Ultrasonic detection method for micro-nano cracks of metal material

Abstract

The invention belongs to the technical field of microscopic detection of metal materials, and particularly relates to an ultrasonic detection method for metal material micro-nano cracks, which comprises the following steps: each array element in an ultrasonic array simultaneously transmits an initial pulse signal to a target in a detection area of a to-be-detected metal material along a respective signal transmission channel; aiming at the target, a group of reflection signals formed by a plurality of linear frequency modulation signals are generated; each array element in the ultrasonic array receives a group of reflected signals reflected by the target; performing time reversal processing on the group of reflected signals based on a time reversal mirror method to obtain a group of time reversal signals; each array element in the ultrasonic array reversely transmits a corresponding group of time reversal signals to the target along the same signal transmission channel, and the peak value of the group of time reversal signals at the current moment is obtained; and obtaining the position coordinate of the target according to the peak value, thereby completing the detection of the micro-nano crack of the metal material.

Description

technical field [0001] The invention belongs to the technical field of microscopic detection of metal materials, and in particular relates to an ultrasonic detection method for micro-nano cracks of metal materials. Background technique [0002] Metal materials are widely used in many fields such as aerospace, military equipment and intelligent manufacturing. Microscopic defect detection of metal materials has always been a research hotspot. Under the application of cyclic load, metal materials will undergo cyclic slip and form extremely non-uniform cyclic slip bands. These cyclic slip bands are usually concentrated in some local weak areas. After a long period of cyclic stress, in these cycles The slip zone region is prone to microcrack initiation. The cracks started as small microscopic short cracks and gradually increased with the increase of loading times. Micro-cracks will lead to catastrophic failure of the material with little warning. The existence of micro-cracks p...

AI Technical Summary

Problems solved by technology

[0007] The ray detection method is more sensitive to volume defects, but not sensitive to area defects, and it is easy to miss or misdetect;

[0008] Penetrant testing methods cannot detect buried defects or closed surface defects;

[0009] Therefore, none of the existing detection methods can detect micro-nano cracks in metal materials, and the detection accuracy is low.

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