A method and system for determining temperature / strain rate dependence of metal strength

Abstract

This invention discloses a method and system for determining the temperature / strain rate dependence of metal strength, belonging to the field of micro-nano technology. The method obtains the compression or tension stress-strain curves of micro-nano metal samples, as well as the background noise of the no-load test. Based on the background noise, the maximum displacement rate of the micro-nano mechanical testing instrument is determined and used as a threshold. Based on the threshold, the stress-strain curves are iterated to determine the start and end points of all dislocation avalanches, the total plastic displacement of the dislocation avalanches, and the intensity ratio of the micro-nano metal sample, thereby determining the temperature / strain rate dependence of the metal strength. This method, through testing a single sample at room temperature and calculating the intensity ratio, can quantitatively and accurately confirm whether the strength is temperature-dependent, thus avoiding the limitations of qualitative analysis and the need for multiple multi-sample experiments to save time, manpower, and other experimental costs.

Description

Technical Field

[0001] This invention relates to the field of micro-nano technology, specifically to a method and system for determining the temperature / strain rate dependence of metal strength. Background Technology

[0002] Metals with body-centered cubic lattice structures, such as molybdenum, niobium, and tungsten, possess exceptional material properties, including high-temperature mechanical strength, high thermal stability, excellent creep resistance, high melting point, low ductile-brittle transition temperature, and low resistivity. For example, metal body-centered cubic nanobeam lattices, with their extremely small size and excellent mechanical properties, are used in numerous fields; niobium nanowires, with their high strength and excellent deformability, are considered important materials for constructing nanoscale electromechanical devices; and single-crystal molybdenum, due to its high thermal stability, high melting point, low resistivity, and thermal expansion coefficient matching that of silicon lattices, has been selected as a gate material for complementary metal-oxide-semiconductor systems. Because of the electrothermal effect, these applications require operation at various temperatures, making it crucial to determine whether the material's strength changes drastically with temperature. However, the strength of micro / nano metallic materials exhibits a size effect, necessitating the fabrication of materials of appropriate sizes for micro / nano mechanical property testing, rather than evaluation through bulk material performance testing.

[0003] Current methods for determining whether the strength of micro / nano-scale metallic materials exhibits temperature / strain rate dependence involve comparing stress-strain curves obtained from tensile / compressive stresses on micro / nano-sized samples. This requires conducting experiments with multiple samples at various target temperatures and strain rates, necessitating complex temperature and strain rate variations and increasing time and labor costs. Furthermore, unlike experimental testing of macroscopic bulk materials, quantitative mechanical experiments on micro / nano-scale materials face challenges such as the determination and analysis of minute mechanical quantities: variable-temperature micro / nano mechanical testing equipment is scarce, has a narrow temperature range, and is expensive; the testing atmosphere and suitable indenter materials need to be controlled to prevent chemical changes or reactions with the indenter at high temperatures; and the temperature difference between the sample and the indenter requires significant time to achieve proper matching to avoid thermal drift. Therefore, carefully designed experiments and equipment are needed to ensure accurate and reliable data from high-temperature tests, making the testing highly challenging. Thus, a simple method for determining the degree of change in yield strength or flow stress with temperature and strain rate is urgently needed. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a method and system for determining the temperature / strain rate dependence of metal strength. The method determines whether the plastic deformation of the material is dominated by screw dislocations by calculating the proportion of plastic deformation caused by dislocation avalanche to the total plastic deformation, thereby obtaining whether its strength is dependent on temperature and strain rate.

[0005] This invention is achieved through the following technical solution:

[0006] The first invention provides a method for determining the temperature / strain rate dependence of metal strength, comprising the following steps:

[0007] Under constant strain rate conditions, the stress-strain curves of micro- and nano-sized metal samples and the background noise of the no-load test were obtained.

[0008] The maximum displacement rate of the micro-nano mechanical system of the experimental instrument is determined based on the background noise and used as the threshold under strain-free jump signal.

[0009] By using a threshold to traverse the stress-strain curves, the starting and ending points of each dislocation avalanche in the micro / nano metal sample are determined.

