Texture dependent strain rate sensitivity of ultrafine-grained aluminum films

We investigated the strain rate sensitivity (SRS) of freestanding ultrafine-grained aluminum films with similar thickness (~ 240 nm) and mean grain size (~ 275 nm) but highly dissimilar texture. For (110) textured bicrystalline films, flow stress increased by 14% (m = 0.017) as the strain rate was varied from ~ 7 × 10− 6/s to 5 × 10− 3/s. In contrast, for non-textured films the flow stress increased by more than 90% (m = 0.103) over a similar strain rate range. The drastic difference in SRS can be explained by texture-induced changes in deformation mechanisms of the films, as revealed by in situ TEM straining experiments.

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