Method for screening nuclear aluminum alloy by in-situ ion irradiation and nuclear aluminum alloy

Abstract

The invention provides a method for screening nuclear aluminum alloy through in-situ ion irradiation and the nuclear aluminum alloy. The method comprises the steps that at least one piece of aluminum alloy to be screened is prepared into a TEM sample; determining at least one in-situ observation area in the TEM sample; performing in-situ ion irradiation on the at least one in-situ observation area under a plurality of simulated irradiation doses, and calculating a plurality of first yield strength increments, corresponding to the plurality of simulated irradiation doses, of the at least one in-situ observation area according to a statistical result of dislocation rings in the at least one in-situ observation area; and screening the nuclear aluminum alloy according to the plurality of first yield strength increments.

Description

Technical Field

[0001] This application mainly relates to the field of nuclear material performance evaluation technology, and in particular to a method for screening nuclear aluminum alloys by in-situ ion irradiation and nuclear aluminum alloys. Background Technology

[0002] Aluminum alloys, due to their low neutron absorption cross-section, good thermal conductivity, and machinability, are widely used in key components of nuclear reactors, such as heavy water tanks and fuel assembly cladding. Therefore, establishing rapid and reliable methods to screen novel aluminum alloys with excellent radiation resistance has become an important research direction in the field of nuclear materials. Currently, aluminum alloy screening methods relying on reactor neutron irradiation experiments can realistically simulate the service environment, but these methods suffer from problems such as long irradiation cycles, high costs, strong radioactivity, and complex post-processing, severely restricting the efficiency of new material development and screening. Existing methods for screening aluminum alloys using ex-situ ion irradiation also have certain limitations: on the one hand, while these methods improve the efficiency of defect introduction, they fail to simultaneously improve characterization efficiency, still requiring complex and time-consuming subsequent microscopic observation and mechanical testing, and do not fundamentally solve the problem of slow screening speed; on the other hand, these methods can only obtain static information at a specific irradiation dose and cannot continuously track the dynamic response of materials during irradiation (e.g., nonlinear evolution behaviors such as hardening followed by softening), thus potentially missing key structure-property evolution laws. Summary of the Invention

[0003] The technical problem to be solved by this application is to provide a method for screening nuclear aluminum alloys by in-situ ion irradiation and the nuclear aluminum alloys. This method is applicable to the evaluation and screening of aluminum alloys with different composition contents, and can realize the rapid and accurate evaluation of the radiation resistance of aluminum alloys, and can study the dynamic evolution process of aluminum alloys during irradiation.

[0004] This application proposes a method for screening nuclear-grade aluminum alloys by in-situ ion irradiation, comprising: preparing at least one aluminum alloy to be screened as a TEM sample; determining at least one in-situ observation region in the TEM sample; subjecting the at least one in-situ observation region to in-situ ion irradiation at multiple simulated irradiation doses; calculating multiple first yield strength increments corresponding to the at least one in-situ observation region and the multiple simulated irradiation doses based on statistical results of dislocation loops in the at least one in-situ observation region; and screening the nuclear-grade aluminum alloy based on the multiple first yield strength increments.

[0005] This application also proposes a nuclear-grade aluminum alloy, which is obtained by screening nuclear-grade aluminum alloys by in-situ ion irradiation screening as described above.

[0006] The technical solution of this application has the following technical effects: by capturing the entire process of irradiation damage of the aluminum alloy to be screened through in-situ irradiation, it is possible not only to continuously track the dynamic evolution process of the aluminum alloy to be screened during the irradiation process, but also to improve the screening speed and the screening accuracy. Attached Figure Description

[0007] The accompanying drawings are included to provide a further understanding of this application; they are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application. In the drawings:

[0008] Figure 1 This is a schematic flowchart of a method for screening nuclear aluminum alloys by in-situ ion irradiation in one embodiment of this application;

[0009] Figure 2 This is a schematic diagram of the evolution of the microstructure of the in-situ observation area with irradiation dose in one embodiment of this application;

