Additive Friction Stir Deposition (AFSD) is a promising solid-state additive manufacturing process for producing metallic parts, particularly aluminium components with low defect levels and controlled properties. AFSD utilizes the frictional heat generated at the interface between a rotating feedstock and a substrate to plastically deposit material layer by layer under a controlled axial force. This approach enables solid-state bonding of similar or dissimilar materials in successive layers, allowing the fabrication of three-dimensional components directly from digital design data without melting the material.

This work investigates AFSD processing of Al7075 to establish a clear understanding of the relations between processing parameters and the resulting micro and macro structural properties. The study is based on a controlled parameter investigation, and comparisons are made with conventionally manufactured Al7075 components.

Microstructural characterisation and mechanical testing were performed on the as-deposited material, and the results were evaluated in relation to the observed geometric features and parameter–response correlations. The AFSD-processed samples exhibit refined grain structures and a distinct mechanical response, reflecting the characteristic thermomechanical conditions imposed during solid-state deposition. These findings provide insight into how specific AFSD processing parameters influence material evolution and support the broader assessment of AFSD as a viable route for manufacturing high-strength aluminium alloys.