ALGEBRA AND GEOMETRY OF MARTENSITIC TRANSFORMATIONS IN THE IRON-ALLOYS

The martensitic transformation is a special form of phase transformati on that is not associated with the conventional temperature-dependent parameters: the number of centers and the crystal growth rate. The int ernal stresses are important for this transformation. How can we defin e the martensitic transformation? Possibly as follows: ''The martensit ic transformation is a diffusionless phase transformation that is indu ced by the stresses.'' The stream of studies devoted to the martensiti c transformation is not abating, and each author often has his own poi nt of view. But they all contribute very little to clarification of th e nature of this phenomenon and, unfortunately, even less to their use in practice; for example, for regulation of the kinetics of the trans formation. We shall present two articles that are devoted to the profo und causes and subtle characteristics of the martensitic transformatio n.