[0010] Figure 3 This is a schematic diagram of the process for calculating the first yield strength increment of the in-situ observation region based on the statistical results of dislocation loops in one embodiment of this application;

[0011] Figure 4 This is a schematic outline of a dislocation loop that conforms to the contrast characteristics in one embodiment of this application;

[0012] Figure 5 This is a line graph showing the statistical average size of dislocation loops in one embodiment of this application;

[0013] Figure 6 This is a line graph of the statistical average number density of dislocation loops in one embodiment of this application;

[0014] Figure 7 This is the first fitted curve in one embodiment of this application;

[0015] Figure 8 This is a flowchart illustrating the accuracy of the method for verifying the screening of aluminum alloys for nuclear applications in one embodiment of this application;

[0016] Figure 9 This is a line graph showing the relationship between nanohardness values ​​and verification irradiation dose in one embodiment of this application;

[0017] Figure 10 This is the second fitting curve in one embodiment of this application;

[0018] Figure 11 This is a comparison diagram of the first fitting curve and the second fitting curve in one embodiment of this application. Detailed Implementation

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0020] As indicated in this application, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0021] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0022] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0023] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0024] The method for screening nuclear-grade aluminum alloys by in-situ ion irradiation according to this application will be described below through specific embodiments.

[0025] refer to Figure 1 The flowchart shown in one embodiment illustrates a method for screening nuclear-grade aluminum alloys by in-situ ion irradiation. This method includes the following steps:

[0026] Step S101: Prepare at least one aluminum alloy to be screened as a TEM sample.

[0027] Specifically, in this step, the aluminum alloy to be screened is thinned to prepare a TEM sample whose microstructure can be observed under a transmission electron microscope (TEM).

[0028] In some embodiments, the aluminum alloys to be screened include three types: Al-2.6Mg, Al-2.6Mg-2.28Si, and Al-2.6Mg-2.98Si, which have different Mg and Si contents. In this embodiment, the numbers preceding the elements in the three aluminum alloys to be screened represent the mass percentage of the corresponding element in the respective alloy. For example, in the Al-2.6Mg-2.98Si aluminum alloy, the mass percentage of Al is 94.42%, the mass percentage of Mg is 2.6%, and the mass percentage of Si is 2.98%.

[0029] In some embodiments, in step S101, an electrolytic double-spray method is used, which employs a specific electrolyte ratio and strictly controlled constant current and temperature to perform double-sided electrolytic polishing on the aluminum alloy to be screened, thereby thinning the aluminum alloy. Different electrolyte compositions and process parameters are selected for aluminum alloys with different compositions. For example, a mixed solution with a volume ratio of perchloric acid:acetic acid:ethanol of 1:8:1 is selected as the electrolyte, and the set process parameters include a constant current of 25mA and a temperature of -5°C, preferably -20°C.

[0030] In some embodiments, before thinning the aluminum alloy to be screened using the electrolytic double-jet method, the aluminum alloy is first processed into a sheet with a diameter of 3 mm and a thickness of approximately 70 μm by mechanical cutting and thinning. For example, the aluminum alloy to be screened is cut using wire electrical discharge machining (EDM), and then thinned using an automatic polishing machine to obtain the sheet for subsequent electrolytic double-jet thinning. This allows for uniform thinning of the aluminum alloy to be screened and facilitates control of the sheet thickness.

[0031] Step S102: Determine at least one in-situ observation region in the TEM sample.

[0032] Specifically, the TEM sample prepared in step S101 is preliminarily characterized using a transmission electron microscope. Microstructural features that are not easily altered are used as markers for the in-situ observation area, thus facilitating rapid location of the in-situ observation area under different irradiation doses and magnifications. These microstructural features that are not easily altered include grain boundaries, precipitates, and intrinsic dislocation lines.

[0033] In some embodiments, preliminary characterization of the TEM sample includes using convergent beam electron diffraction (CBED) to accurately measure the thickness of the thin region of the TEM sample, and using selected area electron diffraction (SAED) to measure the grain orientation of the TEM sample.

