First stages of plasticity in three-point bent Au nanowires detected by in situ Laue microdiffraction

Abstract

The first stages of plasticity in three-point bent Au nanowires are investigated by in situ three-point bending tests in combination with Laue micro-diffraction. To separate the elastic and plastic deformation, loading–unloading cycles were performed with increasing load in each consecutive cycle. The storage of the first four geometrically necessary dislocations of [011⎯⎯](111) slip system is observed in the vicinity of both clamping points, which might be attributed to the local rotations induced by the rigid Si support. At later stages of the deformation, additional slip systems are activated either by the torsion of the nanowire or by unintentional indentation from the AFM tip. The cyclic loading–unloading approach combined with Laue microdiffraction thus allows to study the onset of plasticity in defect-scarce nanostructures deformed by bending, offering additional possibilities in studying the dislocation nucleation process in bent nano-objects, which are essential for future applications, e.g., in flexible electronics and nano-electromechanical systems. The authors gratefully acknowledge the financial support from the French National Research Agency through Project No. ANR-11-BS10-0014 MecaniX. They further thank the French CRG program committee for the allocated beamtime at the BM32 beamline at ESRF and L. Belliard at INSP in Paris (France) for providing the Si micro-trenches.