Influence of ECAP Parameters on Electrical Conductivity and Hardness of Pure Cu

Abstract

In this study, the ECAP pprocess was conducted using two different dies of channel angles (Φ) 120° and 90° to extrude pure Cu for 2 and 6 passes of route Bc at room temperature. Optical Microscopy (OM) was used to study the microstructure of Cu before and after ECAP processing. Vickers's microhardness was measured along the transvers section of the Cu billets. The electrical conductivity of the Cu billets was measured at room temperature and expressed as a relative percentage of the international annealed copper standard. 2-passes using the two dies revealed an elongated ultrafine-grained structure that aligned parallel to the extrusion direction. 6 passes using the 90°-die resulted in more ultrafine-grained equiaxed structure compared to the Cu billets processed through the 120°-die. Processing through 6-passes revealed a significant increase in the Cu Vickers's microhardness by 56% and 72% through processing using the using the 120°-die and 90°-die, respectively when it put in comparison with the as-annealed samples. The electrical conductivity finding revealed that ECAP processing up to 6-passes resulted in insignificant decrease of 6.6% compared to the as-annealed counterpart which indicated that ECAP processing can strengthen the Cu billets without losing its electrical conductivity