Precision and Micro Machining of Metallic Glasses (Formability of Zr Based Metallic Glasses in the Supercooled Liquid State)

Abstract

Amorphous alloys with the wide supercooled liquid region are called metallic glasses. In the supercooled liquid state, the metallic glasses exhibit superplasticity, which suggests the possibilities of forming the metallic glasses into various intricate shapes. In this paper, formability of two types of Zr based metallic glass; Zr75Cu19Al6 and Zr55Cu30Al10Nis (atomic%) are examined in the supercooled liquid state. The example metallic glasses showed superplasticity under compressive stress and high thermal stability in the supercooled liquid state. Furthermore, forming accuracy of the example metallic glasses was better than one micrometer. As the application of such precise forming, a concave mirror with a 10 mm diameter was formed. The profile error of the mirror was 0.5 μm and the surface roughness (Rmax), 90 nm. This superplastic forming of the Zr based metallic glasses is expected to be used for the production of various components of high precision and intricate shape. © 1999, The Japan Society of Mechanical Engineers. All rights reserved.