Mechanical properties of platinum nanowires: An atomistic investigation on single-crystalline and twinned structures

We present a systematic investigation on the mechanical properties of platinum nanowires with single-crystalline and fivefold twinned structures by means of atomistic simulations. The results show that the Young’s moduli of both types of nanowires are significantly higher than that of bulk counterpart. Furthermore, the fivefold twinned nanowire generally exhibits a higher elastic modulus than the single-crystalline one. The introduction of the twinned structures enhances the yielding strength of the nanowires but remarkably lowers their ductility. The initiation of the yielding mechanism of the two types of nanowires is through a nucleation process and the activity of Shockley partial dislocations under external stress. However, due to the obstacle to partial dislocations, the twin boundaries have been found to be simultaneously destructive, initiating the fracture of twinned nanowire. A comparison of the results with those of other fcc nanowires has indicated that the nonlinear elasticity and the yielding strain should also be responsible for the yielding strength of the nanowires.