Size Effect on the Micro-Extrusion Forming of Zr-Based Amorphous Alloys

Micro-extrusion of a Zr-based bulk metallic glass in its super-cooled liquid state is explored as a method to create objects of cup-shaped micro-parts. The effects of overall dimensions of the samples and the ratio of inner diameter to out diameter (i) on the forming are determined. The results reveal that the apparent viscosity of the forming liquid increases along with the rises of i or with the decrease of the overall dimensions, and the increasing speed is more quickly while i is greater than 0.833, which suggest that there exists significant size effect. More generally, the results suggest that large i, and a low overall dimensions are attributes indicating difficulty for forming.