(Icosahedral phase+α-Mg) two phase microstructures in the Mg–Zn–Y ternary system

Structural applications of monolithic icosahedral phase (I-phase) materials have been limited by the brittleness of I-phases. Composite material design, including a ductile phase, can be a solution for the structural applications of the I-phase materials. Two phase microstructures, including thermodynamically stable I-phase, are studied in the Mg-rich corner of the alloy system Mg–Zn–Y. An (I-phase+α-Mg) eutectic microstructure is reported for the first time in the as-cast samples. By controlling thermal processing procedures, a very different (I-phase+α-Mg) microstructure from the eutectic microstructure can be developed, expanding the microstructural options available for the structural composite materials, comprising the I-phase and α-Mg solid solution.