Thermal fatigue test device for metal micro-size sample

Abstract

The invention discloses a metal micro-size sample thermal fatigue test device and belongs to the field of thermal fatigue tests. The device provided by the invention takes power-on and power-off as a cyclic thermal load and can be used for carrying out thermal fatigue test on a plurality of samples at the same time. The thermal fatigue device satisfies (1) rapid temperature cycling, including rapid heating and cooling, so as to improve efficiency; (2) the clamping mode of the sample is reasonable in design, so that no adverse effect is generated on a thermal fatigue test result; (3) no external load is generated on the test piece in the heating and cooling processes, so that data failure in test data is only caused by thermal stress generated in thermal circulation; (4) multiple test pieces are supported to be tested at the same time, the test efficiency is remarkably improved, and more sufficient data support is provided for reliability analysis; (5) the accuracy of temperature measurement is ensured; (6) the equipment has a full-automatic control function, and automatic adjustment can be realized without continuous guarding of testers; the system has an unattended operation function, and can automatically stop and perform early warning under certain conditions.

Description

Technical Field

[0001] The invention relates to a thermal fatigue test, is suitable for simultaneously carrying out thermal fatigue tests on a plurality of metal micro-size specimens, and belongs to the field of thermal fatigue tests. Background Art

[0002] High-tech precision electronic components in fields like aerospace often feature unusually sized metal strips (hereinafter referred to as metal strips). These strips are typically extremely thin and narrow, and are constantly subjected to cyclical thermal loads from power on and off. This exposure results in periodic thermal stresses and makes them susceptible to thermal fatigue failure. To effectively assess the fatigue life of these components, thermal fatigue testing of these strips is necessary to obtain relevant data.

[0003] Existing test equipment is usually designed for large-scale specimens and has the following characteristics: (1) The specimen is heated by ambient heating, such as incubator heating or induction heating, which heats the surrounding environment before the specimen is heated; (2) The cooling method generally uses high-pressure gas or water to cool the environment and then cool the specimen; (3) The specimen is generally in the form of a standard specimen, commonly known as a bone, with large ends and a thin middle. The result is a long thermal fatigue test cycle; the specimen is subjected to external loads such as gas, and when the specimen is small and thin, these external loads have a great impact on its fatigue life; in addition, small, soft and thin metals are generally supplied in strip form, which is not easy to process into a bone shape. Therefore, a suitable thermal fatigue device is needed to perform thermal fatigue tests on small and thin metal specimens. Summary of the Invention

[0004] The purpose of the present invention is to provide a device for thermal fatigue testing of micro-sized metal strips, which uses power on and off as a cyclic heat load and can simultaneously perform thermal fatigue tests on multiple specimens. The thermal fatigue device meets the following requirements: (1) rapid temperature cycling, including rapid heating and cooling, so as to improve efficiency; (2) reasonable design of the specimen clamping method to ensure that there is no adverse effect on the thermal fatigue test results; (3) no external load is generated on the specimen during the heating and cooling process, so that the failure of the test data is only due to the thermal stress generated during the thermal cycle; (4) it supports the simultaneous testing of multiple specimens, significantly improving the test efficiency and providing more sufficient data support for reliability analysis; (5) it ensures the accuracy of temperature measurement; (6) the equipment has a fully automatic control function, which can achieve automatic adjustment without the need for continuous supervision of test personnel; it has an unmanned operation function, and can automatically shut down and issue warnings under certain conditions.

[0005] In particular, the present invention provides a thermal fatigue testing device comprising:

[0006] External frame, used to support other components and lock them in place;

[0007] Mechanical module, the hardware part of the experimental device, is used to meet the necessary hardware requirements of the test and test multiple specimens simultaneously;

[0008] Temperature measurement module, used to monitor temperature changes in real time during the test and collect data;

[0009] The heating module is used to control the actual output voltage, connect the current, and heat the test piece to the expected temperature;

[0010] The cooling module is used to reduce the temperature of the specimen by lowering the temperature of the specimen through the ambient temperature. This process does not generate additional load.

