In situ modulation of mechanical properties in additively manufactured β-titanium alloys

Additive manufacturing (AM) enables complex metallic parts with controlled microstructures and mechanical properties. Metastable β-titanium alloys, such as Ti-20Nb-6Ta, are promising for biomedical applications due to biocompatibility and tunable elastic modulus, yet their microstructural evolution during AM is underexplored. This study investigates Ti-20Nb-6Ta processed via laser-based powder bed fusion (PBF-LB), varying laser power and scanning speed to evaluate effects on porosity, hardness, and microstructure. Low-to-medium energy inputs produce a metastable α" + β + ω microstructure with low elastic modulus (52–63 GPa) and hardness (232–276 HV), while high energy induces in situ aging, forming a nanoscale α + β microstructure with enhanced hardness (391 HV) and higher modulus (103 GPa). These findings demonstrate the potential of PBF-LB to produce parts with tailored microstructures and mechanical properties by varying processing parameters. Linking processing parameters to microstructural outcomes provides a framework for optimizing AM of β-Ti alloys, advancing the design of next-generation biomedical implants and other applications requiring precise property control. • Investigated Ti-20Nb-6Ta β-titanium alloy processed via laser-based powder bed fusion (PBF-LB). • Demonstrated that processing parameters (laser power, scan speed) strongly affect porosity, hardness, and microstructure. • Identified low-to-medium energy inputs yielding a metastable α″ + β + ω microstructure with low modulus (52–63 GPa) and hardness (232–276 HV). • Showed that high energy input promotes in situ aging, forming nanoscale α + β microstructures with higher hardness (391 HV) and modulus (103 GPa). • Highlighted potential of PBF-LB to produce functionally graded parts with tunable properties, enabling next-generation biomedical implants.