Seminar: Designing & Printing Dispersion Strengthened Ti-6Al-4V via Laser Powder Bed Fusion Additive Manufacturing

Abstract The anisotropy of the mechanical properties of Ti-6Al-4V additively manufactured (AM) via laser powder bed fusion (PBF-LB) is increased by the long and textured columnar prior beta grains that typically occur despite the high cooling rates (105–107 K/s). Additionally, both AM and conventionally fabricated Ti-6Al-4V exhibit dwell-fatigue sensitivity at room-temperature, resulting in premature failure in the low-cycle fatigue regime. This work explores the design and printing of yttria dispersion-hardened Ti-6Al-4V with minimal powder feedstock preparation. A uniformly dispersed yttria with a mean particle size of∼100 nm in the Ti-6Al-4V matrix decreases the transverse size of the prior beta grains. Furthermore, STEM bright-field micrographs reveal dispersoid pinning of dislocations, and STEM EDS confirms that the dispersoids are yttria as expected. A modest increase in room-temperature microhardness is observed, and room-temperature nanoindentation creep results show a∼64% lower mean creep rate compared to standard PBF-LB Ti-6Al-4V. Additionally, a room-temperature compression test was performed to determine the respective yield strengths to study cold creep, and its implications are discussed. At normalized stresses, ODS Ti-6Al-4V exhibits substantially lower long-term creep rates, albeit with greater initial deformation. This work successfully demonstrates the use of PBF-LB to fabricate oxide dispersion strengthened (ODS) Ti-6Al-4V, enabling refinement of the prior beta grains and improved long-term time-dependent deformation at normalized stresses. Bio Amaranth Karra is a postdoctoral researcher in the Department of Mechanical Engineering at the University of North Texas. He received his Ph.D. and M.S. in Materials Science and Engineering from Carnegie Mellon University. His research focuses on process metallurgy, additive manufacturing, and process–structure–property relationships in advanced metallic materials. His work spans laser powder bed fusion and