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

Abstract

The invention discloses a method and a system for determining temperature / strain rate dependence of metal strength, and belongs to the field of micro-nano technology, the method comprises the following steps: obtaining a compression or tensile stress-strain curve of a micro-nano metal sample and background noise of a no-load experiment; determining the maximum value of the displacement rate of the micro-nano mechanical test instrument according to the background noise and taking the maximum value as a threshold value; traversing the stress-strain curve according to a threshold value, determining starting points and ending points of all dislocation avalanche, determining the shaping displacement total amount of the dislocation avalanche, determining the intensity ratio of the micro-nano metal sample, and further determining the temperature / strain rate dependence of the metal strength; according to the method, whether the intensity has temperature dependence or not can be accurately determined through quantitative analysis by testing a single sample at room temperature and calculating the intensity proportion, so that thin judgment of qualitative analysis and verification of multiple multi-sample experiments are avoided, and the experiment cost such as time and manpower is saved.

Description

Technical Field

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

[0002] Metals with body-centered cubic lattice structures, such as molybdenum, niobium and tungsten, have excellent material properties, such as high-temperature mechanical properties, high thermal stability, excellent creep resistance, high melting point, low plastic / brittle transition temperature and low resistivity. For example, metal body-centered cubic nanobeams have extremely small lattice sizes and excellent mechanical properties and are used in many fields; niobium metal nanowires with high strength and outstanding deformation ability are considered to be important materials for building nanoscale electromechanical devices; single-crystal molybdenum is selected as the gate material of complementary metal oxide semiconductors due to its high thermal stability, high melting point, low resistivity and matching thermal expansion coefficient with silicon lattice. Because of the electrical heating effect, these applications need to serve at different temperatures, so it is important to determine whether the strength of the material changes dramatically with temperature. However, the strength of micro-nano metal materials has a size effect, and materials of corresponding sizes need to be processed for micro-nano mechanical property testing, which cannot be evaluated through performance testing of bulk materials.

[0003] At present, the method for determining whether the strength of micro-nano metal materials is temperature / strain rate dependent is to compare the stress-strain curves obtained by processing micro-nano samples for stretching / compression. This requires multiple sample experiments at various target temperatures and strain rates. This judgment method requires multiple changes in test conditions to perform complex variable temperature and variable rate experiments, which makes the experimental process cumbersome and difficult to operate, and increases the time and labor costs of the experiment. In addition, unlike the experimental tests of macroscopic bulk materials, quantitative mechanical experiments on micro-nano-scale materials face difficulties such as the determination and analysis of tiny mechanical quantities: there are fewer variable temperature micro-nano mechanical testing equipment, a small temperature range, and high costs; the test atmosphere and suitable indenter materials need to be controlled to prevent the material from undergoing chemical changes or reacting with the indenter at high temperatures; the temperature difference between the sample and the indenter takes a lot of time to match well to avoid the influence of thermal drift, etc. Therefore, it is necessary to ensure that the test at high temperature can provide accurate and reliable data through carefully designed experiments and equipment, and the test difficulty is relatively high. Therefore, there is an urgent need for a simple method to determine the degree of change of yield strength or flow stress with temperature and strain rate. Summary of the invention

[0004] In response to 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 determining whether its strength is dependent on temperature and strain rate.

[0005] The present invention is achieved through the following technical solutions: First invention, the present application provides a method for determining the temperature / strain rate dependence of metal strength, comprising the following process: Under the condition of constant strain rate, the stress-strain curve of micro-nano metal sample experiment and the background noise of no-load experiment are obtained; The maximum displacement rate of the micro-nanomechanical system of the experimental instrument is determined according to the background noise, and is used as the threshold value under the non-strain jump signal; The stress-strain curve is traversed by using a threshold value to determine the starting point and the ending point corresponding to all dislocation avalanches of the micro-nano metal sample; The total amount of plastic displacement of the dislocation avalanche is determined according to the starting and ending points of the dislocation avalanche, and the severity ratio of the micro-nano metal sample is determined based on the total plastic deformation of the nanometal sample experiment. The temperature / strain rate dependence of the metal strength is determined based on the severity ratio.

