Characterization of phase transformation and precipitation behavior in a novel Cu-modified near-α Ti alloy for additive manufacturing

Near α Ti-alloys are widely used for structural components up to service temperatures of 550 °C. While conventional manufacturing techniques prevail, additive manufacturing (AM) has gained significant interest recently due to its ability to produce complex geometries and efficient material usage. However, AM techniques have proven to be challenging fabrication processes with numerous variables affecting microstructure formation. Complex thermal conditions and a layer-wise build-up often lead to pronounced textures and, consequently, anisotropic mechanical properties. One fundamental way to address challenges such as microstructure formation during AM is the development of new alloying concepts. However, this relies on a profound understanding of the influence of the alloying elements on the material’s thermodynamics and transformation kinetics.
In this work, in-situ small-angle (SAXS) and wide-angle X-ray scattering (WAXS) experiments were performed to study a novel near α Ti alloy for high-temperature applications. In particular, the effect of Cu on the phase transformation and precipitation behavior was investigated. While WAXS provided insights into present phases under varying heat treatment conditions, the formation of nm sized intermetallic precipitates could be observed simultaneously by SAXS. The results of this study grant a deeper understanding of the complex phase evolution of a newly developed high temperature Ti alloy optimized for AM.