Strong and ductile titanium-oxygen-iron alloys by additive manufacturing.

Titanium alloys are advanced lightweight materials, indispensable for many critical applications 1,2 . The mainstay of the titanium industry is the α-β titanium alloys, which are formulated through alloying additions that stabilize the α and β phases 3-5 . Our work focuses on harnessing two of the most powerful stabilizing elements and strengtheners for α-β titanium alloys, oxygen and iron 1-5 , which are readily abundant. However, the embrittling effect of oxygen 6,7 , described colloquially as 'the kryptonite to titanium' 8 , and the microsegregation of iron 9 have hindered their combination for the development of strong and ductile α-β titanium-oxygen-iron alloys. Here we integrate alloy design with additive manufacturing (AM) process design to demonstrate a series of titanium-oxygen-iron compositions that exhibit outstanding tensile properties. We explain the atomic-scale origins of these properties using various characterization techniques. The abundance of oxygen and iron and the process simplicity for net-shape or near-net-shape manufacturing by AM make these α-β titanium-oxygen-iron alloys attractive for a diverse range of applications. Furthermore, they offer promise for industrial-scale use of off-grade sponge titanium or sponge titanium-oxygen-iron 10,11 , an industrial waste product at present. The economic and environmental potential to reduce the carbon footprint of the energy-intensive sponge titanium production 12 is substantial.