Changes in mechanical properties of Ti alloys in relation to alloying additions of Ta and Hf

The effects of Ta and Hf on the dynamic Youngʹs moduli and tensile properties of Ti–Ta and Ti–Hf alloys for biomedical applications are comparatively studied in this paper. It is found that with increasing Hf content, the dynamic Youngʹs modulus of the Ti–Hf alloy gently decreases and its tensile strength keeps on increasing. In contrast, with increasing Ta content, the dynamic Youngʹs modulus of the Ti–Ta alloys first decreases, reaches a minimum value of 69 GPa and then increases. In parallel, the tensile strength first increases, reaches a maximum value of 587 MPa, and then slightly decreases. It is shown that the addition of Hf has a slight influence on the dynamic Youngʹs modulus and a strong influence on the tensile properties of the Ti–Hf alloy, while an increase of Ta content has a strong effect on both the dynamic Youngʹs modulus and tensile properties of the Ti–Ta alloy.