Integrated Assessment of Microstructure, Mechanical Response, and Corrosion Behaviour in Laser Powder Bed Fused Ti-5Al-5V-5Mo-3Cr

Ti-5Al-5V-5Mo-3Cr, commonly referred to as Ti-5553, is a metastable β titanium alloy of increasing interest for aerospace and biomedical applications owing to its attractive combination of strength, hardenability, toughness, and corrosion resistance. Laser powder bed fusion (LPBF) enables the fabrication of geometrically complex Ti-5553 components; however, rapid solidification and repeated thermal cycling strongly affect defect formation, surface morphology, phase constitution, and the resulting mechanical and electrochemical performance. In this study, as-built Ti-5553 specimens were fabricated by means of LPBF and assessed through an integrated experimental approach combining powder analysis, density measurement, X-ray computed tomography, surface roughness evaluation, optical microscopy, scanning electron microscopy, X-ray diffraction, nanoindentation, tensile testing, and corrosion testing.
The fabricated specimens achieved near-full densification, with a relative density of 99.95%, supported by computed tomography and microstructural observations. X-ray diffraction indicated a predominantly metastable β-phase matrix in the as-built condition, consistent with the β-stabilising chemistry of Ti-5553 and the rapid cooling associated with LPBF. Tensile testing showed an ultimate tensile strength of approximately 800 MPa and an elongation of 20%, indicating a favourable strength–ductility balance without post-processing. Corrosion assessment further suggested stable electrochemical behaviour, highlighting the influence of the as-built surface condition and microstructure on environmental performance. Overall, this work establishes an experimental baseline linking powder characteristics, build quality, microstructure, mechanical response, and corrosion behaviour in LPBF Ti-5553. The results establish a processing–microstructure–property baseline for selecting suitable post-processing treatments and advancing LPBF Ti-5553 toward biomedical applications.