Soliton models of dislocation and acoustic emission in metallic materials

In this paper the analysis of the dislocation models and
the possibilties of their appliacation to the description of the acoustic
emission (AE) sources, which are acting during plastic deformation of metallic
materials are presented. Especially the one-dimensional atomic Frenkel-Kontorova
model pf dislocation (model FK) has been discussed with particular reference to
its nonlinear properties which determine the movement of the dislocation kink
along the dislocation line as a solitary wave process. At the same time the
equivalence of the FK model with the string model of dislocation (S model) has
been demonstrated. In consequence, the FK model has been generalized by the
consideration of new terms of higher order responsible for the anharmonic
(nonlinear) interaction between the atoms (including also the second
coordination zone). A new class of nonlinear partial differential equations
(NLPD equations), which may play a role in the theory of lattice vibration of
the crystal with dislocation as well as in the theory of dislocations, has been
obtained. The results are discussed in the context of rich experimental data
(obtained at IMIM) which establish the correlations between the measured AE
parameters and the plastic deformation mechanisms as well as microstructure
evolution accurring in fcc single and polycrystals subjected to channel-die
compression, especially at the liquid nitrogen temperature.