阅读说明：本技术 激光薄膜内耗仪及材料内耗的检测方法 (Laser film internal consumption instrument and material internal consumption detection method ) 是由 刘向兵 李远飞 薛飞 王春辉 徐超亮 钱王洁 贾文清 李心刚 池志远 安英辉 段 于 2019-09-26 设计创作，主要内容包括：本发明公开了一种激光薄膜内耗仪,包括激光位移传感器、底板、固定在所述底板上的下罩体以及与所述下罩体相配合的上罩体,所述底板、下罩体和上罩体之间形成腔体,所述腔体内设置有试样固定组件、激发电极、加热器以及屏蔽罩,所述下罩体上开设有与所述激光位移传感器对应的光学窗口,所述加热器位于所述屏蔽罩内,所述屏蔽罩用于罩住所述试样以及激发电极,所述屏蔽罩对应所述激光位移传感器开设有贯通孔,所述激发电极朝向所述贯通孔,所述试样位于所述贯通孔与激发电极之间。本发明的激光薄膜内耗仪,具有测量精度高、工作频率宽、非接触测量获得材料缺陷信息等优点,非常适合进行辐照缺陷的表征。(The invention discloses a laser film internal consumption instrument which comprises a laser displacement sensor, a bottom plate, a lower cover body fixed on the bottom plate and an upper cover body matched with the lower cover body, wherein a cavity is formed among the bottom plate, the lower cover body and the upper cover body, a sample fixing assembly, an excitation electrode, a heater and a shielding cover are arranged in the cavity, an optical window corresponding to the laser displacement sensor is arranged on the lower cover body, the heater is positioned in the shielding cover, the shielding cover is used for covering the sample and the excitation electrode, a through hole is formed in the shielding cover corresponding to the laser displacement sensor, the excitation electrode faces towards the through hole, and the sample is positioned between the through hole and the excitation electrode. The laser film internal friction instrument has the advantages of high measurement precision, wide working frequency, non-contact measurement for obtaining material defect information and the like, and is very suitable for representing irradiation defects.)

1. The utility model provides a consume appearance in laser film, its characterized in that includes laser displacement sensor, bottom plate, fixes lower cover body on the bottom plate and with cover body matched with last cover body down, form the cavity between bottom plate, lower cover body and the last cover body, be provided with the fixed subassembly of sample, arouse electrode, heater and shield cover in the cavity, set up on the lower cover body with the optical window that laser displacement sensor corresponds, the heater is located in the shield cover, the shield cover is used for covering sample and arouse the electrode, the shield cover corresponds laser displacement sensor has seted up the perforating hole, arouse the electrode orientation the perforating hole, the sample is located between perforating hole and the arouse electrode.

2. The laser thin film internal consumption instrument as claimed in claim 1, wherein an excitation electrode moving assembly is further disposed in the cavity, the excitation electrode moving assembly comprises a slider, a screw rod driving the slider to move, and a motor driving the screw rod to rotate, the excitation electrode is fixed on the slider through a fixing plate, and the motor is fixed on the bottom plate.

3. The laser thin film internal friction instrument according to claim 2, wherein a partition plate is arranged in the cavity, the partition plate is fixed on the bottom plate through a fixing column, the shielding cover is fixed on the partition plate, and a sliding groove for moving the fixing plate is formed in the partition plate.

4. the laser thin film internal friction instrument as claimed in claim 2, wherein an insulating ring is disposed between said excitation electrode and said fixing plate.

5. The laser thin film internal consumption instrument as claimed in claim 1, wherein the sample fixing assembly comprises a sample chuck, a supporting plate connected with the sample chuck and a lifting mechanism driving the supporting plate to move up and down, and the sample is fixed at the lower end of the sample chuck through a chuck screw.

6. the laser thin film internal consumption instrument as claimed in claim 1, wherein the heaters are uniformly distributed on the inner side of the shielding case, and the heaters extend along the axial direction of the shielding case.

7. The laser thin film internal consumption instrument as claimed in claim 1, further comprising a lifting assembly for driving the upper cover body and the lower cover body to separate or attach, and a vacuum pump set for evacuating the cavity.

8. The laser thin film internal friction instrument according to claim 7, wherein the bottom plate is further provided with a vacuum valve for connecting with the vacuum pump set; and the bottom plate is also provided with a damping component.

9. The laser thin film internal friction instrument as claimed in claim 1, wherein said laser displacement sensor is fixed on said base plate, and said laser displacement sensor, optical window, through hole and excitation electrode are located on the same axis.

