Novel high-temperature Ti-alloy for wire-based directed energy deposition

Description

We developed a novel high-temperature Ti-alloy designed for wire-based directed energy deposition (waDED) processes for additive manufacturing of large builds as required by the aerospace and energy industries. While high-strength Ti-alloys for waDED have been extensively researched, high-temperature variants are yet to be developed, even though most aerospace and energy components commonly operate at elevated temperatures. It is well-known that current waDED techniques often introduce significant heterogeneity and anisotropy in the mechanical properties, as seen in existing alloys including Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo. However, in our alloy design approach, we tried to minimize anisotropy and improve the high-temperature performance by leveraging phase transformations and precipitation to achieve fine, homogeneous microstructures during additive manufacturing. Our top candidate combines additions of Si, Cu, Nb, and Y. We investigate the microstructural evolution during simulated waDED solidification and various heat treatments associated with cyclic reheating. Our developed alloy exhibits refined, equiaxed β grains in as-built and heat-treated conditions. Y is shown to inhibit β grain growth, while Cu, Nb and Si contributed to a unique segregation and precipitation behaviour. High-resolution characterisation including atom probe microscopy reveals very fine (15–20 nm) core-shell Ti2Cu precipitates with Y cores, and Cu and Nb enrichment along characteristic α/α grain boundaries, significantly enhancing mechanical performance despite microstructure coarsening during the heat treatment. Our developed alloy shows substantial promise for high deposition-rate waDED processing, offering improved high-temperature properties.

Period	27 May 2026
Event title	20th European Mechanics of Materials Conference
Event type	Conference
Location	Florence, AustriaShow on map
Degree of Recognition	International