Gleeble thermal simulation experiment clamp with controllable temperature gradient and experiment method

Abstract

The invention discloses a Gleeble thermal simulation experiment clamp with a controllable temperature gradient and an experiment method, and belongs to the technical field of thermal simulation experiments. The device comprises an upper clamping block, a lower clamping block and a coaxial sleeve cooler, the upper clamping block and the lower clamping block are pinned through a positioning pin and clamp a sample, a cooling flow channel is formed in the upper clamping block, the coaxial sleeve cooler comprises a mounting block, a liquid inlet pipe, a liquid outlet pipe and a connecting part, the mounting block is mounted on the side wall of the upper clamping block, the liquid inlet pipe and the liquid outlet pipe are arranged at the bottom of the mounting block, and the connecting part is connected with the liquid inlet pipe. A connecting part is arranged on the mounting block, a liquid outlet cavity is formed in the mounting block, the liquid outlet pipe is communicated with the liquid outlet cavity, the liquid inlet pipe extends into the cooling flow channel of the upper clamping block, the liquid outlet cavity is communicated with the cooling flow channel of the upper clamping block through a liquid outlet, and the connecting part extends into a groove formed in the side wall of the upper clamping block. The upper clamping block is cooled through the cooling medium, and low temperature is conducted to the sample through the upper clamping block, so that the sample is subjected to a thermal simulation experiment in a temperature gradient environment, and the reliability of an experiment result is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal simulation experiments, and relates to a Gleeble thermal simulation experiment fixture with controllable temperature gradient and an experiment method. Background Art

[0002] Thermal barrier coatings (TBCs), as an advanced surface protection material, have been widely used in aerospace, energy and many related fields. TBCs are usually coated on the surface of turbine blades to build a thermal insulation barrier to effectively block the direct thermal effect of high-temperature gas flow on the blade substrate. In addition, thermal barrier coatings not only extend the service life of the blades by reducing the surface temperature of the blades, but also significantly improve the overall performance of the engine.

[0003] Due to their complex geometry and harsh service conditions, high-temperature components such as turbine blades are subjected to changing loads. These changing cyclic loads can easily cause fatigue damage to the coating. Under this cyclic alternating stress, the coating is prone to cracking and peeling without warning, which eventually leads to component failure. In order to gain a deeper understanding of the performance of thermal barrier coatings in a variety of working environments, it is necessary to conduct thermal simulation experiments on thermal barrier coatings. With the help of the results of thermal simulation experiments, the actual working conditions of high-temperature components such as turbine blades coated with thermal barrier coatings can be predicted to minimize coating damage without warning, which ultimately leads to component failure.

[0004] Temperature is one of the factors that have an important impact on thermal barrier coatings and is an indispensable condition for predicting the actual working conditions of high-temperature components. Therefore, it is of great significance to simulate the effect of temperature on thermal barrier coatings through thermal simulation experiments. Thermal simulation experiments are usually carried out using a Gleeble thermal simulator.

[0005] During the thermal simulation experiment, the smaller the difference between the experimental conditions and the actual working environment, the higher the reliability of the experimental results, and the more accurate the prediction of the actual working conditions of the subsequent high-temperature components through the experimental results. In the actual working environment of the high-temperature components, the temperature conditions are more complicated and it is easier to produce a temperature gradient environment. Therefore, it is more likely that the high-temperature components will work in a temperature gradient environment.

[0006] Therefore, it is necessary to provide a Gleeble thermal simulation experiment fixture and experimental method with controllable temperature gradient, so that the experimental object can be simulated under temperature gradient conditions, thereby reducing the difference between the experimental conditions and the actual working conditions and improving the reliability of the experimental results. Summary of the invention

[0007] In order to overcome the problems in the background technology, the present invention cools the upper clamp by setting a cooling channel in the upper clamp and conveying a cooling medium into the cooling channel through a coaxial sleeve cooler. At the same time, the cooling medium flow rate is controlled by means of a Gleeble thermal simulator control program to control the cooling effect of the cooling medium on the fixture, and the heat after cooling is conducted to the sample through the fixture to form a temperature gradient on the sample, so that the sample can undergo a Gleeble thermal simulation experiment under temperature gradient conditions, thereby improving the degree of fit between the experimental conditions and the actual situation, thereby improving the reliability of the experimental results.

