Influence of specimen dimensions on the tensile behavior of ultrafine-grained Cu

Miniature dog-bone specimens with different sizes and geometries are frequently used to measure the tensile behaviors of nanostructured materials. Here we report a significant specimen dimensions influence on the tensile behavior of ultrafine-grained Cu: the elongation to failure, post-necking elongation and strain hardening rate all increase with increasing thickness or decreasing gauge length. The thickness effect is caused by the necking geometry and the effect of gauge length originates from the strain definition.