Preparation method of Mg / Al laminated material interface irradiation damage behavior analysis sample

Abstract

The invention discloses a preparation method of an Mg / Al laminated material interface irradiation damage behavior analysis sample, which comprises the following steps: respectively calculating the incidence depths of Mg < + > with different energies in an Mg / Al laminated material by adopting SRI < M > software, and calculating the irradiation damage layer depth of incident ions with specific energy; performing ion beam cutting on the ion irradiation sample according to the SRI M calculation result; sequentially selecting ion beams with different beam sizes to thin the cut interface sample; by adjusting parameters such as the electrolytic polishing solution ratio, the polishing temperature, the polishing time and the polishing voltage, the optimal rapid polishing process parameters of the Mg / Al laminated material interface sample are explored; according to the method, by means of combination of SRI M software simulation, ion beam micro-nano scale processing, a differential thinning process, rapid polishing treatment and the like, preparation of the Mg / Al interface transmission electron microscope sample in the Mg / Al laminated material after ion irradiation can be effectively completed, and Mg / Al interface irradiation damage behavior analysis and rapid screening of the high-performance Mg / A laminated material are achieved.

Description

Technical Field

[0001] The present invention relates to the study of nuclear fuel cycle and radiation effect. Background Art

[0002] After the U.S. Department of Energy launched the "De-enrichment Program", UMo / Al fuel is considered to be the mainstream development direction of fuel elements for research reactors worldwide due to its high uranium loading and good service performance. However, with the increase in service temperature and burnup, UMo / Al fuel still faces failure risks such as pillow deformation and blistering failure caused by irradiation swelling and reduced thermal conductivity, which seriously affects the safety of reactor operation.

[0003] To solve this problem, researchers tried to replace Al with a magnesium (Mg) matrix that does not react with U or Mo, thus forming UMo / Mg / Al fuel, which is recognized as the most promising solution. Although many off-pile research results have shown that UMo / Mg / Al fuel exhibits good mechanical and thermal properties, after being damaged by high-dose fast neutron irradiation, it is not yet known whether UMo / Mg / Al fuel, especially the Mg / Al laminated material used as fuel cladding, can still maintain good interface bonding, high temperature strength, and radiation swelling resistance without significantly affecting its neutron economy and thermal conductivity. Therefore, screening a Mg / Al laminated cladding material with excellent comprehensive performance is the primary problem that needs to be solved in this field.

[0004] Under the action of neutron irradiation, Mg / Al laminated materials will produce a large number of irradiation defects, thus affecting their thermal / mechanical properties. Since reactor neutron irradiation has the characteristics of high cost, long cycle, and many interference factors (wide neutron energy spectrum, uneven temperature distribution), it is not conducive to the screening of Mg / Al laminated materials and the study of their irradiation damage behavior. Ion irradiation, because its initial process of producing atomic displacement is very similar to neutron irradiation, has many advantages such as single stable energy, controllable temperature, low experimental cost, short cycle, and basically no radioactivity. Therefore, ion irradiation is widely used internationally to simulate the neutron irradiation damage behavior of materials. However, ion irradiation is affected by electron energy loss, and the irradiation depth is mostly shallow, only on the order of μm. Therefore, how to realize the preparation of Mg / Al interface transmission electron microscope samples in Mg / Al laminated materials after ion irradiation is the key link to carry out the analysis of Mg / Al interface irradiation damage behavior and the rapid screening of high-performance Mg / Al laminated materials. However, there are currently no reports on sample preparation methods for analyzing irradiation damage behavior of Mg / Al interfaces. In view of the above situation, it is necessary to propose an effective sample preparation method. Summary of the invention

[0005] In order to solve the existing problems, the purpose of the present invention is to provide a method for preparing samples for analyzing the radiation damage behavior of Mg / Al laminated materials, which is mainly used to effectively complete the preparation of transmission electron microscopy samples of Mg / Al interface in Mg / Al laminated materials after ion irradiation, so as to realize the analysis of Mg / Al interface radiation damage behavior and the rapid screening of high-performance Mg / Al laminated materials.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows.