[0034] In some embodiments, the in-situ observation region has the following characteristics: (1) The thickness of the in-situ observation region is 100nm~150nm, and the absolute value of the thickness difference of the in-situ observation region between each TEM sample does not exceed 10nm, so as to ensure that the in-situ observation region has sufficient electron beam penetration and reduce the influence of the surface on the defect evolution; (2) The grain orientation of the in-situ observation region is

[011] , which has high symmetry and is conducive to achieving high-quality diffraction imaging; (3) The number of intrinsic dislocation lines in the in-situ observation region under bright field image is small, and there are no obvious corrosion, contamination and stress stripes, so that the newly generated dislocation loops can be clearly observed and analyzed in subsequent in-situ ion irradiation.

[0035] Step S103: In-situ ion irradiation is performed on at least one in-situ observation area under multiple simulated irradiation doses.

[0036] In some embodiments, at least six different simulated irradiation doses are used to irradiate the in-situ observation area. Considering the impact of the sample size and statistical error in the in-situ observation area, at least three in-situ observation areas are selected from the same TEM sample.

[0037] In some embodiments, the dose span of the multiple simulated irradiation doses covers the entire process from the initial formation of a dislocation loop to its evolution into a dislocation network. In other words, the minimum of the multiple simulated irradiation doses is no greater than the irradiation dose at which the dislocation loop begins to form, and the maximum is no less than the irradiation dose at which the dislocation loop evolves into a dislocation network. In other embodiments, the dose span of the multiple simulated irradiation doses covers the initial irradiation dose that causes changes in the in-situ observation area (such as the appearance of point defects or dislocation damage) and the final irradiation dose that saturates the irradiation defects.

[0038] In some embodiments, the irradiation dose at the onset of dislocation loop formation, the irradiation dose at which the dislocation loop evolves into a dislocation network, the initial irradiation dose, and the final irradiation dose for each TEM sample are obtained by consulting relevant literature in the art. In other embodiments, the irradiation dose at the onset of dislocation loop formation, the irradiation dose at which the dislocation loop evolves into a dislocation network, the initial irradiation dose, and the final irradiation dose for each TEM sample are recorded through in-situ ion irradiation experiments. Specifically, each TEM sample is subjected to in-situ ion irradiation at a set temperature (e.g., room temperature) until the internal irradiation defects of each TEM sample are saturated. The irradiation dose at which the changes begin to appear, the irradiation dose at which dislocation loops begin to appear, the irradiation dose at which the dislocation loop evolves into a dislocation network, and the irradiation dose at which the irradiation defects saturate are recorded during the in-situ ion irradiation experiment.

[0039] In some embodiments, at least one in-situ observation area is subjected to in-situ ion irradiation at a temperature of 90°C to 100°C, so that the in-situ ion irradiation conditions reflect the actual reactor service temperature as closely as possible.

[0040] For example, in this step, when the aluminum alloys to be screened include Al-2.6Mg, Al-2.6Mg-2.28Si, and Al-2.6Mg-2.98Si, the irradiation dose for forming dislocation networks in each TEM sample is 3 dPa. At room temperature, using 400 keV Al in a multi-ion beam and transmission electron microscope coupled facility... +In-situ ion irradiation was performed on each TEM sample. At an in-situ ion irradiation energy of 400 keV, the ion range matched the thin film thickness of the transmission electron microscope (TEM), enabling uniform displacement damage in the in-situ observation area, thus facilitating real-time characterization of defect generation and evolution. Seven simulated irradiation doses, ranging from unirradiated to irradiated dislocation networks, were selected for in-situ ion irradiation. These seven simulated irradiation doses, from low to high, were 0 dpa, 0.3 dpa, 0.5 dpa, 1.0 dpa, 1.5 dpa, 2.0 dpa, and 3.0 dpa. During the in-situ ion irradiation process, the in-situ observation area at each simulated irradiation dose was photographed and recorded. In some embodiments, multiple magnifications of the in-situ observation area in positive focus mode were used to capture bright-field images from low to high magnification to reduce the influence of statistical errors.

