Experimental device for tensile experiment in supercritical carbon dioxide environment

Abstract

The embodiment of the invention provides an experimental device for a tensile experiment in a supercritical carbon dioxide environment. The experimental device comprises a high-pressure kettle, a first tensile piece, a second tensile piece, a first clamp assembly, a second clamp assembly and a flaky sample test piece, wherein the first tensile piece and the second tensile piece are connected to the top end and the bottom end of the high-pressure kettle respectively; the first clamp assembly is connected to the first stretching part, the second clamp assembly is connected to the second stretching part, and the first clamp assembly and the second clamp assembly cooperate to clamp and fix a sheet sample test piece; the first clamp assembly is at least provided with a pair of first positioning holes located at the diagonal positions, the second clamp assembly is provided with second positioning holes corresponding to the first positioning holes, and ceramic alloy bars are inserted into the first positioning holes and the corresponding second positioning holes and used for limiting angle deviation between the first clamp assembly and the second clamp assembly. The autoclave is used for providing a high-temperature and high-pressure environment of supercritical carbon dioxide. The clamp angle stability in the experiment process can be effectively guaranteed, and the test accuracy is improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure belong to the technical field of tensile test, and particularly relate to an experimental device for tensile test under supercritical carbon dioxide environment. BACKGROUND

[0002] In the test of high-temperature mechanical properties of materials, high-temperature tensile test is an important means to obtain the strength, plasticity and other performance data of materials in high-temperature environment. With the development of new energy technology, the demand for material performance test in supercritical carbon dioxide environment is increasing, such as the performance evaluation of materials in supercritical carbon dioxide coolant environment in nuclear power system. The traditional high-temperature tensile fixture has the following technical defects: in high-temperature environment, especially in supercritical carbon dioxide environment, the fixture material is prone to creep deformation, resulting in angular deviation of the upper and lower fixtures; the existing fixture usually uses single-point fixation or simple clamping to fix the sample, which is prone to looseness in high-temperature environment, resulting in uneven stress on the sample; there is no effective angle limiting mechanism, and the slight angle change of the fixture during the experiment will significantly affect the test results; the traditional fixture is prone to corrosion in supercritical carbon dioxide environment, affecting the service life and test accuracy. Therefore, it is urgent to develop a high-temperature tensile fixture with reasonable structure, strong stability, and especially suitable for supercritical carbon dioxide environment, to solve the drawbacks of the existing technology. SUMMARY

[0003] Embodiments of the present disclosure aim to at least solve one of the technical problems existing in the prior art, and provide an experimental device for tensile test under supercritical carbon dioxide environment.

[0004] Embodiments of the present disclosure provide an experimental device for tensile test under supercritical carbon dioxide environment, the experimental device comprising a high-pressure kettle, a first tensile member and a second tensile member connected to the top end and the bottom end of the high-pressure kettle respectively, a first fixture assembly, a second fixture assembly and a sheet-shaped sample test piece;

[0005] The first end of the first fixture assembly is connected to the first tensile member, and the first end of the second fixture assembly is connected to the second tensile member; the second end of the first fixture assembly and the second end of the second fixture assembly cooperate to clamp and fix the sheet-shaped sample test piece; wherein,

[0006] The second end of the first fixture assembly is provided with at least a pair of first positioning holes located at opposite positions, and the second end of the second fixture assembly is provided with a second positioning hole corresponding to each pair of first positioning holes, and a ceramic alloy rod is inserted into the first positioning hole and the corresponding second positioning hole to limit the angular deviation between the first fixture assembly and the second fixture assembly; the high-pressure kettle is used to provide a high-temperature and high-pressure environment of supercritical carbon dioxide.

[0007] Optionally, the first positioning hole comprises a first sub-positioning hole and a second sub-positioning hole, and the second positioning hole comprises a third sub-positioning hole and a fourth sub-positioning hole.

[0008] The first sub-positioning hole and the third sub-positioning hole correspondingly insert the ceramic alloy rod, and the second sub-positioning hole and the fourth sub-positioning hole correspondingly insert the ceramic alloy rod.

[0009] Optionally, the diameter tolerance of the first positioning hole and the second positioning hole is within ±0.01 mm.

[0010] Optionally, the sheet-shaped sample test piece comprises a connecting portion, a first clamping portion extending outwardly from a first end of the connecting portion, and a second clamping portion extending outwardly from a second end of the connecting portion.

[0011] The connecting portion, the first clamping portion, and the second clamping portion are all in sheet-shaped structures.

[0012] Optionally, the first clamp assembly comprises a first clamp body connected to the first stretching member at a first end, a first mounting portion extending outwardly from opposite sides of a second end of the first clamp body and formed with a first slot.

