A micro-nano impact indentation test device and method based on cyclic refrigeration

Abstract

A micro-nano impact indentation test device and method based on cyclic refrigeration, which relates to the technical field of material property testing, includes an indenter and a stage for low-temperature micro-nano impact indentation testing, and a refrigeration device for cooling the indenter and the stage. Among them, the refrigeration device uses an embedded flow channel to cool the indenter and the stage respectively. A connecting cold conduction wire is arranged between the indenter and the stage, and a refrigeration balancer in contact with the cold conduction wire. The cold conduction wire and the refrigeration balancer jointly stabilize the temperatures of the indenter and the stage at a common temperature point. When performing low-temperature micro-nano impact indentation testing, the present invention can quickly balance the temperature difference between the sample and the test head due to the difference in refrigeration degree, eliminate the influence of temperature drift on the test accuracy, and ensure the accuracy of the low-temperature micro-nano impact indentation test results.

Description

Technical Field

[0001] The present invention relates to the technical field of material property testing, and particularly to a micro-nano impact indentation testing device and method based on cyclic refrigeration. Background Art

[0002] Impact indentation technology is an experimental method for measuring the local mechanical properties of materials under high-speed dynamic loads, especially suitable for studying the behavior of materials under high strain rate conditions, such as in fields like automotive collisions, space launches, supersonic aircraft, high-speed forming processes, and military protection. The strain rate upper limit of traditional static or quasi-static indentation testing technology is relatively low, usually not exceeding 10 -1 s -1 and it is difficult to meet the evaluation requirements for dynamic responses. Therefore, impact indentation technology has emerged, which can provide a higher strain rate range, usually up to 10 3 s -1 or higher, to simulate the dynamic load effects under real conditions. Traditional impact indentation technology usually focuses on the dynamic mechanical behavior at normal temperature or higher temperatures, but at low temperatures, the physical and mechanical properties of materials will change significantly, such as increased brittleness and reduced toughness, which is crucial for the application of materials in extreme environments. Accordingly, the present invention aims to provide a fast, efficient, and stable low-temperature loading environment for a micro-nano impact indenter tester to obtain the service performance of materials under the extreme conditions of the coupling of impact indentation and low-temperature environment.

[0003] In the field of material micro-mechanical property testing, many scholars have studied low-temperature static nano-indentation devices and achieved certain results, but there is less research on the low-temperature loading of micro-nano impact indentation testing devices. Currently, most of the refrigeration systems for low-temperature nano-indentation are atmosphere refrigeration, which is combined with commercial liquid nitrogen dewars and requires large and heavy atmosphere chambers. It is difficult to integrate various in-situ monitoring means, and has high requirements for the placement site, specimen size, and energy consumption. And it is often difficult to achieve precise simultaneous cooling of the indenter and the sample, and the temperature difference between the indenter and the sample will cause the "temperature drift" phenomenon, restricting the test accuracy.

[0004] In summary, aiming at the problem of the lack of micro-mechanical behavior testing means for functional materials and structural materials under the coupling action of impact indentation and low-temperature environment, constructing the service performance conditions of materials under the extreme conditions of the coupling of impact indentation and low-temperature environment is helpful for the further development of fields such as energy power and aerospace. Therefore, it is very necessary to design and develop a refrigeration device applicable to a micro-nano impact indenter tester that can achieve continuous temperature change, cooperative refrigeration, and is easy to integrate with various monitoring means. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a micro-nano impact indentation test device and method based on cyclic refrigeration. By separately cyclic refrigerating the indenter and the stage for impact indentation test, accurate observation and research on the microscopic impact mechanical properties of materials under low-temperature extreme conditions are realized.

[0006] To solve the above at least one technical problem, the technical solution provided by the present invention is:

[0007] Provide a micro-nano impact indentation test device based on cyclic refrigeration, including a linear motor, a driving platform, a piezoelectric stack, an indenter, an infrared thermal imaging component, a stage, a sliding table, and a refrigeration device. Among them,

[0008] The driving platform is arranged on the linear motor and can move towards the stage under the drive of the linear motor; a hinge base is also arranged on the driving platform, and a connected piezoelectric stack and indenter are arranged on the hinge base. A diamond indenter is arranged at the tip of the indenter, so that the indenter and the diamond indenter can move towards the stage under the push of the piezoelectric stack. A force sensor is arranged between the indenter and the piezoelectric stack to obtain the driving force exerted by the piezoelectric stack on the indenter;

[0009] The stage is arranged on the sliding table. A clamp is arranged on the surface of the stage facing the indenter. The clamp can stably clamp the sample to be tested, and the diamond indenter can move to contact the sample to be tested. The stage can move along the sliding table to make the sample to be tested directly opposite the tip of the indenter;