[0041] refer to Figure 2 The diagram illustrates the evolution of the microstructure of the in-situ observation area with irradiation dose in one embodiment. The aluminum alloy to be screened is Al-2.6Mg, and the simulated irradiation dose is 0.3 dpa (i.e., Figure 2 a) 0.5 dpa (i.e. Figure 2 (b) 1.0 dpa (i.e. Figure 2 c) 1.5 dpa (i.e. Figure 2 d), 2.0dpa (i.e. Figure 2 e), 3.0 dpa (i.e. Figure 2 (f) As can be seen, as the simulated irradiation dose increases, dislocation loops first form within the in-situ observation area, then the number of dislocation loops increases, and finally the dislocation loops evolve into a dislocation network.

[0042] Step S104: Based on the statistical results of dislocation loops in at least one in-situ observation region, calculate multiple first yield strength increments corresponding to multiple simulated irradiation doses for each of the at least one in-situ observation region.

[0043] refer to Figure 3 The flowchart shown in one embodiment illustrates the calculation of the first yield strength increment of the in-situ observation region based on the dislocation loop statistical results. Step S104 includes the following steps:

[0044] Step S201: Statistically calculate the average size and average number density of dislocation loops in at least one in-situ observation region before the dislocation loops evolve into dislocation networks, after irradiation with each simulated irradiation dose.

[0045] Specifically, after being irradiated with a certain irradiation dose, the internal dislocation loops in the in-situ observation area evolve into dislocation networks. Therefore, the average size and average number density of dislocation loops in the in-situ observation area after irradiation with the simulated irradiation dose before the dislocation loops evolve into dislocation networks are statistically analyzed.

[0046] In some embodiments, the average size and average number density of dislocation loops in regions where the intrinsic dislocation density is greater than a first preset density, at grain boundaries, and where precipitates are located are not statistically analyzed to avoid affecting the generality of the statistical data. For example, the first preset density is 2.22 × 10⁻⁶. -8 / nm 3 .

[0047] The formula for calculating the average size of a dislocation ring is: In the formula, The average size of the dislocation loop. For the first statistical The size of a dislocation loop This represents the number of dislocation loops. The average number density of dislocation loops depends on the matrix volume of the in-situ observation region. The formula for calculating the average number density of dislocation loops is: In the formula, The average number density of dislocation loops. To count the number of dislocation loops. The area of ​​the in-situ observation region perpendicular to the thickness is denoted as . The actual thickness of the in-situ observation region. In some embodiments, the actual thickness of the in-situ observation region is accurately measured by convergent beam electron diffraction. This measurement method is not the focus of this application and will not be described in detail.

[0048] In some embodiments, the specific steps for statistically analyzing the average size and average number density of dislocation loops are as follows. First, the contrast characteristics of dislocation loops within the in-situ observation region are identified in the TEM bright-field image. Identification is based on contrast characteristics, which include deep contrast and hollow internal defect morphologies, while non-contrast characteristics include morphologies with blurred edges or solid internal structures. Then, the dislocation loops conforming to the contrast characteristics are outlined (e.g.,...). Figure 4 As shown in the image, subsequent data only include dislocation loops that meet the contrast characteristics. Then, using ImageJ software, the scale was set according to the image ruler, the in-situ observation area was selected and its planar area was obtained. The major axis diameter of each dislocation loop that meets the contrast characteristics was measured, and the size of the dislocation loops was calculated. For irregular dislocation loops, the length of the longest axis was measured as the major axis diameter. Finally, the average size and average number density of the dislocation loops were calculated.

[0049] In some embodiments, the number of dislocation loops included in the statistics is no less than 50.

[0050] For example, the aluminum alloys to be screened include Al-2.6Mg, Al-2.6Mg-2.28Si, and Al-2.6Mg-2.98Si. After irradiation with a dose of 0.3 dPa, dislocation loops in these three alloys begin to nucleate, while after irradiation with a dose of 2.0 dPa, the dislocation loops form a dislocation network structure that cannot be statistically analyzed. Therefore, the average size and average number density of dislocation loops in the in-situ observation region after irradiation with simulated doses of 0.5 dPa, 1.0 dPa, 1.5 dPa, and 2.0 dPa are statistically analyzed.

