Development of Ti–26Nb–1.2TiC shape memory composite for biomedical applications

Ti–Nb alloys have great potential in biomedical applications as bone-implant materials due to their low elastic modulus, superelasticity, high corrosion resistance, and good biocompatibility. However, the low yield strength and poor superelasticity of Ti–Nb alloys restrict their practical clinical applications. Here, we report the mechanical properties and superelasticity, corrosion behavior, and biocompatibility of a Ti–26 at.% Nb–1.2 vol.% TiC (Ti–26Nb–1.2TiC) shape memory composite (SMC) prepared by vacuum arc melting and hot rolling. The yield strength, critical stress for inducing martensitic transformation, and elongation of the Ti–26Nb–1.2TiC SMC and a Ti–26Nb alloy were 460 and 337 MPa, 251 and 115 MPa, and 27.2% and 24.1%, respectively. The recovery rate of the SMC under 4% pre-strain reached 91.4%, which was 1.2 times that of the Ti–26Nb. Electrochemical tests in Hanks’ solution revealed that the corrosion current density, passive current density, and corrosion rate of the SMC were lower than those of the Ti–26Nb. Both the Ti–26Nb alloy and Ti–26Nb–1.2TiC SMC showed good cell viability with grade 0 cytotoxicity in relation to MG-63 osteosarcoma cells.