Formation of Nanotwins in Cold-Rolled Cu-Zn Alloy by Electric Current Pulses

Abstract

A significant number of nanotwins was fabricated in a cold-rolled Cu-Zn alloy after an electric current pulse (ECP) treatment in this study. Results showed that the formation of nanotwins was related not only to the α to β phase transformation, but also to the effect of the enhanced directional nucleation along the current direction during the heating caused by the ECP treatment. A theoretical analysis revealed that the nucleation rate of the higher conductivity phase (β phase) was significantly accelerated by the application of an electric current, which provided more nucleation places for the α phase during the subsequent rapid cooling process. Especially, during the cooling process, nanotwins with {111} twin planes in the α phase would be formed due to the stronger internal stress induced by the rapid cooling rate after the ECP treatment.