[0006] Preferably, the method for determining the stress-strain curve includes: The force-displacement curve is obtained by using an experimental instrument to experiment on micro-nano metal samples, and the stress-strain curve is calculated based on the force-displacement curve.

[0007] Preferably, the background noise of the no-load experiment includes: Using the same experimental conditions, a no-load experiment was carried out using the experimental instrument to obtain the time and displacement data of the instrument pressure head, which were used as the background noise of the instrument.

[0008] Preferably, the determination of the maximum displacement rate of the experimental instrument includes: Determine the displacement rate at each moment according to the time and displacement data, and then the maximum value of the displacement rate; The expression of displacement rate is as follows: (D n -D n-1 ) / (t n -t n-1 ) Where D is the displacement and t is the time.

[0009] Preferably, the determination of the total amount of shaping displacement includes: The corresponding plastic displacement is calculated according to the starting point and ending point of each dislocation avalanche, and the plastic displacements of all dislocation avalanches are summed to obtain the total plastic displacement corresponding to the total dislocation avalanche.

[0010] Preferably, the calculation method of the plastic displacement of the dislocation avalanche is as follows:

[0011] in, , , and are the displacement and force at the start and end of the displacement jump, respectively. is the theoretical stiffness of the specimen.

[0012] Preferably, the method for determining the potency ratio is as follows:

[0013] in, is the plastic displacement of all extracted dislocation avalanches, is the displacement of the total plastic deformation, and the proportion of plastic deformation ranges from 0% to 100%.

[0014] Preferably, the temperature / strain rate dependence of metal strength is determined according to the severity ratio, including: The severity ratio is compared with 50%. When the severity ratio is less than 50%, the metal material has temperature / strain rate dependence.

[0015] Second invention, the present application provides a system for determining the temperature / strain rate dependence of metal strength, comprising: The acquisition module is used to obtain the stress-strain curve of the micro-nano metal sample experiment and the background noise of the no-load experiment under the condition of constant strain rate; The rate module is used to determine the maximum displacement rate of the experimental instrument used in the experiment according to the background noise, and use it as the threshold value under the strain-free jump signal; A dislocation avalanche traversal module is used to traverse the stress-strain curve using a threshold value to determine the starting and ending points of all dislocation avalanches of the nanometal sample; The analysis module is used to determine the total amount of plastic displacement of the dislocation avalanche according to the starting point and the end point of the dislocation avalanche, and to determine the severity ratio of the nanometal sample in combination with the total plastic deformation of the nanometal sample experiment, and to determine the temperature / strain rate dependence of the metal strength according to the severity ratio.

[0016] The third invention, the present application provides an electronic device, including: Memory for storing computer programs; A processor is used to implement the steps of the method for determining the temperature / strain rate dependence of metal strength when executing the computer program.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention discloses a method for determining the temperature / strain rate dependence of metal strength. By directly observing the dislocation avalanche characteristics on the stress-strain curve and combining the judgment index of the severity ratio, the temperature / strain rate dependence of metal strength is efficiently determined by the single sample method. By introducing the severity ratio, that is, the proportion of the plastic deformation generated by the dislocation avalanche to the total plastic deformation, the contribution of the dislocation avalanche to the plastic deformation of the material can be quantitatively evaluated. This not only provides a specific numerical basis for judging the strength dependence of the material, but also provides a possibility for further studying the dislocation avalanche mechanism and its relationship with material properties. Secondly, the method is based on the physical mechanism of dislocation movement in body-centered cubic metals, especially the dominant role of screw dislocations in plastic deformation, and the relationship between dislocation avalanche and the movement rate of screw dislocations. This judgment method based on physical mechanisms is more scientific and convincing, and can provide a deeper understanding of the deformation behavior of the material. In addition, the method judges the temperature / strain rate dependence of metal strength by directly observing the dislocation avalanche characteristics on the stress-strain curve, avoiding the complex physical models and indirect measurement methods involved in traditional methods. The strain jump caused by dislocation avalanche in micron / submicron scale materials is intuitive and measurable, thus improving the accuracy and reliability of judgment.

