Core-shell double phase crystal in an yttrium-containing Zr-based bulk metallic glass

In this article, we report a novel core-shell structured quenched-in crystal detected in annealed (Zr0.51Cu0.207Ni0.12Al0.163)99.5Y0.5 bulk metallic glasses. A monoclinic Y2O3 (a = 1.388 nm, b = 0.351 nm, c = 0.863 nm, and β = 100.09°) is identified to be the core phase through detailed transmission electron microscopy study, which is shelled by an orthorhombic crystal (a = 0.69 nm, b = 0.75 nm, and c = 0.74 nm). The reason for the formation of this core-shell structure is discussed.