Molecular dynamics simulation of the break of magnesium nanowires

We carried out molecular dynamics simulations of the tensile break of Mg nanowires at 4 and 300K and examined how the minimum cross-section S-m (measured by number of atoms) of a constrictive neck diminishes with nanowire stretching. For both [0001]- and [0 (1) over bar 10]-oriented nanowires, the histogram of S-m at 4K shows a peak at S-m = 1. This result indicates that Mg nanowires can be reduced to single-atom contacts at 4K in agreement with experimental observations. At the beginning of stretching, the tensile force of Mg nanowires at 4K is much larger than that at 300 K, but the forces at 4 and 300K become comparable in later deformation stages. We observed that the stretching of Mg nanowires at 300K often produces long icosahedral nanowires similar to the one reported in the stretching simulations of some FCC nanowires. These icosahedral nanowires yield a large peak at S-m = 5 in the S-m histogram at 300 K. It is found that this S-m = 5 peak depends on the initial size of nanowires and decreases for thicker nanowires. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim