Simultaneous gettering of oxygen and chlorine and homogenization of the β phase by rare earth hydride additions to a powder metallurgy Ti-2.25Mo-1.5Fe alloy

A detailed transmission electron microscopy analysis has revealed that small additions of yttrium hydride to a powder metallurgy Ti-2.25Mo-1.5Fe alloy resulted in the formation of both chlorine-free yttrium oxides and essentially oxygen-free yttrium chlorides. The oxides and chlorides showed distinctly different morphologies and spatial distribution. Yttrium acted as a potent getter for both oxygen and chlorine. Additionally, the beta-Ti phase was free of nanoscaled alpha-Ti in the presence of yttrium. These microstructural changes contribute to the substantially increased ductility (similar to 90%). (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.