A method for evaluating irradiation embrittlement of metal materials based on surface thermal conductivity

Abstract

This invention discloses a method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity, comprising the following steps: S1, irradiating the metal sample to be tested, establishing an irradiation damage amount-damage depth curve, and obtaining the maximum irradiation damage depth; S2, measuring the nanohardness of unirradiated metal samples and irradiated metal samples with different irradiation damage amounts; S3, determining the test laser frequency, and measuring the surface thermal conductivity of unirradiated metal samples and irradiated metal samples with different irradiation damage amounts; S4, establishing a nanohardness-surface thermal conductivity curve; S5, based on the test laser frequency, measuring the surface thermal conductivity of the metal sample to be tested after irradiation, and determining the nanohardness of the metal sample to be tested after irradiation; S6, calculating the ductile-brittle transition temperature increment of the metal sample to be tested after irradiation. This invention effectively evaluates the irradiation embrittlement level of metallic materials through non-destructive measurement of the surface thermal conductivity, and has the advantages of being non-destructive, remote, and capable of real-time detection.

Description

Technical Field

[0001] This invention relates to the field of metal material evaluation technology, and in particular to a method for evaluating the irradiation embrittlement of metal materials based on surface thermal conductivity. Background Technology

[0002] Metallic materials operating in irradiated environments (such as reactors and accelerators) often exhibit irradiation embrittlement due to the formation of irradiation defects, leading to reduced toughness and increased likelihood of fracture failure. Assessing irradiation embrittlement in metallic materials is a crucial requirement for evaluating the service performance of components. Irradiation embrittlement is typically characterized by the ductile-brittle transition temperature increment ΔT, reflecting the degree of irradiation embrittlement and serving as a key indicator with significant engineering implications. For example, in nuclear power plant reactor pressure vessels, a large ΔT value after irradiation may exceed the limits specified in technical specifications, causing the safety of the corresponding components to fail to meet standard requirements.

[0003] Typically, the ΔT value of irradiated metallic materials is obtained using the Charpy impact test. However, there are significant limitations to using the Charpy impact test to assess irradiation embrittlement: 1) The Charpy impact test requires a large sample size and is a destructive test, which may lead to insufficient evaluation samples when test materials are limited; 2) The Charpy impact test is an offline test. In specific engineering evaluations, the component being evaluated may not be able to be cut and sampled, and can only be tested using simulated samples in similar service environments, which may result in the evaluation results not accurately reflecting the actual engineering component; 3) In some special applications (such as irradiated environments, vacuum environments, liquid environments, etc.), it is not possible to continuously monitor the level of irradiation embrittlement of metallic materials remotely. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity, which includes the following steps:

[0006] S1. Irradiate the metal sample to be tested, establish the irradiation damage amount-damage depth curve, and obtain the maximum irradiation damage depth.

[0007] S2. Measure the nanohardness of unirradiated metal samples and irradiated metal samples with different irradiation damage amounts.

[0008] S3. Determine the test laser frequency and measure the surface thermal conductivity of unirradiated metal samples and irradiated metal samples with different irradiation damage amounts.

[0009] S4. Based on the measurement results of steps S2 and S3, establish the nanohardness-surface thermal conductivity curve;

[0010] S5. Based on the test laser frequency, measure the surface thermal conductivity of the metal sample after irradiation, and determine the nanohardness of the metal sample after irradiation according to the nanohardness-surface thermal conductivity curve.

[0011] S6. Based on the nanohardness of the metal sample to be tested after irradiation and the nanohardness of the unirradiated metal sample, calculate the ductile-brittle transition temperature increment of the metal sample to be tested after irradiation to evaluate the irradiation embrittlement level of the metal material.

[0012] In some embodiments, in step S1, the irradiation is proton irradiation, heavy ion irradiation, or neutron irradiation, and the irradiation energy is 220 keV to 260 keV; and / or,

[0013] Based on the elements with a mass percentage ≥ 5% in the metal sample to be tested, the irradiation damage amount-damage depth curve of the metal sample to be tested after irradiation is calculated.

[0014] In some embodiments, in step S2, the maximum irradiation damage depth d max The indentation depth d for measuring nanohardness n Satisfy the following relationship: d n ≥0.2d max .

