Acoustic emission mechanisms in Armco iron

Acoustic emission, measured as the r.m.s. of the amplitude, was obtained during deformation of Armco iron as a function of temperature and holding time, at a given temperature. It was found that the restoration of acoustic emission is a function of temperature and applied total strain. A mechanism of microplasticity and unpinning of mobile dislocations is used to explain these results. It is concluded that the Kaiser effect (the restoration of acoustic emission) is dependent on the above-mentioned variables.