[0010] The infrared thermal imaging component is arranged on one side of the indenter, and its infrared thermal imaging range includes the force sensor, the indenter, the sample to be tested, and the stage;

[0011] The refrigeration device is arranged on one side of the indenter. It is connected with a micro-channel in the indenter buried through an indenter inlet cold pipe and an indenter outlet cold pipe to form a circulation pipeline, so that the refrigeration device can circulate the refrigeration medium inside the indenter; the refrigeration device is also connected with a micro-channel in the stage buried through a stage inlet cold pipe and a stage outlet cold pipe to form a circulation pipeline, so that the refrigeration device can circulate the refrigeration medium inside the stage;

[0012] A heat conduction wire is also arranged between the indenter and the stage. One end of the heat conduction wire is connected to the position close to the diamond indenter, and the other end is connected to the position on the stage close to the sample to be tested, so that heat exchange can be carried out between the indenter and the stage through the heat conduction wire.

[0013] In an embodiment of the present invention, a refrigeration balancer is provided below the pressure rod. The refrigeration balancer includes an outer frame, a cold conduction plate, a limit hanging buckle, and a cold storage container. The outer frame is a hollow container with at least one set of side openings. At least a part of its top surface is a cold conduction plate. Above the top surface, a limit hanging buckle is provided in close contact with the cold conduction plate. The limit hanging buckle can clamp the cold conduction wire on the top surface of the outer frame to keep in contact with the cold conduction plate.

[0014] A cold storage container that completely fills its internal space is detachably arranged inside the outer frame. At least one side of the cold storage container is a transparent observation window, and the observation window is located at the side opening of the outer frame. The top of the cold storage container is a cold conduction top plate. The inside of the cold storage container is filled with a phase change material, so that the phase change material can sequentially perform heat exchange with the cold conduction wire through the cold conduction top plate and the cold conduction plate.

[0015] Further, a camera assembly is provided on one side of the refrigeration balancer. The imaging area of the camera assembly includes the entire observation window.

[0016] Further, the materials of the cold conduction wire, the cold conduction plate, and the cold conduction top plate are copper.

[0017] In an embodiment of the present invention, a pressure rod thermocouple is provided on the pressure rod near the diamond indenter, and a stage thermocouple is provided on the stage near the sample to be measured. The distances between the pressure rod thermocouple and the diamond indenter and between the stage thermocouple and the sample to be measured are both within 0.5 mm.

[0018] In an embodiment of the present invention, an insulating baffle for blocking low temperature conduction to the force sensor is provided between the force sensor and the pressure rod.

[0019] In an embodiment of the present invention, heat insulation materials are coated on the surfaces of the pressure rod inlet cold tube, the pressure rod outlet cold tube, the stage inlet cold tube, and the stage outlet cold tube.

[0020] In an embodiment of the present invention, a protective gas channel capable of spraying protective gas towards the hinge base is further provided on the slide table.

[0021] In an embodiment of the present invention, the slide table is a single-degree-of-freedom sliding member in the up and down direction.

[0022] In addition, the present invention also provides a micro-nano impact indentation test method based on cyclic refrigeration. Using the above device for testing, it includes the following steps:

[0023] Step S1: Assemble the refrigeration pipeline according to the device, fix the sample to be measured on the stage, install a diamond indenter on the pressure rod, and adjust the stage and the pressure rod so that the positions of the diamond indenter and the sample to be measured correspond.

[0024] Step S2: Clamp the heat conduction wire in the limit hanger of the refrigeration balancer, keep it in contact with the heat conduction plate, fill the phase change material corresponding to the experimental temperature in the cold storage container according to the experimental requirements, and pre-cool the phase change material at the experimental temperature;

[0025] Step S3: Output protective gas through the protective gas channel, set the infrared thermal imaging component and the camera component to the working state, start the refrigeration device to perform cyclic refrigeration on the indenter and the stage respectively until the experimental temperature is reached, and place the cold storage container filled with the pre-cooled phase change material in the refrigeration balancer;

[0026] Step S4: After observing that the indenter and the stage are stable at the experimental temperature, control components such as the driving platform and the piezoelectric stack to perform a low-temperature impact indentation experiment, and collect data related to the impact indentation experiment.

[0027] The technical effects achieved by the present invention are as follows:

[0028] 1. The present invention can perform micro-nano impact indentation tests under low-temperature conditions. It uses an embedded micro-channel method to cool the test sample and the test head simultaneously, and a heat conduction wire in contact with the refrigeration balancer is arranged between the sample and the test head. Bidirectional cooling can be implemented between the sample and the test head through the refrigeration balancer and the heat conduction wire at the experimental temperature, so that the temperature between the sample and the test head can be stably maintained at the experimental temperature, thereby quickly balancing the temperature difference between the sample and the test head due to different degrees of refrigeration, eliminating the influence of temperature drift on the test accuracy, and making the test results more representative.

[0029] 2. The present invention can adjust the output power of the refrigeration device in real time according to the information fed back by the thermocouple and the thermal imaging component to achieve continuous and adjustable temperature. The entire experimental device has a simple structure, a compact layout, does not require an atmosphere refrigeration chamber, and has a high degree of integration, providing effective support for revealing the microscopic failure mechanism and performance evolution law of materials under low-temperature impact conditions. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0031] Figure 1 is the axonometric schematic diagram of the whole of the present invention;

[0032] Figure 2 is the axonometric schematic diagram of the indenter part in the present invention;

[0033] Figure 3 is an axonometric schematic diagram of the stage part in the present invention;

[0034] Figure 4 is an axonometric schematic diagram of the refrigeration balancer in the present invention;

[0035] Figure 5 is a sectional view of the refrigeration balancer in the present invention;

[0036] Figure 6 is a perspective view of the pressure bar in the present invention;

[0037] Figure 7 is a sectional view of the pressure bar in the present invention;

[0038] Figure 8 is a perspective view of the stage in the present invention;

[0039] Figure 9 is a sectional view of the stage in the present invention;

[0040] In the figure: 1 - linear motor, 2 - drive platform, 3 - hinge base, 4 - piezoelectric stack, 5 - force sensor, 6 - cold insulation baffle, 7 - pressure bar microchannel, 71 - pressure bar inlet cold tube, 72 - pressure bar outlet cold tube, 8 - pressure bar, 9 - pressure bar thermocouple, 10 - diamond indenter, 11 - infrared thermal imaging component, 12 - heat conduction wire, 13 - stage thermocouple, 14 - sample to be measured, 15 - fixture, 16 - protective gas channel, 17 - stage, 18 - stage microchannel, 181 - stage inlet cold tube, 182 - stage outlet cold tube, 19 - sliding table, 20 - refrigeration device, 21 - refrigeration balancer, 22 - camera component, 211 - outer frame, 212 - heat conduction plate, 213 - limit buckle, 214 - cold storage container, 215 - observation window, 216 - heat conduction top plate, 217 - phase change material. Specific Embodiments

[0041] The present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings.

[0042] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention claimed, but merely represents selected embodiments of the present invention.

[0043] Embodiment:

[0044] A micro-nano impact indentation test device based on cyclic refrigeration in the present invention mainly includes a linear motor 1, a driving platform 2, a piezoelectric stack 4, a pressure bar 8, an infrared thermal imaging component 11, a stage 17, a slide table 19, and a refrigeration device 20. Among them, the driving platform 2 is arranged on the linear motor 1 and can move towards the stage 17 under the drive of the linear motor 1. Under the action of the linear motor 1, it drives the components on the driving platform 2 as shown in Figure 2 to move as a whole along the displacement output direction of the linear motor 1.

[0045] In Figure 2 , it can also be seen that a hinge base 3 is further arranged on the driving platform 2. A piezoelectric stack 4 and a pressure bar 8 are connected to the hinge base 3. A diamond indenter 10 is arranged at the tip of the pressure bar 8, so that the pressure bar 8 and the diamond indenter 10 can move towards the stage 17 under the push of the piezoelectric stack 4. A force sensor 5 is arranged between the pressure bar 8 and the piezoelectric stack 4 to obtain the driving force exerted by the piezoelectric stack 4 on the pressure bar 8. The structure of this part can refer to the relevant description of the electromagnetic-piezoelectric coupling impact module in Chinese Patent CN118111838A. The main working process is that when the driving platform 2 drives the hinge base 3 to move to the test position as a whole, the piezoelectric stack 4 can further provide an "electromagnetic-piezoelectric" coupling impact to the pressure bar 8, so that the diamond indenter 10 at its tip generates an indentation on the surface of the sample to be tested 14, realizing the impact indentation performance test.

[0046] Referring to Figure 3 , the stage 17 is arranged on the slide table 19. A fixture 15 is arranged on the surface of the stage 17 facing the pressure bar 8. The fixture 15 can stably clamp the sample to be tested 14, and the diamond indenter 10 can move to contact the sample to be tested 14. The stage 17 can move along the slide table 19 to make the sample to be tested 14 directly opposite the tip of the pressure bar 8. In this embodiment, the slide table 19 is a single-degree-of-freedom sliding part in the up and down direction, that is, the stage 17 moves up and down along the slide table 19, and the contact position between the sample to be tested 14 and the diamond indenter 10 can be adjusted accordingly. The fixture 15 can refer to the conventional planar clamping structure in the prior art. When an experiment needs to be carried out, the sample plate to be tested 14 is arranged on the fixture 15, and the diamond indenter 10 is moved to a position close enough to the sample to be tested 14.

