Initial Excited State and Divergence of Wave Beams as Factors Responsible for the Realization of the Wave Process that Controls the Growth of Transformation Twins

Abstract

In the dynamic theory of martensitic transformations the wave mechanism of growth of martensite crystals is controlled by the overlap of wave beams of quasi-longitudinal (or longitudinal) waves that carry deformation of the “tension–compression” type in orthogonal directions. The appearance of wave beams is considered a consequence of the appearance of the initial excited (vibrational) states. The presence of the transformation twins is interpreted as the result of the matched propagation of relatively long-wave (???? waves) and short-wave (s waves) displacements. With the aid of the Fourier transforms, an analysis was performed of the influence of the diffraction divergence of a pair of orthogonal wave beams on the formation of a region of their superposition, including the limiting case of narrow beams with one of the transverse dimensions of the front less than λ/2, where λ is the wavelength. The connection of the distribution of the amplitudes of spatial harmonics with the configuration of the initial excited state is discussed.