Dresden 2006 – scientific programme
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MM: Metall- und Materialphysik
MM 44: Mechanical Properties II
MM 44.4: Talk
Friday, March 31, 2006, 11:45–12:00, IFW A
Correlation between acoustic and electromagnetic emissions in plastically deformed LiF — •Konstantin Chishko1, Tatiana Antsygina1, Claire Mavromatou2, and Vassilios Hadjicontis2 — 1B.Verkin Institute for Low Temperature Physics and Engineering, 47 Lenin Ave., Kharkov 61103, Ukraine — 2University of Athens, Panepistimiopolis, Zografos, TK 157 84, Athens, Greece
The experiments on plastic deformation (PD) of compressing LiF ionic monocrystals are performed with simultaneously registration of the acoustic emission (AE) and electromagnetic field (EF) near the sample surface measured with piezoelectric transducer and monopole coaxiale antenna, respectively. It has been found that jump-like deformation observed on promoted (rather late) stages of work hardening is accompanied by exclusive powerful AE bursts which can be associated with the break-through and emergence on the crystal free surface of large dislocation pile-ups formed due to evolution and intersection of different slip systems. Most of the acoustical events of such kind are accompanied by the measurable electromagnetic pulse whose appearance is strongly correlated with the front of the corresponding AE burst. The obtained phenomenon is obviously connected with the ionic lattice charge re-distribution controlled by interaction between dynamic dislocations and charged vacancies of the ionic crystal. The theory is proposed to interpret the electromagnetic emission during PD of an ionic crystal and the shape of EF pulse generated by a dynamical dislocation pile-up releasing from vacancy atmosphere is calculated. The theory predictions are in good agreement with the experimental observations.