Dynamic Model of the Formation of Twinned Martensite Crystals: I. Control Wave Process and the Removal of Degeneracy in Twin-Boundary Orientation

摘要

In terms of the concept of the control wave process, it is proposed to consider the formation of internally twinned martensite crystals as a result of a consistent action of quasi-longitudinal waves, which determine the orientation of the habit plane, and of shorter longitudinal waves, which make the major con-tribution to the control of the growth of the main component of the twin structure. A simple set of equations corresponding to the propagation of a threshold deformation that leads to the formation of platelike regions is given. It is shown that the removal of the degeneracy with respect to the orientations of the expected twin boundaries is due to the existence of feedbacks upon the initiation of the Bain-deformation mechanism. It is noted also that the twin structure can be formed through the excitation of short-wavelength cells in the inter-phase region at the stage of the martensite-crystal growth.