The study of phase transitions in Al–Cu–Fe alloys is of considerable interest due to their unique physical properties and complex crystal structure. In this paper, we investigate the mechanism of the phase transition between the quasicrystalline and microcrystalline states in the Al–Cu–Fe alloy using structural analysis methods.
The quasi-crystalline state, characterized by icosahedral symmetry, is metastable and under certain conditions can transform into a microcrystalline state with the formation of complex intermetallic phases. The modulated structure of the quasicrystal, arising due to deviations from the ideal icosahedral symmetry, plays an important role in the phase transition process. High-resolution transmission electron microscopy and X-ray diffraction methods allow a detailed study of the structural changes that occur during the phase transition. Analysis of diffraction patterns and high-resolution images reveals the presence of a domain structure and defects that initiate and control the crystallization process.
The obtained results indicate that the phase transition in Al–Cu–Fe is a complex multistage process, including the formation of microcrystalline phase nuclei, their growth and coalescence. The modulated structure of the quasicrystal has a significant effect on the kinetics of the phase transition and the morphology of the resulting microcrystalline phases.
Further study of the phase transition mechanism requires consideration of thermodynamic factors and diffusion processes. The atomic rearrangement required to form the microcrystalline structure includes the diffusion of aluminum, copper, and iron. The diffusion rate and its dependence on temperature determine the phase transition rate. Computer modeling using the molecular dynamics method allows us to study the atomic mechanisms of diffusion and their influence on the stability of the quasicrystalline phase.
The influence of alloying elements on the phase transition is also of considerable interest. Addition of small amounts of other elements can stabilize the quasicrystalline phase or, conversely, accelerate the crystallization process. This is due to changes in the electronic structure and Gibbs energy of the phases. The practical application of Al–Cu–Fe alloys depends on the ability to control the phase composition and microstructure. Heat treatment and mechanical action can be used to obtain materials with specified properties. Developing optimal processing modes requires a deep understanding of the phase transition mechanism and its dependence on external conditions.
Thus, the study of the phase transition in Al–Cu–Fe is an important task of materials science, which has both fundamental and practical significance. Further research aimed at studying the atomic mechanisms and thermodynamics of the phase transition will make it possible to create new materials with unique properties.
Author: F. Dénoyer, P. Launois, T. Motsch, M. Lambert
Institute: Laboratoire de Physique des Solides, (Associé au CNRS), Université Paris-Sud, Bâtiment 510, 91405 Orsay Cédex, France, Laboratoire Léon Brillouin, (CEA-CNRS), CEN Saclay, 91191 Gif-sur-Yvette Cédex, France