[0008] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0009] On the one hand, the present invention proposes a Gleeble thermal simulation experiment fixture with controllable temperature gradient, the fixture comprising an upper clamping block 1, a lower clamping block 2, and a coaxial sleeve cooler 4, the upper clamping block 1 and the lower clamping block 2 are connected by a locating pin 5, and a clamping position is provided between the upper clamping block 1 and the lower clamping block 2, a cooling channel is arranged inside the upper clamping block 1, the coaxial sleeve cooler 4 comprises a mounting block, a liquid inlet pipe 7, a liquid outlet pipe 8, and a connecting portion 11, the mounting block is mounted on the side wall of the upper clamping block 1 by bolts, a liquid inlet pipe 7 and a liquid outlet pipe 8 are arranged at the bottom of the mounting block, and a connecting portion 11 is also arranged on the mounting block, a liquid outlet cavity 9 is provided inside the mounting block, the liquid outlet pipe 8 is connected with the liquid outlet cavity 9, the liquid inlet pipe 7 is inserted into the cooling channel of the upper clamping block 1, the liquid outlet cavity 9 is connected with the cooling channel of the upper clamping block 1 through a liquid outlet 10, and the connecting portion 11 extends into a groove provided on the side wall of the upper clamping block 1.

[0010] Preferably, the liquid inlet pipe 7 is connected to the cooling medium source through the original three-way valve of the Gleeble thermal simulator, the cooling medium is driven to circulate by the high-pressure gas source of the Gleeble thermal simulator, and the liquid outlet pipe 8 extends outside the working cavity of the Gleeble thermal simulator.

[0011] Preferably, the connection portion 11 and the groove connection portion of the upper clamping block 1 are sealed using a sealing ring 6.

[0012] Preferably, the upper clamping block 1 is made of heat-conducting material.

[0013] Preferably, the upper clamping block 1 and the lower clamping block 2 are both right-angled trapezoidal structures.

[0014] Another aspect of the present invention provides an experimental method for performing a thermal simulation experiment using the above-mentioned fixture and the Gleeble thermal simulator, the experimental method comprising the following steps:

[0015] (1) Processing the experimental object into a standard specimen;

[0016] (2) welding four pairs of thermocouple wires for measuring temperature in the middle of the standard sample obtained in step (1), wherein the welding positions of the four pairs of thermocouple wires are arranged from the center point of the standard sample to one end of the standard sample;

[0017] (3) Assemble the upper clamp block 1 and the lower clamp block 2, and firmly clamp the standard sample. Meanwhile, install the coaxial sleeve cooler 4 on the upper clamp block 1, connect the liquid inlet pipe 7 to the three-way valve of the Gleeble thermal simulator, and connect to the cooling medium source;

[0018] (4) Install the fixture into the Gleeble thermal simulator;

[0019] (5) setting experimental parameters through the Gleeble thermal simulator control program, wherein the experimental parameters include experimental heating rate, target temperature, fixture cooling speed, and fixture cooling temperature;

[0020] (6) Start the Gleeble thermal simulator to conduct thermal simulation experiments.

[0021] Beneficial effects of the present invention:

[0022] 1. The present invention introduces a cooling medium into the upper clamp block, and reduces the sample temperature through the heat conduction effect of the upper clamp block, thereby creating a temperature gradient condition on the sample, making the sample experimental conditions closer to the actual situation and improving the reliability of the experimental results.

[0023] 2. The present invention makes full use of the existing components of the Gleeble thermal simulator to provide support for fixture cooling, and better combines fixture cooling with the Gleeble thermal simulator, so that the overall structure of fixture cooling is simplified and experimental operation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the three-dimensional structure of the clamp of the present invention for clamping a sample;

[0025] Figure 2 It is a perspective schematic diagram of the upper clamping block structure of the present invention;

[0026] Figure 3 It is a perspective schematic diagram of the lower clamping block structure of the present invention;

[0027] Figure 4 It is a perspective structural schematic diagram of the coaxial cooler of the present invention;

[0028] Figure 5 This is a schematic diagram of the cooling medium flow after the coaxial cooler of the present invention is assembled with the upper clamping block.

[0029] Figure 6 is the temperature gradient of the sample under different cooling medium conditions during the thermal simulation experiment of the present invention;

[0030] Figure 7 is a thermal simulation cycle curve of the thermal barrier coating after multiple thermal cycles in Example 1 of the present invention;

[0031] Figure 8 This is the microstructure of the thermal barrier coating of Example 1 of the present invention after thermal cycling for 80 hours;

[0032] Fig. 9 is a thermal simulation cycle curve of the thermal barrier coating of Example 2 of the present invention after multiple thermal cycles;

[0033] Fig.10 This is the microstructure of the thermal barrier coating of Example 2 of the present invention after thermal cycling for 80 hours.

[0034] In the figure, 1-upper clamp, 2-lower clamp, 3-sample, 4-coaxial cooler, 5-locating pin, 6-sealing ring, 7-liquid inlet pipe, 8-liquid outlet pipe, 9-liquid outlet cavity, 10-liquid outlet, 11-connecting part. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with specific embodiments.

[0036] like Figure 1-4 As shown, an upper clamping block 1, a lower clamping block 2, and a coaxial sleeve cooler 4, the upper clamping block 1 and the lower clamping block 2 are connected by a positioning pin 5, and a clamping position is provided between the upper clamping block 1 and the lower clamping block 2, a cooling channel is arranged inside the upper clamping block 1, and the coaxial sleeve cooler 4 comprises a mounting block, a liquid inlet pipe 7, a liquid outlet pipe 8, and a connecting portion 11, the mounting block is mounted on the side wall of the upper clamping block 1 by bolts, a liquid inlet pipe 7 and a liquid outlet pipe 8 are arranged at the bottom of the mounting block, and a connecting portion 11 is also arranged on the mounting block, a liquid outlet cavity 9 is opened inside the mounting block, the liquid outlet pipe 8 is communicated with the liquid outlet cavity 9, the liquid inlet pipe 7 is inserted into the cooling channel of the upper clamping block 1, the liquid outlet cavity 9 is communicated with the cooling channel of the upper clamping block 1 through a liquid outlet 10, and the connecting portion 11 extends into a groove opened on the side wall of the upper clamping block 1.

[0037] When the Gleeble thermal simulation experiment is conducted, the cooling medium is transported to the cooling channel inside the upper clamp 1 through the liquid inlet pipe 7, so that the temperature of the upper clamp 1 drops, and then the upper clamp 1 conducts the low temperature to the sample 3. Since the standard structure of the sample 3 is a dumbbell shape, the upper clamp 1 and the lower clamp 2 clamp the two ends of the sample 3, and the upper clamp 1 lowers the temperature of the ends of the sample 3 by conducting the low temperature. The closer to the middle part of the sample 3, the higher the temperature due to the heating effect of the Gleeble thermal simulator. Therefore, a temperature gradient is formed on the sample 3, so that the temperature gradient condition is maintained during the entire thermal simulation experiment, thereby improving the reliability of the experimental results.

[0038] The liquid inlet pipe 7 is connected to the cooling medium source through the original three-way valve of the Gleeble thermal simulator. The cooling medium is driven to flow by the high-pressure gas source of the Gleeble thermal simulator. The liquid outlet pipe 8 extends to the outside of the working cavity of the Gleeble thermal simulator.

[0039] Make full use of the original parts of the Gleeble thermal simulator and use them to achieve fixture cooling, minimizing the number of additional parts required to achieve fixture cooling, which is conducive to reducing costs and reducing the complexity of the fixture cooling structure and the complexity of the fixture cooling operation.

[0040] The connection part 11 and the groove connection part of the upper clamping block 1 are sealed by a sealing ring 6. The cooling effect of the cooling medium on the upper clamping block 1 after entering the upper clamping block 1 is enhanced, and the influence of external conditions on the action of the cooling medium is reduced.

[0041] The upper clamping block 1 is made of heat-conducting material.

[0042] The upper clamping block 1 and the lower clamping block 2 are both of right-angled trapezoidal structure.