[0013] The first mounting portion is provided with a pair of first fixing holes penetrating through the thickness direction and communicating with the first slot, the first slot is used for accommodating the first clamping portion, and two pins are respectively inserted through the pair of first fixing holes and abut against the first clamping portion to fix the first clamping portion.

[0014] Optionally, a pair of first positioning holes are provided on the first mounting portion of opposite sides of the first slot along the length direction, the first positioning holes are blind holes, and the first positioning holes and the first fixing holes are not communicated with each other.

[0015] Optionally, the second clamp assembly comprises a second clamp body connected to the second stretching member at a first end, a second mounting portion extending outwardly from opposite sides of a second end of the second clamp body and formed with a second slot.

[0016] The second mounting portion is provided with a pair of second fixing holes penetrating through the thickness direction and communicating with the second slot, the second slot is used for accommodating the second clamping portion, and two pins are respectively inserted through the pair of second fixing holes and abut against the second clamping portion to fix the second clamping portion.

[0017] Optionally, a pair of second positioning holes are provided on the second mounting portion of opposite sides of the second slot along the length direction, the second positioning holes are blind holes, and the second positioning holes and the second fixing holes are not communicated with each other.

[0018] Optionally, the outer surface of the pin is provided with anti-slip texture to increase the coefficient of friction with the sheet-like sample specimen.

[0019] Optionally, the first clamping assembly and the second clamping assembly always keep the sheet-like sample specimen perpendicular to the horizontal line.

[0020] The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to the embodiments of this disclosure can achieve angular stability of the upper and lower clamping components, ensure reliable fixation of sheet sample specimens, and improve the accuracy and reliability of high-temperature tensile test data. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of an experimental apparatus for tensile testing in a supercritical carbon dioxide environment, according to an embodiment of the present disclosure.

[0022] Figure 2 for Figure 1 A schematic diagram of its breakdown. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1 and Figure 2 As shown, an experimental apparatus 100 for tensile testing in a supercritical carbon dioxide environment is provided. The apparatus 100 includes an autoclave and a first tensile member and a second tensile member (not shown) respectively connected to the top and bottom of the autoclave. The autoclave, the first tensile member, and the second tensile member are components used in conventional techniques for tensile testing in a supercritical carbon dioxide environment, and will not be described in detail here.

[0025] The experimental apparatus 100 further includes a first clamp assembly 110, a second clamp assembly 120, and a sheet-like sample specimen 130. A first end of the first clamp assembly 110 is connected to the first tensile member, and a first end of the second clamp assembly 120 is connected to the second tensile member. The second ends of the first clamp assembly 110 and the second clamp assembly 120 cooperate to clamp and fix the sheet-like sample specimen 130.

[0026] The second end of the first clamp assembly 110 is provided with a pair of first positioning holes located at opposite positions, and the second end of the second clamp assembly 120 is provided with a second positioning hole corresponding to each pair of first positioning holes. A ceramic alloy rod 140 is inserted into the first positioning hole and the corresponding second positioning hole to limit the angular deviation between the first clamp assembly 110 and the second clamp assembly 120. The autoclave is used to provide a high-temperature and high-pressure environment of supercritical carbon dioxide.

[0027] Specifically, as shown in Figure 1 and Figure 2 , the first clamp assembly 110 and the second clamp assembly 120 clamp and fix the sheet-shaped sample test piece 130 as experimental clamps. Both are basic load-bearing structures and are made of high-temperature-resistant alloy materials, which have good high-temperature mechanical properties and thermal stability and can maintain structural strength in a high-temperature and high-pressure supercritical carbon dioxide environment. The second end of the first clamp assembly 110 and the second clamp assembly 120 is provided with a structure suitable for the sheet-shaped sample test piece 130, which provides mounting space and clamping basis for the sheet-shaped sample test piece 130. By designing the ceramic alloy rod 140 to pass through the corresponding first positioning hole and second positioning hole, the angular deviation between the first clamp assembly and the second clamp assembly during the experiment can be effectively limited, ensuring that the sheet-shaped sample test piece is uniformly and stably stressed, and greatly improving the accuracy of experimental data.

[0028] The first clamp assembly and the second clamp assembly are made of high-temperature-resistant alloy materials, and the ceramic alloy rod has high-temperature-resistant and high-strength properties. The entire device can work stably in a high-temperature and high-pressure supercritical carbon dioxide environment, meeting the needs of material high-temperature mechanical property testing.

[0029] Further, the first positioning hole includes a first sub-positioning hole and a second sub-positioning hole (not shown), and the second positioning hole includes a third sub-positioning hole 141 and a fourth sub-positioning hole 142. The first sub-positioning hole and the third sub-positioning hole 141 correspondingly insert the ceramic alloy rod 140, and the second sub-positioning hole and the fourth sub-positioning hole 142 correspondingly insert the ceramic alloy rod 140.

