Acoustic Emission Characteristics of Metals

Abstract

This work was concerned with the study of the characteristics of the acoustic emission from various metals and with obtaining more information about this phenomena. Low and medium carbon steels, Aluminium, Copper and Brass were used in this work. Notched and unnotched flat and round tensile specimens of different dimensions were used. Three-point bending tests were carried out on steel specimens with different notch root radii. The frequency bandwidth of the acoustic emission monitoring system used was 100-300KH2. The output signals were rYecorded on a magnetic tape recorder and an on-line minicomputer was used to analyse the recorded signals. The results showed that the number of acoustic emissions was affected by many factors such as type of metal, microstructure, the notch size, and specimen size. However, the frequency content of the acoustic emission signals was less affected by the above factors, but the frequency ranges of the analysed signals was found to be affected by the type of test carried out i.e. tensile or three-point bending test. The results showed that acoustic emission is a very useful technique in material research and a valuable method for non-destructive testing.