[0043] When the clamp is in use, the inclined surface of the upper clamp block 1 faces upwards, and the inclined surface of the lower clamp block 2 faces downwards for clamping, and at the same time cooperates with the Pocketjaw of the Gleeble thermal simulator.

[0044] Example 1

[0045] In this embodiment, the Gleeble thermal simulation experiment is performed using the above-mentioned fixture to clamp the sample according to the following method:

[0046] (1) Processing the experimental object into a standard sample. The experimental object of this embodiment is a 4099 nickel-based alloy sprayed with a thermal barrier coating, with a substrate thickness of 2 mm and a coating thickness of about 0.1 mm. The 4099 nickel-based alloy is processed into a dumbbell-shaped sheet (such as Figure 1 , 5 shown).

[0047] (2) Figure 1 , 6 As shown, four pairs of thermocouple wires are welded in the middle of the standard sample. In this embodiment, the thermocouple wires are recorded as TC1, TC2, TC3, and TC4 in order from the middle to one end. The temperatures at different positions on the standard sample are measured according to TC1, TC2, TC3, and TC4, and the temperatures measured by the thermocouple wires are recorded in the system. Among them, the temperature measured by TC1 is also used as the standard for program control of experimental temperature conditions. The program determines whether the experimental temperature needs to be adjusted and the temperature range according to the temperature measured by TC1.

[0048] (3) Assemble the upper clamp 1 and the lower clamp 2, and make sure that the upper clamp 1 and the lower clamp 2 firmly clamp the standard specimen (such as Figure 1 As shown in the figure, through holes can be opened at both ends of the standard sample. During the assembly of the upper and lower clamps, the positioning pins are passed through the through holes at both ends of the standard sample, and then the upper and lower clamps are pinned to further strengthen the stability of the clamp holding the standard sample. The coaxial cooler 4 is installed on the upper clamp 1 by bolts, and the entire cooling pipeline is connected.

[0049] (4) Install the fixture into the Gleeble thermal simulator.

[0050] (5) Through the Quicksim software, set the experimental parameters such as heating rate, target temperature, cooling speed, etc., and realize automatic control of the Gleeble thermal simulator through the software. The Gleeble thermal simulator comes with two solenoid valves, Quench3 and Quench4. Quench3 and Quench4 are responsible for controlling the on and off of the high-pressure gas source. Since the flow of the cooling medium can be driven by the high-pressure gas source of Gleeble, the on and off of the high-pressure gas source and the pressure of the high-pressure gas source can be controlled by the above two solenoid valves. The flow of the cooling medium can be controlled to achieve different cooling effects of the fixture. In the process of setting the experimental parameters, the type of cooling medium must be considered. There are differences in cooling effects between different types of cooling media (such as Figure 6 In this embodiment, the set heating rate is 5°C / s, the target temperature is 1100°C, and the holding time is 15 minutes. After that, the standard sample is cooled. During the whole experimental process, the nickel-based alloy is continuously cycled in the process of heating, cooling, heating, and cooling.

[0051] (6) Start the Gleeble thermal simulator to conduct thermal simulation experiments.

[0052] During the experiment of this embodiment, the thermal simulation cycle curve is as follows Figure 7 As shown in Figure 8, the microstructure of the thermal barrier coating after 80h thermal cycle is shown in Figure 8.

[0053] pass Figure 7 It can be seen that during the experiment, the standard sample maintained a relatively stable temperature gradient state, in which the temperature decreased from the middle part to the end of the standard sample.

[0054] pass Figure 8 It can be seen that the coating Figure 7 Changes in the microstructure after 80h of thermal cycling under temperature gradient conditions.

[0055] Example 2

[0056] This embodiment and Embodiment 1 use the same sample, fixture and Gleeble thermal simulator to carry out thermal simulation experiments, the difference being that in this embodiment, a tension is applied to the standard sample, and the tension value is 60 kgf.

[0057] During the experiment of this embodiment, the thermal simulation cycle curve is as follows Fig. 9 As shown in Figure 2, the microstructure of the thermal barrier coating after 80h thermal cycling is as follows: Fig.10 shown.

[0058] pass Fig. 9 It can be seen that during the experiment, the standard sample maintained a relatively stable temperature gradient state, in which the temperature decreased from the middle part to the end of the standard sample.