10. A method for detecting the internal consumption of a material by a laser thin film internal consumption instrument according to claim 1, which comprises the following steps:

S1, opening a vacuum cavity: releasing the vacuum, starting the lifting assembly, pushing the upper cover body to move upwards, and opening the cavity;

S2, installing a sample: loosening a chuck screw, inserting one end of a sample to be tested into a gap of a sample chuck, and then screwing the chuck screw to clamp the sample;

S3, vibration test: applying bias voltage to the excitation electrode, controlling a laser beam of the laser displacement sensor to irradiate the surface of the sample, observing whether a vibration signal of the sample returns, and finishing the vibration test if the vibration signal exists; if no vibration signal exists, the position of the sample and the excitation electrode is determined until a vibration signal appears;

S4, closing the vacuum cavity: starting the lifting assembly, moving the upper cover body downwards until the upper cover body is attached to the lower cover body, sealing the cavity, opening the vacuum valve, starting the vacuum pump set, and vacuumizing;

S5, setting parameters: setting test parameters and starting a test program;

S6: and (3) testing: collecting vibration signals, calculating internal friction and elastic modulus values, obtaining results and analyzing the results;

S7: and (3) closing the system: and (5) stopping the test program after the test is finished, adjusting the bias power supply to zero, and closing the control system.

Technical Field

The invention particularly relates to a laser film internal friction tester for detecting material defects in a non-contact manner and a method for detecting by using the laser film internal friction tester.

Background

the internal friction testing technology is an advanced nondestructive testing technology, is sensitive to the microstructure of a metal material, and is applied to microstructure research of nuclear structural material irradiation defects and nondestructive testing of material aging. The measurement of internal consumption spectrum is distinguished from other nondestructive detection methods in that the frequency range completely covers the intrinsic frequency range of the defect slow transition process, the applied stimulation signal is alternating stress (the amplitude of the applied stimulation signal is far smaller than the yield stress of a material), the reaction signal is strain, the method is suitable for any object capable of transmitting elastic stress waves, and the method is proved to be one of the most effective means for researching the defect relaxation process and microstructure change.

The internal friction refers to the ability of the material to consume kinetic energy rapidly and slowly under the condition isolated from the outside, and its physical nature is the dissipation of mechanical vibration energy caused by internal defects and atomic motion of the material, so that the microscopic defect information of the material can be reflected by measuring the internal friction and the elastic modulus change of the material under certain external conditions (such as temperature, frequency, amplitude, etc.), and the microscopic defect parameters such as defect concentration and distribution, defect diffusion activation energy, phase change dynamics, etc. are obtained, therefore, the internal friction technology is also often called as internal friction spectrum or mechanical spectrum. The measuring frequency range of the internal consumption spectrum is 0.001Hz to kHz, the intrinsic frequency range of the process of defect slow transition (such as the transition process of point defects between adjacent equilibrium positions) is completely covered, the added stimulation signal is alternating stress (the amplitude of the alternating stress is far less than the yield stress of a material), and the reaction signal is strain, so the method is suitable for any object capable of transmitting elastic stress waves and is proved to be one of the most effective nondestructive detection means for researching the defect relaxation process and microstructure change.

Currently, the internal friction measurement method mainly adopts two modes of forced vibration and free damping. When internal consumption measurement is carried out in a forced vibration mode, a sine wave signal sigma generated by the ultralow frequency signal generator is sigma-sigma₀sin and omega t are amplified and sent to a driving coil to drive a swing rod attached with a permanent magnet to twist so as to enable the swing rod to perform torsional vibration according to a sine wave rule, and a strain signal can be expressed as epsilon ═ epsilon₀sin (ω t- φ) is compared with the excitation sine signal to obtain the phase angle difference φ of the two signals, and the corresponding tan φ is the internal loss value Q^-1。

In the free attenuation mode, the internal loss measurement principle is as follows: the computer gives a command to twist the sample to a set maximum amplitude, then the sample makes a free damping movement, and the vibration damping curve is measured. The value of δ can be calculated using the amplitudes of a plurality of vibrations under the condition that the internal loss is independent of the amplitude, i.e., the value of δ can be calculated using the relation (1). A. the_nAnd A_n+mAre respectively nand the amplitude of the (n + m) th vibration.

Thus, from the free decay curve of the sample, according to the internal consumptionThe internal consumption value of the sample can be obtained by the calculation formula (2).

