X-ray diffraction study of the icosahedral AlCuFe quasicrystal at megabar pressures

• Published in: Materials letters Vol. 161; pp. 13 - 16
• Main Authors: Takagi, Sota, Kyono, Atsushi, Mitani, Saki, Sugano, Neo, Nakamoto, Yuki, Hirao, Naohisa
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2015
• Subjects: Anvils; Atomic structure; Compressing; Diamond anvil cell; Diffraction; High pressure; Icosahedral phase; Icosahedral quasicrystal; Quasicrystals; Unit cell; X-ray diffraction study; X-rays; Diamond anvil cell; X-ray diffraction study; Icosahedral quasicrystal; High pressure
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2015.08.057

We report in-situ synchrotron X-ray diffraction study of icosahedral (i)-AlCuFe quasicrystal (QC) at high pressure up to 104GPa under ambient temperature using the diamond anvil technique. With compression, there is no obvious change of the diffraction pattern within the measured pressure range. Five characteristic peaks from the i-AlCuFe QC maintain up to 104GPa. The unit cell volume of the i-AlCuFe QC decreases monotonously until 72GPa. The experimental P–V compression curve below 72GPa was fitted to the Birch–Murnaghan equation of state with V0=2023(19)Å3, K0=131(7)GPa, K′=4.0 (fixed). The resulting EoS parameters are approximately consistent with those observed in previous study. A discontinuous volume change is observed between 72 and 75GPa. These observed results indicate a phase transition from i-AlCuFe QC to an approximant crystal (AC) which has a similar local atomic arrangement as the QC. This study suggests that i-AlCuFe QC maintains its structure at least up to 72GPa and then transforms to AC with small displacement of atoms. •We report high-pressure XRD study on icosahedral Al-Cu-Fe quasicrystal.•Five characteristic peaks from the quasicrystal continue up to megabar pressures.•The icosahedral Al-Cu-Fe quasicrystal maintains its structure at least up to 72 GPa.•The icosahedral Al-Cu-Fe quasicrystal transforms to approximant crystal above 75 GPa.•New small peak from approximant crystal appears above 89 GPa.