[0047] In this embodiment, a protective gas channel 16 capable of spraying protective gas towards the hinge base 3 is further provided on the sliding table 19. Since the impact indentation test environment tracked by the present invention is a low-temperature test, it is likely to cause condensation of moisture in the environment and interfere with the test process. Therefore, the protective gas channel 16 is provided to spray protective gas towards the test position, forming a low-moisture atmosphere in the experimental area by discharging the gas with a high water content in the experimental area. The usage mode of the protective gas channel 16 can also refer to the description of the nitrogen generation module in Chinese Patent CN118111838A, that is, directly connecting it to a protective gas source and supplying and stopping the protective gas as needed. Therefore, the protective gas in the present invention can also be nitrogen. In addition, the application environment of the experimental device in the present invention can be divided into a closed type and an open type. The usage mode of the closed type can also refer to the above-mentioned Chinese patent. Its gas injection method is to inject the protective gas until the closed box where the device is located is full, discharging all the high-water-content gases to avoid interference caused by moisture condensation. When the device in the present invention is used in an open type for experiments, it is necessary to adjust the flow rate generated by the protective gas channel 16 to generate an air curtain at the part between the pressure bar 8 and the stage 17 and at the position where the force sensor 5 is located.

[0048] See Figure 1 , the infrared thermal imaging component 11 is arranged on one side of the pressure bar 8, and its infrared thermal imaging range includes the force sensor 5, the pressure bar 8, the sample to be tested 14, and the stage 17. The function of the infrared thermal imaging component 11 is to uniformly monitor the temperature change during the experiment. It can adopt common infrared monitoring devices in the field such as infrared cameras. Its monitoring range should include components such as the force sensor 5, the pressure bar 8, the sample to be tested 14, and the stage 17 that may be affected by temperature and cause performance changes. The data collected can be connected to an external host or an electronic control module, and the connection method can refer to the setting method of the host and the electronic control module in Chinese Patent CN118111838A. In addition, all devices or electronic components that need to implement electronic control or data collection in this device can also be connected to an external host or an electronic control module through electrical connection. Such electronic control methods are not limited to the control of the infrared thermal imaging component 11.

[0049] See Figure 1 , the refrigeration device 20 is arranged on one side of the pressure bar 8. It forms a circulation pipeline with the pressure bar micro-channel 7 buried inside the pressure bar 8 through the pressure bar inlet cold pipe 71 and the pressure bar outlet cold pipe 72, enabling the refrigeration device 20 to circulate the refrigeration medium inside the pressure bar 8. The refrigeration device 20 also forms a circulation pipeline with the stage micro-channel 18 buried inside the stage 17 through the stage inlet cold pipe 181 and the stage outlet cold pipe 182, enabling the refrigeration device 20 to circulate the refrigeration medium inside the stage 17. By Figure 6 , Figure 7It can be seen that a microchannel 7 is provided inside the pressure bar 8. The arrangement of the microchannel 7 in the pressure bar can refer to the coiled dielectric heat conduction tube in the prior art. It is respectively connected to the cold tube 71 at the inlet of the pressure bar and the cold tube 72 at the outlet of the pressure bar to form a heat conduction cycle structure. Thus, a heat conduction medium can be circulated into the microchannel 7 in the pressure bar through the refrigeration device 20. Combining Figure 2 It can be further seen that the cold tube 71 at the inlet of the pressure bar is connected to the microchannel 7 in the pressure bar on the side closer to the diamond indenter 10. That is, the circulation mode of the heat conduction medium should enter the microchannel 7 in the pressure bar from the cold tube 71 at the inlet of the pressure bar, and then the heat conduction medium after heat exchange is discharged from the cold tube 72 at the outlet of the pressure bar, so as to preferentially ensure the temperature of the stable diamond indenter 10. At the same time, in the present invention, tests under low-temperature conditions need to be realized. Therefore, the heat conduction medium should be a cooling medium, and the circulation of the cooling medium should run through the whole test process, so as to keep the pressure bar 8 under low-temperature conditions throughout the process; similarly, Figure 8 、 Figure 9 It can be seen that the stage 17 also adopts a low-temperature medium circulation cooling method similar to that of the pressure bar 8 for cooling. Combining Figure 3 It can be further seen that the cold tube 181 at the inlet of the stage should be connected to the microchannel 18 on the side closer to the sample 14 to be measured, so as to preferentially ensure the temperature of the stable sample 14 to be measured. Since there may be differences in the pipe diameters of the microchannel 7 in the pressure bar and the cold tubes for circulation and the microchannel 18 in the stage and the cold tubes for circulation, in order to eliminate the influence of different pipe diameters on the refrigeration effect, two independent refrigeration hosts can be integrated into the refrigeration device 20 to cool the pressure bar 8 and the stage 17 separately, so as to achieve precise control of the temperatures of the diamond indenter 10 and the sample 14 to be measured.

