Acoustic emission in martensitic transformations

Abstract

Acoustic emission originates during martensitic transformations from sudden local changes of the displacement field across the propagating interfaces. Acoustic emission reveals the jerky character of the dissipation of the elastic energy excess, which proves that the transition occurs through avalanches. In this paper we show that the analysis of acoustic emission within an appropriate framework is a very useful technique, which provides quantitative dynamical information complementary to that obtained from more standard techniques. In particular, we will show that the probability density function of amplitudes, energies and durations of the detected acoustic signals follows power-law distributions related to avalanche criticality. This is illustrated with examples for non-magnetic and magnetic shape-memory alloys under selected external conditions.