• Sub-transus heat treatment (800°C) transforms martensitic structure into fine lamellar α+β, improving ductility by 75% while retaining high strength.
• Super-transus heat treatment (1050°C) produces coarser lamellar structure, further enhancing ductility but with a 10% reduction in ultimate tensile strength.
• Optimal mechanical properties (UTS 1100 MPa, elongation 14%) achieved with sub-transus HT, comparable to wrought Ti-6Al-4V.
• Post-process heat treatment is essential for tailoring LPBF Ti-6Al-4V for aerospace and biomedical applications, ensuring reliability and performance.