[0010] The total plastic displacement of dislocation avalanches is determined by identifying the initiation and termination points of the avalanches. Combined with the total plastic deformation of the nano-metal sample experiments, the intensity ratio of the micro / nano metal samples is determined. The temperature / strain rate dependence of the metal strength is then determined based on the intensity ratio.

[0011] Preferably, the method for determining the stress-strain curve includes:

[0012] Experimental instruments were used to test micro- and nano-sized metal samples to obtain force-displacement curves, and stress-strain curves were calculated based on the force-displacement curves.

[0013] Preferably, the background noise of the no-load test includes:

[0014] Using the same experimental conditions, an unloaded experiment was conducted with the experimental instrument to obtain the time and displacement data of the instrument head, which were then used as the background noise of the instrument.

[0015] Preferably, the determination of the maximum displacement rate of the experimental instrument includes:

[0016] The displacement rate at each moment is determined based on time and displacement data, and then the maximum displacement rate is determined.

[0017] The expression for displacement rate is as follows:

[0018] (D n -D n-1 ) / (t n -t n-1 )

[0019] Where D is displacement and t is time.

[0020] Preferably, the determination of the total plastic displacement includes:

[0021] Calculate the corresponding plastic displacement based on the starting and ending points of each dislocation avalanche, and sum the plastic displacements of all dislocation avalanches to obtain the total plastic displacement corresponding to the total dislocation avalanche.

[0022] Preferably, the method for calculating the plastic displacement of the dislocation avalanche is as follows:

[0023]

[0024] in, , , and For the displacement and force at the beginning and end of the displacement jump, respectively. The theoretical stiffness of the specimen is given.

[0025] Preferably, the method for determining the intensity ratio is as follows:

[0026]

[0027] in, For all extracted dislocation avalanches, The displacement represents the total plastic deformation, with the percentage of severe deformation ranging from 0% to 100%.

[0028] Preferably, the temperature / strain rate dependence of determining the metal strength based on the intensity ratio includes:

[0029] Comparing the intensity percentage with 50%, if the intensity percentage is less than 50%, the metallic material exhibits temperature / strain rate dependence.

[0030] The second invention provides a system for determining the temperature / strain rate dependence of metal strength, comprising:

[0031] The acquisition module is used to acquire the stress-strain curves of micro- and nano-sized metal samples under constant strain rate conditions, as well as the background noise of the no-load experiment.

[0032] The rate module is used to determine the maximum displacement rate of the experimental instrument used in the experiment based on the background noise, and to serve as the threshold under strain-free jump signal.

[0033] The dislocation avalanche traversal module is used to traverse the stress-strain curve using a threshold to determine the start and end points of all dislocation avalanches in the nanoscale metal sample.

[0034] The analysis module is used to determine the total plastic displacement of dislocation avalanches based on the start and end points of the dislocation avalanches, and to determine the intensity ratio of the nanometal sample by combining the total plastic deformation of the nanometal sample experiment. Based on the intensity ratio, the temperature / strain rate dependence of the metal strength is determined.

[0035] The third invention, this application provides an electronic device, including:

[0036] Memory, used to store computer programs;

[0037] A processor, used to execute the computer program to implement the steps of a method for determining the temperature / strain rate dependence of metal strength as described.

[0038] Compared with the prior art, the present invention has the following beneficial technical effects:

[0039] This application presents a method for determining the temperature / strain rate dependence of metal strength. By directly observing dislocation avalanche characteristics on the stress-strain curve and combining this with a severity ratio criterion, the method efficiently determines the temperature / strain rate dependence of metal strength using a single-sample approach. By introducing the severity ratio criterion—the proportion of plastic deformation caused by dislocation avalanche to the total plastic deformation—the contribution of dislocation avalanche to the plastic deformation of the material can be quantitatively assessed. This not only provides specific numerical evidence for judging the strength dependence of materials but also opens up possibilities for further research on the dislocation avalanche mechanism and its relationship with material properties. Secondly, this method is based on the physical mechanism of dislocation motion in body-centered cubic metals, particularly the dominant role of screw dislocations in plastic deformation and the relationship between dislocation avalanche and screw dislocation motion rates. This physical mechanism-based judgment method is more scientific and convincing, enabling a deeper understanding of material deformation behavior. Furthermore, this method determines the temperature / strain rate dependence of metal strength by directly observing dislocation avalanche characteristics on the stress-strain curve, avoiding the complex physical models and indirect measurement methods involved in traditional methods. The strain jumps generated by dislocation avalanches in micron / submicron scale materials are intuitive and measurable, thereby improving the accuracy and reliability of the judgment.