[0051] refer to Figure 5 The line graph showing the statistical average size of dislocation loops, and Figure 6 The line graph shown represents the statistical mean number density of dislocation loops. The horizontal axis represents the radiation dose in dPa. Figure 5 The vertical axis represents the average size in nm. Figure 6 The vertical axis represents the mean number density in units of 10. 22 / m 3 .exist Figure 5 In the diagram, the horizontal axis represents the simulated irradiation dose before the dislocation loop evolves into a dislocation network, and the vertical axis represents the discrete points of the average size of the dislocation loop after irradiation with the corresponding simulated irradiation dose in the in-situ observation area. These discrete points are connected by line segments. It can be seen that the average size of the dislocation loop gradually increases with increasing simulated irradiation dose. Figure 6 In the figure, the horizontal axis represents the simulated irradiation dose before the dislocation loops evolve into dislocation networks, and the vertical axis represents the discrete points of the average number density of the dislocation loops after irradiation with the corresponding simulated irradiation dose in the in-situ observation area. These discrete points are connected by line segments. It can be seen that as the simulated irradiation dose increases, the average number density of the dislocation loops in Al-2.6Mg aluminum alloy (corresponding to 2.6Mg in the figure) and Al-2.6Mg-2.28Si aluminum alloy (corresponding to 2.6Mg-2.28Si in the figure) first increases and then decreases. The average number density of the dislocation loops in Al-2.6Mg-2.98Si aluminum alloy (corresponding to 2.6Mg-2.98Si in the figure) changes in the following order: decreasing, increasing, and decreasing.

[0052] Step S202: Based on the average size and average number density of dislocation loops, calculate multiple first yield strength increments corresponding to multiple simulated irradiation doses according to the irradiation hardening model.

[0053] In some embodiments, the calculation formula for the irradiation hardening model is: In the formula, This is the first yield strength increment. These are constants related to materials mechanics. For Burgers vectors, The average number density of dislocation loops. The average size of the dislocation loop is given. In this step, based on the average size and average number density of the dislocation loop obtained in step S201, the first yield strength increment corresponding to each simulated irradiation dose is calculated according to the calculation formula of the irradiation hardening model.

[0054] Step S105: Select the core aluminum alloy based on multiple first yield strength increments.

[0055] Specifically, the yield strength increment of aluminum alloy materials reflects their radiation resistance. Under the same irradiation dose, the aluminum alloy with the lowest yield strength increment should be selected. In this step, based on the comparison results of the first yield strength increment of multiple aluminum alloys to be screened under the same simulated irradiation dose, the aluminum alloy with the smallest first yield strength increment is selected as the nuclear-grade aluminum alloy.

[0056] In one embodiment, step S104 calculates the first yield strength increment of the in-situ observation region of three aluminum alloys to be screened (Al-2.6Mg aluminum alloy, Al-2.6Mg-2.28Si aluminum alloy, and Al-2.6Mg-2.98Si aluminum alloy) at four simulated irradiation doses of 0.5 dPa, 1.0 dPa, 1.5 dPa, and 2.0 dPa. Among them, the first yield strength increment of the in-situ observation region of Al-2.6Mg-2.98Si aluminum alloy is the smallest after irradiation at a simulated irradiation dose of 2.0 dPa. Therefore, when screening for nuclear-grade aluminum alloys based on an irradiation dose of 2.0 dPa, Al-2.6Mg-2.98Si aluminum alloy, which has the smallest first yield strength increment at 2 dPa, is selected as the nuclear-grade aluminum alloy.

[0057] In some embodiments, a line graph representing the relationship between the simulated irradiation dose and the first yield strength increment is plotted. Specifically, in a coordinate system where the horizontal and vertical axes represent the simulated irradiation dose and the first yield strength increment, respectively, discrete points of the simulated irradiation dose and the corresponding first yield strength increment are plotted, and these discrete points are connected sequentially by line segments. If a nuclear-grade aluminum alloy with an actual irradiation dose of 1.7 dPa is selected, the first yield strength increment at an irradiation dose of 1.7 dPa is calculated based on simulated irradiation doses of 1.5 dPa and 2.0 dPa and their corresponding first yield strength increments, using interpolation methods (such as linear interpolation, Lagrange interpolation, etc.). The Al-2.6Mg-2.98Si aluminum alloy with the smallest first yield strength increment is then selected as the nuclear-grade aluminum alloy.

