Mechanism of the fcc-bcc martensitic transformation with the fastest transformation of close-packed planes. I. the lattice parameter ratio and habitus planes

In terms of the concepts of heterogeneous nucleation and the related driving wave process, a version of the dynamic theory of the formation of martensite crystals is stated in which the wave process initiates the fastest transformation of close-packed {111}γ atomic planes of a parent fcc phase into {111}α planes of a bcc phase. The lattice parameter ratio and the orientations of habit planes are analytically related with the elastic properties of the γ-phase. Quantitative estimation performed with the use of elastic moduli for an iron-nickel alloy yields habitus orientations close to {10 3 7}γ. An experiment is proposed to verify the theoretical predictions. A new pattern of the short-wave correction that finishes the fcc-bcc rearrangement is set forth. © 2008 Springer Science+Business Media, Inc