On the stress‐strain curves in gold and aluminum nanowires

The engineering stress-strain curves of gold and aluminum nanowires have been investigated by means of Molecular Dynamics. Nanowires were stretched at constant strain rate and a temperature of 4.2 K. Atoms at fixed positions with velocities randomly distributed according to Maxwell distribution were taken as initial conditions. Jumps observed to occur in the stress-strain curves are associated to atoms that move from the bulk to the surface. Averaging over many realizations allows to conclude that, beyond the yield point, the system does not harden, in line with experimental results. Varying the nanowires shape factor allowed to identify surface effects, crucial in these extremely small systems (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)