The effect of molybdenum content on the microstructural evolution and tensile properties of as-cast Ti-Mo alloys

The effect of Mo content on the microstructural evolution and the tensile properties of as-cast binary Ti-Mo alloys is designed by using the cluster-plus-glue atomic model and the β prediction method, such as the Mo_eq, e/a ratio and the d-electron, which were used to predict the stability of the β phase. The designed (Ti-10.02 wt % Mo, Ti-10.83 wt % Mo, Ti-12.89 wt % Mo and Ti-15.05 wt % Mo) alloys were fabricated by using the commercial arc re-melting furnace; and they were characterised for phase identification by using X-ray diffraction (XRD), the optical microscope (OM), the scanning electron microscope (SEM) and the electron backscatter diffraction (EBSD) techniques. The tensile properties of all the designed alloys were also analysed. The XRD spectra of all the designed alloys comprised the body-centred cubic (BCC) β phase and the orthorhombic martensitic (α″) phase. The orthorhombic martensitic peaks decreased with the increase in the Mo content. The Vickers microhardness (473.6, 440.6, 412.6 and 350.2 HV_0.5) and the elastic modulus (112.99, 105.7, 104.47 and 70.48 GPa) decreased significantly with an increase in the Mo content, from 10.02 wt % Mo to 15.05 wt % Mo, respectively. The ultimate tensile strength (UTS) decreased significantly (885.45, 643.10 and 593.48 MPa) with an increase in the concentration of Mo from 10.83 wt % to 15.05 wt %. The fractured surfaces after the tensile test showed that the as-cast Mo content increased while the brittle fractures became the dominant fractures.