[0040] This application also proposes a system for determining the temperature / strain rate dependence of metal strength, an electronic device, and a computer storage medium, which possess all the advantages of the aforementioned methods for determining the temperature / strain rate dependence of metal strength. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a force-displacement curve diagram illustrating an example of the present invention;

[0043] Figure 2 This is a threshold determination diagram under strain-free abrupt signal in Embodiment 1 of the present invention;

[0044] Figure 3 This is the strain jump map extracted based on a threshold in Embodiment 1 of the present invention;

[0045] Figure 4 This is an example diagram of a strain jump in Embodiment 1 of the present invention;

[0046] Figure 5 This is a time-displacement rate diagram of the micropillar in Embodiment 2 of the present invention;

[0047] Figure 5 a is a threshold determination diagram under strain-free jump signal in Example 2;

[0048] Figure 5 b is the strain jump map extracted based on the threshold in Example 2;

[0049] Figure 6 The diagram shows the room temperature compressive stress-strain curve and yield strength variation with temperature of the micropillar of the present invention.

[0050] Figure 6 a represents the room temperature compressive stress-strain curves of the 1000nm and 3500nm micropillars of this invention;

[0051] Figure 6 b is a graph showing the change in yield strength of the 1000nm and 3500nm micropillars of the present invention with temperature;

[0052] Figure 7 The compressive stress-strain curves of the 1000nm and 3500nm micropillars of this invention at different temperatures are shown.

[0053] Figure 7 a represents the compressive stress-strain curves of the 1000nm micropillar of this invention at different temperatures;

[0054] Figure 7 b represents the compressive stress-strain curves of the 3500nm micropillar of this invention at different temperatures;

[0055] Figure 8 The room temperature compressive stress-strain curve and the yield strength as a function of strain rate of the micropillar of the present invention are shown.

[0056] Figure 8 a represents the room temperature compressive stress-strain curves of the 1000nm and 1500nm micropillars of this invention;

[0057] Figure 8 b is a graph showing the variation of yield strength of the 1000nm and 1500nm micropillars of the present invention with strain rate.

[0058] Figure 9 The compressive stress-strain curves of the 1000nm and 1500nm micropillars of this invention at different strain rates are shown.

[0059] Figure 9 a represents the compressive stress-strain curves of the 1000nm micropillar of this invention at different strain rates;

[0060] Figure 9 b represents the compressive stress-strain curves of the 1500nm micropillar of this invention at different strain rates. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0062] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0063] The strong temperature / strain rate dependence of the strength of body-centered cubic (BCC) metals stems from the fact that the dislocations within BCCs have a non-planar core structure, resulting in a complex dislocation core structure and significant Pearse stress. At low temperatures, the movement of screw dislocations primarily occurs through the formation of kinks, a process mainly controlled by thermally activated screw dislocations, thus endowing BCCs with strong temperature and strain rate dependence. As temperature and strain rate increase, thermal activation reduces the sliding stress of screw dislocations, leading to a sharp decrease in the flow stress of the BCC until the athermal transition temperature is reached. Therefore, the essence of whether BCCs exhibit temperature and strain rate dependence lies in whether plastic deformation is dominated by screw dislocations.

[0064] During plastic deformation of metallic crystals, long-range interactions occur between dislocations, resulting in hundreds or thousands of dislocations moving simultaneously at high speeds in an instant—a phenomenon known as dislocation avalanche. For macroscopic materials, the displacements generated by dislocation avalanches are very small compared to the material size and cannot be directly detected. However, for micrometer / submicrometer scale materials, the displacements generated by dislocation avalanches are on the order of magnitude of the material size, producing dramatic strain jumps on the stress-strain curve, which can be directly measured. This application will utilize this fundamental characteristic to determine whether metallic materials exhibit temperature / strain rate sensitivity.

