Sadanov I. Field ion microscopy of atomic structure of boundaries and triple junctions of grains in metals and alloys

The dissertation is devoted to definition of atomic structure of boundaries and triple junctions of grains in metals and alloys by methods of high-resolution field ion microscopy. Grain boundaries and triple junctions of grains of special and random types are investigated at an atomic level. The changes of structural and energetic states of such boundaries and triple junctions of grains are revealed. It is shown, that grain boundaries of the random type at an atomic level are well structured and are characterized by existence of the subset of self-interstitial atoms. Existence of atoms in interstitial positions, in relation to the both contacting crystals, can be considered as a universal rout of the description of an atomic structure of grain boundaries of the random type. Noncoherent borders of twin boundaries are investigated and the existence of ensembles of grains, topologically bounded with special misorientations is revealed.