[0058] In other embodiments, the method for screening nuclear-grade aluminum alloys by in-situ ion irradiation proposed in this application further includes: fitting multiple simulated irradiation doses and multiple first yield strength increments using a power-law model to obtain a first fitting curve describing the relationship between the simulated irradiation dose and the first yield strength increment. Specifically, a power-law model is used to fit the mapping relationship between the simulated irradiation dose and the corresponding first yield strength increment, that is, any simulated irradiation dose can be used to obtain a corresponding first yield strength increment through the power-law model, and the expression of this mapping relationship is the first fitting curve describing the relationship between the simulated irradiation dose and the first yield strength increment. For example, the power-law model is: In the formula, The yield strength increment of the aluminum alloy to be screened after irradiation. Let be the initial yield strength of the first fitted curve. This is the irradiation dose. and These are the fitting parameters.

[0059] In this embodiment, the step of screening nuclear-grade aluminum alloys based on multiple first yield strength increments includes: screening aluminum alloys that meet the requirements based on a first fitting curve. Specifically, for the actual irradiation dose, the aluminum alloy with the smallest first yield strength increment corresponding to each aluminum alloy to be screened, calculated using the first fitting curve, is selected as the nuclear-grade aluminum alloy.

[0060] refer to Figure 7 The first fitted curve in one embodiment shown has the horizontal axis representing the irradiation dose in dPa and the vertical axis representing the first yield strength increment in MPa. For example... Figure 7 As shown, the Al-2.6Mg-2.98Si aluminum alloy (corresponding to 2.6Mg-2.98Si in the legend) has the smallest increase in the first yield strength corresponding to each irradiation dose, so Al-2.6Mg-2.98Si aluminum alloy is selected as the aluminum alloy for nuclear applications.

[0061] It should be noted that, in order to verify the accuracy and reliability of screening nuclear aluminum alloys by in-situ ion irradiation, in some embodiments, the method for screening nuclear aluminum alloys by in-situ ion irradiation also includes a verification step.

[0062] refer to Figure 8 The flowchart shown in one embodiment illustrates the process for verifying the accuracy of the method for screening aluminum alloys. The verification steps include:

[0063] Step S301: Use a power-law model to fit multiple simulated irradiation doses and multiple first yield strength increments to obtain first fitting parameters describing the relationship between simulated irradiation doses and first yield strength increments.

[0064] In this step, a power-law model is used to fit the mapping relationship between the simulated irradiation dose and the corresponding first yield strength increment, resulting in ( , The parameter combination is the first fitting parameter. Furthermore, for the irradiation dose that has not been actually measured, a set of determined first fitting parameters ( , It can calculate the corresponding first yield strength increment.

[0065] Step S302: Measure multiple nanohardness values ​​of the aluminum alloy to be screened corresponding to multiple verification irradiation doses, and convert the multiple nanohardness values ​​into multiple corresponding second yield strength increments.

[0066] In some embodiments, 1.35 MeV ions are used to conduct out-of-situ irradiation experiments on the aluminum alloys to be screened. The experiments include multiple verification irradiation doses, and nanoindentation tests are performed on the aluminum alloys to be screened after each verification irradiation dose. The range of 1.35 MeV ions can cover a depth of several micrometers in the aluminum alloy, which can accelerate the simulation of displacement damage caused by in-reactor neutron irradiation at the laboratory scale. Therefore, it can be used to evaluate the radiation resistance of aluminum alloy materials under near-reactor service conditions. In some embodiments, the high-energy out-of-situ irradiation experiment is conducted at 100°C. In some embodiments, Si with an energy of 1.35 MeV is selected. 5+ Conduct out-of-situ irradiation experiments.

