A nanoindentation testing device

Abstract

The present invention relates to the field of nanoindentation testing technology. The present invention discloses a nanoindentation testing device, comprising a frame, an indentation testing mechanism, a stage, a laser light source, a sealed chamber, an atmosphere simulation mechanism and a vacuum mechanism, wherein the indentation testing mechanism comprises an indenter, a drive system and a measurement system, the indenter moves along a vertical axis; the laser light source faces the stage; the sealed chamber and the indenter are located on the same vertical axis, the stage is located in the sealed chamber, the indenter extends into the sealed chamber from the indenter avoidance port, the sealed chamber is provided with a laser avoidance window, the laser avoidance window is located on the laser light path, and the sealed chamber is also provided with a gas inlet and a gas outlet. The present invention can achieve non-contact local heating by directly acting on a sample to be tested in the sealed chamber through the laser light source; through the cooperation of the sealed chamber with the atmosphere simulation mechanism and the vacuum mechanism, the sample to be tested can be tested under vacuum, inert atmosphere or specific working atmosphere conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of nanoindentation testing, and in particular to a nanoindentation testing device. Background Art

[0002] The rapid development of materials science in extreme environmental applications has placed higher demands on testing the mechanical properties of materials under complex conditions such as high temperatures and corrosive media. Traditional nanoindentation testing techniques primarily utilize substrate heating, relying on heat conduction to achieve temperature loading on the sample under test. This heating method exhibits a delayed thermal response, and heat easily dissipates in an open heating environment, leading to uneven temperature distribution across the sample under test. Furthermore, existing nanoindentation testing methods lack reliable, sealed environments and integrated atmospheric simulation systems for testing in specific working atmospheres, such as corrosive conditions. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0004] The present invention provides a nanoindentation testing device, comprising:

[0005] frame;

[0006] An indentation testing mechanism, comprising an indenter, a drive system, and a measurement system. The indenter is mounted on a frame and moves along a vertical axis. The drive system is in transmission connection with the indenter and is used to drive the indenter toward or away from the sample to be tested. The measurement system is electrically connected to the indenter and is used to obtain indentation test information.

[0007] A loading platform, located below the indenter and used for placing a sample to be tested;

[0008] A laser light source, the laser light source being mounted on the frame and facing the stage;

[0009] A sealed chamber, wherein the sealed chamber is mounted on the frame, the sealed chamber and the pressure head are located on the same vertical axis, a closable sample entrance and exit are provided on the sealed chamber, the stage is located in the sealed chamber, a pressure head avoidance opening is provided on the top of the sealed chamber, the pressure head extends into the sealed chamber from the pressure head avoidance opening, a laser avoidance window is provided in the sealed chamber, the laser avoidance window is used to avoid the incident laser light path, and a gas inlet and a gas outlet are also provided on the sealed chamber;

[0010] An atmosphere simulation mechanism, the atmosphere simulation mechanism being connected to the sealed chamber via the gas inlet, the atmosphere simulation mechanism being used to create a working atmosphere environment required by the sample in the sealed chamber;

[0011] A vacuum mechanism is connected to the sealed chamber through the gas outlet, and is used to extract the gas in the sealed chamber.

[0012] The beneficial effects of the present invention are as follows: the present invention directly acts on the sample to be tested in the sealed chamber through the laser light source, which can achieve non-contact local heating and avoid the thermal hysteresis effect and temperature gradient interference caused by traditional resistance heating; through the cooperation of the sealed chamber with the atmosphere simulation mechanism and the vacuum mechanism, the sample to be tested can be tested under vacuum, inert atmosphere or specific working atmosphere conditions.