[0011] Automatic control module, used to control various experimental parameters, automatically adjust temperature deviation to control actual specimen temperature, count, automatically shut down and issue warnings;

[0012] Protection module, used to prevent liquid leakage and protect the experimental device.

[0013] In one embodiment of the present invention, the external frame includes a double-layer external frame, a box-type external frame and a two-color infrared thermometer bracket. The double-layer external frame is stacked and placed on the box-type external frame. The box-type external frame contains a mezzanine, and the left and right inner walls of the mezzanine are provided with guide rails. The two-color infrared thermometer bracket supports the movement of the thermometer in different directions so as to measure the temperature at different points. The thermometer is connected to the clamping block using studs. The lower side of the clamping block has a strip-shaped slider, which is connected by a slider guide rail, and the position of the thermometer is locked by studs. The guide rail is connected to the bracket fixing plate guide rail, and the position is locked by an adjustment switch. The fixed plate guide rail is connected to the outer wall of the environmental chamber door. The environmental chamber door is provided with an observation frame, which is connected to the lower outer wall of the double-layer external frame by a hinge. The gap between the door and the double-sided external frame is blocked by a sealing ring, and the sealing ring is connected to the environmental chamber door by sealant.

[0014] In one embodiment of the present invention, the mechanical module includes a fixture assembly and a fixture fixing plate. The fixture assembly is connected to the fixture fixing plate via screws, and the spacing between the individual fixtures is adjusted using screws. Each fixture in the fixture assembly is tightened and loosened using screws to secure and remove the specimen. This fixture assembly meets thermal and electrical conductivity requirements while facilitating processing without affecting the specimen's shape, allowing thermal fatigue testing to be performed directly on the actual engineering shape. The fixture fixing plate is connected to the rear wall of the environmental chamber via screws.

[0015] In one embodiment of the present invention, the temperature measurement module includes a high-temperature temperature measurement device and a low-temperature temperature measurement device. The high-temperature temperature measurement device is a two-color infrared thermometer. The low-temperature temperature measurement device is a resistance thermometer, which operates as part of the refrigeration chassis. The low-temperature temperature of the environmental chamber is measured by the resistance thermometer, and the data is directly received by the refrigeration chassis. The resistance thermometer is placed in the center of the fixture plate.

[0016] In one embodiment of the present invention, the temperature-raising module includes a PC, a power controller, a voltage heating device, and an environmental chamber. The PC outputs a signal indicating the desired temperature and corresponding power to the power controller via a signal transmission line. The power controller outputs a corresponding voltage signal to the heating device via a signal transmission line. The voltage heating device is connected to the fixtures at both ends of the fixture assembly within the environmental chamber via a current path, which is connected to the fixtures at both ends via screws.

[0017] In one embodiment of the present invention, the cooling module includes a refrigeration chassis, a heat sink, and an environmental chamber. The refrigeration chassis is connected to the heat sink via a liquid circulation pipe, which delivers a cooling medium, such as antifreeze. The heat sinks are symmetrically positioned on either side of a fixture fixing plate and secured in place by screws. The arrangement of the cooling medium delivery pipes within the heat sinks achieves uniform cooling.

[0018] In one embodiment of the present invention, the automatic control module is controlled by a PC to control various parameters in the experiment to automatically perform experiments and adjust deviations, collect and record data, and issue early warnings.

[0019] In one embodiment of the present invention, the protection module includes a metal tray, which is respectively placed below the fixture group and the heat sink in the environmental chamber and above the power controller in the box-type external frame interlayer. The metal tray above the power controller in the box-type external frame interlayer is controlled and fixed in position by a guide rail.

