately placed into the Attomap micro-area X-ray fluorescence analysis device, the target area of fluorescence analysis in step 4 is selected in the marked area by using a positioning technology, micro-area X-ray fluorescence analysis is carried out, and the distribution result 2 of trace element Bi is obtained through 3 repeated measurements, so as to realize the in-situ tracking of the relative change of the distribution of trace element Bi under high-temperature treatment conditions.

[0044] In this embodiment, the content of Bi element is about 0.5ppm, the detection difficulty is very great, the requirement for surface treatment is very high, and the requirement for removal of the oxide layer is also very high, and any surface contamination will affect the detection signal and the fluorescence analysis result. The application breaks the limitation of the conventional chemical composition analysis technology, and innovatively realizes the high spatial resolution, high precision and nondestructive quasi-in-situ tracking of the relative change of the Bi element distribution under the high temperature treatment condition.

[0045] Embodiment 2

[0046] In this embodiment, the DD406 nickel-based directional solidification single crystal high-temperature alloy is selected to track the quasi-in-situ distribution of trace element Pb, and the steps are as follows:

[0047] Step 1: the sample surface is treated into a mirror surface by using a metallographic grinding and polishing technology;

[0048] Step 2: the mirror sample in step 1 is marked with a triangular pyramid pattern on the sample surface by using a hardness pit technology;

[0049] Step 3: the sample after marking the pattern is treated into a mirror surface by using an ion cleaning technology;

[0050] Step 4: the sample obtained in step 3 is placed into a BL15U1 hard X-ray micro-focusing and application beamline station of Shanghai Synchrotron Radiation Facility; an X-ray positioning technology in the light path is used to select an ROI region at the top angle of the triangular pyramid pattern, and the region size is 0.2mm*0.2mm; a monochromatic light with an energy of 5.4keV is adjusted and used, the beam spot size is adjusted to 10μm, a 10*10 equidistant point array scanning mode is adopted, micro-area X-ray fluorescence analysis is carried out, and after 5 repeated measurements, the distribution result 1 of trace element Pb is obtained;

[0051] Step 5: the sample after fluorescence analysis is heated to 1200℃ and kept for 16 hours;

[0052] Step 6: the sample obtained in step 5 is used to determine that the thickness of the oxide layer is about 1.8μm by using an X-ray three-dimensional imaging technology;

[0053] Step 7: after the thickness of the oxide layer is determined, a precise ion etching device is used, the voltage is adjusted to 5kV, the current is adjusted to 2mA, the etching time is 54min, and the oxide layer is completely removed;

[0054] Step 8: the sample after removing the oxide layer is immediately placed into the BL15U1 hard X-ray micro-focusing and application beamline station of Shanghai Synchrotron Radiation Facility, the positioning technology is used to select the target region for fluorescence analysis in step 4 in the marked region, micro-area X-ray fluorescence analysis is carried out, and after 5 repeated measurements, the distribution result 2 of trace element Pb is obtained, so as to realize the quasi-in-situ tracking of the relative change of the trace element Pb distribution under the high temperature treatment condition.

[0055] In the embodiment, the content of Pb element is about 5ppm, the detection difficulty is great, the requirement for surface treatment is very high, and the requirement for removal of the oxide layer is also very high, and any surface contamination will affect the detection signal and the fluorescence analysis result. The application breaks the limitation of the conventional chemical composition analysis technology, and innovatively realizes the high spatial resolution, high precision and nondestructive quasi in-situ tracking of the relative change of Pb element distribution under high temperature treatment condition.

Claims

1. A method for quasi-in-situ tracking of trace element distribution in high-temperature alloys, characterized in that, Includes the following steps: Step 1: Select a high-temperature alloy sample and use surface treatment technology to treat the sample surface to a mirror finish; Step 2: Mark the target location pattern on the surface of the mirror sample from Step 1 using marking technology; Step 3: The marked sample is then treated with surface treatment technology to achieve a mirror finish. Step 4: Immediately place the sample obtained in Step 3 into the micro-area X-ray fluorescence analysis device. Using the positioning technology, select the target region ROI in the marked area and perform micro-area X-ray fluorescence analysis. Repeat the measurement multiple times to obtain the trace element distribution results 1. Step 5: Perform high-temperature treatment on the sample after micro-area X-ray fluorescence analysis; Step 6: Determine the oxide layer thickness of the sample after high-temperature treatment using dimensional measurement technology; Step 7: After determining the oxide layer thickness, remove the oxide layer at the ROI using an ion thinning device; Step 8: Place the sample with the oxide layer removed into the micro-area X-ray fluorescence analysis device. Using the positioning technology, select the target region ROI in the marked area and perform micro-area X-ray fluorescence analysis. Repeat the measurement multiple times to obtain the elemental distribution results 2. Step 9: Repeat steps 5 to 8 to obtain multiple element distribution results, thereby achieving quasi-in-situ tracking of the relative changes in trace element distribution under high-temperature treatment conditions.

2. The method for quasi-in-situ tracking of trace element distribution in high-temperature alloys according to claim 1, characterized in that, In step 1, the high-temperature alloy samples include various grades of high-temperature alloys that have been developed or are under development both domestically and internationally.

3. The method for quasi-in-situ tracking of trace element distribution in high-temperature alloys according to claim 1, characterized in that, In step 1, the surface treatment technology is metallographic grinding and polishing, electrolytic polishing, or ion cleaning.

4. The method for quasi-in-situ tracking of trace element distribution in high-temperature alloys according to claim 1, characterized in that, In step 2, the marking technology is hardness pitting technology, laser marking technology, manual marking technology, or ion processing technology; the marking pattern includes any easily identifiable shape such as a triangle, quadrilateral, pentagon, flower, or cone.

5. The method for quasi-in-situ tracking of trace element distribution in high-temperature alloys according to claim 1, characterized in that, In step 4, "micro-area" refers to a beam spot size of less than 20 μm; the micro-area X-ray fluorescence analysis device includes a micro-area device based on a laboratory light source or a micro-area device based on a synchrotron radiation light source.

6. The method for quasi-in-situ tracking of trace element distribution in high-temperature alloys according to claim 1, characterized in that, In step 4, the positioning technology refers to optical microscope positioning, laser positioning, or X-ray positioning technology.

7. The method for quasi-in-situ tracking of trace element distribution in high-temperature alloys according to claim 1, characterized in that, In step 4, trace elements refer to elements with a content of less than 10 ppm.

8. The method for quasi-in-situ tracking of trace element distribution in high-temperature alloys according to claim 1, characterized in that, In step 5, high-temperature treatment refers to various heat treatments performed at temperatures above 600°C.

9. The method for quasi-in-situ tracking of trace element distribution in high-temperature alloys according to claim 1, characterized in that, In step 6, the dimensional measurement technology refers to micrometers, scanning electron microscopes, X-ray imaging instruments, or laser rangefinders.

10. The method for quasi-in-situ tracking of trace element distribution in high-temperature alloys according to claim 1, characterized in that, In step 7, the ion thinning device includes various devices that utilize ion beams for micro / nano fabrication and surface treatment.

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