Abstract

The unique microstructural features and thermal cycles in alloys produced by additive manufacturing (AM) techniques have led to the emergence of a new paradigm in the design and development of alloys for performance-critical applications. Despite the inherent microstructural features of AMed parts, optimizing the porosity-microstructure while acquiring desired mechanical performance has been crucial yet challenging. Hence, in many legacy alloys, achieving a strength-ductility synergy in the as-built condition without applying post-heat treatment or hybrid processes is considered an arduous task. In this research, we aimed to tailor the microstructure of the legacy Ti-6Al-4V alloy in the as-built condition by implementing the inoculation technique, as one of the recent techniques for microstructure control in AMed parts, to achieve an excellent combination of strength and ductility. Here, yttrium-rare earth element (REE) in its pure and oxide forms was used as an inoculant, which was decorated onto the Ti-6Al-4V alloy powder particles using the acoustic mixing method and, subsequently, the microstructure and mechanical properties of the directed energy deposited (DED) specimens were investigated. The FESEM, EBSD, and TEM microstructural investigations reveal that the Y and Y2O3 particles reacted in-situ during the printing process, leading to a distinct microstructure by forming new and dispersed precipitates. Specimens inoculated with the Y2O3, featuring a microstructure with plate-like and nearly equiaxed α phase and dispersed (Y,Ti)2O3 precipitates, exhibited uniform and excellent mechanical properties (e.g., UTS: ∼1280 MPa and elongation: ∼14%) in both horizontal and perpendicular directions in the as-printed condition. This research demonstrates that inoculation-based approaches can pave the way for achieving a strength-ductility synergy in as-built Ti-6Al-4V components with a minimal need for post-processing.

Department(s)

Materials Science and Engineering

Publication Status

Full Text Access

Comments

Korea Institute for Advancement of Technology, Grant RS-2024-00435406

Keywords and Phrases

Additive manufacturing; Grain structure control; Inoculation; Rare earth element; Strength-ductility; Ti-6Al-4V

International Standard Serial Number (ISSN)

0921-5093

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Elsevier, All rights reserved.

Publication Date

01 May 2026

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