[0030] The diameter tolerance of the first positioning hole and the second positioning hole is within ±0.01mm, ensuring precise fitting with the ceramic alloy rod 140.

[0031] Exemplarily, as shown in Figure 1 and Figure 2 , the sheet-shaped sample test piece 130 includes a connecting portion 131, a first clamping portion 132 extending outwardly from a first end of the connecting portion 131, and a second clamping portion 133 extending outwardly from a second end of the connecting portion 131. The connecting portion 131, the first clamping portion 132, and the second clamping portion 133 are all in a sheet-shaped structure.

[0032] The first clamp assembly 110 includes a first clamp body 111 connected to the first stretching member at a first end, and a first mounting portion 112 extending outward from opposite sides of a second end of the first clamp body 111 and formed with a first slot 200. The first mounting portion 112 is provided with a pair of first fixing holes 1121 penetrating a thickness direction thereof and communicating with the first slot 200, the first slot 200 being configured to accommodate the first clamping portion 132, and two pins 300 respectively penetrating the pair of first fixing holes 1121 and abutting against the first clamping portion 132 to fix the first clamping portion 132.

[0033] The first mounting portion 112 on opposite sides of the first slot 200 is provided with a pair of first positioning holes along a length direction thereof, the first positioning holes being blind holes. The first positioning holes and the first fixing holes 1121 are not communicated with each other.

[0034] The second clamp assembly 120 includes a second clamp body 121 connected to the second stretching member at a first end, and a second mounting portion 122 extending outward from opposite sides of a second end of the second clamp body 121 and formed with a second slot 300. The second mounting portion 122 is provided with a pair of second fixing holes 1221 penetrating a thickness direction thereof and communicating with the second slot 300, the second slot 300 being configured to accommodate the second clamping portion 133, and two pins 300 respectively penetrating the pair of second fixing holes 1221 and abutting against the second clamping portion 133 to fix the second clamping portion 133.

[0035] The second mounting portion 122 on opposite sides of the second slot 300 is provided with a pair of second positioning holes (i.e., third sub-positioning holes 141 and fourth sub-positioning holes 142) along a length direction thereof, the second positioning holes being blind holes. The second positioning holes and the second fixing holes 1221 are not communicated with each other.

[0036] The pins 300 are symmetrically arranged at a connecting portion of the sheet-shaped sample test piece 130 and the first and second mounting portions to achieve stable fixation. An outer surface of the pin 300 is further provided with anti-skid lines to increase a friction coefficient between the pin 300 and the sheet-shaped sample test piece 130. A first end of the first clamp body 111 and a first end of the second clamp body 121 are respectively provided with through holes penetrating a thickness direction thereof to respectively connect the first stretching member and the second stretching member, and stretching of the sheet-shaped sample test piece is achieved by relative movement of the first stretching member and the second stretching member.

[0037] Further, the first clamp assembly 110 and the second clamp assembly 120 always keep the sheet-shaped sample test piece 130 in a state perpendicular to a horizontal line.

[0038] As a specific example, the assembly process of the experimental device for the stretching experiment in the supercritical carbon dioxide environment is as follows:

[0039] The first clamp assembly and the second clamp assembly are cleaned to ensure that the first positioning hole and the second positioning hole are free of machining residues. Then, the hard ceramic alloy rod is inserted into the corresponding first positioning hole and second positioning hole, respectively, to ensure a tight fit and ensure that the ceramic alloy rod is in close contact with the hole wall without shaking.

[0040] The sheet-shaped sample specimen is fixed on the first clamp body by pin installation, and the sheet-shaped sample specimen is kept in a vertical position by its own weight.

[0041] Slowly move the second clamp assembly upward until the second fixed hole on the second clamp body moves to the corresponding position of the sheet-shaped sample specimen. At this time, a pair of pins are inserted into the second fixed hole to fix the sheet-shaped sample specimen. Turn on the motor and slowly move the second clamp assembly downward to apply a tensile force of 10-50 N to the sheet-shaped sample specimen to eliminate assembly gaps and check the fixing state of the sheet-shaped sample specimen to ensure that it is not loose.

[0042] The high-pressure kettle is used to create a supercritical carbon dioxide environment with high temperature and high pressure inside, and the target temperature and pressure (650℃, 20MPa) are reached and stabilized for the stretching experiment.

