A low-cost metastable beta Ti alloy with high elastic admissible strain and enhanced ductility for orthopaedic application

Abstract

In this work, a low-cost biomedical titanium alloy Ti–5Mo–Fe–3Sn (atomic percent) was successfully developed. The microstructure, tensile properties and deformation behaviour were investigated at ambient temperature. It was found that the combined addition of Sn and Fe suppressed the formation of athermal omega phase and introduced solid solution strengthening. An excellent combination of low elastic modulus (52 GPa) and high yield strength (740 MPa) was achieved, leading to a high elastic admissible strain (1.42%). Transmission electron microscopy results revealed that with an increase in tensile strain, the {332}<113> twin system was initiated first, and then secondary {332}<113> twinning and ternary {112}<111> twinning were also observed. The evolution of multi-twin system during deformation was responsible for the enhanced strain hardening rate and plasticity (elongation ∼30%).