New phase nucleus appearance on a twin boundary, which is with an invaribe velocity or oscillating

The occurrence and dynamics of a nucleus of a new phase on a moving twin boundary are described. The phase diagram of a nucleus on a moving twin boundary is obtained. It is shown that the nucleus can arise on the moving twin boundary only if its velocity tl is smaller than a certain value The existence of two kinds of low-symmetry phase trails (unstable and metastable) is described. The friction force, resulting from a trail and acting on a twin boundary is shown to arise. It is of a viscous type in the case of an unstable trail, and of a “ dry " friction force type in the case of metastable trail. The oscillation of the twin boundary with the nucleus in the external periodic field, conjugated to the order parameter is described