[0043] The ceramic alloy rod limits the relative rotation of the first clamp assembly and the second clamp assembly, ensuring that the sheet-shaped sample specimen is subjected to axial stress. During the experiment, the tensile force acts on the first clamp assembly and the second clamp assembly. Due to the limiting action of the ceramic alloy rod, the angle of the first clamp assembly and the second clamp assembly does not deviate, and the sheet-shaped sample specimen always maintains a stable stress state, so that the test data can accurately reflect the mechanical properties of the material in a high-temperature environment.

[0044] Experimental application: During the temperature and pressure increasing process, the flow of the medium in the high-pressure kettle and the change of the pressure will exert a certain external force on the sheet-shaped sample specimen, the first clamp assembly, the second clamp assembly, and the stretching shaft as a whole. With the limiting action of the ceramic alloy rod, the relative angle of the first clamp assembly and the second clamp assembly is stable, and the sheet-shaped sample specimen will not loosen due to the relative position movement of the first clamp assembly and the second clamp assembly. After reaching the specified temperature and pressure, the experiment is started, and the equipment collects real-time mechanical data during the stretching process. After the experiment is completed, the data is analyzed and processed to obtain the mechanical performance indicators of the material in the supercritical carbon dioxide environment.

[0045] It is understood that the above embodiments are only exemplary for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. An experimental apparatus for tensile testing in a supercritical carbon dioxide environment, characterized in that, The experimental apparatus includes an autoclave, a first tensile member and a second tensile member respectively connected to the top and bottom of the autoclave, a first clamp assembly, a second clamp assembly, and a sheet-like sample specimen. The first end of the first clamping assembly is connected to the first tensile member, and the first end of the second clamping assembly is connected to the second tensile member; the second ends of the first clamping assembly and the second clamping assembly cooperate to clamp and fix the sheet-like sample specimen; wherein... The second end of the first clamping assembly has at least a pair of first positioning holes located at diagonal positions, and the second end of the second clamping assembly has a second positioning hole corresponding to each pair of first positioning holes. Ceramic alloy rods are inserted into the first positioning holes and the corresponding second positioning holes to limit the angular offset between the first clamping assembly and the second clamping assembly. The autoclave is used to provide a high temperature and high pressure environment for supercritical carbon dioxide.

2. The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to claim 1, characterized in that, The first positioning hole includes a first sub-positioning hole and a second sub-positioning hole, and the second positioning hole includes a third sub-positioning hole and a fourth sub-positioning hole; The ceramic alloy rod is inserted into the first sub-positioning hole and the third sub-positioning hole respectively, and the ceramic alloy rod is inserted into the second sub-positioning hole and the fourth sub-positioning hole respectively.

3. The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to claim 1, characterized in that, The diameter tolerance of the first positioning hole and the second positioning hole is within ±0.01mm.

4. The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to any one of claims 1 to 3, characterized in that, The sheet-like sample specimen includes a connecting portion, a first snap-fit ​​portion extending outward from a first end of the connecting portion, and a second snap-fit ​​portion extending outward from a second end of the connecting portion. The connecting part, the first snap-fit ​​part, and the second snap-fit ​​part are all sheet-like structures.

5. The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to claim 4, characterized in that, The first clamp assembly includes a first clamp body with a first end connected to the first tension member, and a first mounting portion extending outward from opposite sides of the second end of the first clamp body and forming a first slit; The first mounting part has a pair of first fixing holes that extend through its thickness direction and communicate with the first slit. The first slit is used to accommodate the first snap-fit ​​part. Two pins pass through the pair of first fixing holes and abut against the first snap-fit ​​part to fix the first snap-fit ​​part.

6. The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to claim 5, characterized in that, A pair of first positioning holes are provided on the first mounting portions on opposite sides of the first slit along its length direction. The first positioning holes are blind holes. The first positioning holes and the first fixing holes are not connected to each other.

7. The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to claim 6, characterized in that, The second clamp assembly includes a second clamp body with a first end connected to the second tension member, and a second mounting portion extending outward from opposite sides of the second end of the second clamp body and forming a second slit; The second mounting part has a pair of second fixing holes that extend through its thickness direction and communicate with the second slit. The second slit is used to accommodate the second snap-fit ​​part. Two pins pass through the pair of second fixing holes and abut against the second snap-fit ​​part to fix the second snap-fit ​​part.

8. The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to claim 7, characterized in that, A pair of second positioning holes are provided on the second mounting portions on opposite sides of the second slit along its length direction. The second positioning holes are blind holes. The second positioning holes and the second fixing holes are not connected to each other.

9. The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to claim 7, characterized in that, The outer surface of the pin is provided with anti-slip texture to increase the coefficient of friction with the sheet sample specimen.

10. The experimental apparatus for tensile testing in a supercritical carbon dioxide environment according to claim 1, characterized in that, The first clamping assembly and the second clamping assembly always keep the sheet-shaped sample specimen perpendicular to the horizontal line.

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