Stable icosahedral phase in Mg–Zn–Gd alloy

Microstructural evolution including the stability of icosahedral phase (I-phase) in Mg95.9Zn3.5Gd0.6 alloy, before and after extrusion, has been investigated. The results indicate that the I-phase in Mg95.9Zn3.5Gd0.6 alloy is a face-centered icosahedral quasicrystal with stoichiometric composition of Mg42Zn50Gd8 and that this I-phase has excellent thermal stability up to 713 K. The W-phase and W′-phase, which are considered approximate crystalline equivalents of I-phase, have also been observed in the as-extruded alloy.