Size-independent Shear Band Formation in Amorphous Nanowires made from Simulated Casting

Molecular dynamics simulations indicate that surfaces strongly influence the strain localization behavior of amorphous nanowires in tension. A sample preparation routine that simulates casting was employed to facilitate the relaxation of the sample surface. Samples as short as 15 nm (7.5 nm in diameter) form dominant shear bands during deformation. The elastic energy release during plastic deformation is sufficient to provide the excess potential energy required for the shear band nucleation at rather small sample sizes. The results show that shear band formation is almost size-independent and is bounded only by its own length scale.Comment: 13 pages, 3 figures, to be appeared in Appl. Phys. Let

Structural transformation and localization during simulated nanoindentation of a non-crystalline metal film

A simulation study demonstrates that localization can arise as the result of the breakdown of stable quasi-crystal-like atomic configurations. Samples produced at elevated quench rates and via more energetic processes contain a lower fraction of such configurations and exhibit significantly less pronounced localization and shorter spacing between bands. In the samples produced by the lowest quench rates localization is accompanied by the amorphization of material with initially quasi-crystal-like medium range order. This result is of particular significance in light of recent experimental evidence of local quasi-crystal order in the most stable of the bulk metallic glasses.Comment: 13 pages, 3 figure