Acoustic emission induced by dislocation annihilation during plastic deformation of crystals

A description of the dislocation annihilation component of acoustic emission (AE) during plastic deformation of crystals is presented. The annihilation of dislocation kink–antikink pairs during Frank–Read source operation is investigated within the framework of a dynamic model describing the interaction between dislocations and acoustic waves. This model consists of a d’Alembert wave equation nonlinearly coupled to a sine-Gordon equation. The AE by annihilating dislocation kinks is considered and both the emitted energy and the power spectral density of the emitted waves are calculated. It is shown that the lifetime of the generating event is inversely proportional to the square of the applied stress in agreement with existing measurements. The stress corresponding to maximum emission is calculated and is found also to be in agreement with existing experimental data. The obtained results support the hypothesis that the annihilation of dislocations can also be a source of considerable AE during plastic deformation of crystals. The proposed model, furthermore, provides a better physical insight to the emission mechanisms involved.