[0050] The refrigeration device 20 can refer to conventional heat exchange equipment such as ice machines in the prior art. Obviously, its heat dissipation end should be arranged far away from the pressure bar 8 and the stage 17. Especially when the experimental device in the present invention is used for experiments in the form of being built into a sealed box, the refrigeration device 20 or the heat dissipation end of the refrigeration device 20 should be arranged outside the sealed box to avoid the heat generated from affecting the low-temperature environment required for the whole experimental device.

[0051] See Figure 1, a heat conduction wire 12 is also provided between the pressure bar 8 and the stage 17. One end of the heat conduction wire 12 is connected to the position close to the diamond indenter 10, and the other end is connected to the position close to the sample 14 to be measured on the stage 17, enabling heat exchange between the pressure bar 8 and the stage 17 through the heat conduction wire 12. As can be seen from the above, due to the difference in the specification sizes between the pressure bar 8 and the stage 17, the specifications of the microchannels inside them are also different. At the same time, it is difficult to make the refrigeration powers of different refrigeration devices 20 exactly the same. This will cause the temperatures between the pressure bar 8 and the stage 17 during the experiment to usually not be exactly equal to the set experimental temperature, resulting in a temperature difference between the diamond indenter 10 and the sample 14 to be measured, which is equivalent to introducing an additional temperature variable during the experiment and further affecting the accuracy of the impact indentation experiment results. Therefore, in the present invention, a heat conduction wire 12 is provided between the pressure bar 8 and the stage 17. The heat conduction wire 12 can be composed of multiple thin wires of materials with good thermal conductivity. It enables contact to be formed between the pressure bar 8 and the stage 17, thereby allowing the heat of the two to be transferred to each other between the heat conduction wires 12, facilitating the balance of the temperature difference between the two, and eliminating to a certain extent the temperature error caused by the different cooling capacities generated by different refrigeration devices 20. In this embodiment, the material of the heat conduction wire 12 is made of copper, which has good ductility and excellent heat conduction effect. In addition, if the heat conduction wire 12 is too long, the heat conduction efficiency will be reduced, and if it is too short, it may affect the result of the impact indentation process due to the stretching effect. Therefore, the heat conduction wire 12 should be selected with an appropriate length according to the experimental needs.

[0052] See Figure 1 , Figure 4 , Figure 5 , a refrigeration balancer 21 is also provided below the pressure bar 8. The refrigeration balancer 21 includes an outer frame 211, a heat conduction plate 212, a limit hanging buckle 213, and a cold storage container 214. The outer frame 211 is a hollow container with at least one set of side openings. At least part of its top surface is the heat conduction plate 212. A limit hanging buckle 213 is provided above the top surface and is closely attached to the heat conduction plate 212. The limit hanging buckle 213 can clamp the heat conduction wire 12 on the top surface of the outer frame 211 to keep it in contact with the heat conduction plate 212. It can be seen that during the experiment, the limit hanging buckle 213 at the top of the refrigeration balancer 21 can clamp the heat conduction wire 12 to keep it in contact with the heat conduction plate 212, preventing the heat conduction wire 12 from detaching from the heat conduction plate 212 and unable to conduct temperature during the impact indentation experiment.