[0015] In some embodiments, step S3 includes the following sub-steps:

[0016] S3.1 Surface coating is applied to standard samples, unirradiated metal samples, and irradiated metal samples with different irradiation damage amounts;

[0017] S3.2 Select the first laser frequency and the second laser frequency, use the coated standard sample for calibration test, and use the coated but unirradiated metal sample for applicability test;

[0018] S3.3 Determine the test depth for unirradiated and irradiated coated metal samples;

[0019] S3.4 Calculate the test laser frequency based on the test depth;

[0020] S3.5. Based on the test laser frequency, measure the surface thermal conductivity of the unirradiated metal sample and the irradiated metal sample.

[0021] In some embodiments, in step S3.1, the standard sample is aluminum oxide; and / or, the coating thickness is 70 nm to 90 nm; and / or, the composition of the film is aluminum or gold.

[0022] In some embodiments, in step S3.2, both the first laser frequency and the second laser frequency are 0.1MHz to 10MHz.

[0023] In some embodiments, during step S3.2, the surface thermal conductivity of the coated standard sample is tested in the calibration test to obtain the thermal conductivity k of the coated standard sample at the first laser frequency. b1 Thermal conductivity k of the standard sample coated at the second laser frequency b2 Determine whether the following relation is satisfied: k b1 =k b2 = The theoretical thermal conductivity value of the standard sample; if so, then a suitability test is performed; and / or, in the suitability test, the surface thermal conductivity of the unirradiated metal sample with coating is tested to obtain the thermal conductivity k of the unirradiated metal sample with coating at the first laser frequency. u1 Thermal conductivity k of the unirradiated metal sample coated at the second laser frequency u2 Determine whether the following relation is satisfied: k u1 =k u2 If so, proceed to the next step.

[0024] In some embodiments, in step S3.3, the test depth d k With the maximum irradiation damage depth d max The following relationship is satisfied: 0.2d max ≤d k ≤0.9d max .

[0025] In some embodiments, in step S3.4, the test laser frequency f0 is calculated using equation (1):

[0026]

[0027] Where, k u1 d is the thermal conductivity of the unirradiated metal sample with coating at the first laser frequency, C is the volumetric heat capacity of the unirradiated metal sample with coating, and d is the thermal conductivity of the unirradiated metal sample with coating. k For testing depth.

[0028] In some embodiments, in step S6, the ductile-brittle transition temperature increment ΔT of the irradiated metal sample is calculated using equation (2):

[0029] ΔT=178.1×(H p -H0) (2)

[0030] Among them, H p H represents the nanohardness of the metal sample after irradiation, and H0 represents the nanohardness of the unirradiated metal sample.

[0031] The beneficial effects of the present invention are as follows: The method for evaluating the irradiation embrittlement of metal materials of the present invention can effectively evaluate the irradiation embrittlement level of metal materials by non-destructive measurement of the surface thermal conductivity of metal materials. The irradiation embrittlement evaluation method of the present invention has the following advantages: 1) It does not cause damage to the metal materials; 2) It can evaluate the irradiation embrittlement level remotely or across transparent media; 3) It can evaluate the irradiation embrittlement level in real time. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0033] Figure 1 This is the irradiation damage amount-damage depth curve of Embodiment 1 of the present invention;

[0034] Figure 2 This is the nanohardness-surface thermal conductivity curve of Example 1 of the present invention. Detailed Implementation

[0035] To provide a clearer understanding of the technical features, objectives, and effects of this invention, the invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the invention and do not constitute a limitation on the scope of protection of this invention.

[0036] This invention proposes a method for assessing the irradiation embrittlement of metallic materials based on surface thermal conductivity. The metallic material can be reactor pressure vessel (RPV) steel. The irradiation embrittlement assessment method includes the following steps:

[0037] S1. Irradiate the metal sample to be tested, establish the irradiation damage amount-damage depth curve, and obtain the maximum irradiation damage depth.

