Effect of rotational friction extrusion on microstructure and mechanical properties of 6061 aluminum alloys with different aging states

Abstract

6061 aluminum alloys with different aging states were prepared by rotational friction extrusion （RFE）. The effect of RFE on the microstructure and mechanical properties of 6061 aluminum alloys with different aging states was investigated. The results show that the refractory AlFeMnSi phase of 6061 aluminum alloys can be broken by using RFE， resulting in the fine and uniform distribution of the AlFeMnSi phase in the alloy. Under the combined effects of frictional heat and deformation during RFE processing， the pre-precipitated coarse Mg2Si phase is dissolved and re-precipitated， resulting in that the pre-precipitated coarse Mg2Si phase has no effect on the particle stimulated nucleation （PSN） mechanism in the dynamic recrystallization of the material. Therefore， the size of grain exhibits negligible change by RFE. RFE reduces the strength of as-quenched 6061 aluminum alloys， while the strength of 6061 aluminum alloys with a long-term aging state can be increased by RFE. However， there are holes inside the material processed by RFE， which reduce the elongation of the alloys.

Keywords

• 6061 aluminum alloy
• rotational friction extrusion
• precipitated phase
• dynamic recrystallization