[0020] The present invention directly energizes the specimen, utilizing its resistance to heat it without requiring ambient heating. This effectively addresses the issue of heating tiny specimens while enabling rapid temperature increases. Combined with a low-temperature environmental chamber, power can be turned off at the end of temperature increase, enabling rapid cooling due to the small size and low heat content of the specimen. Furthermore, the environmental chamber utilizes a heat sink to circulate coolant for accelerated cooling, without placing additional load on the specimen. This allows for thermal fatigue performance testing of tiny metals, and combined with precise temperature measurement, provides more reliable test results.

[0021] The present invention allows multiple test pieces to be subjected to thermal fatigue tests simultaneously, thus greatly shortening the test cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a micro-sized metal thermal fatigue testing device according to one embodiment of the present invention. DETAILED DESCRIPTION

[0023] Figure 1A micro-sized metal thermal fatigue testing device according to an embodiment of the present invention includes an external frame 10 , a mechanical module 20 , a temperature measurement module 30 , a temperature increasing module 40 , a temperature decreasing module 50 , a protection module 60 and an automatic control module 70 .

[0024] The external frame 10 provides a base for each device. The lower space of the double-layer external frame 11 houses the environmental chamber body 111. An environmental chamber door 112 is mounted outside the environmental chamber body 111, with a sealing ring 113 between door 112 and chamber 111. A dual-color infrared thermometer bracket 13 is mounted outside door 111. The double-layer external frame 11 is stacked atop the box-shaped external frame 12, which has an inner interlayer 121. The external frame can utilize existing components, ensuring a reasonable layout and no interference between sub-devices.

[0025] To ensure accurate temperature measurement, the dual-color infrared thermometer bracket 13 allows the dual-color infrared thermometer 31 to move in the X, Y, and Z directions. The bracket is secured to the X-axis slide with stud bolts, which also lock the X and Y positions of the dual-color infrared thermometer 31 on the guide rail. To determine the X and Y positions simultaneously, the Z position of the dual-color infrared thermometer 31 can be adjusted and locked using the adjustment switch on the Z guide rail.

[0026] The bracket of the dual-color infrared thermometer can be other types of brackets, or a tripod support independent of the device, and can be replaced without affecting the test and weakening the temperature measurement accuracy.

[0027] The mechanical module 20 is used to assume the function of a test bench. The fixture group 21 has multiple groups of fixtures, and the fixtures are placed vertically in two rows on the fixture fixing plate 22. The fixture fixing plate 22 is fixed on the back wall of the environmental chamber body 111. A through hole is opened in the center of the fixture fixing plate 22. The fixtures 211 to 226 all include two groups of chucks, each group of chucks has two clips, which can be tightened by screws, and a clamping section is reserved. The two chucks are then used to fit and tighten the specimen. The length of the test section can be adjusted by the chuck clamp control. The fixture group 21 can be self-developed according to the size of the test specimen. The fixture material is conductive and the resistance is less than the resistance of the specimen. The fixture group can directly clamp and fix extremely thin strip-shaped special-shaped specimens (such as spiral specimens, etc.) without affecting the shape and size of the specimen, so that the specimen can be tested in the actual shape of the project and the working conditions can be restored to the greatest extent. The fixed plate can adopt any plate structure that meets the requirements.

[0028] When in use, adjust the position of the fixture group 21 and then clamp the test piece. Manually adjust the various devices and test parameters before conducting the test. After adjusting the fixture, install the test piece in sequence.

[0029] The temperature measurement module 30 is used to measure temperature changes during the test. A high-temperature temperature measurement device, a two-color infrared thermometer 31, is used to measure the temperature of the specimen. A low-temperature temperature measurement device, a resistance thermometer 32, is used to measure temperature changes within the environmental chamber. The temperature will be directly displayed by the refrigeration chassis 51. The two-color infrared thermometer 31 is used to measure high-temperature changes in small specimens during the test. Due to the size of the specimen, the thermometer's spot size and temperature measurement accuracy must be strictly controlled. When selecting an existing infrared two-color thermometer, the thermometer's spot size diameter must be within the specimen width, the temperature measurement accuracy must be as small as possible, and the response time must be reasonable. The resistance thermometer 32 can use any existing device. The temperature probe must be placed in the center through-hole of the fixture fixing plate 22. The assembly relationship must be determined during selection. The specific parameters of the infrared two-color thermometer and the resistance thermometer can be selected based on the test requirements.

