LAUSR

Since the excellent solid solution strengthening of the β-stabilizer (Co), Ti-24Nb-4Zr-XCo (X = 0.5, 1, 1.5 at.%) alloys are prepared in arc melting, cold rolled, and heat treated followed by air cooled (at 823 K and 1023 K for 1.2 ks). The results indicate that micro-additions of Co strongly affect the mechanical properties and corrosion resistance of β titanium alloys. XRD and OM analyses reveal that the Co enhances the recovery and recrystallization process and strengthens the stability of β phase against β → ω phase transformation. Tensile test and Vickers hardness test indicate that the tensile strength and hardness heighten with increasing Co content, while relatively high plastic strain is retained. The Ti-24Nb-4Zr-1.5Co alloy performs highest strength (about 700 MPa), high plastic strain (19%), and low elastic modulus (75 GPa), making it a prospective implant for biomedical applications. Electrochemical corrosion test shows that the corrosion resistance weakens with an increase in Co content due to effect of the ω phase, but addition of 1.5 Co can inhibit the precipitation of ω phase and prevent the deterioration to some extent.