三辊行星轧制过程中ACR紫铜管的组织和性能演变

Microstructure and properties of ACR copper tube during three-roll planetary milling process

采用金相显微镜、布氏硬度仪以及激光热导仪对三辊行星轧制过程中紫铜管的组织和性能进行研究。结果表明:在三辊行星轧制过程中,先后存在着加工硬化和动态再结晶软化两个过程,急剧大变形使粗大的铜晶粒破碎、滑移并产生大量热量,致使变形区温度急剧上升,最终获得了动态再结晶组织;与组织转变相对应,硬度值表现为随变形量的增大而增加,因加工硬化和动态再结晶的共同作用保持稳定,再结晶完成时硬度值下降;由于空洞等缺陷在变形过程中被抵消,材料的热导率增大,再结晶开始后,晶粒变得细小,热导率下降。

The microstructure and properties of the pure copper tube during the rolling process of a three-roll planetary mill were studied using optical microscope, Brinell＇s hardness measurements and laser-thermal rating measurements. The in-situ microstructure evolutions, resulting from both work-hardening and dynamic recrystallization softening during the three-roll planetary milling process were summarized systematically. The results show that, corresponded with the transformation of microstructure, the hardness increases along with the augmentation of the deformation, keeps fluctuation responsible for the coactions between the work-hardening and the dynamic recrystalliza- tion and drops when the recrystallization completes. The thermal conductivity of the copper tube increases, because the cavity and other defects are bucked in the processes of the deformation. After the recrystallization, the thermal conductivity decreases along with the diminution of the crystal grain.