Multi-energy field assisted nano-indentation processing device and test method thereof

Abstract

The present application relates to the technical field of precision machining, and particularly relates to a multi-energy field assisted nano indentation machining device and a test method thereof, which comprises a base, a three-axis moving mechanism, a main shaft clamp, an ultrasonic vibration module, a laser assisted heating module, an electric field applying module and an electric insulation system. The ultrasonic vibration module transmits high-frequency vibration to the tip of the indenter along the indentation direction through the amplitude bar; the laser assisted heating module focuses the laser beam on the contact area between the indenter and the workpiece for local heating; the electric field applying module applies a pulsed electric field to the workpiece through a pair of electrodes; and the electric insulation system restricts the electric field to the internal machining area of the workpiece. During machining, the three energy fields are coupled synchronously in the micro contact area between the indenter and the workpiece, and the ultrasonic power, the laser power and the electric field intensity are dynamically adjusted according to the initial contact stage, the indentation forming stage, the load maintaining stage and the unloading stage of the indenter, so as to effectively reduce the machining load, inhibit crack propagation, and improve the surface quality of hard and brittle material nano indentation machining and the accuracy of mechanical parameter test.

Description

Technical Field

[0001] This invention relates to the field of precision machining technology, specifically to a multi-energy field assisted nanoindentation machining device and its testing method. Background Technology

[0002] Nanoindentation, as a high-precision micro / nano mechanical testing and processing method, can obtain various mechanical property parameters such as hardness, elastic modulus, and fracture toughness of materials at the micro / nano scale, and has been widely used in bulk materials, thin films, and coatings. However, traditional nanoindentation technology still has many limitations in practical applications: for hard and brittle materials (such as single-crystal silicon carbide and gallium nitride), crack propagation and subsurface damage are easily generated under a single mechanical load, resulting in a decrease in the quality of the processed surface; at the same time, the surface condition of the material has a significant impact on the accuracy of the test results, and there are problems such as poor test repeatability and difficulty in accurately locating the indentation position.

[0003] To improve the nanoindentation processing effect, researchers have attempted to introduce auxiliary energy fields. Studies on ultrasonic vibration-assisted processing have shown that high-frequency vibration can reduce processing friction, increase material removal rate, and effectively reduce subsurface damage. Laser-assisted heating technology softens materials through localized high temperatures, helping to improve the material's plastic deformation capacity. Electric field-assisted processing utilizes the electroplastic effect, promoting dislocation movement through pulsed current to improve material formability. However, in existing technologies, these auxiliary methods mostly employ a single energy field, failing to achieve synergistic coupling of multiple energy fields. For example, while ultrasonic vibration can reduce processing load, its softening effect on materials is limited; while laser heating can locally soften materials, it is difficult to control the microstructure; and while electric field assistance can improve plasticity, its mechanism of action at ultra-high strain rates has not been fully explored. Furthermore, existing devices have loose structures, failing to guarantee the precise synergistic effect of lasers, ultrasound, and electric fields at the nanoscale, making it difficult to meet the high-quality micro / nano processing requirements of hard, brittle, and difficult-to-machine materials.

[0004] To address the shortcomings of the existing technologies, this invention aims to provide a multi-energy field assisted nanoindentation processing device to solve the problem of crack propagation in hard and brittle materials caused by a single mechanical load in existing nanoindentation devices. It overcomes the limitations of the single energy field's limited auxiliary effect and inability to coordinate and couple, and achieves synchronous coupling of ultrasonic vibration, laser heating, and electric field excitation, thereby reducing processing load, suppressing crack propagation, and improving the surface quality of the processed material. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-energy field assisted nanoindentation processing device and its testing method. By integrating ultrasonic vibration, laser heating and pulsed electric field modules into the contact area between the indenter and the workpiece, the in-situ synchronous synergistic effect of force-heat-electric multi-energy fields is achieved, which significantly suppresses the processing cracks of hard and brittle materials.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0007] A multi-energy field assisted nanoindentation processing device includes a base, a workpiece fixture mounted on an operating table, and a three-axis moving mechanism for driving the spindle fixture to move relative to the operating table in the X, Y, and Z directions. The device further includes:

[0008] An ultrasonic vibration module is mounted on the spindle fixture. The output end of the ultrasonic vibration module is equipped with a pressure head. The ultrasonic vibration module is used to apply high-frequency vibration parallel to the pressing direction to the pressure head.

[0009] A laser-assisted heating module is installed on the operating table. The output light path of the laser-assisted heating module is configured to be aligned with the contact area between the tip of the pressure head and the workpiece, for local heating of the area.

[0010] An electric field application module includes electrodes disposed on the operating table and in electrical contact with the workpiece, for constructing a pulsed electric field in the processing area;

[0011] And an electrical insulation system for electrically isolating the workpiece from the base and the metal parts of the workpiece clamp;

[0012] The ultrasonic vibration module, the laser-assisted heating module, and the electric field application module are configured to simultaneously apply high-frequency vibration, local heating, and pulsed electric field to the contact area between the tip of the indenter and the workpiece, so as to form an in-situ synergistic effect of force-heat-electric multi-energy field in the contact area.

[0013] Furthermore, the ultrasonic vibration module includes:

[0014] Ultrasonic vibration transducer;

[0015] An amplitude transformer, whose input end is connected to the output end of the ultrasonic vibration transducer and whose output end is connected to the pressure head, is used to amplify the amplitude; and

[0016] A support structure is provided at the vibration node of the amplitude transformer to fix the ultrasonic vibration module to the main shaft clamp.

[0017] Furthermore, the amplification factor of the amplitude transformer is 4 to 8 times, and the amplitude range transmitted to the tip of the pressure head after being amplified by the amplitude transformer is 2 to 5 μm.

[0018] Furthermore, the laser-assisted heating module includes:

[0019] Laser;

[0020] A position adjustment mechanism, including a slide rail and a slider, is used to adjust the spatial position of the laser;

[0021] An angle adjustment mechanism includes a rotation axis passing through the laser for adjusting the incident angle of the laser beam; and

[0022] An optical focusing system is disposed in the output optical path of the laser and is used to focus the laser beam onto the surface of the workpiece.

[0023] Furthermore, the incident path of the laser beam is configured as one of the following:

[0024] The pressure is incident obliquely onto the contact area between the tip of the pressure head and the workpiece, relative to the workpiece surface; or

[0025] When the pressure head is made of transparent diamond, the laser beam passes perpendicularly through the body of the pressure head and irradiates the surface of the workpiece.

[0026] Furthermore, the electric field application module includes:

[0027] The base is fixed to the operating table;

[0028] The electrodes are configured as a pair, located on opposite sides of the workpiece;

[0029] An insulating block is disposed between the base and the electrode;

[0030] The electrode is electrically connected to a pulse power supply, which is configured to output a continuously adjustable current with a pulse frequency between 100Hz and 1000Hz.

[0031] Furthermore, the electrical insulation system includes:

[0032] A first insulating block is disposed between the tightening screw used for laterally locking the workpiece and the workpiece; and

[0033] The second insulating block is disposed between the inner wall of the clamp housing of the workpiece fixture and the workpiece.

[0034] On the other hand, the present invention proposes a multi-field assisted nanoindentation test method based on the above-mentioned device, comprising the following steps:

[0035] Positioning: The pressure head is moved to the predetermined indentation position on the workpiece surface by the three-axis moving mechanism;

[0036] Energy field loading: The ultrasonic vibration module is activated to apply high-frequency vibration to the pressure head, the laser-assisted heating module is activated to locally heat the contact area, and the electric field application module is activated to build a pulsed electric field within the workpiece;

[0037] Indentation execution: Under the environment of synchronous coupling of ultrasonic vibration, laser heating and pulsed electric field, according to the different stages of indentation head pressing, holding and unloading, the output parameters of at least one of the ultrasonic vibration module, the laser-assisted heating module and the electric field application module are dynamically adjusted to control the indenter to perform pressing, holding and unloading operations on the workpiece.

[0038] Furthermore, the energy field loading step and the indentation execution step include dynamically adjusting the output parameters of each module according to the processing stage:

[0039] In the initial stage of contact between the pressure head and the workpiece, the ultrasonic vibration module is adjusted to output a lower power and the laser-assisted heating module is adjusted to output a higher power.

[0040] During the indentation forming stage, the output power of the ultrasonic vibration module is increased, and the electric field strength of the electric field application module is increased;

[0041] During the load-holding phase, the output power of the laser-assisted heating module is reduced while the output power of the ultrasonic vibration module is maintained.

[0042] During the unloading phase, the output power of the ultrasonic vibration module is gradually reduced, and the laser-assisted heating module and the electric field application module are turned off.

[0043] Furthermore, the dynamic adjustment includes:

[0044] In the initial stage of the pressure head contacting the workpiece, the ultrasonic vibration module outputs a first power and the laser-assisted heating module outputs a second power to locally soften the workpiece surface before pressing in, wherein the second power is higher than the first power.

