• In-situ ultrasonic vibration during LPBF reduces porosity by up to 40% and refines grain structure, leading to improved mechanical properties.
• Optimal vibration amplitude of 30 μm yields a 15% increase in yield strength and 20% improvement in elongation compared to conventional LPBF.
• Ultrasonic vibration enhances melt pool convection and promotes heterogeneous nucleation, resulting in fine equiaxed grains.
• The proposed technique offers a scalable and cost-effective method to enhance the performance of additively manufactured titanium alloys for aerospace and biomedical applications.