[0018] The present 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 above-mentioned method for determining the temperature / strain rate dependence of metal strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 A force-displacement curve diagram of an example of the present invention; Figure 2 is a threshold determination diagram under a strain-free jump signal according to Example 1 of the present invention; Figure 3 Extracting a strain jump diagram according to a threshold value in Example 1 of the present invention; Figure 4 This is an example diagram of strain jump in Example 1 of the present invention; Figure 5 This is a time-displacement rate diagram of the microcolumn of Example 2 of the present invention; Figure 5 a is a threshold determination diagram under strain-free sudden jump signal of Example 2; Figure 5 b is a strain jump diagram extracted according to the threshold value in Example 2; Figure 6 The room temperature compressive stress-strain curve and the change diagram of yield strength with temperature of the microcolumn of the present invention are shown; Figure 6 a is the room temperature compressive stress-strain curve of 1000 nm and 3500 nm microcolumns of the present invention; Figure 6 b is a graph showing the change in yield strength of 1000 nm and 3500 nm microcolumns of the present invention with temperature; Figure 7 The compressive stress-strain curves of the 1000nm and 3500nm microcolumns of the present invention at different temperatures; Figure 7 a is the compressive stress-strain curve of the 1000 nm microcolumn of the present invention at different temperatures; Figure 7 b is the compressive stress-strain curve of the 3500 nm microcolumn of the present invention at different temperatures; Figure 8 The room temperature compressive stress-strain curve of the microcolumn of the present invention and the change diagram of the yield strength with the strain rate; Figure 8 a is the room temperature compressive stress-strain curve of 1000 nm and 1500 nm microcolumns of the present invention; Figure 8 b is a graph showing the variation of the yield strength of the 1000nm and 1500nm microcolumns of the present invention with the strain rate.

[0021] Fig. 9 The compressive stress-strain curves of the 1000nm and 1500nm micropillars of the present invention at different strain rates; Fig. 9 a is the compressive stress-strain curve of the 1000 nm microcolumn of the present invention at different strain rates; Fig. 9 b is the compressive stress-strain curve of the 1500 nm microcolumn of the present invention at different strain rates. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0024] The principle that the strength of body-centered cubic metals has a strong temperature / strain rate dependence is that the dislocations inside body-centered cubic metals are non-planar core structures and therefore have complex dislocation core structures, which leads to large Peierls stress. Under low temperature conditions, the movement of screw dislocations is mainly carried out through the formation of kink pairs. This process is mainly controlled by thermally activated screw dislocations, which gives body-centered cubic metals a strong temperature and strain rate dependence; with the increase of temperature and strain rate, thermal activation reduces the sliding stress of screw dislocations, and the flow stress of body-centered cubic metals drops sharply until it reaches the athermal transition temperature. Therefore, the essence of whether body-centered cubic metals have temperature and strain rate dependence is whether plastic deformation is dominated by screw dislocations.

[0025] During the plastic deformation of metal crystals, long-range interactions occur between dislocations, and hundreds or thousands of dislocations move at a high speed at the same time in an instant, which is called dislocation avalanche. For macroscopic materials, the displacement produced by dislocation avalanche is very small compared to the material size and cannot be directly detected. For micron / submicron scale materials, the displacement produced by dislocation avalanche is close to the order of magnitude of the material size, which will produce a sharp strain jump on the stress-strain curve and can be directly measured. This application will use this basic feature to determine whether a metal material has temperature / strain rate sensitivity.

