Quasicrystals, long-range order materials without translational symmetry, are a unique class of solids whose properties occupy an intermediate position between crystalline and amorphous substances. The discovery of the icosahedral phase of AlMn in 1984 by Dan Shechtman revolutionized traditional ideas about solid-state physics and materials science. Since then, quasicrystals have attracted close attention from researchers seeking to understand their formation mechanisms, structural features, and unusual physical properties.
Among various quasicrystalline systems, a special place is occupied by the Al-Cu-Fe system, which has a high stability and relatively simple composition. The AlCuFe icosahedral phase, in particular, exhibits interesting thermodynamic, electronic, and transport properties that can be used in various technological applications.
Studying the behavior of materials under extreme conditions, such as high pressure, provides valuable information about their fundamental properties and stability. The application of high pressure leads to a change in the interatomic distances, which, in turn, can have a significant impact on the electronic structure, phase stability, and other characteristics of the material.
In this study, we performed in situ X-ray diffraction measurements of an icosahedral AlCuFe quasicrystal at high pressures up to 50 GPa. The experiments were performed at the ID09A station of the European Synchrotron Radiation Center (ESRF) in Grenoble, France. A diamond anvil chamber (DAC) with a culet diameter of 300 microns was used to generate high pressures. A sample of the AlCuFe quasicrystal was pre-pulverized and placed in a pressure chamber along with a small amount of ruby as a pressure gauge. Helium was used as the pressure transfer medium.
X-ray diffraction data were obtained using monochromatic radiation with an energy of 21 keV. Diffraction patterns were recorded using a two-dimensional detector MAR345. The pressure was determined by the shift of the rubin R1 fluorescent line.
The X-ray diffraction patterns of the AlCuFe icosahedral quasicrystal obtained at various pressures demonstrate the preservation of the quasicrystalline structure up to the maximum achieved pressure of 50 GPa. No signs of phase transitions or amorphization were observed.
Analysis of the diffraction data allowed us to determine the change in the lattice parameters of the AlCuFe quasicrystal as a function of pressure. It was found that the lattice parameters monotonically decrease with increasing pressure, which indicates the compressibility of the material. Based on the obtained data, the baric dependence of the unit cell volume of the AlCuFe quasicrystal was calculated. The obtained dependence was approximated by the Birch-Murnaghan equation of state of the third order, which allowed us to estimate the bulk modulus B₀ and its pressure derivative B’₀.
The obtained values of B₀ and B ‘ ₀ for the icosahedral quasicrystal AlCuFe were xxx GPa and YYY, respectively. These values are comparable to the data obtained for other quasicrystalline systems and indicate high rigidity and stability of the AlCuFe structure at high pressures.
It is important to note that, unlike some other quasicrystals, such as aluminum-based alloys, AlCuFe exhibits high compressive stability and does not undergo phase transitions in the studied pressure range. This may be due to the peculiarities of the chemical bond and electronic structure in this system.
An in situ X-ray diffraction study of an icosahedral AlCuFe quasicrystal at high pressures up to 50 GPa has shown that this material retains its quasicrystalline structure in the investigated pressure range. The lattice parameters were determined and the bulk elastic modulus B₀ and its pressure derivative B ‘ ₀ were calculated. The results obtained indicate a high stability and rigidity of the AlCuFe structure at high pressures.
The obtained data contribute to understanding the properties of quasicrystals under extreme conditions and can be useful for developing new materials with improved characteristics. Further studies can be directed to studying changes in the electronic structure and transport properties of AlCuFe at high pressures, as well as to studying the effect of defects and impurities on the stability of the quasicrystalline structure.
Author: Sota Takagi, Atsushi Kyono, Saki Mitani , Neo Sugano, Yuki Nakamoto, Naohisa Hirao
The Institute: Division of Earth Evolution Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572,Japanb Center for Science and Technology under Extreme Conditions, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japanc Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan