Crystal geometry and phenomenological models of reconstructive phase transitions

Abstract

The basic concepts of the phenomenological theory of reconstructive phase transitions are presented. The nonlinear order parameter concept is introduced and the connection between the classical form of the Landau theory and a density wave approach to phase transitions is given. This new phenomenological approach is applied both to standard examples of reconstructive phase transformations (BCC-HCP, BCC-FCC, HCP-FCC, BCC-w) and to new problems like the formation of quasicrystals.

Key Words:

• Reconstructive transitions
• phenomenological theory.