Refinement of the icosahedral quasicrystalline phase and the grain size of Mg-9.25Zn-1.66Y alloy by high-ratio differential speed rolling

Differential speed rolling was applied to a Mg-9.25Zn-1.66Y alloy with an icosahedral quasicrystalline (I) phase to refine its cast microstructure by severe plastic deformation. The grain size was reduced to ∼1 μm. A higher speed ratio, which produces a higher shear strain, was more effective in breaking up the eutectic I phase structure and dispersing the broken particles into the matrix. The processed alloy exhibited a high yield stress of 337 MPa and a good elongation of 10.7%.