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Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Structural phase transitions from and to the quasicrystalline state
1Laboratory of Crystallography, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland. Steurer@mat.ethz.ch
Acta Crystallographica. Section A, Foundations of Crystallography
|December 23, 2004
Summary
Phase transitions involving quasicrystals are driven by shared structural units, leading to stable interfaces and nanodomain structures. Atom diffusion is essential, as purely displacive transitions are impossible due to topological incompatibilities.
Area of Science:
- Materials Science
- Crystallography
- Condensed Matter Physics
Background:
- Quasicrystalline materials exhibit unique structural properties influencing their phase transitions.
- Interfaces between quasicrystalline and crystalline phases are characterized by low energy due to shared structural units.
- Topological incompatibilities between quasiperiodic and periodic structures preclude purely displacive phase transitions.
Purpose of the Study:
- To elucidate the mechanisms and characteristics of phase transitions involving quasicrystalline materials.
- To explain the stability of nanodomain structures formed during these transitions.
- To discuss various experimentally observed phase transition pathways.
Main Methods:
- Analysis of structural peculiarities in quasicrystalline phase transitions.
- Investigation of atomic diffusion requirements for phase transformation.
- Review of experimental observations under varying conditions (temperature, pressure, irradiation, milling).
Main Results:
- Phase transitions are characterized by low-energy interfaces and stable orientationally twinned nanodomain structures.
- Significant atomic diffusion is necessary for transitions due to topological constraints.
- Icosahedral ordering facilitates quasicrystal formation from liquid alloys and metallic glasses.
Conclusions:
- Phase transitions in quasicrystals are fundamentally linked to their unique cluster-based structure.
- Atomic diffusion is a critical factor, not just atomic rearrangement.
- Understanding these transitions is key for controlling material properties and synthesis.
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