Superplastic nanoforging of Pt-based metallic glass with dies of Zr-BMG and glassy carbon fabricated by focused ion beam

This paper introduces a technique for fabricating nano-structures through super plastic nano-forging of metallic glass using nano-scale dies that are fabricated by a focused-ion beam (FIB). FIB-machining characteristics of glassy carbon and Zr-based metallic glass have been studied and are useful for fabricating nano-scale dies because of the isotropic homogeneity of their amorphous structures. We used the dies to nano-forge Pt48.75Pd9.75Cu19.5P22 metallic glass. The thin foil specimens were heated in a small furnace and compressively loaded in a small vacuum chamber. Dies, a die-forged 1 mu m-diameter micro-gear, and both 800 and 400nm periodic nano-structures for optical applications were demonstrated. We observed the effects of thermal expansion and contact angle between the working material and the die materials on nano-formability. Metallic glasses are highly useful as materials for nano-imprinting and as die materials for FIB nano-machining.