[0038] In step S1, the irradiation is proton irradiation, heavy ion irradiation, or neutron irradiation, and the irradiation energy can be 220keV to 260keV, such as 220keV, 230keV, 240keV, 250keV, or 260keV. In other embodiments, irradiation can also be performed using protons, heavy ions, or neutrons with other irradiation energy values. The specific irradiation conditions can be selected according to actual needs. Based on elements with a mass percentage ≥5% in the metal sample to be tested, the irradiation damage amount-damage depth curve of the metal sample to be tested after irradiation is calculated. Among them, the exposition threshold energy of each metal element is as follows: the exposition threshold energy E of Fe (iron), Cr (chromium), Ni (nickel), Mn (manganese), Co (cobalt), and Zr (zirconium). d =40eV, the dislocation threshold energy E of Al (aluminum) and Pb (lead) d =25eV, the exposition threshold energy E of Cu (copper) and Ti (titanium) d =30eV, the exposition threshold energy of Mo (molybdenum) and Nb (niobium) d=60eV, the exposition threshold energy E of W (tungsten) d =90 eV. Further, based on the irradiation damage amount-damage depth curve, the maximum irradiation damage depth d corresponding to the maximum irradiation damage amount in the curve is determined. max If the radiation damage distribution in the curve is uniform, then the maximum radiation damage depth d max Assigned the value d max =1μm.

[0039] S2. Measure the nanohardness of unirradiated metal samples and irradiated metal samples with different irradiation damage levels.

[0040] In step S2, nanohardness is measured using a nanoindenter. During the measurement process, the maximum irradiation damage depth d is... max The indentation depth d of nanoindentation n Satisfy the following relationship: d n ≥0.2d max Different irradiation damage levels include at least three, such as three, four, or five, with irradiation damage levels of 0.1 dPa, 0.3 dPa, 0.7 dPa, 1.0 dPa, 1.6 dPa, etc. The nanohardness H0 of the unirradiated metal sample and the nanohardness H of the irradiated metal sample with at least three irradiation damage levels are measured. i1 H i2 H i3 wait.

[0041] S3. Determine the test laser frequency and measure the surface thermal conductivity of the unirradiated metal sample and irradiated metal samples with different levels of irradiation damage. Specifically, step S3 includes the following sub-steps:

[0042] S3.1 Surface coating is applied to standard samples, unirradiated metal samples, and irradiated metal samples with different irradiation damage levels.

[0043] In step S3.1, the standard sample can be aluminum oxide (Al2O3), which has high stability and consistent surface thermal conductivity. The coating thickness can be 70nm to 90nm, such as 70nm, 75nm, 80nm, 85nm, or 90nm. The film composition can be aluminum (Al) or gold (Au). Surface coating can be performed using methods such as magnetron sputtering or arc ion plating. Understandably, surface coating of metal materials is an existing technology, and its process parameters can be selected according to actual process conditions, without specific limitations here.

[0044] S3.2 Select the first laser frequency and the second laser frequency, conduct calibration tests using coated standard samples, and conduct applicability tests using coated but unirradiated metal samples.

[0045] In step S3.2, the first laser frequency f1 and the second laser frequency f2 are both selected within the range of 0.1MHz to 10MHz, such as 0.1MHz, 1MHz, 3MHz, 7MHz, or 10MHz. The first laser frequency f1 and the second laser frequency f2 are not equal; preferably, f1 = 1.82MHz and f2 = 9.70MHz.

[0046] The calibration test is used to calibrate and verify the adjusted thermal conductivity testing equipment. Specifically, based on the first laser frequency and the second laser frequency, the surface thermal conductivity of the coated standard sample is tested to obtain the thermal conductivity k of the coated standard sample at the first laser frequency. b1 Thermal conductivity k of the standard sample coated at the second laser frequency b2 Determine if the following relation is satisfied: k b1 =k b2 = The theoretical thermal conductivity value of the standard sample. If yes, it indicates that the thermal conductivity testing equipment has passed calibration and can be used for applicability testing; if not, the thermal conductivity testing equipment needs to be readjusted. The theoretical thermal conductivity value of aluminum oxide is 36 W / mK.

[0047] In the applicability test, a calibrated thermal conductivity testing device was used to verify whether the metallic material was suitable for the irradiation embrittlement assessment method of the present invention. Specifically, based on a first laser frequency and a second laser frequency, the surface thermal conductivity of the unirradiated coated metallic sample was tested to obtain the thermal conductivity k of the unirradiated coated metallic sample at the first laser frequency. u1 Thermal conductivity k of the unirradiated metal sample coated at the second laser frequency u2 Determine if the following relation is satisfied: k u1 =k u2 If yes, it indicates that the thickness direction of the metal sample is independent of the laser frequency, and the next step can be carried out; if no, it indicates that the metal material is not suitable for the irradiation embrittlement assessment method of the present invention, and the test should be stopped.