[0053] Inside the outer frame 211, a cold storage container 214 that completely fills its internal space is detachably arranged, and the cold storage container 214 can be arbitrarily disassembled and replaced as needed; at least one side of the cold storage container 214 is a transparent observation window 215, and the observation window 215 is located at the side opening of the outer frame 211. The top of the cold storage container 214 is a cold conduction top plate 216. The inside of the cold storage container 214 is filled with a phase change material 217, so that the phase change material 217 can successively perform heat exchange with the cold conduction wire 12 through the cold conduction top plate 216 and the cold conduction plate 212. The phase change material 217 can fully release or absorb latent heat during the phase change process, so that the temperature of the surrounding environment can remain stable for a long time. After the cold storage container 214 is arranged in the outer frame 211, the phase change material 217 can provide cold (i.e., absorb the heat of both) to the pressure bar 8 and the loading platform 17 through the cold conduction wire 12 respectively, so that the temperatures of the pressure bar 8 and the loading platform 17 are stabilized at the phase change point temperature, that is, the experimental required temperature, to ensure that both the pressure bar 8 and the loading platform 17 can be maintained at the experimental temperature during the impact pressing process, and to ensure the accuracy of the experimental results. Obviously, in order to ensure that the phase change material can play the role of heat absorption and cold supply, it is necessary to make the low-temperature phase change point of the phase change material equal to the experimental temperature. Therefore, before the experiment, it is necessary to fill the phase change material 217 in the cold storage container 214 according to the temperature conditions of the experiment and pre-cool it to the phase change point temperature equal to the experimental temperature. The phase change material 217 is preferably a material with a wide phase change point range such as a phase change polymer; in addition, since the heat transfer process between the phase change material 217 and the cold conduction wire 12 needs to pass through the cold conduction top plate 216 and the cold conduction plate 212 in sequence, the constituent materials of the cold conduction top plate 216 and the cold conduction plate 212 are preferably materials with a higher thermal conductivity than the cold conduction wire 12. In this embodiment, the same copper material as it is used.

[0054] In this embodiment, a camera assembly 22 is provided on one side of the refrigeration balancer 21. The imaging area of the camera assembly 22 includes the entire observation window 215. The camera assembly 22 can adopt a conventional camera device in the prior art, and its usage method is the same as that of the infrared thermal imaging assembly 11, that is, it is electrically connected to an external host or an electronic control module, and directly transmits the collected video data to the external host or the electronic control module. The function of the camera assembly 22 is to observe the state of the phase change material 217 through the observation window 215. When the camera assembly 22 observes that the phase change material 217 is in a two-phase coexistence state, it means that the phase change material 217 is at the phase change point, and the temperature will remain stable. It can stably absorb heat and provide cooling for the pressure bar 8, the stage 17, and the diamond indenter 10 and the sample to be measured 14 respectively provided thereon. At this time, the experimental data collected is accurate data. If the camera assembly 22 observes that the phase change material 217 is in a single phase state outside the phase change point, it means that the phase change material 217 can no longer stably absorb heat and provide cooling. At this time, the experimental data collected is suspicious data, and it needs to be judged whether to retain it according to the specific situation. In addition, when the experimental device is arranged in a closed box, the camera assembly 22 can assist in observing the internal situation.

[0055] See Figure 3 and Figure 6 , a pressure bar thermocouple 9 is arranged on the pressure bar 8 close to the diamond indenter 10, and a stage thermocouple 13 is arranged on the stage 17 close to the sample to be measured 14. The distances between the pressure bar thermocouple 9 and the diamond indenter 10 and between the stage thermocouple 13 and the sample to be measured 14 are both within 0.5 mm. In addition to using the infrared thermal imaging assembly 11 to obtain temperature information, the thermocouples directly arranged on the pressure bar 8 and the stage 17 can more real-time and accurately obtain the temperature change information of the two during the experiment, and the contact distances between the two thermocouples and the diamond indenter 10 and the sample to be measured 14 are both within 0.5 mm, enabling them to obtain the temperature data of the diamond indenter 10 and the sample to be measured 14 without affecting the impact indentation experiment.

[0056] In this embodiment, a cold insulation baffle 6 for blocking the low temperature from being conducted to the force sensor 5 is arranged between the force sensor 5 and the pressure bar 8. The cold insulation baffle 6 is mainly used to accommodate and block the cold quantity, and its material can adopt aluminosilicate ceramic material with low price, easy processing and good cold insulation effect, so as to minimize the low temperature conduction to the force sensor 5 and affect the measurement accuracy of the force sensor 5.

[0057] In addition, the surfaces of the pressure bar inlet cold pipe 71, the pressure bar outlet cold pipe 72, the stage inlet cold pipe 181, and the stage outlet cold pipe 182 in this embodiment are all coated with heat insulation materials, which can reduce the low temperature dissipation and further improve the refrigeration efficiency of the pressure bar 8 and the stage 17.

[0058] The testing method of the above-mentioned micro-nano impact indentation testing device based on cyclic refrigeration is as follows:

[0059] Step S1: Assemble the refrigeration pipeline according to the device, fix the sample to be tested on the stage, install a diamond indenter on the indenter rod, and adjust the stage and the indenter rod so that the position of the diamond indenter corresponds to that of the sample to be tested;

[0060] Step S2: Clamp the heat conduction wire in the limit hanging buckle of the refrigeration balancer, keep it in contact with the heat conduction plate, fill the phase change material with the phase change point equal to the experimental temperature in the cold storage container according to the experimental requirements, and pre-cool the phase change material to a temperature above the phase change point in advance;