[0030] The heating module 40 is used to heat the specimen to the expected temperature and realizes the separation of control and output. The power controller 41 is used for control and transmits signals to the voltage device 41. It can control the temperature to rise to a certain temperature range within a certain time limit. The voltage heating device 42 receives the signal to confirm the step voltage size and output duration to be output and actually outputs it to heat the specimen. The power controller 41 can be an existing control device or a self-developed control device, as long as the control accuracy is met. The voltage heating device 42 can be an existing control device or a self-developed heating device, as long as the output accuracy is met.

[0031] The cooling module 50 is used to control the ambient temperature to a low temperature. After the heating phase, the test specimen is rapidly cooled through heat transfer. This module is not controlled by the automatic control module and is always on as an independent module to control the temperature of the environmental chamber. The refrigerator 51 cools the environment by delivering coolant to the heat sink 52 and circulates the medium to achieve the cooling effect. The cooling medium is antifreeze. The refrigerator can be selected from existing equipment that meets the cooling effect. The cooling medium can be any liquid with antifreeze properties.

[0032] The automatic control module 60 is used to automatically adjust the temperature deviation caused by the test. Temperature changes will cause changes in the properties of the test piece itself. If the heating is always carried out with the same output, it is inevitable that abnormal phenomena such as excessive temperature changes will occur. The automatic control module 60 can continuously detect high temperatures and make adjustments during the test. Temperature overshoot may also occur during the test. The automatic control module 60 can detect and terminate the test in time. In addition to the above functions, the automatic control module 60 can collect temperature cycle data, cycle number collection, temperature warning, automatic shutdown when the cycle period reaches the standard, and control the above components to load operating parameters according to predetermined test conditions. The automatic control module 60 uses PC 61 as the control terminal to establish communication and control each device of the temperature measurement module 30 and the heating module 40 respectively, and requires independent writing of control programs.

[0033] The protection module 70 is used to receive the liquid generated by the leakage of antifreeze and the liquefaction of the cold air by absorbing heat, protecting the equipment from being soaked by the liquid and causing short circuits. The small leakage tray 71 is used to receive the leaked liquid in the environmental chamber, and the large tray 72 is used to protect the voltage heating device. Any existing receiving container can be used.

[0034] When in use, adjust the fixture position according to the above process, install the test piece, and after installing the test piece, start the control software written by PC61 to preset the parameters required for the test and simulate the engineering environment required for the test. After manually adjusting the temperature of the test piece to the expected temperature, determine the output voltage parameters obtained by manual adjustment, apply them to the test parameter setting, and start the test.

[0035] Furthermore, after a specimen breaks, the machine is stopped to clamp the specimen or replace it with a conductive metal sheet, and the temperature of the specimen is measured again.

[0036] In this embodiment, an infrared two-color thermometer is used to precisely measure the temperature of tiny metal strip specimens. Directly heating the specimen with an electric current, achieving resistive heating, allows for rapid, precise, and uniform temperature increases. In conjunction with the cooling module, rapid cooling can be achieved without the influence of additional loads. The cycle frequency can be determined independently, as long as the cycle speed meets the desired requirements. Thanks to the involvement of the automatic control module 60, the temperature can be continuously adjusted during the test, shortening the test cycle while increasing the accuracy of the test data.