[0048] S3.3 Determine the test depth for unirradiated and irradiated coated metal samples.

[0049] In step S3.3, the test depth d k With the maximum irradiation damage depth d max The following relationship is satisfied: 0.2d max ≤d k ≤0.9d max .

[0050] S3.4 Calculate the test laser frequency based on the test depth.

[0051] In step S3.4, the test laser frequency f0 is calculated using equation (1):

[0052]

[0053] Where, k u1 Let d be the thermal conductivity of the unirradiated metal sample at the first laser frequency in step S3.2, C be the volumetric heat capacity of the unirradiated metal sample, and d be the thermal conductivity of the unirradiated metal sample at the first laser frequency. k This refers to the test depth in step S3.3.

[0054] S3.5. Based on the test laser frequency f0 in step S3.4, measure the surface thermal conductivity of unirradiated metal samples and irradiated metal samples with different irradiation damage amounts.

[0055] S4. Based on the nanohardness measured in step S2 and the surface thermal conductivity measured in step S3, the least squares method is used to fit and establish the nanohardness-surface thermal conductivity curve.

[0056] S5. Based on the test laser frequency f0 in step S3.4, measure the surface thermal conductivity K of the metal sample after irradiation. p Based on the nanohardness-surface thermal conductivity curve obtained in step S4, the nanohardness H of the irradiated metal sample was determined. p .

[0057] S6. Nanohardness H of the irradiated metal sample based on step S5. p The nanohardness H0 of the unirradiated metal sample in step S2 is used to calculate the ductile-brittle transition temperature increment of the metal sample after irradiation in order to assess the level of irradiation embrittlement of the metal material.

[0058] In step S6, the ductile-brittle transition temperature increment ΔT of the metal sample after irradiation is calculated using equation (2):

[0059] ΔT=178.1×(H p -H0) (2)

[0060] Among them, H p H represents the nanohardness of the metal sample after irradiation, and H0 represents the nanohardness of the unirradiated metal sample.

[0061] This invention provides a novel method for assessing the irradiation embrittlement of metallic materials. By non-destructively measuring the surface thermal conductivity of metallic materials, the irradiation embrittlement level can be effectively evaluated. The irradiation embrittlement assessment method of this invention has the following advantages: 1) The assessment method does not damage the metallic material, making it a non-destructive assessment technique; 2) The irradiation embrittlement level of metallic materials can be assessed remotely or across transparent media; 3) The irradiation embrittlement level of metallic materials can be assessed in real time.

[0062] The following is an illustration through specific examples:

[0063] Example 1

[0064] The irradiation embrittlement assessment method for metallic materials based on surface thermal conductivity of the present invention is used to assess the irradiation embrittlement of RPV steel. The assessment method includes the following steps:

[0065] S1. Irradiate the metal sample to be tested, establish an irradiation damage amount-damage depth curve, and obtain the maximum irradiation damage depth. The metal sample to be tested is RPV steel.

[0066] In step S1, the irradiation is 240 keV proton irradiation. Since the Fe content in the RPV steel is ≥95%, only Fe is considered in the calculations, and the Fe exposition threshold energy E... d =40eV. The irradiation damage dose-damage depth curve is shown below. Figure 1 As shown, the maximum irradiation damage depth d corresponds to the maximum irradiation damage amount. max =1000nm.

[0067] S2. Measure the nanohardness of unirradiated metal samples and irradiated metal samples with different irradiation damage levels.

[0068] In step S2, a nanoindenter is used to measure nanohardness. During the measurement process, the indentation depth d of the nanoindentation is measured. n =0.2d max =200nm. Different irradiation damage levels include 0.3dPa, 1.0dPa, and 1.6dPa. The nanohardness H0 of the unirradiated metal sample and the nanohardness H of the irradiated metal samples with different irradiation damage levels were measured. i1 H i2 H i3 The measurement results are shown in Table 1.

[0069] Table 1. Results of Nanohardness Measurement

[0070] Nanohardness / GPa 2.74 4.12 4.57 4.78 Error / GPa 0.15 0.26 0.21 0.31 Irradiation damage dose / dpa 0 0.3 1.0 1.6

[0071] S3. Determine the test laser frequency and measure the surface thermal conductivity of the unirradiated metal sample and irradiated metal samples with different levels of irradiation damage. Specifically, step S3 includes the following sub-steps:

[0072] S3.1 Surface coating is applied to standard samples, unirradiated metal samples, and irradiated metal samples with different irradiation damage levels. Among them, the metal samples are RPV steel samples.

