Nanoprecipitation in a beta-titanium alloy

This paper represents the first application of small angle neutron scattering (SANS) to the study of precipitate nucleation and growth in beta-Ti alloys in an attempt to observe both the precipitation process in-situ and to quantify the evolving microstructure that affects mechanical behaviour. TEM suggests that athermal omega can be induced by cold-rolling Gum metal, a beta-Ti alloy. During thermal exposure at 400 degrees C, isothermal omega particles precipitate at a greater rate in cold-rolled material than in the recovered, hot deformed state. SANS modelling is consistent with disc shaped nanoparticles, with length and radius under 6 nm after thermal exposures up to 16 h. Modelling suggests that the nanoprecipitate volume fraction and extent of Nb partitioning to the beta matrix is greater in the cold-rolled material than the extruded. The results show that nucleation and growth of the nanoprecipitates impart strengthening to the alloy. (C) 2014 Elsevier B.V. All rights reserved.