[0061] Step S3: Output the protective gas through the protective gas channel, set the infrared thermal imaging component and the camera component to the working state, start the refrigeration device to perform cyclic refrigeration on the indenter and the stage respectively until the experimental temperature is reached, and place the cold storage container filled with the pre-cooled phase change material in the refrigeration balancer, and supply cold from the phase change point in the cold storage container to the indenter and the stage respectively, so that the temperatures of both can be stably maintained at the phase change point temperature, that is, the experimental temperature;

[0062] Step S4: After observing that the indenter and the stage are stable at the experimental temperature, control components such as the driving platform and the piezoelectric stack to perform a low-temperature impact indentation experiment, and collect mechanical, displacement, and temperature data related to the impact indentation experiment. Among them, the displacement data is the displacement data of the diamond indenter in the low-temperature impact indentation experiment. This data can refer to the conventional method for obtaining displacement data in the prior art, and a displacement sensor with a data acquisition range that can cover the entire moving range of the diamond indenter is set on the device or the side to collect the data.

[0063] In summary, the present invention adopts two-stage drive to achieve "electromagnetic-piezoelectric" coupled impact. After the linear motor realizes "long-range approach", the piezoelectric stack completes "transient indentation". The mechanical test data of the material is obtained through a force sensor, the displacement data of the diamond indenter is obtained through a displacement sensor, the temperature data of the diamond indenter and the sample to be tested is obtained through a thermocouple, and the function of applying a load at any point of the sample is realized by using the driving platform and the sliding table, and the lattice-type low-temperature impact indentation performance test of the sample is completed.

[0064] Among them, the low-temperature loading method uses the method of embedding microchannels to cool the sample to be tested and the indenter simultaneously, and uses the heat conduction wire to quickly balance the temperature difference. At the same time, a detachable cold storage container with an internal phase change material in contact with the heat conduction wire is also used to supply cold to the sample and the indenter. Through the phase change endothermic process of the phase change material, the temperatures of the sample and the indenter are stably maintained at the experimentally preset temperature, so that the temperature conditions of the experiment are precisely controlled, the temperature difference between the sample and the indenter is eliminated, and the problem of the influence of temperature drift on the test accuracy is effectively solved.

[0065] In addition, the experimental device can adjust the output power in real time according to the information fed back by the thermocouple and the infrared thermal imaging component. Continuous temperature adjustment can be achieved by adjusting the temperature of the refrigeration medium and replacing the cold storage container. It has a simple structure and a compact layout, does not require an atmosphere refrigeration chamber, and is easy for the tester to integrate multi-physical field in-situ monitoring components, providing a method with relatively high accuracy for revealing the microscopic failure mechanism and its performance evolution law of materials under low-temperature impact conditions.

[0066] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as a limitation to the present invention.

[0067] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the embodiments of the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A micro-nano impact indentation test device based on cyclic refrigeration, characterized in that: It comprises a linear motor (1), a driving platform (2), a piezoelectric stack (4), a pressure rod (8), an infrared thermal imaging component (11), a stage (17), a slide (19), and a refrigeration device (20), wherein: The driving platform (2) is arranged on the linear motor (1) and can move toward the object carrier (17) under the drive of the linear motor (1); a hinge base (3) is also arranged on the driving platform (2); a connected piezoelectric stack (4) and a pressure rod (8) are arranged on the hinge base (3); a diamond pressure head (10) is arranged at the tip of the pressure rod (8), so that the pressure rod (8) and the diamond pressure head (10) can move toward the object carrier (17) under the push of the piezoelectric stack (4); a force sensor (5) is arranged between the pressure rod (8) and the piezoelectric stack (4) for obtaining the driving force applied by the piezoelectric stack (4) to the pressure rod (8); The stage (17) is arranged on the slide (19), and a clamp (15) is arranged on the surface of the stage (17) facing the pressure rod (8). The clamp (15) can stably clamp the sample (14) to be tested, and the diamond indenter (10) can move to contact the sample (14) to be tested, and the stage (17) can move along the slide (19) to a position where the sample (14) to be tested is directly opposite to the tip of the pressure rod (8); The infrared thermal imaging component (11) is arranged on one side of the pressure rod (8), and its infrared thermal imaging range includes the force sensor (5), the pressure rod (8), the sample to be tested (14) and the loading platform (17); The refrigeration device (20) is arranged on one side of the pressure rod (8), and is connected to the pressure rod microchannel (7) buried inside the pressure rod (8) through the pressure rod inlet cold pipe (71) and the pressure rod outlet cold pipe (72) to form a circulation pipeline, so that the refrigeration device (20) can circulate the refrigeration medium inside the pressure rod (8); the refrigeration device (20) is also connected to the stage microchannel (18) buried inside the stage (17) through the stage inlet cold pipe (181) and the stage outlet cold pipe (182) to form a circulation pipeline, so that the refrigeration device (20) can circulate the refrigeration medium inside the stage (17); A cooling wire (12) is also provided between the pressure rod (8) and the stage (17), wherein one end of the cooling wire (12) is connected to a position close to the diamond indenter (10), and the other end of the cooling wire (12) is connected to a position close to the sample to be tested (14) on the stage (17), so that heat exchange can be performed between the pressure rod (8) and the stage (17) through the cooling wire (12); A refrigeration balancer (21) is arranged below the pressure rod (8), wherein the refrigeration balancer (21) comprises an outer frame (211), a cold conduction plate (212), a limit hook (213), and a cold storage container (214); the outer frame (211) is a hollow container with at least one set of side openings, at least a portion of its top surface is the cold conduction plate (212), and a limit hook (213) is arranged above the top surface and is arranged close to the cold conduction plate (212); the limit hook (213) can clamp the cold conduction line (12) on the top surface of the outer frame (211) to maintain contact with the cold conduction plate (212); A cold storage container (214) completely filling the internal space thereof is detachably provided inside the outer frame (211); the cold storage container (214) has at least one transparent observation window (215) on the side, and the observation window (215) is located at the side opening of the outer frame (211); the top of the cold storage container (214) is a cold conduction top plate (216); the cold storage container (214) is filled with a phase change material (217), so that the phase change material (217) can sequentially pass through the cold conduction top plate (216) and the cold conduction plate (212) to perform heat exchange with the cold conduction line (12).