[0013] Furthermore, a magnetic fluid sealing mechanism is provided on the pressure head avoidance port, and the magnetic fluid sealing mechanism includes a fixed seat, a magnetic fluid, and a permanent magnet group. A sealed cavity is provided in the fixed seat, and the sealed cavity and the pressure head are located on the same vertical axis. After the pressure head passes through the sealed cavity, it extends into the sealed chamber from the pressure head avoidance port; a magnetic fluid reservoir is provided on the inner wall of the fixed seat, and the magnetic fluid is filled into the magnetic fluid reservoir; a permanent magnet receiving groove is provided on the outer wall of the fixed seat, and the permanent magnet group is arranged in the permanent magnet receiving groove. The present invention provides a magnetic fluid sealing mechanism, wherein the magnetic fluid forms a sealing structure similar to a "liquid O-ring" under the action of the magnetic field generated by the permanent magnet group, which can effectively block the gap between the pressure head and the sealed cavity, realize non-contact dynamic sealing, and prevent harmful gases in the sealed chamber from leaking from the pressure head avoidance port.

[0014] Furthermore, the permanent magnet receiving slot is an annular permanent magnet receiving slot, and the permanent magnet group is arranged in a Halbach array. The present invention utilizes the magnetic field optimization characteristics of the Halbach array to significantly enhance the magnetic field strength in the magnetic fluid reservoir area, thereby improving the magnetic fluid sealing effect. At the same time, the backside magnetic field is offset, effectively reducing electromagnetic interference caused by leakage magnetic flux on other precision components in the device.

[0015] Furthermore, the magnetic fluid sealing mechanism further includes a first cover plate and a second cover plate, which enclose and seal the permanent magnet housing slot. The present invention utilizes the cover plate structure to form a physical sealing barrier around the fixed seat of the magnetic fluid sealing mechanism, preventing external dust and moisture from invading the permanent magnet housing slot. The cover plate structure is removable, facilitating removal or replacement of the permanent magnet assembly during device maintenance.

[0016] Furthermore, the ram is provided with a bellows outer sleeve, one end of which is fixed to the top of the sealed chamber, and the end of the bellows, whose inner cavity is remote from the sealed chamber, is connected to the free end of the ram. In the present invention, the bellows' elastic deformation allows it to closely conform to the contact surface between the ram and the sealed chamber, effectively preventing gas leakage from the sealed chamber. When the ram moves along a vertical axis, the bellows can compensate for axial displacement through the expansion and contraction of the corrugated structure, adapting to the displacement changes during ram movement and ensuring a continuous seal.

[0017] Furthermore, the nanoindentation testing device also includes an optical path processing mechanism, which is located in the sealed chamber. The optical path processing mechanism includes a first beam splitter, a second beam splitter, a third beam splitter, a first reflector, a second reflector, a third reflector and a fourth reflector. The first reflector, the second reflector, the third reflector and the fourth reflector are respectively located around the object stage. The emitting end of the laser light source faces the first beam splitter, the first beam splitter is used to forward the laser emitted by the laser light source to the second beam splitter and the third beam splitter, the second beam splitter is used to forward the laser forwarded by the first beam splitter to the first reflector and the second reflector, and the third beam splitter is used to forward the laser forwarded by the first beam splitter to the third reflector and the fourth reflector. The lasers reflected by the first reflector, the second reflector, the third reflector and the fourth reflector converge to the storage area of ​​the object stage. The first reflector, the second reflector, the third reflector and the fourth reflector of the present invention are symmetrically arranged, so that the laser energy can evenly cover the sample surface from four directions, avoiding local overheating or temperature gradient of the sample caused by irradiation from a single direction, and significantly improving the uniformity of the thermal field distribution.

[0018] Furthermore, the bottoms of the first beam splitter, the second beam splitter, the third beam splitter, the first reflector, the second reflector, the third reflector, and the fourth reflector are respectively formed with downwardly extending positioning blocks, the positioning blocks are square positioning blocks, seven positioning holes are provided in the sealed chamber, the hole shape of the positioning holes matches the shape of the positioning blocks, and the first beam splitter, the second beam splitter, the third beam splitter, the first reflector, the second reflector, the third reflector, and the fourth reflector are respectively detachably connected to the corresponding positioning holes through the positioning blocks. All the beam splitters and reflectors in the present invention are detachable for easy replacement or maintenance. In addition, the positioning blocks and positioning holes are designed to be square in shape, which facilitates positioning and installation while ensuring that the mirror position will not shift left or right during use, thereby ensuring the accuracy of the laser light path.