[0067] In some embodiments, multiple irradiation doses consistent with the simulated irradiation dose are selected as validation irradiation doses. For example, the validation irradiation doses are 0.5 dpa, 1.0 dpa, 1.5 dpa, and 2.0 dpa.

[0068] Hardness depth curves corresponding to multiple verification irradiation doses were obtained by nanoindentation testing. The average value of these curves was taken, and the nanohardness value corresponding to each aluminum alloy to be screened and each verification irradiation dose was calculated using the Nix-Gao model.

[0069] refer to Figure 9 The line graph shown in one embodiment illustrates the relationship between nanohardness values ​​and the verification irradiation dose. The horizontal axis represents the irradiation dose in dPa, and the vertical axis represents the nanohardness value in GPa. It can be seen that the nanohardness value of Al-2.6Mg aluminum alloy increases, decreases, and then increases again with increasing verification irradiation dose; the nanohardness value of Al-2.6Mg-2.28Si aluminum alloy increases with increasing verification irradiation dose; and the nanohardness value of Al-2.6Mg-2.98Si aluminum alloy decreases first and then increases with increasing verification irradiation dose.

[0070] Subsequently, the nanohardness value is converted into the corresponding second yield strength increment according to an empirical formula. In some embodiments, the empirical formula is: In the formula, This is the converted second yield strength increment. This represents the nanoscale hardness value.

[0071] Step S303: Use a power-law model to fit multiple verification irradiation doses and multiple second yield strength increments to obtain a second fitting parameter describing the relationship between the verification irradiation dose and the second yield strength increment.

[0072] In this step, a power-law model is used to fit and verify the mapping relationship between the irradiation dose and the corresponding second yield strength increment, resulting in a second fitted curve. , The parameter combination is the second fitting parameter. Furthermore, for the irradiation dose that has not been actually measured, a set of determined second fitting parameters ( , It can calculate the corresponding second yield strength increment.

[0073] refer to Figure 10 The second fitting curve shown in one embodiment is plotted based on the second fitting parameters that describe and verify the relationship between the irradiation dose and the second yield strength increment. The horizontal axis represents the irradiation dose in dpa, and the vertical axis represents the second yield strength increment in MPa.

[0074] Step S304: Based on the comparison results of the first fitting parameters and the second fitting parameters, determine the accuracy of the method of screening nuclear aluminum alloys by in-situ ion irradiation.

[0075] refer to Figure 11 The comparison graph of the first and second fitted curves is shown. The horizontal axis represents the irradiation dose in dPa, and the vertical axis represents the yield strength increment in MPa. The first fitted curves for the three aluminum alloy samples to be screened only fit the irradiation dose and the corresponding first yield strength increment before the dislocation loops form a dislocation network. Figure 11 As shown, the first and second fitting curves of each sample to be screened exhibit good consistency in their trends, and the magnitudes of the yield strength increments of each sample remain consistent. The comparison results of the first and second fitting parameters are shown in Table 1. For the same aluminum alloy to be screened, the first and second fitting parameters show a high degree of agreement. These results demonstrate that the method of calculating the first yield strength increment by in-situ ion irradiation to screen core aluminum alloys has reliable accuracy.

[0076] Table 1: Comparison of the first and second fitting parameters

[0077] aluminum alloys to be screened First fitting parameters Second fitting parameters Al-2.6Mg aluminum alloy （41.2, 0.52） （39.8, 0.56） Al-2.6Mg-2.28Si aluminum alloy （32.5, 0.41） （31.5, 0.39） Al-2.6Mg-2.98Si aluminum alloy （34.6, 0.40） （36.8, 0.44）

[0078] This application also proposes a nuclear-grade aluminum alloy, which is obtained by screening using the screening method described above.