The internal friction measuring technology does not leave two measuring modes of forced vibration and free damping, and the development of the current internal friction testing equipment mainly aims at meeting the requirements of samples with different properties and shapes and sizes. Relevant researchers at home and abroad continuously explore through long-term practice, and a series of internal consumption measuring technologies with both scientificity and practicability are developed at present. The method mainly comprises an electrostatic excitation vibration method, an optical microscopic amplification detection strain amplitude, an atomic force microscope cantilever beam detection strain amplitude and the like, and the following problems exist when the technology is used for detecting the irradiation damage surface defects of the nuclear power material: (1) the capacitive sensor has insufficient measurement accuracy. The laser displacement sensor sold in the market can not be used at high and low temperatures, or the amplitude of the sample is required to be as large as possible, so that the requirement of micro-amplitude detection can not be met. (2) Changing the measurement frequency is cumbersome. In order to improve the measurement accuracy, the thin film internal friction instrument adopts a cantilever beam sample clamping mode to force the sample to vibrate at a resonance frequency to realize maximum amplitude, but the variable frequency measurement needs to change the clamping length, which cannot be realized in the single variable temperature measurement. (3) The circuit design is complex. The weak vibration of a sample under the resonance frequency is measured, the circuit design adopts a high-frequency carrier to obtain a sample vibration capacitance change signal, the interference of various distributed capacitances to the high-frequency signal is required to be considered in the circuit design, and the stability and the operability of the circuit are also reduced. (4) The temperature-changing sample deforms, so that the stable operation cannot be realized. The sample is deformed due to the temperature rise in the test process, and the excitation electrode or the collection electrode is close to the far end of the sample, so that the excitation electrode or the collection electrode can be touched to cause that the measurement cannot be carried out. The existence of the problems can potentially influence the accuracy of the quantitative data of the internal consumption physical parameters.

disclosure of Invention

in view of the above, in order to overcome the defects of the prior art, the present invention aims to provide a laser thin film internal consumption instrument.

In order to achieve the purpose, the invention adopts the following technical scheme:

The utility model provides a laser film internal consumption appearance, includes laser displacement sensor, bottom plate, fixes lower cover body on the bottom plate and with cover body matched with last cover body down, form the cavity between bottom plate, lower cover body and the last cover body, be provided with the fixed subassembly of sample, arouse electrode, heater and shield cover in the cavity, set up on the lower cover body with the optical window that laser displacement sensor corresponds, the heater is located in the shield cover, the shield cover is used for covering sample and arouse the electrode, the shield cover corresponds laser displacement sensor has seted up the perforating hole, arouse the electrode orientation the perforating hole, the sample is located between perforating hole and the arouse electrode. The exciting electrode is used for driving the sample to vibrate, the sample is forced to vibrate under specific frequency by loading direct-current bias voltage and variable-frequency alternating voltage between the sample to be tested and the exciting electrode, a laser displacement sensor is used for collecting a sample vibration signal, and the waveform of the sample vibration is obtained, so that the parameters of the material such as damping, modulus and the like are obtained, and further the information of the material such as microscopic defects and the like is obtained.

Preferably, an excitation electrode moving assembly is further arranged in the cavity and comprises a sliding block, a lead screw and a motor, the lead screw is driven to move, the motor drives the lead screw to rotate, the excitation electrode is fixed on the sliding block through a fixing plate, and the motor is fixed on the bottom plate. The moving assembly drives the excitation electrode to move, so that the distance between the excitation electrode and the sample to be detected is adjusted.

more preferably, a partition board is arranged in the cavity and fixed on the bottom board through a fixing column, the shielding cover is fixed on the partition board, and a sliding groove for the fixed board to move is formed in the partition board. The exciting electrode moving assembly is positioned below the partition plate, and the shielding cover, the heater and the sample fixing assembly are positioned above the partition plate.

more preferably, an insulating ring is disposed between the excitation electrode and the fixing plate.

Preferably, the sample fixing assembly comprises a sample chuck, a support plate connected with the sample chuck and a lifting mechanism driving the support plate to move up and down, and the sample is fixed at the lower end of the sample chuck through a chuck screw. The lifting mechanism drives the supporting plate to move so as to drive the sample to be tested to move up and down, and the position of the sample to be tested is adjusted. In some embodiments, the sample chuck is further provided with a waist-round hole extending along the up-and-down direction of the sample chuck so as to adjust the position of the sample chuck fixed on the support plate.

Preferably, the heaters are uniformly distributed on the inner side of the shielding case, and the heaters extend along the axial direction of the shielding case. The heater is the bar-shaped, and it evenly distributed on the shield cover inner wall for it is more even to heat up, and for the irradiation heating, and rate of heating is fast. The shield is used to prevent heat from radiating out of the device. In some embodiments, the laser thin film internal consumption instrument can also be added with a water cooling system to control the temperature more accurately.

