Effect of cold rolling on microstructure and mechanical properties of copper subjected to ECAP with various numbers of passes

Microstructure and mechanical properties of copper subjected to 1–10 ECAP passes via route Bc were compared with those for further cold rolled specimens. Microstructure was studied by means of TEM and EBSD analysis in three orthogonal sections. Rolling caused transformation of reasonably equiaxed structure after ECAP into lamellar one due to geometrical effect of deformation, but almost no additional grain refinement occurred during rolling. Significantly higher extent of HABs (about 20% irrespectively to passes number) was found after rolling. This was associated with more pronounced dynamic restoration process during rolling. Mechanical properties were estimated by tension testing at room temperature. Yield strength increased by ∼100 MPa after rolling due to finer boundary spacing according to Hall–Petch relationship.

► Copper was cold rolled after ECAP. ► Structure and mechanical properties after ECAP and ECAP with rolling were compared. ► Boundary spacing decreased due to geometrical effect of rolling strain. ► HABs fraction increased significantly after rolling. ► Strength increased according to Hall–Petch relationship after rolling.