[0026] The detection principle of the present application is that if the strength of a body-centered cubic metal has a strong temperature / strain rate dependence, then its plastic deformation should be mainly controlled by screw dislocations, and the movement rate of screw dislocations depends on the thermal activation strength. At the same temperature, the average movement rate of screw dislocations is a constant, and rapid movement cannot occur, and dislocation avalanche cannot occur. On the contrary, if obvious dislocation avalanche characteristics are observed on the stress-strain curve, it means that the plastic deformation of the body-centered cubic metal is not dominated by screw dislocations, so its strength should not depend on temperature and strain rate. Based on this principle proposed by the present invention, the single specimen method is used to test whether the deformation of a single sample at room temperature is dominated by screw dislocations, so as to determine whether the strength of the material is dependent on temperature and strain rate.

[0027] The method for determining the temperature / strain rate dependence of metal strength in the present application is based on the fact that dislocation avalanche appears as a strong strain jump on the stress-strain curve. The severity ratio is introduced, that is, the proportion of plastic deformation generated by dislocation avalanche to the total plastic deformation. By calculating the severity 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.

[0028] A method for determining the temperature / strain rate dependence of metal strength, comprising the following steps: Step 1: Under the condition of constant strain rate, obtain the stress-strain curve of the micro-nano metal sample experiment.

[0029] Micro-nano metals use technologies such as focused ion beam or chemical etching to prepare metal specimens for mechanical testing.

[0030] Under room temperature conditions, compression / stretching experiments are carried out on micro-nano metals to obtain the force-displacement relationship curve of the metal sample.

[0031] Analyzing the force-displacement curve, we can see the jagged deformation curve caused by the dislocation avalanche, see Figure 1 .

[0032] Step 2: Under the same experimental conditions as step 1, obtain the background noise of the no-load experiment, determine the maximum value of the displacement rate based on the background noise, and use it as the threshold value under the strain-free jump signal.

[0033] Using the same experimental parameters as step 1, a no-load experiment is performed using a micro-nanomechanics instrument to obtain the time and displacement data of the pressure head of the experimental instrument. The time and displacement data are the background noise.

[0034] The time and displacement data are recorded as [t1, t2...t n ] and [D1,D2...D n ], determine the displacement rate at each moment according to the time and displacement data, and take the maximum displacement rate as the threshold value under the strain-free jump signal, such as Figure 2 shown.

[0035] The displacement rate is calculated as follows: (D n -D n-1 ) / (t n -t n-1 ) Step 3: Use the threshold value to traverse the stress-strain curve and determine the starting point and ending point of all dislocation avalanches.

[0036] The dislocation avalanche is extracted from the displacement rate-time signal according to the maximum displacement rate of the background noise, see Figure 3, where the signals greater than the threshold are from dislocation avalanches. The specific operation is to retrieve data from t=0, that is, when the displacement rate is greater than the threshold, it can be determined that a dislocation avalanche has occurred. At this time, the displacement and force are recorded as D s and F s , and then when the displacement rate is less than the threshold, the dislocation avalanche ends, and the displacement and force are recorded as D e and F e .

[0037] By traversing the entire force-displacement curve, the displacement and force at the occurrence and end of all dislocation avalanches can be recorded. Figure 4 The starting point and ending point of a certain strain jump extracted are given on the force-displacement curve.

[0038] Step 4: Determine the plastic displacement of each dislocation avalanche according to the starting point and the ending point of the dislocation avalanche, and sum up to obtain the total plastic displacement of all dislocation avalanches.

[0039] The size of the plastic displacement caused by the dislocation avalanche can be calculated through the starting point and end point of the dislocation avalanche. The expression is as follows:

[0040] in, , , and are the displacement and force at the start and end of the displacement jump, respectively. is the theoretical stiffness of the specimen.

[0041] Step 5: Determine the severity ratio of the micro-nano metal sample based on the total amount of plastic displacement of the dislocation avalanche and the total plastic deformation of the micro-nano metal sample.

[0042] The severity ratio is defined as the ratio of the plastic deformation caused by dislocation avalanche to the total plastic deformation; The total plastic deformation is the total displacement deformation of the micro-nano metal specimen from the beginning of yielding to the end of the experiment during the experiment.

