Comparative Evaluation of Mechanical Behaviour and Machinability of WAAM-Fabricated Aluminium Alloys

This study presents an integrated evaluation of the mechanical properties and machinability of thin-walled aluminium alloys fabricated via Wire Arc Additive Manufacturing (WAAM), comparing them against conventional wrought counterparts. Experimental investigations were conducted through tensile testing, hardness measurement, surface characterisation, and cutting force analysis. The results reveal a critical performance trade-off: WAAM specimens demonstrated superior bulk mechanical properties, most notably a 44.36% increase in tensile strength, alongside enhanced elongation despite a marginal reduction in hardness. However, this structural advantage is counterbalanced by a significant machinability penalty. Frequency domain analysis using Power Spectral Density (PSD) revealed that inherent microstructural porosity in WAAM components triggers dynamic instabilities during machining. These irregularities make the material highly susceptible to high-frequency chatter, ultimately resulting in a 46.73% increase in surface roughness. By establishing a direct relationship between fabrication-induced microstructural defects and dynamic machining degradation, these findings emphasise the necessity for defect-aware, optimised hybrid manufacturing strategies to improve the industrial applicability of WAAM-fabricated structures.