Fizika Nizkikh Temperatur: Volume 44, Number 9 (September 2018), p. 1186-1195 ( to contents , go back )
The nature of acoustic emission during deformation processes in metallic materials
A.Yu. Vinogradov1,2 and D.L. Merson1
1Togliatti State University, 14 Belorusskaya Str., Togliatti, 445020, Russia
2Norwegian University of Science and Technology – NTNU, Richard Birkelandsvei 2B, N-7491 Trondheim – NOR
Received April 18, 2018, published online July 26, 2018
In the pioneering works by V. Natsik and his colleagues, published in the 1960s–1980s, the theoretical foundation of the method of acoustic emission (AE) was laid. The source functions corresponding to elementary dislocation mechanisms of plastic deformation and fracture were calculated based on continuum dislocation dynamics. The results remain up to date. Despite the existing experimental difficulties in verifying some of the basic formulations, these works clearly demonstrated the differences between potential sources of acoustic emission in materials. Based on these fundamental premises, statistical methods wereproposed recently for recognizing the AE mechanisms, utilizing spectral and cluster analysis of AE time series. This brief communication reviews theoretical models of AE sources, as well as some key experimental findings shedding light on the nature of the acoustic emission peak in the early stages of plastic deformation of metals. The methods for analyzing the AE signal and recognizing the AE sources are also discussed.
Key words: acoustic emission, elementary sources, deformation mechanisms, cluster analysis.