[0065] The detection principle of this application is as follows: if the strength of a body-centered cubic (BCC) metal exhibits a strong temperature / strain rate dependence, its plastic deformation should be primarily controlled by screw dislocations. The screw dislocation movement rate depends on the thermal activation intensity; at the same temperature, the average screw dislocation movement rate is constant, preventing rapid movement and thus preventing dislocation avalanche. Conversely, if obvious dislocation avalanche characteristics are observed on the stress-strain curve, it indicates that the plastic deformation of the BCC metal is not dominated by screw dislocations, and therefore its strength should not depend on temperature and strain rate. Based on this principle, a single-sample method is used to test whether the deformation of a single sample at room temperature is dominated by screw dislocations, thereby determining whether the material's strength is dependent on temperature and strain rate.

[0066] The method for determining the temperature / strain rate dependence of metal strength in this application is based on the fact that dislocation avalanche exhibits a strong strain jump on the stress-strain curve. It introduces the intensity ratio, that is, the proportion of plastic deformation caused by dislocation avalanche to the total plastic deformation. By calculating the intensity ratio, it is determined whether the plastic deformation of the material is dominated by screw dislocations, thereby obtaining whether its strength is dependent on temperature and strain rate.

[0067] A method for determining the temperature / strain rate dependence of metal strength includes the following steps:

[0068] Step 1: Under constant strain rate conditions, obtain the stress-strain curves of micro / nano metal samples.

[0069] Micro- and nano-metals are prepared using techniques such as focused ion beam or chemical etching to create metal samples for mechanical testing.

[0070] At room temperature, compression / tension experiments were conducted on micro / nano metals to obtain force-displacement curves of the metal samples.

[0071] Analyzing the force-displacement curve reveals a sawtooth deformation curve caused by dislocation avalanches. (See attached image.) Figure 1 .

[0072] Step 2: Under the same experimental conditions as in Step 1, obtain the background noise of the no-load test, determine the maximum value of the displacement rate based on the background noise, and use it as the threshold under the strain-free jump signal.

[0073] Using the same experimental parameters as in step 1, an unloaded experiment was conducted using a micro-nano mechanical instrument to obtain the time and displacement data of the instrument head. This time and displacement data is the background noise.

[0074] Time and displacement data are denoted as [t1, t2...t], respectively. n [D1,D2...D] and [D2,D2...D2] n Based on time and displacement data, the displacement rate at each moment is determined, and the maximum displacement rate is used as the threshold under the strain-free jump signal. Figure 2 As shown.

[0075] The displacement rate is calculated as follows:

[0076] (D n -D n-1 ) / (t n -t n-1 )

[0077] Step 3: Use a threshold to traverse the stress-strain curves to determine the start and end points of all dislocation avalanches.

[0078] Dislocation avalanches can be extracted from the displacement velocity-time signal based on the maximum value of the background noise displacement velocity. (See also...) Figure 3 Signals exceeding the threshold all originate from dislocation avalanches. Specifically, data is retrieved starting at t=0; when the displacement velocity exceeds the threshold, a dislocation avalanche is determined to have occurred, and the displacement and force at this point are denoted as D. s and F s Then, when the displacement rate is less than the threshold, the dislocation avalanche ends, and the displacement and force at this time are denoted as D. e and F e .

[0079] By traversing the entire force-displacement curve, the displacements and forces at the beginning and end of all dislocation avalanches can be recorded. (Appendix) Figure 4 The starting and ending points of a specific strain jump extracted are given on the force-displacement curve.

[0080] Step 4: Determine the plastic displacement of each dislocation avalanche based on its starting and ending points, and sum them to obtain the total plastic displacement of all dislocation avalanches.

[0081] The magnitude of the plastic displacement caused by the dislocation avalanche can be calculated by identifying the initiation and termination points of the avalanche, as shown in the following expression:

[0082]

[0083] in, , , and For the displacement and force at the beginning and end of the displacement jump, respectively. The theoretical stiffness of the specimen is given.

[0084] Step 5: Determine the intensity ratio of the micro / nano metal sample based on the total plastic displacement of the dislocation avalanche and the total plastic deformation of the micro / nano metal sample.