Preferably, the laser film internal friction instrument further comprises a lifting assembly for driving the upper cover body and the lower cover body to be separated or attached and a vacuum pump set for vacuumizing the cavity.

more preferably, the bottom plate is further provided with a vacuum valve for connecting with the vacuum pump set; and the bottom plate is also provided with a damping component. The shock absorbing assembly may be disposed under the base plate and may be disposed between the cover and the base plate.

Preferably, the laser displacement sensor is fixed on the bottom plate, and the laser displacement sensor, the optical window, the through hole and the excitation electrode are located on the same axis, so that a laser beam of the laser displacement sensor can strike a sample to be measured.

The sample to be tested is clamped and fixed in the vacuum cavity through the sample chuck, the excitation electrode is installed on the opposite side of the sample and used for driving the sample to vibrate, the heating system and the water cooling system surround the sample to provide high and low temperature environment, in order to prevent the influence of air damping on the high-frequency vibration amplitude and frequency of the sample, the vacuum machine set is used for extracting high vacuum from the vacuum cavity during testing, the whole vacuum cavity is isolated from the ground, and the interference of mechanical vibration is eliminated.

The invention also provides a detection method using the laser film internal friction instrument, which comprises the following steps:

S1, opening a vacuum cavity: releasing vacuum, and when the vacuum state in the cavity is changed into an atmospheric normal pressure state, starting the lifting assembly to push the upper cover body to move upwards and open the cavity;

S2, installing a sample: loosening a chuck screw, inserting one end of a sample to be tested into a chuck gap, then tightening the screw to clamp the sample, and adjusting the position of an excitation electrode;

S3, vibration test: applying bias voltage to the excitation electrode, controlling a laser beam of the laser displacement sensor to irradiate the surface of the sample, observing whether a vibration signal of the sample returns, and finishing the vibration test if the vibration signal exists; if no vibration signal exists, the position of the sample and the excitation electrode is determined until a vibration signal appears;

S4, closing the vacuum cavity: the lifting assembly moves the upper cover body downwards until the upper cover body is attached to the lower cover body, the cavity is closed, the vacuum valve is opened, the vacuum pump set is started to vacuumize, and the vacuum pump set is extracted 10^-2High vacuum of Pa and above;

S5, setting parameters: setting parameters such as test temperature, test time, excitation amplitude, excitation frequency and the like, and starting a measurement program;

S6: and (3) testing: collecting vibration excitation signals and vibration signals, displaying vibration waveforms, calculating internal consumption and elastic modulus values, obtaining results and analyzing the results;

S7: and (3) closing the system: and (5) stopping the test program after the test is finished, adjusting the bias power supply to zero, and closing the control system.

compared with the prior art, the invention has the advantages that: the laser film internal friction instrument has the advantages of high measurement precision, wide working frequency, non-contact measurement for obtaining material defect information and the like, and is very suitable for representing irradiation defects.

drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

FIG. 1 is a perspective view of a laser thin film internal friction gauge in a preferred embodiment of the present invention;

FIG. 2 is a partial perspective view of a laser thin film internal friction gauge in a preferred embodiment of the present invention;

FIG. 3 is a top view of FIG. 2;

3 FIG. 3 4 3 is 3 a 3 cross 3- 3 sectional 3 view 3 A 3- 3 A 3 of 3 FIG. 3 3 3; 3

FIG. 5 is a perspective view of the laser film inside wear gauge of FIG. 2 with the lower housing hidden;

FIG. 6 is a perspective view of the laser film inside wear gauge of FIG. 5 with the diaphragm hidden;

FIG. 7 is a perspective view of a shield and a heater in the laser thin film inside consumption meter;

FIG. 8 is a schematic view of a specimen undergoing bending under a force perpendicular to the specimen axis;

FIG. 9 is a schematic view of a specimen to be measured used in the calculation and analysis of Young's modulus in example 3;

FIG. 10 is a graph showing the results of Young's modulus and internal friction measurements of a stainless steel sheet of varying cross section in example 3;

In the drawings: the device comprises a laser displacement sensor-1, a bottom plate-2, a lower cover-3, an upper cover-4, an excitation electrode-5, a heater-6, a shielding cover-7, an optical window-8, a through hole-9, a top hole-10, a sample-11, a slide block-12, a screw rod-13, a motor-14, a partition plate-15, a fixed column-16, a chute-17, a fixed plate-18, a sample chuck-19, a support plate-20, a lifting mechanism-21, a chuck screw-22, a lifting assembly-23, a vacuum valve-24, a waist circular hole-25 and a frame-26.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not a whole embodiment. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.