2. The micro-nano impact indentation testing device based on cyclic refrigeration according to claim 1, characterized in that: A camera assembly (22) is provided on one side of the refrigeration balancer (21), and the camera area of ​​the camera assembly (22) includes the entire observation window (215).

3. The micro-nano impact indentation testing device based on cyclic refrigeration according to claim 1, characterized in that: The material of the cooling wire (12), the cooling plate (212) and the cooling top plate (216) is red copper.

4. The micro-nano impact indentation testing device based on cyclic refrigeration according to claim 1, characterized in that: A pressure rod thermocouple (9) is arranged on the pressure rod (8) near the diamond indenter (10), and a stage thermocouple (13) is arranged on the stage (17) near the sample to be tested (14), and the distance between the pressure rod thermocouple (9) and the diamond indenter (10) and the distance between the stage thermocouple (13) and the sample to be tested (14) are both within 0.5 mm.

5. The micro-nano impact indentation testing device based on cyclic refrigeration according to claim 1, characterized in that: A cold-insulating baffle (6) is provided between the force sensor (5) and the pressure rod (8) to prevent low temperature from being conducted to the force sensor (5).

6. The micro-nano impact indentation testing device based on cyclic refrigeration according to claim 1, characterized in that: The surfaces of the pressure rod inlet cold pipe (71), the pressure rod outlet cold pipe (72), the loading platform inlet cold pipe (181), and the loading platform outlet cold pipe (182) are all coated with heat-insulating materials.

7. The micro-nano impact indentation testing device based on cyclic refrigeration according to claim 1, characterized in that: The slide table (19) is also provided with a protective gas channel (16) capable of spraying protective gas toward the hinge base (3).

8. The micro-nano impact indentation testing device based on cyclic refrigeration according to claim 1, characterized in that: The slide table (19) is a sliding member with a single degree of freedom in upper and lower directions.

9. A micro-nano impact indentation test method based on cyclic refrigeration, characterized in that: The test is performed using the device as described in any one of claims 1 to 8, comprising the following steps: Step S1: assembling the refrigeration pipeline according to the device, fixing the sample to be tested on the stage, installing the diamond indenter on the pressure rod, and adjusting the stage and the pressure rod so that the position of the diamond indenter corresponds to the position of the sample to be tested; Step S2: The cooling wire is clamped in the limit hook of the refrigeration balancer to keep it in contact with the cooling plate, and the phase change material corresponding to the experimental temperature is filled in the cold storage container according to the experimental requirements, and the phase change material is pre-cooled at the experimental temperature; Step S3: outputting the protective gas through the protective gas channel, setting the infrared thermal imaging component and the camera component to a working state, starting the refrigeration device to cyclically cool the pressure head and the stage respectively until the experimental temperature is reached, and placing the cold storage container filled with the pre-cold phase change material in the refrigeration balancer; Step S4: After observing that the indenter and the stage are stable at the experimental temperature, control the drive platform and the piezoelectric stack assembly to perform a low-temperature impact indentation experiment, and collect relevant data of the impact indentation experiment.

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