We have revealed an electron emission on the switching of extrinsic gadolinium molybdate ferroelectric-ferroelastic in electric field. Visualization of the electron flow allows directly watching of the domain structure dynamics: formation and growth of tapered domains and lateral movement of the 180° domain wall. We have found that the electron emission contributes substantially to the screening processes in the case of a crystal with free surface.

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Abstract. The role of dislocations and the dynamical mechanism controlling the structural reconstruction in the process of nucleation and wave growth of new phase unit crystals at martensitic transformations in metallic systems are discussed. It has been established that near some rectilinear dislocations with lines and Burgers's vectors typical for the original phase, there are areas where an elastically deformed state is characterized by package of particularities unambiguously corresponding to the well defuute morphological attribute set (habit, orientation relationship, macroshear) of the martensite crystal. The distinctiveness of these areas for martensite nucleation is caused by character of strains reducing the magnitude of interphase energetic barrier. The elastic model of the dislocation-based nucleation center of martensitic crystal, allowing to select the dislocations being the most probable for nucleation and to make a martensitic crystal with the morphological attribute specific collection corresponding to each a dislocation, has been proposed. Such dislocations for certain Fe-, Cu-and TiNi-based alloys are indicated. New results for titanium nickel are presented in more detail.

Within the framework of the concepts of heterogeneous nucleation and wave growth of martensite the refinement of a technique of account of wave normals NW to expected habits planes are carried out. The technique allows to connect orientations of NW with definite areas of nucleation of crystals in an elastic field of defects. The specific results are for system Cu-Zn. As separate rectilinear dislocations with lines [l 1 71 and dislocation loops basic elements of which are pieces of these lines are considered here as probable centers of nucleation. It is shown, that the spectrum of NW can be coordinated with experimentally observable space distribution 8f normals N, in a vicinity of a pole[2 11 121. The similar coordination opens additional opportunities to reconstruct a stage of martensle nucleation from morphological attributes and to transform a distribution of habits in the informative parameter.

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