High strength Mg-Zn-Y alloy containing quasicrystalline particles

Abstract

A new magnesium alloy strengthened by icosahedral quasicrystalline particles and precipitates was developed by thermomechanical processes for an as-cast Mg-rich Mg95Zn4.3Y0.7 alloy. Quasicrystalline particles of 0.5-2 μm in size were distributed in the α-Mg matrix by the hot-rolling process, and nanoscale quasicrystals were also precipitated throughout the α-Mg grains during this thermomechanical process. The alloy exhibits high strengths and large elongations at room and elevated temperatures. High strength observed in the alloy is mainly due to the strengthening effect of large number of quasicrystals, where the volume fraction of quasicrystals is around 9%. The quasicrystalline phase is found to be in equilibrium with the α-Mg phase and stable against coarsening under deformation up to near the melting temperature of the eutectic. The stable quasicrystalline particle/matrix interface with a low interfacial energy can provide the improved mechanical properties of the alloy.