Influence of strain rate on ultimate tensile stress of coarse-grained and ultrafine-grained copper

In the present paper OFHC (oxygen free high conductivity) copper was tested by static and dynamic tensile tests at room temperature owing to strain rate investigation. Because of coarse-grained (CG) and ultrafine-grained (UFG) microstructure observation the copper was subjected to drawing and ECAP processes. The investigation of strain rate and microstructure was focused on the ultimate tensile stress (UTS) after the tensile tests. Following this study, it was found that strain rate is an important characteristic influencing the mechanical properties of copper. The ultimate tensile stress grew with strain rate increasing and this effect is more visible at high strain rates (ε˙~102s−1). Moreover, it was revealed that strain rate hasn't got any influence on the failure mechanism of the copper on the other hand it has an influence on the values of dimple size. While strain rate increases the dimple size decreases.