Abstract

The present work studies the influence of five-pass overlapping friction stir processing (FSP) on microstructure, mechanical properties and corrosion behavior of AA6061 alloy. The fine equiaxed grains were produced in large-area stir region of overlapping FSP and it was identified that the grain size of each overlapping pass is uniform in large area stir region (average grain size = 3.9 ± 3.5 µm). The five-pass overlapping FSP resulted in ductility enhancement while the strength remained inferior to that of parent metal due to thermal softening during FSP. On the other hand, corrosion resistance greatly improved after FSP due to the formation of a homogenous fine-grained structure and discontinuous precipitates.

Graphic Abstract

中文翻译：

---

重叠搅拌摩擦加工对AA6061合金组织，力学性能和腐蚀行为的影响

摘要

本工作研究了五遍重叠摩擦搅拌处理（FSP）对AA6061合金的组织，力学性能和腐蚀行为的影响。在重叠的FSP的大面积搅拌区域产生了细等轴晶粒，并且可以确定，每个重叠道次的晶粒尺寸在大面积搅拌区域均一（平均晶粒尺寸为3.9±3.5 µm）。五遍重叠的FSP导致延展性增强，而由于FSP期间的热软化，其强度仍然不如母材。另一方面，由于形成均质的细粒结构和不连续的析出物，FSP后的耐腐蚀性大大提高。

图形摘要