[0045] During the indentation forming stage, the output power of the ultrasonic vibration module is increased from the first power to the third power, and the electric field strength of the electric field application module is increased to promote the plastic flow and dislocation movement of the material.

[0046] During the load holding phase, the output power of the laser-assisted heating module is reduced, while the output power of the ultrasonic vibration module is maintained at the third power to promote stress relaxation of the material under load holding conditions.

[0047] During the unloading phase, the output power of the ultrasonic vibration module is gradually reduced until it is turned off, and the laser-assisted heating module and the electric field application module are also turned off.

[0048] The beneficial effects of this invention are:

[0049] This invention integrates an ultrasonic vibration module, a laser-assisted heating module, and an electric field application module onto the same indentation processing platform. It simultaneously applies high-frequency ultrasonic vibration, localized laser heating, and a pulsed electric field within the microscopic contact area between the indenter tip and the workpiece, forming an in-situ synergistic effect of force, heat, and electricity. Specifically, the ultrasonic vibration module amplifies the high-frequency vibration generated by the ultrasonic transducer via an amplitude transformer and transmits it to the indenter along the indentation direction, generating alternating stress at the contact interface. This reduces frictional resistance between the indenter and the material through the ultrasonic friction-reducing effect, while simultaneously promoting dislocation movement within the material through the acousto-plastic effect. The laser-assisted heating module focuses a continuous-wave carbon dioxide laser beam onto the same contact area, utilizing the material's absorption of a specific wavelength to achieve rapid local heating, causing the hard and brittle material to transition from a brittle to a ductile state, reducing the tendency to fracture. The electric field application module introduces a pulsed current into the workpiece through paired electrodes, utilizing electron wind and Joule heating effects to synergistically promote dislocation disengagement and slippage, further reducing deformation resistance. It simultaneously solves the dual challenges of high load and high risk of crack initiation in the processing of hard and brittle materials at the micro-nano scale. Its comprehensive effect cannot be achieved by simply superimposing the effects of individual energy fields.

[0050] In the ultrasonic vibration module, the clamping structure is positioned at the vibration node of the amplitude transformer. Since the node amplitude is zero, applying a fixed constraint at this point minimizes vibration energy dissipation, ensuring efficient axial transmission of the transducer's output energy to the indenter tip and maintaining amplitude stability. The laser-assisted heating module achieves position adjustment via a sliding rail and slider, and angle adjustment via a rotating shaft, ensuring the laser beam spot always precisely follows the indenter-workpiece contact area. Furthermore, when using a translucent diamond indenter, the laser can perpendicularly penetrate the indenter body to irradiate the workpiece surface, using the indenter itself as a light guide to transfer heat... The affected area is limited to directly below the pressing point, improving the spatial accuracy of heat input. In the electric field application module, electrodes are arranged in pairs on both sides of the workpiece and isolated from the base by insulating blocks. Together with the first insulating block between the tightening screw and the workpiece, and the second insulating block between the inner wall of the fixture housing and the workpiece, they form an electrical insulation system that confines the pulsed electric field to the internal processing area of ​​the workpiece, cuts off the leakage path of current through the fixture and base, avoids stray current interference to precision components such as force sensors, and ensures that the pulsed current density is concentrated in the processing area, so as to obtain sufficient electroplastic effect with low energy consumption.

[0051] In the initial contact phase, a lower ultrasonic power combined with a higher laser power preheats and softens the surface, allowing the indenter to be smoothly pressed in without slippage. During the forming phase, the ultrasonic power and electric field strength are simultaneously increased; both promote dislocation motion and plastic flow, reduce deformation resistance, and inhibit radial crack initiation. In the load-bearing phase, the laser power is reduced to avoid prolonged high temperatures that could lead to material phase transformation or burn-off, while maintaining a higher ultrasonic power to accelerate stress relaxation and creep deformation. In the unloading phase, the ultrasonic power is gradually reduced and the laser and electric field are turned off, allowing the material's elastic recovery process to proceed smoothly and preventing spalling or breakage caused by transient stress from the sudden removal of the energy field. This ensures that the force output of each energy field throughout the indentation process matches the instantaneous needs of the material, maintaining the integrity of the indentation shape while improving the accuracy of mechanical parameters such as hardness and elastic modulus extracted from the indentation data.

[0052] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram of the structure of the present invention in its working state.

[0055] Figure 2 This is a schematic diagram of the main shaft ultrasonic vibration module.

[0056] Figure 3 This is a schematic diagram of the electric field auxiliary module structure on the fixture.

[0057] Figure 4 This is a schematic diagram of the clamp and electrical insulation structure.

