Microstructure evolution and mechanical properties of 2060 Al-Li alloy via friction stir additive manufacturing

Aluminum has low evaporation temperature and high reactivity with oxygen, and it could cause a lot of challenges during traditional melt-based additive manufacturing (AM) process. However, as a solid-state technology, friction stir additive manufacturing (FSAM) is expected to avoid the melting-solidification during entire manufacturing and solve these defects eventually. In this study, the microstructure evolution and mechanical properties of 2060 aluminum lithium alloy manufactured via FSAM were carried out at various process parameters. The results indicate that the best combined parameter could be obtained at rotational speed as 1600 r/min, translational speed as 300 mm/min and splice rate as 80%. Due to dynamic recrystallization from plastic deformation and heat input, finer equiaxed grains with size between 2 and 5 µm could be obtained in the nugget zone and a maximum microhardness could reach 135 HV.