[0019] Furthermore, a transparent protective layer is provided on the mirror surfaces of the first beam splitter, the second beam splitter, the third beam splitter, the first reflector, the second reflector, the third reflector, and the fourth reflector. The transparent protective layer is a silicon dioxide transparent protective layer. By providing the silicon dioxide transparent protective layer on the mirror surfaces of the relevant beam splitters and reflectors, the present invention prevents the mirror surfaces from being corroded and affecting their reliability when the device operates in a corrosive atmosphere.

[0020] Furthermore, the gas inlet includes a first gas inlet and a second gas inlet, each of which is connected to the atmosphere simulation mechanism. The first gas inlet is used to introduce simulated atmosphere gas, and the second gas inlet is used to introduce clean gas. The present invention provides separate first and second gas inlets for the intake of simulated atmosphere gas (e.g., hydrogen sulfide, chlorine) and clean gas (e.g., argon, nitrogen), respectively. This physically isolated, independent gas passageway prevents cross-contamination between the two gases in the pipeline. Furthermore, this arrangement allows for rapid switching of gas types during operation without the need for manual reconnection or replacement of gas cylinders, thereby improving work efficiency.

[0021] Furthermore, the sealed chamber is also provided with an air pressure monitoring system and an air pressure balancing valve. The air pressure monitoring system is electrically connected to the atmosphere simulation mechanism, the vacuum mechanism, and the air pressure balancing valve, respectively. The air pressure monitoring system is used to obtain air pressure information within the sealed chamber, and the air pressure balancing valve is used to balance the air pressure inside and outside the sealed chamber. By providing the air pressure monitoring system and the air pressure balancing valve, the present invention can monitor and adjust the air pressure within the sealed chamber in real time, avoiding test errors caused by sudden pressure changes and preventing overpressure within the sealed chamber.

[0022] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0024] Figure 1 This is a schematic structural diagram of a nanoindentation testing device according to an embodiment of the present invention;

[0025] Figure 2 A cross-sectional view of a nanoindentation testing device according to an embodiment of the present invention;

[0026] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0027] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0028] Figure 5 This is a schematic diagram of the laser light path of a nanoindentation testing device according to an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of disassembling the second reflector according to an embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of the back structure of a nanoindentation testing device according to an embodiment of the present invention;

[0031] Figure 8 for Figure 7 Enlarged view of point C in the middle.

[0032] In the accompanying drawings: 100-frame; 201-pressure head; 202-drive system; 300-object stage; 400-laser light source; 500-sealed chamber; 501-sample entrance and exit; 502-laser avoidance window; 503-first gas inlet; 504-second gas inlet; 505-gas outlet; 506-air pressure balance valve; 507-positioning socket; 600-magnetic fluid sealing mechanism; 601-fixed seat; 602-magnetic fluid storage tank; 603-permanent magnet storage tank; 604-first cover plate; 605-second cover plate; 700-bellows; 801-first spectrometer; 802-second spectrometer; 803-third spectrometer; 804-first reflector; 805-second reflector; 806-third reflector; 807-fourth reflector; 808-positioning plug; 900-gas monitoring system. DETAILED DESCRIPTION

[0033] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0035] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0036] The following combination Figures 1 to 8 Embodiments of the present invention are described.

[0037] An embodiment of the present invention provides a nanoindentation testing device, comprising:

[0038] Rack 100;

[0039] An indentation testing mechanism, comprising an indenter 201, a drive system 202, and a measurement system. The indenter 201 is mounted on the frame 100 and moves along a vertical axis. The drive system 202 is in transmission connection with the indenter 201 and is used to drive the indenter 201 toward or away from the sample to be tested. The measurement system is electrically connected to the indenter 201 and is used to obtain indentation test information.

