Influence of Y ₂ O ₃ Addition on the Microstructure and Mechanical Properties of Additive Manufactured Ti6Al4V

ABSTRACT Laser powder bed fusion (LPBF)‐fabricated Ti6A4V alloys often suffer from insufficient comprehensive mechanical properties and pronounced anisotropy. In contrast, the introduction of rare earth elements offers a promising approach to performance optimization. In this study, Ti6Al4V‐ x Y 2 O 3 alloys were produced by incorporating different mass fractions of Y 2 O 3 particles into Ti6Al4V powder, followed by LPBF processing, and their microstructural characteristics and mechanical properties were systematically investigated. The results show that the addition of 0.2 wt.% Y 2 O 3 induces significant grain refinement, reducing the β grain size from 92.3 to 60.4 µm and the α′ martensitic lath size from 10.4 to 8.6 µm. At this composition, the alloy achieves an optimal combination of mechanical properties, with the yield strength increased from 1126 to 1208 MPa and the ultimate tensile strength from 1259 to 1331 MPa. This study provides new insights and experimental evidence for tailoring the microstructure and enhancing the mechanical performance of LPBF‐processed titanium alloys via rare‐earth oxide modification.