Martensite transformations: History and laws

Abstract

The results of research in the field of martensite transformations reflect the complexity and inexhaustible nature of this many-sided process, which shows the importance and expediency of continuation of the work in this field with the aim of finding new, still unknown possibilities for varying this process and discovering new aspects of its practical use. Concluding the review, I would like to list some fundamental notions formulated in the theoretical work ofG. V. Kurdyumov andA. L. Roitburd “On the nature of martensite transformations” [92], that reflect the large role of the martensite problem in the general theory of phase transformations: “The martensite problem is a cornerstone of the general problem of the structure and properties of crystalline bodies… The formation of substructure in martensite tranformation is a result of relaxation of stresses and a decrease in the elastic energy. This occurs with “pumping” of the elastic energy into the energy of interphase boundaries… There are grounds to assume that isothermal transformation occurs with formation of a more relaxed phase… This is proved indirectly by calorimetric measurements of the stored energy, which turns out to be substantially lower in an isothermal transformation than in an adiathermal one [157]… The main features of martensite kinetics consist in manifestation of the transformation proper rather than reflection of the specific features of the prepared centers of heterogeneous nucleation,”… they are “connected with inherent features of the transformation and, are not brought from outside together with the prepared center.”… “The significance of lattice defects in martensite transformations is similar to the role of impurities in crystallization of liquids. They affect the kinetic parameters substantially but do not change the general laws. In conclusion it should be stressed that many characteristics of martensite transformations are typical of all phase transformations. This is one of the causes of the long-term and fundamental nature of the problem.”