[0037] Those skilled in the art will recognize that although a number of exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications consistent with the principles of the present invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

1. A thermal fatigue test device for metal micro-size specimens, characterized in that include: External frame, used to support other parts and fix the position; Mechanical module, the hardware part of the experimental device, is used to meet the necessary hardware requirements of the test and test multiple specimens simultaneously; Temperature measurement module, used to monitor the temperature changes of the test piece in real time during the test and collect data; The heating module is used to control the actual output voltage, connect the current, and heat the test piece to the expected temperature; The cooling module is used to reduce the temperature of the specimen by keeping the environment at a low temperature. This process does not generate any additional load. Automatic control module, used to control various experimental parameters, automatically adjust temperature deviation to control actual specimen temperature, count, automatically shut down and issue warnings; Protection module, used to prevent liquid leakage and protect the experimental device.

2. The thermal fatigue testing device for metal micro-size specimens according to claim 1, characterized in that: The external frame includes a double-layer external frame, a box-type external frame and a two-color infrared thermometer bracket; the lower layer of the double-layer external frame is a closed environmental box with an observation window, the double-layer external frame is stacked on the box-type external frame, and the box-type external frame is fixed with an extendable and retractable desktop on the right side, and the extendable and retractable desktop can be self-lockingly fixed. The two-color infrared thermometer bracket is connected to the front of the environmental box through a mounting column, and the movement of the two-color infrared thermometer is achieved through a guide rail, and the position of the two-color infrared thermometer is locked through a stud.

3. The thermal fatigue testing device for metal micro-size specimens according to claim 1, characterized in that: The mechanical module includes a fixture group and a fixture fixing plate. The fixture fixing plate is connected to the inner wall of the environmental chamber by bolts. The fixture group has multiple fixtures, which are fixed to the fixture fixing plate by bolts. The fixture is a hollow rectangle that serves as a slide groove. The fixture is fixed to the sliding position of the slide groove by bolts and the fixture spacing is fixed. The fixture is composed of two clips and connected by screws. After the screws are tightened, the two clips are clamped. The fixtures fix a test piece in groups of two.

4. The thermal fatigue testing device for metal micro-size specimens according to claim 1, characterized in that: The temperature measurement module includes a two-color infrared thermometer and a resistance thermometer. The temperature measurement position of the two-color infrared thermometer is framed outside the observation window. The two-color infrared thermometer establishes communication with the PC through a signal path to complete data acquisition. The low temperature of the environmental chamber is measured by the resistance thermometer and the data is directly received by the refrigeration chassis. The resistance thermometer is placed in the center of the fixture fixed plate.

5. The thermal fatigue testing device for metal micro-size specimens according to claim 1, characterized in that: The temperature rising module includes PC control software, a power controller, a voltage heating device and an environmental chamber. The PC is placed on a box-type external frame, the power controller is placed in the upper space of the double-layer external frame, and the voltage heating device is placed in the inner layer of the box-type external frame. The PC and the power controller establish communication through signals, and the power controller and the voltage heating device establish communication through current. The voltage heating device is connected to the two ends of the fixture in the environmental chamber by screws through the current path to directly conduct current to heat the series test pieces and achieve temperature rising. At the same time, the step voltage is controlled by DAC to achieve precise control of temperature rising.

6. The thermal fatigue testing device for metal micro-size specimens according to claim 1, characterized in that: The cooling module includes a refrigeration chassis, a heat sink and an environmental box. The refrigeration chassis is placed in a box-type external frame. The refrigeration chassis is connected to the heat sink through a circulation pipe to circulate the cooled antifreeze liquid; the heat sink is symmetrically placed on both sides of the fixture fixing plate to achieve the function of cooling the environmental box.

7. The thermal fatigue testing device for metal micro-size specimens according to claim 1, characterized in that: The automatic control module is controlled by a PC, and controls various parameters in the experiment to automatically perform experiments and adjust deviations, collect and record data, and issue early warnings.

8. The thermal fatigue testing device for metal micro-size specimens according to claim 1, characterized in that: The protection module includes two metal trays, which are respectively placed below the fixture group in the environmental box and above the power controller in the interlayer of the box-type external frame. The two metal trays are both positioned and fixed by guide rails.

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