He ion irradiation induced nanocrystallization in Cu50Zr45Ti5 glassy alloy

Partial nanocrystallization induced by ion irradiation can be used to improve the surface properties in metallic glasses. We investigated the crystallization behavior and the structure of the formed nanocrystalline phases in a melt-spun Cu50Zr45Ti5 glassy alloy irradiated with 140 keV He ions to a fluence of 1.7 × 1017/cm2. Crystalline nanoparticles were precipitated by He ion irradiation. The nanocrystalline phases were identified as a mixture of the orthorhombic Cu10Zr7 phase, tetragonal CuZr2 phase and monoclinic CuZr phase. Hardness enhancement was observed at a depth close to the projected range of the He ions, which was related to the formation of the crystalline nanoparticles.