Significant strengthening of nanocrystalline Ni sub-micron pillar by cyclic loading in elastic regime

Abstract

The influence of cyclic load, with the maximum stress well within the elastic regime, on the strength of nanocrystalline (nc) nickel was investigated through quasi-static compression experiments on cyclic-loaded sub-mu m-sized pillars, fabricated through electron beam lithography and electroplating. Results show that prior-cycling enhances both yield and flow strengths of nc Ni without significant loss in plasticity. Changes in strain-rate sensitivity and activation volume for deformation upon cycling were measured and utilized to discuss possible mechanisms responsible for the observed strengthening. (C) 2017 Acta Materialia Inc Published by Elsevier Ltd. All rights reserved.