[0058] Figure 5 This is a schematic diagram of a laser heating structure.

[0059] In the diagram: 1. Base, 2. Spindle moving base, 3. Spindle, 4. Laser, 5. Electric field module, 6. Operating table, 7. Workpiece, 8. Tightening screw, 9. First guide rail, 10. Spindle clamp, 11. Clamp housing, 12. Slide rail, 13. Knob, 14. Second guide rail, 15. Lead screw, 31. Ultrasonic vibration transducer, 32. Holding structure, 33. Amplitude rod, 34. Pressure head, 51. Base, 52. Insulating block, 53. Electrode, 54. Opening, 81. First insulating block, 1101. Second insulating block, 1201. Laser module base, 1202. Slider. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] Example 1

[0063] Please see Figures 1 to 5 This embodiment provides a multi-energy field assisted nano-indentation processing device. The device includes a base 1, an operating table 6, a spindle moving base 2, a spindle clamp 10, an ultrasonic vibration module, a laser-assisted heating module, an electric field application module, and a workpiece clamp.

[0064] The operating table 6 is connected to the base 1 via the first guide rail 9 and can move along the first guide rail 9 in the Y direction. The spindle moving base 2 is connected to the base 1 via the second guide rail 14 and can move along the second guide rail 14 in the X direction. The spindle clamp 10 is mounted on the spindle moving base 2 and connected to the spindle moving base 2 via the lead screw 15, and can move up and down in the Z direction. The drive end of the lead screw 15 is connected to a knob 13, which is connected to a motor via a coupling to achieve precise movement in the Z direction. Through the above-mentioned X, Y, and Z three-axis moving mechanism, the precise positioning and adjustment of the relative position between the pressure head 34 and the workpiece 7 can be achieved. In this embodiment, the first guide rail 9 and the second guide rail 14 are both linear guide rails, and the lead screw 15 is a sliding lead screw.

[0065] Please refer to this carefully. Figure 2 An ultrasonic vibration module is mounted on the spindle clamp 10 and is used to apply high-frequency axial vibration parallel to the pressing direction to the pressure head 34. In this embodiment, the ultrasonic vibration module includes an ultrasonic vibration transducer 31, an amplitude transformer 33, a pressure head 34, and a clamping structure 32. The ultrasonic vibration transducer 31 is used to convert electrical signals into high-frequency mechanical vibration. The input end of the amplitude transformer 33 is connected to the output end of the ultrasonic vibration transducer 31, and the output end of the amplitude transformer 33 is connected to the pressure head 34, used to amplify the amplitude generated by the ultrasonic vibration transducer 31 and transmit the amplified vibration to the pressure head 34. The pressure head 34 is a diamond pressure head and is fixed to the output end of the amplitude transformer 33 by a threaded connection. The clamping structure 32 is disposed on the outer periphery of the amplitude transformer 33 and located at the vibration node position of the amplitude transformer 33, used to fix the entire ultrasonic vibration module on the spindle clamp 10 to minimize the dissipation of vibration energy to the spindle clamp 10. The vibration direction generated by the ultrasonic vibration module is axial, that is, parallel to the pressing direction of the pressure head.

[0066] Please refer to this carefully. Figure 5 A laser-assisted heating module is installed on the operating table 6 and is used to locally heat the predetermined processing position of the workpiece 7. In this embodiment, the laser-assisted heating module includes a laser 4, a slide rail 12, a slider 1202, a rotating shaft, a first locking mechanism, a second locking mechanism, and a laser module base 1201. The laser 4 is used to emit a laser beam, preferably a continuous wave carbon dioxide laser. The slide rail 12 is fixedly connected to the operating table 6 through the laser module base 1201. Specifically, the base 1201 is connected to the operating table 6 by side bolts. The slider 1202 slides in conjunction with the slide rail 12 to adjust the position of the laser 4 in the horizontal or vertical direction. The rotating shaft passes through the laser 4 and is installed on the slider 1202, allowing the laser 4 to rotate around the rotating shaft to adjust the irradiation angle of the laser beam. The first locking mechanism is provided on the slider 1202 to lock the slider 1202 at a predetermined position on the slide rail 12; the second locking mechanism is used to fix the laser 4 at a predetermined angle. The laser-assisted heating module also includes an optical focusing system disposed on the output optical path of the laser 4, which is used to focus the laser beam onto the surface of the workpiece 7.