[0040] The stage 300 is located below the indenter 201 and is used to place a sample to be tested;

[0041] A laser light source 400 is mounted on the frame 100 and faces the stage 300;

[0042] A sealed chamber 500 is mounted on the frame 100. The sealed chamber 500 and the indenter 201 are located on the same vertical axis. A closable sample inlet and outlet 501 is provided on the sealed chamber 500. The stage 300 is located within the sealed chamber 500. A indenter avoidance opening is provided at the top of the sealed chamber 500. The indenter 201 extends into the sealed chamber 500 through the indenter avoidance opening. A laser avoidance window 502 is provided in the sealed chamber 500. The laser avoidance window 502 is used to avoid the incident laser light path. The sealed chamber 500 is also provided with a gas inlet and a gas outlet 505.

[0043] An atmosphere simulation mechanism, the atmosphere simulation mechanism is connected to the sealed chamber 500 through the gas inlet, and the atmosphere simulation mechanism is used to create a working atmosphere environment required by the sample in the sealed chamber 500;

[0044] A vacuum mechanism is connected to the sealed chamber 500 through the gas outlet 505 , and is used to extract the gas in the sealed chamber 500 .

[0045] In the indentation testing mechanism of this embodiment, the drive system 202 is hydraulically driven; the measurement system includes a pressure sensor and a displacement sensor, the pressure sensor is used to obtain the load information applied by the indenter 201 to the sample, and the displacement sensor is used to obtain the displacement information of the indenter 201 on the sample surface; the laser avoidance window 502 in the sealed chamber 500 is made of quartz glass, which allows laser penetration and is resistant to high temperature and corrosive gases; the atmosphere simulation mechanism is an external gas cylinder corresponding to the specific working atmosphere conditions of the sample to be tested; the vacuum mechanism is a vacuum pump.

[0046] In this embodiment, the laser light source 400 directly acts on the sample to be tested in the sealed chamber 500, thereby achieving non-contact local heating and avoiding the thermal hysteresis effect and temperature gradient interference caused by traditional resistance heating; through the cooperation of the sealed chamber 500 with the atmosphere simulation mechanism and the vacuum mechanism, the sample to be tested can be tested under vacuum, inert atmosphere or specific working atmosphere conditions.

[0047] Furthermore, a magnetic fluid sealing mechanism 600 is provided on the pressure head avoidance port, and the magnetic fluid sealing mechanism 600 includes a fixed seat 601, a magnetic fluid and a permanent magnet group. A sealed cavity is opened in the fixed seat 601, and the sealed cavity and the pressure head 201 are located on the same vertical axis. After the pressure head 201 passes through the sealed cavity, it extends into the sealed chamber 500 from the pressure head 201 avoidance port; a magnetic fluid storage tank 602 is opened on the inner wall of the fixed seat 601, and the magnetic fluid is filled into the magnetic fluid storage tank 602; a permanent magnet accommodating tank 603 is opened on the outer wall of the fixed seat 601, and the permanent magnet group is arranged in the permanent magnet accommodating tank 603. This embodiment provides a magnetic fluid sealing mechanism 600, in which the magnetic fluid forms a sealing structure similar to a "liquid O-ring" under the action of the magnetic field generated by the permanent magnet group, which can effectively seal the gap between the pressure head 201 and the sealing cavity, realize non-contact dynamic sealing, and prevent harmful gases in the sealing chamber 500 from leaking from the avoidance port of the pressure head 201.

[0048] Furthermore, the permanent magnet receiving slot 603 is an annular permanent magnet receiving slot, and the permanent magnet group is arranged in a Halbach array. This embodiment utilizes the magnetic field optimization characteristics of the Halbach array to significantly enhance the magnetic field strength in the magnetic fluid reservoir 602 area, thereby improving the magnetic fluid sealing effect. At the same time, the back magnetic field is offset, effectively reducing the electromagnetic interference of leakage magnetic field on other precision components in the device.

