Changes in the morphology and chemistry of an oxidation-sensitive beta-Ti alloy powder during the processing steps of additive manufacturing

Abstract

Compared to (α+β) titanium alloys, β titanium alloys exhibit a number of unique properties, such as a low modulus of elasticity and high yield strength combined with excellent formability. Among the these, Ti-Nb-Ta-Zr alloys are particularly attractive as structural materials, and additive manufacturing offers great potential for their processing due to the high process inherent dislocation density. Powder degradation during powder-based metal additive manufacturing, especially in case of oxygen-sensitive alloys, significantly affect powder reusability and hence rises economic and environmental concerns. Ti-Nb-Ta-Zr is particularly interesting in this respect, as all alloying elements are very susceptible to oxidation and oxygen itself is a very important alloying element for the phase composition and for the not yet fully understood thermally and stress induced phase transformations5 - and thus important component properties.