[0007] A method for preparing a sample for analyzing the radiation damage behavior of a Mg / Al laminated material interface is provided. The method combines software simulation, ion beam micro-nanoscale processing, differential thinning and "quick polishing" processing to prepare a sample for analyzing the radiation damage behavior of a Mg / Al laminated material interface after ion irradiation. The method comprises the following steps:

[0008] Step 1, SRIM calculation: SRIM simulation software is used to calculate the incident depth of incident ions of different energies in the Mg / Al stacked material, and the depth of the irradiation damage layer of incident ions of specific energy is calculated;

[0009] Step 2, ion beam cutting: According to the results of SRIM calculation, electron beam and ion beam deposition are performed perpendicular to the Mg / Al interface using a focused ion beam scanning electron microscope (FIB), and ion beam cutting is performed along the irradiation depth direction. The cutting depth is about 2 to 3 times the SRIM calculation result;

[0010] Step 3, ion beam thinning: select ion beams with different beam currents to thin the cut interface samples in turn. Due to the different hardnesses of Al alloy and Mg alloy, the thinning time of the Al alloy area needs to be extended or the ion beam current needs to be increased during the thinning process until the electron beam can easily penetrate the area to be observed near the interface, the interface remains intact, and the sample does not undergo obvious deformation;

[0011] Step 4. Exploration of the "quick polishing" process for non-irradiated samples: Cut and thin the non-irradiated Mg / Al laminated material interface samples by referring to the ion beam cutting and thinning processes in steps 2 and 3, and use an electrolytic polishing and corrosion device to perform "quick polishing" on the non-irradiated Mg / Al laminated material interface samples after recrystallization annealing, with the elimination of the ion damage layer introduced by the Ga ion beam of the FIB as the standard, and explore the "quick polishing" process parameters of the Mg / Al laminated material interface samples;

[0012] Step 5: "Rapid polishing" treatment of ion irradiated samples: the "rapid polishing" process of the interface sample of the non-irradiated Mg / Al stacked material after recrystallization annealing is used to perform "rapid polishing" treatment on the sample after ion beam thinning to eliminate the ion damage layer introduced by the Ga ion beam during the thinning process;

[0013] Step 6: TEM characterization: After the "rapid casting" is completed, the bright and dark field images of the sample are observed using a transmission electron microscope. If irradiation defects can be observed and there are no obvious ion beam processing stripes and deformations in the sample, the sample preparation is completed.

[0014] Based on the technical solution provided by the present invention, the melting point (T m ) The maximum temperature is about 660℃, and the recrystallization temperature is about 0.4T m , that is, the recrystallization annealing temperature is 264°C;

[0015] Further optimization of the above technical solution, the "fast polishing" treatment of the interface sample of the Mg / Al stacked material refers to the use of the principle of electrolytic polishing to quickly polish the TEM sample prepared by FIB. Different from conventional electrolytic polishing, the sample polished by electron microscope is usually a diameter of The polishing time for a wafer ranges from more than ten seconds to hundreds of seconds; while the TEM sample prepared by FIB is only about 10μm×20μm. If the polishing efficiency is too high or the time is too long, the sample will be easily damaged. Therefore, the polishing voltage of the "speed polishing" process is only 10V, and the polishing time is only a few tenths of a second.

[0016] The polishing liquid used for "speed polishing" treatment is 8% to 10% perchloric acid + 90% to 92% alcohol solution, the "speed polishing" voltage is between 10V and 12V, the "speed polishing" temperature is between -40℃ and -35℃, and the "speed polishing" time is between 0.05s and 0.3s.

[0017] Further optimization and improvement, the incident ion is Mg + For ions, the energy range calculated by SRIM software is 10keV~10MeV.

[0018] Further optimization and improvement, the specific energy is 1.5MeV, the depth of the irradiated damaged layer is between 1500nm and 3000nm, and the peak depth is about 2250nm.

[0019] According to further optimization and improvement, the ion beam cutting depth is 8 μm to 10 μm and the width is 15 μm to 20 μm.

[0020] Further optimization and improvement, the ion beam parameters of different beam current sizes are between 5kV and 30kV, 44pA and 0.44nA, the single-side single thinning time is 10s to 2min, and the beam current size and thinning time are adjusted according to the actual situation of sample thinning.

[0021] Compared with the prior art, the technical effect achieved by the present invention is that: a method for preparing samples for analyzing the irradiation damage behavior of the interface of Mg / Al laminated materials is provided, and by combining SRIM software simulation, ion beam micro-nanoscale processing, differentiated thinning process and "quick polishing" treatment and other means, the preparation of transmission electron microscope samples of the Mg / Al interface in the Mg / Al laminated material after ion irradiation can be effectively completed, so as to realize the analysis of the irradiation damage behavior of the Mg / Al interface and the rapid screening of high-performance Mg / Al laminated materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1.5MeV Mg + SRIM simulation results of ion-irradiated Mg alloy.