[0079] This application uses specific terms to describe embodiments of the application. Terms such as "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0080] It should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0081] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used to describe embodiments are sometimes modified by the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in this application are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

Claims

1. A method of screening nuclear grade aluminum alloys by in-situ ion irradiation, characterized by, The method comprises the following steps: preparing at least one aluminum alloy to be screened into a TEM sample; determining at least one in-situ observation area in the TEM sample; carrying out in-situ ion irradiation on the at least one in-situ observation area under a plurality of simulated irradiation doses; calculating a plurality of first yield strength increments corresponding to the plurality of simulated irradiation doses respectively according to the statistical results of dislocation loops in the at least one in-situ observation area; and screening the nuclear aluminum alloy according to the plurality of first yield strength increments.

2. The method of screening nuclear-use aluminum alloys by in-situ ion irradiation according to claim 1, wherein, The step of calculating a plurality of first yield strength increments corresponding to the plurality of simulated irradiation doses respectively according to the statistical results of dislocation loops in the at least one in-situ observation area comprises: counting the average size and average number density of the dislocation loops in the at least one in-situ observation area after being irradiated by each simulated irradiation dose before the dislocation loops evolve into dislocation networks; calculating the plurality of first yield strength increments corresponding to the plurality of simulated irradiation doses respectively according to an irradiation hardening model based on the average size and average number density of the dislocation loops.

3. The method of screening nuclear grade aluminum alloys by in situ ion irradiation as claimed in claim 2, wherein, The average size and average number density of the dislocation loops at regions with an intrinsic dislocation density greater than a first preset density, grain boundaries and precipitates are not counted.

4. The method of screening nuclear-use aluminum alloys by in-situ ion irradiation according to claim 1, wherein The dose span of the plurality of simulated irradiation doses covers the entire process from the initial generation of the dislocation loops to the evolution into dislocation networks.

5. The method of screening nuclear grade aluminum alloys by in situ ion irradiation as claimed in claim 1, wherein, The step of screening the nuclear aluminum alloy according to the plurality of first yield strength increments comprises screening the aluminum alloy to be screened with the smallest first yield strength increment according to the comparison results of the first yield strength increments of a plurality of the aluminum alloys to be screened under the same simulated irradiation dose.

6. The method of screening nuclear-use aluminum alloys by in-situ ion irradiation according to claim 1, wherein The method further comprises the following steps: fitting the plurality of simulated irradiation doses and the plurality of first yield strength increments using a power law model to obtain a first fitting curve describing the relationship between the simulated irradiation doses and the first yield strength increments, wherein the step of screening the nuclear aluminum alloy according to the plurality of first yield strength increments comprises screening the aluminum alloy to be screened that meets the requirements based on the first fitting curve.

7. The method of screening nuclear-use aluminum alloys by in-situ ion irradiation according to claim 1, wherein The method further comprises the following verification steps: fitting the plurality of simulated irradiation doses and the plurality of first yield strength increments using a power law model to obtain a first fitting parameter describing the relationship between the simulated irradiation doses and the first yield strength increments; measuring a plurality of nano-hardness values corresponding to a plurality of verification irradiation doses respectively of the aluminum alloy to be screened, and converting the plurality of nano-hardness values into a plurality of second yield strength increments respectively; fitting the plurality of verification irradiation doses and the plurality of second yield strength increments using the power law model to obtain a second fitting parameter describing the relationship between the verification irradiation doses and the second yield strength increments; judging the accuracy of the method of screening the nuclear aluminum alloy by in-situ ion irradiation according to the comparison results of the first fitting parameter and the second fitting parameter.

8. The method of screening nuclear grade aluminum alloys by in situ ion irradiation as claimed in claim 1, wherein, The in-situ ion irradiation on the at least one in-situ observation area is carried out at a temperature of 90-100°C.

9. The method of screening nuclear grade aluminum alloys by in situ ion irradiation as claimed in claim 1, wherein, The in-situ ion irradiation uses aluminum ions.

10. An aluminum alloy for nuclear use, characterized by comprising, in mass %, The nuclear use aluminum alloy is screened by the method for screening a nuclear use aluminum alloy by in-situ ion irradiation according to any one of claims 1 to 9. The nuclear use aluminum alloy is screened by the method for screening a nuclear use aluminum alloy by in-situ ion irradiation according to any one of claims 1 to 9.

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