[0067] In this embodiment, the incident path of the laser beam can be configured according to the material properties of the pressure head 34. One configuration is to set the optical path of the optical focusing system to be obliquely incident on the contact area between the tip of the pressure head 34 and the workpiece 7. Another configuration is that when the pressure head 34 is made of a translucent diamond material, the laser beam emitted by the laser 4 can pass perpendicularly through the body of the pressure head 34 and irradiate the surface of the workpiece 7. It should be understood that the above two optical path configurations can be selected and used according to actual processing requirements.

[0068] Please refer to this carefully. Figure 3 and Figure 4An electric field application module is mounted on the operating table 6 and contacts the workpiece 7 to create a pulsed electric field environment in the processing area. In this embodiment, the electric field application module includes a base 51, at least two electrodes 53, an insulating block 52, and an opening 54 formed in the base 51. The base 51 is fixed to the operating table 6 by bolts. Preferably, there are two electrodes 53, respectively located on opposite sides (e.g., front and rear sides) of the workpiece 7. One electrode is connected to the positive terminal of a power supply, and the other electrode is connected to the negative terminal, forming an electric field loop inside the workpiece 7. The electrodes 53 are made of conductive metal materials, including but not limited to copper, aluminum, stainless steel, or conductive alloys. The insulating block 52 is disposed between the base 51 and the electrodes 53 to achieve electrical insulation between the electrodes 53 and the base 51. The insulating block 52 is preferably made of epoxy resin insulating material. The opening 54 is formed on the side or bottom surface of the base 51 for power lines to pass through to connect the electrodes 53 to an external power source. The layout of the opening 54 avoids the processing area directly above the workpiece 7 to prevent interference with the processing process. In this embodiment, the external power supply is a pulse power supply, which is used to apply a pulse electric field to the workpiece 7.

[0069] Please continue reading. Figure 4 A workpiece fixture is mounted on the operating table 6 for clamping the workpiece 7. In this embodiment, the workpiece fixture includes a fixture housing 11 and a plurality of tightening screws 8. The fixture housing 11 is mounted on the operating table 6. The plurality of tightening screws 8 are distributed circumferentially along the workpiece 7 for laterally locking the workpiece 7. Preferably, there are eight tightening screws 8, which are symmetrically distributed along the X and Y directions of the workpiece 7 to uniformly lock the workpiece 7 in the horizontal plane.

[0070] To achieve electrical isolation between the workpiece 7 and other metal components of the device, this device is equipped with an electrical insulation system. This electrical insulation system includes a first insulating block 81, a second insulating block 1101, and the aforementioned insulating block 52 (which can be referred to as the third insulating block) disposed in the electric field application module. Specifically, the first insulating block 81 is disposed at the contact end between each tightening screw 8 and the workpiece 7, for achieving electrical insulation between the tightening screw 8 and the workpiece 7. The second insulating block 1101 is disposed on the inner wall of the fixture housing 11 and contacts or supports the workpiece 7, for achieving electrical insulation between the workpiece 7 and the fixture housing 11. In this embodiment, the first insulating block 81 is bonded and fixed to the end of the tightening screw 8 with industrial adhesive, and the second insulating block 1101 is bonded and fixed to the inner wall of the fixture housing 11 with industrial adhesive. Both the first insulating block 81 and the second insulating block 1101 are made of epoxy resin insulating material. The workpiece 7 is placed on the second insulating block 1101 and contacts the first insulating block 81, thereby maintaining electrical insulation between the workpiece 7 and the fixture housing 11 and the tightening screw 8. The first insulating block 81, the second insulating block 1101, and the third insulating block 52 together constitute an electrical insulation system, ensuring that the pulsed electric field only acts inside the workpiece 7 and does not leak through the fixture or base.

[0071] In this embodiment, the device first positions the indenter 34 to a predetermined processing position on the surface of the workpiece 7 via an X, Y, and Z three-axis moving mechanism. Then, depending on research or processing requirements, one or more of the ultrasonic vibration module, laser-assisted heating module, and electric field application module are selectively activated. When the ultrasonic vibration module is activated, the indenter 34 generates high-frequency axial vibration; when the laser-assisted heating module is activated, the laser beam is precisely aligned with the contact area between the tip of the indenter 34 and the workpiece 7 by adjusting the slide rail 12 and the rotating shaft, locally heating that area; when the electric field application module is activated, a pulsed electric field is applied to the interior of the workpiece 7 through the electrode 53. Under the combined action of a single energy field or multiple energy fields, the indenter 34 performs indentation, holding, and unloading operations on the workpiece 7, completing nano-indentation processing and mechanical property testing.

[0072] Example 2

[0073] This embodiment, based on the device structure described in Embodiment 1, further provides preferred operating parameters for each module and a multi-module collaborative operating mode. It should be understood that the following parameter ranges and operating modes are merely preferred embodiments of the present invention and are not intended to limit the invention.

