• Friction stir processing effectively eliminates internal porosity and refines the grain structure of additively manufactured Ti-6Al-4V, leading to a 25% increase in yield strength.
• The combination of FSP and heat treatment produces a bimodal microstructure that enhances both strength and ductility, overcoming the typical strength-ductility trade-off.
• Fatigue life is improved by 40% due to the reduction of stress concentrators and the homogenization of the microstructure.
• The proposed post-processing route is industrially scalable and can be integrated into existing AM production lines, offering a cost-effective solution for high-performance applications.