[0085] The intensity ratio is defined as the proportion of plastic deformation caused by dislocation avalanches to the total plastic deformation.

[0086] Total plastic deformation refers to the total displacement deformation of the micro / nano metal sample from the start of yielding to the end of the experiment.

[0087] The expression for the percentage of severe cases is as follows:

[0088]

[0089] in, The plastic displacements of all extracted dislocation avalanches are represented. The displacement represents the total plastic deformation, with the percentage of severe deformation ranging from 0% to 100%.

[0090] Step 6: Compare the intensity percentage with 50% to determine whether the metal exhibits temperature and strain rate dependence.

[0091] By using the strength percentage measured at room temperature, and taking 50% as the threshold, we can determine whether the strength is temperature and strain rate dependent.

[0092] If the proportion of high-strength material is >50%, it indicates that screw dislocations do not dominate plastic deformation at this time, and it can be determined that the material strength is not strongly dependent on temperature / strain rate.

[0093] If the ratio of stress is less than 50%, it indicates that screw dislocations dominate plastic deformation, and therefore the material strength is highly dependent on temperature / strain rate.

[0094] This method replaces complex temperature and strain rate variations in experiments. Given that micrometer / submicrometer scale materials need to operate at different temperatures, verifying whether material strength is temperature-dependent requires testing under multiple different temperature conditions. A parameter reflecting dislocation motion—the strength ratio—is proposed. By calculating this value through single-sample testing at room temperature, the temperature dependence of strength can be accurately confirmed through quantitative analysis, thus avoiding the limitations of qualitative analysis and the need for multiple multi-sample experiments, saving time, manpower, and other experimental costs. The same method is also applicable to determining strain rate dependence.

[0095] Example 1

[0096] Taking single-crystal molybdenum micropillars with diameters of 1000 nm and 3500 nm as examples, the method for determining the temperature / strain rate dependence of metal strength described above is used to determine whether the 1000 nm and 3500 nm single-crystal molybdenum micropillars exhibit temperature dependence, as detailed below:

[0097] Step 1: Compress single-crystal Mo micropillars with diameters of 1000 nm and 3500 nm respectively at room temperature, with a strain rate of 2 × 10⁻⁶. - 3 s -1 The stress-strain curves obtained are shown in the attached figure. Figure 6 a.

[0098] Step 2, Calculate the intensity ratio: For a 1000nm micropillar, use the formula (D n -D n-1 ) / (t n -t n-1 The displacement rate of the test sample is calculated, and then dislocation avalanches are extracted from the displacement rate-time signal based on a threshold. (See also...) Figure 2 and Figure 3 Signals exceeding a threshold all originate from dislocation avalanches. After determining the threshold, all strain jumps are extracted using the formula... Summation yields ∑X = 550nm, and D is calculated from the original data. p =625nm, therefore the intensity of a 1000nm micropillar at room temperature is... =88%. For 3500nm micropillars, the same calculation steps yield a virulence ratio W of 1.2% at room temperature.

[0099] Step 3: At room temperature, the percentage of severe deformation in a 1000 nm diameter micropillar is W = 88% > 50%, indicating that the micropillar at this diameter has undergone severe deformation, and its yield strength has no temperature dependence. The percentage of severe deformation in a 3500 nm diameter micropillar is W = 1.2% < 50%, indicating that the micropillar at this diameter has undergone warm deformation, i.e., screw dislocations dominate plastic deformation, and its strength will be temperature dependent. The temperature dependence is as follows: Figure 6 b.

[0100] Step 4: Verify the above results for the 1000nm molybdenum micropillars.

[0101] Four molybdenum micropillars with a diameter of 1000 nm were fabricated and heated to 25℃, 70℃, 140℃, and 200℃ in a vacuum environment. Compression tests were conducted to obtain the strength at different temperatures. Figure 7 In sample a, it can be seen that the material strength does not change with temperature, which is consistent with the judgment result of the single sample method.

[0102] Step 5: Verify the above results for the 3500nm molybdenum micropillars.

[0103] Four molybdenum micropillars with a diameter of 3500 nm were fabricated and heated to 25℃, 70℃, 140℃, and 200℃ in a vacuum environment. Compression tests were conducted to obtain the strength at different temperatures. Figure 7 In sample b, it can be seen that the material strength decreases rapidly with increasing temperature, exhibiting a strong temperature dependence, which is consistent with the judgment result of the single sample method.

