Influence of Ferroelastic Phase Transitions on the Spatial Distribution of Point Defects in Real Solids

Abstract

The crystallographic sites available for the point defects in the unit cells of the Ti-Ni, Au-Cd, Heusler alloys and vanadium crystals have been considered. Two different effects have been analyzed: i) spatial redistribution of point defects during the ferroelastic phase transitions (such as martensitic transformations in the Ti-Ni, Au-Cd and Heusler alloys); ii) deformation of crystal lattice caused by the hydrogen ordering in the course of hydrogen absorption in vanadium. The configurational order parameters describing the spatial symmetry of defect or hydrogen system have been constructed from the probabilities of crystallographic sites occupation by the defects or hydrogen atoms, respectively.