The effect of prior deformation on mechanical behavior as a function of size was investigated for body-centered cubic Mo pillars. Experiments were performed using focused ion beam manufactured [001] and [235] Mo micro/nanopillars, which were compressed, re-focused ion beam machined, and compressed again. Unlike in bulk materials, pre-straining had a negligible effect on stress–strain behavior of the pillars, suggesting that dislocation storage does not occur in small-scale body-centered cubic specimens. The prevailing mechanism behind the size effect was attributed to dislocation nucleation mechanisms.

Effect of Pre-Straining on the Size Effect in Molybdenum Pillars. A.S.Schneider, B.G.Clark, C.P.Frick, P.A.Gruber, E.Arzt: Philosophical Magazine Letters, 2010, 90[11], 841-9