[0104] Example 2

[0105] Taking single-crystal molybdenum micropillars with diameters of 1000 nm and 1500 nm as examples, the method for determining the temperature / strain rate dependence of metal strength described above is used to determine whether the 1000 nm and 1500 nm single-crystal molybdenum micropillars exhibit strain rate dependence, as detailed below:

[0106] Step 1: Compress single-crystal molybdenum micropillars with diameters of 1000 nm and 1500 nm respectively at room temperature, with a strain rate of 2 × 10⁻⁶. - 3 s -1 The stress-strain curves obtained are shown in the attached figure. Figure 8 a.

[0107] Step 2, Calculate the intensity ratio: For a 1000nm micropillar, calculate the cumulative probability distribution of displacement rate, determine the threshold, and extract all strain jumps, as shown in the attached figure. Figure 5 This microcolumn is the same as the one in Example 1, with a similar intensity ratio. =88%. For 1500nm micropillars, the same calculation steps yield a virulence ratio of W=31% at room temperature.

[0108] Step 3: At room temperature, the stress percentage (W) of the 1000 nm diameter micropillar is 88% > 50%. According to this invention, the micropillar of this diameter has undergone severe deformation, and its yield strength does not depend on the strain rate. The stress percentage (W) of the 1500 nm diameter micropillar is 31% < 50%. It can be determined that the micropillar of this diameter has undergone warm deformation, that is, screw dislocations dominate plastic deformation, and its strength will depend on the strain rate, as shown in the attached figure. Figure 8 b.

[0109] Step 4: Verify the above results for the 1000nm molybdenum micropillars.

[0110] Three molybdenum micropillars with a diameter of 1000 nm were fabricated and subjected to compressive mechanical property tests at room temperature in an air environment. Different strain rates were selected for compression to obtain the strength at different strain rates. Figure 9 In sample a, it can be seen that the material strength does not change with the strain rate, which is consistent with the judgment result of the single sample method.

[0111] Step 5: Verify the above results for the 1500nm molybdenum micropillars.

[0112] Three molybdenum micropillars with a diameter of 1500 nm were fabricated and their compressive mechanical properties were tested at room temperature in air. Different strain rates were selected for compression to obtain the strength at different strain rates. Figure 9 In sample b, it can be seen that the material strength decreases drastically with decreasing strain rate, exhibiting a strong strain rate dependence, which is consistent with the judgment results of the single-sample method.

[0113] Based on the above method for determining the temperature / strain rate dependence of metal strength, this application also provides a system for determining the temperature / strain rate dependence of metal strength, comprising:

[0114] The acquisition module is used to acquire the stress-strain curves of micro- and nano-sized metal sample compression experiments and the background noise of compression no-load experiments under constant strain rate conditions.

[0115] The rate module is used to determine the maximum displacement rate of the compression test instrument used in the compression test based on the background noise, and to serve as the threshold under the strain-free jump signal.

[0116] The dislocation avalanche traversal module is used to traverse the stress-strain curve using a threshold to determine the start and end points of all dislocation avalanches in micro / nano metal samples.

[0117] The analysis module is used to determine the total plastic displacement of dislocation avalanches based on the start and end points of the dislocation avalanches, and to determine the intensity ratio of the nanometal sample by combining the total plastic deformation of the nanometal sample compression test. Based on the intensity ratio, the temperature / strain rate dependence of the metal strength is determined.

[0118] It should be noted that, in the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules may be combined or integrated into another device, or some features may be ignored or not executed. The modules described as separate components may or may not be physically separated. The components shown as modules may be one or more physical units, that is, they may be located in one place or distributed in multiple different places. Some or all of the modules can be selected to achieve the purpose of the solution in this embodiment according to actual needs.

[0119] Furthermore, in the various embodiments of the present invention, the modules can be integrated into one processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit. The integrated unit described above can be implemented in hardware or as a software functional unit.

[0120] An electronic device provided in this application includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the method for determining the temperature / strain rate dependence of metal strength as described in any of the above embodiments.