[0023] Figure 2 Schematic diagram of ion beam cutting perpendicular to the Mg / Al interface using FIB. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1 , Figure 2 As shown, a method for preparing a sample for analyzing the radiation damage behavior of a Mg / Al laminated material interface comprises the following steps:

[0026] Step 1: Use the “Ion Distribution and Quick Calculation of Damage” function of the Stopping and Range of Ions into Matter (SRIM) software to calculate the Mg content at different energies (10keV-10MeV). + The incident depth at the interface of Mg / Al stacked materials, combined with Mg + The beam yield was calculated by selecting an appropriate injection energy (1.5 MeV) to obtain the data on the distribution of irradiated defect (vacancy) concentration with depth. Then, the calculation formula between the dislocation per atom (dpa) and the irradiated defect concentration was used to construct the Mg ions at 1.5 MeV injection energy. + The relationship between ion beam irradiation damage (dpa)-irradiation depth-ion concentration is obtained to obtain the Mg under 1.5MeV implantation energy. + Depth of irradiation damage layer at the interface of Mg / Al stacked materials;

[0027] Step 2: Align the irradiated surface of the Mg / Al interface sample with the Ga ion beam of the FIB, select a certain area in the direction perpendicular to the Mg / Al interface for electron beam and ion beam deposition in turn to avoid damage to the sample in the area during ion beam cutting, and perform ion beam cutting along the direction of ion beam irradiation. The cutting method is to dig a "V" groove on both sides and then cut it in a "U" shape. In addition, according to the results of SRIM calculation, 1.5MeVMg + The peak depth of the radiation damage layer at the interface of the Mg / Al stacked material is about 2250nm. In order to reduce the impact of the radiation damage layer during ion beam cutting, the cutting depth is controlled between 8μm and 10μm.

[0028] Step 3: Use the nanomanipulator that comes with the FIB to extract the "U"-cut sample and weld it to the half-loaded copper mesh, and select parameters such as 30kV@0.44nA, 30kV@90pA, 5kV@63pA, and 5kV@44pA to thin the interface sample after cutting. During the thinning process, the front and back sides of the sample should be thinned alternately, and because the hardness of Al alloy is greater than that of Mg alloy, when thinning on the same side, the thinning time close to the Al alloy side should be longer or the beam current should be larger to ensure that the matrix on both sides of the Mg / Al interface can be thinned to a similar thickness at the same time. At the same time, in order to avoid uneven thickness on both sides of the interface causing the sample to curl and deform, the thinning area must be gradually reduced and the interface and both sides of the interface must be thinned alternately until the electron beam can easily penetrate the area to be observed near the interface, the interface remains intact, and the sample has no obvious deformation;

[0029] Step 4: Cut and thin the interface sample of the non-irradiated Mg / Al laminated material by referring to the ion beam cutting and thinning process in steps 2 and 3, prepare the electrolyte required for the "quick polishing" treatment, and connect the electrodes, power supply, timer and recrystallization annealed non-irradiated Mg / Al laminated material interface sample of the electrolytic polishing corrosion device, and find the best "quick polishing" process parameters of the Mg / Al laminated material interface sample by adjusting the electrolytic polishing liquid ratio, polishing temperature, polishing time, polishing voltage and other parameters;

[0030] Step 5: After ion cutting and thinning of the Mg / Al stacked material interface sample after ion irradiation, it is connected to the electrodes, timer and power supply of the electrolytic polishing and etching device, and subjected to "fast polishing" treatment using the best "fast polishing" process parameters explored in advance to eliminate the ion damage layer introduced by the Ga ion beam during the thinning process;

[0031] Step 6: Place the sample after the "quick throw" treatment into the transmission electron microscope, draw the vacuum, adjust the acceleration voltage of the transmission electron microscope, the electron beam spot size, the area of ​​the sample and the crystal axis, observe the bright and dark field images of the sample, confirm that there are no obvious traces of ion beam processing in the sample, no obvious deformation, and the morphology of the irradiation defects can be clearly observed, then the sample preparation is completed.

