Novel β-type Zr–Mo–Ti alloys for biological hard tissue replacements

• β-Type Zr–Mo–Ti alloys are developed based on biocompatible elements.
• Ti element refines the microstructure.
• Solid solution of Mo and Ti determines the mechanical properties.
• Zr–12Mo–xTi alloys exhibit good combination of biomechanical properties.

In order to develop new biomaterials for hard tissue replacements, Zr–12Mo–xTi (x = 0, 3, 7 and 11, in at.%) alloys with required properties have been designed and prepared using vacuum arc melting method for the first time. Phase analysis and microstructural observation shows that all the as-cast samples consist of equiaxed β-Zr phase. Variations of lattice constants, volume and density of the Zr–12Mo–xTi alloys as a function of Ti content have been discussed. With the increase of Ti content, the microstructure is refined. The solid solution effect of the β-phase stabilization elements (i.e. Mo and Ti) predominantly determines the mechanical properties. These β-type Zr–12Mo–xTi alloys exhibit high compressive strength (1469–1584 MPa), high yield strength (1175–1375 MPa), high elastic energy (21–28 MJ/m3) and low Young’s modulus (32–35 GPa), together with plastic strain (11–25%). As the Zr–12Mo–xTi alloys are based on biocompatible elements, this good combination of biomechanical characteristics makes them potential biomedical materials for hard tissue replacements.