[0043] The expression of the intensity ratio is as follows:

[0044] in, is the plastic displacement of all extracted dislocation avalanches, is the displacement of the total plastic deformation, and the proportion of plastic deformation ranges from 0% to 100%.

[0045] Step 6. Compare the sintering fraction to 50% to determine if the metal has temperature and strain rate dependence.

[0046] The strength ratio measured at room temperature is used to determine whether the strength is temperature and strain rate dependent, with 50% as the limit: If the proportion of severe deformation is >50%, it means that screw dislocation does not dominate plastic deformation at this time, and it can be determined that the material strength has no strong dependence on temperature / strain rate; If the severity ratio is <50%, it means that screw dislocations dominate plastic deformation at this time, so the material strength has a strong dependence on temperature / strain rate.

[0047] This method replaces complex variable temperature and variable rate experiments. Given that micron / submicron scale materials need to serve at different temperatures, in order to verify whether the material strength is temperature dependent, it is necessary to test under multiple different temperature conditions. Now a parameter that reflects the law of dislocation movement is proposed-the intensity ratio. By testing a single sample at room temperature, calculating this value, it is possible to accurately confirm whether the strength is temperature dependent through quantitative analysis, thereby avoiding the simple judgment of qualitative analysis and the verification of multiple multi-sample experiments to save time, manpower and other experimental costs. The same method is also applicable to determining strain rate dependence.

[0048] Example 1 Taking single crystal molybdenum microcolumns with diameters of 1000nm and 3500nm as examples, the above-mentioned method for determining the temperature / strain rate dependence of metal strength is used to determine whether the single crystal molybdenum microcolumns with diameters of 1000nm and 3500nm have temperature dependence, as follows: Step 1: Compress single-crystal Mo micropillars with diameters of 1000 nm and 3500 nm at room temperature at a strain rate of 2×10 - 3 s -1 The stress-strain curve is shown in the attached figure. Figure 6 a.

[0049] Step 2, calculate the potency ratio: For a 1000 nm microcolumn, the formula (D n -D n-1 ) / (t n -t n-1 ) calculates the displacement rate of the test sample, and then extracts the dislocation avalanche from the displacement rate-time signal according to the threshold value, which can be seen in Figure 2 and Figure 3 , where the signals greater than the threshold are from dislocation avalanches. After determining the threshold, all strain jumps are extracted, and the formula is used The summation is calculated to obtain ∑X=550nm, and D is calculated from the original data. p =625nm, so the ratio of the intensity of the 1000nm microcolumn at room temperature is =88%. For the 3500nm microcolumn, the same calculation steps can be used to obtain the proportion of toxicity at room temperature W=1.2%, Step 3, at room temperature, the proportion of microcolumns with a diameter of 1000nm is W = 88%>50%, and the microcolumns at this diameter have undergone severe deformation, and the yield strength has no temperature dependence; the proportion of microcolumns with a diameter of 3500nm is W = 1.2%<50%, and it can be judged that the microcolumns of this diameter have undergone warm deformation, that is, the screw dislocation dominates the plastic deformation, and its strength will have temperature dependence. Its temperature dependence is as follows Figure 6 b.

[0050] Step 4, verify the above results of 1000nm molybdenum microcolumns.

[0051] Four molybdenum microcolumns with a diameter of 1000 nm were processed and heated to 25°C, 70°C, 140°C and 200°C in a vacuum environment. Compression tests were performed to obtain the strength at different temperatures. Figure 7 In a, it can be seen that the material strength does not change with temperature, which is consistent with the judgment result of the single specimen method.

[0052] Step 5, verify the above results of 3500nm molybdenum microcolumns.

[0053] Four molybdenum micropillars with a diameter of 3500nm were processed and heated to 25℃, 70℃, 140℃ and 200℃ in a vacuum environment. Compression tests were performed to obtain the strength at different temperatures. Figure 7 In b, it can be seen that the material strength decreases rapidly with increasing temperature and has a strong temperature dependence, which is consistent with the judgment result of the single specimen method.

