The influence of sample thickness on the tensile properties of pure Cu with different grain sizes

We investigate the effects of sample thickness on the tensile properties of pure Cu with different grain sizes. Tensile strength, ductility and work-hardening coefficient decrease with decreasing sample thickness when the t/d (sample thickness/average grain size) is smaller than a critical value. It is suggested that the thickness effects are governed by competition between the dislocation activities in the interior grains and surface grains.