[0074] The ultrasonic vibration module, laser-assisted heating module, and electric field application module can be turned on or off independently. In actual use, the single module can work or the multiple modules can work together, depending on the research purpose.

[0075] Single-module working mode: When it is necessary to study the effect of a single energy field on the nanoindentation process, one module can be turned on and the other two modules can be turned off. For example, by turning off the laser-assisted heating module and the electric field application module and turning on only the ultrasonic vibration module, the individual effect of ultrasonic vibration on the nanoindentation behavior of the material can be studied; similarly, a laser heating single-module working mode or an electric field single-module working mode can be implemented separately.

[0076] Dual-module collaborative working mode: When studying the coupling effect of two energy fields, two modules can be activated simultaneously while the third module is deactivated. For example, ultrasound-laser collaborative mode, ultrasound-electric field collaborative mode, or laser-electric field collaborative mode can be implemented separately.

[0077] Three-module collaborative working mode: When studying the comprehensive coupling effect of three energy fields, the ultrasonic vibration module, laser-assisted heating module, and electric field application module are activated simultaneously to achieve synergistic effects of multiple fields including heat, force, and electricity. This mode is the optimal working mode of this invention and is particularly suitable for high-quality nanoindentation processing and testing of hard, brittle, and difficult-to-machine materials.

[0078] In some preferred embodiments of this invention, the ultrasonic vibration transducer 31 operates at a frequency range of 20–50 kHz and has an input power range of 5–100 W. The amplitude range of the tip of the indenter 34, amplified by the amplitude transformer 33, is 2–5 μm, and the amplification factor of the amplitude transformer 33 is designed to be 4–8 times. The vibration direction generated by the ultrasonic vibration module is axial to maximize the efficiency of vibration energy transfer to the processing area and promote plastic flow of material in the indentation direction. Relevant parameters are summarized in Table 1.

[0079] Table 1 Optimal parameters for ultrasonic vibration module

[0080] Vibration frequency 20–50 kHz Input power 5～100 W Tip amplitude 2~5μm Amplitude of the variable rod 4 to 8 times

[0081] In some preferred embodiments of this invention, laser 4 is a continuous-wave carbon dioxide laser with a working distance (100mm) between the laser head and the tip of the pressure head, and an incident angle of 45° to effectively eliminate processing dead angles. The laser power is 150W-500W, and the maximum pulse energy is 15J. Relevant parameters are summarized in Table 2.

[0082] Table 2 Optimal parameters for laser-assisted heating module

[0083] laser power 150W-500W angle of incidence 45° working distance 100mm Maximum pulse energy 15J

[0084] In some preferred embodiments of this invention, an external power supply is a pulsed power supply used to apply a pulsed electric field to the workpiece 7. The pulse frequency is continuously adjustable between 100Hz and 1000Hz, the average pulse output current is 5A to 25A, and the pulse duration is 50μs to 200μs. The electrode 53 and the workpiece 7 are in surface contact to ensure a uniform distribution of the electric field within the processing area. Relevant parameters are summarized in Table 3.

[0085] Table 3 Optimal parameters for electric field application module

[0086] Pulse output average current 5A~25A pulse frequency 100 Hz~1000 Hz Pulse time 50μs~200μs

[0087] In this embodiment, a capacitive force sensor is used, with a force measurement resolution of 1 μN and a force measurement range of ±20 mN. The three-dimensional motion platform consists of three linear motion axes: X-axis, Y-axis, and Z-axis. The single-axis motion range is 10 mm, and the three-dimensional combined motion range is 10 mm × 10 mm × 10 mm, with a motion resolution of 1 nm. The spindle displacement system is used to control the precise insertion and withdrawal of the pressure head 34, with a spindle displacement range of 10 μm and a displacement resolution of 0.05 nm.

[0088] Example 3

[0089] This embodiment provides a multi-field assisted nanoindentation test method based on the above-mentioned device, including the following steps.

[0090] Positioning steps: The pressure head 34 is moved to the predetermined indentation position on the surface of the workpiece 7 by the three-axis moving mechanism.

[0091] Energy field loading steps: Activate the ultrasonic vibration module to apply high-frequency axial vibration to the pressure head 34, activate the laser-assisted heating module to locally heat the contact area between the tip of the pressure head 34 and the workpiece 7, and activate the electric field application module to build a pulsed electric field inside the workpiece 7.

[0092] Indentation execution steps: Under the environment where ultrasonic vibration, laser heating and pulsed electric field are synchronously coupled in the processing area, the pressure head 34 is controlled to perform pressing, holding and unloading operations on the workpiece 7.