[0121] This application provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the steps of the method for determining the temperature / strain rate dependence of metal strength as described in any of the above embodiments.

[0122] For descriptions of relevant parts in the system, electronic device, and computer-readable storage medium for determining the temperature / strain rate dependence of metal strength provided in this application, please refer to the detailed descriptions of the corresponding parts in the method for determining the temperature / strain rate dependence of metal strength provided in this application, which will not be repeated here. Furthermore, parts of the technical solutions provided in this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0123] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for determining the temperature / strain rate dependence of metal strength, characterized in that, Includes the following processes: Under constant strain rate conditions, the stress-strain curves of micro- and nano-sized metal samples and the background noise of the no-load test were obtained. The maximum displacement rate of the micro-nano mechanical system of the experimental instrument is determined based on the background noise and used as the threshold under strain-free jump signal. By using a threshold to traverse the stress-strain curves, the starting and ending points of each dislocation avalanche in the micro / nano metal sample are determined. The total plastic displacement of dislocation avalanches is determined based on the initiation and termination points of the dislocation avalanches. Combined with the total plastic deformation of the nano-metal sample experiments, the intensity ratio of the micro- and nano-metal samples is determined. The temperature / strain rate dependence of the metal strength is determined based on the intensity ratio. The method for calculating the plastic displacement of the dislocation avalanche is as follows: in, and These are the initial and final displacements of the displacement jump, respectively. and These are the forces at the beginning and end of the displacement jump, respectively. The theoretical stiffness of the specimen; The method for determining the intensity ratio is as follows: in, For all extracted dislocation avalanches, The displacement represents the total plastic deformation, with the severity percentage ranging from 0% to 100%. The temperature / strain rate dependence of determining metal strength based on the intensity ratio includes: Comparing the intensity percentage with 50%, if the intensity percentage is less than 50%, the metallic material exhibits temperature / strain rate dependence.

2. The method for determining the temperature / strain rate dependence of metal strength according to claim 1, characterized in that, The method for determining the stress-strain curve includes: Experimental instruments were used to test micro- and nano-sized metal samples to obtain force-displacement curves, and stress-strain curves were calculated based on the force-displacement curves.

3. The method for determining the temperature / strain rate dependence of metal strength according to claim 1, characterized in that, The background noise of the no-load test includes: Using the same experimental conditions, an unloaded experiment was conducted with the experimental instrument to obtain the time and displacement data of the instrument head, which were then used as the background noise of the instrument.

4. The method for determining the temperature / strain rate dependence of metal strength according to claim 3, characterized in that, The determination of the maximum displacement rate of the experimental instrument includes: The displacement rate at each moment is determined based on time and displacement data, and then the maximum displacement rate is obtained. The expression for displacement rate is as follows: (D n -D n-1 ) / (t n -t n-1 ) Where D is displacement and t is time.

5. The method for determining the temperature / strain rate dependence of metal strength according to claim 1, characterized in that, The determination of the total amount of plastic displacement includes: Calculate the corresponding plastic displacement based on the starting and ending points of each dislocation avalanche, and sum the plastic displacements of all dislocation avalanches to obtain the total plastic displacement corresponding to the total dislocation avalanche.

6. A system for performing the method for determining the temperature / strain rate dependence of metal strength according to any one of claims 1-5, characterized in that, include: The acquisition module is used to acquire the stress-strain curves of micro- and nano-sized metal samples under constant strain rate conditions, as well as the background noise of the no-load experiment. The rate module is used to determine the maximum displacement rate of the experimental instrument used in the experiment based on the background noise, and to serve as the threshold under strain-free jump signal. The dislocation avalanche traversal module is used to traverse the stress-strain curve using a threshold to determine the start and end points of all dislocation avalanches in the nanoscale metal sample. The analysis module is used to determine the total plastic displacement of dislocation avalanches based on the start and end points of the dislocation avalanches, and to determine the intensity ratio of the nanometal sample by combining the total plastic deformation of the nanometal sample experiment. Based on the intensity ratio, the temperature / strain rate dependence of the metal strength is determined.

7. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the method for determining the temperature / strain rate dependence of metal strength as described in any one of claims 1-5 when executing the computer program.

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