Microstructure Evolution in the Rolled Mg97Zn1Y2 Alloy with Long-Period Stacking Phase upon Annealing

Mg97Zn1Y2 alloy (at%) has been studying nearly ten years as an elevated temperature creep resistant Mg-based alloy with long-period stacking (LPS) phase. The deformation processing had been performed upon the alloy so that a highly non-equilibrium state was looked forward to provide particularly advantageous material property profiles for it. Thus the texture evolutions in Mg97Zn1Y2 alloy processed by rolling and annealing the as-cast alloy at different temperatures, are investigated thoroughly. The microstructures of the alloy had been examined using general optical microscopy (OM), laser optical microscopy (LOM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM); the textures were analyzed by X-ray diffraction (XRD). The result shows that the second recrystallization texture had developed primarily when a preliminary annealing treatment of 500 � C for 2 hours was performed to the rolled alloy and that part of the LPS phase had evolved into another phase with hexagonal superstructure which is an approximant to a quasicrystal and even the quasicrystal.