[0093] In some preferred embodiments of this method, the method further includes dynamically adjusting the output parameters of each module according to the processing stage, so as to achieve optimized matching of each energy field at different processing stages, and further improve processing quality and efficiency. The specific dynamic adjustment strategy is as follows:

[0094] In the initial stage of contact between the pressure head and the workpiece (i.e., the initial processing stage), the ultrasonic vibration module is adjusted to output a lower power, the laser-assisted heating module is adjusted to output a higher power, and the electric field application module is adjusted to output a medium-intensity electric field in order to quickly soften the surface material of the workpiece 7.

[0095] During the indentation forming stage (i.e., during the indenter insertion process), the output power of the ultrasonic vibration module is increased from a lower power to a higher power, the output power of the laser-assisted heating module is maintained, and the electric field strength of the electric field application module is increased to a higher level to promote plastic flow of materials and dislocation movement.

[0096] During the load holding phase (i.e. when the indenter maintains the maximum indentation depth), the output power of the laser-assisted heating module is reduced, while the output power of the ultrasonic vibration module is maintained at a high level. At the same time, the electric field parameters of the electric field application module are kept constant to avoid overheating of the material and maintain the softened state of the material.

[0097] During the unloading phase (i.e., the process of the pressure head retracting), the output power of the ultrasonic vibration module is gradually reduced until it is turned off. At the same time, the laser-assisted heating module is turned off, and the electric field strength of the electric field application module is gradually reduced until it is turned off, in order to reduce the residual stress in the processing area.

[0098] It should be understood that the terms "lower power," "higher power," and "medium intensity" mentioned in the above dynamic adjustment strategy are relative values ​​within the operating parameter range of each module of the device. Those skilled in the art can make appropriate selections and adjustments based on the actual processing materials and process requirements.

[0099] In summary, this invention proposes a multi-energy field assisted nanoindentation processing device and its testing method, comprising a base, a three-axis moving mechanism, a spindle fixture, an ultrasonic vibration module, a laser-assisted heating module, an electric field application module, and an electrical insulation system. The ultrasonic vibration module transmits high-frequency vibration along the indentation direction to the tip of the indenter via an amplitude transformer; the laser-assisted heating module focuses a laser beam onto the contact area between the indenter and the workpiece for localized heating; the electric field application module applies a pulsed electric field to the workpiece through paired electrodes; and the electrical insulation system confines the electric field to the processing area within the workpiece. During processing, the three energy fields are synchronously coupled in the microscopic contact area between the indenter and the workpiece, and the ultrasonic power, laser power, and electric field intensity are dynamically adjusted according to the initial contact stage, indentation formation, load holding, and unloading stages, forming a synergistic mechanism of "friction reduction-thermal softening-plasticization promotion." This effectively reduces the processing load, inhibits crack propagation, and improves the surface quality and mechanical parameter testing accuracy of nanoindentation processing on hard and brittle materials.

[0100] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A multi-energy field assisted nano-indentation processing device, comprising a base (1), a workpiece fixture disposed on an operating table (6), and a three-axis moving mechanism for driving the spindle fixture (10) and the operating table (6) to move relative to each other in the X, Y, and Z directions, characterized in that, The device further includes: An ultrasonic vibration module is mounted on the spindle clamp (10). The output end of the ultrasonic vibration module is equipped with a pressure head (34). The ultrasonic vibration module is used to apply high-frequency vibration parallel to the pressing direction to the pressure head (34). A laser-assisted heating module is installed on the operating table (6). The output light path of the laser-assisted heating module is configured to align with the contact area between the tip of the pressure head (34) and the workpiece (7) for local heating of the area. An electric field application module includes an electrode (53) disposed on the operating table (6) and in electrical contact with the workpiece (7) for constructing a pulsed electric field in the processing area; And an electrical insulation system for electrically isolating the workpiece (7) from the base (1) and the metal parts of the workpiece clamp; The ultrasonic vibration module, the laser-assisted heating module, and the electric field application module are configured to simultaneously apply high-frequency vibration, local heating, and pulsed electric field to the contact area between the tip of the pressure head (34) and the workpiece (7) to form a force-heat-electric multi-energy field in-situ synergistic effect in the contact area.

2. The multi-field assisted nanoindentation processing device as described in claim 1, characterized in that, The ultrasonic vibration module includes: Ultrasonic vibration transducer (31); An amplitude transformer (33), whose input end is connected to the output end of the ultrasonic vibration transducer (31) and whose output end is connected to the pressure head (34), is used to amplify the amplitude; and A clamping structure (32) is provided at the vibration node of the amplitude rod (33) to fix the ultrasonic vibration module to the main shaft clamp (10).

