Deformation Behavior and Related Dynamic Recrystallization Mechanism of High Purity Copper During Hot Deformation

Abstract:

The microstructure of high-purity copper targets has a significant impact on the quality of sputtered films. This study investigated the evolution of the microstructure and dynamic recrystallization mechanism of copper targets from the perspective of hot working. The hot deformation behavior of high-purity copper at temperatures ranging from 500 ℃ to 650 ℃ and strain rates from 0.01 s^–1 to 10 s^–1 was studied through isothermal compression experiments. The results show that the evolution of the microstructure and the recrystallization mechanism are closely related to the Zener-Hollomon parameter Z. As the temperature increases and the strain rate decreases, the lnZ decreases, and the average grain size decreases, both the microstructure homogenization and dynamic recrystallization enhance, and the texture transitions from a strong deformation texture of Cube ND{001}<110> to Cube{001}<100> and Goss{011}<100>. The dynamic recrystallization mechanism changes at different lnZ values. Local recrystallization occurs at high lnZ values, which is a discontinuous dynamic recrystallization (DDRX) mode. At middle lnZ value, the degree of recrystallization increases, the orientation difference increases uniformly and the lattice rotates gradually. At low lnZ values, continuous dynamic recrystallization (CDRX) of progressive rotation of lattice and geometric dynamic recrystallization (GDRX) of grain "pinching" occur. At low lnZ value of 650 ℃, 10 s^–1, homogeneous fine microstructure and weak texture strength are obtained. The research can provide theoretical guidance for the optimization of hot working technology of high purity metal sputtering targets.