Compression behaviour and pressure-induced strain of icosahedral Zn-Mg-Y quasicrystal

The compression behaviour and pressure-induced disorder of an icosahedral Zn55Mg35Y10 quasicrystal has been investigated by means of an in-situ angle-dispersive X-ray powder diffraction method using synchrotron radiations. The icosahedral structure was found to be essentially stable under high pressures up to 70 GPa and at 1 bar after recovered from 70 GPa. However, it should be noted that all peaks of the X-ray diffraction after recovered were broad even at 1bar. This indicates that the recovered sample contains a lot of pressure-induced strains even though it was an icosahedral quasicrystal. It was found that there was a linear relation between Q// (physical momentum) and HWHM (Half Width at Half Maximum) of the X-ray diffraction peaks of the sample recovered from 70 GPa. On the other hand, there was no correlation between Qperpendicular (phason momentum) and HWHM. In addition, there was no linear relation between (Qperpendicular/Q//)2 and (HWHM/Q//)2. These analyses indicate that the pressure-induced strains in the extremely strained Zn-Mg-Y quasicrystal recovered from 70 GPa are explained by neither of the icosahedral glass nor the frozen-in phason strain models, and explained well by the simple lattice (phonon) strain