A method for non-destructive detection of material texture by laser ultrasonic

Abstract

The invention belongs to the field of non-destructive testing and relates to a method for non-destructive testing of material texture by laser ultrasonic. The steps of the method are as follows: measurement; imaging; correction; secondary imaging; the present invention proposes a method for non-contact and non-destructive rapid detection of material texture using laser ultrasound, which is beneficial to non-destructive detection of material micro texture. The change of the ultrasonic surface wave velocity excited by the laser measures the grain orientation distribution map to reflect the material texture. The sample is placed directly on the test bench, and the sample detection area is only limited by the movement range of the test bench. The detection area is flexible and the detectable range is large. Second, the laser spot used in the present invention can be adjusted, so that the single measurement range can be changed. Correspondingly, the measurement spatial resolution can be adjusted. In the case of low spatial resolution requirements, high detection efficiency can be obtained. Third, the surface of the sample can be polished without polishing, and has low requirements on the sample, which is especially suitable for large-scale scanning.

Description

technical field [0001] The invention relates to a method for non-destructive detection of material texture by laser ultrasonic, belonging to the field of non-destructive detection. Background technique [0002] The structure in which the polycrystalline orientation distribution state obviously deviates from the random distribution is called texture. Many materials require their texture to be detected in order to analyze and predict their performance. The grain orientation distribution diagram is the most intuitive way to characterize the material texture. Method, the method that can obtain grain orientation distribution map at present is mainly electron backscatter diffraction (EBSD) method, but, there are following three problems in this method: first, electron backscatter diffraction (EBSD) method is based on an annex of scanning electron microscope, The sample to be tested must be able to meet the requirements of scanning electron microscopy. The length, width and height ...

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Problems solved by technology

[0002] The structure in which the polycrystalline orientation distribution state obviously deviates from the random distribution is called texture. Many materials require their texture to be detected in order to analyze and predict their performance. The grain orientation distribution diagram is the most intuitive way to characterize the material texture. Method, the method that can obtain grain orientation distribution map at present is mainly electron backscatter diffraction (EBSD) method, but, there are following three problems in this method: first, electron backscatter diffraction (EBSD) method is based on an annex of scanning electron microscope, The sample to be tested must be able to meet the requirements of scanning electron microscopy. The length, width and height of the sample are difficult to exceed 50mm. For large-sized samples, it can only be detected by dividing it into small pieces. Secondly, this method uses a diameter of only a few Scanning with an electron beam of 10 microns, each measurement covers a small area. If a larger area needs to be scanned, it will take a long time for detection. Finally, this method generally requires the sample to be electrolytically polished, which takes a long time and is inefficient. In summary, existing methods are not suitable for scanning large-scale grain orientations of larger-grained materials