3. The multi-field assisted nanoindentation processing device as described in claim 2, characterized in that, The amplification factor of the amplitude transformer (33) is 4 to 8 times, and the amplitude range transmitted to the tip of the pressure head (34) after being amplified by the amplitude transformer (33) is 2 to 5 μm.

4. The multi-field assisted nanoindentation processing device as described in claim 1, characterized in that, The laser-assisted heating module includes: Laser (4); The position adjustment mechanism includes a slide rail (12) and a slider (1202) for adjusting the spatial position of the laser (4); An angle adjustment mechanism includes a rotation shaft passing through the laser (4) for adjusting the incident angle of the laser beam; and An optical focusing system is provided on the light output path of the laser (4) to focus the laser beam onto the surface of the workpiece (7).

5. The multi-field assisted nanoindentation processing device as described in claim 4, characterized in that, The incident path of the laser beam is configured as one of the following: The pressure head (34) is obliquely incident on the surface of the workpiece (7) to the contact area between the tip of the pressure head (34) and the workpiece (7); or When the pressure head (34) is made of light-transmitting diamond, the laser beam passes perpendicularly through the body of the pressure head (34) and irradiates the surface of the workpiece (7).

6. The multi-field assisted nanoindentation processing device as described in claim 1, characterized in that, The electric field application module includes: The base (51) is fixed on the operating table (6); The electrodes (53) are configured as a pair, located on opposite sides of the workpiece (7); An insulating block (52) is disposed between the base (51) and the electrode (53); The electrode (53) is electrically connected to a pulse power supply configured to output a continuously adjustable current with a pulse frequency between 100Hz and 1000Hz.

7. The multi-field assisted nanoindentation processing device as described in claim 1, characterized in that, The electrical insulation system includes: A first insulating block (81) is disposed between the tightening screw (8) for laterally locking the workpiece (7) and the workpiece (7); and The second insulating block (1101) is disposed between the inner wall of the clamp housing (11) of the workpiece fixture and the workpiece (7).

8. A multi-field assisted nanoindentation testing method based on the device according to any one of claims 1 to 7, characterized in that, Includes the following steps: Positioning: The pressure head (34) is moved to the predetermined indentation position on the surface of the workpiece (7) by means of the three-axis moving mechanism; Energy field loading: The ultrasonic vibration module is activated to apply high-frequency vibration to the pressure head (34), the laser-assisted heating module is activated to locally heat the contact area, and the electric field application module is activated to build a pulsed electric field in the workpiece (7); Indentation execution: Under the environment of synchronous coupling of ultrasonic vibration, laser heating and pulsed electric field, according to the different stages of indentation, holding and unloading, the output parameters of at least one of the ultrasonic vibration module, the laser-assisted heating module and the electric field application module are dynamically adjusted to control the indenter (34) to perform indentation, holding and unloading operations on the workpiece (7).

9. The test method as described in claim 8, characterized in that, The energy field loading step and the indentation execution step include dynamically adjusting the output parameters of each module according to the processing stage: In the initial stage of contact between the pressure head and the workpiece, the ultrasonic vibration module is adjusted to output a lower power and the laser-assisted heating module is adjusted to output a higher power. During the indentation forming stage, the output power of the ultrasonic vibration module is increased, and the electric field strength of the electric field application module is increased; During the load-carrying phase, the output power of the laser-assisted heating module is reduced while the output power of the ultrasonic vibration module is maintained. During the unloading phase, the output power of the ultrasonic vibration module is gradually reduced, and the laser-assisted heating module and the electric field application module are turned off.

10. The test method as described in claim 9, characterized in that, The dynamic adjustment includes: In the initial stage of the pressure head contacting the workpiece, the ultrasonic vibration module outputs a first power and the laser-assisted heating module outputs a second power to locally soften the surface of the workpiece (7) before pressing in, wherein the second power is higher than the first power; During the indentation forming stage, the output power of the ultrasonic vibration module is increased from the first power to the third power, and the electric field strength of the electric field application module is increased to promote the plastic flow and dislocation movement of the material. During the load holding phase, the output power of the laser-assisted heating module is reduced, while the output power of the ultrasonic vibration module is maintained at the third power to promote stress relaxation of the material under load holding conditions. During the unloading phase, the output power of the ultrasonic vibration module is gradually reduced until it is turned off, and the laser-assisted heating module and the electric field application module are also turned off.

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