[0073] In step S3.1, the standard sample is Al2O3, the coating thickness is 80 nm, and the film composition is Al. The surface coating is applied using magnetron sputtering; specific process parameters can be selected according to actual needs and are not limited.

[0074] S3.2 Select the first laser frequency and the second laser frequency, conduct calibration tests using coated standard samples, and conduct applicability tests using coated but unirradiated metal samples.

[0075] In step S3.2, the first laser frequency f1 = 1.82MHz and the second laser frequency f2 = 9.70MHz.

[0076] In the calibration experiment, the surface thermal conductivity of the coated standard sample was tested based on the first laser frequency f1 and the second laser frequency f2, and the thermal conductivity k of the coated standard sample at the first laser frequency was obtained. b1 Thermal conductivity k of the standard sample coated at the second laser frequency b2 k b1 =k b2 =The theoretical thermal conductivity of Al2O3 is 36W / mK, indicating that the thermal conductivity testing equipment has been calibrated successfully.

[0077] In the applicability test, the surface thermal conductivity of the un-irradiated metal sample with coating was tested based on the first laser frequency f1 and the second laser frequency f2, and the thermal conductivity k of the un-irradiated metal sample with coating at the first laser frequency was obtained. u1 Thermal conductivity k of the unirradiated metal sample coated at the second laser frequency u2 k u1 =k u2 =39.8W / mK, indicating that the thickness direction of the metal sample is independent of the laser frequency.

[0078] S3.3 Determine the test depth for unirradiated and irradiated coated metal samples.

[0079] In step S3.3, the test depth d k =0.88d max =880nm.

[0080] S3.4 Calculate the test laser frequency based on the test depth.

[0081] In step S3.4, the test laser frequency f0 is calculated using equation (1):

[0082]

[0083] Where, k u1 Let d be the thermal conductivity of the unirradiated metal sample at the first laser frequency in step S3.2, C be the volumetric heat capacity of the unirradiated metal sample, and d be the thermal conductivity of the unirradiated metal sample at the first laser frequency. k This refers to the test depth in step S3.3.

[0084] According to k u1 =39.8W / mK, C=4×10 6 J / (m 3K), d k =880nm, the calculated test laser frequency f0 = 4.12MHz.

[0085] S3.5. Based on the test laser frequency f0 obtained in step S3.4, measure the surface thermal conductivity of the unirradiated metal sample and irradiated metal samples with different irradiation damage amounts to obtain the surface thermal conductivity k0 of the unirradiated metal sample and the surface thermal conductivity k of the irradiated metal samples with different irradiation damage amounts (0.3 dPa, 1.0 dPa, 1.6 dPa). i1 k i2 k i3 The measurement results are shown in Table 2.

[0086] Table 2 Surface thermal conductivity measurement results

[0087] Surface thermal conductivity, W / mK 39.8 35.0 34.7 31.9 Error, W / mK 0.4 0.8 1.4 1.8 Radiation damage, dpa 0 0.3 1.0 1.6

[0088] S4. Based on the nanohardness measured in step S2 and the surface thermal conductivity measured in step S3, the least squares method is used for fitting to establish the nanohardness-surface thermal conductivity curve (Hk curve). Figure 2 As shown, the curve formula is H = -0.29327k + 14.46, R 2 =0.9359.

[0089] S5. Based on the test laser frequency f0 in step S3.4, measure the surface thermal conductivity K of the metal sample after irradiation. p Based on the nanohardness-surface thermal conductivity curve obtained in step S4, the nanohardness H of the irradiated metal sample was determined. p Among them, K p =36W / mK, H p =3.90 GPa.

[0090] S6. Nanohardness H of the irradiated metal sample based on step S5. p The nanohardness H0 of the unirradiated metal sample in step S2 is used to calculate the ductile-brittle transition temperature increment of the metal sample after irradiation in order to assess the level of irradiation embrittlement of the metal material.

[0091] In step S6, the ductile-brittle transition temperature increment ΔT of the metal sample after irradiation is calculated using equation (2):

[0092] ΔT=178.1×(H p -H0) (2)

[0093] Among them, H p H represents the nanohardness of the metal sample after irradiation, and H0 represents the nanohardness of the unirradiated metal sample.

