The effect of prior deformation on mechanical behavior as a function of size is investigated for body-centered cubic (bcc) molybdenum (Mo) pillars. Experiments were performed using focused ion beam (FIB) manufactured [0 0 1] and [2 3 5] Mo micro/nanopillars, which were compressed, re-FIB machined, and compressed again. Unlike in bulk materials, pre-straining has a negligible effect on stress-strain behavior of the pillars, suggesting that dislocation storage does not occur in small-scale bcc specimens. The prevailing mechanism behind the size effect is attributed to dislocation nucleation mechanisms.
Philosophical Magazine Letters , 2010, 90 (11), 841-849.