Microstructure and Properties of 6061 Aluminum Alloy by Additive Friction Stir Deposition

Additive friction stir deposition (AFSD) enables solid-state, layer-by-layer metal deposition, minimizing defects and elemental loss from melting. Consequently, AFSD is highly effective for manufacturing aluminum alloys. Systematic studies indicate that grain structure influences properties along different processing directions in AFSD aluminum alloys. Accordingly, this study used AFSD to fabricate an aluminum alloy wall and rigorously characterized its microstructure and mechanical properties in both the XOY plane (X direction) specimen and the YOZ plane (Z direction) specimen. Results demonstrate that AFSD-fabricated 6061 aluminum alloys exhibit refined grains. Microhardness tests revealed directional variation, with the YOZ plane (Z direction) specimens showing lower hardness. Tensile tests showed that the transverse direction (X direction) specimens had slightly higher tensile strength than the deposition direction (Z direction) specimens. This study offers theoretical guidance for optimizing AFSD metal fabrication and provides data supporting the broader adoption of AFSD-fabricated 6061 aluminum alloys.