[0094] According to H p=3.90GPa, H0=2.74GPa, the ductile-brittle transition temperature increment ΔT of the metal sample after irradiation is calculated to be 206.6℃.

[0095] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity, characterized in that, Includes the following steps: S1. Irradiate the metal sample to be tested, establish the irradiation damage amount-damage depth curve, and obtain the maximum irradiation damage depth. S2. Measure the nanohardness of unirradiated metal samples and irradiated metal samples with different irradiation damage amounts. S3. Determine the test laser frequency and measure the surface thermal conductivity of the unirradiated metal sample and the irradiated metal samples with different irradiation damage amounts. S4. Based on the measurement results of steps S2 and S3, establish the nano-hardness-surface thermal conductivity curve; S5. Based on the test laser frequency, measure the surface thermal conductivity of the metal sample to be tested after irradiation, and determine the nanohardness of the metal sample to be tested after irradiation according to the nanohardness-surface thermal conductivity curve. S6. Based on the nanohardness of the metal sample to be tested after irradiation and the nanohardness of the unirradiated metal sample, calculate the ductile-brittle transition temperature increment of the metal sample to be tested after irradiation to evaluate the irradiation embrittlement level of the metal material.

2. The method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity according to claim 1, characterized in that, In step S1, the irradiation is proton irradiation, heavy ion irradiation, or neutron irradiation, with an irradiation energy of 220 keV to 260 keV; and / or, Based on the elements with a mass percentage ≥ 5% in the metal sample to be tested, the irradiation damage amount-damage depth curve of the metal sample to be tested after irradiation is calculated.

3. The method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity according to claim 1, characterized in that, In step S2, the maximum irradiation damage depth d max The indentation depth d for measuring nanohardness n Satisfy the following relationship: d n ≥0.2d max .

4. The method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity according to claim 1, characterized in that, Step S3 includes the following sub-steps: S3.

1. Apply a surface coating to the standard sample, the unirradiated metal sample, and the irradiated metal samples with different irradiation damage amounts; S3.2 Select the first laser frequency and the second laser frequency, use the coated standard sample for calibration test, and use the coated but unirradiated metal sample for applicability test; S3.3 Determine the test depth of the unirradiated metal sample and the irradiated metal sample with coating; S3.

4. Calculate the test laser frequency based on the test depth; S3.

5. Based on the test laser frequency, measure the surface thermal conductivity of the unirradiated metal sample and the irradiated metal sample.

5. The method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity according to claim 4, characterized in that, In step S3.1, the standard sample is aluminum oxide; and / or, the coating thickness is 70nm~90nm; and / or, the composition of the film is aluminum or gold.

6. The method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity according to claim 4, characterized in that, In step S3.2, both the first laser frequency and the second laser frequency are 0.1MHz to 10MHz.

7. The method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity according to claim 4 or 6, characterized in that, In step S3.2, during the calibration test, the surface thermal conductivity of the coated standard sample is tested to obtain the thermal conductivity k of the coated standard sample at the first laser frequency. b1 The thermal conductivity k of the coated standard sample at the second laser frequency b2 Determine whether the following relation is satisfied: k b1 =k b2 =The theoretical thermal conductivity value of the standard sample; if so, then the aforementioned suitability test shall be conducted. In the applicability test, the surface thermal conductivity of the unirradiated metal sample with the coating was tested to obtain the thermal conductivity k of the unirradiated metal sample with the coating at the first laser frequency. u1 The thermal conductivity k of the unirradiated metal sample coated at the second laser frequency. u2 Determine whether the following relation is satisfied: k u1 =k u2 If so, proceed to the next step.

8. The method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity according to claim 4, characterized in that, In step S3.3, the test depth d k With the maximum irradiation damage depth d max It satisfies the following relationship: 0.2 d max ≤d k ≤0.9 d max .

9. The method for evaluating the irradiation embrittlement of metallic materials based on surface thermal conductivity according to claim 1, characterized in that, In step S6, the ductile-brittle transition temperature increment ΔT of the metal sample after irradiation is calculated using equation (2): ΔT=178.1×(H p -H0) (2) Among them, H p H0 represents the nanohardness of the metal sample to be tested after irradiation, while H0 represents the nanohardness of the unirradiated metal sample.

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