Effect of process parameters on strength and hardness of AA1100 fabricated by friction stir additive manufacturing

This study investigates the process–property relationships in AA1100 aluminium alloy fabricated via Friction Stir Additive Manufacturing (FSAM), with a focus on optimising ultimate tensile strength (UTS) and Vickers microhardness through parameter tuning. A Taguchi L4 orthogonal array was employed to systematically vary tool rotational speed (900 and 1120 RPM), feed rate (25 and 40 mm/min), and tilt angle (1° and 2°), enabling quantitative analysis of main effects via analysis of means (ANOM). Results reveal that tilt angle is the most influential factor for UTS (Δ = 2.73 MPa), with a 1° setting delivering the highest UTS of 91.89 MPa by promoting symmetric stirring and defect‐free interlayer bonding. Conversely, rotational speed dominates hardness evolution (Δ = 1.2 HV), where 1120 RPM enhanced dynamic recrystallization and yielded a peak average hardness of 36.63 HV. The UTS variation across runs was limited to approximately 3 MPa and hardness fluctuation was within 1.4 HV and this proved the process stability of FSAM for AA1100 and its capability to produce dimensionally and structurally consistent builds. The interplay between parameters highlights a trade‐off: settings optimal for strength differ from those maximising surface hardness, necessitating application‐ specific process selection. These findings position FSAM as a viable, energy‐efficient route for manufacturing dimensionally precise, mechanically stable, corrosion‐resistant aluminium components, especially for aerospace, marine, and structural applications. Future work can focus on advanced microstructural characterisation, fatigue analysis and machine learning based predictive modelling for FSAM of aluminium alloys.