[0054] Example 2 Taking single crystal molybdenum microcolumns with diameters of 1000nm and 1500nm as examples, the above-mentioned method for determining the temperature / strain rate dependence of metal strength is used to determine whether the single crystal molybdenum microcolumns with diameters of 1000nm and 1500nm have strain rate dependence, as follows: Step 1: Compress single-crystal Mo micropillars with diameters of 1000 nm and 1500 nm at room temperature at a strain rate of 2×10 - 3 s -1 The stress-strain curve is shown in the attached figure. Figure 8 a.

[0055] Step 2: Calculate the intensity ratio: For a 1000 nm microcolumn, calculate the cumulative probability distribution of displacement rate, and extract all strain jumps after determining the threshold, as shown in the attached figure. Figure 5 , the microcolumn is the same microcolumn as in Example 1, the proportion of =88%. For the 1500nm microcolumn, the same calculation steps can be used to obtain the potency ratio W=31% at room temperature.

[0056] Step 3, at room temperature, the proportion of microcolumns with a diameter of 1000 nm is W = 88%>50%. According to the present invention, microcolumns with this diameter have undergone severe deformation, and the yield strength has no strain rate dependence; the proportion of microcolumns with a diameter of 1500 nm is W = 31%<50%. It can be judged that microcolumns with this diameter undergo warm deformation, that is, screw dislocations dominate plastic deformation, and their strength will have strain rate dependence. Its dependence is as shown in the attached figure. Figure 8 b.

[0057] Step 4, verify the above results of 1000nm molybdenum microcolumns.

[0058] Three molybdenum microcolumns with a diameter of 1000nm were processed and subjected to compression 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. Fig. 9 In 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 specimen method.

[0059] Step 5, verify the above results of 1500nm molybdenum microcolumns.

[0060] Three molybdenum microcolumns with a diameter of 1500nm were processed and subjected to compression 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. Fig. 9 In b, it can be seen that the material strength decreases greatly with the decrease of strain rate, and has a strong strain rate dependence, which is consistent with the judgment result of the single specimen method.

[0061] Based on the above method for determining the temperature / strain rate dependence of metal strength, the present application also provides a system for determining the temperature / strain rate dependence of metal strength, including: The acquisition module is used to obtain the stress-strain curve of the micro-nano metal sample compression experiment and the background noise of the compression no-load experiment under the condition of constant strain rate; A rate module is used to determine the maximum displacement rate of the compression test instrument used in the compression test according to the background noise, and use it as a threshold value under the condition of no strain jump signal; A dislocation avalanche traversal module, which is used to traverse the stress-strain curve using a threshold value to determine the starting and ending points of all dislocation avalanches of the micro-nano metal sample; The analysis module is used to determine the total amount of plastic displacement of the dislocation avalanche according to the starting point and the end point of the dislocation avalanche, and to determine the severity ratio of the nanometal sample in combination with the total plastic deformation of the compression test of the nanometal sample, and to determine the temperature / strain rate dependence of the metal strength according to the severity ratio.

[0062] It should be noted that in the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of each module is only a logical function division. There may be other division methods in actual implementation. For example, multiple modules can be combined or integrated into another device, or some features can be ignored or not executed. The module described as a separate component may or may not be physically separated. The component displayed as a module may be a physical unit or multiple physical units, that is, it may be located in one place, or it may be distributed in multiple different places. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0063] In addition, each module in each embodiment of the present invention may be integrated into a processing unit, each module may exist physically separately, or two or more modules may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of a software functional unit.

[0064] An electronic device provided in an embodiment of the present application includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the steps of the method for determining the temperature / strain rate dependence of metal strength as described in any of the above embodiments are implemented.

[0065] An embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the steps of the method for determining the temperature / strain rate dependence of metal strength as described in any of the above embodiments are implemented.