[0032] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several modifications and improvements can be made without departing from the principles and core ideas of the patent of the present invention. These modifications and improvements are also considered to be within the scope of protection of the patent of the present invention.

Claims

1. A method for preparing a sample for analyzing the radiation damage behavior of a Mg / Al laminated material interface, comprising the following steps: Step 1, SRIM calculation: SRIM simulation software is used to calculate the incident depth of incident ions of different energies in the Mg / Al stacked material, and the depth of the irradiation damage layer of incident ions of specific energy is calculated; Step 2, ion beam cutting: According to the results of SRIM calculation, electron beam and ion beam deposition are performed perpendicular to the Mg / Al interface using a focused ion beam scanning electron microscope (FIB), and ion beam cutting is performed along the irradiation depth direction. The cutting depth is about 2 to 3 times the SRIM calculation result; Step 3, ion beam thinning: select ion beams with different beam currents to thin the cut interface samples in turn. Due to the different hardnesses of Al alloy and Mg alloy, the thinning time of the Al alloy area needs to be extended or the ion beam current needs to be increased during the thinning process until the electron beam can easily penetrate the area to be observed near the interface, the interface remains intact, and the sample does not undergo obvious deformation; Step 4. Exploration of the "quick polishing" process for non-irradiated samples: Cut and thin the non-irradiated Mg / Al laminated material interface samples by referring to the ion beam cutting and thinning processes in steps 2 and 3, and use an electrolytic polishing and etching device to perform "quick polishing" on the non-irradiated Mg / Al laminated material interface samples after recrystallization annealing, with the elimination of the ion damage layer introduced by the Ga ion beam of the FIB as the standard, and explore the "quick polishing" process parameters of the Mg / Al laminated material interface samples; Step 5: "Rapid polishing" treatment of ion irradiated samples: Use the "rapid polishing" process of the interface sample of the non-irradiated Mg / Al stacked material after recrystallization annealing to perform "rapid polishing" treatment on the sample after ion beam thinning to eliminate the ion damage layer introduced by the Ga ion beam during the thinning process; Step 6, TEM characterization: After the "rapid casting" is completed, the bright and dark field images of the sample are observed using a transmission electron microscope. If irradiation defects can be observed and there are no obvious ion beam processing stripes and deformations in the sample, the sample preparation is completed.

2. A method for preparing a sample for analyzing radiation damage behavior of a Mg / Al laminated material interface according to claim 1, characterized in that: The melting point of Mg / Al alloy (T m ) The maximum temperature is about 660℃, and the recrystallization temperature is about 0.4T m , that is, the recrystallization annealing temperature is 264°C.

3. A method for preparing a sample for analyzing irradiation damage behavior of a Mg / Al laminated material interface according to claim 1, characterized in that: The polishing liquid used for "speed polishing" treatment is 8%~10% perchloric acid + 90%~92% alcohol solution.

4. A method for preparing a sample for analyzing irradiation damage behavior of a Mg / Al laminated material interface according to claim 3, characterized in that: The "quick throw" voltage is between 10V and 12V, and the "quick throw" temperature is between -40℃ and -35℃.

5. A method for preparing a sample for analyzing radiation damage behavior of a Mg / Al laminated material interface according to claim 4, characterized in that: The "quick throwing" time is between 0.05s and 0.3s.

6. A method for preparing a sample for analyzing irradiation damage behavior of a Mg / Al laminated material interface according to claim 1, characterized in that: The incident ion is Mg + For ions, the energy range calculated by SRIM software is 10keV~10MeV.

7. A method for preparing a sample for analyzing radiation damage behavior of a Mg / Al laminated material interface according to claim 1, characterized in that: The specific energy is 1.5 MeV, the depth of the irradiated damaged layer is between 1500 nm and 3000 nm, and the peak depth is about 2250 nm.

8. A method for preparing a sample for analyzing radiation damage behavior of a Mg / Al laminated material interface according to claim 1, characterized in that: The ion beam cutting depth is 8 μm to 10 μm, and the width is 15 μm to 20 μm.

9. A method for preparing a sample for analyzing radiation damage behavior of a Mg / Al laminated material interface according to claim 1, characterized in that: The ion beam parameters of the different beam current sizes are between 5kV and 30kV, 44pA and 0.44nA, and the single-side single thinning time is 10s to 2min. The beam current size and thinning time are adjusted according to the actual thinning conditions of the sample.

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