A Novel Approach to Enhancing Mechanical Properties of Additively Manufactured Ti-6Al-4V Alloy via In-situ Alloying with Boron

• In-situ boron alloying during LPBF significantly refines the grain structure of Ti-6Al-4V, leading to improved strength and ductility. • The addition of 1.0 wt.% boron yields a 25% increase in yield strength and a 15% improvement in ductility without compromising elongation. • TiB precipitates act as heterogeneous nucleation sites, promoting the formation of fine equiaxed grains and acicular α' martensite. • This approach provides a cost-effective and scalable method to enhance the mechanical performance of additively manufactured titanium components for high-performance applications.