高纯铜热变形过程中的变形行为及其动态再结晶机制研究

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

摘要:

高纯铜靶材的微观组织结构对溅射薄膜的质量有重要影响，本工作从靶材热加工的角度研究了铜靶材的组织演变规律和动态再结晶机制。通过等温压缩实验研究高纯铜在变形温度为500~650 ℃、应变速率为0.01~10 s^–1条件下的热变形行为。结果表明：组织的演变及再结晶机制与Zener-Hollomon参数（Z）紧密相关。随着温度上升和应变速率下降，lnZ值降低，平均晶粒尺寸逐渐减小，组织均匀性及动态再结晶程度提高，并且织构取向由强变形织构Cube ND{001}<110>转变为Cube{001}<100>、Goss{011}<100>等再结晶织构。在不同lnZ值下发生了动态再结晶机制的转变，高lnZ值时（500 ℃、 10 s^–1）发生局部再结晶，为非连续动态再结晶（discontinuous dynamic recrystallization，DDRX）的方式；中lnZ值时（550 ℃、1 s^–1）再结晶程度提高，发生取向差均匀增加和晶格渐进旋转两种不同的连续动态再结晶（continuous dynamic recrystallization，CDRX）机制；低lnZ值时（650 ℃、10 s^–1）发生晶格渐进旋转的连续动态再结晶和晶粒“夹断”的几何动态再结晶（geometric dynamic recrystallization，GDRX），在650 ℃、10 s^–1这一低lnZ值时得到均匀细小的组织和弱的织构强度。该研究可为高纯金属溅射靶材的热加工工艺优化提供理论指导。

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.