Method for detecting Young's modulus of piezoelectric material surface by laser surface acoustic wave

Abstract

The invention discloses a method for detecting the Young's modulus of the surface layer of a piezoelectric material based on laser surface acoustic wave technology, comprising: using a pulse laser to excite high-frequency surface acoustic waves on the surface layer of a piezoelectric test piece, and picking up the acoustic surface with a propagation distance of 1 to 2 cm Wave signal processing, fitting the dispersion curve to obtain the phase velocity close to the true value; establishing a layered piezoelectric material model under ideal conditions, combining the wave equation of the surface acoustic wave in the piezoelectric medium and the electromagnetic wave equation to obtain the basic propagation equation of the surface wave; Combined with the piezoelectric medium boundary conditions, calculate the corresponding relationship between wave velocity and wave number; obtain the relationship between wave velocity, frequency and Young's modulus under ideal conditions, analyze and compare the experimentally fitted dispersion curves, and obtain the absolute Young's modulus of the tested piece , the minimum Young's modulus Ea and the maximum Young's modulus Eb. The invention can not only improve the reliability and anti-interference of the detection result, but also make the detection device change to miniaturization, confidentiality and the like, and promote the application of the technology in theoretical research and practical application.

Description

technical field [0001] The invention belongs to the field of material performance detection and specifically designs a method for detecting the Young's modulus of the surface layer of a piezoelectric material. Background technique [0002] Piezoelectric materials are materials that can convert electrical energy into mechanical energy. When an external force acts on the piezoelectric material and causes the material to deform, a discharge phenomenon occurs. Piezoelectric materials are widely used in thermo-optoacoustic electronics and other fields because of their unique properties, simple fabrication, low cost, and high energy conversion efficiency. With the development of high technology in this field, people have higher and higher requirements on the performance of piezoelectric materials. Generally, piezoelectric materials are very difficult to process. If there is a slight improper processing, the surface and sub-surface of the workpiece will be damaged to varying degr...

AI Technical Summary

Problems solved by technology

However, the measurement results of nanoindentation technology are easily affected by the internal and external conditions of the test piece, such as the creep and thermal drift of the internal piezoelectric device will greatly interfere with the results

When measuring thin film specimens at the same time, the measurement results will be greatly affected by the substrate material

In addition, methods such as dynamic mechanical spectrum analysis technology, Brillouin light scattering technology, and acoustic scanning microscopy are also used in the measurement of Young's modulus of piezoelectric materials, but due to inconvenient operation, large errors, expensive equipment, and lack of Applicability and other factors cannot be widely used

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