[0049] Furthermore, the magnetic fluid sealing mechanism 600 further includes a first cover plate 604 and a second cover plate 605, which enclose and seal the permanent magnet receiving slot 603. In this embodiment, the cover plate structure forms a physical sealing barrier around the fixing seat 601 of the magnetic fluid sealing mechanism 600, preventing external dust and moisture from invading the permanent magnet receiving slot 603. The cover plate structure is removable, facilitating removal or replacement of the permanent magnet assembly during device maintenance.

[0050] Furthermore, the pressure head 201 is provided with a bellows 700, one end of which is fixed to the top of the sealed chamber 500, and the end of the bellows 700, whose inner cavity is away from the sealed chamber 500, is connected to the free end of the pressure head 201. In this embodiment, the bellows 700's elastic deformation capability allows it to closely conform to the contact surface between the pressure head 201 and the sealed chamber 500, effectively preventing gas leakage from the sealed chamber 500. When the pressure head 201 moves along the vertical axis, the bellows 700 can compensate for axial displacement through the expansion and contraction of the corrugated structure, adapting to the displacement changes of the pressure head 201 during movement and ensuring a continuous sealing state.

[0051] Furthermore, the nanoindentation testing device further includes an optical path processing mechanism, which is located in the sealed chamber 500. The optical path processing mechanism includes a first beam splitter 801, a second beam splitter 802, a third beam splitter 803, a first reflector 804, a second reflector 805, a third reflector 806, and a fourth reflector 807. The first reflector 804, the second reflector 805, the third reflector 806, and the fourth reflector 807 are respectively located around the stage 300. The emitting end of the laser light source 400 is facing the first beam splitter 801. The first beam splitter 80 1 is used to forward the laser light emitted by the laser light source 400 to the second beam splitter 802 and the third beam splitter 803. The second beam splitter 802 is used to forward the laser light forwarded by the first beam splitter 801 to the first reflector 804 and the second reflector 805. The third beam splitter 803 is used to forward the laser light forwarded by the first beam splitter 801 to the third reflector 806 and the fourth reflector 807. The laser light reflected by the first reflector 804, the second reflector 805, the third reflector 806, and the fourth reflector 807 converges to the storage area of ​​the stage 300. In this embodiment, the first reflector 804, the second reflector 805, the third reflector 806, and the fourth reflector 807 are arranged symmetrically, enabling the laser energy to evenly cover the sample surface from four directions, avoiding local overheating or temperature gradients in the sample caused by irradiation from a single direction, and significantly improving the uniformity of the thermal field distribution.

[0052] Furthermore, the bottoms of the first beam splitter 801, the second beam splitter 802, the third beam splitter 803, the first reflector 804, the second reflector 805, the third reflector 806 and the fourth reflector 807 are respectively formed with downwardly extending positioning blocks, and the positioning blocks 808 are square positioning blocks. Seven positioning holes 507 are provided in the sealed chamber 500, and the hole shape of the positioning holes 507 matches the shape of the positioning blocks 808. The first beam splitter 801, the second beam splitter 802, the third beam splitter 803, the first reflector 804, the second reflector 805, the third reflector 806 and the fourth reflector 807 are respectively detachably connected to the corresponding positioning holes 507 through the positioning blocks 808. In this embodiment, all beam splitters and reflectors are removable for easy replacement or maintenance. Furthermore, the positioning insert 808 and positioning socket 507 are designed in a square shape, facilitating positioning and installation while ensuring that the mirror surface does not shift left or right during use, thereby ensuring the accuracy of the laser light path. Furthermore, the mirror surfaces of the first beam splitter 801, the second beam splitter 802, the third beam splitter 803, the first reflector 804, the second reflector 805, the third reflector 806, and the fourth reflector 807 are all provided with a transparent protective layer, which is a silicon dioxide transparent protective layer. By providing a silicon dioxide transparent protective layer on the mirror surfaces of the relevant beam splitters and reflectors in this embodiment, corrosion of the mirror surfaces, which could affect their reliability, is prevented when the device operates in a corrosive atmosphere. Furthermore, the gas inlet includes a first gas inlet 503 and a second gas inlet 504, each of which is connected to the atmosphere simulation mechanism. The first gas inlet 503 is used to introduce simulated atmosphere gas, and the second gas inlet 504 is used to introduce clean gas. This embodiment provides separate first and second gas inlets 503, 504 for the intake of simulated atmosphere gas and clean gas, respectively. This physically isolated, independent gas channel prevents cross-contamination between the two gases in the pipeline. Furthermore, this arrangement allows for rapid switching between gas types during operation without the need for manual reconnection or replacement of gas cylinders, thereby improving work efficiency.

