Phase transformation and mechanical properties of the Ti50Zr30Nb10Ta10 alloy with low modulus and biocompatible

The beta transformation characteristics and mechanical properties of the β titanium alloy Ti50Zr30Nb10Ta10 in the temperature range between 200 and 900 °C have been studied by means of X-ray diffraction (XRD), Vickers hardness (HV), and tensile test techniques. In the as-rolled state, only β-phase was identified by XRD. Upon heat-treating at 250 °C for 4 h, the α-phase was precipitated from the β-phase matrix, and leading to an increase of Vickers hardness. A maximum HV value was observed at 400 °C, and then HV value decreased with increasing heat-treating temperature. Above 650 °C, HV value remained almost constant. During heat-treating at 300-650 °C, the decomposition of the metastable β-phase has been found to proceed through a phase separation reaction leading to the formation of β-Ti and β-Zr b.c.c. solid solution phases rather than the formation of solute rich and solute lean b.c.c. phases as has been previously reported, leading to little or no increase in HV value. The tensile strength, elongation and elastic modulus of Ti50Zr30Nb10Ta10 alloy for as-solution-treated samples are 741 MPa, 28.6% and 44 GPa, which is better than required values already reported.