[0059] pass Fig.10 It can be seen that under the conditions of a specific temperature gradient and a 60Kgf tensile force, the coating's microstructure changes after 80 hours of thermal cycling. This experiment simulates the actual operating conditions of the coating under a thermal-mechanical coupling environment and obtains a structure evolution law that is close to reality.

[0060] In summary, the fixture of the present invention can effectively create a relatively stable temperature gradient environment for the sample during use, so that the experimental environment conditions of the sample during the thermal simulation experiment are closer to the actual working environment conditions, thereby improving the reliability of the experimental results. At the same time, the present invention makes full use of Gleeble original accessories to provide assistance for the fixture cooling process, which is beneficial to reduce the complexity of the fixture cooling structure and simplify the operation process.

[0061] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A Gleeble thermal simulation test fixture with controllable temperature gradient, characterized in that: The clamp comprises an upper clamp block (1), a lower clamp block (2), and a coaxial sleeve cooler (4); the upper clamp block (1) and the lower clamp block (2) are connected via a positioning pin (5); a clamping position is provided between the upper clamp block (1) and the lower clamp block (2); a cooling channel is provided inside the upper clamp block (1); the coaxial sleeve cooler (4) comprises a mounting block, a liquid inlet pipe (7), a liquid outlet pipe (8), and a connecting portion (11); the mounting block is mounted on the side of the upper clamp block (1) via bolts. A liquid inlet pipe (7) and a liquid outlet pipe (8) are arranged on the wall at the bottom of the mounting block, and a connecting portion (11) is also arranged on the mounting block. A liquid outlet cavity (9) is arranged inside the mounting block, and the liquid outlet pipe (8) is communicated with the liquid outlet cavity (9). The liquid inlet pipe (7) is inserted into the cooling channel of the upper clamping block (1), and the liquid outlet cavity (9) is communicated with the cooling channel of the upper clamping block (1) through the liquid outlet port (10). The connecting portion (11) extends into a groove arranged on the side wall of the upper clamping block (1).

2. The Gleeble thermal simulation test fixture with controllable temperature gradient according to claim 1, characterized in that: The liquid inlet pipe (7) is connected to the cooling medium source through the original three-way valve of the Gleeble thermal simulator, and the cooling medium is driven to circulate by the high-pressure gas source of the Gleeble thermal simulator. The liquid outlet pipe (8) extends to the outside of the working cavity of the Gleeble thermal simulator.

3. The Gleeble thermal simulation test fixture with controllable temperature gradient according to claim 1, characterized in that: The connection portion (11) and the groove connection portion of the upper clamping block (1) are sealed using a sealing ring (6).

4. The Gleeble thermal simulation test fixture with controllable temperature gradient according to claim 1, characterized in that: The upper clamping block (1) is made of heat-conducting material.

5. The Gleeble thermal simulation test fixture with controllable temperature gradient according to claim 1, characterized in that: The upper clamping block (1) and the lower clamping block (2) are both of right-angled trapezoidal structure.

6. A thermal simulation experimental method, characterized in that: The experiment is conducted using a Gleeble thermal simulator, and the sample is clamped using the fixture described in any one of claims 1 to 5. The experimental method comprises the following steps: (1) Processing the experimental object into a standard specimen; (2) welding four pairs of thermocouple wires for measuring temperature in the middle of the standard sample obtained in step (1), wherein the welding positions of the four pairs of thermocouple wires are arranged from the center point of the standard sample to one end of the standard sample; (3) Assemble the upper clamp (1) and the lower clamp (2) and firmly clamp the standard sample. Meanwhile, install the coaxial sleeve cooler (4) on the upper clamp (1), connect the liquid inlet pipe (7) to the three-way valve of the Gleeble thermal simulator, and connect to the cooling medium source; (4) Install the fixture into the Gleeble thermal simulator; (5) setting experimental parameters through the Gleeble thermal simulator control program, wherein the experimental parameters include experimental heating rate, target temperature, fixture cooling speed, and fixture cooling temperature; (6) Start the Gleeble thermal simulator to conduct thermal simulation experiments.

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