[0053] Furthermore, the sealed chamber 500 is provided with an air pressure monitoring system and an air pressure balancing valve 506. The air pressure monitoring system is electrically connected to the atmosphere simulation mechanism, the vacuum mechanism, and the air pressure balancing valve 506, respectively. The air pressure monitoring system is used to obtain air pressure information within the sealed chamber 500, and the air pressure balancing valve 506 is used to balance the air pressure inside and outside the sealed chamber 500. Through the provision of the air pressure monitoring system and the air pressure balancing valve 506, this embodiment can monitor and adjust the air pressure within the sealed chamber 500 in real time, avoiding test errors caused by sudden pressure changes and preventing overpressure within the sealed chamber 500.

[0054] Furthermore, the nanoindentation testing apparatus also includes a gas monitoring system 900, which is used to obtain information about the composition and concentration of the gas outside the sealed chamber 500. This embodiment uses the gas monitoring system 900 to monitor the composition of the ambient gas outside the sealed chamber 500 in real time, thereby determining whether there is any leakage of harmful gas within the sealed chamber 500.

[0055] Furthermore, the nanoindentation testing apparatus further includes a control unit, which is electrically connected to the drive system 202, the measurement system, the laser light source 400, the vacuum mechanism, the atmosphere simulation mechanism, the air pressure monitoring system, and the gas monitoring system 900. This embodiment integrates the drive system 202, the measurement system, the laser light source 400, the vacuum mechanism, the atmosphere simulation mechanism, the air pressure monitoring system, and the gas monitoring system through the control unit, thereby achieving synchronous operation and closed-loop feedback of each link.

[0056] The above specifically describes the preferred embodiments of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A nanoindentation testing device, characterized in that: include: frame; An indentation testing mechanism, comprising an indenter, a drive system, and a measurement system. The indenter is mounted on a frame and moves along a vertical axis. The drive system is in transmission connection with the indenter and is used to drive the indenter toward or away from the sample to be tested. The measurement system is electrically connected to the indenter and is used to obtain indentation test information. A loading platform, located below the indenter and used for placing a sample to be tested; A laser light source, the laser light source being mounted on the frame and facing the stage; A sealed chamber, wherein the sealed chamber is mounted on the frame, the sealed chamber and the pressure head are located on the same vertical axis, a closable sample entrance and exit are provided on the sealed chamber, the stage is located in the sealed chamber, a pressure head avoidance opening is provided on the top of the sealed chamber, the pressure head extends into the sealed chamber from the pressure head avoidance opening, a laser avoidance window is provided in the sealed chamber, the laser avoidance window is used to avoid the incident laser light path, and a gas inlet and a gas outlet are also provided on the sealed chamber; An atmosphere simulation mechanism, the atmosphere simulation mechanism being connected to the sealed chamber via the gas inlet, the atmosphere simulation mechanism being used to create a working atmosphere environment required by the sample in the sealed chamber; a vacuum mechanism, the vacuum mechanism being connected to the sealed chamber via the gas outlet, and the vacuum mechanism being used to extract the gas in the sealed chamber; The optical path processing mechanism is located in the sealed chamber and includes a first beam splitter, a second beam splitter, a third beam splitter, a first reflector, a second reflector, a third reflector and a fourth reflector. The first reflector, the second reflector, the third reflector and the fourth reflector are respectively located around the stage. The emission end of the laser light source faces the first beam splitter. The first beam splitter is used to forward the laser light emitted by the laser light source to the second beam splitter and the third beam splitter. The second beam splitter is used to forward the laser light emitted by the laser light source to the second beam splitter and the third beam splitter. The optical mirror is used to forward the laser forwarded by the first beam splitter to the first reflector and the second reflector, and the third beam splitter is used to forward the laser forwarded by the first beam splitter to the third reflector and the fourth reflector. The lasers reflected by the first reflector, the second reflector, the third reflector and the fourth reflector converge to the placement area of ​​the stage; the first reflector, the second reflector, the third reflector and the fourth reflector adopt a symmetrical layout, which can enable the laser energy to evenly cover the sample surface from four directions.