[0066] For the description of the relevant parts of the system for determining the temperature / strain rate dependence of metal strength, the electronic device, and the computer-readable storage medium provided in the embodiments of the present application, please refer to the detailed description of the corresponding parts in the method for determining the temperature / strain rate dependence of metal strength provided in the embodiments of the present application, which will not be repeated here. In addition, the parts of the above-mentioned technical solutions provided in the embodiments of the present application that are consistent with the implementation principles of the corresponding technical solutions in the prior art are not described in detail to avoid excessive elaboration.

[0067] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for determining the temperature / strain rate dependence of metal strength, characterized in that: The process includes: Under the condition of constant strain rate, the stress-strain curve of micro-nano metal sample experiment and the background noise of no-load experiment are obtained; The maximum displacement rate of the micro-nanomechanical system of the experimental instrument is determined according to the background noise, and is used as the threshold value under the non-strain jump signal; The stress-strain curve is traversed by using a threshold value to determine the starting point and the ending point corresponding to all dislocation avalanches of the micro-nano metal sample; The total amount of plastic displacement of the dislocation avalanche is determined according to the starting and ending points of the dislocation avalanche, and the severity ratio of the micro-nano metal sample is determined based on the total plastic deformation of the nanometal sample experiment. The temperature / strain rate dependence of the metal strength is determined based on the severity ratio.

2. A 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 comprises: The force-displacement curve is obtained by using an experimental instrument to experiment on micro-nano metal samples, and the stress-strain curve is calculated based on the force-displacement curve.

3. A 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 experiment includes: Using the same experimental conditions, a no-load experiment was carried out using the experimental instrument to obtain the time and displacement data of the instrument pressure head, which were used as the background noise of the instrument.

4. A 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 apparatus includes: Determine the displacement rate at each moment according to the time and displacement data, and then the maximum value of the displacement rate; The expression of displacement rate is as follows: (D n -D n-1 ) / (t n -t n-1 ) Where D is the displacement and t is the time.

5. A 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 shaping displacement includes: The corresponding plastic displacement is calculated according to the starting point and ending point of each dislocation avalanche, and the plastic displacements of all dislocation avalanches are summed to obtain the total plastic displacement corresponding to the total dislocation avalanche.

6. A method for determining the temperature / strain rate dependence of metal strength according to claim 5, characterized in that: The calculation method of the plastic displacement of the dislocation avalanche is as follows: in, , , and are the displacement and force at the start and end of the displacement jump, respectively. is the theoretical stiffness of the specimen.

7. A method for determining the temperature / strain rate dependence of metal strength according to claim 1, characterized in that: The method for determining the potency ratio is as follows: in, is the plastic displacement of all extracted dislocation avalanches, is the displacement of the total plastic deformation, and the proportion of plastic deformation ranges from 0% to 100%.

8. A method for determining the temperature / strain rate dependence of metal strength according to claim 1, characterized in that: The temperature / strain rate dependence of metal strength determined according to the heat ratio includes: The severity ratio is compared with 50%. When the severity ratio is less than 50%, the metal material has temperature / strain rate dependence.

9. A system for determining the temperature / strain rate dependence of metal strength, characterized in that include: The acquisition module is used to obtain the stress-strain curve of the micro-nano metal sample experiment and the background noise of the no-load experiment under the condition of constant strain rate; The rate module is used to determine the maximum displacement rate of the experimental instrument used in the experiment according to the background noise, and use it as the threshold value under the strain-free jump signal; A dislocation avalanche traversal module is used to traverse the stress-strain curve using a threshold value to determine the starting and ending points of all dislocation avalanches of the nanometal sample; The analysis module is used to determine the total amount of plastic displacement of the dislocation avalanche according to the starting point and the end point of the dislocation avalanche, and to determine the severity ratio of the nanometal sample in combination with the total plastic deformation of the nanometal sample experiment, and to determine the temperature / strain rate dependence of the metal strength according to the severity ratio.

10. An electronic device, characterized in that: include: Memory for storing computer programs; A processor, configured to implement the steps of the method for determining the temperature / strain rate dependence of metal strength according to any one of claims 1 to 8 when executing the computer program.

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