Apparently homogeneous but intrinsically intermittent flow of taper-free metallic glass nanopillars

Taper-free small pillars of a Cu-based metallic glass with aspect ratios of c = 3 and 0.7 were tested in situ. With c = 3, decreasing the diameter D to similar to 120 nm caused the pillars to show apparently homogeneous deformation that was intrinsically accommodated by many coordinating local shear transformations (STs). For taper-free pillars of c = 0.7, at D > 300 nm regimes, a confinement, which prevents shear bands from propagating, does not have any noticeable effect on nucleation/formation of local STs. The results are discussed in terms of a micromechanical model. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.