2. The nanoindentation testing device according to claim 1, characterized in that: A magnetic fluid sealing mechanism is provided on the pressure head avoidance port, and the magnetic fluid sealing mechanism includes a fixed seat, a magnetic fluid and a permanent magnet group. A sealed cavity is provided in the fixed seat, and the sealed cavity and the pressure head are located on the same vertical axis. After the pressure head passes through the sealed cavity, it extends into the sealed cavity from the pressure head avoidance port; a magnetic fluid storage tank is provided on the inner wall of the fixed seat, and the magnetic fluid is filled into the magnetic fluid storage tank; a permanent magnet accommodating tank is provided on the outer wall of the fixed seat, and the permanent magnet group is arranged in the permanent magnet accommodating tank.

3. The nanoindentation testing device according to claim 2, characterized in that: The permanent magnet accommodating groove is an annular permanent magnet accommodating groove, and the permanent magnet group is arranged in a Halbach array.

4. The nanoindentation testing device according to claim 3, characterized in that: The magnetic fluid sealing mechanism further includes a first cover plate and a second cover plate, and the first cover plate and the second cover plate enclose and seal the permanent magnet accommodating groove.

5. The nanoindentation testing device according to claim 1, characterized in that: The outer sleeve of the pressure head is provided with a bellows, one end of the bellows is fixed to the top of the sealed chamber, and the end of the inner cavity of the bellows away from the sealed chamber is connected to the free end of the pressure head.

6. The nanoindentation testing device according to claim 1, characterized in that: The bottoms of the first beam splitter, the second beam splitter, the third beam splitter, the first reflector, the second reflector, the third reflector and the fourth reflector are respectively formed with downwardly extending positioning blocks, the positioning blocks are square positioning blocks, seven positioning holes are provided in the sealed chamber, the hole shape of the positioning holes matches the shape of the positioning blocks, and the first beam splitter, the second beam splitter, the third beam splitter, the first reflector, the second reflector, the third reflector and the fourth reflector are respectively detachably connected to the corresponding positioning holes through the positioning blocks.

7. The nanoindentation testing device according to claim 1, characterized in that: A transparent protective layer is provided on the mirror surfaces of the first beam splitter, the second beam splitter, the third beam splitter, the first reflector, the second reflector, the third reflector and the fourth reflector, and the transparent protective layer is a silicon dioxide transparent protective layer.

8. The nanoindentation testing device according to claim 1, characterized in that: The gas inlet includes a first gas inlet and a second gas inlet, the first gas inlet and the second gas inlet are respectively connected to the atmosphere simulation mechanism, the first gas inlet is used to introduce simulated atmosphere gas, and the second gas inlet is used to introduce clean gas.

9. The nanoindentation testing device according to claim 1, characterized in that: The sealed chamber is also provided with an air pressure monitoring system and an air pressure balancing valve. The air pressure monitoring system is electrically connected to the atmosphere simulation mechanism, the vacuum mechanism and the air pressure balancing valve respectively. The air pressure monitoring system is used to obtain the air pressure information in the sealed chamber, and the air pressure balancing valve is used to balance the air pressure inside and outside the sealed chamber.

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